package request

import (
	"errors"
	"net/url"
	"reflect"
	"strconv"
	"strings"
)

// Bind data from request.Form[key] to dest
// like /?id=123&isok=true&ft=1.2&ol[0]=1&ol[1]=2&ul[]=str&ul[]=array&user.Name=orange
// var id int  orangeInput.Bind(&id, "id")  id ==123
// var isok bool  orangeInput.Bind(&isok, "isok")  isok ==true
// var ft float64  orangeInput.Bind(&ft, "ft")  ft ==1.2
// ol := make([]int, 0, 2)  orangeInput.Bind(&ol, "ol")  ol ==[1 2]
// ul := make([]string, 0, 2)  orangeInput.Bind(&ul, "ul")  ul ==[str array]
// user struct{Name}  orangeInput.Bind(&user, "user")  user == {Name:"orange"}
func (input *OrangeInput) Bind(dest interface{}, key string) error {
	value := reflect.ValueOf(dest)
	if value.Kind() != reflect.Ptr {
		return errors.New("orange: non-pointer passed to Bind: " + key)
	}
	value = value.Elem()
	if !value.CanSet() {
		return errors.New("orange: non-settable variable passed to Bind: " + key)
	}
	typ := value.Type()
	// Get real type if dest define with interface{}.
	// e.g  var dest interface{} dest=1.0
	if value.Kind() == reflect.Interface {
		typ = value.Elem().Type()
	}
	rv := input.bind(key, typ)
	if !rv.IsValid() {
		return errors.New("orange: reflect value is empty")
	}
	value.Set(rv)
	return nil
}

func (input *OrangeInput) bind(key string, typ reflect.Type) reflect.Value {
	if input.request.Form == nil {
		input.request.ParseForm()
	}
	rv := reflect.Zero(typ)
	switch typ.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		val := input.Query(key)
		if len(val) == 0 {
			return rv
		}
		rv = input.bindInt(val, typ)
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		val := input.Query(key)
		if len(val) == 0 {
			return rv
		}
		rv = input.bindUint(val, typ)
	case reflect.Float32, reflect.Float64:
		val := input.Query(key)
		if len(val) == 0 {
			return rv
		}
		rv = input.bindFloat(val, typ)
	case reflect.String:
		val := input.Query(key)
		if len(val) == 0 {
			return rv
		}
		rv = input.bindString(val, typ)
	case reflect.Bool:
		val := input.Query(key)
		if len(val) == 0 {
			return rv
		}
		rv = input.bindBool(val, typ)
	case reflect.Slice:
		rv = input.bindSlice(&input.request.Form, key, typ)
	case reflect.Struct:
		rv = input.bindStruct(&input.request.Form, key, typ)
	case reflect.Ptr:
		rv = input.bindPoint(key, typ)
	case reflect.Map:
		rv = input.bindMap(&input.request.Form, key, typ)
	}
	return rv
}

func (input *OrangeInput) bindValue(val string, typ reflect.Type) reflect.Value {
	rv := reflect.Zero(typ)
	switch typ.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		rv = input.bindInt(val, typ)
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		rv = input.bindUint(val, typ)
	case reflect.Float32, reflect.Float64:
		rv = input.bindFloat(val, typ)
	case reflect.String:
		rv = input.bindString(val, typ)
	case reflect.Bool:
		rv = input.bindBool(val, typ)
	case reflect.Slice:
		rv = input.bindSlice(&url.Values{"": {val}}, "", typ)
	case reflect.Struct:
		rv = input.bindStruct(&url.Values{"": {val}}, "", typ)
	case reflect.Ptr:
		rv = input.bindPoint(val, typ)
	case reflect.Map:
		rv = input.bindMap(&url.Values{"": {val}}, "", typ)
	}
	return rv
}

func (input *OrangeInput) bindInt(val string, typ reflect.Type) reflect.Value {
	intValue, err := strconv.ParseInt(val, 10, 64)
	if err != nil {
		return reflect.Zero(typ)
	}
	pValue := reflect.New(typ)
	pValue.Elem().SetInt(intValue)
	return pValue.Elem()
}

func (input *OrangeInput) bindUint(val string, typ reflect.Type) reflect.Value {
	uintValue, err := strconv.ParseUint(val, 10, 64)
	if err != nil {
		return reflect.Zero(typ)
	}
	pValue := reflect.New(typ)
	pValue.Elem().SetUint(uintValue)
	return pValue.Elem()
}

func (input *OrangeInput) bindFloat(val string, typ reflect.Type) reflect.Value {
	floatValue, err := strconv.ParseFloat(val, 64)
	if err != nil {
		return reflect.Zero(typ)
	}
	pValue := reflect.New(typ)
	pValue.Elem().SetFloat(floatValue)
	return pValue.Elem()
}

func (input *OrangeInput) bindString(val string, typ reflect.Type) reflect.Value {
	return reflect.ValueOf(val)
}

func (input *OrangeInput) bindBool(val string, typ reflect.Type) reflect.Value {
	val = strings.TrimSpace(strings.ToLower(val))
	switch val {
	case "true", "on", "1":
		return reflect.ValueOf(true)
	}
	return reflect.ValueOf(false)
}

type sliceValue struct {
	index int           // Index extracted from brackets.  If -1, no index was provided.
	value reflect.Value // the bound value for this slice element.
}

func (input *OrangeInput) bindSlice(params *url.Values, key string, typ reflect.Type) reflect.Value {
	maxIndex := -1
	numNoIndex := 0
	sliceValues := []sliceValue{}
	for reqKey, vals := range *params {
		if !strings.HasPrefix(reqKey, key+"[") {
			continue
		}
		// Extract the index, and the index where a sub-key starts. (e.g. field[0].subkey)
		index := -1
		leftBracket, rightBracket := len(key), strings.Index(reqKey[len(key):], "]")+len(key)
		if rightBracket > leftBracket+1 {
			index, _ = strconv.Atoi(reqKey[leftBracket+1 : rightBracket])
		}
		subKeyIndex := rightBracket + 1

		// Handle the indexed case.
		if index > -1 {
			if index > maxIndex {
				maxIndex = index
			}
			sliceValues = append(sliceValues, sliceValue{
				index: index,
				value: input.bind(reqKey[:subKeyIndex], typ.Elem()),
			})
			continue
		}

		// It's an un-indexed element.  (e.g. element[])
		numNoIndex += len(vals)
		for _, val := range vals {
			// Unindexed values can only be direct-bound.
			sliceValues = append(sliceValues, sliceValue{
				index: -1,
				value: input.bindValue(val, typ.Elem()),
			})
		}
	}
	resultArray := reflect.MakeSlice(typ, maxIndex+1, maxIndex+1+numNoIndex)
	for _, sv := range sliceValues {
		if sv.index != -1 {
			resultArray.Index(sv.index).Set(sv.value)
		} else {
			resultArray = reflect.Append(resultArray, sv.value)
		}
	}
	return resultArray
}

func (input *OrangeInput) bindStruct(params *url.Values, key string, typ reflect.Type) reflect.Value {
	result := reflect.New(typ).Elem()
	fieldValues := make(map[string]reflect.Value)
	for reqKey, val := range *params {
		var fieldName string
		if strings.HasPrefix(reqKey, key+".") {
			fieldName = reqKey[len(key)+1:]
		} else if strings.HasPrefix(reqKey, key+"[") && reqKey[len(reqKey)-1] == ']' {
			fieldName = reqKey[len(key)+1 : len(reqKey)-1]
		} else {
			continue
		}

		if _, ok := fieldValues[fieldName]; !ok {
			// Time to bind this field.  Get it and make sure we can set it.
			fieldValue := result.FieldByName(fieldName)
			if !fieldValue.IsValid() {
				continue
			}
			if !fieldValue.CanSet() {
				continue
			}
			boundVal := input.bindValue(val[0], fieldValue.Type())
			fieldValue.Set(boundVal)
			fieldValues[fieldName] = boundVal
		}
	}

	return result
}

func (input *OrangeInput) bindPoint(key string, typ reflect.Type) reflect.Value {
	return input.bind(key, typ.Elem()).Addr()
}

func (input *OrangeInput) bindMap(params *url.Values, key string, typ reflect.Type) reflect.Value {
	var (
		result    = reflect.MakeMap(typ)
		keyType   = typ.Key()
		valueType = typ.Elem()
	)
	for paramName, values := range *params {
		if !strings.HasPrefix(paramName, key+"[") || paramName[len(paramName)-1] != ']' {
			continue
		}

		key := paramName[len(key)+1 : len(paramName)-1]
		result.SetMapIndex(input.bindValue(key, keyType), input.bindValue(values[0], valueType))
	}
	return result
}