package utils

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"git.nutfactory.org/hoernschen/Matrix/config"
)

type RequestSummary struct {
	Method      string                       `json:"method,omitempty"`
	Uri         string                       `json:"uri,omitempty"`
	Origin      string                       `json:"origin,omitempty"`
	Destination string                       `json:"destination,omitempty"`
	Content     string                       `json:"content,omitempty"`
	Signatures  map[string]map[string]string `json:"signatures,omitempty"`
}

type ErrorResponse struct {
	ErrorCode    string `json:"errcode,omitempty"`
	ErrorMessage string `json:"error,omitempty"`
	RetryTime    int    `json:"retry_after_ms,omitempty"`
}

func CheckRequest(r *http.Request) (response *ErrorResponse) {
	if !strings.Contains(r.Header.Get("Content-Type"), "application/json") {
		response = &ErrorResponse{ErrorMessage: "Content Type not JSON"}
	}
	return
}

func CheckAuthHeader(r *http.Request) (response *ErrorResponse) {
	authHeader := r.Header.Get("Authorization")
	if authHeader == "" || !strings.Contains(authHeader, "X-Matrix") {
		response = &ErrorResponse{ErrorMessage: "Missing Authorization Header"}
		return
	}
	keys := strings.Split(authHeader, ",")
	origin := strings.Split(keys[0], "=")[1]
	if !strings.Contains(keys[2], "ed25519") {
		response = &ErrorResponse{ErrorMessage: "Missing ed25519 Signature Key"}
		return
	}
	key := strings.Split(strings.Replace(strings.Split(keys[2], "=")[1], "\"", "", 2), ":")[1]
	signature := strings.Replace(strings.Split(keys[2], "=")[1], "\"", "", 2)
	buf := new(bytes.Buffer)
	buf.ReadFrom(r.Body)
	content := buf.String()
	requestSummary := RequestSummary{
		Method:      r.Method,
		Uri:         r.RequestURI,
		Origin:      origin,
		Destination: config.Homeserver,
		Content:     content,
	}
	requestSummaryString, err := json.Marshal(requestSummary)
	if err != nil {
		response = &ErrorResponse{ErrorMessage: "Error Creating Auth JSON String"}
		return
	}
	correct := VerifySignature([]byte(key), requestSummaryString, []byte(signature))
	if !correct {
		response = &ErrorResponse{ErrorMessage: "Signature in Auth Header is incorrect"}
		return
	}
	return
}

func CreateAuthHeader(method string, uri string, destination string, content string) (authHeader string, err error) {
	requestSummary := RequestSummary{
		Method:      method,
		Uri:         uri,
		Origin:      config.Homeserver,
		Destination: destination,
		Content:     content,
	}
	SigningContent, err := json.Marshal(requestSummary)
	if err != nil {
		return
	}
	authHeader = fmt.Sprintf("X-Matrix origin=%s,key=\"%s\",sig=\"%s\"", config.Homeserver, config.KeyId, Sign(SigningContent))
	return
}

func GetAccessToken(r *http.Request) (token string, response *ErrorResponse) {
	token = r.URL.Query().Get("access_token")
	if token == "" {
		token = r.Header.Get("Authorization")
		if token == "" || !strings.Contains(token, "Bearer") {
			response = &ErrorResponse{ErrorCode: "M_MISSING_TOKEN"}
		} else {
			token = strings.Split(token, " ")[1]
		}
	}
	return
}

func IsJSONString(s string) bool {
	var js string
	return json.Unmarshal([]byte(s), &js) == nil

}

func IsJSON(s string) bool {
	var js interface{}
	return json.Unmarshal([]byte(s), &js) == nil

}