import { type } from "@tauri-apps/plugin-os";
import { debounce } from "@yaakapp-internal/lib";
import { settingsAtom } from "@yaakapp-internal/models";
import { atom, useAtomValue } from "jotai";
import { useEffect } from "react";
import { capitalize } from "../lib/capitalize";
import { jotaiStore } from "../lib/jotai";

const HOLD_KEYS = ["Shift", "Control", "Command", "Alt", "Meta"];
const SINGLE_WHITELIST = ["Delete", "Enter", "Backspace"];

export type HotkeyAction =
  | "app.zoom_in"
  | "app.zoom_out"
  | "app.zoom_reset"
  | "command_palette.toggle"
  | "editor.autocomplete"
  | "environment_editor.toggle"
  | "hotkeys.showHelp"
  | "model.create"
  | "model.duplicate"
  | "request.send"
  | "request.rename"
  | "switcher.next"
  | "switcher.prev"
  | "switcher.toggle"
  | "settings.show"
  | "sidebar.filter"
  | "sidebar.selected.delete"
  | "sidebar.selected.duplicate"
  | "sidebar.selected.move"
  | "sidebar.selected.rename"
  | "sidebar.expand_all"
  | "sidebar.collapse_all"
  | "sidebar.focus"
  | "sidebar.context_menu"
  | "url_bar.focus"
  | "workspace_settings.show";

/** Default hotkeys for macOS (uses Meta for Cmd) */
const defaultHotkeysMac: Record<HotkeyAction, string[]> = {
  "app.zoom_in": ["Meta+Equal"],
  "app.zoom_out": ["Meta+Minus"],
  "app.zoom_reset": ["Meta+0"],
  "command_palette.toggle": ["Meta+k"],
  "editor.autocomplete": ["Control+Space"],
  "environment_editor.toggle": ["Meta+Shift+e"],
  "request.rename": ["Control+Shift+r"],
  "request.send": ["Meta+Enter", "Meta+r"],
  "hotkeys.showHelp": ["Meta+Shift+/"],
  "model.create": ["Meta+n"],
  "model.duplicate": ["Meta+d"],
  "switcher.next": ["Control+Shift+Tab"],
  "switcher.prev": ["Control+Tab"],
  "switcher.toggle": ["Meta+p"],
  "settings.show": ["Meta+,"],
  "sidebar.filter": ["Meta+f"],
  "sidebar.expand_all": ["Meta+Shift+Equal"],
  "sidebar.collapse_all": ["Meta+Shift+Minus"],
  "sidebar.selected.delete": ["Delete", "Meta+Backspace"],
  "sidebar.selected.duplicate": ["Meta+d"],
  "sidebar.selected.move": [],
  "sidebar.selected.rename": ["Enter"],
  "sidebar.focus": ["Meta+b"],
  "sidebar.context_menu": ["Control+Enter"],
  "url_bar.focus": ["Meta+l"],
  "workspace_settings.show": ["Meta+;"],
};

/** Default hotkeys for Windows/Linux (uses Control for Ctrl) */
const defaultHotkeysOther: Record<HotkeyAction, string[]> = {
  "app.zoom_in": ["Control+Equal"],
  "app.zoom_out": ["Control+Minus"],
  "app.zoom_reset": ["Control+0"],
  "command_palette.toggle": ["Control+k"],
  "editor.autocomplete": ["Control+Space"],
  "environment_editor.toggle": ["Control+Shift+e"],
  "request.rename": ["F2"],
  "request.send": ["Control+Enter", "Control+r"],
  "hotkeys.showHelp": ["Control+Shift+/"],
  "model.create": ["Control+n"],
  "model.duplicate": ["Control+d"],
  "switcher.next": ["Control+Shift+Tab"],
  "switcher.prev": ["Control+Tab"],
  "switcher.toggle": ["Control+p"],
  "settings.show": ["Control+,"],
  "sidebar.filter": ["Control+f"],
  "sidebar.expand_all": ["Control+Shift+Equal"],
  "sidebar.collapse_all": ["Control+Shift+Minus"],
  "sidebar.selected.delete": ["Delete", "Control+Backspace"],
  "sidebar.selected.duplicate": ["Control+d"],
  "sidebar.selected.move": [],
  "sidebar.selected.rename": ["Enter"],
  "sidebar.focus": ["Control+b"],
  "sidebar.context_menu": ["Alt+Insert"],
  "url_bar.focus": ["Control+l"],
  "workspace_settings.show": ["Control+;"],
};

/** Get the default hotkeys for the current platform */
export const defaultHotkeys: Record<HotkeyAction, string[]> =
  type() === "macos" ? defaultHotkeysMac : defaultHotkeysOther;

/** Atom that provides the effective hotkeys by merging defaults with user settings */
export const hotkeysAtom = atom((get) => {
  const settings = get(settingsAtom);
  const customHotkeys = settings?.hotkeys ?? {};

  // Merge default hotkeys with custom hotkeys from settings
  // Custom hotkeys override defaults for the same action
  // An empty array means the hotkey is intentionally disabled
  const merged: Record<HotkeyAction, string[]> = { ...defaultHotkeys };
  for (const [action, keys] of Object.entries(customHotkeys)) {
    if (action in defaultHotkeys && Array.isArray(keys)) {
      merged[action as HotkeyAction] = keys;
    }
  }
  return merged;
});

/** Helper function to get current hotkeys from the store */
function getHotkeys(): Record<HotkeyAction, string[]> {
  return jotaiStore.get(hotkeysAtom);
}

const hotkeyLabels: Record<HotkeyAction, string> = {
  "app.zoom_in": "Zoom In",
  "app.zoom_out": "Zoom Out",
  "app.zoom_reset": "Zoom to Actual Size",
  "command_palette.toggle": "Toggle Command Palette",
  "editor.autocomplete": "Trigger Autocomplete",
  "environment_editor.toggle": "Edit Environments",
  "hotkeys.showHelp": "Show Keyboard Shortcuts",
  "model.create": "New Request",
  "model.duplicate": "Duplicate Request",
  "request.rename": "Rename Active Request",
  "request.send": "Send Active Request",
  "switcher.next": "Go To Previous Request",
  "switcher.prev": "Go To Next Request",
  "switcher.toggle": "Toggle Request Switcher",
  "settings.show": "Open Settings",
  "sidebar.filter": "Filter Sidebar",
  "sidebar.expand_all": "Expand All Folders",
  "sidebar.collapse_all": "Collapse All Folders",
  "sidebar.selected.delete": "Delete Selected Sidebar Item",
  "sidebar.selected.duplicate": "Duplicate Selected Sidebar Item",
  "sidebar.selected.move": "Move Selected to Workspace",
  "sidebar.selected.rename": "Rename Selected Sidebar Item",
  "sidebar.focus": "Focus or Toggle Sidebar",
  "sidebar.context_menu": "Show Context Menu",
  "url_bar.focus": "Focus URL",
  "workspace_settings.show": "Open Workspace Settings",
};

const layoutInsensitiveKeys = [
  "Equal",
  "Minus",
  "BracketLeft",
  "BracketRight",
  "Backquote",
  "Space",
];

export const hotkeyActions: HotkeyAction[] = (
  Object.keys(defaultHotkeys) as (keyof typeof defaultHotkeys)[]
).sort((a, b) => {
  const scopeA = a.split(".")[0] || "";
  const scopeB = b.split(".")[0] || "";
  if (scopeA !== scopeB) {
    return scopeA.localeCompare(scopeB);
  }
  return hotkeyLabels[a].localeCompare(hotkeyLabels[b]);
});

export type HotKeyOptions = {
  enable?: boolean | (() => boolean);
  priority?: number;
  allowDefault?: boolean;
};

interface Callback {
  action: HotkeyAction;
  callback: (e: KeyboardEvent) => void;
  options: HotKeyOptions;
}

const callbacksAtom = atom<Callback[]>([]);
const currentKeysAtom = atom<Set<string>>(new Set([]));
export const sortedCallbacksAtom = atom((get) =>
  [...get(callbacksAtom)].sort((a, b) => (b.options.priority ?? 0) - (a.options.priority ?? 0)),
);

const clearCurrentKeysDebounced = debounce(() => {
  jotaiStore.set(currentKeysAtom, new Set([]));
}, 5000);

export function useHotKey(
  action: HotkeyAction | null,
  callback: (e: KeyboardEvent) => void,
  options: HotKeyOptions = {},
) {
  useEffect(() => {
    if (action == null) return;
    jotaiStore.set(callbacksAtom, (prev) => {
      const without = prev.filter((cb) => {
        const isTheSame = cb.action === action && cb.options.priority === options.priority;
        return !isTheSame;
      });
      const newCb: Callback = { action, callback, options };
      return [...without, newCb];
    });
    return () => {
      jotaiStore.set(callbacksAtom, (prev) => prev.filter((cb) => cb.callback !== callback));
    };
  }, [action, callback, options]);
}

export function useSubscribeHotKeys() {
  useEffect(() => {
    document.addEventListener("keyup", handleKeyUp, { capture: true });
    document.addEventListener("keydown", handleKeyDown, { capture: true });
    return () => {
      document.removeEventListener("keydown", handleKeyDown, { capture: true });
      document.removeEventListener("keyup", handleKeyUp, { capture: true });
    };
  }, []);
}

function handleKeyUp(e: KeyboardEvent) {
  const keyToRemove = layoutInsensitiveKeys.includes(e.code) ? e.code : e.key;
  const currentKeys = new Set(jotaiStore.get(currentKeysAtom));
  currentKeys.delete(keyToRemove);

  // Clear all keys if no longer holding modifier
  // HACK: This is to get around the case of DOWN SHIFT -> DOWN : -> UP SHIFT -> UP ;
  //  As you see, the ":" is not removed because it turned into ";" when shift was released
  const isHoldingModifier = e.altKey || e.ctrlKey || e.metaKey || e.shiftKey;
  if (!isHoldingModifier) {
    currentKeys.clear();
  }

  jotaiStore.set(currentKeysAtom, currentKeys);
}

function handleKeyDown(e: KeyboardEvent) {
  // Don't add key if not holding modifier
  const isValidKeymapKey =
    e.altKey || e.ctrlKey || e.metaKey || e.shiftKey || SINGLE_WHITELIST.includes(e.key);
  if (!isValidKeymapKey) {
    return;
  }

  // Don't add hold keys
  if (HOLD_KEYS.includes(e.key)) {
    return;
  }

  const keyToAdd = layoutInsensitiveKeys.includes(e.code) ? e.code : e.key;
  const currentKeys = new Set(jotaiStore.get(currentKeysAtom));
  currentKeys.add(keyToAdd);

  const currentKeysWithModifiers = new Set(currentKeys);
  if (e.altKey) currentKeysWithModifiers.add("Alt");
  if (e.ctrlKey) currentKeysWithModifiers.add("Control");
  if (e.metaKey) currentKeysWithModifiers.add("Meta");
  if (e.shiftKey) currentKeysWithModifiers.add("Shift");

  // Don't trigger if the user is focused within an element that explicitly disableds hotkeys
  if (document.activeElement?.closest("[data-disable-hotkey]")) {
    return;
  }

  // Don't support certain single-key combinations within inputs
  if (
    (e.target instanceof HTMLInputElement || e.target instanceof HTMLTextAreaElement) &&
    currentKeysWithModifiers.size === 1 &&
    (currentKeysWithModifiers.has("Backspace") || currentKeysWithModifiers.has("Delete"))
  ) {
    return;
  }

  const executed: string[] = [];
  for (const { action, callback, options } of jotaiStore.get(sortedCallbacksAtom)) {
    const enable = typeof options.enable === "function" ? options.enable() : options.enable;
    if (enable === false) {
      continue;
    }

    if (keysMatchAction(Array.from(currentKeysWithModifiers), action)) {
      if (!options.allowDefault) {
        e.preventDefault();
        e.stopPropagation();
      }
      callback(e);
      executed.push(`${action} ${options.priority ?? 0}`);
      break;
    }
  }

  if (executed.length > 0) {
    console.log("Executed hotkey", executed.join(", "));
    jotaiStore.set(currentKeysAtom, new Set([]));
  }
  clearCurrentKeysDebounced();
}

export function useHotkeyLabel(action: HotkeyAction): string {
  return hotkeyLabels[action];
}

export function getHotkeyScope(action: HotkeyAction): string {
  const scope = action.split(".")[0];
  return scope || "";
}

export function formatHotkeyString(trigger: string): string[] {
  const os = type();
  const parts = trigger.split("+");
  const labelParts: string[] = [];

  for (const p of parts) {
    if (os === "macos") {
      if (p === "Meta") {
        labelParts.push("⌘");
      } else if (p === "Shift") {
        labelParts.push("⇧");
      } else if (p === "Control") {
        labelParts.push("⌃");
      } else if (p === "Alt") {
        labelParts.push("⌥");
      } else if (p === "Enter") {
        labelParts.push("↩");
      } else if (p === "Tab") {
        labelParts.push("⇥");
      } else if (p === "Backspace") {
        labelParts.push("⌫");
      } else if (p === "Delete") {
        labelParts.push("⌦");
      } else if (p === "Minus") {
        labelParts.push("-");
      } else if (p === "Plus") {
        labelParts.push("+");
      } else if (p === "Equal") {
        labelParts.push("=");
      } else if (p === "Space") {
        labelParts.push("Space");
      } else {
        labelParts.push(capitalize(p));
      }
    } else {
      if (p === "Control") {
        labelParts.push("Ctrl");
      } else if (p === "Space") {
        labelParts.push("Space");
      } else {
        labelParts.push(capitalize(p));
      }
    }
  }

  if (os === "macos") {
    return labelParts;
  }
  return [labelParts.join("+")];
}

export function useFormattedHotkey(action: HotkeyAction | null): string[] | null {
  const hotkeys = useAtomValue(hotkeysAtom);
  const trigger = action != null ? (hotkeys[action]?.[0] ?? null) : null;
  if (trigger == null) {
    return null;
  }

  return formatHotkeyString(trigger);
}

function compareKeys(keysA: string[], keysB: string[]) {
  if (keysA.length !== keysB.length) return false;
  const sortedA = keysA
    .map((k) => k.toLowerCase())
    .sort()
    .join("::");
  const sortedB = keysB
    .map((k) => k.toLowerCase())
    .sort()
    .join("::");
  return sortedA === sortedB;
}

/** Build the full key combination from a KeyboardEvent including modifiers */
function getKeysFromEvent(e: KeyboardEvent): string[] {
  const keys: string[] = [];
  if (e.altKey) keys.push("Alt");
  if (e.ctrlKey) keys.push("Control");
  if (e.metaKey) keys.push("Meta");
  if (e.shiftKey) keys.push("Shift");

  // Add the actual key (use code for layout-insensitive keys)
  const keyToAdd = layoutInsensitiveKeys.includes(e.code) ? e.code : e.key;
  keys.push(keyToAdd);

  return keys;
}

/** Check if a set of pressed keys matches any hotkey for the given action */
function keysMatchAction(keys: string[], action: HotkeyAction): boolean {
  const hotkeys = getHotkeys();
  const hkKeys = hotkeys[action];
  if (!hkKeys || hkKeys.length === 0) return false;

  for (const hkKey of hkKeys) {
    const hotkeyParts = hkKey.split("+");
    if (compareKeys(hotkeyParts, keys)) {
      return true;
    }
  }
  return false;
}

/** Check if a KeyboardEvent matches a hotkey action */
export function eventMatchesHotkey(e: KeyboardEvent, action: HotkeyAction): boolean {
  const keys = getKeysFromEvent(e);
  return keysMatchAction(keys, action);
}