import crypto from 'node:crypto';
import {
  expandObservedFetchRange,
  extractEventTime,
  itemMatchesTimeWindow,
} from '../event-time-extract.mjs';

function newTimelineId(sourceRef) {
  const hash = crypto.createHash('sha256').update(`timeline-v1|${sourceRef}`).digest('hex');
  return [
    hash.slice(0, 8),
    hash.slice(8, 12),
    `4${hash.slice(13, 16)}`,
    hash.slice(16, 20),
    hash.slice(20, 32),
  ].join('-');
}

function parseUserMessage(row) {
  try {
    return typeof row.user_message_json === 'string'
      ? JSON.parse(row.user_message_json)
      : row.user_message_json;
  } catch {
    return null;
  }
}

function extractText(message) {
  if (!message) return '';
  if (typeof message === 'string') return message.trim();
  if (typeof message.content === 'string') return message.content.trim();
  if (Array.isArray(message.content)) {
    return message.content
      .map((part) => (typeof part === 'string' ? part : part?.text ?? ''))
      .join('')
      .trim();
  }
  if (typeof message.text === 'string') return message.text.trim();
  return '';
}

function scoreTextImportance(text, expandedQueries = []) {
  let score = 0.5;
  const t = String(text ?? '');
  if (/重要|紧急|安排|会议|待办|记得|跟进|截止|确认/.test(t)) score += 0.18;
  for (const q of expandedQueries) {
    if (q && t.includes(q)) score += 0.05;
  }
  return Math.min(0.95, score);
}

function matchesExpanded(text, expandedQueries) {
  if (!expandedQueries?.length) return true;
  return expandedQueries.some((q) => q && text.includes(q));
}

/**
 * @param {import('mysql2/promise').Pool} pool
 * @param {{ userId: string, retrieval: object, time: object, sessionId?: string }} ctx
 */
export async function searchChat(pool, ctx) {
  if (!pool?.query) return [];

  let sql = `
    SELECT id, user_message_json, created_at, agent_session_id
    FROM h5_agent_runs
    WHERE user_id = ? AND created_at >= ? AND created_at < ?`;
  const fetchRange = expandObservedFetchRange(ctx.time, ctx.temporalMode);
  const params = [ctx.userId, new Date(fetchRange.start).getTime(), new Date(fetchRange.end).getTime()];
  if (ctx.sessionId) {
    sql += ' AND agent_session_id = ?';
    params.push(ctx.sessionId);
  }
  sql += ' ORDER BY created_at ASC LIMIT 300';

  const [rows] = await pool.query(sql, params);
  const items = [];
  for (const row of rows) {
    const message = parseUserMessage(row);
    const text = extractText(message);
    if (text.length < 2) continue;
    if (!matchesExpanded(text, ctx.retrieval.expanded_queries) && text.length < 12) continue;
    const observed = new Date(Number(row.created_at)).toISOString();
    const extracted = extractEventTime(text, observed);
    const sourceRef = `chat:run:${row.id}`;
    const item = {
      timeline_item_id: newTimelineId(sourceRef),
      user_id: ctx.userId,
      source: 'chat',
      type: /待办|记得|别忘了|跟进|截止|安排/.test(text) ? 'commitment' : 'mention',
      event_time: extracted.event_time,
      observed_time: observed,
      title: text.slice(0, 80),
      content: text.slice(0, 8192),
      importance: scoreTextImportance(text, ctx.retrieval.expanded_queries),
      confidence: extracted.event_time ? extracted.confidence : 0.88,
      source_ref: sourceRef,
      participants: [],
      status: extracted.status === 'planned' ? 'planned' : 'mentioned',
      metadata: { agent_session_id: row.agent_session_id },
    };
    if (!itemMatchesTimeWindow(item, ctx.time, ctx.temporalMode)) continue;
    items.push(item);
  }
  return items;
}