"""
OCR数据库迁移脚本
运行: python -m scripts.migrate_ocr
"""
import os
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).parent.parent))

from dotenv import load_dotenv
load_dotenv()

import psycopg2
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT


def get_db_connection():
    """获取数据库连接"""
    return psycopg2.connect(
        host=os.getenv('DB_HOST', 'localhost'),
        port=os.getenv('DB_PORT', '5432'),
        user=os.getenv('DB_USER', 'postgres'),
        password=os.getenv('DB_PASSWORD', ''),
        database=os.getenv('DB_NAME', 'model_square')
    )


def table_exists(cursor):
    """检查表是否存在"""
    cursor.execute("""
        SELECT EXISTS (
            SELECT FROM information_schema.tables 
            WHERE table_schema = 'aigcspace' 
            AND table_name = 'ocr_tasks'
        );
    """)
    return cursor.fetchone()[0]


def migrate():
    """执行迁移"""
    conn = get_db_connection()
    conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
    cursor = conn.cursor()
    
    try:
        if table_exists(cursor):
            print("✓ 表 aigcspace.ocr_tasks 已存在")
            return
        
        print("开始创建 OCR 任务表...")
        
        # 创建表
        cursor.execute("""
            CREATE TABLE aigcspace.ocr_tasks (
                id SERIAL PRIMARY KEY,
                task_id VARCHAR(64) UNIQUE NOT NULL,
                user_id VARCHAR(50) NOT NULL REFERENCES aigcspace.users(id) ON DELETE CASCADE,
                task_type VARCHAR(50) NOT NULL,
                custom_prompt TEXT,
                status VARCHAR(20) NOT NULL DEFAULT 'pending',
                progress INTEGER DEFAULT 0 CHECK (progress >= 0 AND progress <= 100),
                total_images INTEGER NOT NULL CHECK (total_images > 0 AND total_images <= 10),
                processed_images INTEGER DEFAULT 0 CHECK (processed_images >= 0),
                results JSONB DEFAULT '{}'::jsonb,
                error_message TEXT,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                completed_at TIMESTAMP,
                
                CONSTRAINT check_processed_images CHECK (processed_images <= total_images),
                CONSTRAINT check_status CHECK (status IN ('pending', 'processing', 'completed', 'failed', 'cancelled'))
            );
        """)
        print("✓ 表创建成功")
        
        # 创建索引
        indexes = [
            "CREATE INDEX idx_ocr_tasks_task_id ON aigcspace.ocr_tasks(task_id);",
            "CREATE INDEX idx_ocr_tasks_user_id ON aigcspace.ocr_tasks(user_id);",
            "CREATE INDEX idx_ocr_tasks_status ON aigcspace.ocr_tasks(status);",
            "CREATE INDEX idx_ocr_tasks_user_status ON aigcspace.ocr_tasks(user_id, status);",
            "CREATE INDEX idx_ocr_tasks_created_at ON aigcspace.ocr_tasks(created_at DESC);"
        ]
        for idx_sql in indexes:
            cursor.execute(idx_sql)
        print("✓ 索引创建成功")
        
        # 创建触发器
        cursor.execute("""
            CREATE OR REPLACE FUNCTION update_ocr_tasks_updated_at()
            RETURNS TRIGGER AS $$
            BEGIN
                NEW.updated_at = CURRENT_TIMESTAMP;
                RETURN NEW;
            END;
            $$ LANGUAGE plpgsql;
            
            CREATE TRIGGER trigger_update_ocr_tasks_updated_at
                BEFORE UPDATE ON aigcspace.ocr_tasks
                FOR EACH ROW
                EXECUTE FUNCTION update_ocr_tasks_updated_at();
        """)
        print("✓ 触发器创建成功")
        
        # 添加注释
        comments = [
            "COMMENT ON TABLE aigcspace.ocr_tasks IS 'OCR识别任务表，同时作为历史记录表';",
            "COMMENT ON COLUMN aigcspace.ocr_tasks.task_id IS '任务唯一标识符（UUID）';",
            "COMMENT ON COLUMN aigcspace.ocr_tasks.status IS '任务状态：pending/processing/completed/failed/cancelled';",
            "COMMENT ON COLUMN aigcspace.ocr_tasks.results IS 'JSONB格式存储：{images: [], thumbnails: [], texts: []}';"
        ]
        for comment_sql in comments:
            cursor.execute(comment_sql)
        print("✓ 注释添加成功")
        
        print("\n✅ OCR数据库迁移完成！")
        
    except Exception as e:
        print(f"❌ 迁移失败: {e}")
        raise
    finally:
        cursor.close()
        conn.close()


def rollback():
    """回滚迁移"""
    conn = get_db_connection()
    conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
    cursor = conn.cursor()
    
    try:
        if not table_exists(cursor):
            print("✓ 表 aigcspace.ocr_tasks 不存在，无需回滚")
            return
        
        print("开始回滚 OCR 数据库迁移...")
        
        cursor.execute("DROP TRIGGER IF EXISTS trigger_update_ocr_tasks_updated_at ON aigcspace.ocr_tasks;")
        cursor.execute("DROP FUNCTION IF EXISTS update_ocr_tasks_updated_at();")
        cursor.execute("DROP TABLE IF EXISTS aigcspace.ocr_tasks CASCADE;")
        
        print("✅ OCR数据库迁移回滚完成！")
        
    except Exception as e:
        print(f"❌ 回滚失败: {e}")
        raise
    finally:
        cursor.close()
        conn.close()


def status():
    """查看迁移状态"""
    conn = get_db_connection()
    conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
    cursor = conn.cursor()
    
    try:
        exists = table_exists(cursor)
        print(f"表 aigcspace.ocr_tasks: {'✓ 已创建' if exists else '✗ 未创建'}")
        
        if exists:
            cursor.execute("SELECT COUNT(*) FROM aigcspace.ocr_tasks;")
            count = cursor.fetchone()[0]
            print(f"记录数: {count}")
            
            cursor.execute("""
                SELECT indexname FROM pg_indexes 
                WHERE schemaname = 'aigcspace' AND tablename = 'ocr_tasks';
            """)
            indexes = [row[0] for row in cursor.fetchall()]
            print(f"索引数: {len(indexes)}")
            
    except Exception as e:
        print(f"❌ 查看状态失败: {e}")
        raise
    finally:
        cursor.close()
        conn.close()


if __name__ == "__main__":
    import argparse
    
    parser = argparse.ArgumentParser(description='OCR数据库迁移脚本')
    parser.add_argument('--action', choices=['migrate', 'rollback', 'status'], 
                       default='migrate', help='操作类型')
    args = parser.parse_args()
    
    if args.action == 'migrate':
        migrate()
    elif args.action == 'rollback':
        rollback()
    elif args.action == 'status':
        status()