// Package sql2go...
//
// Description : sql2go...
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 2021-10-25 4:49 下午
package sql2go

import (
	"errors"
	"strings"

	"git.zhangdeman.cn/zhangdeman/util"

	"github.com/xwb1989/sqlparser"
)

const (
	// CreateSQLColumnTPL 每个字段的模版
	CreateSQLColumnTPL = "    {FIELD} {TYPE} `json:\"{JSON_TAG}\" gorm:\"column:{COLUMN};default:{DEFAULT_VALUE};{NOT_NULL}\"` // {COMMENT}"
)

// BasicTableInfo ...
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 11:47 上午 2021/11/17
type BasicTableInfo struct {
	TableName        string
	ModelStruct      string
	PrimaryField     string
	PrimaryFieldType string
}

// ParseCreateTableSql 解析建表sql
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 4:49 下午 2021/10/25
func ParseCreateTableSql(sql string, withGetTableFunc bool) (string, *BasicTableInfo, error) {
	var (
		stmt  sqlparser.Statement
		err   error
		basic *BasicTableInfo
	)
	basic = &BasicTableInfo{
		TableName:        "",
		ModelStruct:      "",
		PrimaryField:     "ID",
		PrimaryFieldType: "",
	}
	sql = strings.ReplaceAll(strings.ReplaceAll(sql, "CURRENT_TIMESTAMP()", "CURRENT_TIMESTAMP"), "current_timestamp()", "CURRENT_TIMESTAMP")
	if stmt, err = sqlparser.ParseStrictDDL(sql); nil != err {
		return "", nil, err
	}

	r, ok := stmt.(*sqlparser.DDL)
	if !ok {
		return "", nil, errors.New("input sql is not ddl")
	}
	basic.TableName = sqlparser.String(r.NewName)
	basic.ModelStruct = util.String.SnakeCaseToCamel(basic.TableName)
	structResult := "type " + basic.ModelStruct + " struct { \n"

	for _, item := range r.TableSpec.Columns {
		comment := ""
		if item.Type.Comment == nil {
			comment = item.Name.String()
		} else {
			comment = string(item.Type.Comment.Val)
		}
		data := map[string]string{
			"{FIELD}":         util.String.SnakeCaseToCamel(item.Name.String()),
			"{COLUMN}":        item.Name.String(),
			"{JSON_TAG}":      item.Name.String(),
			"{DEFAULT_VALUE}": "",
			"{COMMENT}":       comment,
			"{TYPE}":          sqlTypeMap[item.Type.Type],
		}
		if data["{FIELD}"] == "ID" {
			basic.PrimaryFieldType = data["{TYPE}"]
		}
		if item.Type.NotNull {
			data["{NOT_NULL}"] = "NOT NULL"
		}
		if nil != item.Type.Default {
			data["{DEFAULT_VALUE}"] += string(item.Type.Default.Val)
		}
		val := CreateSQLColumnTPL
		for k, v := range data {
			val = strings.ReplaceAll(val, k, v)
		}
		structResult += val + "\n"
	}
	structResult = structResult + "}"
	if withGetTableFunc {
		// 生成表名称获取方法
		tableFirst := string([]byte(basic.TableName)[:1])
		funcTpl := `

// TableName 获取表名称
func ({{TABLE_FIRST}} {{TABLE_STRUCT_NAME}}) TableName() string {
	return "{{TABLE_NAME}}"
}`
		replaceTable := map[string]string{
			"{{TABLE_FIRST}}":       tableFirst,
			"{{TABLE_STRUCT_NAME}}": basic.ModelStruct,
			"{{TABLE_NAME}}":        basic.TableName,
		}
		for k, v := range replaceTable {
			funcTpl = strings.ReplaceAll(funcTpl, k, v)
		}
		structResult = structResult + funcTpl
	}

	return structResult, basic, nil
}