package http

import (
	"bytes"
	json2 "encoding/json"
	"io"
	"net/http"
	"strconv"
	"strings"

	"git.ikuban.com/server/kratos-utils/v2/codes"

	"git.ikuban.com/server/kratos-utils/v2/transport/http/reply"

	"github.com/go-kratos/kratos/v2/errors"

	"github.com/go-kratos/kratos/v2/encoding"
	"google.golang.org/protobuf/types/known/emptypb"

	"git.ikuban.com/server/kratos-utils/v2/transport/http/binding"
	"git.ikuban.com/server/kratos-utils/v2/transport/http/encoding/json"
	_ "github.com/go-kratos/kratos/v2/encoding/proto"
)

// DecodeRequest  decodeRequest decodes the request body to object.
func DecodeRequest(req *http.Request, v interface{}) error {
	if v == nil {
		return nil
	}
	method := strings.ToUpper(req.Method)
	if method == "POST" || method == "PUT" || method == "DELETE" {
		contextType := req.Header.Get(ContentTypeHeader)
		if strings.HasPrefix(contextType, "multipart/form-data") {
			return parseForm(req, v)
		}
		if _, ok := v.(*emptypb.Empty); ok {
			return binding.BindForm(req, v)
		}
		subtype := contentSubtype(contextType)
		if codec := encoding.GetCodec(subtype); codec != nil {
			data, err := io.ReadAll(req.Body)
			if err != nil {
				return err
			}
			return codec.Unmarshal(data, v)
		}
	}
	return binding.BindForm(req, v)
}

func parseForm(req *http.Request, v interface{}) error {
	err := req.ParseMultipartForm(32 << 20)
	if err != nil {
		return err
	}
	if req.MultipartForm == nil {
		return nil
	}
	value := make(map[string]interface{})
	if req.MultipartForm.File != nil {
		for k1, v1 := range req.MultipartForm.File {
			f, err := v1[0].Open()
			if err != nil {
				return err
			}
			var buf bytes.Buffer
			_, err = buf.ReadFrom(f)
			if err != nil {
				return err
			}
			value[k1] = buf.Bytes()
			value[k1+"Filename"] = v1[0].Filename
		}
	}
	if req.MultipartForm.Value != nil {
		for k1, v1 := range req.MultipartForm.Value {
			value[k1] = v1[0]
		}
	}
	j, err := json2.Marshal(value)
	if err != nil {
		return err
	}
	err = json2.Unmarshal(j, v)
	return err
}

// EncodeResponse encodes the object to the HTTP response.
func EncodeResponse(w http.ResponseWriter, r *http.Request, v interface{}) error {
	if v == nil {
		return nil
	}
	codec := codecForRequest(r)
	data, err := codec.Marshal(v)
	if err != nil {
		return err
	}
	w.Header().Set(ContentTypeHeader, contentType(codec.Name()))
	_, _ = w.Write(data)
	return nil
}

func ErrHandle(w http.ResponseWriter, r *http.Request, err error) {
	if err == nil {
		return
	}
	st := errors.FromError(err)
	if st == nil {
		st = codes.Error(10500, err.Error()).(*errors.Error)
	}
	message := st.Message
	metadata := st.GetMetadata()
	code := st.Code
	if _, ok := metadata["code"]; ok {
		_code, _ := strconv.Atoi(metadata["code"])
		code = int32(_code)
	}
	if code == 1000 {
		return
	}
	w.Header().Set(ContentTypeHeader, "application/json; charset=utf-8")
	if code == 0 {
		w.WriteHeader(200)
	} else if code >= 301 && code <= 307 {
		w.WriteHeader(int(code))
		http.Redirect(w, r, message, int(code))
		return
	} else if code == 401 {
		w.WriteHeader(401)
		code = 10401
	} else {
		if code < 10000 {
			code = 10000 + code
		}
		if code < 10100 && message == "" {
			message = "系统错误"
		}
		w.WriteHeader(400)
	}
	_reply := reply.SuccessReply{
		Code:    code,
		Message: message,
		Data:    nil,
	}
	if st.Reason != "" {
		var _data interface{}
		json2.Unmarshal([]byte(st.Reason), &_data)
		_reply.Data = _data
	}
	data, err := json2.Marshal(_reply)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Write(data)
}

const baseContentType = "application"

var (
	acceptHeader      = http.CanonicalHeaderKey("Accept")
	ContentTypeHeader = http.CanonicalHeaderKey("Content-Type")
)

func contentType(subtype string) string {
	return strings.Join([]string{baseContentType, subtype}, "/")
}

// codecForRequest get encoding.Codec via http.Request
func codecForRequest(r *http.Request) encoding.Codec {
	var codec encoding.Codec
	for _, accept := range r.Header[acceptHeader] {
		codeName := contentSubtype(accept)
		if codeName == "json" {
			codec = encoding.GetCodec(json.Name)
			break
		}
		if codec = encoding.GetCodec(codeName); codec != nil {
			break
		}
	}
	if codec == nil {
		codec = encoding.GetCodec(json.Name)
	}
	return codec
}

func contentSubtype(contentType string) string {
	if contentType == baseContentType {
		return ""
	}
	if !strings.HasPrefix(contentType, baseContentType) {
		return ""
	}
	switch contentType[len(baseContentType)] {
	case '/', ';':
		if i := strings.Index(contentType, ";"); i != -1 {
			return contentType[len(baseContentType)+1 : i]
		}
		return contentType[len(baseContentType)+1:]
	default:
		return ""
	}
}

func GetBody(r *http.Request) []byte {
	b, _ := io.ReadAll(r.Body)
	return b
}