/*
	Copyright 2021 Arsen Musayelyan

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*/

package main

import (
	"errors"
	"fmt"
	"github.com/Masterminds/sprig"
	"github.com/gorilla/mux"
	"github.com/pelletier/go-toml"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	flag "github.com/spf13/pflag"
	"github.com/wader/gormstore/v2"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
	"html/template"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// Set global logger to ConsoleWriter
var Log = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})

type App struct {
	Route     *mux.Router
	Templates map[string]*template.Template
	Session   *gormstore.Store
	Config    Conf
}

// Create new empty map to store templates
var templates = map[string]*template.Template{}

func main() {
	// Create command-line flags
	addr := flag.IPP("addr", "a", net.ParseIP("0.0.0.0"), "Bind address for HTTP server")
	port := flag.IntP("port", "p", 8080, "Bind port for HTTP server")
	config := flag.StringP("config", "c", "simpledash.toml", "TOML config file")
	hash := flag.String("hash", "", "Generate new bcrypt password hash")
	flag.ErrHelp = errors.New("simpledash: help requested")
	// Parse flags
	flag.Parse()

	if *hash != "" {
		hash, err := bcrypt.GenerateFromPassword([]byte(*hash), bcrypt.DefaultCost)
		if err != nil {
			Log.Fatal().Err(err).Msg("Error creating bcrypt hash")
		}
		fmt.Println(string(hash))
		os.Exit(0)
	}

	// Create new router
	router := mux.NewRouter().StrictSlash(true)

	// Create OS-specific glob for all templates
	path := filepath.Join("resources", "templates", "*.html")
	// Create OS-specific glob for all card templates
	cardGlob := filepath.Join("resources", "templates", "cards", "*.html")
	// Get all template paths
	tmplMatches, _ := filepath.Glob(path)
	cardMatches, _ := filepath.Glob(cardGlob)
	matches := append(tmplMatches, cardMatches...)
	// For each template path
	for _, match := range matches {
		// Get name of file without path or extension
		fileName := strings.TrimSuffix(filepath.Base(match), filepath.Ext(match))
		// If file is called base
		if fileName == "base" {
			// Skip
			continue
		}
		var err error
		// Parse detected template and base template, add to templates map
		templates[fileName], err = template.New(
			filepath.Base(match)).Funcs(
			sprig.FuncMap()).Funcs(
			getFuncMap()).ParseFiles(
			"resources/templates/base.html", match)
		if err != nil {
			Log.Fatal().Str("template", fileName).Err(err).Msg("Error parsing template")
		}
	}

	// Open sqlite database called sessions.db for storing sessions
	sessionDB, _ := gorm.Open(sqlite.Open("sessions.db"), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
	// Create session store from database
	sessionStore := gormstore.New(sessionDB, []byte(""))

	// Create channel to stop periodic cleanup
	quitCleanup := make(chan struct{})
	// Clean up expired sessions every hour
	go sessionStore.PeriodicCleanup(1*time.Hour, quitCleanup)

	// Open config file
	configFile, err := os.Open(filepath.Clean(*config))
	if err != nil {
		Log.Fatal().Err(err).Msg("Error opening config file")
	}
	// Create new TOML decoder
	dec := toml.NewDecoder(configFile)
	// Create new nil variable to store decoded config
	var decodedConf Conf
	// Decode config into variable
	err = dec.Decode(&decodedConf)
	if err != nil {
		Log.Fatal().Err(err).Msg("Error decoding config file")
	}

	// Register HTTP routes
	registerRoutes(App{
		Route:     router,
		Templates: templates,
		Session:   sessionStore,
		Config:    decodedConf,
	})

	// Create string address from flag values
	strAddr := fmt.Sprint(*addr, ":", *port)
	// Create listener on IPv4 using address created above
	ln, err := net.Listen("tcp4", strAddr)
	if err != nil {
		Log.Fatal().Err(err).Msg("Error creating listener")
	}

	// Log HTTP server start
	Log.Info().Str("addr", strAddr).Msg("Starting HTTP server")
	// Start HTTP server using previously-created router and listener
	err = http.Serve(ln, router)
	if err != nil {
		Log.Fatal().Err(err).Msg("Error while serving")
	}
}