package handler

import (
	"bytes"
	"encoding/json"
	"strconv"

	"github.com/gin-gonic/gin"

	"apskel-pos-be/internal/constants"
	"apskel-pos-be/internal/contract"
	"apskel-pos-be/internal/models"
	"apskel-pos-be/internal/service"
	"apskel-pos-be/internal/util"
)

// EnakGameCustomerHandler serves /customer/enakgame (docs/rfc-enakgame.md §11).
type EnakGameCustomerHandler struct {
	service service.EnakGameCustomerService
}

func NewEnakGameCustomerHandler(s service.EnakGameCustomerService) *EnakGameCustomerHandler {
	return &EnakGameCustomerHandler{service: s}
}

// ListGames is GET /customer/enakgame/games.
func (h *EnakGameCustomerHandler) ListGames(c *gin.Context) {
	const method = "EnakGameCustomerHandler::ListGames"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.ListGames(c.Request.Context(), customerID), method)
}

// StartSession is POST /customer/enakgame/sessions. It requires Idempotency-Key.
func (h *EnakGameCustomerHandler) StartSession(c *gin.Context) {
	const method = "EnakGameCustomerHandler::StartSession"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	var req contract.StartGameSessionRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		util.HandleResponse(c.Writer, c.Request, contract.BuildErrorResponse([]*contract.ResponseError{
			contract.NewResponseError(constants.MissingFieldErrorCode, constants.RequestEntity, "game_id is required"),
		}), method)
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.StartSession(c.Request.Context(), customerID, &req, idempotencyKey(c)), method)
}

// ListSessions is GET /customer/enakgame/sessions?game_id=&status=&page=&limit=.
func (h *EnakGameCustomerHandler) ListSessions(c *gin.Context) {
	const method = "EnakGameCustomerHandler::ListSessions"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	var q models.GameSessionListQuery
	if !bindQuery(c, &q, method) {
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.ListSessions(c.Request.Context(), customerID, q), method)
}

// GetSession is GET /customer/enakgame/sessions/:id.
func (h *EnakGameCustomerHandler) GetSession(c *gin.Context) {
	const method = "EnakGameCustomerHandler::GetSession"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	id, ok := pathID(c, "id", method)
	if !ok {
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.GetSession(c.Request.Context(), customerID, id), method)
}

// CompleteSession is POST /customer/enakgame/sessions/:id/complete. The body is read
// leniently on purpose: a reward amount, or anything else the backend does not take
// from the client, is ignored rather than refused (P1). An empty body is a result
// with nothing in it.
func (h *EnakGameCustomerHandler) CompleteSession(c *gin.Context) {
	const method = "EnakGameCustomerHandler::CompleteSession"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	id, ok := pathID(c, "id", method)
	if !ok {
		return
	}
	body, ok := rawBody(c, method)
	if !ok {
		return
	}
	var in models.GameSessionCompleteInput
	if len(bytes.TrimSpace(body)) > 0 {
		if err := json.Unmarshal(body, &in); err != nil {
			util.HandleResponse(c.Writer, c.Request, contract.BuildErrorResponse([]*contract.ResponseError{
				contract.NewResponseError(constants.MalformedFieldErrorCode, constants.RequestEntity, "score must be a whole number and outcome a text"),
			}), method)
			return
		}
	}
	util.HandleResponse(c.Writer, c.Request, h.service.CompleteSession(c.Request.Context(), customerID, id, in), method)
}

// ListVouchers is GET /customer/vouchers.
func (h *EnakGameCustomerHandler) ListVouchers(c *gin.Context) {
	const method = "EnakGameCustomerHandler::ListVouchers"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.ListVouchers(c.Request.Context(), customerID), method)
}

// RedeemVoucher is POST /customer/vouchers/:id/redeem. It requires the PIN
// and Idempotency-Key; the body holds the PIN, so it is never logged.
func (h *EnakGameCustomerHandler) RedeemVoucher(c *gin.Context) {
	const method = "EnakGameCustomerHandler::RedeemVoucher"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	id, ok := pathID(c, "id", method)
	if !ok {
		return
	}
	var req contract.RedeemVoucherRequest
	if !bindPinRequest(c, &req, method) {
		return
	}
	util.HandleResponse(c.Writer, c.Request, h.service.RedeemVoucher(c.Request.Context(), customerID, id, &req, idempotencyKey(c), pinRequestInfo(c)), method)
}

// ListRedemptions is GET /customer/vouchers/redemptions?page=&limit=.
func (h *EnakGameCustomerHandler) ListRedemptions(c *gin.Context) {
	const method = "EnakGameCustomerHandler::ListRedemptions"
	customerID, ok := customerIDFromGin(c, method)
	if !ok {
		return
	}
	page, _ := strconv.Atoi(c.Query("page"))
	limit, _ := strconv.Atoi(c.Query("limit"))
	util.HandleResponse(c.Writer, c.Request, h.service.ListRedemptions(c.Request.Context(), customerID, page, limit), method)
}