import { realpath } from 'node:fs/promises';
import type { IncomingMessage, ServerResponse } from 'node:http';
import type { AgentBrowserBounds, AgentBrowserFaultShape } from '../../../shared/agent-browser';
import { normalizeProjectPath } from '../../opencode/project-store';
import type { HostApiContext } from '../context';
import { hasRendererCapability } from '../renderer-capability';
import { parseJsonBody, sendJson } from '../route-utils';

type AgentBrowserBody = {
  project_path?: unknown;
  url?: unknown;
  action?: unknown;
  visible?: unknown;
  bounds?: unknown;
  method?: unknown;
  params?: unknown;
  session_ref?: unknown;
  timeout_ms?: unknown;
  after?: unknown;
  methods?: unknown;
  limit?: unknown;
  wait_ms?: unknown;
  handle?: unknown;
  offset?: unknown;
  max_bytes?: unknown;
};

class AgentBrowserRouteError extends Error {
  constructor(
    readonly code: AgentBrowserFaultShape['code'],
    message: string,
    readonly status = 400,
  ) {
    super(message);
  }
}

function nonEmptyString(value: unknown): string | undefined {
  return typeof value === 'string' && value.trim() ? value.trim() : undefined;
}

function finiteInteger(value: unknown): number | undefined {
  return typeof value === 'number' && Number.isFinite(value)
    ? Math.trunc(value)
    : undefined;
}

function parseBounds(value: unknown): AgentBrowserBounds | undefined {
  if (!value || typeof value !== 'object' || Array.isArray(value)) return undefined;
  const record = value as Record<string, unknown>;
  const x = finiteInteger(record.x);
  const y = finiteInteger(record.y);
  const width = finiteInteger(record.width);
  const height = finiteInteger(record.height);
  if (x === undefined || y === undefined || width === undefined || height === undefined) {
    throw new AgentBrowserRouteError('INVALID_REQUEST', '浏览器区域坐标不完整。');
  }
  if (width < 1 || height < 1) {
    throw new AgentBrowserRouteError('VIEWPORT_NOT_READY', '浏览器区域尚未准备好。');
  }
  return { x, y, width, height };
}

function parseStringArray(value: unknown): string[] | undefined {
  if (value === undefined) return undefined;
  if (!Array.isArray(value) || value.some((item) => typeof item !== 'string')) {
    throw new AgentBrowserRouteError('INVALID_REQUEST', 'CDP 事件过滤器格式无效。');
  }
  return value.map((item) => item.trim()).filter(Boolean);
}

async function resolveActiveProject(ctx: HostApiContext, requestedPath?: unknown) {
  const activeProject = await ctx.opencodeProjectStore.getActiveProject();
  if (!activeProject) {
    throw new AgentBrowserRouteError('PROJECT_NOT_ACTIVE', '请先打开一个项目。', 409);
  }

  let activeRealPath: string;
  try {
    activeRealPath = await realpath(activeProject.path);
  } catch {
    throw new AgentBrowserRouteError('PROJECT_NOT_ACTIVE', '当前项目目录不可用。', 409);
  }

  const requested = nonEmptyString(requestedPath);
  if (!requested) {
    throw new AgentBrowserRouteError('INVALID_REQUEST', '缺少当前项目路径。');
  }
  let requestedRealPath: string;
  try {
    requestedRealPath = await realpath(requested);
  } catch {
    throw new AgentBrowserRouteError('PROJECT_MISMATCH', '请求的项目目录不可用。', 403);
  }
  if (normalizeProjectPath(requestedRealPath) !== normalizeProjectPath(activeRealPath)) {
    throw new AgentBrowserRouteError('PROJECT_MISMATCH', '智能体只能调试当前项目。', 403);
  }

  return {
    ...activeProject,
    path: activeRealPath,
  };
}

async function ensureProjectStillActive(
  ctx: HostApiContext,
  project: { id: string; path: string },
): Promise<void> {
  const activeProject = await ctx.opencodeProjectStore.getActiveProject();
  let activeRealPath: string | null = null;
  if (activeProject?.id === project.id) {
    try {
      activeRealPath = await realpath(activeProject.path);
    } catch {
      activeRealPath = null;
    }
  }
  if (
    activeProject?.id === project.id
    && activeRealPath
    && normalizeProjectPath(activeRealPath) === normalizeProjectPath(project.path)
  ) {
    return;
  }
  try {
    await ctx.agentBrowser?.close(project.path);
  } catch {
    // A new project's browser may already own the module; never close it.
  }
  throw new AgentBrowserRouteError(
    'PROJECT_MISMATCH',
    '项目已切换，本次浏览器操作已取消。',
    403,
  );
}

function requireService(ctx: HostApiContext) {
  if (!ctx.agentBrowser) {
    throw new AgentBrowserRouteError('CLOSED', '开发浏览器尚未初始化。', 503);
  }
  return ctx.agentBrowser;
}

function requireRendererPresentation(req: IncomingMessage): void {
  if (!hasRendererCapability(req)) {
    throw new AgentBrowserRouteError(
      'TARGET_DENIED',
      '浏览器显示区域只能由 Makelore 界面控制。',
      403,
    );
  }
}

function emitState(ctx: HostApiContext, eventName: 'agent-browser:show' | 'agent-browser:state', payload: unknown): void {
  ctx.eventBus.emit(eventName, payload);
  const webContents = ctx.mainWindow?.webContents;
  if (webContents && !webContents.isDestroyed()) {
    webContents.send(eventName, payload);
  }
}

function faultFrom(error: unknown): AgentBrowserFaultShape | null {
  if (!error || typeof error !== 'object') return null;
  const record = error as Partial<AgentBrowserFaultShape>;
  if (typeof record.code !== 'string' || typeof record.message !== 'string') return null;
  return {
    code: record.code,
    message: record.message,
    retryable: record.retryable === true,
    ...(typeof record.generation === 'number' ? { generation: record.generation } : {}),
    ...(record.outcome === 'unknown' ? { outcome: 'unknown' } : {}),
  };
}

function faultStatus(code: AgentBrowserFaultShape['code']): number {
  if (code === 'PROJECT_MISMATCH' || code === 'TARGET_DENIED' || code === 'CDP_METHOD_BLOCKED') return 403;
  if (code === 'BROWSER_NOT_OPEN' || code === 'PAYLOAD_NOT_FOUND' || code === 'TARGET_GONE') return 404;
  if (code === 'CURSOR_EXPIRED') return 410;
  if (code === 'DEVTOOLS_CONFLICT' || code === 'DEBUGGER_BUSY' || code === 'PROJECT_NOT_ACTIVE') return 409;
  if (code === 'CDP_TIMEOUT') return 504;
  if (code === 'ATTACH_FAILED' || code === 'RENDERER_CRASHED' || code === 'CLOSED') return 503;
  return 400;
}

async function readBody(req: IncomingMessage): Promise<AgentBrowserBody> {
  return await parseJsonBody<AgentBrowserBody>(req);
}

export async function handleAgentBrowserRoutes(
  req: IncomingMessage,
  res: ServerResponse,
  url: URL,
  ctx: HostApiContext,
): Promise<boolean> {
  if (!url.pathname.startsWith('/api/agent-browser')) return false;

  try {
    const service = requireService(ctx);

    if (url.pathname === '/api/agent-browser/state' && req.method === 'GET') {
      const project = await resolveActiveProject(ctx, url.searchParams.get('project_path'));
      const browser = await service.getSnapshot(project.path);
      await ensureProjectStillActive(ctx, project);
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    if (url.pathname === '/api/agent-browser/open' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const rendererPresentation = hasRendererCapability(req);
      if (body.bounds !== undefined && !rendererPresentation) {
        requireRendererPresentation(req);
      }
      const targetUrl = nonEmptyString(body.url);
      if (!targetUrl) throw new AgentBrowserRouteError('INVALID_URL', '请输入要打开的网页地址。');
      const browser = await service.open({
        projectId: project.id,
        projectPath: project.path,
        url: targetUrl,
        bounds: parseBounds(body.bounds),
        visible: rendererPresentation && body.visible !== false,
      });
      await ensureProjectStillActive(ctx, project);
      emitState(ctx, 'agent-browser:show', browser);
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    if (url.pathname === '/api/agent-browser/present' && req.method === 'POST') {
      requireRendererPresentation(req);
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const browser = await service.present({
        projectPath: project.path,
        visible: body.visible === true,
        bounds: parseBounds(body.bounds),
      });
      await ensureProjectStillActive(ctx, project);
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    if (url.pathname === '/api/agent-browser/navigate' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const action = nonEmptyString(body.action);
      if (action !== 'url' && action !== 'back' && action !== 'forward' && action !== 'reload') {
        throw new AgentBrowserRouteError('INVALID_REQUEST', '浏览器导航动作无效。');
      }
      const browser = await service.navigate({
        projectPath: project.path,
        action,
        url: nonEmptyString(body.url),
      });
      await ensureProjectStillActive(ctx, project);
      emitState(ctx, 'agent-browser:state', browser);
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    if (url.pathname === '/api/agent-browser/cdp/send' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const method = nonEmptyString(body.method);
      if (!method) throw new AgentBrowserRouteError('INVALID_REQUEST', '缺少 CDP method。');
      const params = body.params === undefined
        ? undefined
        : body.params && typeof body.params === 'object' && !Array.isArray(body.params)
          ? body.params as Record<string, unknown>
          : (() => {
              throw new AgentBrowserRouteError('INVALID_REQUEST', 'CDP params 必须是对象。');
            })();
      const result = await service.sendCdp({
        projectPath: project.path,
        method,
        params,
        sessionRef: nonEmptyString(body.session_ref),
        timeoutMs: finiteInteger(body.timeout_ms),
      });
      await ensureProjectStillActive(ctx, project);
      sendJson(res, 200, { success: true, result });
      return true;
    }

    if (url.pathname === '/api/agent-browser/cdp/events' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const page = await service.readEvents({
        projectPath: project.path,
        after: finiteInteger(body.after),
        methods: parseStringArray(body.methods),
        limit: finiteInteger(body.limit),
        waitMs: finiteInteger(body.wait_ms),
      });
      await ensureProjectStillActive(ctx, project);
      sendJson(res, 200, { success: true, page });
      return true;
    }

    if (url.pathname === '/api/agent-browser/payload/read' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const handle = nonEmptyString(body.handle);
      if (!handle) throw new AgentBrowserRouteError('INVALID_REQUEST', '缺少 payload handle。');
      const chunk = await service.readPayload({
        projectPath: project.path,
        handle,
        offset: finiteInteger(body.offset),
        maxBytes: finiteInteger(body.max_bytes),
      });
      await ensureProjectStillActive(ctx, project);
      sendJson(res, 200, { success: true, chunk });
      return true;
    }

    if (url.pathname === '/api/agent-browser/close' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const browser = await service.close(project.path);
      await ensureProjectStillActive(ctx, project);
      emitState(ctx, 'agent-browser:state', {
        ...browser,
        projectId: project.id,
        projectPath: project.path,
      });
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    if (url.pathname === '/api/agent-browser/reset-profile' && req.method === 'POST') {
      const body = await readBody(req);
      const project = await resolveActiveProject(ctx, body.project_path);
      const browser = await service.resetProfile(project.path);
      await ensureProjectStillActive(ctx, project);
      emitState(ctx, 'agent-browser:state', {
        ...browser,
        projectId: project.id,
        projectPath: project.path,
      });
      sendJson(res, 200, { success: true, browser });
      return true;
    }

    sendJson(res, 404, {
      success: false,
      code: 'INVALID_REQUEST',
      error: `No Agent Browser route for ${req.method} ${url.pathname}`,
    });
    return true;
  } catch (error) {
    const routeError = error instanceof AgentBrowserRouteError ? error : null;
    const fault = routeError
      ? {
          code: routeError.code,
          message: routeError.message,
          retryable: false,
        }
      : faultFrom(error);
    if (fault) {
      sendJson(res, routeError?.status ?? faultStatus(fault.code), {
        success: false,
        error: fault.message,
        ...fault,
      });
      return true;
    }
    throw error;
  }
}