package main

import (
    "net/http"
    "html/template"
    "fmt"
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
    "golang.org/x/crypto/bcrypt"
)

var (
    templ *template.Template
    err error
    db *sql.DB
)

func init() {
    templ = template.Must(template.ParseGlob("templates/*.html"))
}

func main() {
    handleDbConnection()
    http.Handle("/assets/", http.FileServer(http.Dir(".")))
    http.HandleFunc("/", index)
    http.HandleFunc("/login", login)
    http.HandleFunc("/profile", profile)
    fmt.Println("server running")
    http.ListenAndServe(":8080", nil)
}

func handleDbConnection()  {
    // Create an sql.DB and check for errors
    db, err := sql.Open("mysql", "root:password@/GoStaffManager")
    if err != nil {
        panic(err.Error())
    }
    // sql.DB should be long lived "defer" closes it once this function ends
    defer db.Close()

    // Test the connection to the database
    err = db.Ping()
    if err != nil {
        panic(err.Error())
    } else {
        fmt.Println("working...")
    }
}

func index(res http.ResponseWriter, req *http.Request)  {
    err = templ.ExecuteTemplate(res, "index.html", nil)
    if err != nil {
        fmt.Sprint("error", err)
    }
}

func login(res http.ResponseWriter, req *http.Request)  {
    err = templ.ExecuteTemplate(res, "login.html", nil)
    if err != nil {
        fmt.Sprint("error", err)
    }

    // Grab the username/password from the submitted post form
    username := req.FormValue("username")
    password := req.FormValue("password")

    // Grab from the database
    var (
        uname string
        pword string
    )

    // Search the database for the username provided
    // If it exists grab the password for validation
    err := db.QueryRow("SELECT username, password FROM lecturers WHERE username=?", username).Scan(&uname, &pword)
    // If not then redirect to the login page
    if err != nil {
        http.Redirect(res, req, "/login", 301)
        return
    }
    // Validate the password
    err = bcrypt.CompareHashAndPassword([]byte(pword), []byte(password))
    // If wrong password redirect to the login
    if err != nil {
        http.Redirect(res, req, "/login", 301)
        return
    }

    http.Redirect(res, req, "/profile", 301)
}

func profile(res http.ResponseWriter, req *http.Request)  {
    err = templ.ExecuteTemplate(res, "profile.html", nil)
    if err != nil {
        fmt.Sprint("error", err)
    }
}