import Testing
import Foundation
import AVFoundation
@testable import Music

// Reproduces the "CoreMediaErrorDomain error -16044 after streaming a few tracks"
// bug (plus the accompanying HALC_ProxyIOContext overload / out-of-order log spew).
//
// Root cause: setting `player = nil` does NOT release an AVPlayer's decode/render
// pipeline — it is the *association* of an AVPlayerItem with an AVPlayer that owns
// the pipeline, and ARC tears it down asynchronously. The teardown path paused and
// nilled the player but never called `replaceCurrentItem(with: nil)`, so each track
// switch leaked a still-associated pipeline. After a handful of tracks they exceed
// CoreMedia's small concurrent-pipeline limit and a new player can't acquire a
// decode session, failing with -16044.
//
// The invariant proven here: tearing down the player must dissociate its item so
// the pipeline is released immediately.
@MainActor
struct PlaybackPipelineTeardownTests {

    // Verifies the streaming provider releases the previous player's pipeline on teardown.
    // Steps:
    // 1. Create a StreamingPlaybackProvider (host/key unused — we drive AVPlayer
    //    directly with a local file URL to bypass the network pre-flight).
    // 2. Start an AVPlayer on a real local audio fixture and capture a strong
    //    reference to it, then confirm the pipeline is established (currentItem set).
    // 3. Tear down via stop() — the same cleanup path a queue advance runs.
    // 4. The captured player must have been dissociated from its item (currentItem
    //    == nil). Before the fix it is still set, so pipelines accumulate.
    @Test func streamingProviderReleasesPipelineOnTeardown() throws {
        // 1. Provider with throwaway connection details.
        let provider = StreamingPlaybackProvider(hostURL: "http://unused.invalid", apiKey: "unused")

        // 2. Start playback on a real local file and grab the AVPlayer it created.
        let fixture = try TestFixtures.shortMP3URL()
        provider.startAVPlayer(url: fixture)
        let firstPlayer = try #require(provider.player)
        #expect(firstPlayer.currentItem != nil)

        // 3. Tear down (queue advance / stop runs this path).
        provider.stop()

        // 4. The pipeline must be released: the item is dissociated from the player.
        #expect(firstPlayer.currentItem == nil)
    }

    // Verifies the local-playback provider (AudioService) has the same fix.
    // Steps:
    // 1. Create an AudioService.
    // 2. Play a real local audio fixture and capture the AVPlayer; confirm the
    //    pipeline is established (currentItem set).
    // 3. Tear down via stop().
    // 4. The captured player must have been dissociated from its item.
    @Test func audioServiceReleasesPipelineOnTeardown() throws {
        // 1. Local playback provider.
        let provider = AudioService()

        // 2. Play a real local file and grab the AVPlayer it created.
        let fixture = try TestFixtures.shortMP3URL()
        provider.play(url: fixture)
        let firstPlayer = try #require(provider.player)
        #expect(firstPlayer.currentItem != nil)

        // 3. Tear down.
        provider.stop()

        // 4. The pipeline must be released: the item is dissociated from the player.
        #expect(firstPlayer.currentItem == nil)
    }
}