package plugins

import (
	"context"
	"encoding/json"
	"fmt"
	"reflect"
	"regexp"
	"strconv"
	"strings"

	"git.nspix.com/golang/micro/helper/utils"
	"git.nspix.com/golang/rest/v2"
	errors2 "git.nspix.com/golang/rest/v2/errors"
	"github.com/go-playground/validator/v10"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	"gorm.io/gorm/schema"
)

const (
	SkipValidations = "validations:skip_validations"
)

type (
	validateScope struct{}

	validScope struct {
		Db     *gorm.DB
		Column string
		Model  interface{}
	}

	validation struct {
		curd *rest.CRUD
	}
)

var (
	validate         = validator.New()
	validateScopeKey = validateScope{}

	telephoneRegex = regexp.MustCompile("^\\d{5,20}$")
)

func init() {

	_ = validate.RegisterValidationCtx("telephone", func(ctx context.Context, fl validator.FieldLevel) bool {
		val := fmt.Sprint(fl.Field().Interface())
		return telephoneRegex.MatchString(val)
	})

	_ = validate.RegisterValidationCtx("db_unique", func(ctx context.Context, fl validator.FieldLevel) bool {
		val := fl.Field().Interface()
		var (
			sp       *validScope
			ok       bool
			count    int64
			err      error
			sess     *gorm.DB
			field    *schema.Field
			refValue reflect.Value
		)
		if sp, ok = ctx.Value(validateScopeKey).(*validScope); !ok {
			return true
		}
		sess = sp.Db.Scopes(func(db *gorm.DB) *gorm.DB {
			s := db.Session(&gorm.Session{})
			s.Statement = &gorm.Statement{
				DB:       db,
				ConnPool: db.Statement.ConnPool,
				Context:  db.Statement.Context,
				Clauses:  map[string]clause.Clause{},
			}
			return s
		})
		if err = sess.Statement.Parse(sp.Model); err == nil {
			if len(sess.Statement.Schema.PrimaryFields) > 0 {
				field = sess.Statement.Schema.PrimaryFields[0]
				refValue = reflect.Indirect(reflect.ValueOf(sp.Model))
				for _, n := range field.BindNames {
					refValue = refValue.FieldByName(n)
				}
			}
		}
		if refValue.IsValid() && !refValue.IsZero() && field != nil {
			sess.Model(sp.Model).Where(sp.Column+"=? AND "+field.Name+" != ?", val, refValue.Interface()).Count(&count)
		} else {
			sess.Model(sp.Model).Where(sp.Column+"=?", val).Count(&count)
		}
		if count > 0 {
			return false
		}
		return true
	})
}

func generateTag(scm *rest.Schema, scenario string, rule rest.Rule) string {
	var s string
	if rule.Min != 0 {
		s += ",min=" + strconv.Itoa(rule.Min)
	}
	if rule.Max != 0 {
		s += ",max=" + strconv.Itoa(rule.Max)
	}
	//主键不做判断
	if rule.Unique && scm.PrimaryKey == 0 {
		s += ",db_unique"
	}
	if rule.Type != "" {
		s += "," + rule.Type
	}
	if rule.Required != nil && len(rule.Required) > 0 {
		for _, v := range rule.Required {
			if v == scenario {
				s += ",required"
			}
		}
	}
	if s != "" {
		return s[1:]
	} else {
		return s
	}
}

func formatError(rule rest.Rule, scm *rest.Schema, tag string) string {
	var s string
	switch tag {
	case "db_unique":
		s = scm.Label + "值已经存在."
		break
	case "required":
		s = scm.Label + "值不能为空."
	case "max":
		if scm.Type == "string" {
			s = scm.Label + "长度不能大于" + strconv.Itoa(rule.Max)
		} else {
			s = scm.Label + "值不能大于" + strconv.Itoa(rule.Max)
		}
	case "min":
		if scm.Type == "string" {
			s = scm.Label + "长度不能小于" + strconv.Itoa(rule.Max)
		} else {
			s = scm.Label + "值不能小于" + strconv.Itoa(rule.Max)
		}
	}
	return s
}

func (vv *validation) validation(db *gorm.DB) {
	if result, ok := db.Get(SkipValidations); ok && result.(bool) {
		return
	}
	var (
		ok           bool
		err          error
		ruleString   string
		stmt         *gorm.Statement
		model        rest.Model
		rule         rest.Rule
		scenario     string
		skipValidate bool
		value        reflect.Value
		schemas      []*rest.Schema
	)
	stmt = db.Statement
	if stmt.Model == nil {
		return
	}
	if model, ok = stmt.Model.(rest.Model); !ok {
		return
	}
	scenario = rest.ScenarioUpdate
	for _, pk := range stmt.Schema.PrimaryFields {
		if utils.IsEmpty(stmt.ReflectValue.FieldByName(pk.Name).Interface()) {
			scenario = rest.ScenarioCreate
			break
		}
	}
	schemas = vv.curd.Schemas(stmt.ReflectValue.FieldByName("Namespace").String(), model.ModuleName(), model.TableName(), scenario)
	for _, scm := range schemas {
		if scm.Rules == "" {
			continue
		}
		if err = json.Unmarshal([]byte(scm.Rules), &rule); err != nil {
			continue
		}
		if ruleString = generateTag(scm, scenario, rule); ruleString == "" {
			continue
		}
		value = stmt.ReflectValue.FieldByName(stmt.Schema.LookUpField(scm.Column).Name)
		if !value.IsValid() {
			continue
		}
		skipValidate = false
		if strings.Contains(ruleString, "required") {
			//如果数值为整形,小数,Bool跳过验证
			if value.Interface() != nil {
				vType := reflect.ValueOf(value.Interface())
				switch vType.Kind() {
				case reflect.Bool:
					skipValidate = true
				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
					skipValidate = true
				case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
					skipValidate = true
				case reflect.Float32, reflect.Float64:
					skipValidate = true
				}
			}
			if skipValidate {
				continue
			}
		} else {
			if utils.IsEmpty(value.Interface()) {
				continue
			}
		}
		ctx := context.WithValue(context.Background(), validateScopeKey, &validScope{
			Db:     db,
			Column: scm.Column,
			Model:  stmt.Model,
		})
		if err = validate.VarCtx(ctx, value.Interface(), ruleString); err != nil {
			if errors, ok := err.(validator.ValidationErrors); ok {
				for _, e := range errors {
					_ = db.AddError(&errors2.StructError{
						Tag:     e.Tag(),
						Column:  scm.Column,
						Message: formatError(rule, scm, e.Tag()),
					})
				}
			} else {
				_ = db.AddError(err)
			}
			break
		}
	}
}

func RegisterValidationCallback(curd *rest.CRUD) {
	callback := curd.DB().Callback()
	vv := &validation{curd: curd}
	if callback.Create().Get("validations:validate") == nil {
		_ = callback.Create().Before("gorm:before_create").Register("validations:validate", vv.validation)
	}
	if callback.Update().Get("validations:validate") == nil {
		_ = callback.Update().Before("gorm:before_update").Register("validations:validate", vv.validation)
	}
}