import { test } from "node:test";
import assert from "node:assert/strict";

import { createFocusCoordinator, createRevisionGateway } from "../../src/lib/preview/focus.js";
import { createFixtureResolver } from "../../src/lib/preview/resolver.js";

function harness({ audible = true, ackGeneration, ackApplied = true, ackDelayMs = 0, ackHangs = false } = {}) {
    const gateway = createRevisionGateway();
    const resumed = [];
    const status = {
        status: audible ? "playing" : "idle",
        trackKey: "track-A",
        positionMs: 102_000,
        audible,
        playbackGeneration: 7,
    };
    const coord = createFocusCoordinator({
        mainStatus: () => ({ ...status }),
        requestSilence: (gen) =>
            ackHangs
                ? new Promise(() => {})
                : new Promise((res) =>
                      setTimeout(() => res({ generation: ackGeneration ?? gen, applied: ackApplied }), ackDelayMs)
                  ),
        resumeMain: (snapshot, opts) => resumed.push({ snapshot, opts }),
        gateway,
        ackTimeoutMs: 50,
    });
    return { coord, gateway, resumed, status };
}

// ------------------------------------------------------------ acquisition --

test("main idle: focus granted without any silence negotiation, nothing to restore", async () => {
    const { coord, resumed } = harness({ audible: false });
    const { granted, token } = await coord.acquirePreview();
    assert.ok(granted);
    assert.equal(token.pausedByPreview, false);
    const rel = coord.release(token);
    assert.equal(rel.restored, false);
    assert.equal(rel.reason, "main_was_not_audible");
    assert.equal(resumed.length, 0);
});

test("main audible: granted only through a generation-bound acknowledgement", async () => {
    const { coord } = harness({ audible: true });
    const { granted, token } = await coord.acquirePreview();
    assert.ok(granted);
    assert.equal(token.pausedByPreview, true);
    assert.equal(token.snapshot.trackKey, "track-A");
    assert.equal(token.snapshot.positionMs, 102_000);
});

test("stale/wrong-generation ack leaves preview parked", async () => {
    const { coord } = harness({ audible: true, ackGeneration: 3 }); // main is at 7
    const { granted, token } = await coord.acquirePreview();
    assert.equal(granted, false);
    assert.equal(token, null);
});

test("ack that never arrives (timeout) leaves preview parked — renderer status is not proof", async () => {
    const { coord } = harness({ audible: true, ackHangs: true });
    const { granted } = await coord.acquirePreview();
    assert.equal(granted, false);
});

test("ack applied=false is not silence", async () => {
    const { coord } = harness({ audible: true, ackApplied: false });
    const { granted } = await coord.acquirePreview();
    assert.equal(granted, false);
});

test("user command DURING negotiation invalidates the grant", async () => {
    const { coord, gateway } = harness({ audible: true, ackDelayMs: 20 });
    const p = coord.acquirePreview();
    gateway.userSeekOrScratch(); // user scrubbed while we negotiated
    const { granted } = await p;
    assert.equal(granted, false);
});

// -------------------------------------------------------------- release ----

test("clean release restores main at the snapshot, tagged focus-internal", async () => {
    const { coord, gateway, resumed } = harness({ audible: true });
    const { token } = await coord.acquirePreview();
    const rel = coord.release(token);
    assert.ok(rel.restored);
    assert.equal(resumed.length, 1);
    assert.equal(resumed[0].snapshot.trackKey, "track-A");
    assert.equal(resumed[0].snapshot.positionMs, 102_000);
    assert.equal(resumed[0].opts.focusInternal, true);
    // and the focus-internal resume did not invalidate anything
    assert.equal(gateway.changedSince(token.revisions), false);
});

for (const [name, bump] of [
    ["user pause/resume", (g) => g.userPauseResume()],
    ["user starts another track", (g) => g.userPlay()],
    ["queue jump / next / previous", (g) => g.queueJumpOrNextPrev()],
    ["queue mutation", (g) => g.queueMutation()],
    ["seek/scratch", (g) => g.userSeekOrScratch()],
    ["stop", (g) => g.userStop()],
    ["auto-advance", (g) => g.autoAdvance()],
    ["native source change", (g) => g.nativeSourceChange()],
]) {
    test(`no restoration after ${name}`, async () => {
        const { coord, gateway, resumed } = harness({ audible: true });
        const { token } = await coord.acquirePreview();
        bump(gateway);
        const rel = coord.release(token);
        assert.equal(rel.restored, false);
        assert.equal(rel.reason, "revisions_changed");
        assert.equal(resumed.length, 0);
    });
}

test("focus-internal commands do not invalidate their own token", async () => {
    const { coord, gateway } = harness({ audible: true });
    const { token } = await coord.acquirePreview();
    gateway.userPauseResume({ focusInternal: true }); // the coordinator's own pause
    gateway.userPlay({ focusInternal: true });
    assert.equal(gateway.changedSince(token.revisions), false);
    assert.ok(coord.release(token).restored);
});

test("play-full handoff never restores the old track", async () => {
    const { coord, resumed } = harness({ audible: true });
    await coord.acquirePreview();
    const h = coord.handoffToMain();
    assert.equal(h.restored, false);
    assert.equal(h.reason, "handoff");
    assert.equal(resumed.length, 0);
    assert.equal(coord.owner(), "main");
});

test("a stale token cannot release anything", async () => {
    const { coord } = harness({ audible: true });
    const { token } = await coord.acquirePreview();
    coord.release(token);
    const again = coord.release(token);
    assert.equal(again.restored, false);
    assert.equal(again.reason, "stale_token");
});

// ------------------------------------------------------------- resolver ----

test("fixture resolver: scripted fail-once-then-succeed with bypassCache", async () => {
    const src = { provider: "deezer", providerTrackId: "42", matchConfidence: "native" };
    const resolver = createFixtureResolver({
        42: (n) => (n === 1 ? { failure: "stale_lease", retryable: true } : { opaqueLeaseId: "op-fresh" }),
    });
    const first = await resolver.resolve(src, { generation: 5 });
    assert.equal(first.ok, false);
    assert.equal(first.failure, "stale_lease");
    assert.ok(first.retryable);
    const second = await resolver.resolve(src, { generation: 5, bypassCache: true });
    assert.ok(second.ok);
    assert.equal(second.lease.transport, "native");
    assert.equal(second.lease.opaqueLeaseId, "op-fresh");
    assert.equal(resolver.callCount("42"), 2);
});

test("fixture resolver: unknown id classifies as not_found, not an exception", async () => {
    const resolver = createFixtureResolver({});
    const r = await resolver.resolve({ provider: "deezer", providerTrackId: "999", matchConfidence: "native" }, { generation: 1 });
    assert.equal(r.ok, false);
    assert.equal(r.failure, "not_found");
    assert.equal(r.retryable, false);
});