"""Tests for serialcomm/data_parser.py binary parsing pipeline."""

import pytest

from pygui.serialcomm.data_parser import (
    _convert_debug_temp,
    _convert_hex_to_temp,
    convert_to_debug_temperatures,
    convert_to_temperatures,
    csv_column_count,
    parse_binary_data,
    remove_trailing_zeros,
    save_debug_csv,
    save_to_csv,
)

# ── csv_column_count ──────────────────────────────────────────────────────────


class TestCsvColumnCount:
    def test_a_family(self):
        assert csv_column_count("A") == 48

    def test_e_family(self):
        assert csv_column_count("E") == 48

    def test_p_family(self):
        assert csv_column_count("P") == 48

    def test_b_family(self):
        assert csv_column_count("B") == 29

    def test_c_family(self):
        assert csv_column_count("C") == 29

    def test_d_family(self):
        assert csv_column_count("D") == 29

    def test_f_family(self):
        assert csv_column_count("F") == 22

    def test_x_family(self):
        assert csv_column_count("X") == 80

    def test_unknown_family_returns_zero(self):
        assert csv_column_count("Z") == 0

    def test_empty_string_returns_zero(self):
        assert csv_column_count("") == 0


# ── Temperature conversion ────────────────────────────────────────────────────


class TestConvertHexToTemp:
    """Spot-check known hex → temperature values.

    Reference values derived from the C# ConvertBinaryArrayToDecimal logic.
    """

    def test_zero_hex_gives_zero_standard(self):
        # 0x0000 → all bits 0 → temperature 0.0
        result = _convert_hex_to_temp("0000", "B")
        assert result == 0.0

    def test_zero_hex_gives_zero_aep(self):
        result = _convert_hex_to_temp("0000", "A")
        assert result == 0.0

    def test_standard_positive_small(self):
        # 0x0050 = 0000 0000 0101 0000 → bits 1-11 = 000000000101 = 4+1 = 5, fraction bits = 00 → 5.0°C
        result = _convert_hex_to_temp("0050", "B")
        assert result == pytest.approx(5.0, abs=0.1)

    def test_standard_negative(self):
        # Sign bit set → negative temperature
        result = _convert_hex_to_temp("8050", "B")
        assert result < 0

    def test_aep_positive(self):
        # 0x6400 = 0110 0100 0000 0000
        # sign=0, int bits 1-8 = 11001000 = ...
        # Just check it's in a reasonable range
        result = _convert_hex_to_temp("6400", "A")
        assert -300 < result < 300

    def test_x_family_uses_aep(self):
        # X uses same AEP formula as A
        result_x = _convert_hex_to_temp("0100", "X")
        result_a = _convert_hex_to_temp("0100", "A")
        assert result_x == result_a

    def test_unknown_family_falls_back_to_standard(self):
        # Should not raise; falls back to standard formula
        result = _convert_hex_to_temp("0050", "Z")
        assert isinstance(result, float)


# ── Binary parsing ────────────────────────────────────────────────────────────


def _make_p_block(num_blocks: int = 1, value: int = 0x0100) -> bytes:
    """Build synthetic P-family binary data.

    Each block is 256 words (512 bytes). Words 0-243 hold `value`,
    words 244-255 are zero (overhead).
    """
    data = bytearray()
    for _ in range(num_blocks):
        for i in range(256):
            word = value if i < 244 else 0
            data += word.to_bytes(2, byteorder="little")
    return bytes(data)


def _make_x_block(num_blocks: int = 1, value: int = 0x0100) -> bytes:
    """Build synthetic X-family binary data.

    Each block is 256 words (512 bytes). Words 0-79 hold `value`,
    words 80-255 are zero (overhead).
    """
    data = bytearray()
    for _ in range(num_blocks):
        for i in range(256):
            word = value if i < 80 else 0
            data += word.to_bytes(2, byteorder="little")
    return bytes(data)


class TestParseBinaryData:
    def test_p_family_single_block_returns_one_row(self):
        data = _make_p_block(1)
        result = parse_binary_data(data, "P")
        assert result is not None
        assert len(result) == 1

    def test_p_family_single_block_row_has_244_sensors(self):
        data = _make_p_block(1)
        result = parse_binary_data(data, "P")
        assert result is not None
        assert len(result[0]) == 244

    def test_p_family_two_blocks_returns_two_rows(self):
        data = _make_p_block(2)
        result = parse_binary_data(data, "P")
        assert result is not None
        assert len(result) == 2

    def test_p_family_hex_values_are_4_chars(self):
        data = _make_p_block(1)
        result = parse_binary_data(data, "P")
        assert result is not None
        for hex_val in result[0]:
            assert len(hex_val) == 4

    def test_x_family_single_block_returns_one_row(self):
        data = _make_x_block(1)
        result = parse_binary_data(data, "X")
        assert result is not None
        assert len(result) == 1

    def test_x_family_single_block_row_has_80_sensors(self):
        data = _make_x_block(1)
        result = parse_binary_data(data, "X")
        assert result is not None
        assert len(result[0]) == 80

    def test_a_family_uses_p_parser(self):
        # A/B/C/D/E/F all route to _parse_p_binary
        data = _make_p_block(1)
        result = parse_binary_data(data, "A")
        assert result is not None
        assert len(result[0]) == 244

    def test_empty_bytes_returns_empty_list(self):
        result = parse_binary_data(b"", "P")
        # No full block → no rows
        assert result is not None
        assert result == []


# ── convert_to_temperatures ───────────────────────────────────────────────────


class TestConvertToTemperatures:
    def test_returns_same_shape(self):
        hex_data = [["0000", "0000"], ["0000", "0000"]]
        result = convert_to_temperatures(hex_data, "B")
        assert len(result) == 2
        assert len(result[0]) == 2

    def test_zero_hex_gives_zero_string(self):
        hex_data = [["0000"]]
        result = convert_to_temperatures(hex_data, "B")
        assert result[0][0] == "0.0"

    def test_values_are_strings(self):
        hex_data = [["0050"]]
        result = convert_to_temperatures(hex_data, "B")
        assert isinstance(result[0][0], str)
        # Must be parseable as float
        float(result[0][0])

    def test_p_family_single_block(self):
        data = _make_p_block(1, value=0x0100)
        hex_data = parse_binary_data(data, "P")
        assert hex_data is not None
        result = convert_to_temperatures(hex_data, "P")
        assert len(result) == 1
        assert all(isinstance(v, str) for v in result[0])


# ── remove_trailing_zeros ─────────────────────────────────────────────────────


class TestRemoveTrailingZeros:
    def test_removes_all_zero_last_row(self):
        data = [["25.0", "24.5"], ["0.0", "0.0"]]
        remove_trailing_zeros(data)
        assert len(data) == 1

    def test_preserves_non_zero_rows(self):
        data = [["25.0", "24.5"], ["23.0", "22.0"]]
        remove_trailing_zeros(data)
        assert len(data) == 2

    def test_removes_multiple_trailing_zero_rows(self):
        data = [["25.0"], ["0.0"], ["0.0"]]
        remove_trailing_zeros(data)
        assert len(data) == 1

    def test_all_zero_data_becomes_empty(self):
        data = [["0.0", "0.0"], ["0.0", "0.0"]]
        remove_trailing_zeros(data)
        assert data == []

    def test_empty_list_stays_empty(self):
        data = []
        remove_trailing_zeros(data)
        assert data == []

    def test_mixed_keeps_first_nonzero(self):
        data = [["25.0"], ["1.0"], ["0.0"]]
        remove_trailing_zeros(data)
        assert len(data) == 2

    def test_preserves_negative_temperatures(self):
        data = [["25.0", "24.5"], ["-5.5", "-10.0"]]
        remove_trailing_zeros(data)
        assert len(data) == 2


# ── save_to_csv ───────────────────────────────────────────────────────────────


class TestSaveToCsv:
    def test_creates_file(self, tmp_path):
        data = [["25.0", "24.5"], ["23.0", "22.0"]]
        result = save_to_csv(data, "P", "P00001", str(tmp_path))
        assert result is not None
        from pathlib import Path

        assert Path(result).exists()

    def test_filename_contains_serial(self, tmp_path):
        data = [["25.0"]]
        result = save_to_csv(data, "P", "P12345", str(tmp_path))
        assert result is not None
        assert "P12345" in result

    def test_csv_header_wins_when_data_wider_than_display(self, tmp_path):
        # Header count = max(csv_column_count, data width).
        # When data has 60 columns and P display is 48, header is 60 — no truncation.
        data = [[f"{i}.0" for i in range(60)]]
        result = save_to_csv(data, "P", "P00001", str(tmp_path))
        assert result is not None
        headers = open(result).readline().strip().split(",")
        assert len(headers) == 60, "data width 60 should win over display 48"
        assert headers[0] == "Sensor1"
        assert headers[-1] == "Sensor60"

    def test_csv_uses_display_count_when_data_is_narrower(self, tmp_path):
        # When data has fewer columns than the display count, pad to display.
        data = [["25.0"]]
        result = save_to_csv(data, "X", "X00001", str(tmp_path))
        assert result is not None
        headers = open(result).readline().strip().split(",")
        # X display = 80, data = 1 → headers = 80
        assert len(headers) == 80

    def test_csv_row_count_matches_data(self, tmp_path):
        data = [["25.0"], ["24.5"], ["23.0"]]
        result = save_to_csv(data, "P", "P00001", str(tmp_path))
        assert result is not None
        lines = open(result).readlines()
        # 1 header + 3 data rows
        assert len(lines) == 4

    def test_creates_output_dir_if_missing(self, tmp_path):
        nested = str(tmp_path / "a" / "b" / "c")
        data = [["25.0"]]
        result = save_to_csv(data, "P", "P00001", nested)
        assert result is not None
        from pathlib import Path

        assert Path(result).exists()

    def test_returns_none_on_invalid_path(self):
        data = [["25.0"]]
        result = save_to_csv(data, "P", "P00001", "/\x00invalid\x00path")
        assert result is None

    def test_preserves_all_columns_when_data_wider_than_display(self, tmp_path):
        # Bug fix: when data has more columns than csv_column_count(family),
        # all data columns must be preserved (no silent truncation).
        data = [[f"{i}.0" for i in range(244)]]
        result = save_to_csv(data, "P", "P00001", str(tmp_path))
        assert result is not None
        with open(result) as f:
            lines = f.readlines()
        headers = lines[0].strip().split(",")
        data_row = lines[1].strip().split(",")
        # All 244 columns should be preserved, not truncated to 48
        assert len(headers) == 244, f"expected 244 cols, got {len(headers)}"
        assert len(data_row) == 244, f"expected 244 data cols, got {len(data_row)}"
        assert data_row[243] == "243.0", "last column value must be preserved"


# ── Debug temperature conversion ───────────────────────────────────────────────


class TestConvertDebugTemp:
    """Spot-check known hex → debug temperature values.

    Reference values derived from C#'s ConvertBinaryArrayToDebugTemp
    (bits 4-14 scaled by 2**(i-8), sign at bit 0 — no family branching).
    """

    def test_zero_hex_gives_zero(self):
        assert _convert_debug_temp("0000") == 0.0

    def test_bit8_gives_one(self):
        # bit index 8 set (value 0x0080) → contributes 2**(8-8) = 1.0
        assert _convert_debug_temp("0080") == pytest.approx(1.0, abs=0.01)

    def test_sign_bit_negates(self):
        # sign bit (bit 0) + bit 8 → -1.0
        assert _convert_debug_temp("8080") == pytest.approx(-1.0, abs=0.01)

    def test_no_family_branching(self):
        # Debug conversion takes no family code — same result regardless
        assert _convert_debug_temp("0080") == _convert_debug_temp("0080")


class TestConvertToDebugTemperatures:
    def test_returns_same_shape(self):
        hex_data = [["0080", "0000"], ["8080", "0000"]]
        result = convert_to_debug_temperatures(hex_data)
        assert len(result) == 2
        assert len(result[0]) == 2

    def test_values_are_strings(self):
        result = convert_to_debug_temperatures([["0080"]])
        assert isinstance(result[0][0], str)

    def test_converts_known_value(self):
        result = convert_to_debug_temperatures([["0080"]])
        assert float(result[0][0]) == pytest.approx(1.0, abs=0.01)


# ── Debug CSV export ────────────────────────────────────────────────────────────


class TestSaveDebugCsv:
    def test_creates_file_with_fixed_name(self, tmp_path):
        result = save_debug_csv([["25.0"]], [["1.0"]], str(tmp_path))
        assert result is not None
        assert result.endswith("debug_info.csv")

    def test_header_alternates_sensor_and_debug(self, tmp_path):
        result = save_debug_csv([["25.0", "24.5"]], [["1.0", "2.0"]], str(tmp_path))
        assert result is not None
        header = open(result).readline().strip()
        assert header == "Sensor1,Debug1,Sensor2,Debug2"

    def test_data_row_alternates_values(self, tmp_path):
        result = save_debug_csv([["25.0", "24.5"]], [["1.0", "2.0"]], str(tmp_path))
        assert result is not None
        lines = open(result).readlines()
        assert lines[1].strip() == "25.0,1.0,24.5,2.0"

    def test_truncates_to_shorter_row_count(self, tmp_path):
        temp_data = [["25.0"], ["24.0"], ["23.0"]]
        debug_data = [["1.0"], ["2.0"]]
        result = save_debug_csv(temp_data, debug_data, str(tmp_path))
        assert result is not None
        lines = open(result).readlines()
        assert len(lines) == 3  # 1 header + 2 data rows (shorter of the two)

    def test_truncates_to_shorter_column_count(self, tmp_path):
        temp_data = [["25.0", "24.0", "23.0"]]
        debug_data = [["1.0", "2.0"]]
        result = save_debug_csv(temp_data, debug_data, str(tmp_path))
        assert result is not None
        header = open(result).readline().strip()
        assert header == "Sensor1,Debug1,Sensor2,Debug2"

    def test_returns_none_on_empty_temp_data(self, tmp_path):
        assert save_debug_csv([], [["1.0"]], str(tmp_path)) is None

    def test_returns_none_on_empty_debug_data(self, tmp_path):
        assert save_debug_csv([["25.0"]], [], str(tmp_path)) is None

    def test_creates_output_dir_if_missing(self, tmp_path):
        nested = str(tmp_path / "a" / "b")
        result = save_debug_csv([["25.0"]], [["1.0"]], nested)
        assert result is not None
        from pathlib import Path

        assert Path(result).exists()