// Copyright 2014 beego Author. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package orm

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

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

// field info collection
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
}

// add field info
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 {
		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
}

// get field info by name
func (f *fields) GetByName(name string) *fieldInfo {
	return f.fields[name]
}

// get field info by column name
func (f *fields) GetByColumn(column string) *fieldInfo {
	return f.columns[column]
}

// get field info by string, name is prior
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
}

// create new field info collection
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
}

// single field info
type fieldInfo struct {
	mi                  *modelInfo
	fieldIndex          []int
	fieldType           int
	dbcol               bool // table column fk and onetoone
	inModel             bool
	name                string
	fullName            string
	column              string
	addrValue           reflect.Value
	sf                  reflect.StructField
	auto                bool
	pk                  bool
	null                bool
	index               bool
	unique              bool
	colDefault          bool  // whether has default tag
	initial             StrTo // store the default value
	size                int
	toText              bool
	autoNow             bool
	autoNowAdd          bool
	rel                 bool // if type equal to RelForeignKey, RelOneToOne, RelManyToMany then true
	reverse             bool
	reverseField        string
	reverseFieldInfo    *fieldInfo
	reverseFieldInfoTwo *fieldInfo
	reverseFieldInfoM2M *fieldInfo
	relTable            string
	relThrough          string
	relThroughModelInfo *modelInfo
	relModelInfo        *modelInfo
	digits              int
	decimals            int
	isFielder           bool // implement Fielder interface
	onDelete            string
}

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

	fi = new(fieldInfo)

	// if field which CanAddr is the follow type
	//  A value is addressable if it is an element of a slice,
	//  an element of an addressable array, a field of an
	//  addressable struct, or the result of dereferencing a pointer.
	addrField = field
	if field.CanAddr() && field.Kind() != reflect.Ptr {
		addrField = field.Addr()
		if _, ok := addrField.Interface().(Fielder); !ok {
			if field.Kind() == reflect.Slice {
				addrField = field
			}
		}
	}

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

	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 type custom field, please refer to https://github.com/astaxie/beego/blob/master/orm/models_fields.go#L24-L42")
			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("rel only allow these value: fk, one, m2m")
				goto wrongTag
			}
		}
		tag = "reverse"
		tagValue = tags[tag]
		if tagValue != "" {
			switch tagValue {
			case "one":
				fieldType = RelReverseOne
				break checkType
			case "many":
				fieldType = RelReverseMany
				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("reverse only allow these value: one, many")
				goto wrongTag
			}
		}

		fieldType, err = getFieldType(addrField)
		if err != nil {
			goto end
		}
		if fieldType == TypeVarCharField {
			switch tags["type"] {
			case "char":
				fieldType = TypeCharField
			case "text":
				fieldType = TypeTextField
			case "json":
				fieldType = TypeJSONField
			case "jsonb":
				fieldType = TypeJsonbField
			}
		}
		if fieldType == TypeFloatField && (digits != "" || decimals != "") {
			fieldType = TypeDecimalField
		}
		if fieldType == TypeDateTimeField && tags["type"] == "date" {
			fieldType = TypeDateField
		}
		if fieldType == TypeTimeField && tags["type"] == "time" {
			fieldType = TypeTimeField
		}
	}

	// check the rel and reverse type
	// rel should Ptr
	// reverse should slice []*struct
	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 + mName + "." + sf.Name

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

	// Mark object property if there is attribute "default" in the orm configuration
	if _, ok := tags["default"]; ok {
		fi.colDefault = true
	}

	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 odCascade, odDoNothing:
		case odSetDefault:
			if !initial.Exist() {
				err = errors.New("on_delete: set_default need set field a default value")
				goto end
			}
		case odSetNULL:
			if !fi.null {
				err = errors.New("on_delete: set_null need set field null")
				goto end
			}
		default:
			if onDelete == "" {
				onDelete = odCascade
			} 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 TypeVarCharField, TypeCharField, TypeJSONField, TypeJsonbField:
		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
			fi.toText = true
		}
	case TypeTextField:
		fi.index = false
		fi.unique = false
	case TypeTimeField, TypeDateField, TypeDateTimeField:
		if attrs["auto_now"] {
			fi.autoNow = true
		} else if attrs["auto_now_add"] {
			fi.autoNowAdd = 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.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
	}

	// can not set default for these type
	if fi.auto || fi.pk || fi.unique || fieldType == TypeTimeField || fieldType == TypeDateField || fieldType == TypeDateTimeField {
		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)
}
