// Copyright 2020 - 2021 Martin Dosch.
// Use of this source code is governed by the BSD-2-clause
// license that can be found in the LICENSE file.

package main

import (
	"bytes"
	"encoding/xml"
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strconv"

	"github.com/beevik/etree"            // BSD-2-clause
	"github.com/gabriel-vasile/mimetype" // MIT License)
	"github.com/mattn/go-xmpp"           // BSD-3-Clause
)

func httpUpload(client *xmpp.Client, jserver string, filePath string) string {
	var iqDiscoItemsXML IQDiscoItemsType
	var iqDiscoInfoXML IQDiscoInfoType
	var iqHttpUploadSlotXML IQHttpUploadSlot
	var uploadComponent string
	var maxFileSize int64

	// Get file size
	fileInfo, err := os.Stat(filePath)
	if err != nil {
		log.Fatal(err)
	}
	fileSize := fileInfo.Size()

	// Read file
	buffer, err := readFile(filePath)
	if err != nil {
		log.Fatal(err)
	}

	// Get mime type
	mimeType := mimetype.Detect(buffer.Bytes()).String()
	var mimeTypeEscaped bytes.Buffer
	xml.Escape(&mimeTypeEscaped, []byte(mimeType))

	// Get file name
	fileName := filepath.Base(filePath)
	// Just use alphanumerical characters for now to work around
	// https://github.com/mattn/go-xmpp/issues/132
	reg, err := regexp.Compile(`[^a-zA-Z0-9\+\-\_\.]+`)
	if err != nil {
		log.Fatal(err)
	}
	fileNameEscaped := reg.ReplaceAllString(fileName, "_")

	// Query server for disco#items
	iqContent, err := sendIQ(client, jserver, "get",
		"<query xmlns='http://jabber.org/protocol/disco#items'/>")
	if err != nil {
		log.Fatal(err)
	}
	err = xml.Unmarshal(iqContent.Query, &iqDiscoItemsXML)
	if err != nil {
		log.Fatal(err)
	}

	// Check the services reported by disco#items for the http upload service
	for _, r := range iqDiscoItemsXML.Item {
		iqDiscoInfo, err := sendIQ(client, r.Jid, "get",
			"<query xmlns='http://jabber.org/protocol/disco#info'/>")
		if err != nil {
			log.Fatal(err)
		}
		if iqDiscoInfo.Type != "result" {
			continue
		}
		err = xml.Unmarshal(iqDiscoInfo.Query, &iqDiscoInfoXML)
		if err != nil {
			log.Fatal(err)
		}

		if iqDiscoInfoXML.Identity.Type == "file" && iqDiscoInfoXML.Identity.Category == "store" {
			uploadComponent = r.Jid
		}

	}
	if uploadComponent == "" {
		log.Fatal("No http upload component found.")
	}
	for _, r := range iqDiscoInfoXML.X {
		for i, t := range r.Field {
			if t.Var == "max-file-size" && r.Field[i-1].Value == nsHttpUpload {
				maxFileSize, err = strconv.ParseInt(t.Value, 10, 64)
				if err != nil {
					log.Fatal("Error while checking server maximum http upload file size.")
				}
			}
		}
	}
	// Check if the file size doesn't exceed the maximum file size of the http upload
	// component if a maximum file size is reported, if not just continue and hope for
	// the best.
	if maxFileSize != 0 {
		if fileSize > maxFileSize {
			log.Fatal("File size " + strconv.FormatInt(fileSize/1024/1024, 10) +
				" MB is larger than the maximum file size allowed (" +
				strconv.FormatInt(maxFileSize/1024/1024, 10) + " MB).")
		}
	}

	request := etree.NewDocument()
	requestReq := request.CreateElement("request")
	requestReq.CreateAttr("xmlns", nsHttpUpload)
	requestReq.CreateAttr("filename", fileNameEscaped)
	requestReq.CreateAttr("size", fmt.Sprint(fileSize))
	requestReq.CreateAttr("content-type", mimeType)
	r, err := request.WriteToString()
	if err != nil {
		log.Fatal(err)
	}

	// Request http upload slot
	uploadSlot, err := sendIQ(client, uploadComponent, "get", r)
	if err != nil {
		log.Fatal(err)
	}
	if uploadSlot.Type != "result" {
		log.Fatal("Error while requesting upload slot.")
	}
	err = xml.Unmarshal(uploadSlot.Query, &iqHttpUploadSlotXML)
	if err != nil {
		log.Fatal(err)
	}

	// Upload file
	httpClient := &http.Client{}
	req, err := http.NewRequest(http.MethodPut, iqHttpUploadSlotXML.Put.URL, buffer)
	if err != nil {
		log.Fatal(err)
	}
	req.Header.Set("Content-Type", mimeTypeEscaped.String())
	for _, h := range iqHttpUploadSlotXML.Put.Headers {
		switch h.Name {
		case "Authorization", "Cookie", "Expires":
			req.Header.Set(h.Name, h.Value)
		}
	}
	resp, err := httpClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	// Test for http status code "200 OK" or "201 Created"
	if resp.StatusCode != 200 && resp.StatusCode != 201 {
		log.Fatal("Http upload failed.")
	}

	// Return http link
	return iqHttpUploadSlotXML.Get.URL
}