package models

import (
	"fmt"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

var DBService *gorm.DB

// migrationAdvisoryLockKey scopes the PostgreSQL session lock to SenlinAI schema changes.
const migrationAdvisoryLockKey int64 = 0x53454e4c494e4149

func New(dsn string) error {
	// 启用 Gorm 跨驱动错误翻译，业务层无需解析 Postgres 错误文本或 SQLSTATE。
	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{TranslateError: true})
	if err != nil {
		return err
	}

	if err := AutoMigrate(db); err != nil {
		return err
	}

	DBService = db
	return nil
}

func AutoMigrate(database *gorm.DB) error {
	if !migrationAdvisoryLockRequired(database.Dialector.Name()) {
		return autoMigrateUnlocked(database)
	}
	// Connection pins every migration statement to one PostgreSQL session so the
	// advisory lock covers both Gorm's schema work and the versioned data repairs.
	return database.Connection(func(connection *gorm.DB) (resultErr error) {
		if err := connection.Exec("SELECT pg_advisory_lock(?)", migrationAdvisoryLockKey).Error; err != nil {
			return fmt.Errorf("acquire schema migration advisory lock: %w", err)
		}
		defer func() {
			if err := connection.Exec("SELECT pg_advisory_unlock(?)", migrationAdvisoryLockKey).Error; resultErr == nil && err != nil {
				resultErr = fmt.Errorf("release schema migration advisory lock: %w", err)
			}
		}()
		return autoMigrateUnlocked(connection)
	})
}

func migrationAdvisoryLockRequired(dialect string) bool {
	return dialect == "postgres"
}

func autoMigrateUnlocked(database *gorm.DB) error {
	if err := database.AutoMigrate(
		&SenlinAgentSchemaMigration{},
		&SenlinAgentUser{},
		&SenlinAgentProject{},
		&SenlinAgentInboxItem{},
		&SenlinAgentInboxSuggestion{},
		&SenlinAgentTask{},
		&SenlinAgentNote{},
		&SenlinAgentSource{},
		&SenlinAgentAISession{},
		&SenlinAgentTag{},
		&SenlinAgentProjectChannel{},
		&SenlinAgentCronPlan{},
		&SenlinAgentProjectEvent{},
		&SenlinAgentAIKey{},
		&SenlinAgentAICallLog{},
		&SenlinAgentAIRateBucket{},
		&SenlinAgentTaskShare{},
	); err != nil {
		return err
	}
	return runVersionedMigrations(database)
}