import {
  createContext,
  createMemo,
  createSignal,
  onCleanup,
  useContext,
  type Accessor,
  type ParentProps,
  For,
  Show,
} from "solid-js";
import { useKeyboard, useTerminalDimensions } from "@opentui/solid";
import { KeybindsResolved, useKeybinds } from "../context/KeybindContext";
import { useDialog } from "./dialog";
import { useTheme } from "../context/ThemeContext";
import { TextAttributes } from "@opentui/core";
import { emit } from "../utils/event-bus";
import { SelectableBox, SelectableText } from "@/components/Selectable";

/**
 * Command option for the command palette.
 */
export type CommandOption = {
  /** Display title */
  title: string;
  /** Unique identifier */
  value: string;
  /** Description shown below title */
  description?: string;
  /** Category for grouping */
  category?: string;
  /** Keybind reference */
  keybind?: keyof KeybindsResolved;
  /** Whether this command is suggested */
  suggested?: boolean;
  /** Slash command configuration */
  slash?: {
    name: string;
    aliases?: string[];
  };
  /** Whether to hide from command list */
  hidden?: boolean;
  /** Whether command is enabled */
  enabled?: boolean;
  /** Footer text (usually keybind display) */
  footer?: string;
  /** Handler when command is selected */
  onSelect?: (dialog: ReturnType<typeof useDialog>) => void;
};

type CommandContext = ReturnType<typeof init>;
const ctx = createContext<CommandContext>();

function init() {
  const [registrations, setRegistrations] = createSignal<
    Accessor<CommandOption[]>[]
  >([]);
  const [suspendCount, setSuspendCount] = createSignal(0);
  const dialog = useDialog();
  const keybind = useKeybinds();

  const entries = createMemo(() => {
    const all = registrations().flatMap((x) => x());
    return all.map((x) => ({
      ...x,
      footer: x.keybind ? keybind.print(x.keybind) : undefined,
    }));
  });

  const isEnabled = (option: CommandOption) => option.enabled !== false;
  const isVisible = (option: CommandOption) =>
    isEnabled(option) && !option.hidden;

  const visibleOptions = createMemo(() =>
    entries().filter((option) => isVisible(option)),
  );
  const suggestedOptions = createMemo(() =>
    visibleOptions()
      .filter((option) => option.suggested)
      .map((option) => ({
        ...option,
        value: `suggested:${option.value}`,
        category: "Suggested",
      })),
  );
  const suspended = () => suspendCount() > 0;

  // Handle keybind shortcuts
  useKeyboard((evt) => {
    if (suspended()) return;
    if (dialog.isOpen) return;
    for (const option of entries()) {
      if (!isEnabled(option)) continue;
      if (option.keybind && keybind.match(option.keybind, evt)) {
        evt.preventDefault();
        option.onSelect?.(dialog);
        emit("command.execute", { command: option.value });
        return;
      }
    }
  });

  const result = {
    /**
     * Trigger a command by its value.
     */
    trigger(name: string) {
      for (const option of entries()) {
        if (option.value === name) {
          if (!isEnabled(option)) return;
          option.onSelect?.(dialog);
          emit("command.execute", { command: name });
          return;
        }
      }
    },
    /**
     * Get all slash commands.
     */
    slashes() {
      return visibleOptions().flatMap((option) => {
        const slash = option.slash;
        if (!slash) return [];
        return {
          display: "/" + slash.name,
          description: option.description ?? option.title,
          aliases: slash.aliases?.map((alias) => "/" + alias),
          onSelect: () => result.trigger(option.value),
        };
      });
    },
    /**
     * Enable/disable keybinds temporarily.
     */
    keybinds(enabled: boolean) {
      setSuspendCount((count) => count + (enabled ? -1 : 1));
    },
    suspended,
    /**
     * Show the command palette dialog.
     */
    show() {
      dialog.replace(() => (
        <CommandDialog
          options={visibleOptions()}
          suggestedOptions={suggestedOptions()}
        />
      ));
    },
    /**
     * Register commands. Returns cleanup function.
     */
    register(cb: () => CommandOption[]) {
      const results = createMemo(cb);
      setRegistrations((arr) => [results, ...arr]);
      onCleanup(() => {
        setRegistrations((arr) => arr.filter((x) => x !== results));
      });
    },
    /**
     * Get all visible options.
     */
    get options() {
      return visibleOptions();
    },
  };
  return result;
}

export function useCommandDialog() {
  const value = useContext(ctx);
  if (!value) {
    throw new Error("useCommandDialog must be used within a CommandProvider");
  }
  return value;
}

export function CommandProvider(props: ParentProps) {
  const value = init();
  const dialog = useDialog();
  const keybind = useKeybinds();

  // Open command palette on ctrl+p or command_list keybind
  useKeyboard((evt) => {
    if (value.suspended()) return;
    if (dialog.isOpen) return;
    if (evt.defaultPrevented) return;
    if (keybind.match("command_list", evt)) {
      evt.preventDefault();
      value.show();
      return;
    }
  });

  return <ctx.Provider value={value}>{props.children}</ctx.Provider>;
}

/**
 * Command palette dialog component.
 */
function CommandDialog(props: {
  options: CommandOption[];
  suggestedOptions: CommandOption[];
}) {
  const { theme } = useTheme();
  const dialog = useDialog();
  const dimensions = useTerminalDimensions();
  const [filter, setFilter] = createSignal("");
  const [selectedIndex, setSelectedIndex] = createSignal(0);

  const filteredOptions = createMemo(() => {
    const query = filter().toLowerCase();
    if (!query) {
      return [...props.suggestedOptions, ...props.options];
    }
    return props.options.filter(
      (option) =>
        option.title.toLowerCase().includes(query) ||
        option.description?.toLowerCase().includes(query) ||
        option.category?.toLowerCase().includes(query),
    );
  });

  // Reset selection when filter changes
  createMemo(() => {
    filter();
    setSelectedIndex(0);
  });

  useKeyboard((evt) => {
    if (evt.name === "escape") {
      dialog.clear();
      evt.preventDefault();
      return;
    }

    if (evt.name === "return" || evt.name === "enter") {
      const option = filteredOptions()[selectedIndex()];
      if (option) {
        option.onSelect?.(dialog);
        dialog.clear();
      }
      evt.preventDefault();
      return;
    }

    if (evt.name === "up" || (evt.ctrl && evt.name === "p")) {
      setSelectedIndex((i) => Math.max(0, i - 1));
      evt.preventDefault();
      return;
    }

    if (evt.name === "down" || (evt.ctrl && evt.name === "n")) {
      setSelectedIndex((i) => Math.min(filteredOptions().length - 1, i + 1));
      evt.preventDefault();
      return;
    }

    // Handle text input
    if (evt.name && evt.name.length === 1 && !evt.ctrl && !evt.meta) {
      setFilter((f) => f + evt.name);
      return;
    }

    if (evt.name === "backspace") {
      setFilter((f) => f.slice(0, -1));
      return;
    }
  });

  const maxHeight = Math.floor(dimensions().height * 0.6);

  return (
    <box flexDirection="column" padding={1} borderColor={theme.border}>
      {/* Search input */}
      <box marginBottom={1}>
        <text fg={theme.textMuted}>{"> "}</text>
        <text fg={theme.text}>{filter() || "Type to search commands..."}</text>
      </box>

      {/* Command list */}
      <box flexDirection="column" maxHeight={maxHeight} borderColor={theme.border}>
        <For each={filteredOptions().slice(0, 10)}>
          {(option, index) => (
            <SelectableBox
              selected={() => index() === selectedIndex()}
              flexDirection="column"
              padding={1}
              onMouseDown={() => {
                setSelectedIndex(index());
                const selectedOption = filteredOptions()[index()];
                if (selectedOption) {
                  selectedOption.onSelect?.(dialog);
                  dialog.clear();
                }
              }}
            >
               <box flexDirection="column" flexGrow={1}>
                 <SelectableText
                   selected={() => index() === selectedIndex()}
                   primary
                 >
                   {option.title}
                 </SelectableText>
                 <Show when={option.footer}>
                   <SelectableText
                     selected={() => index() === selectedIndex()}
                     tertiary
                   >
                     {option.footer}
                   </SelectableText>
                 </Show>
                 <Show when={option.description}>
                   <SelectableText
                     selected={() => index() === selectedIndex()}
                     tertiary
                   >
                     {option.description}
                   </SelectableText>
                 </Show>
               </box>
            </SelectableBox>
          )}
        </For>
        <Show when={filteredOptions().length === 0}>
          <text fg={theme.textMuted} style={{ padding: 1 }}>
            No commands found
          </text>
        </Show>
      </box>
    </box>
  );
}