package sql

import (
	"errors"
	"git.sxidc.com/go-tools/utils/strutils"
	"github.com/iancoleman/strcase"
	"reflect"
	"strings"
	"time"
)

const (
	sqlMappingDefaultKeyColumnName     = "id"
	sqlMappingDefaultJoinWith          = "::"
	sqlMappingTagPartSeparator         = ";"
	sqlMappingTagPartKeyValueSeparator = ":"
)

const (
	sqlMappingTagKey      = "sqlmapping"
	sqlMappingIgnore      = "-"
	sqlMappingColumn      = "column"
	sqlMappingKey         = "key"
	sqlMappingNotUpdate   = "notUpdate"
	sqlMappingUpdateClear = "updateClear"
	sqlMappingAes         = "aes"
	sqlMappingJoinWith    = "joinWith"
)

type Mapping struct {
	MappingElement map[string]any
}

type MappingColumn struct {
	Name           string
	IsKey          bool
	CanUpdate      bool
	CanUpdateClear bool
	AESKey         string
	JoinWith       string

	// 原字段的反射结构
	OriginFieldType  reflect.Type
	OriginFieldValue reflect.Value

	// 值类型的反射结构
	FieldTypeElem  reflect.Type
	FieldValueElem reflect.Value
}

func ParseSqlMappingTag(e any) (*Mapping, error) {
	if e == nil {
		return nil, errors.New("没有传递实体")
	}

	entityType := reflect.TypeOf(e)
	if entityType.Kind() == reflect.Ptr {
		entityType = entityType.Elem()
	}

	if entityType.Kind() != reflect.Struct {
		return nil, errors.New("传递的实体不是结构类型")
	}

	entityValue := reflect.ValueOf(e)
	if entityValue.Kind() == reflect.Ptr {
		entityValue = entityValue.Elem()
	}

	sqlMapping := new(Mapping)
	sqlMapping.MappingElement = make(map[string]any)

	fieldNum := entityType.NumField()
	for i := 0; i < fieldNum; i++ {
		field := entityType.Field(i)
		fieldValue := entityValue.Field(i)

		element, err := parseSqlMappingElement(field, fieldValue)
		if err != nil {
			return nil, err
		}

		if element == nil {
			continue
		}

		sqlMapping.MappingElement[field.Name] = element
	}

	return sqlMapping, nil
}

func parseSqlMappingElement(field reflect.StructField, fieldValue reflect.Value) (any, error) {
	sqlMappingTag := field.Tag.Get(sqlMappingTagKey)
	if sqlMappingTag == sqlMappingIgnore {
		return nil, nil
	}

	fieldValueTypeElem := field.Type
	if field.Type.Kind() == reflect.Ptr {
		fieldValueTypeElem = field.Type.Elem()
	}

	fieldValueElem := fieldValue
	if fieldValue.Kind() == reflect.Ptr {
		if !fieldValue.IsValid() || fieldValue.IsNil() {
			fieldValueElem = reflect.New(fieldValueTypeElem).Elem()
		} else {
			fieldValueElem = fieldValue.Elem()
		}
	}

	if fieldValueTypeElem.Kind() == reflect.Struct && fieldValueTypeElem != reflect.TypeOf(time.Time{}) {
		return ParseSqlMappingTag(fieldValueElem.Interface())
	}

	sqlColumn := &MappingColumn{
		Name:           strcase.ToSnake(field.Name),
		IsKey:          false,
		CanUpdate:      true,
		CanUpdateClear: false,
		AESKey:         "",
		JoinWith:       sqlMappingDefaultJoinWith,

		OriginFieldType:  field.Type,
		OriginFieldValue: fieldValue,
		FieldTypeElem:    fieldValueTypeElem,
		FieldValueElem:   fieldValueElem,
	}

	if sqlColumn.Name == sqlMappingDefaultKeyColumnName {
		sqlColumn.IsKey = true
		sqlColumn.CanUpdate = false
	}

	if strutils.IsStringEmpty(sqlMappingTag) {
		return sqlColumn, nil
	}

	sqlMappingParts := strings.Split(sqlMappingTag, sqlMappingTagPartSeparator)
	if sqlMappingParts != nil || len(sqlMappingParts) != 0 {
		for _, sqlMappingPart := range sqlMappingParts {
			sqlPartKeyValue := strings.SplitN(strings.TrimSpace(sqlMappingPart), sqlMappingTagPartKeyValueSeparator, 2)
			if sqlPartKeyValue != nil && len(sqlPartKeyValue) == 2 && strutils.IsStringNotEmpty(sqlPartKeyValue[1]) {
				sqlPartKeyValue[1] = strings.Trim(sqlPartKeyValue[1], "'")
			}

			switch sqlPartKeyValue[0] {
			case sqlMappingColumn:
				if strutils.IsStringEmpty(sqlPartKeyValue[1]) {
					return nil, errors.New("column没有赋值列名")
				}

				sqlColumn.Name = sqlPartKeyValue[1]
			case sqlMappingKey:
				sqlColumn.IsKey = true
				sqlColumn.CanUpdate = false
			case sqlMappingNotUpdate:
				sqlColumn.CanUpdate = false
				sqlColumn.CanUpdateClear = false
			case sqlMappingUpdateClear:
				if !sqlColumn.CanUpdate {
					sqlColumn.CanUpdateClear = false
				} else {
					sqlColumn.CanUpdateClear = true
				}
			case sqlMappingAes:
				if len(sqlPartKeyValue[1]) != 32 {
					return nil, errors.New("AES密钥长度应该为32个字节")
				}

				sqlColumn.AESKey = sqlPartKeyValue[1]
			case sqlMappingJoinWith:
				if strutils.IsStringEmpty(sqlPartKeyValue[1]) {
					return nil, errors.New(sqlMappingJoinWith + "没有赋值分隔符")
				}

				if fieldValueTypeElem.Kind() != reflect.Slice || fieldValueTypeElem.Elem().Kind() != reflect.String {
					return nil, errors.New(sqlMappingJoinWith + "应该添加在[]string字段上")
				}

				sqlColumn.JoinWith = sqlPartKeyValue[1]
			default:
				continue
			}
		}
	}

	return sqlColumn, nil
}