import crypto from 'node:crypto';
import {
  expandObservedFetchRange,
  extractEventTime,
  itemMatchesTimeWindow,
} from '../event-time-extract.mjs';
import mysql from 'mysql2/promise';

let meinputPool = null;

function getMeinputPool() {
  const url = process.env.MEINPUT_DATABASE_URL ?? '';
  if (!url) return null;
  if (!meinputPool) {
    meinputPool = mysql.createPool({ uri: url, waitForConnections: true, connectionLimit: 4 });
  }
  return meinputPool;
}

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 scoreTextImportance(text, expandedQueries = []) {
  let score = 0.45;
  const t = String(text ?? '');
  if (t.length >= 20) score += 0.08;
  if (/重要|紧急|必须|截止|会议|安排|明天|今天|项目/.test(t)) score += 0.15;
  for (const q of expandedQueries) {
    if (q && t.includes(q)) score += 0.05;
  }
  return Math.min(0.95, score);
}

function envelopeToTimelineItem(envelope, expandedQueries, temporalMode, time) {
  const payload = envelope.payload ?? {};
  const text = String(payload.text ?? '').trim();
  if (!text) return null;
  const observed = envelope.occurred_at;
  const extracted = extractEventTime(text, observed);
  const appName = payload.context?.app ?? null;
  const appBundle = payload.context?.app_bundle_id ?? null;
  const sourceRef = `meinput:segment:${envelope.evidence_id}`;
  const item = {
    timeline_item_id: newTimelineId(sourceRef),
    user_id: envelope.user_id,
    source: 'meinput',
    type: /待办|记得|别忘了|跟进|截止/.test(text) ? 'todo' : 'mention',
    event_time: extracted.event_time,
    observed_time: observed,
    title: text.slice(0, 80),
    content: text.slice(0, 8192),
    importance: scoreTextImportance(text, expandedQueries),
    confidence: extracted.event_time ? extracted.confidence : 0.92,
    source_ref: sourceRef,
    participants: [],
    status: extracted.status === 'planned' ? 'planned' : 'mentioned',
    app_name: appName,
    app_bundle_id: appBundle,
  };
  if (time && !itemMatchesTimeWindow(item, time, temporalMode)) return null;
  return item;
}

async function fetchViaHttp(ctx) {
  const base = process.env.MEINPUT_BASE_URL ?? 'https://input.tkmind.cn';
  const username = process.env.MEINPUT_USERNAME ?? 'admin';
  const password = process.env.MEINPUT_PASSWORD ?? '';
  if (!password) return [];

  const loginRes = await fetch(`${base}/v1/auth/login`, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ username, password }),
  });
  const login = await loginRes.json();
  if (!loginRes.ok || login.user_id !== ctx.userId) {
    return [];
  }

  const url = new URL(`${base}/v1/evidence/export`);
  url.searchParams.set('limit', '200');
  url.searchParams.set('since', ctx.time.mention_range.start);
  url.searchParams.set('until', ctx.time.mention_range.end);
  const res = await fetch(url, { headers: { authorization: `Bearer ${login.access_token}` } });
  const data = await res.json();
  if (!res.ok) return [];
  return (data.items ?? [])
    .map((item) =>
      envelopeToTimelineItem(
        item,
        ctx.retrieval.expanded_queries,
        ctx.temporalMode,
        ctx.time,
      ),
    )
    .filter(Boolean);
}

async function fetchViaDb(ctx) {
  const pool = getMeinputPool();
  if (!pool) return null;
  const fetchRange = expandObservedFetchRange(ctx.time, ctx.temporalMode);
  const [rows] = await pool.query(
    `SELECT event_id, text, app_name, app_bundle_id, created_at
     FROM mi_input_events
     WHERE user_id = ? AND privacy_level = 'normal'
       AND created_at >= ? AND created_at < ?
     ORDER BY created_at ASC
     LIMIT 800`,
    [
      ctx.userId,
      fetchRange.start.slice(0, 23).replace('T', ' '),
      fetchRange.end.slice(0, 23).replace('T', ' '),
    ],
  );
  return rows
    .map((row) => {
      const observed =
        row.created_at instanceof Date ? row.created_at.toISOString() : new Date(row.created_at).toISOString();
      const envelope = {
        evidence_id: row.event_id,
        user_id: ctx.userId,
        occurred_at: observed,
        payload: {
          text: row.text,
          context: { app: row.app_name, app_bundle_id: row.app_bundle_id },
        },
      };
      return envelopeToTimelineItem(
        envelope,
        ctx.retrieval.expanded_queries,
        ctx.temporalMode,
        ctx.time,
      );
    })
    .filter(Boolean);
}

/**
 * Rain 模式：按精确时间区间全量拉取 MeInput 原始记录（不过滤、不排序）。
 * @param {{ userId: string, range: { start: string, end: string } }} input
 */
export async function fetchMeinputRangeFull(input) {
  const userId = String(input.userId ?? '').trim();
  const start = String(input.range?.start ?? '').trim();
  const end = String(input.range?.end ?? '').trim();
  if (!userId || !start || !end) return [];

  const pool = getMeinputPool();
  if (pool) {
    const [rows] = await pool.query(
      `SELECT event_id, text, app_name, app_bundle_id, created_at
       FROM mi_input_events
       WHERE user_id = ? AND privacy_level = 'normal'
         AND created_at >= ? AND created_at < ?
       ORDER BY created_at ASC`,
      [userId, start.slice(0, 23).replace('T', ' '), end.slice(0, 23).replace('T', ' ')],
    );
    return rows.map((row) => ({
      event_id: row.event_id,
      text: row.text,
      app_name: row.app_name,
      app_bundle_id: row.app_bundle_id,
      created_at:
        row.created_at instanceof Date ? row.created_at.toISOString() : new Date(row.created_at).toISOString(),
    }));
  }

  const base = process.env.MEINPUT_BASE_URL ?? 'https://input.tkmind.cn';
  const username = process.env.MEINPUT_USERNAME ?? 'admin';
  const password = process.env.MEINPUT_PASSWORD ?? '';
  if (!password) return [];

  const loginRes = await fetch(`${base}/v1/auth/login`, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ username, password }),
  });
  const login = await loginRes.json();
  if (!loginRes.ok || login.user_id !== userId) return [];

  const url = new URL(`${base}/v1/evidence/export`);
  url.searchParams.set('limit', '10000');
  url.searchParams.set('since', start);
  url.searchParams.set('until', end);
  const res = await fetch(url, { headers: { authorization: `Bearer ${login.access_token}` } });
  const data = await res.json();
  if (!res.ok) return [];
  return (data.items ?? []).map((item) => ({
    event_id: item.evidence_id ?? item.event_id,
    text: item.payload?.text ?? item.text ?? '',
    app_name: item.payload?.context?.app ?? item.app_name ?? null,
    app_bundle_id: item.payload?.context?.app_bundle_id ?? item.app_bundle_id ?? null,
    created_at: item.occurred_at ?? item.created_at,
  }));
}

/**
 * @param {{ userId: string, retrieval: object, time: object, temporalMode: string }} ctx
 */
export async function searchMeinput(ctx) {
  const dbItems = await fetchViaDb(ctx);
  if (dbItems !== null) return dbItems;
  return fetchViaHttp(ctx);
}