package gateway

import (
	"bytes"
	"errors"
	"io/ioutil"
	"mime/multipart"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/smallnest/rpcx/protocol"
)

const (
	XVersion           = "X-RPCX-Version"
	XMessageType       = "X-RPCX-MesssageType"
	XHeartbeat         = "X-RPCX-Heartbeat"
	XOneway            = "X-RPCX-Oneway"
	XMessageStatusType = "X-RPCX-MessageStatusType"
	XSerializeType     = "X-RPCX-SerializeType"
	XMessageID         = "X-RPCX-MessageID"
	XServicePath       = "X-RPCX-ServicePath"
	XServiceMethod     = "X-RPCX-ServiceMethod"
	XMeta              = "X-RPCX-Meta"
	XErrorMessage      = "X-RPCX-ErrorMessage"
)

func HttpRequest2RpcxRequest(r *http.Request) (*protocol.Message, error) {
	req := protocol.NewMessage()
	req.SetMessageType(protocol.Request)

	h := r.Header
	seq := getRpcxHeader(r, XMessageID)
	if seq != "" {
		id, err := strconv.ParseUint(seq, 10, 64)
		if err != nil {
			return nil, err
		}
		req.SetSeq(id)
	}

	heartbeat := getRpcxHeader(r, XHeartbeat)
	if heartbeat != "" {
		req.SetHeartbeat(true)
	}

	oneway := getRpcxHeader(r, XOneway)
	if oneway != "" {
		req.SetOneway(true)
	}

	if h.Get("Content-Encoding") == "gzip" {
		req.SetCompressType(protocol.Gzip)
	}

	st := getRpcxHeader(r, XSerializeType)
	if st != "" {
		rst, err := strconv.Atoi(st)
		if err != nil {
			return nil, err
		}
		req.SetSerializeType(protocol.SerializeType(rst))
	} else {
		return nil, errors.New("empty serialized type")
	}

	meta := getRpcxHeader(r, XMeta)
	if meta != "" {
		metadata, err := url.ParseQuery(meta)
		if err != nil {
			return nil, err
		}
		mm := make(map[string]string)
		for k, v := range metadata {
			if len(v) > 0 {
				mm[k] = v[0]
			}
		}
		req.Metadata = mm
	}

	req.Metadata = getUrlParams(r, req.Metadata)

	sp := getRpcxHeader(r, XServicePath)
	if sp != "" {
		req.ServicePath = sp
	} else {
		return nil, errors.New("empty servicepath")
	}

	sm := getRpcxHeader(r, XServiceMethod)
	if sm != "" {
		req.ServiceMethod = sm
	} else {
		return nil, errors.New("empty servicemethod")
	}

	payload, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return nil, err
	}

	req.Payload = payload
	// Request.Body的读取, 读取数据时, 指针会对应移动至EOF, 所以下次读取的时候, seek指针还在EOF处
	// 后续无法获取请求数据，在此读完又存
	r.Body = ioutil.NopCloser(bytes.NewBuffer(payload))
	return req, nil
}

func MultipartRequest2RpcxRequest(r *http.Request) (map[string]string, map[string][]*multipart.FileHeader, error) {
	r.ParseMultipartForm(10 << 20) //10mb
	form := r.MultipartForm
	formValues := make(map[string]string)
	//获取 multi-part/form header的 value
	h := r.Header
	meta := h.Get(XMeta)
	if meta != "" {
		metadata, err := url.ParseQuery(meta)
		if err != nil {
			return nil, nil, err
		}
		for k, v := range metadata {
			if len(v) > 0 {
				formValues[k] = v[0]
			}
		}
	}

	//获取 multi-part/form body中的form value
	for k, v := range form.Value {
		formValues[k] = v[0]
	}

	sp := h.Get(XServicePath)
	if sp != "" {
		formValues["reqService"] = sp
	} else {
		return nil, nil, errors.New("empty servicepath")
	}

	sm := h.Get(XServiceMethod)
	if sm != "" {
		formValues["reqMethod"] = sm
	} else {
		return nil, nil, errors.New("empty servicemethod")
	}
	formValues["authExclude"] = "false"

	formValues["fileNum"] = strconv.Itoa(len(form.File))

	return formValues, form.File, nil
}

func getRpcxHeader(r *http.Request, key string) string {
	val := r.Header.Get(key)
	if val != "" {
		return val
	} else {
		if values, ok := r.URL.Query()[key]; ok && len(values) > 0 {
			return values[0]
		} else {
			return ""
		}
	}
}

func getUrlParams(r *http.Request, metadata map[string]string) map[string]string {
	if len(metadata) == 0 {
		metadata = make(map[string]string)
	}
	query := r.URL.Query()
	for k, v := range query {
		if !strings.HasPrefix(k, "X-RPCX-") && len(v) > 0 {
			metadata[k] = v[0]
		}
	}
	return metadata
}

// func RpcxResponse2HttpResponse(res *protocol.Message) (url.Values, []byte, error) {
// 	m := make(url.Values)
// 	m.Set(XVersion, strconv.Itoa(int(res.Version())))
// 	if res.IsHeartbeat() {
// 		m.Set(XHeartbeat, "true")
// 	}
// 	if res.IsOneway() {
// 		m.Set(XOneway, "true")
// 	}
// 	if res.MessageStatusType() == protocol.Error {
// 		m.Set(XMessageStatusType, "Error")
// 	} else {
// 		m.Set(XMessageStatusType, "Normal")
// 	}

// 	if res.CompressType() == protocol.Gzip {
// 		m.Set("Content-Encoding", "gzip")
// 	}

// 	m.Set(XSerializeType, strconv.Itoa(int(res.SerializeType())))
// 	m.Set(XMessageID, strconv.FormatUint(res.Seq(), 10))
// 	m.Set(XServicePath, res.ServicePath)
// 	m.Set(XServiceMethod, res.ServiceMethod)

// 	return m, res.Payload, nil
// }