package main

import (
	"database/sql"
	"encoding/json"
	"flag"
	"fmt"
	"github.com/gorilla/sessions"
	"github.com/gorilla/csrf"
	_ "github.com/lib/pq"
	"net/http"
	"os"
)

const (
	VERSION      = "0.1"
	MAX_DB_CONNS = 10 // already excessive for personal app
)

type Config struct {
	Sql struct {
		Host     string
		Dbname   string
		Username string
		Password string
	}
	Port string
	Url  string
}

const (
	flash_err  = "_flash_err"
	flash_info = "_flash_info"
)

var (
	config Config
	db     *sql.DB
	store  = sessions.NewCookieStore([]byte("key-store-auth-secret"))
)

func loadConfig(env string) {
	file, err := os.Open("config/" + env + ".json")
	if err != nil {
		fmt.Println("Error: cannot open config file: config/" + env + ".json")
		os.Exit(-1)
	}
	defer file.Close();
	decoder := json.NewDecoder(file)
	err = decoder.Decode(&config)
	if err != nil {
		fmt.Println("Error: cannot decode config file: ", err)
		os.Exit(-1)
	}
}

func dbConnect() {
	var err error
	db, err = sql.Open("postgres", fmt.Sprintf("postgres://%s:%s@%s/%s?sslmode=require", config.Sql.Username, config.Sql.Password, config.Sql.Host, config.Sql.Dbname))

	if err != nil {
		fmt.Println("DB ERROR: ", err)
	}
	db.SetMaxIdleConns(MAX_DB_CONNS)
	err = db.Ping()
	if err != nil {
		fmt.Println("DB Error on Ping(): ", err)
		os.Exit(-1)
	}
}

func csrfSecret() string {
	file, err := os.Open("csrf-secret.txt")
	if err != nil {
		fmt.Println("Error: cannot open csrf-secret.txt (run gen-csrf.sh to generate)")
		os.Exit(-1)
	}
	defer file.Close();
	var bytes []byte = make([]byte, 32)
	n, err := file.Read(bytes)
	if err != nil || n != 32 {
		fmt.Println("Error: cannot open csrf-secret.txt (run gen-csrf.sh to generate)")
	}
	return string(bytes)
}

func main() {
	fmt.Println("transmet ", VERSION)

	envFlag := flag.String("env", "local", "load config/{env}.json")
	flag.Parse()

	fmt.Println("Loading...")

	loadConfig(*envFlag)
	dbConnect()
	initTemplates()
	r := init_route_handlers()

	fmt.Println("Listening on", config.Port, "...")
	err := http.ListenAndServe(":"+config.Port, csrf.Protect([]byte(csrfSecret()))(r))
	if err != nil {
		fmt.Println("Fatal Error: ", err)
	}

	db.Close()
}