import { Component, ElementRef, effect, inject, signal, viewChild } from '@angular/core';
import { NgIcon } from '@ng-icons/core';
import { ContextMenuService } from '@core/context-menu.service';
import { I18nService } from '@core/i18n.service';
import { PanelsService, type Workspace } from '@core/panels.service';
import { IS_MAC_CHROME, MOD_LABEL } from '@core/platform';
import { RpcService } from '@core/rpc.service';
import { UpdaterService } from '@core/updater.service';

@Component({
  selector: 'app-tab-bar',
  imports: [NgIcon],
  template: `
    <!-- On macOS this row IS the titlebar (hiddenInset): taller, padded past the
         traffic lights, and draggable. Elsewhere it's a normal compact row. -->
    <div
      class="relative flex items-center gap-0.5 border-b border-border bg-chrome pr-1.5 electrobun-webkit-app-region-drag"
      [class.h-10]="isMacChrome"
      [class.pl-24]="isMacChrome"
      [class.pl-1.5]="!isMacChrome"
      [class.pt-1]="!isMacChrome"
    >
      <div
        #tabScroll
        role="tablist"
        class="flex min-w-0 items-center gap-0.5 overflow-x-auto [scrollbar-width:none] [&::-webkit-scrollbar]:hidden"
      >
      @for (ws of panels.workspaces(); track ws.id; let i = $index) {
        <div
          [attr.data-tab-id]="ws.id"
          class="group relative flex max-w-52 shrink-0 items-center electrobun-webkit-app-region-no-drag"
          [class.bg-accent]="ws.id === panels.activeWorkspaceId()"
          [class.opacity-50]="draggedId() === ws.id"
          [style.box-shadow]="dropIndicatorShadow(i)"
          (contextmenu)="onTabContextMenu($event, ws, i)"
          (mousedown)="onTabMouseDown($event)"
          (auxclick)="onAuxClick($event, ws.id)"
          draggable="true"
          (dragstart)="onDragStart($event, ws.id)"
          (dragover)="onDragOver($event, i)"
          (drop)="onDrop($event, i)"
          (dragend)="onDragEnd()"
        >
          <button
            role="tab"
            [attr.aria-selected]="ws.id === panels.activeWorkspaceId()"
            (click)="panels.setActiveWorkspace(ws.id)"
            class="flex min-w-0 items-center gap-1.5 py-1.5 pr-1 pl-2.5 text-xs"
            [class.text-foreground]="ws.id === panels.activeWorkspaceId()"
            [class.text-muted-foreground]="ws.id !== panels.activeWorkspaceId()"
            [title]="panels.workspaceName(ws)"
          >
            <ng-icon
              [name]="panels.workspaceIsRemote(ws) ? 'tdesignServer' : 'tdesignHardDrive'"
              size="0.85rem"
              class="shrink-0"
              [class.text-primary]="panels.workspaceIsRemote(ws)"
            />
            <span class="truncate">{{ panels.workspaceName(ws) }}</span>
          </button>
          @if (panels.workspaces().length > 1) {
            <button
              (click)="close($event, ws.id)"
              tabindex="-1"
              aria-hidden="true"
              [title]="i18n.t('tabBar.closeTab', { mod: modLabel })"
              class="mr-1 grid size-4 shrink-0 place-items-center text-muted-foreground opacity-0 group-hover:opacity-100 hover:bg-border hover:text-foreground"
            >
              <ng-icon name="tdesignClose" size="0.7rem" />
            </button>
          } @else {
            <span class="mr-1 size-4 shrink-0"></span>
          }
          @if (ws.id === panels.activeWorkspaceId()) {
            <div class="absolute inset-x-0 -bottom-px h-0.5 bg-primary"></div>
          }
        </div>
      }
      </div>
      <button
        (click)="panels.newWorkspace()"
        [title]="i18n.t('tabBar.newTab', { mod: modLabel })"
        class="ml-0.5 grid size-6 place-items-center text-muted-foreground electrobun-webkit-app-region-no-drag hover:bg-accent hover:text-foreground"
      >
        <ng-icon name="tdesignAdd" size=".8rem" />
      </button>

      <div class="flex-1"></div>

      <!-- auto-update tool: one accent pill that announces the update, becomes its
           own progress bar while downloading, then turns into "Restart to apply" -->
      @if (updater.state() !== 'idle' && updater.state() !== 'error') {
        <button
          (click)="onUpdateClick()"
          [disabled]="updater.state() === 'downloading'"
          [title]="i18n.t('tabBar.updateTooltip', { version: updater.version() })"
          class="relative mr-1 grid h-6 place-items-center overflow-hidden px-2.5 text-[0.6875rem] font-medium bg-primary text-primary-foreground electrobun-webkit-app-region-no-drag hover:opacity-90 disabled:cursor-default"
        >
          @if (updater.state() === 'downloading') {
            <span
              class="absolute inset-y-0 left-0 bg-primary-foreground/25 transition-[width] duration-200"
              [style.width.%]="updater.progress()"
            ></span>
          }
          <span class="relative flex items-center gap-1.5">
            @switch (updater.state()) {
              @case ('available') {
                <ng-icon name="tdesignDownload" size=".8rem" />{{ i18n.t('tabBar.update') }}
              }
              @case ('downloading') {
                <ng-icon name="tdesignLoading" size=".8rem" class="animate-spin" />{{ i18n.t('tabBar.updating') }} {{ updater.progress() }}%
              }
              @case ('ready') {
                <ng-icon name="tdesignRefresh" size=".8rem" />{{ i18n.t('tabBar.restartToUpdate') }}
              }
            }
          </span>
        </button>
      }

      <!-- connection manager (own native window) -->
      <button
        (click)="openManager()"
        [title]="i18n.t('tabBar.manageConnections')"
        class="grid h-6 px-2 py-1 place-items-center text-[0.6875rem] text-muted-foreground electrobun-webkit-app-region-no-drag hover:bg-accent hover:text-foreground"
      >
        <!-- <ng-icon name="tdesignSetting" size="0.9rem" /> -->
         {{ i18n.t('tabBar.connections') }}
      </button>

      <!-- settings (own native window) -->
      <button
        (click)="openSettings()"
        [title]="i18n.t('tabBar.options')"
        class="grid size-6 place-items-center text-muted-foreground electrobun-webkit-app-region-no-drag hover:bg-accent hover:text-foreground"
      >
        <ng-icon name="tdesignSetting" size="0.9rem" />
      </button>
    </div>
  `,
})
export class TabBar {
  readonly panels = inject(PanelsService);
  readonly i18n = inject(I18nService);
  readonly updater = inject(UpdaterService);
  private readonly contextMenu = inject(ContextMenuService);
  private readonly rpc = inject(RpcService);
  readonly isMacChrome = IS_MAC_CHROME;
  readonly modLabel = MOD_LABEL;

  // drag & drop reordering
  readonly draggedId = signal<number | null>(null);
  readonly dropTarget = signal<{ index: number; before: boolean } | null>(null);

  private readonly tabScroll = viewChild.required<ElementRef<HTMLDivElement>>('tabScroll');

  constructor() {
    // keep the active tab visible when the strip overflows
    effect(() => {
      const id = this.panels.activeWorkspaceId();
      this.tabScroll()
        .nativeElement.querySelector(`[data-tab-id="${id}"]`)
        ?.scrollIntoView({ inline: 'nearest', block: 'nearest' });
    });
  }

  close(event: MouseEvent, id: number): void {
    event.stopPropagation();
    this.panels.closeWorkspace(id);
  }

  /**
   * Middle-click closes the tab, as in browsers. `auxclick` also fires for the
   * right button, hence the button check; the last tab is refused by
   * closeWorkspace itself.
   */
  onAuxClick(event: MouseEvent, id: number): void {
    if (event.button !== 1) return;
    event.preventDefault();
    this.close(event, id);
  }

  /** A middle press over the scrollable strip would start WebView2's autoscroll. */
  onTabMouseDown(event: MouseEvent): void {
    if (event.button === 1) event.preventDefault();
  }

  /**
   * Right-click a tab. The menu targets THIS tab, not the active one — its
   * actions all carry the id — so right-clicking a background tab does not
   * yank focus to it first, the way Explorer and every browser behave.
   */
  onTabContextMenu(event: MouseEvent, workspace: Workspace, index: number): void {
    event.preventDefault();
    this.contextMenu.open(
      event,
      this.contextMenu.tabItems({
        id: workspace.id,
        index,
        tabCount: this.panels.workspaces().length,
        isRemote: this.panels.workspaceIsRemote(workspace),
      }),
    );
  }

  openManager(): void {
    void this.rpc.request.openConnectionManager({});
  }

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

  /** Update pill: first click downloads, second click (when ready) applies + relaunches. */
  onUpdateClick(): void {
    const state = this.updater.state();
    if (state === 'available') void this.updater.download();
    else if (state === 'ready') this.updater.apply();
  }

  /** Insertion line at the drop position (inset shadow: no layout shift). */
  dropIndicatorShadow(index: number): string | null {
    const target = this.dropTarget();
    if (!target || target.index !== index || this.draggedId() === null) return null;
    return target.before
      ? 'inset 2px 0 0 var(--primary)'
      : 'inset -2px 0 0 var(--primary)';
  }

  onDragStart(event: DragEvent, id: number): void {
    this.draggedId.set(id);
    // WebKit refuses to start a drag without data
    event.dataTransfer?.setData('text/plain', String(id));
    if (event.dataTransfer) event.dataTransfer.effectAllowed = 'move';
  }

  onDragOver(event: DragEvent, index: number): void {
    if (this.draggedId() === null) return;
    event.preventDefault();
    if (event.dataTransfer) event.dataTransfer.dropEffect = 'move';
    const el = event.currentTarget as HTMLElement;
    const before = event.clientX < el.getBoundingClientRect().left + el.offsetWidth / 2;
    this.dropTarget.set({ index, before });
  }

  onDrop(event: DragEvent, index: number): void {
    event.preventDefault();
    const id = this.draggedId();
    const target = this.dropTarget();
    this.onDragEnd();
    if (id === null || !target) return;
    const list = this.panels.workspaces();
    const fromIndex = list.findIndex((w) => w.id === id);
    if (fromIndex < 0) return;
    let toIndex = target.before ? index : index + 1;
    if (fromIndex < toIndex) toIndex--; // account for removal before insert
    if (toIndex !== fromIndex) this.panels.moveWorkspace(id, toIndex);
  }

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