namespace Service.IconSearch;

/// <summary>
/// Iconify API 响应
/// 实际 API 返回的图标是字符串数组，格式为 "collection:iconName"
/// 例如：["mdi:home", "svg-spinners:wind-toy"]
/// </summary>
public record IconifyApiResponse
{
    [JsonPropertyName("icons")]
    public List<string>? Icons { get; init; }
}

public record IconifySettings
{
    public string ApiUrl { get; init; } = "https://api.iconify.design/search";
    public int DefaultLimit { get; init; } = 20;
    public int MaxRetryCount { get; init; } = 3;
    public int RetryDelayMs { get; init; } = 1000;
}

public class IconifyApiService(
    IOptions<IconifySettings> settings,
    ILogger<IconifyApiService> logger
) : IIconifyApiService
{
    private readonly HttpClient _httpClient = new();
    private readonly IconifySettings _settings = settings.Value;

    public async Task<List<IconCandidate>> SearchIconsAsync(List<string> keywords, int limit = 20)
    {
        var allIcons = new List<IconCandidate>();
        var actualLimit = limit > 0 ? limit : _settings.DefaultLimit;

        foreach (var keyword in keywords)
        {
            try
            {
                var icons = await SearchIconsByKeywordAsync(keyword, actualLimit);
                allIcons.AddRange(icons);
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "搜索图标失败，关键字：{Keyword}", keyword);
            }
        }

        return allIcons;
    }

    private async Task<List<IconCandidate>> SearchIconsByKeywordAsync(string keyword, int limit)
    {
        var url = $"{_settings.ApiUrl}?query={Uri.EscapeDataString(keyword)}&limit={limit}";
        var response = await CallApiWithRetryAsync(url);

        if (string.IsNullOrEmpty(response))
        {
            return [];
        }

        var apiResponse = JsonSerializer.Deserialize<IconifyApiResponse>(response);
        if (apiResponse?.Icons == null)
        {
            return [];
        }

        // 解析字符串格式 "collection:iconName" 为 IconCandidate
        var candidates = apiResponse.Icons
            .Select(iconStr =>
            {
                var parts = iconStr.Split(':', 2);
                if (parts.Length != 2)
                {
                    logger.LogWarning("无效的图标标识符格式：{IconStr}", iconStr);
                    return null;
                }

                return new IconCandidate
                {
                    CollectionName = parts[0],
                    IconName = parts[1]
                };
            })
            .Where(c => c != null)
            .Cast<IconCandidate>()
            .ToList();

        return candidates;
    }

    private async Task<string> CallApiWithRetryAsync(string url)
    {
        var retryCount = 0;
        var delay = _settings.RetryDelayMs;

        while (retryCount < _settings.MaxRetryCount)
        {
            try
            {
                var response = await _httpClient.GetAsync(url);
                response.EnsureSuccessStatusCode();

                return await response.Content.ReadAsStringAsync();
            }
            catch (HttpRequestException ex) when (retryCount < _settings.MaxRetryCount - 1)
            {
                logger.LogWarning(ex, "Iconify API调用失败，等待 {DelayMs}ms 后重试（{RetryCount}/{MaxRetryCount}）",
                    delay, retryCount + 1, _settings.MaxRetryCount);
                await Task.Delay(delay);
                delay *= 2;
                retryCount++;
            }
        }

        throw new HttpRequestException($"Iconify API调用失败，已重试 {_settings.MaxRetryCount} 次");
    }
}