package main

import (
	"context"
	"crypto/md5"
	"database/sql"
	"embed"
	"encoding/hex"
	"encoding/json"
	"io/fs"
	"log"
	"os"
	"sync"
	"time"

	"github.com/google/uuid"
	"github.com/joho/godotenv"

	"github.com/ryanhamamura/c4/auth"
	"github.com/ryanhamamura/c4/db"
	"github.com/ryanhamamura/c4/db/gen"
	"github.com/ryanhamamura/c4/game"
	"github.com/ryanhamamura/c4/snake"
	"github.com/ryanhamamura/c4/ui"
	"github.com/ryanhamamura/via"
	"github.com/ryanhamamura/via/h"
)

var (
	store         = game.NewGameStore()
	snakeStore    = snake.NewSnakeStore()
	queries       *gen.Queries
	chatPersister *db.ChatPersister
)

//go:embed assets
var assets embed.FS

func DaisyUIPlugin(v *via.V) {
	css, _ := fs.ReadFile(assets, "assets/css/output.css")
	sum := md5.Sum(css)
	version := hex.EncodeToString(sum[:4])
	v.AppendToHead(h.Link(h.Rel("stylesheet"), h.Href("/assets/css/output.css?v="+version)))
}

func port() string {
	if p := os.Getenv("PORT"); p != "" {
		return p
	}
	return "7331"
}

func main() {
	_ = godotenv.Load()

	if err := os.MkdirAll("data", 0o755); err != nil {
		log.Fatal(err)
	}
	if err := db.Init("data/c4.db"); err != nil {
		log.Fatal(err)
	}
	queries = gen.New(db.DB)
	store.SetPersister(db.NewGamePersister(queries))
	snakeStore.SetPersister(db.NewSnakePersister(queries))
	chatPersister = db.NewChatPersister(queries)

	sessionManager, err := via.NewSQLiteSessionManager(db.DB)
	if err != nil {
		log.Fatal(err)
	}

	v := via.New()
	v.Config(via.Options{
		LogLevel:            via.LogLevelDebug,
		DocumentTitle:       "Game Lobby",
		ServerAddress:       ":" + port(),
		SessionManager:      sessionManager,
		Plugins:             []via.Plugin{DaisyUIPlugin},
		ContextSuspendAfter: 5 * time.Minute,
		ContextTTL:          30 * time.Minute,
	})

	subFS, _ := fs.Sub(assets, "assets")
	v.StaticFS("/assets/", subFS)

	store.SetPubSub(v.PubSub())
	snakeStore.SetPubSub(v.PubSub())

	// Home page - tabbed lobby
	v.Page("/", func(c *via.Context) {
		userID := c.Session().GetString("user_id")
		username := c.Session().GetString("username")
		isLoggedIn := userID != ""

		var userGames []ui.GameListItem
		if isLoggedIn {
			ctx := context.Background()
			games, err := queries.GetUserActiveGames(ctx, sql.NullString{String: userID, Valid: true})
			if err == nil {
				for _, g := range games {
					isMyTurn := g.Status == 1 && g.CurrentTurn == g.MyColor
					userGames = append(userGames, ui.GameListItem{
						ID:           g.ID,
						Status:       int(g.Status),
						OpponentName: g.OpponentNickname.String,
						IsMyTurn:     isMyTurn,
						LastPlayed:   g.UpdatedAt.Time,
					})
				}
			}
		}

		nickname := c.Signal("")
		if isLoggedIn {
			nickname = c.Signal(username)
		}
		activeTab := c.Signal("connect4")

		logout := c.Action(func() {
			c.Session().Clear()
			c.Redirect("/")
		})

		createGame := c.Action(func() {
			name := nickname.String()
			if name == "" {
				return
			}
			c.Session().Set("nickname", name)

			gi := store.Create()
			c.Redirectf("/game/%s", gi.ID())
		})

		deleteGame := func(id string) h.H {
			return c.Action(func() {
				for _, g := range userGames {
					if g.ID == id {
						store.Delete(id)
						break
					}
				}
				c.Redirect("/")
			}).OnClick()
		}

		tabClickConnect4 := c.Action(func() {
			activeTab.SetValue("connect4")
			c.Sync()
		})

		tabClickSnake := c.Action(func() {
			activeTab.SetValue("snake")
			c.Sync()
		})

		snakeNickname := c.Signal("")
		if isLoggedIn {
			snakeNickname = c.Signal(username)
		}

		// Speed selection signal (index into SpeedPresets, default to Normal which is index 1)
		selectedSpeedIndex := c.Signal(1)

		// Speed selector actions
		var speedSelectClicks []h.H
		for i := range snake.SpeedPresets {
			idx := i
			speedSelectClicks = append(speedSelectClicks, c.Action(func() {
				selectedSpeedIndex.SetValue(idx)
				c.Sync()
			}).OnClick())
		}

		// Snake create game actions — one per preset for solo and multiplayer
		var snakeSoloClicks []h.H
		var snakeMultiClicks []h.H
		for _, preset := range snake.GridPresets {
			w, ht := preset.Width, preset.Height
			snakeSoloClicks = append(snakeSoloClicks, c.Action(func() {
				name := snakeNickname.String()
				if name == "" {
					return
				}
				c.Session().Set("nickname", name)
				speedIdx := selectedSpeedIndex.Int()
				speed := snake.DefaultSpeed
				if speedIdx >= 0 && speedIdx < len(snake.SpeedPresets) {
					speed = snake.SpeedPresets[speedIdx].Speed
				}
				si := snakeStore.Create(w, ht, snake.ModeSinglePlayer, speed)
				c.Redirectf("/snake/%s", si.ID())
			}).OnClick())
			snakeMultiClicks = append(snakeMultiClicks, c.Action(func() {
				name := snakeNickname.String()
				if name == "" {
					return
				}
				c.Session().Set("nickname", name)
				speedIdx := selectedSpeedIndex.Int()
				speed := snake.DefaultSpeed
				if speedIdx >= 0 && speedIdx < len(snake.SpeedPresets) {
					speed = snake.SpeedPresets[speedIdx].Speed
				}
				si := snakeStore.Create(w, ht, snake.ModeMultiplayer, speed)
				c.Redirectf("/snake/%s", si.ID())
			}).OnClick())
		}

		c.View(func() h.H {
			return ui.LobbyView(ui.LobbyProps{
				NicknameBind:       nickname.Bind(),
				CreateGameKeyDown:  createGame.OnKeyDown("Enter"),
				CreateGameClick:    createGame.OnClick(),
				IsLoggedIn:         isLoggedIn,
				Username:           username,
				LogoutClick:        logout.OnClick(),
				UserGames:          userGames,
				DeleteGameClick:    deleteGame,
				ActiveTab:          activeTab.String(),
				TabClickConnect4:   tabClickConnect4.OnClick(),
				TabClickSnake:      tabClickSnake.OnClick(),
				SnakeNicknameBind:  snakeNickname.Bind(),
				SnakeSoloClicks:    snakeSoloClicks,
				SnakeMultiClicks:   snakeMultiClicks,
				ActiveSnakeGames:   snakeStore.ActiveGames(),
				SelectedSpeedIndex: selectedSpeedIndex.Int(),
				SpeedSelectClicks:  speedSelectClicks,
			})
		})
	})

	// Login page
	v.Page("/login", func(c *via.Context) {
		username := c.Signal("")
		password := c.Signal("")
		errorMsg := c.Signal("")

		login := c.Action(func() {
			ctx := context.Background()
			user, err := queries.GetUserByUsername(ctx, username.String())
			if err == sql.ErrNoRows {
				errorMsg.SetValue("Invalid username or password")
				c.Sync()
				return
			}
			if err != nil {
				errorMsg.SetValue("An error occurred")
				c.Sync()
				return
			}
			if !auth.CheckPassword(password.String(), user.PasswordHash) {
				errorMsg.SetValue("Invalid username or password")
				c.Sync()
				return
			}

			c.Session().RenewToken()
			c.Session().Set("user_id", user.ID)
			c.Session().Set("username", user.Username)
			c.Session().Set("nickname", user.Username)

			returnURL := c.Session().GetString("return_url")
			if returnURL != "" {
				c.Session().Set("return_url", "")
				c.Redirect(returnURL)
			} else {
				c.Redirect("/")
			}
		})

		c.View(func() h.H {
			return ui.LoginView(
				username.Bind(),
				password.Bind(),
				login.OnKeyDown("Enter"),
				login.OnClick(),
				errorMsg.String(),
			)
		})
	})

	// Register page
	v.Page("/register", func(c *via.Context) {
		username := c.Signal("")
		password := c.Signal("")
		confirm := c.Signal("")
		errorMsg := c.Signal("")

		register := c.Action(func() {
			if err := auth.ValidateUsername(username.String()); err != nil {
				errorMsg.SetValue(err.Error())
				c.Sync()
				return
			}
			if err := auth.ValidatePassword(password.String()); err != nil {
				errorMsg.SetValue(err.Error())
				c.Sync()
				return
			}
			if password.String() != confirm.String() {
				errorMsg.SetValue("Passwords do not match")
				c.Sync()
				return
			}

			hash, err := auth.HashPassword(password.String())
			if err != nil {
				errorMsg.SetValue("An error occurred")
				c.Sync()
				return
			}

			ctx := context.Background()
			id := uuid.New().String()
			user, err := queries.CreateUser(ctx, gen.CreateUserParams{
				ID:           id,
				Username:     username.String(),
				PasswordHash: hash,
			})
			if err != nil {
				errorMsg.SetValue("Username already taken")
				c.Sync()
				return
			}

			c.Session().RenewToken()
			c.Session().Set("user_id", user.ID)
			c.Session().Set("username", user.Username)
			c.Session().Set("nickname", user.Username)

			returnURL := c.Session().GetString("return_url")
			if returnURL != "" {
				c.Session().Set("return_url", "")
				c.Redirect(returnURL)
			} else {
				c.Redirect("/")
			}
		})

		c.View(func() h.H {
			return ui.RegisterView(
				username.Bind(),
				password.Bind(),
				confirm.Bind(),
				register.OnKeyDown("Enter"),
				register.OnClick(),
				errorMsg.String(),
			)
		})
	})

	// Connect 4 game page
	v.Page("/game/{game_id}", func(c *via.Context) {
		gameID := c.GetPathParam("game_id")
		sessionNickname := c.Session().GetString("nickname")
		sessionUserID := c.Session().GetString("user_id")

		nickname := c.Signal(sessionNickname)
		colSignal := c.Signal(0)
		showGuestPrompt := c.Signal(false)
		chatMsg := c.Signal("")
		chatMessages, _ := chatPersister.LoadChatMessages(gameID)
		var chatMu sync.Mutex

		goToLogin := c.Action(func() {
			c.Session().Set("return_url", "/game/"+gameID)
			c.Redirect("/login")
		})

		goToRegister := c.Action(func() {
			c.Session().Set("return_url", "/game/"+gameID)
			c.Redirect("/register")
		})

		continueAsGuest := c.Action(func() {
			showGuestPrompt.SetValue(true)
			c.Sync()
		})

		var gi *game.GameInstance
		var gameExists bool

		if gameID != "" {
			gi, gameExists = store.Get(gameID)
		}

		playerID := game.PlayerID(c.Session().GetString("player_id"))
		if playerID == "" {
			playerID = game.PlayerID(game.GenerateID(8))
			c.Session().Set("player_id", string(playerID))
		}

		if sessionUserID != "" {
			playerID = game.PlayerID(sessionUserID)
		}

		setNickname := c.Action(func() {
			if gi == nil {
				return
			}
			name := nickname.String()
			if name == "" {
				return
			}
			c.Session().Set("nickname", name)

			if gi.GetPlayerColor(playerID) == 0 {
				player := &game.Player{
					ID:       playerID,
					Nickname: name,
				}
				if sessionUserID != "" {
					player.UserID = &sessionUserID
				}
				gi.Join(&game.PlayerSession{
					Player: player,
				})
			}
			c.Sync()
		})

		dropPiece := c.Action(func() {
			if gi == nil {
				return
			}
			myColor := gi.GetPlayerColor(playerID)
			if myColor == 0 {
				return
			}
			col := colSignal.Int()
			gi.DropPiece(col, myColor)
			c.Sync()
		})

		createRematch := c.Action(func() {
			if gi == nil {
				return
			}
			newGI := gi.CreateRematch(store)
			if newGI != nil {
				c.Redirectf("/game/%s", newGI.ID())
			}
		})

		sendChat := c.Action(func() {
			msg := chatMsg.String()
			if msg == "" || gi == nil {
				return
			}
			color := gi.GetPlayerColor(playerID)
			if color == 0 {
				return
			}
			g := gi.GetGame()
			nick := ""
			for _, p := range g.Players {
				if p != nil && p.ID == playerID {
					nick = p.Nickname
					break
				}
			}
			cm := ui.C4ChatMessage{
				Nickname: nick,
				Color:    color,
				Message:  msg,
				Time:     time.Now().UnixMilli(),
			}
			chatPersister.SaveChatMessage(gameID, cm)
			data, err := json.Marshal(cm)
			if err != nil {
				return
			}
			c.Publish("game.chat."+gameID, data)
			chatMsg.SetValue("")
		})

		if gameExists {
			c.Subscribe("game."+gameID, func(data []byte) { c.Sync() })

			c.Subscribe("game.chat."+gameID, func(data []byte) {
				var cm ui.C4ChatMessage
				if err := json.Unmarshal(data, &cm); err != nil {
					return
				}
				chatMu.Lock()
				chatMessages = append(chatMessages, cm)
				if len(chatMessages) > 50 {
					chatMessages = chatMessages[len(chatMessages)-50:]
				}
				chatMu.Unlock()
				c.Sync()
			})
		}

		if gameExists && sessionNickname != "" && gi.GetPlayerColor(playerID) == 0 {
			player := &game.Player{
				ID:       playerID,
				Nickname: sessionNickname,
			}
			if sessionUserID != "" {
				player.UserID = &sessionUserID
			}
			gi.Join(&game.PlayerSession{
				Player: player,
			})
		}

		c.View(func() h.H {
			if !gameExists {
				c.Redirect("/")
				return h.Div()
			}

			myColor := gi.GetPlayerColor(playerID)

			if myColor == 0 {
				if sessionUserID == "" && !showGuestPrompt.Bool() {
					return ui.GameJoinPrompt(
						goToLogin.OnClick(),
						continueAsGuest.OnClick(),
						goToRegister.OnClick(),
					)
				}
				return ui.NicknamePrompt(
					nickname.Bind(),
					setNickname.OnKeyDown("Enter"),
					setNickname.OnClick(),
				)
			}

			g := gi.GetGame()

			columnClick := func(col int) h.H {
				return dropPiece.OnClick(via.WithSignalInt(colSignal, col))
			}

			chatMu.Lock()
			msgs := make([]ui.C4ChatMessage, len(chatMessages))
			copy(msgs, chatMessages)
			chatMu.Unlock()
			chat := ui.C4Chat(msgs, chatMsg.Bind(), sendChat.OnClick(), sendChat.OnKeyDown("Enter"))

			var content []h.H
			content = append(content,
				ui.BackToLobby(),
				ui.StealthTitle("text-3xl font-bold"),
				ui.PlayerInfo(g, myColor),
				ui.StatusBanner(g, myColor, createRematch.OnClick()),
				h.Div(h.Class("c4-game-area"), ui.BoardComponent(g, columnClick, myColor), chat),
			)

			if g.Status == game.StatusWaitingForPlayer {
				content = append(content, ui.InviteLink(g.ID))
			}

			mainAttrs := []h.H{h.Class("flex flex-col items-center gap-4 p-4")}
			mainAttrs = append(mainAttrs, content...)
			return h.Main(mainAttrs...)
		})
	})

	// Snake game page
	v.Page("/snake/{game_id}", func(c *via.Context) {
		gameID := c.GetPathParam("game_id")
		sessionNickname := c.Session().GetString("nickname")
		sessionUserID := c.Session().GetString("user_id")

		nickname := c.Signal(sessionNickname)
		showGuestPrompt := c.Signal(false)

		goToLogin := c.Action(func() {
			c.Session().Set("return_url", "/snake/"+gameID)
			c.Redirect("/login")
		})

		goToRegister := c.Action(func() {
			c.Session().Set("return_url", "/snake/"+gameID)
			c.Redirect("/register")
		})

		continueAsGuest := c.Action(func() {
			showGuestPrompt.SetValue(true)
			c.Sync()
		})

		var si *snake.SnakeGameInstance
		var gameExists bool

		if gameID != "" {
			si, gameExists = snakeStore.Get(gameID)
		}

		playerID := snake.PlayerID(c.Session().GetString("player_id"))
		if playerID == "" {
			pid := game.GenerateID(8)
			playerID = snake.PlayerID(pid)
			c.Session().Set("player_id", pid)
		}
		if sessionUserID != "" {
			playerID = snake.PlayerID(sessionUserID)
		}

		setNickname := c.Action(func() {
			if si == nil {
				return
			}
			name := nickname.String()
			if name == "" {
				return
			}
			c.Session().Set("nickname", name)

			if si.GetPlayerSlot(playerID) < 0 {
				player := &snake.Player{
					ID:       playerID,
					Nickname: name,
				}
				if sessionUserID != "" {
					player.UserID = &sessionUserID
				}
				si.Join(player)
			}
			c.Sync()
		})

		// Direction input: single action with a direction signal
		dirSignal := c.Signal(-1)
		handleDir := c.Action(func() {
			if si == nil {
				return
			}
			slot := si.GetPlayerSlot(playerID)
			if slot < 0 {
				return
			}
			dir := snake.Direction(dirSignal.Int())
			si.SetDirection(slot, dir)
		})

		createRematch := c.Action(func() {
			if si == nil {
				return
			}
			newSI := si.CreateRematch()
			if newSI != nil {
				c.Redirectf("/snake/%s", newSI.ID())
			}
		})

		chatMsg := c.Signal("")
		var chatMessages []ui.ChatMessage
		var chatMu sync.Mutex

		sendChat := c.Action(func() {
			msg := chatMsg.String()
			if msg == "" || si == nil {
				return
			}
			slot := si.GetPlayerSlot(playerID)
			if slot < 0 {
				return
			}
			cm := ui.ChatMessage{
				Nickname: si.GetGame().Players[slot].Nickname,
				Slot:     slot,
				Message:  msg,
				Time:     time.Now().UnixMilli(),
			}
			data, err := json.Marshal(cm)
			if err != nil {
				return
			}
			c.Publish("snake.chat."+gameID, data)
			chatMsg.SetValue("")
		})

		if gameExists {
			c.Subscribe("snake."+gameID, func(data []byte) { c.Sync() })

			if si.GetGame().Mode == snake.ModeMultiplayer {
				c.Subscribe("snake.chat."+gameID, func(data []byte) {
					var cm ui.ChatMessage
					if err := json.Unmarshal(data, &cm); err != nil {
						return
					}
					chatMu.Lock()
					chatMessages = append(chatMessages, cm)
					if len(chatMessages) > 50 {
						chatMessages = chatMessages[len(chatMessages)-50:]
					}
					chatMu.Unlock()
					c.Sync()
				})
			}
		}

		// Auto-join if nickname exists
		if gameExists && sessionNickname != "" && si.GetPlayerSlot(playerID) < 0 {
			player := &snake.Player{
				ID:       playerID,
				Nickname: sessionNickname,
			}
			if sessionUserID != "" {
				player.UserID = &sessionUserID
			}
			si.Join(player)
		}

		c.View(func() h.H {
			if !gameExists {
				c.Redirect("/")
				return h.Div()
			}

			mySlot := si.GetPlayerSlot(playerID)

			if mySlot < 0 {
				if sessionUserID == "" && !showGuestPrompt.Bool() {
					return ui.GameJoinPrompt(
						goToLogin.OnClick(),
						continueAsGuest.OnClick(),
						goToRegister.OnClick(),
					)
				}
				return ui.NicknamePrompt(
					nickname.Bind(),
					setNickname.OnKeyDown("Enter"),
					setNickname.OnClick(),
				)
			}

			sg := si.GetGame()

			var content []h.H
			content = append(content,
				ui.BackToLobby(),
				h.H1(h.Class("text-3xl font-bold"), h.Text("~~~~")),
				ui.SnakePlayerList(sg, mySlot),
				ui.SnakeStatusBanner(sg, mySlot, createRematch.OnClick()),
			)

			if sg.Status == snake.StatusInProgress || sg.Status == snake.StatusFinished {
				board := ui.SnakeBoard(sg)

				if sg.Mode == snake.ModeMultiplayer {
					chatMu.Lock()
					msgs := make([]ui.ChatMessage, len(chatMessages))
					copy(msgs, chatMessages)
					chatMu.Unlock()
					chat := ui.SnakeChat(msgs, chatMsg.Bind(), sendChat.OnClick(), sendChat.OnKeyDown("Enter"))
					content = append(content, h.Div(h.Class("snake-game-area"), board, chat))
				} else {
					content = append(content, board)
				}
			} else if sg.Mode == snake.ModeMultiplayer {
				// Show chat even before game starts (waiting/countdown)
				chatMu.Lock()
				msgs := make([]ui.ChatMessage, len(chatMessages))
				copy(msgs, chatMessages)
				chatMu.Unlock()
				content = append(content, ui.SnakeChat(msgs, chatMsg.Bind(), sendChat.OnClick(), sendChat.OnKeyDown("Enter")))
			}

			// Only show invite link for multiplayer games
			if sg.Mode == snake.ModeMultiplayer && (sg.Status == snake.StatusWaitingForPlayers || sg.Status == snake.StatusCountdown) {
				content = append(content, ui.SnakeInviteLink(sg.ID))
			}

			wrapperAttrs := []h.H{
				h.Class("snake-wrapper flex flex-col items-center gap-4 p-4"),
				via.OnKeyDownMap(
					via.KeyBind("w", handleDir, via.WithSignalInt(dirSignal, int(snake.DirUp)), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("a", handleDir, via.WithSignalInt(dirSignal, int(snake.DirLeft)), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("s", handleDir, via.WithSignalInt(dirSignal, int(snake.DirDown)), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("d", handleDir, via.WithSignalInt(dirSignal, int(snake.DirRight)), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("ArrowUp", handleDir, via.WithSignalInt(dirSignal, int(snake.DirUp)), via.WithPreventDefault(), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("ArrowLeft", handleDir, via.WithSignalInt(dirSignal, int(snake.DirLeft)), via.WithPreventDefault(), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("ArrowDown", handleDir, via.WithSignalInt(dirSignal, int(snake.DirDown)), via.WithPreventDefault(), via.WithThrottle(100*time.Millisecond)),
					via.KeyBind("ArrowRight", handleDir, via.WithSignalInt(dirSignal, int(snake.DirRight)), via.WithPreventDefault(), via.WithThrottle(100*time.Millisecond)),
				),
			}

			wrapperAttrs = append(wrapperAttrs, content...)
			return h.Main(wrapperAttrs...)
		})
	})

	v.Start()
}