import { Component, ElementRef, afterNextRender, computed, inject, signal, viewChild } from '@angular/core';
import { NgIcon } from '@ng-icons/core';
import { BRANDING } from '@shared/branding';
import { LOCALE_LABELS, SUPPORTED } from '@shared/i18n';
import {
  type Combo,
  comboFromEvent,
  conflicts,
  firesInTextField,
  GROUPS,
  isReserved,
  ownerOf,
  type ResolvedBinding,
  sameCombo,
  type ShortcutId,
  typesCharacter,
} from '@shared/keymap';
import { COLUMN_KEYS } from '@core/context-menu.service';
import { cycleFocus } from '@core/focus-cycle';
import { I18nService } from '@core/i18n.service';
import { blockNativeContextMenu, blockReloadKeys, IS_MAC, IS_MAC_CHROME } from '@core/platform';
import { RpcService } from '@core/rpc.service';
import { SettingsService } from '@core/settings.service';
import { ShortcutsService } from '@core/shortcuts.service';

const SECTIONS = ['appearance', 'transfers', 'editor', 'fileList', 'keyboard', 'about'] as const;
type Section = (typeof SECTIONS)[number];

const THEMES = ['system', 'light', 'dark'] as const;
const DARK_TONES = ['dark', 'darker'] as const;
const SPEED_UNITS = [
  { value: 'MBps', label: 'MB/s' },
  { value: 'Mbps', label: 'Mbps' },
] as const;
const TRANSFER_MODES = ['single', 'multi'] as const;
const CONCURRENCY_CHOICES = [2, 3, 4, 6, 8] as const;

/** The keys no remap moves, listed read-only under the editable ones. */
const FIXED_LINES = ['escape', 'escList', 'dialogs', 'menus', 'filter', 'shift', 'find', 'manager', 'sidebar'] as const;

/** A recording that could not simply be added: explained under its row. */
interface CaptureNote {
  id: ShortcutId;
  kind: 'reserved' | 'needsModifier' | 'conflict';
  combo: Combo;
  /** conflict: the command that already owns the combo. */
  owner?: ShortcutId;
}

/**
 * Root of the Settings window (APP_MODE 'settings'). Every control is a plain
 * SettingsService setter: the save goes to bun, which rebroadcasts it, so the
 * other windows follow live while this one stays open — keyboard remaps
 * included (menu hints, tooltips and the macOS menu bar follow at once).
 */
@Component({
  selector: 'app-root',
  imports: [NgIcon],
  templateUrl: './settings-window.html',
  host: {
    '(window:keydown)': 'onWindowKeydown($event)',
    '(window:contextmenu)': 'blockContextMenu($event)',
    '(window:mousedown)': 'onWindowMousedown($event)',
    '(window:blur)': 'capturing.set(null)',
  },
})
export class SettingsWindow {
  readonly settings = inject(SettingsService);
  readonly i18n = inject(I18nService);
  readonly shortcuts = inject(ShortcutsService);
  private readonly rpc = inject(RpcService);

  readonly isMacChrome = IS_MAC_CHROME;
  readonly sections = SECTIONS;
  readonly section = signal<Section>('appearance');
  readonly localeOptions = SUPPORTED;
  readonly localeLabels = LOCALE_LABELS;
  readonly themes = THEMES;
  readonly darkTones = DARK_TONES;
  readonly speedUnits = SPEED_UNITS;
  readonly transferModes = TRANSFER_MODES;
  readonly concurrencyChoices = CONCURRENCY_CHOICES;
  readonly columnKeys = COLUMN_KEYS;
  readonly fixedLines = FIXED_LINES;
  readonly appName = BRANDING.appName;
  readonly buildLabel = BRANDING.buildLabel;
  /** "100%" for the stepper readout; the value itself lives in settings. */
  readonly scalePercent = computed(() => `${Math.round(this.settings.uiScale() * 100)}%`);

  private readonly nav = viewChild.required<ElementRef<HTMLElement>>('nav');

  // ---- Settings → Keyboard ----
  readonly keyFilter = signal('');
  /** The command being recorded, if any. */
  readonly capturing = signal<ShortcutId | null>(null);
  readonly note = signal<CaptureNote | null>(null);
  readonly confirmResetAll = signal(false);
  readonly anyCustom = computed(() => this.shortcuts.keymap().some((b) => b.custom));
  private readonly conflictMap = computed(() => conflicts(this.shortcuts.keymap()));

  /** The editable rows by group, narrowed by the search field (label or keys). */
  readonly keyGroups = computed(() => {
    const query = this.keyFilter().trim().toLowerCase();
    const keymap = this.shortcuts.keymap();
    return GROUPS.map((group) => ({
      id: group,
      rows: keymap.filter((b) => b.group === group && (!query || this.rowText(b).includes(query))),
    })).filter((group) => group.rows.length);
  });

  /** The fixed keys, in this platform's spelling, for the read-only lines. */
  readonly fixedKeys = computed(() => ({
    esc: this.shortcuts.fixedKey('Escape'),
    enter: this.shortcuts.fixedKey('Enter'),
    shiftEnter: this.shortcuts.fixedKey('Shift+Enter'),
    tab: this.shortcuts.fixedKey('Tab'),
    shiftTab: this.shortcuts.fixedKey('Shift+Tab'),
    backspace: this.shortcuts.fixedKey('Backspace'),
    home: this.shortcuts.fixedKey('Home'),
    end: this.shortcuts.fixedKey('End'),
  }));

  constructor() {
    // the keyboard starts on the current section
    afterNextRender(() => this.sectionButton(this.section())?.focus());
  }

  /** "Visual Studio Code.app" -> "Visual Studio Code"; empty -> system default. */
  editorAppName(): string {
    const path = this.settings.editorApp();
    if (!path) return this.i18n.t('options.systemDefault');
    const base = path.split('/').filter(Boolean).pop() ?? path;
    return base.replace(/\.app$/i, '');
  }

  async pickEditorApp(): Promise<void> {
    const res = await this.rpc.request.pickEditorApp({});
    if (res.ok && res.path) this.settings.setEditorApp(res.path);
  }

  showAbout(): void {
    void this.rpc.request.showAbout({});
  }

  // ---- sections ----

  /** ↑ / ↓ in the sidebar move between sections (and focus follows). */
  onNavKeydown(event: KeyboardEvent): void {
    const step = event.key === 'ArrowDown' ? 1 : event.key === 'ArrowUp' ? -1 : 0;
    if (!step) return;
    event.preventDefault();
    const next = SECTIONS[(SECTIONS.indexOf(this.section()) + step + SECTIONS.length) % SECTIONS.length];
    this.section.set(next);
    this.sectionButton(next)?.focus();
  }

  private sectionButton(section: Section): HTMLElement | null {
    return this.nav().nativeElement.querySelector<HTMLElement>(`[data-section="${section}"]`);
  }

  // ---- keyboard remaps ----

  rowLabel(binding: ResolvedBinding): string {
    return binding.n
      ? this.i18n.t('keys.go-to-tab', { n: binding.n })
      : this.i18n.t(`keys.${binding.id}`);
  }

  private labelOf(id: ShortcutId): string {
    const binding = this.shortcuts.binding(id);
    return binding ? this.rowLabel(binding) : id;
  }

  private rowText(binding: ResolvedBinding): string {
    return [this.rowLabel(binding), ...binding.combos.map((c) => this.shortcuts.format(c))]
      .join(' ')
      .toLowerCase();
  }

  /** "Rename, Edit" when this row shares a key with others that can collide. */
  conflictWith(binding: ResolvedBinding): string {
    return (this.conflictMap().get(binding.id) ?? []).map((id) => this.labelOf(id)).join(', ');
  }

  /** A plain character key on a file-list row: typing it no longer filters. */
  filterKey(binding: ResolvedBinding): string {
    if (!binding.scopes.some((s) => s === 'panel' || s === 'main')) return '';
    const plain = binding.combos.find(typesCharacter);
    return plain ? this.shortcuts.format(plain) : '';
  }

  noteText(note: CaptureNote): string {
    const key = this.shortcuts.format(note.combo);
    if (note.kind === 'reserved') return this.i18n.t('keys.ui.reserved', { key });
    if (note.kind === 'needsModifier') return this.i18n.t('keys.ui.needsModifier', { key });
    return this.i18n.t('keys.ui.usedBy', { key, action: note.owner ? this.labelOf(note.owner) : '' });
  }

  startCapture(id: ShortcutId): void {
    this.note.set(null);
    this.capturing.set(this.capturing() === id ? null : id);
  }

  /**
   * One keydown while recording, taken before every other key in this window
   * (⌘W records instead of closing). A bare modifier keeps waiting; Esc on its
   * own cancels. Reserved combos are refused WITHOUT preventDefault, so ⌘Q
   * still quits and ⌘C still copies.
   */
  private record(event: KeyboardEvent, id: ShortcutId): void {
    const combo = comboFromEvent(event, IS_MAC);
    if (combo && isReserved(combo, IS_MAC)) {
      this.capturing.set(null);
      this.note.set({ id, kind: 'reserved', combo });
      return;
    }
    event.preventDefault();
    event.stopPropagation();
    if (event.repeat || !combo) return;
    const bare = !combo.mod && !combo.ctrl && !combo.alt && !combo.shift;
    this.capturing.set(null);
    if (bare && combo.key === 'Escape') return;
    const binding = this.shortcuts.binding(id);
    if (!binding || binding.combos.some((c) => sameCombo(c, combo))) return;
    // the editor's text area always has focus: a plain key could never fire there
    if (binding.scopes.includes('editor') && !firesInTextField(combo, IS_MAC)) {
      this.note.set({ id, kind: 'needsModifier', combo });
      return;
    }
    const owner = ownerOf(this.shortcuts.keymap(), combo, binding.scopes, id);
    if (owner) {
      this.note.set({ id, kind: 'conflict', combo, owner: owner.id });
      return;
    }
    this.shortcuts.rebind({ [id]: [...binding.combos, combo] });
  }

  /** "Replace": the key moves from the command that had it to this one. */
  replaceConflict(): void {
    const note = this.note();
    const binding = note && this.shortcuts.binding(note.id);
    const owner = note?.owner && this.shortcuts.binding(note.owner);
    if (!note || !binding || !owner) return;
    this.shortcuts.rebind({
      [note.id]: [...binding.combos, note.combo],
      [owner.id]: owner.combos.filter((c) => !sameCombo(c, note.combo)),
    });
    this.note.set(null);
  }

  removeCombo(binding: ResolvedBinding, index: number): void {
    this.shortcuts.rebind({ [binding.id]: binding.combos.filter((_, i) => i !== index) });
  }

  resetRow(binding: ResolvedBinding): void {
    this.shortcuts.rebind({ [binding.id]: binding.defaults });
    if (this.note()?.id === binding.id) this.note.set(null);
  }

  resetAll(): void {
    this.shortcuts.resetAll();
    this.confirmResetAll.set(false);
    this.note.set(null);
  }

  // ---- window ----

  /** Recording first; then this window's keys (close-window, the scale) and
   *  Tab, walked by hand — WKWebView skips buttons on Tab otherwise. */
  onWindowKeydown(event: KeyboardEvent): void {
    const recording = this.capturing();
    if (recording) {
      this.record(event, recording);
      return;
    }
    const id = this.shortcuts.claim(event, 'settings');
    if (id === 'close-window') void this.rpc.request.settingsClose({});
    else if (id === 'scale-up') this.settings.setUiScale(this.settings.uiScale() + 0.1);
    else if (id === 'scale-down') this.settings.setUiScale(this.settings.uiScale() - 0.1);
    else if (id === 'scale-reset') this.settings.setUiScale(1);
    else if (!id) cycleFocus(document.body, event);
    blockReloadKeys(event);
  }

  /** A click anywhere but a record button ends a recording. */
  onWindowMousedown(event: MouseEvent): void {
    if (this.capturing() && !(event.target as Element).closest('[data-record]')) {
      this.capturing.set(null);
    }
  }

  blockContextMenu(event: Event): void {
    blockNativeContextMenu(event);
  }
}