import crypto from 'node:crypto';
import { buildChatSkillPrompt, SCHEDULED_TASK_AUTOMATION_SKILL_NAME } from './chat-skills.mjs';
import { localDateLabel } from './schedule-time.mjs';

function messageText(message) {
  if (typeof message?.content === 'string') return message.content.trim();
  if (!Array.isArray(message?.content)) return '';
  return message.content
    .filter((item) => item?.type === 'text')
    .map((item) => String(item?.text ?? '').trim())
    .filter(Boolean)
    .join('\n');
}

export function buildScheduledTaskExecutionPrompt(task, {
  now = Date.now(),
  timezone = task?.timezone ?? 'Asia/Shanghai',
} = {}) {
  const dateLabel = localDateLabel(now, timezone);
  const body = [
    '【定时任务自动执行 Scheduled Automation】',
    `任务标题：${task.title}`,
    `执行日期：${dateLabel}`,
    `任务要求：${task.taskSpec}`,
    '执行约束：',
    '- 这是系统自动触发的定时任务，请直接完成可交付结果，不要反问用户。',
    '- 若需要生成页面，必须先 load_skill → static-page-publish，再 write_file 到 public/*.html，并给出正式可访问 URL。',
    '- 若只需摘要/文本，给出完整中文结果摘要。',
    '- 完成后在回复中明确写出交付结果（链接或摘要）。',
  ].join('\n');
  const prefix = buildChatSkillPrompt(
    'scheduled-task-automation',
    SCHEDULED_TASK_AUTOMATION_SKILL_NAME,
  );
  return {
    role: 'user',
    content: [{ type: 'text', text: `${prefix}${body}` }],
    metadata: {
      displayText: `定时任务：${task.title}`,
      userVisible: false,
      agentVisible: true,
      memindScheduledTask: {
        taskId: task.id,
        recurrence: task.recurrence,
        automated: true,
      },
    },
  };
}

export function extractScheduledTaskDeliveryText(messages, task) {
  const lastAssistant = [...(Array.isArray(messages) ? messages : [])]
    .reverse()
    .find((message) => message?.role === 'assistant');
  const text = messageText(lastAssistant);
  if (text) return text.trim();
  return `定时任务「${task.title}」已执行完成。`;
}

export function formatScheduledTaskDeliveryMessage(task, deliveryText) {
  const header = `定时任务完成：${task.title}`;
  const body = String(deliveryText ?? '').trim() || '任务已执行，请前往 MindSpace 查看结果。';
  return `${header}\n\n${body}`.trim();
}

export async function executeScheduledTask(task, {
  userAuth,
  tkmindProxy,
  sessionSnapshotService = null,
  timeoutMs = 15 * 60 * 1000,
  logger = console,
} = {}) {
  if (!task?.userId) throw new Error('缺少 task.userId');
  if (!userAuth || typeof userAuth.canUseChat !== 'function') {
    throw new Error('缺少 userAuth.canUseChat');
  }
  if (
    !tkmindProxy
    || typeof tkmindProxy.startSessionForUser !== 'function'
    || typeof tkmindProxy.submitSessionReplyAndAwaitFinishForUser !== 'function'
  ) {
    throw new Error('缺少 tkmindProxy 会话执行能力');
  }

  const gate = await userAuth.canUseChat(task.userId);
  if (!gate?.ok) {
    const err = new Error(gate?.message ?? '当前账户无法执行定时任务');
    err.code = gate?.code ?? 'CHAT_NOT_ALLOWED';
    throw err;
  }

  const requestId = crypto.randomUUID();
  const started = await tkmindProxy.startSessionForUser(task.userId, {
    origin: 'h5',
  });
  const sessionId = started?.id ?? started?.sessionId;
  if (!sessionId) throw new Error('创建定时任务会话失败');

  const userMessage = buildScheduledTaskExecutionPrompt(task);
  logger.info?.('[ScheduledTask] executing', {
    taskId: task.id,
    userId: task.userId,
    sessionId,
    requestId,
  });

  await tkmindProxy.submitSessionReplyAndAwaitFinishForUser(
    task.userId,
    sessionId,
    requestId,
    userMessage,
    { timeoutMs },
  );

  let messages = [];
  if (typeof sessionSnapshotService?.refresh === 'function') {
    const refreshed = await sessionSnapshotService.refresh(sessionId).catch(() => null);
    messages = refreshed?.messages ?? refreshed?.conversation?.messages ?? [];
  } else if (typeof sessionSnapshotService?.get === 'function') {
    const snapshot = await sessionSnapshotService.get(sessionId).catch(() => null);
    messages = snapshot?.messages ?? snapshot?.conversation?.messages ?? [];
  }

  const deliveryText = extractScheduledTaskDeliveryText(messages, task);
  return {
    sessionId,
    requestId,
    deliveryText,
    messages,
  };
}