#!/usr/bin/env python3
"""流失用户最后一次完课的课程分布（按 Unit 汇总）
口径：对 L1/L2 流失用户（最后完课距今>30天），统计最后一次完课所在 Unit
"""
import os
import psycopg2

PG_HOST = "bj-postgres-16pob4sg.sql.tencentcdb.com"
PG_PORT = 28591
PG_USER = "ai_member"
PG_DB = "vala_bi"
PG_PASSWORD = os.environ.get("PG_ONLINE_PASSWORD", "")

conn = psycopg2.connect(
    host=PG_HOST, port=PG_PORT, user=PG_USER,
    password=PG_PASSWORD, dbname=PG_DB
)
cur = conn.cursor()

level_ranges = {"L1": (333, 581), "L2": (55, 331)}
shards = list(range(8))

for level, (ch_min, ch_max) in level_ranges.items():
    union_parts = []
    for s in shards:
        union_parts.append(f"""
            SELECT c.account_id, r.chapter_id, r.created_at
            FROM bi_user_chapter_play_record_{s} r
            JOIN bi_vala_app_character c ON r.user_id = c.id
            WHERE r.play_status = 1
              AND r.chapter_id BETWEEN {ch_min} AND {ch_max}
        """)
    
    union_sql = " UNION ALL ".join(union_parts)
    
    # Get last study per user, and the chapter_id of that last study
    sql = f"""
        WITH all_records AS (
            {union_sql}
        ),
        user_last AS (
            SELECT DISTINCT ON (account_id) 
                account_id, chapter_id, created_at as last_study
            FROM all_records
            ORDER BY account_id, created_at DESC
        ),
        churned AS (
            SELECT account_id, chapter_id
            FROM user_last
            WHERE last_study < NOW() - INTERVAL '30 days'
        )
        SELECT 
            l.course_unit,
            COUNT(*) as cnt,
            ROUND(100.0 * COUNT(*) / SUM(COUNT(*)) OVER(), 1) as pct
        FROM churned c
        JOIN bi_level_unit_lesson l ON c.chapter_id = l.id
        GROUP BY l.course_unit
        ORDER BY l.course_unit
    """
    
    cur.execute(sql)
    rows = cur.fetchall()
    print(f"\n=== {level} 流失用户最后完课 Unit 分布 ===")
    total = 0
    for unit, cnt, pct in rows:
        print(f"  {unit}: {cnt}人 ({pct}%)")
        total += cnt
    print(f"  合计: {total}人")

cur.close()
conn.close()