using System;
using System.Collections.Generic;
using System.Linq;
using Paca.Mobile.Core;
using Xunit;

namespace Paca.Tests.Core;

public class MediaStorageGarbageCollectorGateTests
{
    [Fact]
    public void Gate321_MediaStorageGarbageCollector_ProtectsActiveFiles_AndSelectsStaleOnly()
    {
        var now = new DateTime(2026, 9, 4, 20, 30, 0);

        var candidateFiles = new List<CandidateFileInfo>
        {
            // Stale part file from 3 days ago (150 MB)
            new("C:\\downloads\\movie.mp4.part", 150 * 1024 * 1024, now.AddDays(-3)),
            // Active part file created 10 minutes ago (50 MB) -> MUST BE PROTECTED!
            new("C:\\downloads\\active.mp4.part", 50 * 1024 * 1024, now.AddMinutes(-10)),
            // Normal finished mp4 from 2 days ago -> MUST NOT BE TOUCHED!
            new("C:\\downloads\\finished.mp4", 500 * 1024 * 1024, now.AddDays(-2)),
            // Stale tmp fragment from 40 hours ago (80 MB)
            new("C:\\downloads\\stream_frag.tmp", 80 * 1024 * 1024, now.AddHours(-40))
        };

        var minAge = TimeSpan.FromHours(24);
        var orphans = MediaStorageGarbageCollector.FilterOrphanFiles(candidateFiles, minAge, now);

        Assert.Equal(2, orphans.Count);
        Assert.Contains(orphans, x => x.Path.EndsWith("movie.mp4.part"));
        Assert.Contains(orphans, x => x.Path.EndsWith("stream_frag.tmp"));
        Assert.DoesNotContain(orphans, x => x.Path.EndsWith("active.mp4.part"));
        Assert.DoesNotContain(orphans, x => x.Path.EndsWith("finished.mp4"));
    }

    [Fact]
    public void Gate322_MediaStorageGarbageCollector_CalculatesReclaimableSpace_Correctly()
    {
        var now = new DateTime(2026, 9, 4, 20, 30, 0);
        var candidateFiles = new List<CandidateFileInfo>
        {
            new("C:\\temp\\a.part", 200 * 1024 * 1024, now.AddDays(-2)),
            new("C:\\temp\\b.frag", 300 * 1024 * 1024, now.AddDays(-5))
        };

        var result = MediaStorageGarbageCollector.AnalyzeReclaimableSpace(candidateFiles, TimeSpan.FromHours(24), now);

        Assert.Equal(2, result.OrphanCount);
        Assert.Equal(500 * 1024 * 1024, result.TotalReclaimableBytes);
        Assert.Equal(500.0, result.TotalReclaimableMb);
    }

    [Fact]
    public void Gate323_MediaStorageGarbageCollector_RecognizesAllTemporaryExtensions()
    {
        var tempExts = new[] { ".part", ".tmp", ".frag", ".ytdl", ".download" };

        foreach (var ext in tempExts)
        {
            Assert.True(MediaStorageGarbageCollector.IsTemporaryExtension($"file{ext}"));
        }

        Assert.False(MediaStorageGarbageCollector.IsTemporaryExtension("video.mp4"));
        Assert.False(MediaStorageGarbageCollector.IsTemporaryExtension("audio.mp3"));
        Assert.False(MediaStorageGarbageCollector.IsTemporaryExtension("subtitles.vtt"));
    }

    [Fact]
    public void Gate324_MediaStorageGarbageCollector_PerformsBatchDeletion_Gracefully()
    {
        var filesToDelete = new List<string> { "file1.part", "file2.part", "file3.part" };
        var deletedList = new List<string>();

        var result = MediaStorageGarbageCollector.ExecuteCleanUpWithDeleter(
            filesToDelete,
            deleter: path =>
            {
                if (path == "file2.part") throw new System.IO.IOException("File in use");
                deletedList.Add(path);
            }
        );

        Assert.Equal(2, result.SuccessCount);
        Assert.Equal(1, result.FailedCount);
        Assert.Equal(2, deletedList.Count);
        Assert.Contains("file2.part", result.FailedFiles[0].Path);
    }
}