"use client";

import { ChevronDownIcon, ChevronLeftIcon, ChevronRightIcon } from "lucide-react";
import * as React from "react";
import { type DayButton, DayPicker, getDefaultClassNames } from "react-day-picker";

import { buttonVariantClassNames } from "@/components/ui/button";
import { cn } from "@/lib/utils";

const defaultClassNames = getDefaultClassNames();

type CalendarComponents = NonNullable<React.ComponentProps<typeof DayPicker>["components"]>;

type CalendarButtonVariant = "ghost" | "outline";

function calendarButtonClassName(variant: CalendarButtonVariant) {
  return cn(
    "inline-flex items-center justify-center rounded-md text-sm outline-none transition-colors focus-visible:ring-2 focus-visible:ring-[var(--button-focus-ring)] disabled:pointer-events-none disabled:opacity-40",
    buttonVariantClassNames[variant]
  );
}

function Calendar({
  className,
  classNames,
  showOutsideDays = true,
  captionLayout = "label",
  buttonVariant = "ghost",
  locale,
  formatters,
  components,
  ...props
}: React.ComponentProps<typeof DayPicker> & {
  buttonVariant?: CalendarButtonVariant;
}) {
  const mergedComponents = React.useMemo(
    () => ({ ...DEFAULT_COMPONENTS, ...components }),
    [components]
  );

  return (
    <DayPicker
      animate
      showOutsideDays={showOutsideDays}
      className={cn(
        "group/calendar bg-transparent p-2 text-primary [--cell-radius:8px] [--cell-size:32px]",
        className
      )}
      captionLayout={captionLayout}
      locale={locale}
      formatters={{
        formatMonthDropdown: (date) => date.toLocaleString(locale?.code, { month: "short" }),
        ...formatters,
      }}
      classNames={{
        root: cn("w-fit", defaultClassNames.root),
        months: cn("relative flex flex-col gap-4 md:flex-row", defaultClassNames.months),
        month: cn("flex w-full flex-col gap-4", defaultClassNames.month),
        nav: cn(
          "absolute inset-x-0 top-0 flex w-full items-center justify-between gap-1 px-1 pt-1",
          defaultClassNames.nav
        ),
        button_previous: cn(
          calendarButtonClassName(buttonVariant),
          "size-(--cell-size) p-0 select-none aria-disabled:opacity-50",
          defaultClassNames.button_previous
        ),
        button_next: cn(
          calendarButtonClassName(buttonVariant),
          "size-(--cell-size) p-0 select-none aria-disabled:opacity-50",
          defaultClassNames.button_next
        ),
        month_caption: cn(
          "mb-1 flex h-(--cell-size) w-full items-center justify-center px-(--cell-size) pt-1",
          defaultClassNames.month_caption
        ),
        dropdowns: cn(
          "flex h-(--cell-size) w-full items-center justify-center gap-1.5 text-sm font-medium",
          defaultClassNames.dropdowns
        ),
        dropdown_root: cn(
          "cn-calendar-dropdown-root relative rounded-(--cell-radius)",
          defaultClassNames.dropdown_root
        ),
        dropdown: cn("absolute inset-0 bg-popover opacity-0", defaultClassNames.dropdown),
        caption_label: cn(
          "font-medium text-primary select-none",
          captionLayout === "label"
            ? "cn-calendar-caption text-sm"
            : "cn-calendar-caption-label flex items-center gap-1 rounded-(--cell-radius) text-sm [&>svg]:size-3.5 [&>svg]:text-tertiary",
          defaultClassNames.caption_label
        ),
        month_grid: cn("w-full border-collapse", defaultClassNames.month_grid),
        weekdays: cn("flex", defaultClassNames.weekdays),
        weekday: cn(
          "flex-1 rounded-(--cell-radius) text-xs font-normal text-tertiary select-none",
          defaultClassNames.weekday
        ),
        week: cn("mt-2 flex w-full", defaultClassNames.week),
        week_number_header: cn("w-(--cell-size) select-none", defaultClassNames.week_number_header),
        week_number: cn("text-xs text-tertiary select-none", defaultClassNames.week_number),
        day: cn(
          "group/day relative aspect-square h-full w-full rounded-(--cell-radius) p-0 text-center select-none [&:last-child[data-selected=true]_button]:rounded-r-(--cell-radius)",
          props.showWeekNumber
            ? "[&:nth-child(2)[data-selected=true]_button]:rounded-l-(--cell-radius)"
            : "[&:first-child[data-selected=true]_button]:rounded-l-(--cell-radius)",
          defaultClassNames.day
        ),
        range_start: cn(
          "relative isolate z-0 rounded-l-(--cell-radius) bg-fill after:absolute after:inset-y-0 after:right-0 after:w-4 after:bg-fill",
          defaultClassNames.range_start
        ),
        range_middle: cn("rounded-none", defaultClassNames.range_middle),
        range_end: cn(
          "relative isolate z-0 rounded-r-(--cell-radius) bg-fill after:absolute after:inset-y-0 after:left-0 after:w-4 after:bg-fill",
          defaultClassNames.range_end
        ),
        today: cn(
          "rounded-(--cell-radius) bg-fill text-primary data-[selected=true]:rounded-none",
          defaultClassNames.today
        ),
        outside: cn("text-muted aria-selected:text-muted", defaultClassNames.outside),
        disabled: cn("text-muted opacity-40", defaultClassNames.disabled),
        hidden: cn("invisible", defaultClassNames.hidden),
        ...classNames,
      }}
      components={mergedComponents}
      {...props}
    />
  );
}

function CalendarRoot({
  className,
  rootRef,
  ...props
}: Parameters<CalendarComponents["Root"] & {}>[0]) {
  return <div data-slot="calendar" ref={rootRef} className={cn(className)} {...props} />;
}

function CalendarChevron({
  className,
  orientation,
  ...props
}: Parameters<CalendarComponents["Chevron"] & {}>[0]) {
  if (orientation === "left") {
    return <ChevronLeftIcon className={cn("size-4", className)} {...props} />;
  }

  if (orientation === "right") {
    return <ChevronRightIcon className={cn("size-4", className)} {...props} />;
  }

  return <ChevronDownIcon className={cn("size-4", className)} {...props} />;
}

function CalendarWeekNumber({
  children,
  ...props
}: Parameters<CalendarComponents["WeekNumber"] & {}>[0]) {
  return (
    <td {...props}>
      <div className="flex size-(--cell-size) items-center justify-center text-center">
        {children}
      </div>
    </td>
  );
}

function CalendarDayButton({
  className,
  day,
  modifiers,
  ...props
}: React.ComponentProps<typeof DayButton>) {
  const ref = React.useRef<HTMLButtonElement>(null);
  React.useEffect(() => {
    if (modifiers.focused) ref.current?.focus();
  }, [modifiers.focused]);

  return (
    <button
      type="button"
      data-day={day.date.toDateString()}
      data-selected-single={
        modifiers.selected &&
        !modifiers.range_start &&
        !modifiers.range_end &&
        !modifiers.range_middle
      }
      data-range-start={modifiers.range_start}
      data-range-end={modifiers.range_end}
      data-range-middle={modifiers.range_middle}
      className={cn(
        "relative isolate z-10 flex aspect-square size-auto w-full min-w-(--cell-size) flex-col items-center justify-center gap-1 border-0 text-sm text-secondary leading-none font-normal outline-none hover:bg-fill-subtle hover:text-primary group-data-[focused=true]/day:relative group-data-[focused=true]/day:z-10 group-data-[focused=true]/day:ring-2 group-data-[focused=true]/day:ring-[var(--input-focus-ring)] data-[range-end=true]:rounded-(--cell-radius) data-[range-end=true]:rounded-r-(--cell-radius) data-[range-end=true]:bg-primary data-[range-end=true]:text-on-primary data-[range-middle=true]:rounded-none data-[range-middle=true]:bg-fill data-[range-middle=true]:text-primary data-[range-start=true]:rounded-(--cell-radius) data-[range-start=true]:rounded-l-(--cell-radius) data-[range-start=true]:bg-primary data-[range-start=true]:text-on-primary data-[selected-single=true]:bg-primary data-[selected-single=true]:text-on-primary data-[selected-single=true]:hover:bg-primary data-[selected-single=true]:hover:text-on-primary [&>span]:text-xs [&>span]:opacity-70",
        defaultClassNames.day,
        className
      )}
      {...props}
    />
  );
}

const DEFAULT_COMPONENTS = {
  Root: CalendarRoot,
  Chevron: CalendarChevron,
  DayButton: CalendarDayButton,
  WeekNumber: CalendarWeekNumber,
} satisfies Partial<CalendarComponents>;

export { Calendar, CalendarDayButton };
