package web

import (
	"encoding/json"
	"fmt"
	"github.com/gin-gonic/gin"
	"io"
	"reflect"
	"strconv"
	"strings"
)

type IContext interface {
	HandleError(path string, err error)
	HandleSuccess(rspData any)
}

type HandlerFunc any

type RoutesGroup struct {
	newContextFun func(ctx *gin.Context) IContext
	rawGroup      *gin.RouterGroup
	node          *routesNode
}

func newRoutesGroup(rawGroup *gin.RouterGroup, newContextFun func(ctx *gin.Context) IContext) *RoutesGroup {
	g := &RoutesGroup{
		rawGroup:      rawGroup,
		newContextFun: newContextFun,
		node:          &routesNode{},
	}
	return g
}

func (group *RoutesGroup) Group(path string, desc string, handlers ...HandlerFunc) *RoutesGroup {
	rawGroup := group.rawGroup.Group(path, getGinHandlerFunWithRequest(group.newContextFun, handlers...)...)
	nextRoutesGroup := newRoutesGroup(rawGroup, group.newContextFun)
	nextGroupNode := group.addChildren("", path, desc, 0, handlers...)
	nextRoutesGroup.node = nextGroupNode
	return nextRoutesGroup
}

func (group *RoutesGroup) Use(middlewares ...HandlerFunc) {
	group.rawGroup.Use(getGinHandlerFunWithRequest(group.newContextFun, middlewares...)...)
}

func (group *RoutesGroup) Get(path string, desc string, permit int, handlers ...HandlerFunc) {
	group.rawGroup.GET(path, getGinHandlerFunWithRequest(group.newContextFun, handlers...)...)
	group.addChildren("GET", path, desc, permit, handlers...)
}

func (group *RoutesGroup) Post(path string, desc string, permit int, handlers ...HandlerFunc) {
	group.rawGroup.POST(path, getGinHandlerFunWithRequest(group.newContextFun, handlers...)...)
	group.addChildren("POST", path, desc, permit, handlers...)
}

func (group *RoutesGroup) Put(path string, desc string, permit int, handlers ...HandlerFunc) {
	group.rawGroup.PUT(path, getGinHandlerFunWithRequest(group.newContextFun, handlers...)...)
	group.addChildren("PUT", path, desc, permit, handlers...)
}

func (group *RoutesGroup) Delete(path string, desc string, permit int, handlers ...HandlerFunc) {
	group.rawGroup.DELETE(path, getGinHandlerFunWithRequest(group.newContextFun, handlers...)...)
	group.addChildren("DELETE", path, desc, permit, handlers...)
}

func (group *RoutesGroup) addChildren(method, path string, desc string, permit int, handlers ...HandlerFunc) *routesNode {
	return group.node.addChildren(method, path, desc, permit, handlers...)
}

func getGinHandlerFunWithRequest(newContextFun func(ctx *gin.Context) IContext, handlers ...HandlerFunc) []gin.HandlerFunc {
	list := make([]gin.HandlerFunc, 0, len(handlers))

	for _, handler := range handlers {
		list = append(list, func(rawCtx *gin.Context) {

			ctx := newContextFun(rawCtx)

			handlerTo := reflect.TypeOf(handler)
			numParams := handlerTo.NumIn()
			if numParams != 3 {
				ctx.HandleError(rawCtx.Request.RequestURI, fmt.Errorf("register callback handler params len(%v) invalid", numParams))
				return
			}

			paramsTo := handlerTo.In(1)
			params := reflect.New(paramsTo.Elem()).Interface()
			err := parseRequest(rawCtx, params)
			if err != nil {
				ctx.HandleError(rawCtx.Request.RequestURI, err)
				return
			}
			rspTo := handlerTo.In(2)
			rsp := reflect.New(rspTo.Elem()).Interface()
			rets := reflect.ValueOf(handler).Call([]reflect.Value{reflect.ValueOf(ctx), reflect.ValueOf(params), reflect.ValueOf(rsp)})
			errInt := rets[0]
			if errInt.Interface() == nil {
				ctx.HandleSuccess(rsp)
			} else {
				err, ok := errInt.Interface().(error)
				if ok {
					ctx.HandleError(rawCtx.Request.RequestURI, err)
				} else {
					ctx.HandleError(rawCtx.Request.RequestURI, fmt.Errorf("handle request ret error, but parse return error:%+v not ok", err))
				}
			}
		})
	}
	return list
}

func parseRequest(rawCtx *gin.Context, params any) error {
	bodyBuf, err := io.ReadAll(rawCtx.Request.Body)
	if err != nil {
		return fmt.Errorf("read body error:%v", err)
	}

	if len(bodyBuf) == 0 {
		newRequestValue := reflect.ValueOf(params).Elem()
		newRequestValueType := newRequestValue.Type()
		for i := 0; i < newRequestValue.NumField(); i++ {
			f := newRequestValueType.Field(i)
			fieldTagName := f.Tag.Get("json")
			if fieldTagName == "" {
				fieldTagName = f.Name
			}

			field := newRequestValue.Field(i)
			if !field.CanSet() {
				continue
			}
			fieldStr := rawCtx.Query(fieldTagName)
			err := setValue(field, fieldStr, f.Tag.Get("default"), f.Tag.Get("required"))
			if err != nil {
				return fmt.Errorf("parse uri params field(%v) set value(%v) error:%v", f.Name, fieldStr, err)
			}
		}
	} else {
		err = json.Unmarshal(bodyBuf, params)
		if err != nil {
			return fmt.Errorf("json unmarshal body error:%v", err)
		}
	}
	return nil
}

// setValue 设置结构体一个字段的值
func setValue(field reflect.Value, value string, defaultValue string, required string) error {
	if value == "" {
		value = defaultValue
	}
	if value == "" && required == "true" {
		return fmt.Errorf("field is required, please give a valid value")
	}

	if field.Kind() == reflect.Ptr {
		if value == "" {
			return nil
		}

		if field.IsNil() {
			field.Set(reflect.New(field.Type().Elem()))
		}
		field = field.Elem()
	}
	switch field.Kind() {
	case reflect.String:
		field.SetString(value)
	case reflect.Bool:
		if value == "" {
			field.SetBool(false)
		} else {
			b, err := strconv.ParseBool(value)
			if err != nil {
				return err
			}
			field.SetBool(b)
		}
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		if value == "" {
			field.SetInt(0)
		} else {
			i, err := strconv.ParseInt(value, 0, field.Type().Bits())
			if err != nil {
				return err
			}
			field.SetInt(i)
		}
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		if value == "" {
			field.SetUint(0)
			break
		}
		ui, err := strconv.ParseUint(value, 0, field.Type().Bits())
		if err != nil {
			return err
		}
		field.SetUint(ui)
	case reflect.Float32, reflect.Float64:
		if value == "" {
			field.SetFloat(0)
			break
		}
		f, err := strconv.ParseFloat(value, field.Type().Bits())
		if err != nil {
			return err
		}
		field.SetFloat(f)
	case reflect.Struct:
		return fmt.Errorf("unsupport struct field:%v", field.Type())
	case reflect.Slice:
		values := strings.Split(value, ",")
		if len(values) == 1 && values[0] == "" {
			values = []string{}
		}
		field.Set(reflect.MakeSlice(field.Type(), len(values), len(values)))
		for i := 0; i < len(values); i++ {
			err := setValue(field.Index(i), values[i], "", "")
			if err != nil {
				return err
			}
		}

	default:
		return fmt.Errorf("no support type %s", field.Type())
	}
	return nil
}