#ifndef HUMANUS_MEMORY_MEM0_STORAGE_H
#define HUMANUS_MEMORY_MEM0_STORAGE_H

#include <sqlite3.h>

namespace humanus {

namespace mem0 {

struct SQLiteManager {
    std::shared_ptr<sqlite3> db;
    std::mutex mutex;

    SQLiteManager(const std::string& db_path) {
        int rc = sqlite3_open(db_path.c_str(), &db);
        if (rc) {
            throw std::runtime_error("Failed to open database: " + std::string(sqlite3_errmsg(db)));
        }
        _migrate_history_table();
        _create_history_table()
    }

    void _migrate_history_table() {
        std::lock_guard<std::mutex> lock(mutex);
        
        char* errmsg = nullptr;
        sqlite3_stmt* stmt = nullptr;
        
        // 检查历史表是否存在
        int rc = sqlite3_prepare_v2(db.get(), "SELECT name FROM sqlite_master WHERE type='table' AND name='history'", -1, &stmt, nullptr);
        if (rc != SQLITE_OK) {
            throw std::runtime_error("Failed to prepare statement: " + std::string(sqlite3_errmsg(db.get())));
        }
        
        bool table_exists = false;
        if (sqlite3_step(stmt) == SQLITE_ROW) {
            table_exists = true;
        }
        sqlite3_finalize(stmt);
        
        if (table_exists) {
            // 获取当前表结构
            std::map<std::string, std::string> current_schema;
            rc = sqlite3_prepare_v2(db.get(), "PRAGMA table_info(history)", -1, &stmt, nullptr);
            if (rc != SQLITE_OK) {
                throw std::runtime_error("Failed to prepare statement: " + std::string(sqlite3_errmsg(db.get())));
            }
            
            while (sqlite3_step(stmt) == SQLITE_ROW) {
                std::string column_name = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 1));
                std::string column_type = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 2));
                current_schema[column_name] = column_type;
            }
            sqlite3_finalize(stmt);
            
            // 定义预期表结构
            std::map<std::string, std::string> expected_schema = {
                {"id", "TEXT"},
                {"memory_id", "TEXT"},
                {"old_memory", "TEXT"},
                {"new_memory", "TEXT"},
                {"new_value", "TEXT"},
                {"event", "TEXT"},
                {"created_at", "DATETIME"},
                {"updated_at", "DATETIME"},
                {"is_deleted", "INTEGER"}
            };
            
            // 检查表结构是否一致
            if (current_schema != expected_schema) {
                // 重命名旧表
                rc = sqlite3_exec(db.get(), "ALTER TABLE history RENAME TO old_history", nullptr, nullptr, &errmsg);
                if (rc != SQLITE_OK) {
                    std::string error = errmsg ? errmsg : "Unknown error";
                    sqlite3_free(errmsg);
                    throw std::runtime_error("Failed to rename table: " + error);
                }
                
                // 创建新表
                rc = sqlite3_exec(db.get(), 
                    "CREATE TABLE IF NOT EXISTS history ("
                    "id TEXT PRIMARY KEY,"
                    "memory_id TEXT,"
                    "old_memory TEXT,"
                    "new_memory TEXT,"
                    "new_value TEXT,"
                    "event TEXT,"
                    "created_at DATETIME,"
                    "updated_at DATETIME,"
                    "is_deleted INTEGER"
                    ")", nullptr, nullptr, &errmsg);
                if (rc != SQLITE_OK) {
                    std::string error = errmsg ? errmsg : "Unknown error";
                    sqlite3_free(errmsg);
                    throw std::runtime_error("Failed to create table: " + error);
                }
                
                // 复制数据
                rc = sqlite3_exec(db.get(), 
                    "INSERT INTO history (id, memory_id, old_memory, new_memory, new_value, event, created_at, updated_at, is_deleted) "
                    "SELECT id, memory_id, prev_value, new_value, new_value, event, timestamp, timestamp, is_deleted "
                    "FROM old_history", nullptr, nullptr, &errmsg);
                if (rc != SQLITE_OK) {
                    std::string error = errmsg ? errmsg : "Unknown error";
                    sqlite3_free(errmsg);
                    throw std::runtime_error("Failed to copy data: " + error);
                }
                
                // 删除旧表
                rc = sqlite3_exec(db.get(), "DROP TABLE old_history", nullptr, nullptr, &errmsg);
                if (rc != SQLITE_OK) {
                    std::string error = errmsg ? errmsg : "Unknown error";
                    sqlite3_free(errmsg);
                    throw std::runtime_error("Failed to drop old table: " + error);
                }
            }
        }
    }

    void _create_history_table() {
        std::lock_guard<std::mutex> lock(mutex);
        
        char* errmsg = nullptr;
        int rc = sqlite3_exec(db.get(), 
            "CREATE TABLE IF NOT EXISTS history ("
            "id TEXT PRIMARY KEY,"
            "memory_id TEXT,"
            "old_memory TEXT,"
            "new_memory TEXT,"
            "new_value TEXT,"
            "event TEXT,"
            "created_at DATETIME,"
            "updated_at DATETIME,"
            "is_deleted INTEGER"
            ")", nullptr, nullptr, &errmsg);
        
        if (rc != SQLITE_OK) {
            std::string error = errmsg ? errmsg : "Unknown error";
            sqlite3_free(errmsg);
            throw std::runtime_error("Failed to create history table: " + error);
        }
    }
};

} // namespace mem0

} // namespace humanus

#endif // HUMANUS_MEMORY_MEM0_STORAGE_H