package orm

import (
	"errors"
	"fmt"
	"reflect"
	"strings"
)

var errSkipField = errors.New("skip field")

type fields struct {
	pk            *fieldInfo
	columns       map[string]*fieldInfo
	fields        map[string]*fieldInfo
	fieldsLow     map[string]*fieldInfo
	fieldsByType  map[int][]*fieldInfo
	fieldsRel     []*fieldInfo
	fieldsReverse []*fieldInfo
	fieldsDB      []*fieldInfo
	rels          []*fieldInfo
	orders        []string
	dbcols        []string
}

func (f *fields) Add(fi *fieldInfo) (added bool) {
	if f.fields[fi.name] == nil && f.columns[fi.column] == nil {
		f.columns[fi.column] = fi
		f.fields[fi.name] = fi
		f.fieldsLow[strings.ToLower(fi.name)] = fi
	} else {
		return
	}
	if _, ok := f.fieldsByType[fi.fieldType]; ok == false {
		f.fieldsByType[fi.fieldType] = make([]*fieldInfo, 0)
	}
	f.fieldsByType[fi.fieldType] = append(f.fieldsByType[fi.fieldType], fi)
	f.orders = append(f.orders, fi.column)
	if fi.dbcol {
		f.dbcols = append(f.dbcols, fi.column)
		f.fieldsDB = append(f.fieldsDB, fi)
	}
	if fi.rel {
		f.fieldsRel = append(f.fieldsRel, fi)
	}
	if fi.reverse {
		f.fieldsReverse = append(f.fieldsReverse, fi)
	}
	return true
}

func (f *fields) GetByName(name string) *fieldInfo {
	return f.fields[name]
}

func (f *fields) GetByColumn(column string) *fieldInfo {
	return f.columns[column]
}

func (f *fields) GetByAny(name string) (*fieldInfo, bool) {
	if fi, ok := f.fields[name]; ok {
		return fi, ok
	}
	if fi, ok := f.fieldsLow[strings.ToLower(name)]; ok {
		return fi, ok
	}
	if fi, ok := f.columns[name]; ok {
		return fi, ok
	}
	return nil, false
}

func newFields() *fields {
	f := new(fields)
	f.fields = make(map[string]*fieldInfo)
	f.fieldsLow = make(map[string]*fieldInfo)
	f.columns = make(map[string]*fieldInfo)
	f.fieldsByType = make(map[int][]*fieldInfo)
	return f
}

type fieldInfo struct {
	mi                  *modelInfo
	fieldIndex          int
	fieldType           int
	dbcol               bool
	inModel             bool
	name                string
	fullName            string
	column              string
	addrValue           reflect.Value
	sf                  reflect.StructField
	auto                bool
	pk                  bool
	null                bool
	index               bool
	unique              bool
	initial             StrTo
	size                int
	auto_now            bool
	auto_now_add        bool
	rel                 bool
	reverse             bool
	reverseField        string
	reverseFieldInfo    *fieldInfo
	relTable            string
	relThrough          string
	relThroughModelInfo *modelInfo
	relModelInfo        *modelInfo
	digits              int
	decimals            int
	isFielder           bool
	onDelete            string
}

func newFieldInfo(mi *modelInfo, field reflect.Value, sf reflect.StructField) (fi *fieldInfo, err error) {
	var (
		tag       string
		tagValue  string
		initial   StrTo
		fieldType int
		attrs     map[string]bool
		tags      map[string]string
		addrField reflect.Value
	)

	fi = new(fieldInfo)

	if field.Kind() != reflect.Ptr && field.Kind() != reflect.Slice && field.CanAddr() {
		addrField = field.Addr()
	} else {
		addrField = field
	}

	parseStructTag(sf.Tag.Get(defaultStructTagName), &attrs, &tags)

	if _, ok := attrs["-"]; ok {
		return nil, errSkipField
	}

	digits := tags["digits"]
	decimals := tags["decimals"]
	size := tags["size"]
	onDelete := tags["on_delete"]

	initial.Clear()
	if v, ok := tags["default"]; ok {
		initial.Set(v)
	}

checkType:
	switch f := addrField.Interface().(type) {
	case Fielder:
		fi.isFielder = true
		if field.Kind() == reflect.Ptr {
			err = fmt.Errorf("the model Fielder can not be use ptr")
			goto end
		}
		fieldType = f.FieldType()
		if fieldType&IsRelField > 0 {
			err = fmt.Errorf("unsupport rel type custom field")
			goto end
		}
	default:
		tag = "rel"
		tagValue = tags[tag]
		if tagValue != "" {
			switch tagValue {
			case "fk":
				fieldType = RelForeignKey
				break checkType
			case "one":
				fieldType = RelOneToOne
				break checkType
			case "m2m":
				fieldType = RelManyToMany
				if tv := tags["rel_table"]; tv != "" {
					fi.relTable = tv
				} else if tv := tags["rel_through"]; tv != "" {
					fi.relThrough = tv
				}
				break checkType
			default:
				err = fmt.Errorf("error")
				goto wrongTag
			}
		}
		tag = "reverse"
		tagValue = tags[tag]
		if tagValue != "" {
			switch tagValue {
			case "one":
				fieldType = RelReverseOne
				break checkType
			case "many":
				fieldType = RelReverseMany
				break checkType
			default:
				err = fmt.Errorf("error")
				goto wrongTag
			}
		}

		fieldType, err = getFieldType(addrField)
		if err != nil {
			goto end
		}
		if fieldType == TypeCharField && tags["type"] == "text" {
			fieldType = TypeTextField
		}
		if fieldType == TypeFloatField && (digits != "" || decimals != "") {
			fieldType = TypeDecimalField
		}
		if fieldType == TypeDateTimeField && tags["type"] == "date" {
			fieldType = TypeDateField
		}
	}

	switch fieldType {
	case RelForeignKey, RelOneToOne, RelReverseOne:
		if field.Kind() != reflect.Ptr {
			err = fmt.Errorf("rel/reverse:one field must be *%s", field.Type().Name())
			goto end
		}
	case RelManyToMany, RelReverseMany:
		if field.Kind() != reflect.Slice {
			err = fmt.Errorf("rel/reverse:many field must be slice")
			goto end
		} else {
			if field.Type().Elem().Kind() != reflect.Ptr {
				err = fmt.Errorf("rel/reverse:many slice must be []*%s", field.Type().Elem().Name())
				goto end
			}
		}
	}

	if fieldType&IsFieldType == 0 {
		err = fmt.Errorf("wrong field type")
		goto end
	}

	fi.fieldType = fieldType
	fi.name = sf.Name
	fi.column = getColumnName(fieldType, addrField, sf, tags["column"])
	fi.addrValue = addrField
	fi.sf = sf
	fi.fullName = mi.fullName + "." + sf.Name

	fi.null = attrs["null"]
	fi.index = attrs["index"]
	fi.auto = attrs["auto"]
	fi.pk = attrs["pk"]
	fi.unique = attrs["unique"]

	switch fieldType {
	case RelManyToMany, RelReverseMany, RelReverseOne:
		fi.null = false
		fi.index = false
		fi.auto = false
		fi.pk = false
		fi.unique = false
	default:
		fi.dbcol = true
	}

	switch fieldType {
	case RelForeignKey, RelOneToOne, RelManyToMany:
		fi.rel = true
		if fieldType == RelOneToOne {
			fi.unique = true
		}
	case RelReverseMany, RelReverseOne:
		fi.reverse = true
	}

	if fi.rel && fi.dbcol {
		switch onDelete {
		case od_CASCADE, od_DO_NOTHING:
		case od_SET_DEFAULT:
			if initial.Exist() == false {
				err = errors.New("on_delete: set_default need set field a default value")
				goto end
			}
		case od_SET_NULL:
			if fi.null == false {
				err = errors.New("on_delete: set_null need set field null")
				goto end
			}
		default:
			if onDelete == "" {
				onDelete = od_CASCADE
			} else {
				err = fmt.Errorf("on_delete value expected choice in `cascade,set_null,set_default,do_nothing`, unknown `%s`", onDelete)
				goto end
			}
		}

		fi.onDelete = onDelete
	}

	switch fieldType {
	case TypeBooleanField:
	case TypeCharField:
		if size != "" {
			v, e := StrTo(size).Int32()
			if e != nil {
				err = fmt.Errorf("wrong size value `%s`", size)
			} else {
				fi.size = int(v)
			}
		} else {
			fi.size = 255
		}
	case TypeTextField:
		fi.index = false
		fi.unique = false
	case TypeDateField, TypeDateTimeField:
		if attrs["auto_now"] {
			fi.auto_now = true
		} else if attrs["auto_now_add"] {
			fi.auto_now_add = true
		}
	case TypeFloatField:
	case TypeDecimalField:
		d1 := digits
		d2 := decimals
		v1, er1 := StrTo(d1).Int8()
		v2, er2 := StrTo(d2).Int8()
		if er1 != nil || er2 != nil {
			err = fmt.Errorf("wrong digits/decimals value %s/%s", d2, d1)
			goto end
		}
		fi.digits = int(v1)
		fi.decimals = int(v2)
	default:
		switch {
		case fieldType&IsIntegerField > 0:
		case fieldType&IsRelField > 0:
		}
	}

	if fieldType&IsIntegerField == 0 {
		if fi.auto {
			err = fmt.Errorf("non-integer type cannot set auto")
			goto end
		}

		if fi.pk || fi.index || fi.unique {
			if fieldType != TypeCharField && fieldType != RelOneToOne {
				err = fmt.Errorf("cannot set pk/index/unique")
				goto end
			}
		}
	}

	if fi.auto || fi.pk {
		if fi.auto {

			switch addrField.Elem().Kind() {
			case reflect.Int, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint32, reflect.Uint64:
			default:
				err = fmt.Errorf("auto primary key only support int, int32, int64, uint, uint32, uint64 but found `%s`", addrField.Elem().Kind())
				goto end
			}

			fi.pk = true
		}
		fi.null = false
		fi.index = false
		fi.unique = false
	}

	if fi.unique {
		fi.index = false
	}

	if fi.auto || fi.pk || fi.unique || fieldType == TypeDateField || fieldType == TypeDateTimeField {
		// can not set default
		initial.Clear()
	}

	if initial.Exist() {
		v := initial
		switch fieldType {
		case TypeBooleanField:
			_, err = v.Bool()
		case TypeFloatField, TypeDecimalField:
			_, err = v.Float64()
		case TypeBitField:
			_, err = v.Int8()
		case TypeSmallIntegerField:
			_, err = v.Int16()
		case TypeIntegerField:
			_, err = v.Int32()
		case TypeBigIntegerField:
			_, err = v.Int64()
		case TypePositiveBitField:
			_, err = v.Uint8()
		case TypePositiveSmallIntegerField:
			_, err = v.Uint16()
		case TypePositiveIntegerField:
			_, err = v.Uint32()
		case TypePositiveBigIntegerField:
			_, err = v.Uint64()
		}
		if err != nil {
			tag, tagValue = "default", tags["default"]
			goto wrongTag
		}
	}

	fi.initial = initial
end:
	if err != nil {
		return nil, err
	}
	return
wrongTag:
	return nil, fmt.Errorf("wrong tag format: `%s:\"%s\"`, %s", tag, tagValue, err)
}