package routes

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

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

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

// TournamentHandler handles tournament lifecycle, state, and deal API routes.
type TournamentHandler struct {
	service *tournament.Service
	multi   *tournament.MultiManager
	chop    *financial.ChopEngine
}

// NewTournamentHandler creates a new tournament route handler.
func NewTournamentHandler(
	service *tournament.Service,
	multi *tournament.MultiManager,
	chop *financial.ChopEngine,
) *TournamentHandler {
	return &TournamentHandler{
		service: service,
		multi:   multi,
		chop:    chop,
	}
}

// RegisterRoutes registers tournament routes on the given router.
func (h *TournamentHandler) RegisterRoutes(r chi.Router) {
	r.Route("/tournaments", func(r chi.Router) {
		// Read-only (any authenticated user)
		r.Get("/", h.handleListTournaments)
		r.Get("/active", h.handleListActive)

		// Mutations (admin role for create)
		r.Group(func(r chi.Router) {
			r.Use(middleware.RequireRole(middleware.RoleAdmin))
			r.Post("/", h.handleCreateFromTemplate)
			r.Post("/manual", h.handleCreateManual)
		})

		// Tournament-scoped routes
		r.Route("/{id}", func(r chi.Router) {
			// Read-only
			r.Get("/", h.handleGetTournament)
			r.Get("/state", h.handleGetState)
			r.Get("/activity", h.handleGetActivity)

			// Deal/chop read-only
			r.Get("/deal/proposals", h.handleListDealProposals)

			// Mutations (floor or admin)
			r.Group(func(r chi.Router) {
				r.Use(middleware.RequireRole(middleware.RoleFloor))
				r.Post("/start", h.handleStart)
				r.Post("/pause", h.handlePause)
				r.Post("/resume", h.handleResume)
				r.Post("/cancel", h.handleCancel)

				// Deal/chop mutations
				r.Post("/deal/propose", h.handleProposeDeal)
				r.Post("/deal/proposals/{proposalId}/confirm", h.handleConfirmDeal)
				r.Post("/deal/proposals/{proposalId}/cancel", h.handleCancelDeal)
			})
		})
	})
}

// ---------- Tournament CRUD ----------

type createFromTemplateRequest struct {
	TemplateID int64                          `json:"template_id"`
	Name       string                         `json:"name,omitempty"`
	Overrides  tournament.TournamentOverrides  `json:"overrides"`
}

func (h *TournamentHandler) handleCreateFromTemplate(w http.ResponseWriter, r *http.Request) {
	var req createFromTemplateRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
		return
	}

	if req.TemplateID == 0 {
		writeError(w, http.StatusBadRequest, "template_id is required")
		return
	}

	// Allow name at top level or in overrides
	if req.Name != "" && req.Overrides.Name == "" {
		req.Overrides.Name = req.Name
	}

	t, err := h.service.CreateFromTemplate(r.Context(), req.TemplateID, req.Overrides)
	if err != nil {
		status := http.StatusBadRequest
		if err == tournament.ErrTemplateNotFound {
			status = http.StatusNotFound
		}
		writeError(w, status, err.Error())
		return
	}

	writeJSON(w, http.StatusCreated, t)
}

func (h *TournamentHandler) handleCreateManual(w http.ResponseWriter, r *http.Request) {
	var config tournament.TournamentConfig
	if err := json.NewDecoder(r.Body).Decode(&config); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
		return
	}

	t, err := h.service.CreateManual(r.Context(), config)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusCreated, t)
}

func (h *TournamentHandler) handleListTournaments(w http.ResponseWriter, r *http.Request) {
	summaries, err := h.multi.ListAllTournaments(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, summaries)
}

func (h *TournamentHandler) handleListActive(w http.ResponseWriter, r *http.Request) {
	summaries, err := h.multi.ListActiveTournaments(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, summaries)
}

func (h *TournamentHandler) handleGetTournament(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	detail, err := h.service.GetTournament(r.Context(), id)
	if err != nil {
		if err == tournament.ErrTournamentNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, detail)
}

func (h *TournamentHandler) handleGetState(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	state, err := h.service.GetTournamentState(r.Context(), id)
	if err != nil {
		if err == tournament.ErrTournamentNotFound {
			writeError(w, http.StatusNotFound, err.Error())
			return
		}
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, state)
}

func (h *TournamentHandler) handleGetActivity(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	limitStr := r.URL.Query().Get("limit")
	limit := 20
	if limitStr != "" {
		if v, err := strconv.Atoi(limitStr); err == nil && v > 0 && v <= 100 {
			limit = v
		}
	}

	activity := h.service.BuildActivityFeed(r.Context(), id, limit)
	writeJSON(w, http.StatusOK, map[string]interface{}{
		"activity": activity,
	})
}

// ---------- Tournament Lifecycle ----------

func (h *TournamentHandler) handleStart(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.service.StartTournament(r.Context(), id); err != nil {
		status := http.StatusBadRequest
		if err == tournament.ErrTournamentNotFound {
			status = http.StatusNotFound
		}
		writeError(w, status, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "started"})
}

func (h *TournamentHandler) handlePause(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.service.PauseTournament(r.Context(), id); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "paused"})
}

func (h *TournamentHandler) handleResume(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.service.ResumeTournament(r.Context(), id); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "resumed"})
}

func (h *TournamentHandler) handleCancel(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if err := h.service.CancelTournament(r.Context(), id); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "cancelled"})
}

// ---------- Deal/Chop Routes ----------

type proposeDealRequest struct {
	Type         string           `json:"type"` // icm, chip_chop, even_chop, custom, partial_chop
	PlayerStacks map[string]int64 `json:"stacks,omitempty"`
	CustomAmounts map[string]int64 `json:"custom_amounts,omitempty"`
	PartialPool   int64            `json:"partial_pool,omitempty"`
	RemainingPool int64            `json:"remaining_pool,omitempty"`
}

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

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

	if h.chop == nil {
		writeError(w, http.StatusInternalServerError, "chop engine not available")
		return
	}

	params := financial.DealParams{
		PlayerStacks:  req.PlayerStacks,
		CustomAmounts: req.CustomAmounts,
		PartialPool:   req.PartialPool,
		RemainingPool: req.RemainingPool,
	}

	proposal, err := h.chop.ProposeDeal(r.Context(), id, req.Type, params)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, proposal)
}

func (h *TournamentHandler) handleConfirmDeal(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	proposalID := chi.URLParam(r, "proposalId")

	if h.chop == nil {
		writeError(w, http.StatusInternalServerError, "chop engine not available")
		return
	}

	if err := h.chop.ConfirmDeal(r.Context(), id, proposalID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

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

func (h *TournamentHandler) handleCancelDeal(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	proposalID := chi.URLParam(r, "proposalId")

	if h.chop == nil {
		writeError(w, http.StatusInternalServerError, "chop engine not available")
		return
	}

	if err := h.chop.CancelDeal(r.Context(), id, proposalID); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

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

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

	if h.chop == nil {
		writeJSON(w, http.StatusOK, []interface{}{})
		return
	}

	proposals, err := h.chop.ListProposals(r.Context(), id)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, proposals)
}