# -*- coding: utf-8 -*-
"""ziwei-power SQLite 数据库操作层"""

import sqlite3
import json
import os
from datetime import datetime

DB_DIR = os.path.join(os.path.expanduser('~'), '.workbuddy', 'data', 'ziwei-power')
os.makedirs(DB_DIR, exist_ok=True)
DB_PATH = os.path.join(DB_DIR, 'ziwei_power.db')

# 当前数据库 schema 版本 —— 改表结构时必须 +1 并补迁移逻辑
CURRENT_SCHEMA_VERSION = 2


def get_conn():
    conn = sqlite3.connect(DB_PATH)
    conn.row_factory = sqlite3.Row
    return conn


def _get_schema_version(conn):
    """读取当前数据库的 schema 版本，无表时返回 0"""
    conn.execute('''
        CREATE TABLE IF NOT EXISTS schema_version (
            version INTEGER NOT NULL
        )
    ''')
    row = conn.execute('SELECT version FROM schema_version').fetchone()
    return row['version'] if row else 0


def _set_schema_version(conn, version):
    """写入 schema 版本"""
    conn.execute('DELETE FROM schema_version')
    conn.execute('INSERT INTO schema_version (version) VALUES (?)', (version,))


def init_db():
    """初始化数据库表 & 自动迁移"""
    conn = get_conn()
    current = _get_schema_version(conn)

    # ── 迁移步骤（按版本号递增）────────────────────────
    if current < 1:
        # v1: 初始表结构
        conn.execute('''
            CREATE TABLE IF NOT EXISTS checkins (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                date TEXT UNIQUE NOT NULL,
                data TEXT NOT NULL,
                created_at TEXT NOT NULL,
                updated_at TEXT NOT NULL
            )
        ''')

    if current < 2:
        # v2: 日打卡 → 周打卡
        # 备份旧表 → 聚合 → 新建周表
        existing = conn.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='checkins'").fetchone()
        if existing:
            # 检查是否已有备份表（幂等）
            backup_exists = conn.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='checkins_daily_backup'").fetchone()
            if not backup_exists:
                conn.execute("ALTER TABLE checkins RENAME TO checkins_daily_backup")
            # 重新创建 checkins 表（结构不变，date 语义变为周号）
            conn.execute('''
                CREATE TABLE IF NOT EXISTS checkins (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    date TEXT UNIQUE NOT NULL,
                    data TEXT NOT NULL,
                    created_at TEXT NOT NULL,
                    updated_at TEXT NOT NULL
                )
            ''')
            # 聚合日数据到周
            if not backup_exists:
                _aggregate_daily_to_weekly(conn)

    # ── 将来加字段/改表在此扩展 ──
    # if current < 2:
    #     conn.execute('ALTER TABLE checkins ADD COLUMN tags TEXT DEFAULT ""')
    #     # 可选：对已有行做数据补全
    #     conn.execute("UPDATE checkins SET tags = '[]' WHERE tags IS NULL")

    # ── 写入最新版本号 ──
    _set_schema_version(conn, CURRENT_SCHEMA_VERSION)
    conn.commit()
    conn.close()


def get_checkin(date_str):
    """获取某天的打卡记录，返回 dict 或 None"""
    conn = get_conn()
    row = conn.execute('SELECT * FROM checkins WHERE date = ?', (date_str,)).fetchone()
    conn.close()
    if row:
        return {
            'id': row['id'],
            'date': row['date'],
            'data': json.loads(row['data']),
            'created_at': row['created_at'],
            'updated_at': row['updated_at']
        }
    return None


def save_checkin(date_str, data_dict):
    """保存或更新打卡记录"""
    now = datetime.now().isoformat()
    conn = get_conn()
    existing = conn.execute('SELECT id FROM checkins WHERE date = ?', (date_str,)).fetchone()
    json_data = json.dumps(data_dict, ensure_ascii=False)
    if existing:
        conn.execute(
            'UPDATE checkins SET data = ?, updated_at = ? WHERE date = ?',
            (json_data, now, date_str)
        )
    else:
        conn.execute(
            'INSERT INTO checkins (date, data, created_at, updated_at) VALUES (?, ?, ?, ?)',
            (date_str, json_data, now, now)
        )
    conn.commit()
    conn.close()


def delete_checkin(date_str):
    """删除某天的打卡记录"""
    conn = get_conn()
    conn.execute('DELETE FROM checkins WHERE date = ?', (date_str,))
    conn.commit()
    conn.close()


def get_all_checkins():
    """获取所有打卡记录，按日期倒序"""
    conn = get_conn()
    rows = conn.execute('SELECT * FROM checkins ORDER BY date DESC').fetchall()
    conn.close()
    results = []
    for row in rows:
        results.append({
            'id': row['id'],
            'date': row['date'],
            'data': json.loads(row['data']),
            'created_at': row['created_at'],
            'updated_at': row['updated_at']
        })
    return results


def get_weeks_list():
    """返回所有已有打卡记录的周号列表"""
    conn = get_conn()
    rows = conn.execute('SELECT DISTINCT date FROM checkins ORDER BY date').fetchall()
    conn.close()
    return [r['date'] for r in rows]


def get_daily_backup(week_str):
    """获取某周的原始日记录（从备份表）"""
    from datetime import datetime as _dt, timedelta
    if '-W' not in week_str:
        return []
    year_part, week_part = week_str.split('-W')
    try:
        year = int(year_part)
        week = int(week_part)
    except (ValueError, IndexError):
        return []
    jan1 = _dt(year, 1, 1)
    delta = timedelta(days=(week - 1) * 7 - jan1.weekday())
    monday = jan1 + delta
    dates = [monday.strftime('%Y-%m-%d')]
    for i in range(1, 7):
        dates.append((monday + timedelta(days=i)).strftime('%Y-%m-%d'))
    conn = get_conn()
    placeholders = ','.join('?' for _ in dates)
    exists = conn.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='checkins_daily_backup'").fetchone()
    if not exists:
        conn.close()
        return []
    rows = conn.execute(
        f"SELECT date, data FROM checkins_daily_backup WHERE date IN ({placeholders}) ORDER BY date",
        dates
    ).fetchall()
    conn.close()
    results = []
    for row in rows:
        results.append({'date': row['date'], 'data': json.loads(row['data'])})
    return results


def _aggregate_daily_to_weekly(conn):
    """将 checkins_daily_backup 的日数据聚合为周数据，写入 checkins"""
    from datetime import datetime as _dt
    rows = conn.execute('SELECT date, data FROM checkins_daily_backup ORDER BY date').fetchall()
    weekly = {}
    for row in rows:
        try:
            d = _dt.strptime(row['date'], '%Y-%m-%d')
        except ValueError:
            continue
        iso_year, iso_week, _ = d.isocalendar()
        week_key = f"{iso_year}-W{iso_week:02d}"
        if week_key not in weekly:
            weekly[week_key] = {'morning': [], 'evening': [], 'study': []}
        data = json.loads(row['data'])
        for mi in data.get('morning', []):
            text = mi if isinstance(mi, str) else mi.get('text', '')
            if text:
                existing_texts = {x if isinstance(x, str) else x.get('text', '') for x in weekly[week_key]['morning']}
                if text not in existing_texts:
                    weekly[week_key]['morning'].append(mi)
        for ei in data.get('evening', []):
            mst = ei.get('mistake', '') if isinstance(ei, dict) else ''
            if mst:
                existing = {x.get('mistake', '') if isinstance(x, dict) else x for x in weekly[week_key]['evening']}
                if mst not in existing:
                    weekly[week_key]['evening'].append(ei if isinstance(ei, dict) else {'mistake': ei, 'improvement': ''})
        existing_names = {}
        for si in weekly[week_key]['study']:
            nm = si.get('name', '') if isinstance(si, dict) else str(si)
            if nm:
                existing_names[nm] = si
        for si in data.get('study', []):
            nm = si.get('name', '') if isinstance(si, dict) else str(si)
            if nm and nm not in existing_names:
                weekly[week_key]['study'].append(si)
                existing_names[nm] = si
    now = _dt.now().isoformat()
    for week_key in sorted(weekly.keys()):
        conn.execute(
            'INSERT INTO checkins (date, data, created_at, updated_at) VALUES (?, ?, ?, ?)',
            (week_key, json.dumps(weekly[week_key], ensure_ascii=False), now, now)
        )