namespace WxAgent.Core;

public static class WechatDerivedText
{
    // Only consume new text inside the bound message, never an entire window or an unbound OCR popup.
    public static string? AddedText(IReadOnlyList<string> before, IReadOnlyList<string> after)
    {
        var remaining = before.Where(value => !string.IsNullOrWhiteSpace(value))
            .GroupBy(value => value, StringComparer.Ordinal).ToDictionary(group => group.Key, group => group.Count(), StringComparer.Ordinal);
        var added = new List<string>();
        foreach (var value in after.Where(value => !string.IsNullOrWhiteSpace(value)))
        {
            if (remaining.GetValueOrDefault(value) > 0) remaining[value]--;
            else added.Add(value);
        }
        if (remaining.Values.Any(count => count > 0) || added.Count == 0) return null;
        if (added.Any(value => value.Contains("识别中", StringComparison.Ordinal) || value.Contains("转换中", StringComparison.Ordinal)
            || value.Contains("转换失败", StringComparison.Ordinal) || value.Contains("识别失败", StringComparison.Ordinal)
            || value.Contains("未识别到", StringComparison.Ordinal) || value.Contains("无法转换", StringComparison.Ordinal))) return null;
        return string.Join(Environment.NewLine, added);
    }
}