import {
  Component,
  ElementRef,
  Injector,
  afterNextRender,
  computed,
  effect,
  inject,
  signal,
  viewChild,
} from '@angular/core';
import { NgIcon } from '@ng-icons/core';
import { I18nService } from '@core/i18n.service';
import type { SavedConnection, Stack } from '@shared/types';
import { ConnectionsService } from '@core/connections.service';
import { ConfirmDialog } from '../dialogs/confirm-dialog';
import { PromptDialog } from '../dialogs/prompt-dialog';
import { DialogsService } from '@core/dialogs.service';
import { cycleFocus } from '@core/focus-cycle';
import { FocusService } from '@core/focus.service';
import { blockNativeContextMenu, blockReloadKeys, IS_MAC_CHROME } from '@core/platform';
import { RpcService } from '@core/rpc.service';
import { SettingsService } from '@core/settings.service';
import { ShortcutsService, type ShortcutId } from '@core/shortcuts.service';
import { Toasts } from '../toasts/toasts';

interface Draft {
  id: string;
  name: string;
  stackId: string | null;
  host: string;
  port: number;
  username: string;
  authKind: 'password' | 'key';
  password: string;
  privateKeyPath: string;
  passphrase: string;
  initialPath: string;
  localDir: string;
}

function toDraft(c: SavedConnection): Draft {
  return {
    id: c.id,
    name: c.name,
    stackId: c.stackId,
    host: c.host,
    port: c.port,
    username: c.username,
    // agent auth only exists on ~/.ssh/config hosts, which never reach this form
    authKind: c.auth.kind === 'password' ? 'password' : 'key',
    password: c.auth.kind === 'password' ? c.auth.password : '',
    privateKeyPath: c.auth.kind === 'key' ? c.auth.privateKeyPath : '',
    passphrase: c.auth.kind === 'key' ? (c.auth.passphrase ?? '') : '',
    initialPath: c.initialPath ?? '',
    localDir: c.localDir ?? '',
  };
}

function fromDraft(d: Draft): SavedConnection {
  return {
    id: d.id,
    name: d.name.trim() || `${d.username}@${d.host}`,
    stackId: d.stackId,
    host: d.host.trim(),
    port: d.port || 22,
    username: d.username.trim(),
    auth:
      d.authKind === 'password'
        ? { kind: 'password', password: d.password }
        : {
            kind: 'key',
            privateKeyPath: d.privateKeyPath.trim(),
            ...(d.passphrase ? { passphrase: d.passphrase } : {}),
          },
    initialPath: d.initialPath.trim() || null,
    localDir: d.localDir.trim() || null,
  };
}

/**
 * Root component of the connection-manager window (__APP_MODE === 'manager').
 * Modal to the main window (enforced bun-side); connect/open-stack requests
 * are executed by the MAIN window — this window never touches panels.
 */
@Component({
  selector: 'app-root',
  imports: [NgIcon, ConfirmDialog, PromptDialog, Toasts],
  templateUrl: './connection-manager.html',
  host: {
    '(window:keydown)': 'onWindowKeydown($event)',
    '(window:focusin)': 'rememberFocus($event)',
    '(window:contextmenu)': 'blockContextMenu($event)',
  },
})
export class ConnectionManager {
  readonly i18n = inject(I18nService);
  readonly store = inject(ConnectionsService);
  readonly dialogs = inject(DialogsService);
  readonly isMacChrome = IS_MAC_CHROME;
  private readonly rpc = inject(RpcService);
  // injected for its side effects: fetches settings and applies theme/accent/
  // text-size data attributes to this window's document root
  private readonly settings = inject(SettingsService);
  readonly shortcuts = inject(ShortcutsService);
  private readonly focus = inject(FocusService);
  private readonly injector = inject(Injector);
  private readonly list = viewChild.required<ElementRef<HTMLElement>>('list');
  private readonly nameBox = viewChild<ElementRef<HTMLInputElement>>('nameBox');
  /** Where focus was outside a dialog, to come back to when it closes. */
  private lastFocus: HTMLElement | null = null;

  readonly draft = signal<Draft | null>(null);
  readonly busy = signal(false);
  readonly importing = signal(false);
  /** The More… section (local directory) in the edit form. */
  readonly moreOpen = signal(false);
  /** Connection id being dragged between stacks. */
  readonly draggedId = signal<string | null>(null);
  /** Highlighted drop target: a stack id, 'loose', or null. */
  readonly dropTarget = signal<string | null>(null);

  constructor() {
    // the keyboard starts in the list — and lands there again whenever focus
    // fell to <body> (the store loads after the first render; a deleted row
    // takes its focus with it)
    effect(() => {
      this.store.grouped();
      afterNextRender(() => this.focusFallback(), { injector: this.injector });
    });
    // dialogs bump FocusService when they close: return to where the user was
    effect(() => {
      this.focus.tick();
      afterNextRender(
        () => {
          if (this.lastFocus?.isConnected) this.lastFocus.focus();
          else this.focusFallback();
        },
        { injector: this.injector },
      );
    });
  }

  readonly valid = computed(() => {
    const d = this.draft();
    if (!d) return false;
    if (!d.host.trim() || !d.username.trim()) return false;
    if (d.authKind === 'key' && !d.privateKeyPath.trim()) return false;
    return true;
  });

  patch<K extends keyof Draft>(key: K, value: Draft[K]): void {
    this.draft.update((d) => (d ? { ...d, [key]: value } : d));
  }

  newConnection(): void {
    this.moreOpen.set(false);
    this.draft.set({
      id: '',
      name: '',
      stackId: null,
      host: '',
      port: 22,
      username: 'root',
      authKind: 'password',
      password: '',
      privateKeyPath: '',
      passphrase: '',
      initialPath: '',
      localDir: '',
    });
  }

  edit(connection: SavedConnection): void {
    this.draft.set(toDraft(connection));
    this.moreOpen.set(!!connection.localDir);
  }

  close(): void {
    void this.rpc.request.managerClose({});
  }

  /**
   * This window's keys (the `manager` scope), then the fixed ones: Esc closes
   * the window — from a text field it first just leaves the field, so a
   * half-typed connection isn't thrown away — and Tab is walked by hand
   * (WKWebView skips buttons and radios on Tab otherwise). The dialogs take
   * their own Esc and stop it, so it never reaches here.
   */
  onWindowKeydown(event: KeyboardEvent): void {
    const id = this.shortcuts.claim(event, 'manager');
    if (id) this.runCommand(id);
    else if (event.key === 'Escape' && !this.dialogs.anyOpen) this.onEscape(event);
    else cycleFocus(document.body, event);
    blockReloadKeys(event);
  }

  private onEscape(event: KeyboardEvent): void {
    event.preventDefault();
    if (this.shortcuts.isTypingTarget(event)) {
      (event.target as HTMLElement).blur();
      this.focusFallback(true);
    } else {
      this.close();
    }
  }

  private runCommand(id: ShortcutId): void {
    const row = this.focusedRow();
    switch (id) {
      case 'close-window':
        this.close();
        break;
      case 'conn-new':
        this.newConnection();
        this.focusName();
        break;
      case 'conn-new-stack':
        this.newStack();
        break;
      case 'conn-save':
        void this.save();
        break;
      case 'conn-connect':
        // the focused stack opens in tabs; a focused connection, or the form, connects
        if (row?.stack) this.openStack(row.stack.id);
        else {
          if (row?.connection) this.edit(row.connection);
          void this.saveAndConnect();
        }
        break;
      case 'conn-delete':
        if (row?.stack) this.deleteStack(row.stack);
        else {
          if (row?.connection) this.edit(row.connection);
          this.deleteCurrent();
        }
        break;
      case 'conn-rename-stack':
        if (row?.stack) this.renameStack(row.stack);
        break;
      case 'conn-import':
        void this.importWinScp();
        break;
      case 'scale-up':
        this.settings.setUiScale(this.settings.uiScale() + 0.1);
        break;
      case 'scale-down':
        this.settings.setUiScale(this.settings.uiScale() - 0.1);
        break;
      case 'scale-reset':
        this.settings.setUiScale(1);
        break;
    }
  }

  // ---- keyboard: the list ----

  /** The stack or connection row the focus sits in (its buttons included). */
  private focusedRow(): { stack?: Stack; connection?: SavedConnection } | null {
    const el = document.activeElement as HTMLElement | null;
    const stackId = el?.closest<HTMLElement>('[data-stack]')?.dataset['stack'];
    if (stackId) {
      const stack = this.store.stacks().find((s) => s.id === stackId);
      return stack ? { stack } : null;
    }
    const connId = el?.closest<HTMLElement>('[data-conn]')?.dataset['conn'];
    const connection = connId && this.store.connections().find((c) => c.id === connId);
    return connection ? { connection } : null;
  }

  private rows(): HTMLElement[] {
    return [...this.list().nativeElement.querySelectorAll<HTMLElement>('[data-row]')];
  }

  /**
   * ↑ ↓ Home End move between rows (focus only — loading a connection would
   * replace the form without asking); ← / → collapse and expand a stack, ← on
   * a connection goes up to its stack; Enter on a connection opens it in the
   * form (Enter / Space on a stack toggles it, natively).
   */
  onListKeydown(event: KeyboardEvent): void {
    if (event.metaKey || event.ctrlKey || event.altKey) return;
    const rows = this.rows();
    const at = rows.indexOf(document.activeElement as HTMLElement);
    const row = this.focusedRow();
    let target: HTMLElement | undefined;
    switch (event.key) {
      case 'ArrowDown':
        target = rows[Math.min(rows.length - 1, at + 1)];
        break;
      case 'ArrowUp':
        target = rows[Math.max(0, at - 1)];
        break;
      case 'Home':
        target = rows[0];
        break;
      case 'End':
        target = rows.at(-1);
        break;
      case 'ArrowLeft':
        if (row?.stack && !row.stack.collapsed) this.toggleStack(row.stack);
        else if (row?.connection?.stackId) target = this.stackRow(row.connection.stackId);
        else return;
        break;
      case 'ArrowRight':
        if (row?.stack?.collapsed) this.toggleStack(row.stack);
        else return;
        break;
      case 'Enter':
        if (!row?.connection) return;
        this.edit(row.connection);
        this.focusName();
        break;
      default:
        return;
    }
    event.preventDefault();
    target?.focus();
  }

  private stackRow(stackId: string): HTMLElement | undefined {
    return this.rows().find((el) => el.closest<HTMLElement>('[data-stack]')?.dataset['stack'] === stackId);
  }

  /** Enter in a form field = Connect, the primary button (not mid-IME). */
  onFormEnter(event: Event): void {
    const key = event as KeyboardEvent;
    const target = key.target as HTMLElement;
    if (key.isComposing || !target.matches('input:not([type=radio]):not([type=checkbox])')) return;
    key.preventDefault();
    if (this.valid()) void this.saveAndConnect();
  }

  rememberFocus(event: FocusEvent): void {
    const target = event.target as HTMLElement;
    if (target instanceof HTMLElement && !target.closest('[role=dialog]')) this.lastFocus = target;
  }

  /** Focus the edited connection's row, else the first row — only when focus
   *  is nowhere (on <body>), unless forced. */
  private focusFallback(force = false): void {
    if (!force && document.activeElement !== document.body) return;
    const id = this.draft()?.id;
    const own = id ? this.rows().find((el) => el.closest<HTMLElement>('[data-conn]')?.dataset['conn'] === id) : undefined;
    (own ?? this.rows()[0])?.focus();
  }

  private focusName(): void {
    afterNextRender(() => this.nameBox()?.nativeElement.focus(), { injector: this.injector });
  }

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

  async save(): Promise<string | null> {
    const d = this.draft();
    if (!d || !this.valid()) return null;
    const id = await this.store.upsert(fromDraft(d));
    if (id) this.patch('id', id);
    return id;
  }

  async saveAndConnect(): Promise<void> {
    if (!this.draft()) return;
    this.busy.set(true);
    try {
      const id = await this.save();
      if (!id) return;
      // the main window connects (and this window closes); a failed connect
      // surfaces as an error there
      await this.rpc.request.managerConnect({ id });
    } finally {
      this.busy.set(false);
    }
  }

  deleteCurrent(): void {
    const d = this.draft();
    if (!d?.id) {
      this.draft.set(null);
      return;
    }
    this.dialogs.confirm.set({
      title: this.i18n.t('connMgr.deleteConnectionTitle'),
      body: this.i18n.t('connMgr.deleteConnectionBody', { name: d.name || d.host }),
      confirmLabel: this.i18n.t('common.delete'),
      destructive: true,
      onConfirm: async () => {
        await this.store.remove(d.id);
        this.draft.set(null);
      },
    });
  }

  async pickKeyFile(): Promise<void> {
    const res = await this.rpc.request.pickKeyFile({});
    if (res.ok && res.path) this.patch('privateKeyPath', res.path);
  }

  async importWinScp(): Promise<void> {
    this.importing.set(true);
    try {
      await this.store.importWinScp();
    } finally {
      this.importing.set(false);
    }
  }

  // ---- stacks ----

  openStack(stackId: string): void {
    // opened as tabs in the main window; bun closes this window after
    void this.rpc.request.managerOpenStack({ id: stackId });
  }

  toggleStack(stack: Stack): void {
    void this.store.upsertStack({ ...stack, collapsed: !stack.collapsed });
  }

  newStack(): void {
    this.dialogs.prompt.set({
      title: this.i18n.t('connMgr.newStackTitle'),
      placeholder: this.i18n.t('connMgr.newStackPrompt'),
      confirmLabel: this.i18n.t('fileActions.createConfirm'),
      onConfirm: (name) => void this.store.upsertStack({ id: '', name }),
    });
  }

  renameStack(stack: Stack): void {
    this.dialogs.prompt.set({
      title: this.i18n.t('connMgr.renameStackTitle'),
      initial: stack.name,
      confirmLabel: this.i18n.t('connMgr.renameStack'),
      onConfirm: (name) => void this.store.upsertStack({ ...stack, name }),
    });
  }

  deleteStack(stack: Stack): void {
    this.dialogs.confirm.set({
      title: this.i18n.t('connMgr.deleteStackTitle'),
      body: this.i18n.t('connMgr.deleteStackBody', { name: stack.name }),
      confirmLabel: this.i18n.t('common.delete'),
      destructive: true,
      onConfirm: () => void this.store.removeStack(stack.id),
    });
  }

  // ---- drag & drop (move a connection between stacks / loose) ----

  onDragStart(event: DragEvent, connection: SavedConnection): void {
    this.draggedId.set(connection.id);
    event.dataTransfer?.setData('text/plain', connection.id);
    if (event.dataTransfer) event.dataTransfer.effectAllowed = 'move';
  }

  onDragOver(event: DragEvent, target: string): void {
    if (!this.draggedId()) return;
    event.preventDefault();
    this.dropTarget.set(target);
  }

  onDrop(event: DragEvent, stackId: string | null): void {
    event.preventDefault();
    const id = this.draggedId();
    this.draggedId.set(null);
    this.dropTarget.set(null);
    const connection = this.store.connections().find((c) => c.id === id);
    if (!connection || connection.stackId === stackId) return;
    void this.store.upsert({ ...connection, stackId });
  }

  onDragEnd(): void {
    this.draggedId.set(null);
    this.dropTarget.set(null);
  }
}