import {
  Component,
  ElementRef,
  computed,
  effect,
  inject,
  input,
  signal,
  viewChild,
} from '@angular/core';
import { NgIcon } from '@ng-icons/core';
import type { FileEntry, SavedConnection } from '@shared/types';
import { ConnectionsService } from '../connections.service';
import { DialogsService } from '../dialogs.service';
import { FileActionsService } from '../file-actions.service';
import { fileGlyph, fileIconClass } from '../file-icons';
import { formatDate, formatSize } from '../format';
import { PanelsService, type Side, type SortKey } from '../panels.service';
import { SettingsService } from '../settings.service';
import { TransfersService } from '../transfers.service';

@Component({
  selector: 'app-file-panel',
  imports: [NgIcon],
  templateUrl: './file-panel.html',
  host: { class: '@container flex min-w-0 flex-1 flex-col overflow-hidden' },
})
export class FilePanel {
  readonly side = input.required<Side>();

  readonly panels = inject(PanelsService);
  readonly actions = inject(FileActionsService);
  readonly transfers = inject(TransfersService);
  readonly connections = inject(ConnectionsService);
  readonly dialogs = inject(DialogsService);
  private readonly settings = inject(SettingsService);
  readonly panel = computed(() => this.panels.get(this.side()));
  readonly isActive = computed(() => this.panels.activeSide() === this.side());
  readonly isRemote = computed(() => this.panel().sessionId() !== 'local');
  /** The copy button points toward the other panel. */
  readonly copyIcon = computed(() => (this.side() === 'left' ? 'mynaArrowRight' : 'mynaArrowLeft'));

  readonly pathDraft = signal('');
  readonly menuOpen = signal(false);

  private readonly listEl = viewChild.required<ElementRef<HTMLDivElement>>('list');
  private lastClickedIndex = 0;

  readonly formatSize = formatSize;
  readonly formatDate = formatDate;

  constructor() {
    // keep the editable path bar in sync with the actual cwd
    effect(() => this.pathDraft.set(this.panel().cwd()));
    // focus follows the active side (Tab switches panels, dialogs refocus on close)
    effect(() => {
      this.panels.focusTick();
      if (this.isActive()) this.listEl().nativeElement.focus();
    });
  }

  activate(): void {
    this.panels.setActiveSide(this.side());
  }

  copyToOther(): void {
    this.activate();
    void this.transfers.copyToOtherPanel(this.side());
  }

  run(action: 'edit' | 'rename' | 'mkdir' | 'createFile' | 'chmod' | 'delete'): void {
    this.activate();
    void this.actions[action](this.panel());
  }

  pickLocal(): void {
    this.menuOpen.set(false);
    void this.panels.disconnectPanel(this.side());
  }

  pickConnection(connection: SavedConnection): void {
    this.menuOpen.set(false);
    this.activate();
    void this.panels.connectPanel(this.side(), connection, connection.name);
  }

  openManager(): void {
    this.menuOpen.set(false);
    this.activate();
    this.dialogs.manager.set(true);
  }

  disconnect(): void {
    void this.panels.disconnectPanel(this.side());
  }

  iconFor(entry: FileEntry): string {
    return fileGlyph(entry, this.settings.iconColors() === 'multi');
  }

  iconClass(entry: FileEntry): string {
    return fileIconClass(entry, this.settings.iconColors() === 'multi');
  }

  isSelected(entry: FileEntry): boolean {
    return this.panel().selected().has(entry.name);
  }

  clearFilter(): void {
    this.panel().setFilter('');
    this.listEl().nativeElement.focus();
  }

  filterMatches(): number {
    return this.panel()
      .sorted()
      .filter((e) => e.name !== '..').length;
  }

  sortIndicator(key: SortKey): string {
    if (this.panel().sortKey() !== key) return '';
    return this.panel().sortAsc() ? '↑' : '↓';
  }

  commitPath(): void {
    const value = this.pathDraft().trim();
    if (value) void this.panel().load(value);
    this.listEl().nativeElement.focus();
  }

  resetPath(): void {
    this.pathDraft.set(this.panel().cwd());
    this.listEl().nativeElement.focus();
  }

  rowClick(event: MouseEvent, index: number): void {
    this.activate();
    const panel = this.panel();
    if (event.shiftKey) {
      panel.selectRange(this.lastClickedIndex, index);
    } else if (event.metaKey || event.ctrlKey) {
      const entry = panel.sorted()[index];
      if (entry) panel.toggleSelect(entry.name);
    } else {
      panel.clearSelection();
    }
    panel.cursor.set(index);
    this.lastClickedIndex = index;
  }

  rowContextMenu(event: MouseEvent, index: number): void {
    event.preventDefault();
    event.stopPropagation();
    this.activate();
    const panel = this.panel();
    const entry = panel.sorted()[index] ?? null;
    // standard behavior: keep the selection when right-clicking inside it
    if (entry && !panel.selected().has(entry.name)) panel.clearSelection();
    panel.cursor.set(index);
    void this.actions.openContextMenu({ side: this.side(), panel, entry });
  }

  listContextMenu(event: MouseEvent): void {
    event.preventDefault();
    this.activate();
    void this.actions.openContextMenu({ side: this.side(), panel: this.panel(), entry: null });
  }

  openAt(index: number): void {
    const entry = this.panel().sorted()[index];
    if (entry) this.panel().open(entry);
  }

  onKeydown(event: KeyboardEvent): void {
    const panel = this.panel();
    const key = event.key;

    if (key === 'Tab') {
      event.preventDefault();
      this.panels.setActiveSide(this.panels.otherSide(this.side()));
      return;
    }
    if ((event.metaKey || event.ctrlKey) && key.toLowerCase() === 'a') {
      event.preventDefault();
      panel.selectAll();
      return;
    }

    // type-to-filter: printable characters build the query (Space only once a
    // query exists — an empty-filter Space keeps its toggle-select meaning)
    if (
      key.length === 1 &&
      !event.metaKey &&
      !event.ctrlKey &&
      !event.altKey &&
      (key !== ' ' || panel.filter() !== '')
    ) {
      event.preventDefault();
      panel.setFilter(panel.filter() + key);
      this.scrollCursorIntoView();
      return;
    }
    if (key === 'Backspace' && panel.filter() !== '') {
      event.preventDefault();
      panel.setFilter(panel.filter().slice(0, -1));
      return;
    }
    if (key === 'Escape' && panel.filter() !== '') {
      event.preventDefault();
      panel.setFilter('');
      return;
    }

    switch (key) {
      case 'ArrowDown':
        panel.moveCursor(1);
        break;
      case 'ArrowUp':
        panel.moveCursor(-1);
        break;
      case 'PageDown':
        panel.moveCursor(20);
        break;
      case 'PageUp':
        panel.moveCursor(-20);
        break;
      case 'Home':
        panel.cursor.set(0);
        break;
      case 'End':
        panel.cursor.set(Math.max(0, panel.sorted().length - 1));
        break;
      case ' ':
        {
          const entry = panel.sorted()[panel.cursor()];
          if (entry) panel.toggleSelect(entry.name);
          panel.moveCursor(1);
        }
        break;
      case 'Enter':
        this.openAt(panel.cursor());
        return void event.preventDefault();
      case 'Backspace':
        panel.up();
        break;
      case 'F2':
        this.actions.rename(panel);
        break;
      case 'F4':
        void this.actions.edit(panel);
        break;
      case 'F5':
        void this.transfers.copyToOtherPanel(this.side());
        break;
      case 'F7':
        this.actions.mkdir(panel);
        break;
      case 'F8':
      case 'Delete':
        this.actions.delete(panel);
        break;
      default:
        return; // let unhandled keys through
    }
    event.preventDefault();
    this.scrollCursorIntoView();
  }

  private scrollCursorIntoView(): void {
    const row = this.listEl().nativeElement.querySelector(
      `[data-index="${this.panel().cursor()}"]`,
    );
    row?.scrollIntoView({ block: 'nearest' });
  }
}