import { Check, ChevronsUpDown } from "lucide-react";
import { useMemo, useRef, useState, type ReactNode } from "react";
import { Button } from "@/components/ui/button";
import {
  Command,
  CommandEmpty,
  CommandGroup,
  CommandInput,
  CommandItem,
  CommandList,
} from "@/components/ui/command";
import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
import { fuzzyTextMatchesQuery, normalizeSearchText, scoreFuzzyTextFields } from "@/lib/searchable-select";
import { cn } from "@/lib/utils";

export interface SearchableSelectOption<TValue extends string = string> {
  key: string;
  value: TValue;
  label: string;
  title?: string;
  searchText?: string;
  disabled?: boolean;
}

export interface SearchableSelectGroup<TValue extends string = string, TOption extends SearchableSelectOption<TValue> = SearchableSelectOption<TValue>> {
  id: string;
  label?: string;
  options: readonly TOption[];
}

interface SearchableSelectRenderState {
  selected: boolean;
}

export interface SearchableSelectProps<
  TValue extends string = string,
  TOption extends SearchableSelectOption<TValue> = SearchableSelectOption<TValue>,
> {
  value: TValue | "";
  groups: readonly SearchableSelectGroup<TValue, TOption>[];
  onValueChange: (value: TValue, option: TOption) => void | boolean | { close?: boolean };
  placeholder: string;
  searchPlaceholder?: string;
  emptyMessage?: string;
  loadingMessage?: string;
  loading?: boolean;
  disabled?: boolean;
  className?: string;
  triggerClassName?: string;
  contentClassName?: string;
  align?: "start" | "center" | "end";
  contentWidth?: "trigger" | "auto";
  renderValue?: (option: TOption | null) => ReactNode;
  renderOption?: (option: TOption, state: SearchableSelectRenderState) => ReactNode;
  deriveGroups?: (
    query: string,
    groups: readonly SearchableSelectGroup<TValue, TOption>[],
  ) => readonly SearchableSelectGroup<TValue, TOption>[];
  filterOption?: (option: TOption, query: string) => boolean;
  scoreOption?: (option: TOption, query: string) => number | null;
  disablePortal?: boolean;
  /**
   * Optional pinned "creatable" item rendered at the bottom of the list,
   * regardless of the query (used e.g. by the secret picker's
   * `+ Create secret "<query>"…` affordance). `render` receives the live
   * query so the label can echo it; `onSelect` fires with the query and the
   * popover closes.
   */
  createItem?: {
    render: (query: string) => ReactNode;
    onSelect: (query: string) => void;
  };
}

function defaultFilterOption(option: SearchableSelectOption, query: string) {
  return fuzzyTextMatchesQuery(`${option.label} ${option.searchText ?? ""}`, query);
}

function defaultScoreOption(option: SearchableSelectOption, query: string) {
  return scoreFuzzyTextFields([
    { text: option.label, weight: 0 },
    { text: option.searchText, weight: 20 },
  ], query);
}

export function SearchableSelect<
  TValue extends string = string,
  TOption extends SearchableSelectOption<TValue> = SearchableSelectOption<TValue>,
>({
  value,
  groups,
  onValueChange,
  placeholder,
  searchPlaceholder = "Search...",
  emptyMessage = "No options found.",
  loadingMessage = "Loading...",
  loading = false,
  disabled = false,
  className,
  triggerClassName,
  contentClassName,
  align = "start",
  contentWidth = "trigger",
  renderValue,
  renderOption,
  deriveGroups,
  filterOption = defaultFilterOption,
  scoreOption,
  disablePortal,
  createItem,
}: SearchableSelectProps<TValue, TOption>) {
  const [open, setOpen] = useState(false);
  const [query, setQuery] = useState("");
  const pointerFocusRef = useRef(false);
  const suppressNextTriggerFocusRef = useRef(false);

  const selectedOption = useMemo(() => {
    for (const group of groups) {
      const option = group.options.find((candidate) => candidate.value === value);
      if (option) return option;
    }
    return null;
  }, [groups, value]);

  const visibleGroups = useMemo(
    () => (deriveGroups ? deriveGroups(query, groups) : groups),
    [deriveGroups, groups, query],
  );

  const filteredGroups = useMemo(() => {
    if (loading) return [];
    const normalizedQuery = normalizeSearchText(query);
    return visibleGroups
      .map((group) => {
        const options = group.options
          .map((option, index) => {
            if (!normalizedQuery) return { option, index, score: 0 };

            if (!filterOption(option, query)) return null;

            if (scoreOption) {
              const score = scoreOption(option, query);
              return score === null ? null : { option, index, score };
            }

            return {
              option,
              index,
              score: defaultScoreOption(option, query) ?? Number.MAX_SAFE_INTEGER,
            };
          })
          .filter((entry): entry is { option: TOption; index: number; score: number } => entry !== null);

        if (normalizedQuery) {
          options.sort((a, b) => a.score - b.score || a.index - b.index);
        }

        return {
          ...group,
          options: options.map((entry) => entry.option),
        };
      })
      .filter((group) => group.options.length > 0);
  }, [filterOption, loading, query, scoreOption, visibleGroups]);

  const hasOptions = filteredGroups.some((group) => group.options.length > 0);

  function closePopover({ suppressTriggerFocus = false }: { suppressTriggerFocus?: boolean } = {}) {
    if (suppressTriggerFocus) {
      suppressNextTriggerFocusRef.current = true;
    }
    setOpen(false);
    setQuery("");
  }

  function selectOption(option: TOption) {
    if (option.disabled) return;
    suppressNextTriggerFocusRef.current = true;
    const result = onValueChange(option.value, option);
    if (result === false || (typeof result === "object" && result?.close === false)) {
      return;
    }
    closePopover();
  }

  return (
    <Popover
      open={open}
      onOpenChange={(next) => {
        setOpen(next);
        if (!next) setQuery("");
      }}
    >
      <PopoverTrigger asChild>
        <Button
          type="button"
          variant="outline"
          disabled={disabled}
          onPointerDown={() => {
            pointerFocusRef.current = true;
          }}
          onFocus={() => {
            const shouldIgnoreFocus = pointerFocusRef.current || suppressNextTriggerFocusRef.current;
            pointerFocusRef.current = false;
            suppressNextTriggerFocusRef.current = false;
            if (shouldIgnoreFocus) {
              return;
            }
            setOpen(true);
          }}
          onKeyDown={(event) => {
            if (event.key === "Escape" && open) {
              event.preventDefault();
              closePopover();
            }
          }}
          aria-expanded={open}
          role="combobox"
          className={cn("w-full justify-between overflow-hidden", className, triggerClassName)}
        >
          <span className={cn("min-w-0 flex-1 truncate text-left", !selectedOption && "text-muted-foreground")}>
            {renderValue ? renderValue(selectedOption) : selectedOption?.label ?? placeholder}
          </span>
          <ChevronsUpDown className="ml-2 size-4 opacity-50" />
        </Button>
      </PopoverTrigger>
      <PopoverContent
        align={align}
        collisionPadding={16}
        disablePortal={disablePortal}
        className={cn(
          "p-0",
          contentWidth === "trigger"
            ? "w-(--radix-popover-trigger-width) min-w-56 max-w-(--sz-calc-23)"
            : "w-72 max-w-(--sz-calc-23)",
          contentClassName,
        )}
        onKeyDownCapture={(event) => {
          if (event.key === "Escape") {
            event.preventDefault();
            event.stopPropagation();
            closePopover({ suppressTriggerFocus: true });
          }
        }}
      >
        <Command shouldFilter={false}>
          <CommandInput
            value={query}
            onValueChange={setQuery}
            placeholder={searchPlaceholder}
          />
          <CommandList
            className="overscroll-contain touch-pan-y"
            onWheelCapture={(event) => {
              if (event.currentTarget.scrollHeight > event.currentTarget.clientHeight) {
                event.stopPropagation();
              }
            }}
          >
            {loading ? (
              <div className="px-3 py-6 text-center text-sm text-muted-foreground">{loadingMessage}</div>
            ) : (
              <>
                {!hasOptions && !createItem ? <CommandEmpty>{emptyMessage}</CommandEmpty> : null}
                {!hasOptions && createItem ? (
                  <div className="px-3 py-3 text-center text-xs text-muted-foreground">{emptyMessage}</div>
                ) : null}
                {filteredGroups.map((group) => (
                  <CommandGroup key={group.id} heading={group.label}>
                    {group.options.map((option) => {
                      const selected = option.value === value;
                      return (
                        <CommandItem
                          key={option.key}
                          value={option.key}
                          disabled={option.disabled}
                          onSelect={() => selectOption(option)}
                        >
                          {renderOption
                            ? renderOption(option, { selected })
                            : <span className="min-w-0 truncate">{option.label}</span>}
                          <Check className={cn("ml-auto size-4", selected ? "opacity-100" : "opacity-0")} />
                        </CommandItem>
                      );
                    })}
                  </CommandGroup>
                ))}
                {createItem ? (
                  <CommandGroup className="border-t border-border">
                    <CommandItem
                      value="__searchable_select_create__"
                      onSelect={() => {
                        const q = query;
                        suppressNextTriggerFocusRef.current = true;
                        closePopover();
                        // Defer to the next macrotask so this popover fully
                        // closes (and Radix returns focus to the trigger)
                        // before the consumer opens its own popover. Firing
                        // synchronously lets the close's focus-return land as a
                        // `focusOutside` on the newly-opened popover, which
                        // Radix would immediately dismiss (see PAP-12476).
                        window.setTimeout(() => createItem.onSelect(q), 0);
                      }}
                    >
                      {createItem.render(query)}
                    </CommandItem>
                  </CommandGroup>
                ) : null}
              </>
            )}
          </CommandList>
        </Command>
      </PopoverContent>
    </Popover>
  );
}