package schema

import (
	"fmt"
	"strings"
	"sync"

	"git.fsdpf.net/go/db/v2"
)

type Schema interface {
	// 判断表是否存在
	TableExists(table string) (bool, error)
	// 字段列
	GetColumnListing(table string) ([]string, error)
	// 创建表
	CompileCreate(bp *Blueprint) []string
	// 添加字段
	CompileAdd(bp *Blueprint) []string
	// 修改字段
	CompileChange(bp *Blueprint) []string
	// 删除表
	CompileDrop(bp *Blueprint) []string
	// 删除表, 先判断再删除
	CompileDropIfExists(bp *Blueprint) []string
	// 删除表, 删除列
	CompileDropColumn(bp *Blueprint) []string
	// 表重命名
	CompileRename(bp *Blueprint) []string
	// 生成SQL
	GenerateSQL(sql string, args ...any) string
}

var (
	dialects   = make(map[string]func(db *db.Database) Schema)
	dialectsMu sync.RWMutex
)

func RegisterDialect(name string, sc func(db *db.Database) Schema) {
	dialectsMu.Lock()
	defer dialectsMu.Unlock()
	lowerName := strings.ToLower(name)
	dialects[lowerName] = sc
}

func DeregisterDialect(name string) {
	dialectsMu.Lock()
	defer dialectsMu.Unlock()
	delete(dialects, strings.ToLower(name))
}

func GetSchemaDialect(db *db.Database) Schema {
	name := strings.ToLower(db.Dialect())
	if d, ok := dialects[name]; ok {
		return d(db)
	}

	panic(fmt.Sprintf("Unsupported driver: %s", name))
}