package main

import (
	"context"
	"database/sql"
	_ "embed"
	"log"
	"net/http"

	"github.com/google/uuid"
	"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/ui"
	"github.com/ryanhamamura/via"
	"github.com/ryanhamamura/via/h"
	"github.com/ryanhamamura/via/vianats"
)

var store = game.NewGameStore()
var queries *gen.Queries

//go:embed assets/css/output.css
var daisyUICSS []byte

func DaisyUIPlugin(v *via.V) {
	v.HTTPServeMux().HandleFunc("GET /_plugins/daisyui/style.css", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/css")
		_, _ = w.Write(daisyUICSS)
	})
	v.AppendToHead(h.Link(h.Rel("stylesheet"), h.Href("/_plugins/daisyui/style.css")))
}

func main() {
	if err := db.Init("c4.db"); err != nil {
		log.Fatal(err)
	}
	queries = gen.New(db.DB)
	store.SetPersister(db.NewGamePersister(queries))

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

	ctx := context.Background()
	ns, err := vianats.New(ctx, "./data/nats")
	if err != nil {
		log.Fatal(err)
	}
	store.SetPubSub(ns)

	v := via.New()
	v.Config(via.Options{
		LogLevel:       via.LogLevelDebug,
		DocumentTitle:  "Connect 4",
		ServerAddress:  ":7331",
		SessionManager: sessionManager,
		PubSub:         ns,
		Plugins:        []via.Plugin{DaisyUIPlugin},
	})

	// Home page - enter nickname and create game
	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)
		}

		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()
		}

		c.View(func() h.H {
			return ui.LobbyView(
				nickname.Bind(),
				createGame.OnKeyDown("Enter"),
				createGame.OnClick(),
				isLoggedIn,
				username,
				logout.OnClick(),
				userGames,
				deleteGame,
			)
		})
	})

	// 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().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().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(),
			)
		})
	})

	// 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)

		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

		// Look up game (may not exist during warmup or invalid ID)
		if gameID != "" {
			gi, gameExists = store.Get(gameID)
		}

		// Generate a stable player ID for this session
		playerID := game.PlayerID(c.Session().GetString("player_id"))
		if playerID == "" {
			playerID = game.PlayerID(game.GenerateID(8))
			c.Session().Set("player_id", string(playerID))
		}

		// Use user_id as player_id if logged in
		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)

			// Try to join if not already in game
			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())
			}
		})

		// Subscribe to game updates so the opponent's moves trigger a re-render
		if gameExists {
			c.Subscribe("game."+gameID, func(data []byte) { c.Sync() })
		}

		// If nickname exists in session and game exists, join immediately
		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 {
			// Game not found - redirect to home
			if !gameExists {
				c.Redirect("/")
				return h.Div()
			}

			myColor := gi.GetPlayerColor(playerID)

			// Need nickname first / not joined yet
			if myColor == 0 {
				// Unauthenticated user who hasn't chosen to continue as guest
				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()

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

			var content []h.H
			content = append(content,
				h.H1(h.Class("text-3xl font-bold"), h.Text("Connect 4")),
				ui.PlayerInfo(g, myColor),
				ui.StatusBanner(g, myColor, createRematch.OnClick()),
				ui.BoardComponent(g, columnClick, myColor),
			)

			// Show invite link when waiting for opponent
			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...)
		})
	})

	v.Start()
}