package handlers

import (
    "log"
    "net/http"
    "threadr/models"
    "github.com/gorilla/sessions"
)

func LoginHandler(app *App) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        session := r.Context().Value("session").(*sessions.Session)
        if r.Method == http.MethodPost {
            username := r.FormValue("username")
            password := r.FormValue("password")
            user, err := models.GetUserByUsername(app.DB, username)
            if err != nil {
                log.Printf("Error fetching user in LoginHandler: %v", err)
                http.Error(w, "Internal Server Error", http.StatusInternalServerError)
                return
            }
            if user == nil || !models.CheckPassword(password, user.AuthenticationSalt, user.AuthenticationAlgorithm, user.AuthenticationString) {
                http.Redirect(w, r, app.Config.ThreadrDir+"/login/?error=invalid", http.StatusFound)
                return
            }
            session.Values["user_id"] = user.ID
            session.Values["user_ip"] = r.RemoteAddr
            session.Values["user_agent"] = r.UserAgent()
            if err := session.Save(r, w); err != nil {
                log.Printf("Error saving session: %v", err)
                http.Error(w, "Internal Server Error", http.StatusInternalServerError)
                return
            }
            http.Redirect(w, r, app.Config.ThreadrDir+"/userhome/", http.StatusFound)
            return
        }

        data := struct {
            PageData
            Error string
        }{
            PageData: PageData{
                Title:            "ThreadR - Login",
                Navbar:           "login",
                LoggedIn:         false,
                BasePath:         app.Config.ThreadrDir,
                StaticPath:       app.Config.ThreadrDir + "/static",
                CurrentURL:       r.URL.Path,
            },
            Error: "",
        }
        if r.URL.Query().Get("error") == "invalid" {
            data.Error = "Invalid username or password"
        }

        if err := app.Tmpl.ExecuteTemplate(w, "login", data); err != nil {
            log.Printf("Error executing template in LoginHandler: %v", err)
            http.Error(w, "Internal Server Error", http.StatusInternalServerError)
            return
        }
    }
}