import { parse } from 'acorn';
import { ancestor, recursive } from 'acorn-walk';
import escodegen from 'escodegen';
import { UnarySymbolToName } from './ir_types';
import * as FES from './strands_FES';
import {
  createStrandsShaderNameMap,
  createStrandsShaderNameState,
  getOrCreateInternalShaderName
} from './strands_names';
let blockVarCounter = 0;
let loopVarCounter = 0;
function replaceBinaryOperator(codeSource) {
  switch (codeSource) {
    case '+': return 'add';
    case '-': return 'sub';
    case '*': return 'mult';
    case '/': return 'div';
    case '%': return 'mod';
    case '==':
    case '===': return 'equalTo';
    case '!=':
    case '!==': return 'notEqual';
    case '>': return 'greaterThan';
    case '>=': return 'greaterEqual';
    case '<': return 'lessThan';
    case '<=': return 'lessEqual';
    case '&&': return 'and';
    case '||': return 'or';
    // TODO: handle ** --> pow, but make it stay pow in
    // GLSL instead of turning it back into **
  }
}
function nodeIsUniform(ancestor) {
  return ancestor && ancestor.type === 'CallExpression'
    && (
      (
        // Global mode
        ancestor.callee?.type === 'Identifier' &&
        ancestor.callee?.name.startsWith('uniform')
      ) || (
        // Instance mode
        ancestor.callee?.type === 'MemberExpression' &&
        ancestor.callee?.property.name.startsWith('uniform')
      )
    );
}

function nodeIsUniformCallbackFn(node, names) {
  if (!names?.size) return false;
  if (node.type === 'FunctionDeclaration' && names.has(node.id?.name)) return true;
  if (
    node.type === 'VariableDeclarator' && names.has(node.id?.name) &&
    (node.init?.type === 'FunctionExpression' || node.init?.type === 'ArrowFunctionExpression')
  ) {
    return true;
  }
  return false;
}

function collectUniformCallbackNames(ast) {
  // Sub-pass 1: collect all named function definitions
  const namedFunctions = new Set();
  ancestor(ast, {
    FunctionDeclaration(node) {
      if (node.id) namedFunctions.add(node.id.name);
    },
    VariableDeclarator(node) {
      if (
        node.id?.type === 'Identifier' &&
        (node.init?.type === 'FunctionExpression' || node.init?.type === 'ArrowFunctionExpression')
      ) {
        namedFunctions.add(node.id.name);
      }
    }
  });
  // Sub-pass 2: find which of those names are passed as uniform call arguments
  const names = new Set();
  ancestor(ast, {
    CallExpression(node) {
      if (nodeIsUniform(node)) {
        for (const arg of node.arguments) {
          if (arg.type === 'Identifier' && namedFunctions.has(arg.name)) {
            names.add(arg.name);
          }
        }
      }
    }
  });
  return names;
}

function nodeIsVarying(node) {
  return node && node.type === 'CallExpression'
    && (
      (
        // Global mode
        node.callee?.type === 'Identifier' &&
        (node.callee?.name.startsWith('varying') || node.callee?.name.startsWith('shared'))
      ) || (
        // Instance mode
        node.callee?.type === 'MemberExpression' &&
        (node.callee?.property.name.startsWith('varying') || node.callee?.property.name.startsWith('shared'))
      )
    );
}
// Convert static member expressions into dotted paths such as
// `loopProtect.protect` so loop-protection calls can be matched reliably.
function getMemberExpressionPath(node) {
  if (node?.type === 'Identifier') return node.name;

  // Computed properties like `obj[prop]` are not safe to match as fixed paths.
  if (node?.type !== 'MemberExpression' || node.computed) return null;

  const objectPath = getMemberExpressionPath(node.object);
  const propertyName = node.property?.name;

  return objectPath && propertyName
    ? `${objectPath}.${propertyName}`
    : null;
}

// Detect calls added by loop protection before Strands tries to transpile them.
function isLoopProtectionCall(node) {
  if (node?.type !== 'CallExpression') return false;

  const path = getMemberExpressionPath(node.callee);

  if (!path) return false;

  return (
    path === 'loopProtect.protect' ||
    path.endsWith('.loopProtect') ||
    path.endsWith('.loopProtect.protect')
  );
}

// Scan AST for loop-protection injection and throw with `// noprotect` hint.
function throwIfLoopProtectionInserted(ast) {
  let found = false;

  ancestor(ast, {
    CallExpression(node) {
      if (isLoopProtectionCall(node)) {
        found = true;
      }
    },
    LogicalExpression(node) {
      // Loop protection may appear as the right side of a short-circuit check.
      if (
        node.right?.type === 'CallExpression' &&
        isLoopProtectionCall(node.right)
      ) {
        found = true;
      }
    }
  });

  if (found) {
    FES.internalError(
      'loop protection error Loop protection code detected. Add `// noprotect` at the top of your sketch and run again.'
    );
  }
}
// Helper function to check if a statement is a variable declaration with strands control flow init
function statementContainsStrandsControlFlow(stmt) {
  // Check for variable declarations with strands control flow init
  if (stmt.type === 'VariableDeclaration') {
    const match = stmt.declarations.some(decl =>
      decl.init?.type === 'CallExpression' &&
      (
        (
          decl.init?.callee?.type === 'MemberExpression' &&
          decl.init?.callee?.object?.type === 'Identifier' &&
          decl.init?.callee?.object?.name === '__p5' &&
          (decl.init?.callee?.property?.name === 'strandsFor' ||
            decl.init?.callee?.property?.name === 'strandsIf')
        ) ||
        (
          decl.init?.callee?.type === 'Identifier' &&
          (decl.init?.callee?.name === '__p5.strandsFor' ||
            decl.init?.callee?.name === '__p5.strandsIf')
        )
      )
    );
    return match
  }
  return false;
}

// Helper function to build property path from MemberExpression
// e.g., inputs.color -> "inputs.color", vec.x -> "vec.x"
function isSwizzle(propertyName) {
  if (!propertyName || typeof propertyName !== 'string') return false;
  const swizzleSets = [
    ['x', 'y', 'z', 'w'],
    ['r', 'g', 'b', 'a'],
    ['s', 't', 'p', 'q']
  ];
  return swizzleSets.some(set =>
    [...propertyName].every(char => set.includes(char))
  );
}

function buildPropertyPath(memberExpr) {
  const parts = [];
  let current = memberExpr;
  while (current.type === 'MemberExpression') {
    if (current.computed) {
      return null;
    }
    const propName = current.property.name || current.property.value;
    if (isSwizzle(propName)) {
      current = current.object;
      break;
    }
    parts.unshift(propName);
    current = current.object;
  }
  if (current.type === 'Identifier') {
    parts.unshift(current.name);
  } else {
    return null;
  }
  return parts.join('.');
}

// Replace all references to original variables with temp variables
// and wrap literal assignments in strandsNode calls
function replaceReferences(node, tempVarMap) {
  const internalReplaceReferences = (node) => {
    if (!node || typeof node !== 'object') return;

    // Check if this MemberExpression matches a tracked property path
    if (node.type === 'MemberExpression') {
      const propName = node.property.name || node.property.value;
      if (isSwizzle(propName)) {
        // For swizzles, only replace the object part, keep the swizzle
        internalReplaceReferences(node.object);
        return;
      }
      const propertyPath = buildPropertyPath(node);
      if (propertyPath && tempVarMap.has(propertyPath)) {
        // Replace entire member expression with temp variable
        Object.assign(node, {
          type: 'Identifier',
          name: tempVarMap.get(propertyPath)
        });
        return; // Don't recurse into replaced node
      }
    }

    // Handle simple identifier replacements
    if (node.type === 'Identifier' && tempVarMap.has(node.name)) {
      node.name = tempVarMap.get(node.name);
    }

    // Handle literal assignments to temp variables
    if (node.type === 'AssignmentExpression') {
      let leftPath = null;
      if (node.left.type === 'Identifier') {
        leftPath = node.left.name;
      } else if (node.left.type === 'MemberExpression') {
        leftPath = buildPropertyPath(node.left);
      }

      if (leftPath && tempVarMap.has(leftPath) &&
          (node.right.type === 'Literal' || node.right.type === 'ArrayExpression')) {
        // Wrap the right hand side in a strandsNode call to make sure
        // it's not just a literal and has a type
        node.right = {
          type: 'CallExpression',
          callee: {
            type: 'Identifier',
            name: '__p5.strandsNode'
          },
          arguments: [node.right]
        };
      }
    }

    // Recursively process all properties
    for (const key in node) {
      if (node.hasOwnProperty(key) && key !== 'parent') {
        // Don't recurse into property names of non-computed member expressions
        if (node.type === 'MemberExpression' && key === 'property' && !node.computed) {
          continue;
        }
        if (Array.isArray(node[key])) {
          node[key].forEach(internalReplaceReferences);
        } else if (typeof node[key] === 'object') {
          internalReplaceReferences(node[key]);
        }
      }
    }
  };

  internalReplaceReferences(node);
}

function replaceIdentifierReferences(node, oldName, newName) {
  if (!node || typeof node !== 'object') return node;

  const replaceInNode = (n) => {
    if (!n || typeof n !== 'object') return n;
    if (n.type === 'Identifier' && n.name === oldName) {
      return { ...n, name: newName };
    }
    const newNode = { ...n };
    for (const key in n) {
      if (n.hasOwnProperty(key) && key !== 'parent') {
        if (Array.isArray(n[key])) {
          newNode[key] = n[key].map(replaceInNode);
        } else if (typeof n[key] === 'object') {
          newNode[key] = replaceInNode(n[key]);
        }
      }
    }
    return newNode;
  };

  return replaceInNode(node);
}

// Shared handler for both BinaryExpression and LogicalExpression —
// both follow the same operator-to-method-call transformation pattern.
function transformBinaryOrLogical(node, state, ancestors) {
  if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
    return;
  }
  node.left = {
    type: 'CallExpression',
    callee: {
      type: 'Identifier',
      name: '__p5.strandsNode',
    },
    arguments: [node.left]
  };
  node.type = 'CallExpression';
  node.callee = {
    type: 'MemberExpression',
    object: node.left,
    property: {
      type: 'Identifier',
      name: replaceBinaryOperator(node.operator),
    },
  };
  node.arguments = [node.right];
}

// Shared helper used by both IfStatement and ForStatement handlers.
// Adds temp variable copies, replaces references, and appends a return
// statement to a branch/loop function body.
// sourcePrefix: the root identifier to read from ('vars' for loops,
// null for if-branches where we read directly from the outer variable).
function addCopyingAndReturn(functionBody, varsToReturn, sourcePrefix = null) {
  if (functionBody.type !== 'BlockStatement') return;

  const tempVarMap = new Map();
  const copyStatements = [];

  for (const varPath of varsToReturn) {
    const parts = varPath.split('.');
    const tempName = `__copy_${parts.join('_')}_${blockVarCounter++}`;
    tempVarMap.set(varPath, tempName);

    // If sourcePrefix is set (loop case), read from vars.x.y
    // Otherwise (if-branch case), read directly from x.y
    let sourceExpr = sourcePrefix
      ? { type: 'Identifier', name: sourcePrefix }
      : { type: 'Identifier', name: parts[0] };

    const pathParts = sourcePrefix ? parts : parts.slice(1);
    for (const part of pathParts) {
      sourceExpr = {
        type: 'MemberExpression',
        object: sourceExpr,
        property: { type: 'Identifier', name: part },
        computed: false
      };
    }

    copyStatements.push({
      type: 'VariableDeclaration',
      declarations: [{
        type: 'VariableDeclarator',
        id: { type: 'Identifier', name: tempName },
        init: {
          type: 'CallExpression',
          callee: {
            type: 'MemberExpression',
            object: sourceExpr,
            property: { type: 'Identifier', name: 'copy' },
            computed: false
          },
          arguments: []
        }
      }],
      kind: 'let'
    });
  }

  functionBody.body.forEach(node => replaceReferences(node, tempVarMap));
  functionBody.body.unshift(...copyStatements);

  const returnObj = {
    type: 'ObjectExpression',
    properties: Array.from(varsToReturn).map(varPath => ({
      type: 'Property',
      key: { type: 'Literal', value: varPath },
      value: { type: 'Identifier', name: tempVarMap.get(varPath) },
      kind: 'init',
      computed: false,
      shorthand: false
    }))
  };

  functionBody.body.push({
    type: 'ReturnStatement',
    argument: returnObj
  });
}

const ASTCallbacks = {
  UnaryExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    const unaryFnName = UnarySymbolToName[node.operator];
    const standardReplacement = (node) => {
      node.type = 'CallExpression'
      node.callee = {
        type: 'Identifier',
        name: `__p5.${unaryFnName}`,
      }
      node.arguments = [node.argument]
    }
    if (node.type === 'MemberExpression') {
      const property = node.argument.property.name;
      const swizzleSets = [
        ['x', 'y', 'z', 'w'],
        ['r', 'g', 'b', 'a'],
        ['s', 't', 'p', 'q']
      ];
      let isSwizzle = swizzleSets.some(set =>
        [...property].every(char => set.includes(char))
      ) && node.argument.type === 'MemberExpression' && !node.argument.computed;
      if (isSwizzle) {
        node.type = 'MemberExpression';
        node.object = {
          type: 'CallExpression',
          callee: {
            type: 'Identifier',
            name: `__p5.${unaryFnName}`
          },
          arguments: [node.argument.object],
        };
        node.property = {
          type: 'Identifier',
          name: property
        };
      } else {
        standardReplacement(node);
      }
    } else {
      standardReplacement(node);
    }
    delete node.argument;
    delete node.operator;
  },
  BreakStatement(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    node.callee = {
      type: 'Identifier',
      name: '__p5.break'
    };
    node.arguments = [];
    node.type = 'CallExpression';
  },
  MemberExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    // Skip sets -- these will be converted to .set() method
    // calls at the AssignmentExpression level
    if (
      ancestors.at(-2)?.type === 'AssignmentExpression' &&
      ancestors.at(-2).left === node
    ) {
      return;
    }
    if (node.computed) {
      const callee = node.object;
      const member = node.property;
      node.computed = undefined;
      node.object = undefined;
      node.callee = {
        type: 'MemberExpression',
        object: callee,
        property: {
          type: 'Identifier',
          name: 'get',
        }
      };
      node.arguments = [member];
      node.type = 'CallExpression';
    }
  },
  VariableDeclarator(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    if (nodeIsUniform(node.init)) {
      // Only inject the variable name if the first argument isn't already a string
      if (node.init.arguments.length === 0 ||
          node.init.arguments[0].type !== 'Literal' ||
          typeof node.init.arguments[0].value !== 'string') {
        const uniformName = getOrCreateInternalShaderName(
          state.shaderNameMap,
          state.shaderNameState,
          node.id.name
        );
        const uniformNameLiteral = {
          type: 'Literal',
          value: uniformName
        };
        node.init.arguments.unshift(uniformNameLiteral);
      }
    }
    if (nodeIsVarying(node.init)) {
      // Only inject the variable name if the first argument isn't already a string
      if (
        node.init.arguments.length === 0 ||
        node.init.arguments[0].type !== 'Literal' ||
        typeof node.init.arguments[0].value !== 'string'
      ) {
        const varyingName = getOrCreateInternalShaderName(
          state.shaderNameMap,
          state.shaderNameState,
          node.id.name
        );
        const varyingNameLiteral = {
          type: 'Literal',
          value: varyingName
        };
        node.init.arguments.unshift(varyingNameLiteral);
        state.varyings[node.id.name] = varyingNameLiteral;
      } else {
        // Still track it as a varying even if name wasn't injected
        state.varyings[node.id.name] = node.init.arguments[0];
      }
    }
  },
  Identifier(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    if (state.varyings[node.name]
      && !ancestors.some(a => a.type === 'AssignmentExpression' && a.left === node)
    ) {
      node.type = 'CallExpression';
      node.callee = {
        type: 'MemberExpression',
        object: {
          type: 'Identifier',
          name: node.name
        },
        property: {
          type: 'Identifier',
          name: 'getValue'
        },
      };
      node.arguments = [];
    }
  },
  // The callbacks for AssignmentExpression and BinaryExpression handle
  // operator overloading including +=, *= assignment expressions
  ArrayExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }

    if (node.elements.length < 2 || node.elements.length > 4) {
      FES.userError(
        'type error',
        `Array literals in shader functions are transpiled to vectors and must have 2-4 elements (got ${node.elements.length}).`
      );
    }

    const original = JSON.parse(JSON.stringify(node));
    node.type = 'CallExpression';
    node.callee = {
      type: 'Identifier',
      name: '__p5.strandsNode',
    };
    node.arguments = [original];
  },
  AssignmentExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    const unsafeTypes = ['Literal', 'ArrayExpression', 'Identifier'];
    if (node.operator !== '=') {
      const methodName = replaceBinaryOperator(node.operator.replace('=',''));
      const rightReplacementNode = {
        type: 'CallExpression',
        callee: {
          type: 'MemberExpression',
          object: unsafeTypes.includes(node.left.type)
            ? {
                type: 'CallExpression',
                callee: {
                  type: 'Identifier',
                  name: '__p5.strandsNode',
                },
                arguments: [node.left]
              }
            : node.left,
          property: {
            type: 'Identifier',
            name: methodName,
          },
        },
        arguments: [node.right]
      }
      node.operator = '=';
      node.right = rightReplacementNode;
    }
    // Handle direct varying variable assignment: myVarying = value
    if (state.varyings[node.left.name]) {
      node.type = 'ExpressionStatement';
      node.expression = {
        type: 'CallExpression',
        callee: {
          type: 'MemberExpression',
          object: {
            type: 'Identifier',
            name: node.left.name
          },
          property: {
            type: 'Identifier',
            name: 'bridge',
          }
        },
        arguments: [node.right],
      }
    }
    // Handle swizzle assignment to varying variable: myVarying.xyz = value
    // Note: node.left.object might be worldPos.getValue() due to prior Identifier transformation
    else if (node.left.type === 'MemberExpression') {
      if (node.left.computed) {
        const source = node.left;
        const value = node.right;
        const callee = source.object;
        const member = source.property;
        node.right = undefined;
        node.left = undefined;
        node.operator = undefined;
        node.callee = {
          type: 'MemberExpression',
          object: callee,
          property: {
            type: 'Identifier',
            name: 'set'
          }
        };
        node.arguments = [member, value];
        node.type = 'CallExpression';
        return;
      }

      let varyingName = null;

      // Check if it's a direct identifier: myVarying.xyz
      if (node.left.object.type === 'Identifier' && state.varyings[node.left.object.name]) {
        varyingName = node.left.object.name;
      }
      // Check if it's a getValue() call: myVarying.getValue().xyz
      else if (node.left.object.type === 'CallExpression' &&
               node.left.object.callee?.type === 'MemberExpression' &&
               node.left.object.callee.property?.name === 'getValue' &&
               node.left.object.callee.object?.type === 'Identifier' &&
               state.varyings[node.left.object.callee.object.name]) {
        varyingName = node.left.object.callee.object.name;
      }

      if (varyingName) {
        const swizzlePattern = node.left.property.name;
        node.type = 'ExpressionStatement';
        node.expression = {
          type: 'CallExpression',
          callee: {
            type: 'MemberExpression',
            object: {
              type: 'Identifier',
              name: varyingName
            },
            property: {
              type: 'Identifier',
              name: 'bridgeSwizzle',
            }
          },
          arguments: [
            {
              type: 'Literal',
              value: swizzlePattern
            },
            node.right
          ],
        }
      }
    }
  },
  BinaryExpression: transformBinaryOrLogical,
  LogicalExpression: transformBinaryOrLogical,


  ConditionalExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    // Transform condition ? consequent : alternate
    // into __p5.strandsTernary(condition, consequent, alternate)
    const test = node.test;
    const consequent = node.consequent;
    const alternate = node.alternate;
    node.type = 'CallExpression';
    node.callee = { type: 'Identifier', name: '__p5.strandsTernary' };
    node.arguments = [test, consequent, alternate];
    delete node.test;
    delete node.consequent;
    delete node.alternate;
  },
  IfStatement(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }
    // Transform if statement into strandsIf() call
    // The condition is evaluated directly, not wrapped in a function
    const condition = node.test;
    // Create the then function
    const thenFunction = {
      type: 'ArrowFunctionExpression',
      params: [],
      body: node.consequent.type === 'BlockStatement' ? node.consequent : {
        type: 'BlockStatement',
        body: [node.consequent]
      }
    };
    // Start building the call chain: __p5.strandsIf(condition, then)
    let callExpression = {
      type: 'CallExpression',
      callee: {
        type: 'Identifier',
        name: '__p5.strandsIf'
      },
      arguments: [condition, thenFunction]
    };
    // Always chain .Else() even if there's no explicit else clause
    // This ensures the conditional completes and returns phi nodes
    let elseFunction;
    if (node.alternate) {
      elseFunction = {
        type: 'ArrowFunctionExpression',
        params: [],
        body: node.alternate.type === 'BlockStatement' ? node.alternate : {
          type: 'BlockStatement',
          body: [node.alternate]
        }
      };
    } else {
      // Create an empty else function
      elseFunction = {
        type: 'ArrowFunctionExpression',
        params: [],
        body: {
          type: 'BlockStatement',
          body: []
        }
      };
    }
    callExpression = {
      type: 'CallExpression',
      callee: {
        type: 'MemberExpression',
        object: callExpression,
        property: {
          type: 'Identifier',
          name: 'Else'
        }
      },
      arguments: [elseFunction]
    };

    // Analyze which outer scope variables are assigned in any branch
    const assignedVars = new Set();

    const analyzeBranch = (functionBody) => {
      // First pass: collect all variable declarations in the branch
      const localVars = new Set();
      ancestor(functionBody, {
        VariableDeclarator(node, ancestors) {
          // Skip if we're inside a block that contains strands control flow
          if (ancestors.some(statementContainsStrandsControlFlow)) return;
          if (node.id.type === 'Identifier') {
            localVars.add(node.id.name);
          }
        }
      });

      // Second pass: find assignments to non-local variables using acorn-walk
      ancestor(functionBody, {
        AssignmentExpression(node, ancestors) {
          // Skip if we're inside a block that contains strands control flow
          if (ancestors.some(statementContainsStrandsControlFlow)) return;

          const left = node.left;
          if (left.type === 'Identifier') {
            // Direct variable assignment: x = value
            if (!localVars.has(left.name)) {
              assignedVars.add(left.name);
            }
          } else if (left.type === 'MemberExpression') {
            // Property assignment: obj.prop = value or obj.a.b = value
            const propertyPath = buildPropertyPath(left);
            if (propertyPath) {
              const baseName = propertyPath.split('.')[0];
              if (!localVars.has(baseName)) {
                assignedVars.add(propertyPath);
              }
            }
          }
        }
      });
    };

    // Analyze all branches for assignments to outer scope variables
    analyzeBranch(thenFunction.body);
    analyzeBranch(elseFunction.body);
    if (assignedVars.size > 0) {
      addCopyingAndReturn(thenFunction.body, assignedVars);
      addCopyingAndReturn(elseFunction.body, assignedVars);
      // Create a block variable to capture the return value
      const blockVar = `__block_${blockVarCounter++}`;
      // Replace with a block statement
      const statements = [];
      // Make sure every assigned variable starts as a node
      for (const varPath of assignedVars) {
        const parts = varPath.split('.');

        // Build left side: inputs.color or just x
        let leftExpr = { type: 'Identifier', name: parts[0] };
        for (let i = 1; i < parts.length; i++) {
          leftExpr = {
            type: 'MemberExpression',
            object: leftExpr,
            property: { type: 'Identifier', name: parts[i] },
            computed: false
          };
        }

        // Build right side - same as left for strandsNode wrapping
        let rightArgExpr = { type: 'Identifier', name: parts[0] };
        for (let i = 1; i < parts.length; i++) {
          rightArgExpr = {
            type: 'MemberExpression',
            object: rightArgExpr,
            property: { type: 'Identifier', name: parts[i] },
            computed: false
          };
        }

        statements.push({
          type: 'ExpressionStatement',
          expression: {
            type: 'AssignmentExpression',
            operator: '=',
            left: leftExpr,
            right: {
              type: 'CallExpression',
              callee: { type: 'Identifier', name: '__p5.strandsNode' },
              arguments: [rightArgExpr],
            }
          }
        });
      }
      statements.push({
        type: 'VariableDeclaration',
        declarations: [{
          type: 'VariableDeclarator',
          id: { type: 'Identifier', name: blockVar },
          init: callExpression
        }],
        kind: 'const'
      });
      // 2. Assignments for each modified variable
      for (const varPath of assignedVars) {
        const parts = varPath.split('.');

        // Build left side: inputs.color or just x
        let leftExpr = { type: 'Identifier', name: parts[0] };
        for (let i = 1; i < parts.length; i++) {
          leftExpr = {
            type: 'MemberExpression',
            object: leftExpr,
            property: { type: 'Identifier', name: parts[i] },
            computed: false
          };
        }

        // Build right side: __block_2['inputs.color'] or __block_2['x']
        const rightExpr = {
          type: 'MemberExpression',
          object: { type: 'Identifier', name: blockVar },
          property: { type: 'Literal', value: varPath },
          computed: true
        };

        statements.push({
          type: 'ExpressionStatement',
          expression: {
            type: 'AssignmentExpression',
            operator: '=',
            left: leftExpr,
            right: rightExpr
          }
        });
      }
      // Replace the if statement with a block statement
      node.type = 'BlockStatement';
      node.body = statements;
    } else {
      // No assignments, just replace with the call expression
      node.type = 'ExpressionStatement';
      node.expression = callExpression;
    }
    delete node.test;
    delete node.consequent;
    delete node.alternate;
  },
  UpdateExpression(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }

    // Transform ++var, var++, --var, var-- into assignment expressions
    let operator;
    if (node.operator === '++') {
      operator = '+';
    } else if (node.operator === '--') {
      operator = '-';
    } else {
      return; // Unknown update operator
    }

    // Convert to: var = var + 1 or var = var - 1
    const assignmentExpr = {
      type: 'AssignmentExpression',
      operator: '=',
      left: node.argument,
      right: {
        type: 'BinaryExpression',
        operator: operator,
        left: node.argument,
        right: {
          type: 'Literal',
          value: 1
        }
      }
    };

    // Replace the update expression with the assignment expression
    Object.assign(node, assignmentExpr);
    delete node.prefix;
    ASTCallbacks.BinaryExpression(node.right, state, [...ancestors, node]);
    ASTCallbacks.AssignmentExpression(node, state, ancestors);
  },
  ForStatement(node, state, ancestors) {
    if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, state.uniformCallbackNames))) {
      return;
    }

    // Transform for statement into strandsFor() call
    // for (init; test; update) body -> strandsFor(initCb, conditionCb, updateCb, bodyCb, initialVars)

    // Generate unique loop variable name
    const uniqueLoopVar = `loopVar${loopVarCounter++}`;

    // Create the initial callback from the for loop's init
    let initialFunction;
    if (node.init && node.init.type === 'VariableDeclaration') {
      // Handle: for (let i = 0; ...)
      const declaration = node.init.declarations[0];
      let initValue = declaration.init;

      const initAst = { type: 'Program', body: [{ type: 'ExpressionStatement', expression: initValue }] };
      initValue = initAst.body[0].expression;

      initialFunction = {
        type: 'ArrowFunctionExpression',
        params: [],
        body: {
          type: 'BlockStatement',
          body: [{
            type: 'ReturnStatement',
            argument: initValue
          }]
        }
      };
    } else {
      // Handle other cases - return a default value
      initialFunction = {
        type: 'ArrowFunctionExpression',
        params: [],
        body: {
          type: 'BlockStatement',
          body: [{
            type: 'ReturnStatement',
            argument: {
              type: 'Literal',
              value: 0
            }
          }]
        }
      };
    }

    // Create the condition callback
    let conditionBody = node.test || { type: 'Literal', value: true };
    // Replace loop variable references with the parameter
    if (node.init?.type === 'VariableDeclaration') {
      const loopVarName = node.init.declarations[0].id.name;
      conditionBody = replaceIdentifierReferences(conditionBody, loopVarName, uniqueLoopVar);
    }
    const conditionAst = { type: 'Program', body: [{ type: 'ExpressionStatement', expression: conditionBody }] };
    conditionBody = conditionAst.body[0].expression;

    const conditionFunction = {
      type: 'ArrowFunctionExpression',
      params: [{ type: 'Identifier', name: uniqueLoopVar }],
      body: conditionBody
    };

    // Create the update callback
    let updateFunction;
    if (node.update) {
      let updateExpr = node.update;
      // Replace loop variable references with the parameter
      if (node.init?.type === 'VariableDeclaration') {
        const loopVarName = node.init.declarations[0].id.name;
        updateExpr = replaceIdentifierReferences(updateExpr, loopVarName, uniqueLoopVar);
      }
      const updateAst = { type: 'Program', body: [{ type: 'ExpressionStatement', expression: updateExpr }] };
      updateExpr = updateAst.body[0].expression;

      updateFunction = {
        type: 'ArrowFunctionExpression',
        params: [{ type: 'Identifier', name: uniqueLoopVar }],
        body: {
          type: 'BlockStatement',
          body: [{
            type: 'ReturnStatement',
            argument: updateExpr
          }]
        }
      };
    } else {
      updateFunction = {
        type: 'ArrowFunctionExpression',
        params: [{ type: 'Identifier', name: uniqueLoopVar }],
        body: {
          type: 'BlockStatement',
          body: [{
            type: 'ReturnStatement',
            argument: { type: 'Identifier', name: uniqueLoopVar }
          }]
        }
      };
    }

    // Create the body callback
    let bodyBlock = node.body.type === 'BlockStatement' ? node.body : {
      type: 'BlockStatement',
      body: [node.body]
    };

    // Replace loop variable references in the body
    if (node.init?.type === 'VariableDeclaration') {
      const loopVarName = node.init.declarations[0].id.name;
      bodyBlock = replaceIdentifierReferences(bodyBlock, loopVarName, uniqueLoopVar);
    }

    const bodyFunction = {
      type: 'ArrowFunctionExpression',
      params: [
        { type: 'Identifier', name: uniqueLoopVar },
        { type: 'Identifier', name: 'vars' }
      ],
      body: bodyBlock
    };

    // Analyze which outer scope variables are assigned in the loop body
    const assignedVars = new Set();

    // First pass: collect all variable declarations in the body
    const localVars = new Set();
    ancestor(bodyFunction.body, {
      VariableDeclarator(node, ancestors) {
        // Skip if we're inside a block that contains strands control flow
        if (ancestors.some(statementContainsStrandsControlFlow)) return;
        if (node.id.type === 'Identifier') {
          localVars.add(node.id.name);
        }
      }
    });

    // Second pass: find assignments to non-local variables using acorn-walk
    ancestor(bodyFunction.body, {
      AssignmentExpression(node, ancestors) {
        // Skip if we're inside a block that contains strands control flow
        if (ancestors.some(statementContainsStrandsControlFlow)) {
          return
        }

        const left = node.left;
        if (left.type === 'Identifier') {
          // Direct variable assignment: x = value
          if (!localVars.has(left.name)) {
            assignedVars.add(left.name);
          }
        } else if (left.type === 'MemberExpression') {
          // Property assignment: obj.prop = value or obj.a.b = value
          const propertyPath = buildPropertyPath(left);
          if (propertyPath) {
            const baseName = propertyPath.split('.')[0];
            if (!localVars.has(baseName)) {
              assignedVars.add(propertyPath);
            }
          }
        }
      }
    });

    if (assignedVars.size > 0) {

      addCopyingAndReturn(bodyFunction.body, assignedVars, 'vars');

      // Create block variable and assignments similar to if statements
      const blockVar = `__block_${blockVarCounter++}`;
      const statements = [];

      const initialVarsObject = {
        type: 'ObjectExpression',
        properties: Array.from(assignedVars).map(varPath => {
          const parts = varPath.split('.');
          let expr = { type: 'Identifier', name: parts[0] };
          for (let i = 1; i < parts.length; i++) {
            expr = {
              type: 'MemberExpression',
              object: expr,
              property: { type: 'Identifier', name: parts[i] },
              computed: false
            };
          }
          const wrappedExpr = {
            type: 'CallExpression',
            callee: { type: 'Identifier', name: '__p5.strandsNode' },
            arguments: [expr]
          };
          return {
            type: 'Property',
            key: { type: 'Literal', value: varPath },
            value: wrappedExpr,
            kind: 'init',
            computed: false,
            shorthand: false
          };
        })
      };

      // Create the strandsFor call
      const callExpression = {
        type: 'CallExpression',
        callee: {
          type: 'Identifier',
          name: '__p5.strandsFor'
        },
        arguments: [initialFunction, conditionFunction, updateFunction, bodyFunction, initialVarsObject]
      };

      statements.push({
        type: 'VariableDeclaration',
        declarations: [{
          type: 'VariableDeclarator',
          id: { type: 'Identifier', name: blockVar },
          init: callExpression
        }],
        kind: 'const'
      });

      // Add assignments back to original variables
      for (const varPath of assignedVars) {
        const parts = varPath.split('.');

        // Build left side: inputs.color or just x
        let leftExpr = { type: 'Identifier', name: parts[0] };
        for (let i = 1; i < parts.length; i++) {
          leftExpr = {
            type: 'MemberExpression',
            object: leftExpr,
            property: { type: 'Identifier', name: parts[i] },
            computed: false
          };
        }

        // Build right side: __block_2.inputs.color or __block_2.x
        let rightExpr = { type: 'Identifier', name: blockVar };
        for (const part of parts) {
          rightExpr = {
            type: 'MemberExpression',
            object: rightExpr,
            property: { type: 'Identifier', name: part },
            computed: false
          };
        }

        statements.push({
          type: 'ExpressionStatement',
          expression: {
            type: 'AssignmentExpression',
            operator: '=',
            left: leftExpr,
            right: rightExpr
          }
        });
      }

      node.type = 'BlockStatement';
      node.body = statements;
    } else {
      // No assignments, just replace with call expression
      node.type = 'ExpressionStatement';
      node.expression = {
        type: 'CallExpression',
        callee: {
          type: 'Identifier',
          name: '__p5.strandsFor'
        },
        arguments: [initialFunction, conditionFunction, updateFunction, bodyFunction, {
          type: 'ObjectExpression',
          properties: []
        }]
      };
    }

    delete node.init;
    delete node.test;
    delete node.update;
  },



}

// Helper function to check if a function body contains return statements in control flow
function functionHasEarlyReturns(functionNode) {
  let hasEarlyReturn = false;
  let inControlFlow = 0;

  const checkForEarlyReturns = {
    IfStatement(node, state, c) {
      inControlFlow++;
      if (node.test) c(node.test, state);
      if (node.consequent) c(node.consequent, state);
      if (node.alternate) c(node.alternate, state);
      inControlFlow--;
    },
    ForStatement(node, state, c) {
      inControlFlow++;
      if (node.init) c(node.init, state);
      if (node.test) c(node.test, state);
      if (node.update) c(node.update, state);
      if (node.body) c(node.body, state);
      inControlFlow--;
    },
    ReturnStatement(node) {
      if (inControlFlow > 0) {
        hasEarlyReturn = true;
      }
    }
  };

  if (functionNode.body && functionNode.body.type === 'BlockStatement') {
    recursive(functionNode.body, {}, checkForEarlyReturns);
  }

  return hasEarlyReturn;
}

// Helper function to check if a block contains a return anywhere in it
function blockContainsReturn(block) {
  let hasReturn = false;
  const findReturn = {
    ReturnStatement() {
      hasReturn = true;
    }
  };
  if (block) {
    recursive(block, {}, findReturn);
  }
  return hasReturn;
}

// Transform a helper function to use __returnValue pattern instead of early returns.
// This is necessary because we evaluate helper function *in javascript* rather than
// converting them to functions in GLSL (which is hard because we don't know the types
// of function parameters upfront, and they may change from use to use.) So they act
// like macros, all contributing to build up a single function overall. An early return
// in a helper should not be an early return of the entire hook function. Instead, we
// just make sure helper functions always evaluate to a single value.
function transformHelperFunction(functionNode) {
  // 1. Add __returnValue declaration at the start of function body
  const returnValueDecl = {
    type: 'VariableDeclaration',
    declarations: [{
      type: 'VariableDeclarator',
      id: { type: 'Identifier', name: '__returnValue' },
      init: null
    }],
    kind: 'let'
  };

  if (!functionNode.body || functionNode.body.type !== 'BlockStatement') {
    return; // Can't transform arrow functions with expression bodies
  }

  functionNode.body.body.unshift(returnValueDecl);

  // 2. Restructure if statements: move siblings after if with return into else block
  function restructureIfStatements(statements) {
    for (let i = 0; i < statements.length; i++) {
      const stmt = statements[i];

      if (stmt.type === 'IfStatement' && blockContainsReturn(stmt.consequent) && !stmt.alternate) {
        // Find all subsequent statements
        const subsequentStatements = statements.slice(i + 1);

        if (subsequentStatements.length > 0) {
          // Create else block with subsequent statements
          stmt.alternate = {
            type: 'BlockStatement',
            body: subsequentStatements
          };

          // Remove the subsequent statements from this level
          statements.splice(i + 1);

          // Recursively process the new else block
          restructureIfStatements(stmt.alternate.body);
        }
      }

      // Recursively process nested blocks
      if (stmt.type === 'IfStatement') {
        if (stmt.consequent && stmt.consequent.type === 'BlockStatement') {
          restructureIfStatements(stmt.consequent.body);
        }
        if (stmt.alternate && stmt.alternate.type === 'BlockStatement') {
          restructureIfStatements(stmt.alternate.body);
        }
      } else if (stmt.type === 'ForStatement' && stmt.body && stmt.body.type === 'BlockStatement') {
        restructureIfStatements(stmt.body.body);
      } else if (stmt.type === 'BlockStatement') {
        restructureIfStatements(stmt.body);
      }
    }
  }

  restructureIfStatements(functionNode.body.body);

  // 3. Transform all return statements to assignments
  const transformReturns = {
    ReturnStatement(node) {
      // Convert return statement to assignment
      node.type = 'ExpressionStatement';
      node.expression = {
        type: 'AssignmentExpression',
        operator: '=',
        left: { type: 'Identifier', name: '__returnValue' },
        right: node.argument || { type: 'Identifier', name: 'undefined' }
      };
      delete node.argument;
    }
  };

  recursive(functionNode.body, {}, transformReturns);

  // 4. Add final return statement
  const finalReturn = {
    type: 'ReturnStatement',
    argument: { type: 'Identifier', name: '__returnValue' }
  };

  functionNode.body.body.push(finalReturn);
}

// Helper function to check if a function body contains .set() calls in control flow
function functionHasSetInControlFlow(functionNode) {
  let hasSetInControlFlow = false;
  let inControlFlow = 0;

  const checkForSetCalls = {
    IfStatement(node, state, c) {
      inControlFlow++;
      if (node.test) c(node.test, state);
      if (node.consequent) c(node.consequent, state);
      if (node.alternate) c(node.alternate, state);
      inControlFlow--;
    },
    ForStatement(node, state, c) {
      inControlFlow++;
      if (node.init) c(node.init, state);
      if (node.test) c(node.test, state);
      if (node.update) c(node.update, state);
      if (node.body) c(node.body, state);
      inControlFlow--;
    },
    CallExpression(node) {
      // Check if this is a .set() call
      if (inControlFlow > 0 &&
          node.callee?.type === 'MemberExpression' &&
          node.callee?.property?.name === 'set') {
        hasSetInControlFlow = true;
      }
    }
  };

  if (functionNode.body && functionNode.body.type === 'BlockStatement') {
    recursive(functionNode.body, {}, checkForSetCalls);
  }

  return hasSetInControlFlow;
}

// Transform a function to use __setValue pattern instead of .set() calls in branches/loops
function transformFunctionSetCalls(functionNode) {
  if (!functionNode.body || functionNode.body.type !== 'BlockStatement') {
    return; // Can't transform arrow functions with expression bodies
  }

  // Track which hooks have .set() calls, mapping expression string to the actual AST node
  const hooksWithSetCalls = new Map(); // exprString -> hookObjectNode

  // First pass: find all hooks that have .set() calls in control flow
  const findSetCalls = {
    CallExpression(node) {
      if (node.callee?.type === 'MemberExpression' &&
          node.callee?.property?.name === 'set' &&
          node.callee?.object) {
        // This is something like filterColor.set(...) or myp5.filterColor.set(...)
        const hookObjectNode = node.callee.object;
        const exprString = escodegen.generate(hookObjectNode);
        if (!hooksWithSetCalls.has(exprString)) {
          hooksWithSetCalls.set(exprString, hookObjectNode);
        }
      }
    }
  };

  recursive(functionNode.body, {}, findSetCalls);

  if (hooksWithSetCalls.size === 0) {
    return; // No .set() calls to transform
  }

  // For each hook with .set() calls, add intermediate variable and transform
  for (const [exprString, hookObjectNode] of hooksWithSetCalls) {
    // Create a safe variable name from the expression
    const safeVarName = exprString.replace(/[^a-zA-Z0-9_]/g, '_');
    const intermediateVarName = `__${safeVarName}_value`;

    // 1. Find the .begin() call and insert intermediate variable right after it
    const intermediateVarDecl = {
      type: 'VariableDeclaration',
      declarations: [{
        type: 'VariableDeclarator',
        id: { type: 'Identifier', name: intermediateVarName },
        init: null
      }],
      kind: 'let'
    };

    let beginCallIndex = -1;
    for (let i = 0; i < functionNode.body.body.length; i++) {
      const stmt = functionNode.body.body[i];
      if (stmt.type === 'ExpressionStatement' &&
          stmt.expression?.type === 'CallExpression' &&
          stmt.expression?.callee?.type === 'MemberExpression' &&
          stmt.expression?.callee?.property?.name === 'begin') {
        const beginExprString = escodegen.generate(stmt.expression.callee.object);
        if (beginExprString === exprString) {
          beginCallIndex = i;
          break;
        }
      }
    }

    // Insert intermediate variable after .begin() if found, otherwise at the start
    if (beginCallIndex !== -1) {
      functionNode.body.body.splice(beginCallIndex + 1, 0, intermediateVarDecl);
    } else {
      functionNode.body.body.unshift(intermediateVarDecl);
    }

    // 2. Transform all .set() calls to assignments
    const transformSetToAssignment = {
      CallExpression(node, state, ancestors) {
        // Check if this is a .set() call for this hook
        if (node.callee?.type === 'MemberExpression' &&
            node.callee?.property?.name === 'set' &&
            node.callee?.object) {
          const currentExprString = escodegen.generate(node.callee.object);
          if (currentExprString === exprString && node.arguments.length > 0) {
            // Find the parent statement
            let parentStmt = null;
            for (let i = ancestors.length - 1; i >= 0; i--) {
              if (ancestors[i].type === 'ExpressionStatement') {
                parentStmt = ancestors[i];
                break;
              }
            }

            if (parentStmt) {
              // Replace the .set() call with an assignment
              parentStmt.type = 'ExpressionStatement';
              parentStmt.expression = {
                type: 'AssignmentExpression',
                operator: '=',
                left: { type: 'Identifier', name: intermediateVarName },
                right: node.arguments[0]
              };
            }
          }
        }
      }
    };

    ancestor(functionNode.body, transformSetToAssignment);

    // 3. Find the .end() call and insert final .set() call right before it
    const finalSetCall = {
      type: 'ExpressionStatement',
      expression: {
        type: 'CallExpression',
        callee: {
          type: 'MemberExpression',
          object: JSON.parse(JSON.stringify(hookObjectNode)), // Deep copy the original node
          property: { type: 'Identifier', name: 'set' },
          computed: false
        },
        arguments: [{ type: 'Identifier', name: intermediateVarName }]
      }
    };

    // Find the .end() call for this hook
    let endCallIndex = -1;
    for (let i = 0; i < functionNode.body.body.length; i++) {
      const stmt = functionNode.body.body[i];
      if (stmt.type === 'ExpressionStatement' &&
          stmt.expression?.type === 'CallExpression' &&
          stmt.expression?.callee?.type === 'MemberExpression' &&
          stmt.expression?.callee?.property?.name === 'end') {
        const endExprString = escodegen.generate(stmt.expression.callee.object);
        if (endExprString === exprString) {
          endCallIndex = i;
          break;
        }
      }
    }

    // Insert the final .set() call before .end() if found, otherwise at the end
    if (endCallIndex !== -1) {
      functionNode.body.body.splice(endCallIndex, 0, finalSetCall);
    } else {
      // If no .end() found, insert before return statement or at the end
      const lastStatement = functionNode.body.body[functionNode.body.body.length - 1];
      if (lastStatement && lastStatement.type === 'ReturnStatement') {
        functionNode.body.body.splice(functionNode.body.body.length - 1, 0, finalSetCall);
      } else {
        functionNode.body.body.push(finalSetCall);
      }
    }
  }
}

// Main transformation pass: find and transform functions with .set() calls in control flow
function transformSetCallsInControlFlow(ast, names) {
  const functionsToTransform = [];

  // Collect functions that have .set() calls in control flow
  const collectFunctions = {
    ArrowFunctionExpression(node, ancestors) {
      if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, names))) {
        return;
      }
      if (functionHasSetInControlFlow(node)) {
        functionsToTransform.push(node);
      }
    },
    FunctionExpression(node, ancestors) {
      if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, names))) {
        return;
      }
      if (functionHasSetInControlFlow(node)) {
        functionsToTransform.push(node);
      }
    },
    FunctionDeclaration(node, ancestors) {
      if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, names))) {
        return;
      }
      if (functionHasSetInControlFlow(node)) {
        functionsToTransform.push(node);
      }
    }
  };

  ancestor(ast, collectFunctions);

  // Transform each collected function
  for (const funcNode of functionsToTransform) {
    transformFunctionSetCalls(funcNode);
  }
}

// Main transformation pass: find and transform helper functions with early returns
function transformHelperFunctionEarlyReturns(ast, names) {
  const helperFunctionsToTransform = [];

  // Collect helper functions that need transformation
  const collectHelperFunctions = {
    VariableDeclarator(node, ancestors) {
      if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, names))) {
        return;
      }
      const init = node.init;
      if (init && (init.type === 'ArrowFunctionExpression' || init.type === 'FunctionExpression')) {
        if (functionHasEarlyReturns(init)) {
          helperFunctionsToTransform.push(init);
        }
      }
    },
    FunctionDeclaration(node, ancestors) {
      if (ancestors.some(a => nodeIsUniform(a) || nodeIsUniformCallbackFn(a, names))) {
        return;
      }
      if (functionHasEarlyReturns(node)) {
        helperFunctionsToTransform.push(node);
      }
    },
    // Don't transform functions that are direct arguments to call expressions
    CallExpression(node, ancestors) {
      // Arguments to CallExpressions are base callbacks, not helpers
      // We skip them by not adding them to the transformation list
    }
  };

  ancestor(ast, collectHelperFunctions);

  // Transform each collected helper function
  for (const funcNode of helperFunctionsToTransform) {
    transformHelperFunction(funcNode);
  }
}

/**
 * @private
 * @internal
 *
 * Transpiles a p5.strands callback into executable JavaScript by applying
 * a multi-pass AST transformation pipeline.
 *
 * Pipeline stages:
 *
 * 1. Collect uniform callback names
 *    - Identifies functions passed into uniform() so they are excluded from transformation
 *
 * 2. transformSetCallsInControlFlow
 *    - Rewrites `.set()` calls inside control flow into intermediate variable assignments
 *
 * 3. Non-control-flow transformations
 *    - Applies ASTCallbacks to transform expressions, assignments, etc.
 *    - Skips IfStatement and ForStatement (handled later)
 *
 * 4. transformHelperFunctionEarlyReturns
 *    - Converts early returns in helper functions into a single return value pattern
 *
 * 5. Control flow transformation (post-order)
 *    - Transforms IfStatement → __p5.strandsIf
 *    - Transforms ForStatement → __p5.strandsFor
 *    - Handles variable propagation across branches/loops
 *
 * This staged approach ensures correct ordering and avoids transformation conflicts.
 */

// Wraps each callback with a uniform context guard, eliminating the need
// to repeat the early-return check at the top of every handler.
function makeGuardedCallbacks(callbacks) {
  const guarded = {};
  for (const [name, fn] of Object.entries(callbacks)) {
    guarded[name] = (node, state, ancestors) => {
      if (ancestors.some(a =>
        nodeIsUniform(a) ||
        nodeIsUniformCallbackFn(a, state.uniformCallbackNames)
      )) return;
      return fn(node, state, ancestors);
    };
  }
  return guarded;
}

function runNonControlFlowPass(
  ast,
  uniformCallbackNames,
  initialShaderNameState
) {
  const nonControlFlowCallbacks = { ...ASTCallbacks };
  delete nonControlFlowCallbacks.IfStatement;
  delete nonControlFlowCallbacks.ForStatement;
  const state = {
    varyings: {},
    uniformCallbackNames,
    shaderNameMap: createStrandsShaderNameMap(),
    shaderNameState: createStrandsShaderNameState(
      initialShaderNameState?.nextSuffix || 0
    )
  };
  ancestor(ast, nonControlFlowCallbacks, undefined, state);
  return {
    shaderNameMap: state.shaderNameMap,
    shaderNameState: state.shaderNameState
  };
}

function runControlFlowPass(ast, uniformCallbackNames) {
  const postOrderControlFlowTransform = {
    CallExpression(node, state, c) {
      if (nodeIsUniform(node)) { return; }
      if (node.callee) c(node.callee, state);
      for (const arg of node.arguments) c(arg, state);
    },
    FunctionDeclaration(node, state, c) {
      if (state.uniformCallbackNames?.has(node.id?.name)) return;
      if (node.body) c(node.body, state);
    },
    VariableDeclarator(node, state, c) {
      if (
        state.uniformCallbackNames?.has(node.id?.name) &&
        (node.init?.type === 'FunctionExpression' || node.init?.type === 'ArrowFunctionExpression')
      ) { return; }
      if (node.init) c(node.init, state);
    },
    IfStatement(node, state, c) {
      state.inControlFlow++;
      if (node.test) c(node.test, state);
      if (node.consequent) c(node.consequent, state);
      if (node.alternate) c(node.alternate, state);
      ASTCallbacks.IfStatement(node, state, []);
      state.inControlFlow--;
    },
    ForStatement(node, state, c) {
      state.inControlFlow++;
      if (node.init) c(node.init, state);
      if (node.test) c(node.test, state);
      if (node.update) c(node.update, state);
      if (node.body) c(node.body, state);
      ASTCallbacks.ForStatement(node, state, []);
      state.inControlFlow--;
    },
    ReturnStatement(node, state, c) {
      if (!state.inControlFlow) return;
      node.type = 'ExpressionStatement';
      node.expression = {
        type: 'CallExpression',
        callee: { type: 'Identifier', name: '__p5.strandsEarlyReturn' },
        arguments: node.argument ? [node.argument] : []
      };
      delete node.argument;
    }
  };
  recursive(ast, { varyings: {}, inControlFlow: 0, uniformCallbackNames }, postOrderControlFlowTransform);
}

function buildStrandsCallback(p5, ast, scope) {
  const transpiledSource = escodegen.generate(ast);
  const scopeKeys = Object.keys(scope);
  const match = /\(?\s*(?:function)?\s*\w*\s*\(([^)]*)\)\s*(?:=>)?\s*{((?:.|\n)*)}\s*;?\s*\)?/
    .exec(transpiledSource);
  if (!match) {
    console.log(transpiledSource);
    throw new Error('Could not parse p5.strands function!');
  }
  const params = match[1].split(/,\s*/).filter(param => !!param.trim());
  let paramVals, paramNames;
  if (params.length > 0) {
    paramNames = params;
    paramVals = [scope];
  } else {
    paramNames = scopeKeys;
    paramVals = scopeKeys.map(key => scope[key]);
  }
  const body = match[2];
  try {
    const internalStrandsCallback = new Function('__p5', ...paramNames, body);
    // Create a parameter called __p5, not just p5, because users of instance mode
    // may pass in a variable called p5 as a scope variable. If we rely on a variable called
    // p5, then the scope variable called p5 might accidentally override internal function
    // calls to p5 static methods.
    return () => internalStrandsCallback(p5, ...paramVals);
  } catch (e) {
    console.error(e);
    console.log(paramNames);
    console.log(body);
    throw new Error('Error transpiling p5.strands callback!');
  }
}



export function transpileStrandsToJS(
  p5,
  sourceString,
  srcLocations,
  scope,
  initialShaderNameState
) {
  blockVarCounter = 0;
  loopVarCounter = 0;

  const ast = parse(sourceString, {
    ecmaVersion: 2021,
    locations: srcLocations
  });

  throwIfLoopProtectionInserted(ast);

  // Pre-pass: collect names of functions passed by reference as uniform callbacks
  const uniformCallbackNames = collectUniformCallbackNames(ast);

  // Pass 1: transform .set() calls in control flow to use intermediate variables
  transformSetCallsInControlFlow(ast, uniformCallbackNames);

  // Pass 2: transform non-control-flow nodes (operators, varyings, uniforms, arrays)
  const { shaderNameMap, shaderNameState } = runNonControlFlowPass(
    ast,
    uniformCallbackNames,
    initialShaderNameState
  );

  // Pass 3: transform helper functions with early returns to use __returnValue pattern
  transformHelperFunctionEarlyReturns(ast, uniformCallbackNames);

  // Pass 4: transform if/for statements post-order into strandsIf/strandsFor calls
  runControlFlowPass(ast, uniformCallbackNames);

  const callback = buildStrandsCallback(p5, ast, scope);
  return {
    callback,
    shaderNameMap,
    shaderNameState
  };
}
