DiscordChatExporter/DiscordChatExporter.Core/Exporting/ExportRequest.cs

using System;
using System.Globalization;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using DiscordChatExporter.Core.Discord;
using DiscordChatExporter.Core.Discord.Data;
using DiscordChatExporter.Core.Exporting.Filtering;
using DiscordChatExporter.Core.Exporting.Partitioning;
using DiscordChatExporter.Core.Utils;
using DiscordChatExporter.Core.Utils.Extensions;

namespace DiscordChatExporter.Core.Exporting;

public partial class ExportRequest
{
    public Guild Guild { get; }

    public Channel Channel { get; }

    public string OutputFilePath { get; }

    public string OutputDirPath { get; }

    public string AssetsDirPath { get; }

    public ExportFormat Format { get; }

    public Snowflake? After { get; }

    public Snowflake? Before { get; }

    public PartitionLimit PartitionLimit { get; }

    public MessageFilter MessageFilter { get; }

    public bool ShouldFormatMarkdown { get; }

    public bool ShouldDownloadAssets { get; }

    public bool ShouldReuseAssets { get; }

    public string? Locale { get; }

    public CultureInfo? CultureInfo { get; }

    public bool IsUtcNormalizationEnabled { get; }

    public ExportRequest(
        Guild guild,
        Channel channel,
        string outputPath,
        string? assetsDirPath,
        ExportFormat format,
        Snowflake? after,
        Snowflake? before,
        PartitionLimit partitionLimit,
        MessageFilter messageFilter,
        bool shouldFormatMarkdown,
        bool shouldDownloadAssets,
        bool shouldReuseAssets,
        string? locale,
        bool isUtcNormalizationEnabled
    )
    {
        Guild = guild;
        Channel = channel;
        Format = format;
        After = after;
        Before = before;
        PartitionLimit = partitionLimit;
        MessageFilter = messageFilter;
        ShouldFormatMarkdown = shouldFormatMarkdown;
        ShouldDownloadAssets = shouldDownloadAssets;
        ShouldReuseAssets = shouldReuseAssets;
        Locale = locale;
        IsUtcNormalizationEnabled = isUtcNormalizationEnabled;

        OutputFilePath = GetOutputBaseFilePath(Guild, Channel, outputPath, Format, After, Before);

        OutputDirPath = Path.GetDirectoryName(OutputFilePath)!;

        AssetsDirPath = !string.IsNullOrWhiteSpace(assetsDirPath)
            ? FormatPath(assetsDirPath, Guild, Channel, After, Before)
            : $"{OutputFilePath}_Files{Path.DirectorySeparatorChar}";

        CultureInfo = Locale?.Pipe(CultureInfo.GetCultureInfo);
    }
}

public partial class ExportRequest
{
    public static string GetDefaultOutputFileName(
        Guild guild,
        Channel channel,
        ExportFormat format,
        Snowflake? after = null,
        Snowflake? before = null
    )
    {
        var buffer = new StringBuilder();

        // Guild name
        buffer.Append(guild.Name);

        // Parent name
        if (channel.Parent is not null)
            buffer.Append(" - ").Append(channel.Parent.Name);

        // Channel name and ID
        buffer
            .Append(" - ")
            .Append(channel.Name)
            .Append(' ')
            .Append('[')
            .Append(channel.Id)
            .Append(']');

        // Date range
        if (after is not null || before is not null)
        {
            buffer.Append(' ').Append('(');

            // Both 'after' and 'before' are set
            if (after is not null && before is not null)
            {
                buffer.Append(
                    $"{after.Value.ToDate():yyyy-MM-dd} to {before.Value.ToDate():yyyy-MM-dd}"
                );
            }
            // Only 'after' is set
            else if (after is not null)
            {
                buffer.Append($"after {after.Value.ToDate():yyyy-MM-dd}");
            }
            // Only 'before' is set
            else if (before is not null)
            {
                buffer.Append($"before {before.Value.ToDate():yyyy-MM-dd}");
            }

            buffer.Append(')');
        }

        // File extension
        buffer.Append('.').Append(format.GetFileExtension());

        return PathEx.EscapeFileName(buffer.ToString());
    }

    private static string FormatPath(
        string path,
        Guild guild,
        Channel channel,
        Snowflake? after,
        Snowflake? before
    ) =>
        Regex.Replace(
            path,
            "%.",
            m =>
                PathEx.EscapeFileName(
                    m.Value switch
                    {
                        "%g" => guild.Id.ToString(),
                        "%G" => guild.Name,

                        "%t" => channel.Parent?.Id.ToString() ?? "",
                        "%T" => channel.Parent?.Name ?? "",

                        "%c" => channel.Id.ToString(),
                        "%C" => channel.Name,

                        "%p" => channel.Position?.ToString(CultureInfo.InvariantCulture) ?? "0",
                        "%P"
                            => channel.Parent?.Position?.ToString(CultureInfo.InvariantCulture)
                                ?? "0",

                        "%a"
                            => after?.ToDate().ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)
                                ?? "",
                        "%b"
                            => before?.ToDate().ToString("yyyy-MM-dd", CultureInfo.InvariantCulture)
                                ?? "",
                        "%d"
                            => DateTimeOffset.Now.ToString(
                                "yyyy-MM-dd",
                                CultureInfo.InvariantCulture
                            ),

                        "%%" => "%",
                        _ => m.Value
                    }
                )
        );

    private static string GetOutputBaseFilePath(
        Guild guild,
        Channel channel,
        string outputPath,
        ExportFormat format,
        Snowflake? after = null,
        Snowflake? before = null
    )
    {
        var actualOutputPath = FormatPath(outputPath, guild, channel, after, before);

        // Output is a directory
        if (
            Directory.Exists(actualOutputPath)
            || string.IsNullOrWhiteSpace(Path.GetExtension(actualOutputPath))
        )
        {
            var fileName = GetDefaultOutputFileName(guild, channel, format, after, before);
            return Path.Combine(actualOutputPath, fileName);
        }

        // Output is a file
        return actualOutputPath;
    }
}