package app

import (
	"context"
	"io"
	"log"
	"net/http"
	"strconv"
	"strings"

	"evening_detective_server/internal/modules/processor_jwt"
	"evening_detective_server/internal/modules/roles"
	"evening_detective_server/internal/services/game_export_service"
	"evening_detective_server/proto"
	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

func canExportGame(claims *processor_jwt.JWTClaims) bool {
	return claims != nil && (roles.HasRole(claims, roles.Organizer) || claims.HasRole(roles.Developer))
}

func (s *server) StartGameExport(ctx context.Context, req *proto.StartGameExportReq) (*proto.GameExportRsp, error) {
	claims, err := claimsFromContext(ctx)
	if err != nil {
		return nil, err
	}
	if !canExportGame(claims) {
		return nil, status.Error(codes.PermissionDenied, "permission denied")
	}
	result, err := s.gameExportService.Start(ctx, int(req.GetID()), claims.UserID)
	if err != nil {
		return nil, gameExportErrorStatus(err)
	}
	return &proto.GameExportRsp{Export: mapGameExport(result)}, nil
}

func (s *server) GetGameExport(ctx context.Context, req *proto.GetGameExportReq) (*proto.GameExportRsp, error) {
	claims, err := claimsFromContext(ctx)
	if err != nil {
		return nil, err
	}
	if !canExportGame(claims) {
		return nil, status.Error(codes.PermissionDenied, "permission denied")
	}
	result, err := s.gameExportService.Get(ctx, int(req.GetID()))
	if err != nil {
		return nil, gameExportErrorStatus(err)
	}
	return &proto.GameExportRsp{Export: mapGameExport(result)}, nil
}

func (s *server) ResetGameLocalMode(ctx context.Context, req *proto.ResetGameLocalModeReq) (*proto.ResetGameLocalModeRsp, error) {
	claims, err := claimsFromContext(ctx)
	if err != nil {
		return nil, err
	}
	if !canExportGame(claims) {
		return nil, status.Error(codes.PermissionDenied, "permission denied")
	}
	if err := s.gameExportService.ResetLocalMode(ctx, int(req.GetID()), req.GetExportID()); err != nil {
		return nil, gameExportErrorStatus(err)
	}
	return &proto.ResetGameLocalModeRsp{}, nil
}

// GameExportDownloadHandler authenticates with the existing JWT processor and streams private ZIPs.
func GameExportDownloadHandler(jwt processor_jwt.IProcessorJWT, exports *game_export_service.GameExportService) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Cache-Control", "no-store")
		fail := func(err error) {
			w.Header().Set("Content-Type", "application/json")
			w.WriteHeader(runtime.HTTPStatusFromCode(status.Code(err)))
			// The message has already been reduced to a safe transport error.
			_, _ = w.Write([]byte(`{"error":` + strconv.Quote(status.Convert(err).Message()) + `}`))
		}
		token := strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")
		if token == "" {
			fail(status.Error(codes.Unauthenticated, "Требуется авторизация"))
			return
		}
		claims, err := jwt.GetClaims(token)
		if err != nil {
			fail(status.Error(codes.Unauthenticated, "Недействительный токен"))
			return
		}
		if !canExportGame(claims) {
			fail(status.Error(codes.PermissionDenied, "permission denied"))
			return
		}
		gameID, err := strconv.ParseInt(r.PathValue("id"), 10, 32)
		if err != nil || gameID <= 0 {
			fail(status.Error(codes.InvalidArgument, "Некорректный идентификатор игры"))
			return
		}
		result, body, err := exports.OpenDownload(r.Context(), int(gameID))
		if err != nil {
			fail(gameExportErrorStatus(err))
			return
		}
		defer func() { _ = body.Close() }()
		w.Header().Set("Content-Type", "application/zip")
		w.Header().Set("Content-Disposition", `attachment; filename="game-`+result.PackageID+`.zip"`)
		w.Header().Set("Content-Length", strconv.FormatInt(result.Size, 10))
		w.Header().Set("X-Content-Type-Options", "nosniff")
		if _, err := io.CopyBuffer(w, body, make([]byte, 32<<10)); err != nil && r.Context().Err() == nil {
			log.Printf("game export download: %v", err)
		}
	})
}