package im

import (
	"net/http"
	"strconv"
	"strings"

	"github.com/tidbcloud/AgentTeam/internal/api"
)

const (
	defaultIMListLimit = 50
	maxIMListLimit     = 100
)

func parseLimit(raw string, defaultLimit int, maxLimit int) (int, error) {
	trimmed := strings.TrimSpace(raw)
	if trimmed == "" {
		return defaultLimit, nil
	}
	limit, err := strconv.Atoi(trimmed)
	if err != nil || limit <= 0 {
		return 0, api.NewHTTPError(http.StatusBadRequest, "limit must be a positive integer")
	}
	if limit > maxLimit {
		return maxLimit, nil
	}
	return limit, nil
}

func parseOptionalInt64(raw string, name string) (*int64, error) {
	trimmed := strings.TrimSpace(raw)
	if trimmed == "" {
		return nil, nil
	}
	value, err := strconv.ParseInt(trimmed, 10, 64)
	if err != nil || value < 0 {
		return nil, api.NewHTTPError(http.StatusBadRequest, name+" must be a non-negative integer")
	}
	return &value, nil
}