using System;
using Paca.Mobile.Core;
using Xunit;

namespace Paca.Tests.Core;

public class BandwidthRateLimiterGateTests
{
    [Fact]
    public void Gate277_BandwidthRateLimiter_UnlimitedPreset_AllowsFullSpeed()
    {
        var limiter = new BandwidthRateLimiter(BandwidthLimitPreset.Unlimited);

        var delay = limiter.ComputeThrottleDelayMs(chunkBytes: 10_000_000, elapsedMs: 10);
        Assert.Equal(0, delay);
    }

    [Fact]
    public void Gate278_BandwidthRateLimiter_TokenBucket_EnforcesByteCap()
    {
        // 1 MB/s = 1,000,000 bytes/sec
        var limiter = new BandwidthRateLimiter(bytesPerSecond: 1_000_000);

        // Downloaded 1MB in 200ms -> should throttle ~800ms
        var delay = limiter.ComputeThrottleDelayMs(chunkBytes: 1_000_000, elapsedMs: 200);
        Assert.InRange(delay, 750, 850);
    }

    [Fact]
    public void Gate279_BandwidthRateLimiter_Presets_FormatLabelsCleanly()
    {
        Assert.Equal("무제한", BandwidthRateLimiter.GetPresetLabel(BandwidthLimitPreset.Unlimited));
        Assert.Equal("10 MB/s (고속)", BandwidthRateLimiter.GetPresetLabel(BandwidthLimitPreset.Fast10MB));
        Assert.Equal("5 MB/s (일반)", BandwidthRateLimiter.GetPresetLabel(BandwidthLimitPreset.Medium5MB));
        Assert.Equal("1 MB/s (절약)", BandwidthRateLimiter.GetPresetLabel(BandwidthLimitPreset.Low1MB));
    }

    [Fact]
    public void Gate280_BandwidthRateLimiter_DynamicRateChange_TakesEffectImmediately()
    {
        var limiter = new BandwidthRateLimiter(bytesPerSecond: 1_000_000);
        Assert.Equal(1_000_000, limiter.BytesPerSecond);

        // Update mid-stream
        limiter.SetRate(5_000_000);
        Assert.Equal(5_000_000, limiter.BytesPerSecond);

        // Now 1MB at 5MB/s expects 200ms total time, elapsed 100ms -> delay ~100ms
        var delay = limiter.ComputeThrottleDelayMs(chunkBytes: 1_000_000, elapsedMs: 100);
        Assert.InRange(delay, 80, 120);
    }
}