package c4game

import (
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/alexedwards/scs/v2"
	"github.com/go-chi/chi/v5"
	"github.com/nats-io/nats.go"
	"github.com/starfederation/datastar-go/datastar"

	"github.com/ryanhamamura/games/chat"
	chatcomponents "github.com/ryanhamamura/games/chat/components"
	"github.com/ryanhamamura/games/connect4"
	"github.com/ryanhamamura/games/db/repository"
	"github.com/ryanhamamura/games/features/c4game/components"
	"github.com/ryanhamamura/games/features/c4game/pages"
	"github.com/ryanhamamura/games/sessions"
)

// c4ChatColors maps player color (1=Red, 2=Yellow) to CSS background colors.
var c4ChatColors = map[int]string{
	0: "#4a2a3a", // color 1 stored as slot 0
	1: "#2a4545", // color 2 stored as slot 1
}

func c4ChatColor(slot int) string {
	if c, ok := c4ChatColors[slot]; ok {
		return c
	}
	return "#666"
}

func c4ChatConfig(gameID string) chatcomponents.Config {
	return chatcomponents.Config{
		CSSPrefix: "c4",
		PostURL:   fmt.Sprintf("/games/%s/chat", gameID),
		Color:     c4ChatColor,
	}
}

func HandleGamePage(store *connect4.Store, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			http.Redirect(w, r, "/", http.StatusFound)
			return
		}

		playerID := sessions.GetPlayerID(sm, r)
		userID := sessions.GetUserID(sm, r)
		nickname := sessions.GetNickname(sm, r)

		// Auto-join if player has a nickname but isn't in the game yet
		if nickname != "" && gi.GetPlayerColor(playerID) == 0 {
			p := &connect4.Player{
				ID:       playerID,
				Nickname: nickname,
			}
			if userID != "" {
				p.UserID = &userID
			}
			gi.Join(&connect4.PlayerSession{Player: p})
		}

		myColor := gi.GetPlayerColor(playerID)

		if myColor == 0 {
			// Player not in game
			isGuest := r.URL.Query().Get("guest") == "1"
			if userID == "" && !isGuest {
				if err := pages.JoinPage(gameID).Render(r.Context(), w); err != nil {
					http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
				}
				return
			}
			if err := pages.NicknamePage(gameID).Render(r.Context(), w); err != nil {
				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
			}
			return
		}

		g := gi.GetGame()
		msgs := chat.LoadMessages(queries, gameID)

		if err := pages.GamePage(g, myColor, msgs, c4ChatConfig(gameID)).Render(r.Context(), w); err != nil {
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		}
	}
}

func HandleGameEvents(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			http.Error(w, "game not found", http.StatusNotFound)
			return
		}

		playerID := sessions.GetPlayerID(sm, r)
		myColor := gi.GetPlayerColor(playerID)

		sse := datastar.NewSSE(w, r, datastar.WithCompression(
			datastar.WithBrotli(datastar.WithBrotliLevel(5)),
		))

		chatCfg := c4ChatConfig(gameID)
		room := chat.NewRoom(nc, "connect4.chat."+gameID, chat.LoadMessages(queries, gameID))

		// Send initial render
		sendGameComponents(sse, gi, myColor, room, chatCfg)

		// Subscribe to game state updates
		gameCh := make(chan *nats.Msg, 64)
		gameSub, err := nc.ChanSubscribe("connect4."+gameID, gameCh)
		if err != nil {
			return
		}
		defer gameSub.Unsubscribe() //nolint:errcheck

		// Subscribe to chat messages
		chatCh, chatSub, err := room.Subscribe()
		if err != nil {
			return
		}
		defer chatSub.Unsubscribe() //nolint:errcheck

		ctx := r.Context()
		for {
			select {
			case <-ctx.Done():
				return
			case <-gameCh:
				myColor = gi.GetPlayerColor(playerID)
				sendGameComponents(sse, gi, myColor, room, chatCfg)
			case msg := <-chatCh:
				_, snapshot := room.Receive(msg.Data)
				if snapshot == nil {
					continue
				}
				if err := sse.PatchElementTempl(chatcomponents.Chat(snapshot, chatCfg), datastar.WithSelectorID("c4-chat")); err != nil {
					return
				}
			}
		}
	}
}

func HandleDropPiece(store *connect4.Store, sm *scs.SessionManager) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			http.Error(w, "game not found", http.StatusNotFound)
			return
		}

		colStr := r.URL.Query().Get("col")
		col, err := strconv.Atoi(colStr)
		if err != nil {
			http.Error(w, "invalid column", http.StatusBadRequest)
			return
		}

		playerID := sessions.GetPlayerID(sm, r)
		myColor := gi.GetPlayerColor(playerID)
		if myColor == 0 {
			http.Error(w, "not in game", http.StatusForbidden)
			return
		}

		gi.DropPiece(col, myColor)
		datastar.NewSSE(w, r)
	}
}

func HandleSendChat(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			http.Error(w, "game not found", http.StatusNotFound)
			return
		}

		type ChatSignals struct {
			ChatMsg string `json:"chatMsg"`
		}
		var signals ChatSignals
		if err := datastar.ReadSignals(r, &signals); err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		if signals.ChatMsg == "" {
			datastar.NewSSE(w, r)
			return
		}

		playerID := sessions.GetPlayerID(sm, r)
		myColor := gi.GetPlayerColor(playerID)
		if myColor == 0 {
			datastar.NewSSE(w, r)
			return
		}

		g := gi.GetGame()
		nick := ""
		for _, p := range g.Players {
			if p != nil && p.ID == playerID {
				nick = p.Nickname
				break
			}
		}

		// Map color (1-based) to slot (0-based) for the unified chat message
		msg := chat.Message{
			Nickname: nick,
			Slot:     myColor - 1,
			Message:  signals.ChatMsg,
			Time:     time.Now().UnixMilli(),
		}
		chat.SaveMessage(queries, gameID, msg)

		room := chat.NewRoom(nc, "connect4.chat."+gameID, nil)
		room.Send(msg)

		sse := datastar.NewSSE(w, r)
		sse.MarshalAndPatchSignals(map[string]any{"chatMsg": ""}) //nolint:errcheck
	}
}

func HandleSetNickname(store *connect4.Store, sm *scs.SessionManager) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			sse := datastar.NewSSE(w, r)
			sse.Redirect("/") //nolint:errcheck
			return
		}

		type NicknameSignals struct {
			Nickname string `json:"nickname"`
		}
		var signals NicknameSignals
		if err := datastar.ReadSignals(r, &signals); err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		if signals.Nickname == "" {
			datastar.NewSSE(w, r)
			return
		}

		sm.Put(r.Context(), "nickname", signals.Nickname)

		playerID := sessions.GetPlayerID(sm, r)
		userID := sessions.GetUserID(sm, r)

		if gi.GetPlayerColor(playerID) == 0 {
			p := &connect4.Player{
				ID:       playerID,
				Nickname: signals.Nickname,
			}
			if userID != "" {
				p.UserID = &userID
			}
			gi.Join(&connect4.PlayerSession{Player: p})
		}

		sse := datastar.NewSSE(w, r)
		sse.Redirect("/games/" + gameID) //nolint:errcheck
	}
}

func HandleRematch(store *connect4.Store, sm *scs.SessionManager) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		gameID := chi.URLParam(r, "id")

		gi, exists := store.Get(gameID)
		if !exists {
			sse := datastar.NewSSE(w, r)
			sse.Redirect("/") //nolint:errcheck
			return
		}

		newGI := gi.CreateRematch(store)
		sse := datastar.NewSSE(w, r)
		if newGI != nil {
			sse.Redirectf("/games/%s", newGI.ID()) //nolint:errcheck
		}
	}
}

// sendGameComponents patches all game-related SSE components.
func sendGameComponents(sse *datastar.ServerSentEventGenerator, gi *connect4.Instance, myColor int, room *chat.Room, chatCfg chatcomponents.Config) {
	g := gi.GetGame()

	sse.PatchElementTempl(components.Board(g, myColor), datastar.WithSelectorID("c4-board"))                 //nolint:errcheck
	sse.PatchElementTempl(components.StatusBanner(g, myColor), datastar.WithSelectorID("c4-status"))         //nolint:errcheck
	sse.PatchElementTempl(components.PlayerInfo(g, myColor), datastar.WithSelectorID("c4-players"))          //nolint:errcheck
	sse.PatchElementTempl(chatcomponents.Chat(room.Messages(), chatCfg), datastar.WithSelectorID("c4-chat")) //nolint:errcheck
}