import { useState } from 'react';
import { createPortal } from 'react-dom';
import {
  LoaderCircle,
  Pencil,
  PanelRightClose,
  PanelRightOpen,
  RotateCcw,
  Square,
} from 'lucide-react';
import { Button } from '@/components/ui/button';
import { CodingConversationRenameDialog } from './CodingConversationRenameDialog';
import { cn } from '@/lib/utils';
import { useSettingsStore } from '@/stores/settings';
import { TITLEBAR_LOGO_WIDTH, WINDOWS_TITLEBAR_CONTROLS_WIDTH } from '@/components/layout/titlebar-metrics';
import type { ConversationSnapshot } from '@/types/coding-conversation';
import type { CodingConversationMetadata } from '@/types/coding-project';

const WORKSPACE_COLUMN_WIDTH = 256;

interface LocalActionError {
  message: string;
  backendCode?: string;
  startedGeneration: number;
  startedSeq: number;
}

function localActionError(
  error: unknown,
  startedGeneration: number,
  startedSeq: number,
): LocalActionError {
  const details = error && typeof error === 'object'
    && 'details' in error
    && error.details
    && typeof error.details === 'object'
      ? error.details as { backendCode?: unknown }
      : null;
  return {
    message: error instanceof Error ? error.message : String(error),
    ...(typeof details?.backendCode === 'string' ? { backendCode: details.backendCode } : {}),
    startedGeneration,
    startedSeq,
  };
}

export function CodingConversationHeader({
  conversation,
  snapshot,
  onRename,
  onAbort,
  onRecover,
  browserOpen = false,
  browserAvailable = false,
  onToggleBrowser,
}: {
  conversation: CodingConversationMetadata | null;
  snapshot: ConversationSnapshot | null;
  onRename(title: string): Promise<void>;
  onAbort(): Promise<void>;
  onRecover(): Promise<void>;
  browserOpen?: boolean;
  browserAvailable?: boolean;
  onToggleBrowser?(): void;
}) {
  const sidebarCollapsed = useSettingsStore((state) => state.sidebarCollapsed);
  const [busyAction, setBusyAction] = useState<string | null>(null);
  const [actionError, setActionError] = useState<LocalActionError | null>(null);
  const [renameOpen, setRenameOpen] = useState(false);

  const runStatus = snapshot?.run.status ?? 'preparing';
  const running = ['queued', 'running', 'retrying', 'compacting', 'aborting'].includes(runStatus);
  const recoverable = Boolean(snapshot?.run.error?.recoverable || snapshot?.worker.error?.recoverable);
  const runtimeErrorCode = snapshot?.run.error?.code ?? snapshot?.worker.error?.code;
  const cursorAdvancedPastAction = Boolean(actionError && snapshot && (
    snapshot.cursor.workerGeneration > actionError.startedGeneration
    || (snapshot.cursor.workerGeneration === actionError.startedGeneration
      && snapshot.cursor.seq > actionError.startedSeq)
  ));
  const visibleActionError = actionError?.backendCode === 'CODING_REQUEST_UNCERTAIN'
    && !running
    && runtimeErrorCode !== 'CODING_REQUEST_UNCERTAIN'
    && cursorAdvancedPastAction
    ? null
    : actionError;
  const platform = typeof window === 'undefined' ? undefined : window.electron?.platform;
  const hasCustomTitleBar = platform === 'darwin' || platform === 'win32';

  const perform = (key: string, action: () => Promise<void>) => {
    if (busyAction || !conversation) return;
    const startedGeneration = snapshot?.cursor.workerGeneration ?? 0;
    const startedSeq = snapshot?.cursor.seq ?? 0;
    setBusyAction(key);
    setActionError(null);
    void action()
      .catch((error) => setActionError(localActionError(error, startedGeneration, startedSeq)))
      .finally(() => setBusyAction((current) => current === key ? null : current));
  };

  const iconButtonClass = 'no-drag h-8 w-8 shrink-0 rounded-md p-0';
  const header = (
    <header
      className={cn(
        'drag-region flex h-10 min-w-0 items-center gap-1 border-b border-border/80 px-3',
        hasCustomTitleBar ? 'bg-transparent' : 'bg-background',
        platform === 'darwin' && 'pr-40',
      )}
      data-testid="coding-conversation-header"
    >
      <div className="flex min-w-0 flex-1 items-center">
        <button
          type="button"
          className="no-drag group flex max-w-full items-center gap-1.5 rounded-md text-left"
          disabled={!conversation}
          onClick={() => {
            setRenameOpen(true);
          }}
        >
          <span className="truncate text-sm font-semibold">{conversation?.title ?? '新对话'}</span>
          <Pencil className="h-3 w-3 shrink-0 text-muted-foreground opacity-0 transition-opacity group-hover:opacity-100" aria-hidden="true" />
        </button>
      </div>

      {onToggleBrowser ? (
        <Button
          type="button"
          variant="ghost"
          className={iconButtonClass}
          disabled={!browserAvailable}
          aria-label={browserOpen ? '关闭开发浏览器' : '打开开发浏览器'}
          aria-pressed={browserOpen}
          title={browserOpen ? '关闭开发浏览器' : '打开开发浏览器'}
          onClick={onToggleBrowser}
        >
          {browserOpen
            ? <PanelRightClose className="h-4 w-4" aria-hidden="true" />
            : <PanelRightOpen className="h-4 w-4" aria-hidden="true" />}
        </Button>
      ) : null}

      {running && runStatus !== 'aborting' && (
        <Button
          type="button"
          variant="outline"
          className={iconButtonClass}
          disabled={Boolean(busyAction) || !conversation}
          aria-label="中止"
          title="中止"
          onClick={() => perform('abort', onAbort)}
        >
          {busyAction === 'abort'
            ? <LoaderCircle className="h-4 w-4 animate-spin" aria-hidden="true" />
            : <Square className="h-3.5 w-3.5" aria-hidden="true" />}
        </Button>
      )}
      {recoverable && (
        <Button
          type="button"
          variant="ghost"
          className={iconButtonClass}
          disabled={Boolean(busyAction)}
          aria-label="恢复"
          title="恢复"
          onClick={() => perform('recover', onRecover)}
        >
          <RotateCcw className="h-3.5 w-3.5" aria-hidden="true" />
        </Button>
      )}
    </header>
  );

  return (
    <>
      {hasCustomTitleBar && typeof document !== 'undefined'
        ? createPortal(
            <div
              className="pointer-events-none fixed right-0 top-0 z-[80] h-10"
              data-testid="coding-conversation-header-titlebar"
              style={{
                left: `${sidebarCollapsed ? WORKSPACE_COLUMN_WIDTH : WORKSPACE_COLUMN_WIDTH * 2}px`,
                // Keep both actions and their hit area outside the product chrome.
                right: platform === 'win32' ? TITLEBAR_LOGO_WIDTH + WINDOWS_TITLEBAR_CONTROLS_WIDTH : 0,
              }}
            >
              <div className="pointer-events-auto h-full">{header}</div>
            </div>,
            document.body,
          )
        : header}

      {visibleActionError && (
        <p className="shrink-0 border-b border-destructive/10 bg-destructive/5 px-5 py-2 text-xs text-destructive" role="alert">
          {visibleActionError.message}
        </p>
      )}

      {renameOpen && conversation && <CodingConversationRenameDialog
        title={conversation.title} onSave={onRename} onClose={() => setRenameOpen(false)} />}
    </>
  );
}