"""slskd download behaviour: abandoned transfers are cancelled (no pile-up), a stalled peer is
dropped fast, a slow-but-progressing peer is kept, and search candidates are ranked fast/free
peers first."""
import json

import pytest

import lyra_worker.adapters._slskd as slskd_mod
from lyra_worker.adapters._slskd import SlskdClient, _parse_search_responses


class _Resp:
    def __init__(self, payload=None):
        self._p = payload if payload is not None else {}

    def raise_for_status(self):
        pass

    def json(self):
        return self._p


class _SeqRequests:
    """post OK; get() returns successive poll payloads (last one repeats); records DELETEs."""
    def __init__(self, polls):
        self._polls = list(polls)
        self._i = 0
        self.deleted = []

    def post(self, url, **kw):
        return _Resp({})

    def get(self, url, **kw):
        p = self._polls[min(self._i, len(self._polls) - 1)]
        self._i += 1
        return _Resp(p)

    def delete(self, url, **kw):
        self.deleted.append(url)
        return _Resp({})


def _poll(state, bytes_transferred, fid="t1"):
    return {"directories": [{"files": [
        {"filename": "f1.flac", "size": 100, "state": state,
         "bytesTransferred": bytes_transferred, "id": fid},
    ]}]}


def _client(tmp_path):
    return SlskdClient({"slskd.url": "http://x", "slskd.api_key": "k",
                        "slskd.downloadsDir": str(tmp_path)})


_REF = json.dumps({"username": "peerA", "files": [{"filename": "f1.flac", "size": 100}]})


def test_stalled_peer_is_abandoned_and_cancelled(tmp_path, monkeypatch):
    # No byte progress across polls → stall → TimeoutError → the transfer is cancelled.
    monkeypatch.setattr(slskd_mod, "requests", _SeqRequests([_poll("InProgress", 0)]))
    monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
    monkeypatch.setattr(slskd_mod, "_STALL_POLLS", 3)
    fake = slskd_mod.requests

    with pytest.raises(TimeoutError):
        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda _p: None)
    assert any(u.endswith("/api/v0/transfers/downloads/peerA/t1") for u in fake.deleted)


def test_error_state_is_cancelled(tmp_path, monkeypatch):
    monkeypatch.setattr(slskd_mod, "requests", _SeqRequests([_poll("Completed, Errored", 0)]))
    monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
    fake = slskd_mod.requests
    with pytest.raises(RuntimeError):
        _client(tmp_path).download(_REF, str(tmp_path / "dest"), lambda _p: None)
    assert any(u.endswith("/peerA/t1") for u in fake.deleted)


def test_slow_but_progressing_peer_is_not_abandoned(tmp_path, monkeypatch):
    # Bytes climb for more polls than _STALL_POLLS, then complete → success, not a premature stall.
    (tmp_path / "01.flac").write_bytes(b"audio")  # so _retrieve finds the finished file
    ref = json.dumps({"username": "peerA", "files": [{"filename": r"d\Album\01.flac", "size": 5}]})
    polls = [
        {"directories": [{"files": [{"filename": r"d\Album\01.flac", "size": 5,
                                     "state": "InProgress", "bytesTransferred": b, "id": "t1"}]}]}
        for b in (10, 20, 30, 40, 50)
    ] + [
        {"directories": [{"files": [{"filename": r"d\Album\01.flac", "size": 5,
                                     "state": "Completed, Succeeded", "bytesTransferred": 5, "id": "t1"}]}]}
    ]
    monkeypatch.setattr(slskd_mod, "requests", _SeqRequests(polls))
    monkeypatch.setattr(slskd_mod.time, "sleep", lambda _s: None)
    monkeypatch.setattr(slskd_mod, "_STALL_POLLS", 2)  # would fire early if progress were ignored

    out = _client(tmp_path).download(ref, str(tmp_path / "dest"), lambda _p: None)
    assert out["track_count"] == 1
    assert slskd_mod.requests.deleted == []  # completed cleanly → nothing cancelled


def test_parse_ranks_free_and_fast_peers_first():
    responses = [
        {"username": "slow", "hasFreeUploadSlot": True, "uploadSpeed": 100, "queueLength": 0,
         "files": [{"filename": r"a\Artist - Album\01.flac", "size": 5}]},
        {"username": "fast", "hasFreeUploadSlot": True, "uploadSpeed": 9000, "queueLength": 0,
         "files": [{"filename": r"b\Artist - Album\01.flac", "size": 5}]},
        {"username": "queued", "hasFreeUploadSlot": False, "uploadSpeed": 99999, "queueLength": 40,
         "files": [{"filename": r"c\Artist - Album\01.flac", "size": 5}]},
    ]
    peers = [json.loads(c["source_ref"])["username"] for c in _parse_search_responses(responses)]
    assert peers == ["fast", "slow", "queued"]  # free+fast first; no-slot peer last despite speed