package handlers

import (
	"encoding/json"
	"log"
	"net/http"

	"github.com/gorilla/mux"
	gorillaWs "github.com/gorilla/websocket"

	"github.com/frisbee-tournament/backend/internal/models"
	"github.com/frisbee-tournament/backend/internal/storage"
	ws "github.com/frisbee-tournament/backend/internal/websocket"
)

type Handler struct {
	store   *storage.Store
	hubMgr  *ws.HubManager
}

func New(store *storage.Store, hubMgr *ws.HubManager) *Handler {
	return &Handler{store: store, hubMgr: hubMgr}
}

var upgrader = gorillaWs.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin: func(r *http.Request) bool {
		return true // trust-based, no auth
	},
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}

// --- Tournament endpoints ---

func (h *Handler) ListTournaments(w http.ResponseWriter, r *http.Request) {
	ts, err := h.store.GetTournaments()
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	writeJSON(w, 200, ts)
}

func (h *Handler) GetTournament(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	t, err := h.store.GetTournament(id)
	if err != nil {
		writeError(w, 404, err.Error())
		return
	}
	writeJSON(w, 200, t)
}

// --- Schedule ---

func (h *Handler) GetSchedule(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	sched, err := h.store.GetSchedule(id)
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	// Merge persisted scores into schedule games
	for i := range sched.Games {
		g := &sched.Games[i]
		state, err := h.store.GetScore(id, g.ID)
		if err == nil && state.Status != "" {
			g.HomeScore = state.HomeScore
			g.AwayScore = state.AwayScore
			g.Status = state.Status
		}
	}
	writeJSON(w, 200, sched)
}

// --- Scoring ---

func (h *Handler) GetScore(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	state, err := h.store.GetScore(vars["id"], vars["gid"])
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	writeJSON(w, 200, state)
}

func (h *Handler) UpdateScore(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	var update models.ScoreUpdate
	if err := json.NewDecoder(r.Body).Decode(&update); err != nil {
		writeError(w, 400, "invalid request body")
		return
	}
	hub := h.hubMgr.GetOrCreateHub(vars["id"], vars["gid"])
	state, err := hub.HandleScoreUpdate(update)
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	writeJSON(w, 200, state)
}

func (h *Handler) GetAuditLog(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	entries, err := h.store.GetAuditLog(vars["id"], vars["gid"])
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	if entries == nil {
		entries = []models.AuditEntry{}
	}
	writeJSON(w, 200, entries)
}

// --- WebSocket ---

func (h *Handler) WebSocketHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("ws upgrade error: %v", err)
		return
	}
	userID := r.URL.Query().Get("user_id")
	if userID == "" {
		userID = "anonymous"
	}
	hub := h.hubMgr.GetOrCreateHub(vars["id"], vars["gid"])
	client := hub.RegisterClient(conn, userID)
	go client.WritePump()
	go client.ReadPump()
}

func (h *Handler) TournamentWebSocketHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("ws upgrade error: %v", err)
		return
	}
	th := h.hubMgr.GetOrCreateTournamentHub(vars["id"])
	client := th.RegisterClient(conn)
	go client.WritePump()
	go client.ReadPumpTournament(th)
}

// --- Questionnaire ---

func (h *Handler) GetQuestionnaire(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	cfg, err := h.store.GetQuestionnaireConfig(id)
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	t, _ := h.store.GetTournament(id)
	resp := map[string]any{
		"config": cfg,
	}
	if t != nil {
		resp["teams"] = t.Teams
	}
	writeJSON(w, 200, resp)
}

func (h *Handler) SubmitQuestionnaire(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	var resp models.QuestionnaireResponse
	if err := json.NewDecoder(r.Body).Decode(&resp); err != nil {
		writeError(w, 400, "invalid request body")
		return
	}
	resp.TourneyID = id
	if err := h.store.SaveQuestionnaireResponse(id, &resp); err != nil {
		writeError(w, 500, err.Error())
		return
	}
	writeJSON(w, 201, map[string]string{"status": "ok", "id": resp.ID})
}

func (h *Handler) GetQuestionnaireResults(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	resps, err := h.store.GetQuestionnaireResponses(id)
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	if resps == nil {
		resps = []models.QuestionnaireResponse{}
	}
	writeJSON(w, 200, resps)
}

// --- Results ---

func (h *Handler) GetResults(w http.ResponseWriter, r *http.Request) {
	id := mux.Vars(r)["id"]
	res, err := h.store.GetResults(id)
	if err != nil {
		writeError(w, 500, err.Error())
		return
	}
	writeJSON(w, 200, res)
}