# tests/test_diarize.py — SpeakerTracker and speaker_at() diarization logic
#
# All tests are pure Python — no GPU, no pyannote, no HF_TOKEN required.
# The Diarizer class itself is only tested for its from_env() guard and the
# speaker_at() method, both of which run without loading the model.
from __future__ import annotations

import os
import pytest

from cf_voice.diarize import (
    Diarizer,
    SpeakerSegment,
    SpeakerTracker,
    SPEAKER_MULTIPLE,
    SPEAKER_UNKNOWN,
)


# ── SpeakerTracker ────────────────────────────────────────────────────────────

def test_tracker_first_speaker_is_a():
    t = SpeakerTracker()
    assert t.label("SPEAKER_00") == "Speaker A"


def test_tracker_second_speaker_is_b():
    t = SpeakerTracker()
    t.label("SPEAKER_00")
    assert t.label("SPEAKER_01") == "Speaker B"


def test_tracker_same_id_returns_same_label():
    t = SpeakerTracker()
    first = t.label("SPEAKER_00")
    second = t.label("SPEAKER_00")
    assert first == second == "Speaker A"


def test_tracker_26_speakers():
    t = SpeakerTracker()
    labels = [t.label(f"SPEAKER_{i:02d}") for i in range(26)]
    assert labels[0] == "Speaker A"
    assert labels[25] == "Speaker Z"


def test_tracker_27th_speaker_wraps():
    t = SpeakerTracker()
    for i in range(26):
        t.label(f"SPEAKER_{i:02d}")
    label_27 = t.label("SPEAKER_26")
    assert label_27 == "Speaker AA"


def test_tracker_reset_clears_map():
    t = SpeakerTracker()
    t.label("SPEAKER_00")
    t.label("SPEAKER_01")
    t.reset()
    # After reset, SPEAKER_01 is seen as new and maps to "Speaker A" again
    assert t.label("SPEAKER_01") == "Speaker A"


# ── Diarizer.speaker_at() ─────────────────────────────────────────────────────

def _segs(*items: tuple[str, float, float]) -> list[SpeakerSegment]:
    return [SpeakerSegment(speaker_id=s, start_s=st, end_s=en) for s, st, en in items]


def test_speaker_at_single_speaker():
    d = object.__new__(Diarizer)  # bypass __init__ (no GPU needed)
    segs = _segs(("SPEAKER_00", 0.0, 2.0))
    t = SpeakerTracker()
    assert d.speaker_at(segs, 1.0, tracker=t) == "Speaker A"


def test_speaker_at_no_coverage_returns_unknown():
    d = object.__new__(Diarizer)
    segs = _segs(("SPEAKER_00", 0.0, 1.0))
    assert d.speaker_at(segs, 1.5) == SPEAKER_UNKNOWN


def test_speaker_at_empty_segments_returns_unknown():
    d = object.__new__(Diarizer)
    assert d.speaker_at([], 1.0) == SPEAKER_UNKNOWN


def test_speaker_at_overlap_returns_multiple():
    d = object.__new__(Diarizer)
    segs = _segs(
        ("SPEAKER_00", 0.0, 2.0),
        ("SPEAKER_01", 0.5, 2.0),  # overlaps SPEAKER_00 from 0.5s
    )
    assert d.speaker_at(segs, 1.0) == SPEAKER_MULTIPLE


def test_speaker_at_boundary_inclusive():
    d = object.__new__(Diarizer)
    segs = _segs(("SPEAKER_00", 1.0, 2.0))
    t = SpeakerTracker()
    # Exact boundary timestamps are included
    assert d.speaker_at(segs, 1.0, tracker=t) == "Speaker A"
    assert d.speaker_at(segs, 2.0, tracker=t) == "Speaker A"


def test_speaker_at_without_tracker_returns_raw_id():
    d = object.__new__(Diarizer)
    segs = _segs(("SPEAKER_00", 0.0, 2.0))
    assert d.speaker_at(segs, 1.0) == "SPEAKER_00"


def test_speaker_at_two_speakers_no_overlap():
    d = object.__new__(Diarizer)
    t = SpeakerTracker()
    segs = _segs(
        ("SPEAKER_00", 0.0, 1.0),
        ("SPEAKER_01", 1.5, 2.5),
    )
    assert d.speaker_at(segs, 0.5, tracker=t) == "Speaker A"
    assert d.speaker_at(segs, 2.0, tracker=t) == "Speaker B"
    # Gap at 1.2s: window [0.7, 1.7] → SPEAKER_00 has 0.3s, SPEAKER_01 has 0.2s
    # Dominant speaker (SPEAKER_00 = "Speaker A") is returned, not SPEAKER_UNKNOWN.
    assert d.speaker_at(segs, 1.2, tracker=t) == "Speaker A"


# ── Diarizer.from_env() guard ─────────────────────────────────────────────────

def test_from_env_raises_without_hf_token(monkeypatch):
    monkeypatch.delenv("HF_TOKEN", raising=False)
    with pytest.raises(EnvironmentError, match="HF_TOKEN"):
        Diarizer.from_env()