"""The BW filename encodes the serial NUMBER, never the family prefix.

"BE" is a MiniMate Plus; "BA" is a BlastMate.  Both are Series III and their
files are byte-compatible — the whole archive's 1,493 BlastMate binaries
decode through the same codec at 100% — so the only thing that distinguishes
them downstream is the serial string, and that lives in the file body.

Synthesising the prefix as "BE" files a BlastMate under a unit that does not
exist.  Four units in the DL2 archive are affected: BA9229, BA10060, BA10895
and BA15957.
"""
from __future__ import annotations

import pytest

from minimateplus.client import _decode_0a_partial_header
from sfm.waveform_store import (
    _serial_from_bw_bytes,
    _serial_from_bw_filename,
    _serial_number_from_bw_filename,
)


# ── the filename gives a number, and only a number ──────────────────────────

@pytest.mark.parametrize("name,num", [
    ("P036L318.C80H", 14036),   # BE14036
    ("H907KWRK.WB0H", 6907),    # BE6907
    ("M529LKIQ.G10",  11529),   # BE11529
    ("T003LQ9K.OE0H", 18003),   # BE18003
    ("L895K63F.GE0W", 10895),   # BA10895 — a BlastMate
    ("K229HGQI.XO0W", 9229),    # BA9229  — a BlastMate
])
def test_number_from_filename(name, num):
    assert _serial_number_from_bw_filename(name) == num


@pytest.mark.parametrize("name", ["", "not_a_bw_file.bin", "AB12", "1234ABCD.XX0W"])
def test_number_from_filename_rejects_junk(name):
    assert _serial_number_from_bw_filename(name) is None


def test_filename_only_decoder_is_a_guess():
    """It still answers "BE" — that is why it must not be the first choice."""
    assert _serial_from_bw_filename("L895K63F.GE0W") == "BE10895"
    assert _serial_from_bw_filename("M529LKIQ.G10") == "BE11529"
    assert _serial_from_bw_filename("nonsense") is None


# ── the body carries the truth ──────────────────────────────────────────────

def _body(serial: bytes) -> bytes:
    return b"\x00" * 32 + b"STRT" + b"\xff\xfe" + serial + b"\x00Geo: 0.254 in/s\x00"


def test_body_wins_for_a_blastmate():
    assert _serial_from_bw_bytes(_body(b"BA10895"), "L895K63F.GE0W") == "BA10895"


def test_body_wins_for_a_minimate():
    assert _serial_from_bw_bytes(_body(b"BE11529"), "M529LKIQ.G10") == "BE11529"


def test_body_candidate_must_match_the_filename_number():
    """A serial-shaped byte run that disagrees with the filename is ignored."""
    assert _serial_from_bw_bytes(_body(b"XX99999"), "L895K63F.GE0W") is None


def test_body_tolerates_a_leading_zero():
    assert _serial_from_bw_bytes(_body(b"BA09229"), "K229HGQI.XO0W") == "BA09229"


@pytest.mark.parametrize("data,name", [
    (b"", "L895K63F.GE0W"),          # no bytes
    (_body(b"BA10895"), "junk.bin"),  # no derivable number
])
def test_body_returns_none_when_it_cannot_decide(data, name):
    assert _serial_from_bw_bytes(data, name) is None


# ── the live monitor-log path ───────────────────────────────────────────────

def _partial_record(serial: bytes) -> bytes:
    """0x2C partial record: type, prefix, two 9-byte timestamps, then ASCII."""
    ts = bytes([11, 0x10, 4, 0x07, 0xE9, 0, 16, 2, 0])   # 2025-04-11 16:02:00
    return (bytes([0x2C]) + b"\x00" * 10 + ts + ts
            + b"\x00\x00\x00\x00" + serial + b"\x00Geo: 0.254 in/s\x00")


@pytest.mark.parametrize("serial", [b"BE11529", b"BA10895", b"UM11719"])
def test_monitor_log_reads_any_family_prefix(serial):
    entry = _decode_0a_partial_header(_partial_record(serial), 0, b"\x01\x11\x00\x00")
    assert entry is not None
    assert entry.serial == serial.decode()


def test_monitor_log_geo_threshold_survives_a_blastmate():
    """The old find(b"BE") skipped the whole block, losing geo too."""
    entry = _decode_0a_partial_header(_partial_record(b"BA10895"), 0, b"\x01\x11\x00\x00")
    assert entry is not None
    assert entry.geo_threshold_ips == pytest.approx(0.254)