package office

import (
	ole "github.com/go-ole/go-ole"
	"github.com/go-ole/go-ole/oleutil"
	log "github.com/sirupsen/logrus"
)

/// 更多內(nèi)容請參考官方COM文檔 https://docs.microsoft.com/zh-cn/office/vba/api/word.application
type Operation struct {
	OpType    string
	Arguments []interface{}
}

/// 部分應(yīng)用不允許隱藏 ，比如ppt，所以Visible需要設(shè)定下
type ConvertHandler struct {
	FileInPath      string
	FileOutPath     string
	ApplicationName string
	WorkspaceName   string
	Visible         bool
	DisplayAlerts   int
	OpenFileOp      Operation
	ExportOp        Operation
	CloseOp         Operation
	QuitOp          Operation
}

type DomConvertObject struct {
	Application *ole.IDispatch
	Workspace   *ole.IDispatch
	SingleFile  *ole.IDispatch
}

func (handler ConvertHandler) Convert() {
	ole.CoInitialize(0)
	defer ole.CoUninitialize()

	log.Println("handle open start")
	dom := handler.Open()
	log.Println("handle open end")
	log.Println("handler in file path is " + handler.FileInPath)
	log.Println("handler out file path is " + handler.FileOutPath)

	defer dom.Application.Release()
	defer dom.Workspace.Release()
	defer dom.SingleFile.Release()

	handler.Export(dom)
	log.Println("handle export end")

	handler.Close(dom)
	log.Println("handle close end")

	handler.Quit(dom)
	log.Println("handle quit end")

}
func (handler ConvertHandler) Open() DomConvertObject {
	var dom DomConvertObject
	unknown, err := oleutil.CreateObject(handler.ApplicationName)
	if err != nil {
		panic(err)
	}
	dom.Application = unknown.MustQueryInterface(ole.IID_IDispatch)

	oleutil.MustPutProperty(dom.Application, "Visible", handler.Visible)
	oleutil.MustPutProperty(dom.Application, "DisplayAlerts", handler.DisplayAlerts)

	dom.Workspace = oleutil.MustGetProperty(dom.Application, handler.WorkspaceName).ToIDispatch()

	dom.SingleFile = oleutil.MustCallMethod(dom.Workspace, handler.OpenFileOp.OpType, handler.OpenFileOp.Arguments...).ToIDispatch()
	return dom
}

func (handler ConvertHandler) Export(dom DomConvertObject) {
	oleutil.MustCallMethod(dom.SingleFile, handler.ExportOp.OpType, handler.ExportOp.Arguments...)

}

func (handler ConvertHandler) Close(dom DomConvertObject) {
	if handler.ApplicationName == "PowerPoint.Application" {
		oleutil.MustCallMethod(dom.SingleFile, handler.CloseOp.OpType, handler.CloseOp.Arguments...)
	} else {
		oleutil.MustCallMethod(dom.Workspace, handler.CloseOp.OpType, handler.CloseOp.Arguments...)
	}
}

func (handler ConvertHandler) Quit(dom DomConvertObject) {
	oleutil.MustCallMethod(dom.Application, handler.QuitOp.OpType, handler.QuitOp.Arguments...)

package office

func ConvertDoc2Pdf(fileInputPath string, fileOutputPath string) {

	openArgs := []interface{}{fileInputPath}

	/// https://docs.microsoft.com/zh-cn/office/vba/api/word.document.exportasfixedformat
	exportArgs := []interface{}{fileOutputPath, 17}

	closeArgs := []interface{}{}

	quitArgs := []interface{}{}

	convertHandler := ConvertHandler{
		FileInPath:      fileInputPath,
		FileOutPath:     fileOutputPath,
		ApplicationName: "Word.Application",
		WorkspaceName:   "Documents",
		Visible:         false,
		DisplayAlerts:   0,
		OpenFileOp: Operation{
			OpType:    "Open",
			Arguments: openArgs,
		},
		ExportOp: Operation{
			OpType:    "ExportAsFixedFormat",
			Arguments: exportArgs,
		},
		CloseOp: Operation{

			OpType:    "Close",
			Arguments: closeArgs,
		},
		QuitOp: Operation{

			OpType:    "Quit",
			Arguments: quitArgs,
		},
	}
	convertHandler.Convert()
}

package web

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"office-convert/office"
	"os"
	"path"
	"path/filepath"
	"runtime/debug"
	"strconv"

	log "github.com/sirupsen/logrus"
)

const PORT = 10000
const SAVED_DIR = "files"

type ConvertRequestInfo struct {
	FileInUrl  string `json:"file_in_url"`
	SourceType string `json:"source_type"`
	TargetType string `json:"target_type"`
}

func logStackTrace(err ...interface{}) {
	log.Println(err)
	stack := string(debug.Stack())
	log.Println(stack)
}

func convertHandler(w http.ResponseWriter, r *http.Request) {
	defer func() {
		if r := recover(); r != nil {
			w.WriteHeader(503)
			fmt.Fprintln(w, r)
			logStackTrace(r)
		}
	}()
	if r.Method != "POST" {
		w.WriteHeader(400)
		fmt.Fprintf(w, "Method not support")
		return
	}

	var convertRequestInfo ConvertRequestInfo
	reqBody, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Println(err)
	}
	json.Unmarshal(reqBody, &convertRequestInfo)

	log.Println(convertRequestInfo)
	log.Println(convertRequestInfo.FileInUrl)

	downloadFile(convertRequestInfo.FileInUrl)

	fileOutAbsPath := getFileOutAbsPath(convertRequestInfo.FileInUrl, convertRequestInfo.TargetType)
	convert(convertRequestInfo)

	w.WriteHeader(http.StatusOK)
	w.Header().Set("Content-Type", "application/octet-stream")
	//文件過大的話考慮使用io.Copy進行流式拷貝
	outFileBytes, err := ioutil.ReadFile(fileOutAbsPath)
	if err != nil {
		panic(err)
	}
	w.Write(outFileBytes)

}

func convert(convertRequestInfo ConvertRequestInfo) {

	fileOutAbsPath := getFileOutAbsPath(convertRequestInfo.FileInUrl, convertRequestInfo.TargetType)
	switch convertRequestInfo.SourceType {
	case "doc", "docx":
		office.ConvertDoc2Pdf(getFileInAbsPath(convertRequestInfo.FileInUrl), fileOutAbsPath)
		break
	case "xls", "xlsx":
		office.ConvertXsl2Pdf(getFileInAbsPath(convertRequestInfo.FileInUrl), fileOutAbsPath)
		break
	case "ppt", "pptx":
		office.ConvertPPT2Pdf(getFileInAbsPath(convertRequestInfo.FileInUrl), fileOutAbsPath)
		break
	}
}

func getNameFromUrl(inputUrl string) string {
	u, err := url.Parse(inputUrl)
	if err != nil {
		panic(err)
	}
	return path.Base(u.Path)
}

func getCurrentWorkDirectory() string {
	cwd, err := os.Getwd()
	if err != nil {
		panic(err)
	}
	return cwd
}

func getFileInAbsPath(url string) string {
	fileName := getNameFromUrl(url)
	currentWorkDirectory := getCurrentWorkDirectory()
	absPath := filepath.Join(currentWorkDirectory, SAVED_DIR, fileName)
	return absPath
}

func getFileOutAbsPath(fileInUrl string, targetType string) string {
	return getFileInAbsPath(fileInUrl) + "." + targetType
}

func downloadFile(url string) {
	log.Println("Start download file url :", url)
	resp, err := http.Get(url)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	fileInAbsPath := getFileInAbsPath(url)
	dir := filepath.Dir(fileInAbsPath)
	// log.Println("dir is " + dir)
	if _, err := os.Stat(dir); os.IsNotExist(err) {
		log.Println("dir is not exists")
		os.MkdirAll(dir, 0644)
	}
	out, err := os.Create(fileInAbsPath)
	log.Println("save file to " + fileInAbsPath)
	if err != nil {
		panic(err)
	}

	defer out.Close()

	_, err = io.Copy(out, resp.Body)
	if err != nil {
		panic(err)
	}

	log.Println("Download file end url :", url)
}

func StartServer() {

	log.Println("start service ...")
	http.HandleFunc("/convert", convertHandler)
	http.ListenAndServe("127.0.0.1:"+strconv.Itoa(PORT), nil)
}

server {
        listen       80;
        server_name  convert-tools.xxx.net;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
            proxy_pass http://127.0.0.1:10000;
        }
        # ...其他設(shè)置
}

{
    "file_in_url":"https://your_docx_file_url",
    "source_type":"docx",
    "target_type":"pdf"
}