package Auth

import (
	"database/sql/driver"
	"encoding/json"
	"net/http"
	"time"

	"git.tovijaeschke.xyz/tovi/Envelope/Backend/Database"
	"git.tovijaeschke.xyz/tovi/Envelope/Backend/Models"
)

type credentials struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

type loginResponse struct {
	Status               string `json:"status"`
	Message              string `json:"message"`
	AsymmetricPublicKey  string `json:"asymmetric_public_key"`
	AsymmetricPrivateKey string `json:"asymmetric_private_key"`
	UserID               string `json:"user_id"`
	Username             string `json:"username"`
	MessageExpiryDefault string `json:"message_expiry_default"`
}

func makeLoginResponse(w http.ResponseWriter, code int, message, pubKey, privKey string, user Models.User) {
	var (
		status           = "error"
		messageExpiryRaw driver.Value
		messageExpiry    string
		returnJSON       []byte
		err              error
	)
	if code >= 200 && code <= 300 {
		status = "success"
	}

	messageExpiryRaw, _ = user.MessageExpiryDefault.Value()
	messageExpiry, _ = messageExpiryRaw.(string)

	returnJSON, err = json.MarshalIndent(loginResponse{
		Status:               status,
		Message:              message,
		AsymmetricPublicKey:  pubKey,
		AsymmetricPrivateKey: privKey,
		UserID:               user.ID.String(),
		Username:             user.Username,
		MessageExpiryDefault: messageExpiry,
	}, "", "  ")
	if err != nil {
		http.Error(w, "Error", http.StatusInternalServerError)
		return
	}

	// Return updated json
	w.WriteHeader(code)
	w.Write(returnJSON)
}

// Login logs the user into the system
func Login(w http.ResponseWriter, r *http.Request) {
	var (
		creds     credentials
		userData  Models.User
		session   Models.Session
		expiresAt time.Time
		err       error
	)

	err = json.NewDecoder(r.Body).Decode(&creds)
	if err != nil {
		makeLoginResponse(w, http.StatusInternalServerError, "An error occurred", "", "", userData)
		return
	}

	userData, err = Database.GetUserByUsername(creds.Username)
	if err != nil {
		makeLoginResponse(w, http.StatusUnauthorized, "An error occurred", "", "", userData)
		return
	}

	if !CheckPasswordHash(creds.Password, userData.Password) {
		makeLoginResponse(w, http.StatusUnauthorized, "An error occurred", "", "", userData)
		return
	}

	// TODO: Revisit before production
	expiresAt = time.Now().Add(12 * time.Hour)

	session = Models.Session{
		UserID: userData.ID,
		Expiry: expiresAt,
	}

	err = Database.CreateSession(&session)
	if err != nil {
		makeLoginResponse(w, http.StatusUnauthorized, "An error occurred", "", "", userData)
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:    "session_token",
		Value:   session.ID.String(),
		Expires: expiresAt,
	})

	makeLoginResponse(
		w,
		http.StatusOK,
		"Successfully logged in",
		userData.AsymmetricPublicKey,
		userData.AsymmetricPrivateKey,
		userData,
	)
}