import { keymap } from 'prosemirror-keymap';
import { baseKeymap, chainCommands, exitCode } from 'prosemirror-commands';
import { undo, redo } from 'prosemirror-history';
import { undoInputRule } from 'prosemirror-inputrules';
import {
  splitListItem,
  liftListItem,
  sinkListItem,
} from 'prosemirror-schema-list';
import { Command, Plugin } from 'prosemirror-state';
import { Schema } from 'prosemirror-model';
import { getCommand } from './commands';
import { plainTextSlice } from './plugins/paste';

const isMac =
  typeof navigator !== 'undefined' && /Mac|iP(hone|[oa]d)/.test(navigator.platform);

export interface KeymapOptions {
  /** Invoked on Mod-k so the host can open its link editor UI. */
  onLinkShortcut?: () => void;
  /** Invoked on Mod-f so the host can open its find & replace bar. */
  onFindShortcut?: () => void;
  /** Invoked on Mod-/ so the host can open its shortcut help dialog. */
  onShortcutHelp?: () => void;
}

/**
 * Editor keymap. Returned as two plugins: feature bindings first, then the
 * ProseMirror base keymap as fallback.
 */
export function buildKeymapPlugins(schema: Schema, options: KeymapOptions = {}): Plugin[] {
  const keys: Record<string, Command> = {};

  keys['Mod-z'] = undo;
  keys['Shift-Mod-z'] = redo;
  if (!isMac) keys['Mod-y'] = redo;
  keys['Backspace'] = undoInputRule;

  keys['Mod-b'] = (state, dispatch, view) =>
    getCommand(state, 'bold')!(state, dispatch, view);
  keys['Mod-i'] = (state, dispatch, view) =>
    getCommand(state, 'italic')!(state, dispatch, view);
  keys['Mod-u'] = (state, dispatch, view) =>
    getCommand(state, 'underline')!(state, dispatch, view);
  keys['Shift-Mod-x'] = (state, dispatch, view) =>
    getCommand(state, 'strike')!(state, dispatch, view);
  // Google Docs convention: Ctrl+, subscript, Ctrl+. superscript.
  keys['Mod-,'] = (state, dispatch, view) =>
    getCommand(state, 'subscript')!(state, dispatch, view);
  keys['Mod-.'] = (state, dispatch, view) =>
    getCommand(state, 'superscript')!(state, dispatch, view);

  // Paste without formatting. Reads the clipboard directly so the result is
  // plain text regardless of the persistent toggle; falls back to the
  // browser default when the async Clipboard API is unavailable.
  keys['Shift-Mod-v'] = (_state, _dispatch, view) => {
    if (!view || typeof navigator === 'undefined' || !navigator.clipboard?.readText) {
      return false;
    }
    navigator.clipboard
      .readText()
      .then(text => {
        if (!text || !view) return;
        const slice = plainTextSlice(view.state.schema, text);
        view.dispatch(view.state.tr.replaceSelection(slice).scrollIntoView());
      })
      .catch(() => {
        /* clipboard denied — silently no-op */
      });
    return true;
  };

  keys['Shift-Ctrl-0'] = (state, dispatch, view) =>
    getCommand(state, 'paragraph')!(state, dispatch, view);
  for (let level = 1; level <= 6; level += 1) {
    keys[`Shift-Ctrl-${level}`] = (state, dispatch, view) =>
      getCommand(state, 'heading', { level })!(state, dispatch, view);
  }

  keys['Shift-Mod-7'] = (state, dispatch, view) =>
    getCommand(state, 'orderedList')!(state, dispatch, view);
  keys['Shift-Mod-8'] = (state, dispatch, view) =>
    getCommand(state, 'bulletList')!(state, dispatch, view);
  keys['Shift-Mod-9'] = (state, dispatch, view) =>
    getCommand(state, 'blockquote')!(state, dispatch, view);
  keys['Mod-Alt-c'] = (state, dispatch, view) =>
    getCommand(state, 'codeBlock')!(state, dispatch, view);

  // Google Docs convention: Mod-] / Mod-[ indent and outdent.
  keys['Mod-]'] = (state, dispatch, view) =>
    getCommand(state, 'indent')!(state, dispatch, view);
  keys['Mod-['] = (state, dispatch, view) =>
    getCommand(state, 'outdent')!(state, dispatch, view);

  // New task items always start unchecked.
  keys['Enter'] = chainCommands(
    splitListItem(schema.nodes.task_item, { checked: false }),
    splitListItem(schema.nodes.list_item)
  );
  keys['Tab'] = chainCommands(
    sinkListItem(schema.nodes.task_item),
    sinkListItem(schema.nodes.list_item)
  );
  keys['Shift-Tab'] = chainCommands(
    liftListItem(schema.nodes.task_item),
    liftListItem(schema.nodes.list_item)
  );

  // Hard break; exitCode first so breaks escape code marks cleanly.
  const br: Command = chainCommands(exitCode, (state, dispatch) => {
    if (dispatch) {
      dispatch(
        state.tr.replaceSelectionWith(schema.nodes.hard_break.create()).scrollIntoView()
      );
    }
    return true;
  });
  keys['Shift-Enter'] = br;
  keys['Mod-Enter'] = br;

  if (options.onLinkShortcut) {
    const open = options.onLinkShortcut;
    keys['Mod-k'] = () => {
      open();
      return true;
    };
  }

  if (options.onFindShortcut) {
    const openFind = options.onFindShortcut;
    keys['Mod-f'] = () => {
      openFind();
      return true;
    };
  }

  if (options.onShortcutHelp) {
    const openHelp = options.onShortcutHelp;
    keys['Mod-/'] = () => {
      openHelp();
      return true;
    };
  }

  return [keymap(keys), keymap(baseKeymap)];
}