package models

import (
	"fmt"

	"gorm.io/gorm"
)

const requiredSchemaScript = "0001_baseline.up.sql"

var requiredSchema = struct {
	checksum string
	tables   []string
}{
	checksum: "ee621597df0d1c80e98cf38b941c1ac00e62f570223b9818bdab20c4e6f96689",
	tables:   []string{"files_object"},
}

// RequireSchemaVersion 确认当前数据库已经由受控迁移脚本初始化。
func RequireSchemaVersion(db *gorm.DB, service string) error {
	if db == nil {
		return fmt.Errorf("%s 数据库连接未初始化", service)
	}

	var count int64
	err := db.Raw(`
SELECT COUNT(*)
FROM public.ops_schema_migrations
WHERE service = ? AND script_name = ? AND checksum = ? AND status = 'success'`,
		service, requiredSchemaScript, requiredSchema.checksum).Scan(&count).Error
	if err != nil {
		return fmt.Errorf("%s 数据库版本检查失败，请先执行 migrate-all.sh up --service %s: %w", service, service, err)
	}
	if count != 1 {
		return fmt.Errorf("%s 数据库迁移版本不匹配，请执行 migrate-all.sh status --service %s", service, service)
	}

	for _, table := range requiredSchema.tables {
		var valid bool
		err = db.Raw(`
SELECT to_regclass(?) IS NOT NULL AND EXISTS (
  SELECT 1
  FROM pg_constraint c
  JOIN pg_class t ON t.oid = c.conrelid
  JOIN pg_namespace n ON n.oid = t.relnamespace
  WHERE n.nspname = 'public' AND t.relname = ? AND c.contype = 'p'
)`, "public."+table, table).Scan(&valid).Error
		if err != nil || !valid {
			return fmt.Errorf("%s 数据库关键表结构不完整：%s", service, table)
		}
	}
	return nil
}

func RequireStorageProvider(db *gorm.DB, provider string) error {
	var providers []string
	if err := db.Model(&FileObject{}).Distinct("provider").Pluck("provider", &providers).Error; err != nil {
		return fmt.Errorf("检查文件存储类型失败: %w", err)
	}
	for _, storedProvider := range providers {
		if storedProvider != provider {
			return fmt.Errorf("数据库存在 %s 存储的文件，当前配置为 %s，禁止混用存储后端", storedProvider, provider)
		}
	}
	return nil
}