package main

import (
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/codegangsta/negroni"
	"github.com/gobuffalo/packr/v2"
	"github.com/gorilla/mux"
	"github.com/jinzhu/gorm"
	"github.com/joho/godotenv"
	"github.com/rs/cors"
	"github.com/rubenv/sql-migrate"
	uuid "github.com/satori/go.uuid"
	ini "gopkg.in/ini.v1"

	"github.com/muety/wakapi/middlewares"
	"github.com/muety/wakapi/models"
	"github.com/muety/wakapi/routes"
	"github.com/muety/wakapi/services"
	"github.com/muety/wakapi/utils"

	_ "github.com/jinzhu/gorm/dialects/mysql"
	_ "github.com/jinzhu/gorm/dialects/postgres"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
)

// TODO: Refactor entire project to be structured after business domains

func readConfig() *models.Config {
	if err := godotenv.Load(); err != nil {
		log.Fatal(err)
	}

	env := utils.LookupFatal("ENV")
	dbType := utils.LookupFatal("WAKAPI_DB_TYPE")
	dbUser := utils.LookupFatal("WAKAPI_DB_USER")
	dbPassword := utils.LookupFatal("WAKAPI_DB_PASSWORD")
	dbHost := utils.LookupFatal("WAKAPI_DB_HOST")
	dbName := utils.LookupFatal("WAKAPI_DB_NAME")
	dbPortStr := utils.LookupFatal("WAKAPI_DB_PORT")
	defaultUserName := utils.LookupFatal("WAKAPI_DEFAULT_USER_NAME")
	defaultUserPassword := utils.LookupFatal("WAKAPI_DEFAULT_USER_PASSWORD")
	dbPort, err := strconv.Atoi(dbPortStr)

	cfg, err := ini.Load("config.ini")
	if err != nil {
		log.Fatalf("Fail to read file: %v", err)
	}

	if dbType == "" {
		dbType = "mysql"
	}

	dbMaxConn := cfg.Section("database").Key("max_connections").MustUint(1)
	addr := cfg.Section("server").Key("listen").MustString("127.0.0.1")
	port, err := strconv.Atoi(os.Getenv("PORT"))
	if err != nil {
		port = cfg.Section("server").Key("port").MustInt()
	}

	cleanUp := cfg.Section("app").Key("cleanup").MustBool(false)

	// Read custom languages
	customLangs := make(map[string]string)
	languageKeys := cfg.Section("languages").Keys()
	for _, k := range languageKeys {
		customLangs[k.Name()] = k.MustString("unknown")
	}

	// Read language colors
	// Source: https://raw.githubusercontent.com/ozh/github-colors/master/colors.json
	var colors = make(map[string]string)
	var rawColors map[string]struct {
		Color string `json:"color"`
		Url   string `json:"url"`
	}

	data, err := ioutil.ReadFile("data/colors.json")
	if err != nil {
		log.Fatal(err)
	}

	if err := json.Unmarshal(data, &rawColors); err != nil {
		log.Fatal(err)
	}

	for k, v := range rawColors {
		colors[strings.ToLower(k)] = v.Color
	}

	return &models.Config{
		Env:                 env,
		Port:                port,
		Addr:                addr,
		DbHost:              dbHost,
		DbPort:              uint(dbPort),
		DbUser:              dbUser,
		DbPassword:          dbPassword,
		DbName:              dbName,
		DbDialect:           dbType,
		DbMaxConn:           dbMaxConn,
		CleanUp:             cleanUp,
		DefaultUserName:     defaultUserName,
		DefaultUserPassword: defaultUserPassword,
		CustomLanguages:     customLangs,
		LanguageColors:      colors,
	}
}

func main() {
	// Read Config
	config := readConfig()
	// Enable line numbers in logging
	if config.IsDev() {
		log.SetFlags(log.LstdFlags | log.Lshortfile)
	}

	// Connect to database
	db, err := gorm.Open(config.DbDialect, utils.MakeConnectionString(config))
	if config.DbDialect == "sqlite3" {
		db.DB().Exec("PRAGMA foreign_keys = ON;")
	}
	db.LogMode(config.IsDev())
	db.DB().SetMaxIdleConns(int(config.DbMaxConn))
	db.DB().SetMaxOpenConns(int(config.DbMaxConn))
	if err != nil {
		log.Println(err)
		log.Fatal("Could not connect to database.")
	}
	// TODO: Graceful shutdown
	defer db.Close()

	// Migrate database schema
	migrateDo := databaseMigrateActions(config.DbDialect)
	migrateDo(db)

	// Custom migrations and initial data
	addDefaultUser(db, config)
	migrateLanguages(db, config)

	// Services
	aliasSrvc := &services.AliasService{Config: config, Db: db}
	heartbeatSrvc := &services.HeartbeatService{Config: config, Db: db}
	userSrvc := &services.UserService{Config: config, Db: db}
	summarySrvc := &services.SummaryService{Config: config, Db: db, HeartbeatService: heartbeatSrvc, AliasService: aliasSrvc}
	aggregationSrvc := &services.AggregationService{Config: config, Db: db, UserService: userSrvc, SummaryService: summarySrvc, HeartbeatService: heartbeatSrvc}

	services := []services.Initializable{aliasSrvc, heartbeatSrvc, summarySrvc, userSrvc, aggregationSrvc}
	for _, s := range services {
		s.Init()
	}

	// Aggregate heartbeats to summaries and persist them
	go aggregationSrvc.Schedule()

	if config.CleanUp {
		go heartbeatSrvc.ScheduleCleanUp()
	}

	// Handlers
	heartbeatHandler := &routes.HeartbeatHandler{HeartbeatSrvc: heartbeatSrvc}
	summaryHandler := &routes.SummaryHandler{SummarySrvc: summarySrvc}
	healthHandler := &routes.HealthHandler{Db: db}

	// Middlewares
	authenticateMiddleware := &middlewares.AuthenticateMiddleware{
		UserSrvc:       userSrvc,
		WhitelistPaths: []string{"/api/health"},
	}
	basicAuthMiddleware := &middlewares.RequireBasicAuthMiddleware{}
	corsMiddleware := cors.New(cors.Options{
		AllowedOrigins: []string{"*"},
		AllowedHeaders: []string{"*"},
		Debug:          false,
	})

	// Setup Routing
	router := mux.NewRouter()
	mainRouter := mux.NewRouter().PathPrefix("/").Subrouter()
	apiRouter := mux.NewRouter().PathPrefix("/api").Subrouter()

	// Main Routes
	mainRouter.Path("/").Methods(http.MethodGet).HandlerFunc(summaryHandler.Index)

	// API Routes
	apiRouter.Path("/heartbeat").Methods(http.MethodPost).HandlerFunc(heartbeatHandler.ApiPost)
	apiRouter.Path("/summary").Methods(http.MethodGet).HandlerFunc(summaryHandler.ApiGet)
	apiRouter.Path("/health").Methods(http.MethodGet).HandlerFunc(healthHandler.ApiGet)

	// Static Routes
	router.PathPrefix("/assets").Handler(negroni.Classic().With(negroni.Wrap(http.FileServer(http.Dir("./static")))))

	// Sub-Routes Setup
	router.PathPrefix("/api").Handler(negroni.Classic().
		With(corsMiddleware).
		With(
			negroni.HandlerFunc(authenticateMiddleware.Handle),
			negroni.Wrap(apiRouter),
		))

	router.PathPrefix("/").Handler(negroni.Classic().With(
		negroni.HandlerFunc(basicAuthMiddleware.Handle),
		negroni.HandlerFunc(authenticateMiddleware.Handle),
		negroni.Wrap(mainRouter),
	))

	// Listen HTTP
	portString := config.Addr + ":" + strconv.Itoa(config.Port)
	s := &http.Server{
		Handler:      router,
		Addr:         portString,
		ReadTimeout:  10 * time.Second,
		WriteTimeout: 10 * time.Second,
	}
	log.Printf("Listening on %+s\n", portString)
	s.ListenAndServe()
}

func databaseMigrateActions(dbDialect string) func(db *gorm.DB) {
	var migrateDo func(db *gorm.DB)
	if dbDialect == "sqlite3" {
		migrations := &migrate.PackrMigrationSource{
			Box: packr.New("migrations", "./migrations/sqlite3"),
		}
		migrateDo = func(db *gorm.DB) {
			n, err := migrate.Exec(db.DB(), "sqlite3", migrations, migrate.Up)
			if err != nil {
				log.Fatal(err)
			}
			log.Printf("Applied %d migrations!\n", n)
		}
	} else {
		migrateDo = func(db *gorm.DB) {
			db.AutoMigrate(&models.Alias{})
			db.AutoMigrate(&models.Summary{})
			db.AutoMigrate(&models.SummaryItem{})
			db.AutoMigrate(&models.User{})
			db.AutoMigrate(&models.Heartbeat{}).AddForeignKey("user_id", "users(id)", "RESTRICT", "RESTRICT")
			db.AutoMigrate(&models.SummaryItem{}).AddForeignKey("summary_id", "summaries(id)", "CASCADE", "CASCADE")
		}
	}
	return migrateDo
}

func migrateLanguages(db *gorm.DB, cfg *models.Config) {
	for k, v := range cfg.CustomLanguages {
		result := db.Model(models.Heartbeat{}).
			Where("language = ?", "").
			Where("entity LIKE ?", "%."+k).
			Updates(models.Heartbeat{Language: v})
		if result.Error != nil {
			log.Fatal(result.Error)
		}
		if result.RowsAffected > 0 {
			log.Printf("Migrated %+v rows for custom language %+s.\n", result.RowsAffected, k)
		}
	}
}

func addDefaultUser(db *gorm.DB, cfg *models.Config) {
	pw := md5.Sum([]byte(cfg.DefaultUserPassword))
	pwString := hex.EncodeToString(pw[:])
	apiKey := uuid.NewV4().String()
	u := &models.User{ID: cfg.DefaultUserName, Password: pwString, ApiKey: apiKey}
	result := db.FirstOrCreate(u, &models.User{ID: u.ID})
	if result.Error != nil {
		log.Println("Unable to create default user.")
		log.Fatal(result.Error)
	}
	if result.RowsAffected > 0 {
		log.Printf("Created default user '%s' with password '%s' and API key '%s'.\n", u.ID, cfg.DefaultUserPassword, u.ApiKey)
	}
}