package checker

import (
	"context"
	"errors"
	"fmt"
	"strconv"

	"github.com/samber/lo"
	"google.golang.org/grpc"
	"gorm.io/gorm"

	"github.com/tidbcloud/tidb-management-service/tidb-mgmt-service/pkg/apimiddleware/bizerror"
	"github.com/tidbcloud/tidb-management-service/utilities/bizerr"
	"github.com/tidbcloud/tidb-management-service/utilities/grpc/metadata"
)

// StdTidbIdExtractor extracts tidb_id from requests that implement GetTidbId() directly.
func StdTidbIdExtractor(req any) (string, error) {
	type tidbRequest interface{ GetTidbId() string }
	r, ok := req.(tidbRequest)
	if !ok {
		return "", bizerr.New(bizerr.ErrCodeParams, "invalid request: req=%v", req)
	}
	return r.GetTidbId(), nil
}

// NewTidbPermissionChecker creates a permission checker that validates the requesting user
// owns the TiDB instance. The extractTidbId function extracts the tidb ID string from the
// request — callers MUST provide an appropriate extractor for each method registered in the
// interceptor, so new APIs cannot silently skip permission checks.
func NewTidbPermissionChecker(extractTidbId func(req any) (string, error)) CheckFunc {
	return func(
		ctx context.Context,
		checkCtx *CheckContext,
		req any,
		info *grpc.UnaryServerInfo,
	) (context.Context, any, error) {
		reqMeta, err := metadata.ExtractRequestMeta(ctx)
		if err != nil {
			return ctx, req, bizerror.NewInternal(err, "failed to extract request meta")
		}

		tidbIdStr, err := extractTidbId(req)
		if err != nil {
			return ctx, req, err
		}

		tidbId, err := strconv.ParseUint(tidbIdStr, 10, 64)
		if err != nil {
			return ctx, req, bizerr.WrapErrorWithCode(err, bizerr.ErrCodeParams, "invalid tidb id: %s", tidbIdStr)
		}

		tidbCluster, err := checkCtx.ClusterRepo.GetCluster(ctx, tidbId, true)
		if err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return ctx, req, bizerror.NewNotFound(err, fmt.Sprintf("tidb %d not found", tidbId))
			}
			return ctx, req, bizerror.NewInternal(err, "failed to get tidb")
		}

		if tidbCluster.OrganizationId != reqMeta.OrgID {
			return ctx, req, bizerr.New(bizerr.ErrCodePermission, bizerr.ErrMsgResourceNoPermission)
		}

		reqMeta.ClusterID = tidbId
		reqMeta.IsCheckPermission = lo.ToPtr(true)

		return metadata.AppendToIncomingMeta(ctx, reqMeta), req, nil
	}
}