package schema

import (
	"context"
	"encoding/json"
	"git.nspix.com/golang/micro/gateway/http"
	"git.nspix.com/golang/rest/internal/array"
	"git.nspix.com/golang/rest/scenario"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	"gorm.io/gorm/schema"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"time"
)

var (
	timeKind    = reflect.TypeOf(time.Time{}).Kind()
	timePtrKind = reflect.TypeOf(&time.Time{}).Kind()

	cached      map[string][]*Schema
	cacheLocker sync.RWMutex
)

func init() {
	cached = make(map[string][]*Schema)
}

type (
	Rule struct {
		Min      int      `json:"min"`
		Max      int      `json:"max"`
		Type     string   `json:"type"`
		Unique   bool     `json:"unique"`
		Required []string `json:"required"`
		Regular  string   `json:"regular"`
	}

	enumItem struct {
		Key interface{} `json:"key"`
		Val interface{} `json:"val"`
	}

	Options struct {
		Readonly    []string   `json:"readonly"`
		Disable     []string   `json:"disable"`
		Visible     []string   `json:"visible"`
		Items       []enumItem `json:"items"`
		Description string     `json:"description"`
	}

	Schema struct {
		Id       uint64 `json:"id" gorm:"primary_key"`
		Module   string `json:"module" gorm:"column:module_name;type:varchar(60)"`
		Table    string `json:"table" gorm:"column:table_name;type:varchar(120)"`
		Enable   bool   `json:"enable"`
		Column   string `json:"field" gorm:"type:varchar(120)"`
		Label    string `json:"label" gorm:"type:varchar(120)"`
		Type     string `json:"type" gorm:"type:varchar(120)"`
		Format   string `json:"format" gorm:"type:varchar(120)"`
		Scenario string `json:"visible" gorm:"type:varchar(120)"`
		Rules    string `json:"rules" gorm:"type:varchar(2048)"`
		Options  string `json:"options" gorm:"type:varchar(4096)"`
		Position int    `json:"position"`
		options  *Options
	}

	Field struct {
		Column   string `json:"column" gorm:"type:varchar(120)"`
		Label    string `json:"label" gorm:"type:varchar(120)"`
		Type     string `json:"type" gorm:"type:varchar(120)"`
		Format   string `json:"format" gorm:"type:varchar(120)"`
		Scenario string `json:"scenario" gorm:"type:varchar(120)"`
		Rules    string `json:"rules" gorm:"type:varchar(2048)"`
		Options  string `json:"options" gorm:"type:varchar(4096)"`
	}
)

func (r *Rule) String() string {
	buf, _ := json.Marshal(r)
	return string(buf)
}

func (sc *Schema) GetOptions() *Options {
	if sc.options == nil {
		sc.options = &Options{}
		_ = json.Unmarshal([]byte(sc.Options), sc.options)
	}
	return sc.options
}

func (sc Schema) TableName() string {
	return "schemas"
}

func newStatement(db *gorm.DB) *gorm.Statement {
	return &gorm.Statement{
		DB:       db,
		ConnPool: db.Statement.ConnPool,
		Context:  db.Statement.Context,
		Clauses:  map[string]clause.Clause{},
	}
}

func names(s string) string {
	var sb strings.Builder
	ss := strings.Split(s, "_")
	if len(ss) <= 0 {
		return ""
	}
	sb.WriteString(strings.Title(ss[0]))
	for _, i := range ss[1:] {
		sb.WriteString(" ")
		sb.WriteString(strings.Title(i))
	}
	return sb.String()
}

func IsNewRecord(value reflect.Value, stmt *gorm.Statement) bool {
	for _, pf := range stmt.Schema.PrimaryFields {
		if _, isZero := pf.ValueOf(value); isZero {
			return true
		}
	}
	return false
}

func InvalidCache(module, table string) {
	cacheLocker.Lock()
	delete(cached, table+"@"+module)
	cacheLocker.Unlock()
}

func VisibleField(module, table, scenario string, db *gorm.DB) []*Schema {
	var (
		ok     bool
		err    error
		sess   *gorm.DB
		values []*Schema
		result []*Schema
	)
	cacheLocker.RLock()
	values, ok = cached[table+"@"+module]
	cacheLocker.RUnlock()
	if ok {
		goto __end
	}
	values = make([]*Schema, 0)
	sess = db.Scopes(func(db *gorm.DB) *gorm.DB {
		s := db.Session(&gorm.Session{})
		s.Statement = newStatement(s)
		return s
	})
	if err = sess.Where("module_name=? AND table_name=?", module, table).Order("position,id ASC").Find(&values).Error; err != nil {
		return values
	}
	cacheLocker.Lock()
	cached[table+"@"+module] = values
	cacheLocker.Unlock()
__end:
	if scenario == "" {
		return values
	}
	result = make([]*Schema, 0)
	for _, model := range values {
		if strings.Index(model.Scenario, scenario) > -1 {
			result = append(result, model)
		}
	}
	return result
}

func extraSize(str string) int {
	var (
		sb   strings.Builder
		flag = -1
	)
	b := make([]byte, 0)
	b = append(b, str...)
	for _, s := range b {
		if s >= '0' && s <= '9' {
			if flag == -1 {
				flag = 1
			}
			sb.WriteByte(s)
		} else if flag == 1 {
			break
		}
	}
	v, _ := strconv.Atoi(sb.String())
	return v
}

func rules(field *schema.Field) string {
	r := &Rule{
		Required: []string{},
	}
	if field.GORMDataType == "string" {
		r.Max = extraSize(string(field.DataType))
	}
	if field.PrimaryKey {
		r.Unique = true
	}
	return r.String()
}

func migrate(module string, db *gorm.DB, val interface{}) (err error) {
	fields := make([]*Schema, 0)
	stmt := newStatement(db)
	if err = stmt.Parse(val); err != nil {
		return err
	}
	db.Model(&Schema{}).Find(&fields, "table_name=?", stmt.Table)
	err = db.Transaction(func(tx *gorm.DB) error {
		var (
			i         int
			format    string
			label     string
			fieldName string
			model     *Schema
			isExists  bool

			visible  string
			dataType string
			count    int
			enable   bool
		)
		for _, field := range stmt.Schema.Fields {
			fieldName = field.DBName
			if fieldName == "-" {
				continue
			}
			isExists = false
			if fieldName == "" {
				fieldName = field.Name
			}
			label = field.Tag.Get("comment")
			if label == "" {
				label = names(fieldName)
			}

			format = dataFormatOf(field)

			for _, fv := range fields {
				if fv.Column == fieldName {
					isExists = true
					break
				}
			}
			if isExists {
				continue
			}

			if bv, _ := json.Marshal([]string{scenario.Search, scenario.List, scenario.Create, scenario.Update, scenario.Export, scenario.View}); bv != nil {
				visible = string(bv)
			}
			if !array.In(field.Name, []string{"ID", "CreatedAt", "UpdatedAt", "DeletedAt"}) && count < 10 {
				count++
				enable = true
			} else {
				enable = false
			}
			dataType = strings.ToLower(dataTypeOf(field))
			model = &Schema{
				Module:   module,
				Table:    stmt.Table,
				Column:   fieldName,
				Enable:   enable,
				Label:    label,
				Type:     dataType,
				Format:   format,
				Options:  `{"readonly":[],"disable":[],"visible":[],"items":[],"lazy":{"enable":false,"type":"dropdown","url":""}}`,
				Scenario: visible,
				Rules:    rules(field),
				Position: i,
			}
			i++
			if err2 := tx.Save(model).Error; err2 != nil {
				return err2
			}
		}
		return nil
	})
	return
}

func Migrate(module string, db *gorm.DB, values ...interface{}) (err error) {
	for _, val := range values {
		if err = db.AutoMigrate(val); err == nil {
			if err = migrate(module, db, val); err != nil {
				return
			}
		}
	}
	return
}

func PrimaryKeyValue(statement *gorm.Statement) interface{} {
	var (
		field    *schema.Field
		refValue reflect.Value
	)
	if len(statement.Schema.PrimaryFields) > 0 {
		field = statement.Schema.PrimaryFields[0]
		refValue = statement.ReflectValue.FieldByName(field.Name)
		if refValue.IsValid() && !refValue.IsZero() {
			return refValue.Interface()
		}
	}
	return nil
}

func Initialize(ctx context.Context, db *gorm.DB, svr *http.Server) (err error) {
	if db != nil {
		if err = db.AutoMigrate(&Schema{}); err != nil {
			return
		}
	}
	if svr != nil && db != nil {
		routes(db, svr)
	}
	return
}