using GameList.Contracts;

namespace GameList.Endpoints;

internal static class SuggestionValidator
{
    public static async Task<string?> ValidateAsync(SuggestionRequest request, IHttpClientFactory httpFactory)
    {
        if (string.IsNullOrWhiteSpace(request.Name) || request.Name.Length > 100)
            return "Name is required and must be <= 100 characters.";

        if (!EndpointHelpers.IsValidImageUrl(request.ScreenshotUrl))
            return "Screenshot URL must be http(s) and end with an image file extension.";

        if (!await EndpointHelpers.IsReachableImageAsync(request.ScreenshotUrl, httpFactory))
            return "Screenshot URL could not be validated as an image. Use a public image link (http/https, no redirects, max 5 MB).";

        if (!EndpointHelpers.IsValidHttpUrl(request.GameUrl))
            return "Game URL must be http or https.";

        if (!EndpointHelpers.IsValidHttpUrl(request.YoutubeUrl))
            return "YouTube URL must be http or https.";

        return ValidatePlayers(request.MinPlayers, request.MaxPlayers);
    }

    private static string? ValidatePlayers(int? minPlayers, int? maxPlayers)
    {
        if (minPlayers is null && maxPlayers is null)
            return null;

        if (minPlayers is < 1 or > 32)
            return "Min players must be between 1 and 32.";

        if (maxPlayers is < 1 or > 32)
            return "Max players must be between 1 and 32.";

        if (minPlayers is null || maxPlayers is null)
            return "Provide both min and max players.";

        if (minPlayers > maxPlayers)
            return "Min players cannot exceed max players.";

        return null;
    }
}