package main

import (
	"bufio"
	"crypto/subtle"
	"encoding/json"
	"fmt"
	"html/template"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"

	"github.com/blevesearch/bleve"
	"github.com/blevesearch/bleve/search/highlight/highlighter/html"
	"github.com/gorilla/mux"
	"github.com/mandolyte/mdtopdf"
	"gopkg.in/src-d/go-git.v4"
	"gopkg.in/src-d/go-git.v4/plumbing/object"
)

var config = readConfig("")

type Configuration struct {
	Host        string
	Port        string
	DataPath    string
	DataPathFTS string
	WebUser     string
	WebPasswd   string
}

// our main function
func main() {

	// Ausgeben der Config-Optionen
	fmt.Println("Host: " + config.Host)
	fmt.Println("Post: " + config.Port)
	fmt.Println("DataPath: " + config.DataPath)
	fmt.Println("DataPathFTS: " + config.DataPathFTS)

	// DataPath-Verzeichnis anlegen, wenn es noch nicht existiert
	if !directoryExists(config.DataPath) {
		os.MkdirAll(config.DataPath, os.ModePerm)

		// Default Seiten anlegen
		bStartmd, _ := Asset("web/pages/start.md")
		bHilfemd, _ := Asset("web/pages/hilfe.md")
		bPlaygroundmd, _ := Asset("web/pages/playground.md")
		bSidebarmd, _ := Asset("web/pages/sidebar.md")

		err := ioutil.WriteFile(path.Join(config.DataPath, "start.md"), bStartmd, 0644)
		check(err)
		err = ioutil.WriteFile(path.Join(config.DataPath, "sidebar.md"), bSidebarmd, 0644)
		check(err)
		err = ioutil.WriteFile(path.Join(config.DataPath, "hilfe.md"), bHilfemd, 0644)
		check(err)
		err = ioutil.WriteFile(path.Join(config.DataPath, "playground.md"), bPlaygroundmd, 0644)
		check(err)
	}

	// Git Repository Init
	if !directoryExists(path.Join(config.DataPath, ".git")) {

		_, err := git.PlainInit(config.DataPath, false)
		check(err)
		GitCommit("Initial Wiki Commit")
	}

	// Volltextsuche
	if config.DataPathFTS != "" {
		if strings.HasPrefix(config.DataPathFTS, config.DataPath) {
			fmt.Println("FTS disabled (Please don´t put the DataPathFTS inside the DataPath)")
		} else {
			fmt.Println("FTS enabled")
			if !directoryExists(config.DataPathFTS) {
				fmt.Println("Create new FTS Data in " + config.DataPathFTS)
				mapping := bleve.NewIndexMapping()

				index, err := bleve.New(config.DataPathFTS, mapping)
				check(err)

				filepath.Walk(config.DataPath, func(filepath string, info os.FileInfo, err error) error {
					tmpPath := strings.Replace(filepath, "\\", "/", -1)
					tmpPath = strings.Replace(tmpPath, "data/", "", -1)

					if !info.IsDir() && !strings.HasPrefix(tmpPath, ".git") {
						b, err := ioutil.ReadFile(path.Join(config.DataPath, tmpPath))
						check(err)

						indexData := struct {
							Text string
						}{
							string(b),
						}

						err = index.Index(tmpPath, indexData)
						check(err)
						fmt.Println("Indexed: " + info.Name())
					}
					return nil
				})

				index.Close()
			}
		}
	}

	/*
		repo, err := git.PlainOpen(config.DataPath)
		check(err)

		ref, err := repo.Head()
		check(err)

		// ... retrieves the commit history
		//since := time.Date(2019, 1, 1, 0, 0, 0, 0, time.UTC)
		//until := time.Date(2019, 7, 30, 0, 0, 0, 0, time.UTC)
		var filename = "playground.md"
		cIter, err := repo.Log(&git.LogOptions{From: ref.Hash(), FileName: &filename}) //, Since: &since, Until: &until})
		check(err)

		// ... just iterates over the commits, printing it
		err = cIter.ForEach(func(c *object.Commit) error {
			fmt.Println(c.Files())
			fmt.Println(c.Committer.When)

			return nil
		})
	*/

	router := mux.NewRouter()
	router.HandleFunc("/_api/md/{pagename:.*}", basicAuth(getRawPage)).Methods("GET")
	router.HandleFunc("/_api/pdf/{pagename:.*}", basicAuth(getPDFPage)).Methods("GET")
	router.HandleFunc("/_api/pinfo/{pagename:.*}", basicAuth(getPageInfo)).Methods("GET")
	router.HandleFunc("/_api/fts/{searchterm:.*}", basicAuth(getFTS)).Methods("GET")
	router.HandleFunc("/_api/config", basicAuth(getWikiConfig)).Methods("GET")
	router.HandleFunc("/{pagename:.*}", basicAuth(getHTMLPage)).Methods("GET")
	router.HandleFunc("/{pagename:.*}", basicAuth(postHTMLPage)).Methods("POST")

	log.Fatal(http.ListenAndServe(":"+config.Port, router))

}

func getPDFPage(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pPageName := params["pagename"] + ".md"
	// Hack für anzeige der start.md wenn / aufgerufen wird
	if pPageName == ".md" {
		pPageName = "start.md"
	}

	content, err := ioutil.ReadFile(path.Join(config.DataPath, pPageName))
	check(err)
	pdfRender := mdtopdf.NewPdfRenderer("", "", "./tmp.pdf", "")
	// get the unicode translator
	tr := pdfRender.Pdf.UnicodeTranslatorFromDescriptor("cp1252")

	pdfRender.Normal = mdtopdf.Styler{Font: "Arial", Style: "",
		Size: 8, Spacing: 1,
		TextColor: mdtopdf.Color{0, 0, 0},
		FillColor: mdtopdf.Color{255, 255, 255}}

	err = pdfRender.Process([]byte(tr(string(content))))
	check(err)

	pdfcontent, err := ioutil.ReadFile("./tmp.pdf")
	check(err)
	w.Header().Set("Content-Type", "application/pdf")
	w.Write(pdfcontent)
}

func getHTMLPage(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)

	if strings.HasSuffix(params["pagename"], ".css") {
		//fmt.Println("CSS: " + params["pagename"])
		b, _ := Asset("web/" + params["pagename"])
		w.Header().Set("Content-Type", "text/css")
		w.Write(b)
	} else if strings.HasSuffix(params["pagename"], ".js") {
		//fmt.Println("JS: " + params["pagename"])
		b, _ := Asset("web/" + params["pagename"])
		w.Header().Set("Content-Type", "application/javascript")
		w.Write(b)
	} else {
		// Directory Listing für die Sidebar
		sidebarAusgabe := "  \r\n  \r\n**Inhaltsverzeichnis**  \r\n\r\n"
		filepath.Walk(config.DataPath, func(path string, info os.FileInfo, err error) error {

			tmpPath := strings.Replace(path, "\\", "/", -1)
			tmpPath = strings.Replace(tmpPath, "data", "", -1)
			tmpPathSplit := strings.Split(tmpPath, "/")

			sidebarTABs := ""
			for i, _ := range tmpPathSplit {
				//fmt.Println(i, " => ", string(c))
				if i > 1 {
					sidebarTABs = sidebarTABs + "	"
				}
			}

			if info.Name() != "data" && !strings.HasPrefix(tmpPath, "/.git") && info.Name() != "start.md" && info.Name() != "sidebar.md" && info.Name() != "hilfe.md" {
				if !strings.HasSuffix(info.Name(), ".md") {
					sidebarAusgabe = sidebarAusgabe + sidebarTABs + "* [" + strings.TrimSuffix(info.Name(), ".md") + "](" + strings.TrimSuffix(tmpPath, ".md") + "/start)  \r\n"
				} else {
					sidebarAusgabe = sidebarAusgabe + sidebarTABs + "* [" + strings.TrimSuffix(info.Name(), ".md") + "](" + strings.TrimSuffix(tmpPath, ".md") + ")  \r\n"
				}
			}

			return nil
		})

		//tmpl := template.Must(template.ParseFiles("./web/index.html"))
		bTmpl, _ := Asset("web/index.html")
		tmpl := template.Must(template.New("tml").Parse(string(bTmpl)))
		data := MarkDownData{
			PageTitle: " ",
			MDText:    "",
			SideBar:   sidebarAusgabe,
		}
		tmpl.Execute(w, data)
	}
}

func getRawPage(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pPageName := params["pagename"] + ".md"
	// Hack für anzeige der start.md wenn / aufgerufen wird
	if pPageName == ".md" {
		pPageName = "start.md"
	}
	pageContent := "Empty"

	//fmt.Println(path.Join(config.DataPath, pPageName))
	b, err := ioutil.ReadFile(path.Join(config.DataPath, pPageName))
	check(err)

	pageContent = string(b)

	json.NewEncoder(w).Encode(pageContent)
}

func postHTMLPage(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pPageName := params["pagename"] + ".md"
	// Hack für anzeige der start.md wenn / aufgerufen wird
	if pPageName == ".md" {
		pPageName = "start.md"
	}

	// Verzeichnis erstellen
	dir := path.Dir(pPageName)
	if !directoryExists(path.Join(config.DataPath, dir)) {
		os.MkdirAll(path.Join(config.DataPath, dir), os.ModePerm)
	}

	//{ "MDText":"**test3**" }
	var oBody TPostBody
	json.NewDecoder(r.Body).Decode(&oBody)
	//fmt.Println(oBody)

	f, err := os.Create(path.Join(config.DataPath, pPageName))
	check(err)
	defer f.Close()
	fw := bufio.NewWriter(f)
	_, err = fw.WriteString(oBody.MDText)
	check(err)
	fw.Flush()

	// Git Commit
	GitCommit("Auto-Commit Page: " + pPageName)
	// FTS Index
	BleveIndex(pPageName)

	json.NewEncoder(w).Encode("OK")

}

func getFTS(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pSearchterm := params["searchterm"]

	if config.DataPathFTS != "" {
		if directoryExists(config.DataPathFTS) {

			index, err := bleve.Open(config.DataPathFTS)
			check(err)

			query := bleve.NewQueryStringQuery(pSearchterm)
			search := bleve.NewSearchRequest(query)
			search.Highlight = bleve.NewHighlightWithStyle(html.Name)
			search.Size = 30
			searchResults, err := index.Search(search)
			index.Close()

			//fmt.Println("SR: " + searchResults.String())
			json.NewEncoder(w).Encode(searchResults.Hits)
		}
	}
}

func getPageInfo(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pPageName := params["pagename"] + ".md"

	// Hack für anzeige der start.md wenn / aufgerufen wird
	if pPageName == ".md" {
		pPageName = "start.md"
	}

	f, err := os.Open(path.Join(config.DataPath, pPageName))
	check(err)
	statinfo, err := f.Stat()
	check(err)

	data := struct {
		PageName string
		ModTime  time.Time
	}{
		pPageName,
		statinfo.ModTime(),
	}

	json.NewEncoder(w).Encode(data)
}

func getWikiConfig(w http.ResponseWriter, r *http.Request) {

	FTS := false
	Login := false

	if config.DataPathFTS != "" {
		FTS = true
	}
	if config.WebUser != "" && config.WebPasswd != "" {
		Login = true
	}

	data := struct {
		FTS   bool
		Login bool
	}{
		FTS,
		Login,
	}

	json.NewEncoder(w).Encode(data)
}

func basicAuth(handler http.HandlerFunc) http.HandlerFunc {

	return func(w http.ResponseWriter, r *http.Request) {
		if config.WebUser == "" && config.WebPasswd == "" {
			handler(w, r)
			return
		}

		user, pass, ok := r.BasicAuth()

		if !ok || subtle.ConstantTimeCompare([]byte(user), []byte(config.WebUser)) != 1 || subtle.ConstantTimeCompare([]byte(pass), []byte(config.WebPasswd)) != 1 {
			w.Header().Set("WWW-Authenticate", `Basic realm="Login GoWiki"`)
			w.WriteHeader(401)
			w.Write([]byte("Unauthorised.\n"))
			return
		}

		handler(w, r)
	}
}

//--------------------------------------------------------------------------
// Typen
//--------------------------------------------------------------------------

type MarkDownData struct {
	PageTitle string
	MDText    string
	SideBar   string
}

type TPostBody struct {
	MDText string
}

//--------------------------------------------------------------------------
// Hilfsfunktionen
//--------------------------------------------------------------------------

func check(e error) {
	if e != nil {
		fmt.Println(e)
	}
}

func fileExists(filename string) bool {
	info, err := os.Stat(filename)
	if os.IsNotExist(err) {
		return false
	}
	return !info.IsDir()
}

func directoryExists(filename string) bool {
	info, err := os.Stat(filename)
	if os.IsNotExist(err) {
		return false
	}
	return info.IsDir()
}

func readConfig(filename string) *Configuration {
	// initialize conf with default values.
	conf := &Configuration{Host: "http://127.0.0.1", Port: "8000", DataPath: "./data", DataPathFTS: "", WebUser: "", WebPasswd: ""}

	b, err := ioutil.ReadFile("./config.json")
	if err != nil {
		return conf
	}
	if err = json.Unmarshal(b, conf); err != nil {
		return conf
	}
	return conf
}

func GitCommit(CommitText string) {

	// Git Repo öffnen
	repo, err := git.PlainOpen(config.DataPath)
	check(err)

	// Working Tree setzen
	wt, err := repo.Worktree()
	check(err)

	// Alle Dateien zum Working Tree hinzufügen
	_, err = wt.Add(".")
	check(err)

	// Status ausgeben
	//status, err := wt.Status()
	//check(err)
	//fmt.Println(status)

	// Neuen Commit Erstellen
	_, err = wt.Commit(CommitText, &git.CommitOptions{
		Author: &object.Signature{
			Name:  "GoWiki",
			Email: "gowiki@local.org",
			When:  time.Now(),
		},
	})
	check(err)

	// Commit infos anzeigen
	//obj, err := repo.CommitObject(commit)
	//check(err)
	//fmt.Println(obj)
}

func BleveIndex(PageName string) {
	if config.DataPathFTS != "" {
		if directoryExists(config.DataPathFTS) {

			index, err := bleve.Open(config.DataPathFTS)
			check(err)

			b, err := ioutil.ReadFile(path.Join(config.DataPath, PageName))
			check(err)

			indexData := struct {
				Text string
			}{
				string(b),
			}
			err = index.Index(PageName, indexData)
			check(err)
			index.Close()
		}
	}
}