package gorm

import (
	"errors"
	"fmt"
	"strings"
	"time"

	"reflect"
)

type Scope struct {
	Value           interface{}
	indirectValue   *reflect.Value
	Search          *search
	Sql             string
	SqlVars         []interface{}
	db              *DB
	skipLeft        bool
	primaryKeyField *Field
	instanceId      string
	fields          map[string]*Field
}

func (scope *Scope) IndirectValue() reflect.Value {
	if scope.indirectValue == nil {
		value := reflect.Indirect(reflect.ValueOf(scope.Value))
		scope.indirectValue = &value
	}
	return *scope.indirectValue
}

// NewScope create scope for callbacks, including DB's search information
func (db *DB) NewScope(value interface{}) *Scope {
	db.Value = value
	return &Scope{db: db, Search: db.search, Value: value}
}

func (scope *Scope) NeedPtr() *Scope {
	reflectKind := reflect.ValueOf(scope.Value).Kind()
	if !((reflectKind == reflect.Invalid) || (reflectKind == reflect.Ptr)) {
		err := errors.New(fmt.Sprintf("%v %v\n", fileWithLineNum(), "using unaddressable value"))
		scope.Err(err)
		fmt.Printf(err.Error())
	}
	return scope
}

// New create a new Scope without search information
func (scope *Scope) New(value interface{}) *Scope {
	return &Scope{db: scope.db, Search: &search{}, Value: value}
}

// NewDB create a new DB without search information
func (scope *Scope) NewDB() *DB {
	return scope.db.New()
}

// DB get *sql.DB
func (scope *Scope) DB() sqlCommon {
	return scope.db.db
}

// SkipLeft skip remaining callbacks
func (scope *Scope) SkipLeft() {
	scope.skipLeft = true
}

// Quote used to quote database column name according to database dialect
func (scope *Scope) Quote(str string) string {
	return scope.Dialect().Quote(str)
}

// Dialect get dialect
func (scope *Scope) Dialect() Dialect {
	return scope.db.parent.dialect
}

// Err write error
func (scope *Scope) Err(err error) error {
	if err != nil {
		scope.db.err(err)
	}
	return err
}

// Log print log message
func (scope *Scope) Log(v ...interface{}) {
	scope.db.log(v...)
}

// HasError check if there are any error
func (scope *Scope) HasError() bool {
	return scope.db.Error != nil
}

func (scope *Scope) PrimaryKeyField() *Field {
	if scope.primaryKeyField == nil {
		var indirectValue = scope.IndirectValue()

		clone := scope
		// FIXME
		if indirectValue.Kind() == reflect.Slice {
			typ := indirectValue.Type().Elem()
			if typ.Kind() == reflect.Ptr {
				typ = typ.Elem()
			}
			clone = scope.New(reflect.New(typ).Elem().Addr().Interface())
		}

		for _, field := range clone.Fields() {
			if field.IsPrimaryKey {
				scope.primaryKeyField = field
				break
			}
		}
	}

	return scope.primaryKeyField
}

// PrimaryKey get the primary key's column name
func (scope *Scope) PrimaryKey() string {
	if field := scope.PrimaryKeyField(); field != nil {
		return field.DBName
	} else {
		return ""
	}
}

// PrimaryKeyZero check the primary key is blank or not
func (scope *Scope) PrimaryKeyZero() bool {
	return isBlank(reflect.ValueOf(scope.PrimaryKeyValue()))
}

// PrimaryKeyValue get the primary key's value
func (scope *Scope) PrimaryKeyValue() interface{} {
	if field := scope.PrimaryKeyField(); field != nil {
		return field.Field.Interface()
	} else {
		return 0
	}
}

// HasColumn to check if has column
func (scope *Scope) HasColumn(column string) bool {
	clone := scope
	if scope.IndirectValue().Kind() == reflect.Slice {
		value := reflect.New(scope.IndirectValue().Type().Elem()).Interface()
		clone = scope.New(value)
	}

	dbName := ToSnake(column)

	field, hasColumn := clone.Fields()[dbName]
	return hasColumn && !field.IsIgnored
}

// FieldValueByName to get column's value and existence
func (scope *Scope) FieldValueByName(name string) (interface{}, error) {
	return FieldValueByName(name, scope.Value)
}

// SetColumn to set the column's value
func (scope *Scope) SetColumn(column interface{}, value interface{}) error {
	if field, ok := column.(*Field); ok {
		return field.Set(value)
	} else if dbName, ok := column.(string); ok {
		if scope.Value == nil {
			return errors.New("scope value must not be nil for string columns")
		}

		if field, ok := scope.Fields()[dbName]; ok {
			return field.Set(value)
		}

		dbName = ToSnake(dbName)

		if field, ok := scope.Fields()[dbName]; ok {
			return field.Set(value)
		}
	}
	return errors.New("could not convert column to field")
}

// CallMethod invoke method with necessary argument
func (scope *Scope) CallMethod(name string) {
	if scope.Value == nil {
		return
	}

	call := func(value interface{}) {
		if fm := reflect.ValueOf(value).MethodByName(name); fm.IsValid() {
			switch f := fm.Interface().(type) {
			case func():
				f()
			case func(s *Scope):
				f(scope)
			case func(s *DB):
				f(scope.db.New())
			case func() error:
				scope.Err(f())
			case func(s *Scope) error:
				scope.Err(f(scope))
			case func(s *DB) error:
				scope.Err(f(scope.db.New()))
			default:
				scope.Err(errors.New(fmt.Sprintf("unsupported function %v", name)))
			}
		}
	}

	if values := scope.IndirectValue(); values.Kind() == reflect.Slice {
		for i := 0; i < values.Len(); i++ {
			call(values.Index(i).Addr().Interface())
		}
	} else {
		call(scope.Value)
	}
}

// AddToVars add value as sql's vars, gorm will escape them
func (scope *Scope) AddToVars(value interface{}) string {
	scope.SqlVars = append(scope.SqlVars, value)
	return scope.Dialect().BinVar(len(scope.SqlVars))
}

// TableName get table name

func (scope *Scope) TableName() string {
	if scope.Search != nil && len(scope.Search.TableName) > 0 {
		return scope.Search.TableName
	} else {
		if scope.Value == nil {
			scope.Err(errors.New("can't get table name"))
			return ""
		}

		data := scope.IndirectValue()
		if data.Kind() == reflect.Slice {
			elem := data.Type().Elem()
			if elem.Kind() == reflect.Ptr {
				elem = elem.Elem()
			}
			data = reflect.New(elem).Elem()
		}

		if fm := data.MethodByName("TableName"); fm.IsValid() {
			if v := fm.Call([]reflect.Value{}); len(v) > 0 {
				if result, ok := v[0].Interface().(string); ok {
					return result
				}
			}
		}

		str := ToSnake(data.Type().Name())

		if scope.db == nil || !scope.db.parent.singularTable {
			for index, reg := range pluralMapKeys {
				if reg.MatchString(str) {
					return reg.ReplaceAllString(str, pluralMapValues[index])
				}
			}
		}

		return str
	}
}

func (scope *Scope) QuotedTableName() string {
	if scope.Search != nil && len(scope.Search.TableName) > 0 {
		return scope.Search.TableName
	} else {
		keys := strings.Split(scope.TableName(), ".")
		for i, v := range keys {
			keys[i] = scope.Quote(v)
		}
		return strings.Join(keys, ".")
	}
}

// CombinedConditionSql get combined condition sql
func (scope *Scope) CombinedConditionSql() string {
	return scope.joinsSql() + scope.whereSql() + scope.groupSql() +
		scope.havingSql() + scope.orderSql() + scope.limitSql() + scope.offsetSql()
}

func (scope *Scope) FieldByName(name string) (field *Field, ok bool) {
	for _, field := range scope.Fields() {
		if field.Name == name {
			return field, true
		}
	}
	return nil, false
}

// Fields get value's fields
func (scope *Scope) Fields() map[string]*Field {
	fields := map[string]*Field{}
	structFields := scope.GetStructFields()
	for _, structField := range structFields {
		field := Field{StructField: structField}
		fields[field.DBName] = &field
	}

	return fields
}

// Raw set sql
func (scope *Scope) Raw(sql string) *Scope {
	scope.Sql = strings.Replace(sql, "$$", "?", -1)
	return scope
}

// Exec invoke sql
func (scope *Scope) Exec() *Scope {
	defer scope.Trace(NowFunc())

	if !scope.HasError() {
		result, err := scope.DB().Exec(scope.Sql, scope.SqlVars...)
		if scope.Err(err) == nil {
			if count, err := result.RowsAffected(); err == nil {
				scope.db.RowsAffected = count
			}
		}
	}
	return scope
}

// Set set value by name
func (scope *Scope) Set(name string, value interface{}) *Scope {
	scope.db.InstantSet(name, value)
	return scope
}

// Get get value by name
func (scope *Scope) Get(name string) (interface{}, bool) {
	return scope.db.Get(name)
}

// InstanceId get InstanceId for scope
func (scope *Scope) InstanceId() string {
	if scope.instanceId == "" {
		scope.instanceId = fmt.Sprintf("%v%v", &scope, &scope.db)
	}
	return scope.instanceId
}

func (scope *Scope) InstanceSet(name string, value interface{}) *Scope {
	return scope.Set(name+scope.InstanceId(), value)
}

func (scope *Scope) InstanceGet(name string) (interface{}, bool) {
	return scope.Get(name + scope.InstanceId())
}

// Trace print sql log
func (scope *Scope) Trace(t time.Time) {
	if len(scope.Sql) > 0 {
		scope.db.slog(scope.Sql, t, scope.SqlVars...)
	}
}

// Begin start a transaction
func (scope *Scope) Begin() *Scope {
	if db, ok := scope.DB().(sqlDb); ok {
		if tx, err := db.Begin(); err == nil {
			scope.db.db = interface{}(tx).(sqlCommon)
			scope.InstanceSet("gorm:started_transaction", true)
		}
	}
	return scope
}

// CommitOrRollback commit current transaction if there is no error, otherwise rollback it
func (scope *Scope) CommitOrRollback() *Scope {
	if _, ok := scope.InstanceGet("gorm:started_transaction"); ok {
		if db, ok := scope.db.db.(sqlTx); ok {
			if scope.HasError() {
				db.Rollback()
			} else {
				db.Commit()
			}
			scope.db.db = scope.db.parent.db
		}
	}
	return scope
}