package routes

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

	"github.com/go-chi/chi/v5"

	"github.com/felt-app/felt/internal/financial"
	"github.com/felt-app/felt/internal/player"
	"github.com/felt-app/felt/internal/seating"
	"github.com/felt-app/felt/internal/server/middleware"
)

// PlayerHandler handles player and tournament player API routes.
type PlayerHandler struct {
	players   *player.Service
	ranking   *player.RankingEngine
	financial *financial.Engine
	tables    *seating.TableService
}

// NewPlayerHandler creates a new player route handler.
func NewPlayerHandler(
	players *player.Service,
	ranking *player.RankingEngine,
	fin *financial.Engine,
	tables *seating.TableService,
) *PlayerHandler {
	return &PlayerHandler{
		players:   players,
		ranking:   ranking,
		financial: fin,
		tables:    tables,
	}
}

// RegisterRoutes registers player routes on the given router.
func (h *PlayerHandler) RegisterRoutes(r chi.Router) {
	// Venue-level player routes
	r.Route("/players", func(r chi.Router) {
		r.Get("/", h.handleListPlayers)
		r.Get("/search", h.handleSearchPlayers)
		r.Post("/", h.handleCreatePlayer)
		r.Get("/{id}", h.handleGetPlayer)
		r.Put("/{id}", h.handleUpdatePlayer)
		r.Get("/{id}/qrcode", h.handleGetQRCode)

		// Admin-only operations
		r.Group(func(r chi.Router) {
			r.Use(middleware.RequireRole(middleware.RoleAdmin))
			r.Post("/merge", h.handleMergePlayers)
			r.Post("/import", h.handleImportCSV)
		})
	})

	// Tournament-scoped player routes
	r.Route("/tournaments/{id}", func(r chi.Router) {
		// Read-only (any authenticated user)
		r.Get("/players", h.handleGetTournamentPlayers)
		r.Get("/players/{playerId}", h.handleGetTournamentPlayer)
		r.Get("/rankings", h.handleGetRankings)

		// Mutation routes (floor or admin)
		r.Group(func(r chi.Router) {
			r.Use(middleware.RequireRole(middleware.RoleFloor))

			// Player actions
			r.Post("/players/{playerId}/buyin", h.handleBuyIn)
			r.Post("/players/{playerId}/bust", h.handleBust)
			r.Post("/players/{playerId}/rebuy", h.handleRebuy)
			r.Post("/players/{playerId}/addon", h.handleAddOn)
			r.Post("/players/{playerId}/reentry", h.handleReEntry)
			r.Post("/players/{playerId}/undo-bust", h.handleUndoBust)

			// Transaction undo
			r.Post("/transactions/{txId}/undo", h.handleUndoTransaction)
		})
	})
}

// ---------- Venue-level Player Handlers ----------

func (h *PlayerHandler) handleListPlayers(w http.ResponseWriter, r *http.Request) {
	limit := queryInt(r, "limit", 50)
	offset := queryInt(r, "offset", 0)

	players, err := h.players.ListPlayers(r.Context(), limit, offset)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, players)
}

func (h *PlayerHandler) handleSearchPlayers(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query().Get("q")
	limit := queryInt(r, "limit", 20)

	players, err := h.players.SearchPlayers(r.Context(), query, limit)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, players)
}

type createPlayerRequest struct {
	Name     string  `json:"name"`
	Nickname *string `json:"nickname,omitempty"`
	Email    *string `json:"email,omitempty"`
	Phone    *string `json:"phone,omitempty"`
	Notes    *string `json:"notes,omitempty"`
}

func (h *PlayerHandler) handleCreatePlayer(w http.ResponseWriter, r *http.Request) {
	var req createPlayerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
		return
	}
	if req.Name == "" {
		writeError(w, http.StatusBadRequest, "name is required")
		return
	}

	p := player.Player{
		Name:     req.Name,
		Nickname: req.Nickname,
		Email:    req.Email,
		Phone:    req.Phone,
		Notes:    req.Notes,
	}

	created, err := h.players.CreatePlayer(r.Context(), p)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, created)
}

func (h *PlayerHandler) handleGetPlayer(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	p, err := h.players.GetPlayer(r.Context(), id)
	if err != nil {
		if err == player.ErrPlayerNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, p)
}

func (h *PlayerHandler) handleUpdatePlayer(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")

	var req createPlayerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
		return
	}
	if req.Name == "" {
		writeError(w, http.StatusBadRequest, "name is required")
		return
	}

	p := player.Player{
		ID:       id,
		Name:     req.Name,
		Nickname: req.Nickname,
		Email:    req.Email,
		Phone:    req.Phone,
		Notes:    req.Notes,
	}

	if err := h.players.UpdatePlayer(r.Context(), p); err != nil {
		if err == player.ErrPlayerNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "updated"})
}

func (h *PlayerHandler) handleGetQRCode(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	png, err := h.players.GenerateQRCode(r.Context(), id)
	if err != nil {
		if err == player.ErrPlayerNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	w.Header().Set("Content-Type", "image/png")
	w.Header().Set("Cache-Control", "public, max-age=86400")
	w.WriteHeader(http.StatusOK)
	w.Write(png)
}

type mergePlayersRequest struct {
	KeepID  string `json:"keep_id"`
	MergeID string `json:"merge_id"`
}

func (h *PlayerHandler) handleMergePlayers(w http.ResponseWriter, r *http.Request) {
	var req mergePlayersRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
		return
	}
	if req.KeepID == "" || req.MergeID == "" {
		writeError(w, http.StatusBadRequest, "keep_id and merge_id are required")
		return
	}
	if req.KeepID == req.MergeID {
		writeError(w, http.StatusBadRequest, "keep_id and merge_id must be different")
		return
	}

	if err := h.players.MergePlayers(r.Context(), req.KeepID, req.MergeID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "merged"})
}

func (h *PlayerHandler) handleImportCSV(w http.ResponseWriter, r *http.Request) {
	// Parse multipart form with 5MB limit
	if err := r.ParseMultipartForm(5 << 20); err != nil {
		writeError(w, http.StatusBadRequest, "invalid multipart form: "+err.Error())
		return
	}

	file, _, err := r.FormFile("file")
	if err != nil {
		writeError(w, http.StatusBadRequest, "file upload required: "+err.Error())
		return
	}
	defer file.Close()

	result, err := h.players.ImportFromCSV(r.Context(), file)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, result)
}

// ---------- Tournament Player Handlers ----------

func (h *PlayerHandler) handleGetTournamentPlayers(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	players, err := h.players.GetTournamentPlayers(r.Context(), tournamentID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, players)
}

func (h *PlayerHandler) handleGetTournamentPlayer(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	detail, err := h.players.GetTournamentPlayer(r.Context(), tournamentID, playerID)
	if err != nil {
		if err == player.ErrPlayerNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, detail)
}

func (h *PlayerHandler) handleGetRankings(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	rankings, err := h.ranking.GetRankings(r.Context(), tournamentID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]interface{}{
		"rankings": rankings,
	})
}

// ---------- Buy-in / Bust / Rebuy / Addon / Re-entry Handlers ----------

type buyInRequest struct {
	Override bool `json:"override,omitempty"`
}

func (h *PlayerHandler) handleBuyIn(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	var req buyInRequest
	// Body is optional
	json.NewDecoder(r.Body).Decode(&req)

	// Register player if not already in tournament
	_, err := h.players.GetTournamentPlayer(r.Context(), tournamentID, playerID)
	if err == player.ErrPlayerNotFound {
		// Auto-register
		_, regErr := h.players.RegisterPlayer(r.Context(), tournamentID, playerID)
		if regErr != nil {
			writeError(w, http.StatusBadRequest, regErr.Error())
			return
		}
	} else if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	// Process buy-in via financial engine
	tx, err := h.financial.ProcessBuyIn(r.Context(), tournamentID, playerID, req.Override)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	// Auto-seat suggestion
	var seatAssignment *seating.SeatAssignment
	if h.tables != nil {
		assignment, seatErr := h.tables.AutoAssignSeat(r.Context(), tournamentID, playerID)
		if seatErr == nil {
			seatAssignment = assignment
		}
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"transaction":     tx,
		"seat_suggestion": seatAssignment,
	})
}

type bustRequest struct {
	HitmanPlayerID *string `json:"hitman_player_id,omitempty"`
}

func (h *PlayerHandler) handleBust(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	var req bustRequest
	json.NewDecoder(r.Body).Decode(&req)

	if err := h.players.BustPlayer(r.Context(), tournamentID, playerID, req.HitmanPlayerID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	// Get updated rankings
	rankings, err := h.ranking.GetRankings(r.Context(), tournamentID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"status":   "busted",
		"rankings": rankings,
	})
}

func (h *PlayerHandler) handleRebuy(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	tx, err := h.financial.ProcessRebuy(r.Context(), tournamentID, playerID)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, tx)
}

func (h *PlayerHandler) handleAddOn(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	tx, err := h.financial.ProcessAddOn(r.Context(), tournamentID, playerID)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, tx)
}

func (h *PlayerHandler) handleReEntry(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	tx, err := h.financial.ProcessReEntry(r.Context(), tournamentID, playerID)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	// Auto-seat for re-entry
	var seatAssignment *seating.SeatAssignment
	if h.tables != nil {
		assignment, seatErr := h.tables.AutoAssignSeat(r.Context(), tournamentID, playerID)
		if seatErr == nil {
			seatAssignment = assignment
		}
	}

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"transaction":     tx,
		"seat_suggestion": seatAssignment,
	})
}

func (h *PlayerHandler) handleUndoBust(w http.ResponseWriter, r *http.Request) {
	tournamentID := chi.URLParam(r, "id")
	playerID := chi.URLParam(r, "playerId")

	if err := h.players.UndoBust(r.Context(), tournamentID, playerID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	// Get updated rankings
	rankings, _ := h.ranking.GetRankings(r.Context(), tournamentID)

	writeJSON(w, http.StatusOK, map[string]interface{}{
		"status":   "undo_bust",
		"rankings": rankings,
	})
}

func (h *PlayerHandler) handleUndoTransaction(w http.ResponseWriter, r *http.Request) {
	txID := chi.URLParam(r, "txId")

	if err := h.financial.UndoTransaction(r.Context(), txID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]string{"status": "undone"})
}

// ---------- Helpers ----------

func queryInt(r *http.Request, key string, defaultVal int) int {
	v := r.URL.Query().Get(key)
	if v == "" {
		return defaultVal
	}
	n := 0
	for _, c := range v {
		if c < '0' || c > '9' {
			return defaultVal
		}
		n = n*10 + int(c-'0')
	}
	if n <= 0 {
		return defaultVal
	}
	return n
}