package main

import (
	"context"
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"strings"

	"golang.org/x/crypto/bcrypt"

	_ "github.com/mattn/go-sqlite3"

	"stevenlr.com/timer/model"
	"stevenlr.com/timer/utils"
	"stevenlr.com/timer/view"
)

type TimerServer struct {
	db       *sql.DB
	sessions Sessions
}

func (server *TimerServer) findCurrentUser(w http.ResponseWriter, r *http.Request) *model.User {
	return server.sessions.FindCurrentUser(server.db, w, r)
}

func (server *TimerServer) handleNotFound(w http.ResponseWriter, _ *http.Request) {
	w.WriteHeader(http.StatusNotFound)
	view.Error404().Render(context.Background(), w)
}

func (server *TimerServer) handleMain(w http.ResponseWriter, r *http.Request) {
	currentUser := server.findCurrentUser(w, r)
	if r.URL.Path == "/" {
		timers := make([]model.Timer, 0)
		if currentUser != nil {
			timers = model.GetTimersForUser(server.db, currentUser.Id)
		}
		view.Main(view.TimersList(timers, currentUser != nil), currentUser).Render(context.Background(), w)
	} else {
		server.handleNotFound(w, r)
	}
}

func (server *TimerServer) handleTimer(w http.ResponseWriter, r *http.Request) {
	currentUser := server.findCurrentUser(w, r)
	if currentUser == nil {
		server.handleNotFound(w, r)
		return
	}

	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		server.handleNotFound(w, r)
		return
	}

	timer := model.GetTimerForUser(server.db, id, currentUser.Id)
	if timer != nil && timer.Owner == currentUser.Id {
		view.Main(view.TimerView(*timer), currentUser).Render(context.Background(), w)
	} else {
		server.handleNotFound(w, r)
	}
}

func (server *TimerServer) handleTimerAddTimeCommon(w http.ResponseWriter, r *http.Request, timer *model.Timer) bool {
	if timer.IsFinished() {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Timer already finished"))
		return false
	}

	duration, err := utils.ParseDuration(r.FormValue("timeToAdd"))
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(err.Error()))
		return false
	}

	timer.EndTime.Add(duration)
	res := model.UpdateTimerEndTime(server.db, timer.Id, timer.EndTime, timer.Owner)
	if !res {
		w.WriteHeader(http.StatusInternalServerError)
		return false
	}

	return true
}

func (server *TimerServer) handleTimerAddTime(w http.ResponseWriter, r *http.Request) {
	currentUser := server.findCurrentUser(w, r)
	if currentUser == nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	timer := model.GetTimerForUser(server.db, id, currentUser.Id)
	if timer == nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	if !server.handleTimerAddTimeCommon(w, r, timer) {
		return
	}

	view.TimerInfo(*timer).Render(context.Background(), w)
}

func (server *TimerServer) handleApiTimerAddTime(w http.ResponseWriter, r *http.Request) {
	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	timer := model.GetTimerWithToken(server.db, id, r.FormValue("token"))
	if timer == nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	if !server.handleTimerAddTimeCommon(w, r, timer) {
		return
	}
}

func (server *TimerServer) handleGetTimerToken(w http.ResponseWriter, r *http.Request) {
	currentUser := server.findCurrentUser(w, r)
	if currentUser == nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	timer := model.GetTimerForUser(server.db, id, currentUser.Id)
	if timer == nil {
		server.handleNotFound(w, r)
		return
	}

	w.Write([]byte(fmt.Sprint("<code>", timer.Token, "</code>")))
}

func (server *TimerServer) handleResetTimerToken(w http.ResponseWriter, r *http.Request) {
	currentUser := server.findCurrentUser(w, r)
	if currentUser == nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	timer := model.GetTimerForUser(server.db, id, currentUser.Id)
	if timer == nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	res := model.RegenerateTimerToken(server.db, timer.Id, currentUser.Id)
	if !res {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	view.TimerTokenForm(*timer).Render(context.Background(), w)
}

func (server *TimerServer) handleDeleteTimer(w http.ResponseWriter, r *http.Request) {
	user := server.findCurrentUser(w, r)
	if user == nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	var id model.UUID
	if err := id.Scan(r.PathValue("timerId")); err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	success := model.DeleteTimer(server.db, id, user.Id)
	if !success {
		w.WriteHeader(http.StatusNotFound)
	}
}

func (server *TimerServer) handleCreateTimer(w http.ResponseWriter, r *http.Request) {
	timerName := strings.TrimSpace(r.FormValue("timerName"))

	user := server.findCurrentUser(w, r)
	if user == nil {
		w.WriteHeader(http.StatusBadRequest)
		view.TimerCreateForm(timerName, "You are not signed in").Render(context.Background(), w)
		return
	}

	days, err := utils.ParseNumber(r.FormValue("days"))
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		view.TimerCreateForm(timerName, "Error parsing days").Render(context.Background(), w)
		return
	}

	hours, err := utils.ParseNumber(r.FormValue("hours"))
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		view.TimerCreateForm(timerName, "Error parsing hours").Render(context.Background(), w)
		return
	}

	tx, err := server.db.Begin()
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		view.TimerCreateForm(timerName, "Internal server error").Render(context.Background(), w)
		return
	}
	defer tx.Rollback()

	if timerName == "" {
		w.WriteHeader(http.StatusBadRequest)
		view.TimerCreateForm("", "Timer name cannot be empty").Render(context.Background(), w)
		return
	}

	err = model.InsertTimer(tx, timerName, int(((max(days, 0)*24)+max(hours, 0))*3600), user.Id)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		view.TimerCreateForm(timerName, "Internal server error").Render(context.Background(), w)
		return
	}

	tx.Commit()

	timers := model.GetTimersForUser(server.db, user.Id)
	view.TimersList(timers, user != nil).Render(context.Background(), w)
}

func (server *TimerServer) handlePostLogin(w http.ResponseWriter, r *http.Request) {
	if server.findCurrentUser(w, r) != nil {
		utils.HtmxRedirect(w, "/")
		return
	}

	userName := r.FormValue("user")
	userPass := r.FormValue("password")

	user := model.GetUserByName(server.db, userName)
	if user == nil {
		w.WriteHeader(http.StatusBadRequest)
		view.LoginFormError(nil, "Incorrect credentials").Render(context.Background(), w)
		return
	}

	err := bcrypt.CompareHashAndPassword(user.Password, []byte(userPass))
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		view.LoginFormError(nil, "Incorrect credentials").Render(context.Background(), w)
		return
	}

	if err := server.sessions.StartSession(user.Id, w); err == nil {
		utils.HtmxRedirect(w, "/")
	} else {
		w.WriteHeader(http.StatusInternalServerError)
		view.LoginFormError(nil, "Internal server error").Render(context.Background(), w)
	}
}

func (server *TimerServer) handlePostLogout(w http.ResponseWriter, r *http.Request) {
	server.sessions.EndSession(w, r)
	utils.HtmxRedirect(w, "/")
}

func main() {
	log.Println("Starting...")

	db, err := sql.Open("sqlite3", "file:timer.db")
	if err != nil {
		log.Fatalln(err)
	}
	defer db.Close()

	if err := InitializeDatabase(db); err != nil {
		log.Fatalln(err)
	}

	myServer := TimerServer{db: db, sessions: MakeSessions()}

	fs := http.FileServer(http.Dir("static/"))
	http.Handle("GET /static/", http.StripPrefix("/static/", fs))

	http.HandleFunc("POST /login", myServer.handlePostLogin)
	http.HandleFunc("POST /logout", myServer.handlePostLogout)
	http.HandleFunc("GET /timer/{timerId}", myServer.handleTimer)
	http.HandleFunc("POST /timer/{timerId}/addTime", myServer.handleTimerAddTime)
	http.HandleFunc("POST /api/timer/{timerId}/addTime", myServer.handleApiTimerAddTime)
	http.HandleFunc("DELETE /timer/{timerId}", myServer.handleDeleteTimer)
	http.HandleFunc("POST /timer/{timerId}/resetToken", myServer.handleResetTimerToken)
	http.HandleFunc("GET /timer/{timerId}/token", myServer.handleGetTimerToken)
	http.HandleFunc("PUT /timer", myServer.handleCreateTimer)
	http.HandleFunc("GET /", myServer.handleMain)

	log.Println("Started!")
	http.ListenAndServe("0.0.0.0:80", nil)
}