"""Tests for spruce.exif — mosaic EXIF injection."""

import shutil
from pathlib import Path

import piexif
import pytest
from piexif import ExifIFD, GPSIFD, ImageIFD

from spruce.exif import USER_COMMENT_ASCII, write_mosaic_exif

FIXTURES = Path(__file__).parent / "fixtures"
BLANK_JPEG = FIXTURES / "blank.jpg"


def _dms_pair_to_float(num: int, den: int) -> float:
    return num / den if den else 0.0


def _dms_to_deg(
    ref: bytes, dms: list[tuple[tuple[int, int], tuple[int, int], tuple[int, int]]]
) -> float:
    d0, m0, s0 = dms
    deg = (
        _dms_pair_to_float(d0[0], d0[1])
        + _dms_pair_to_float(m0[0], m0[1]) / 60.0
        + _dms_pair_to_float(s0[0], s0[1]) / 3600.0
    )
    if ref in (b"S", b"W"):
        return -deg
    return deg


@pytest.fixture
def tmp_jpeg(tmp_path: Path) -> Path:
    dest = tmp_path / "mosaic.jpg"
    shutil.copy(BLANK_JPEG, dest)
    return dest


@pytest.fixture
def scan_meta() -> dict:
    return {
        "scan_id": 157743,
        "name": "Plot 7 AMR18 Full tube scan",
        "scan_time": "2024-06-28 11:00:00",
        "user": "Joanne",
        "nx": 103,
        "ny": 328,
        "dx": 3.01,
        "dy": 2.26,
        "end_x": 310.0,
        "end_y": 740.0,
    }


@pytest.fixture
def machine() -> dict:
    return {"label": "BW1-7 [AMR-18]", "version": "3.0.0.18", "machine_id": "7"}


def test_write_mosaic_exif_round_trip(tmp_jpeg: Path, scan_meta: dict, machine: dict):
    assert write_mosaic_exif(
        tmp_jpeg,
        scan_meta,
        machine,
        157743,
        None,
    )
    exif = piexif.load(str(tmp_jpeg))
    assert exif["Exif"][ExifIFD.DateTimeOriginal] == b"2024:06:28 11:00:00"
    assert (
        exif["0th"][ImageIFD.ImageDescription]
        == b"BW1-7 [AMR-18] scan 157743 (Plot 7 AMR18 Full tube scan)"
    )
    assert exif["0th"][ImageIFD.Artist] == b"Joanne"
    assert exif["0th"][ImageIFD.Software] == b"RootView 3.0.0.18"
    assert exif["0th"][ImageIFD.ProcessingSoftware] == b"spruce-scraper/1.0"
    uc = exif["Exif"][ExifIFD.UserComment]
    assert uc.startswith(USER_COMMENT_ASCII)
    tail = uc[len(USER_COMMENT_ASCII) :]
    assert b"SPRUCE scan 157743" in tail
    assert b"103x328" in tail
    assert b"see metadata.json" in tail
    assert b"plot_number" not in tail
    assert ImageIFD.XPKeywords not in exif["0th"]
    assert "GPS" not in exif or not exif["GPS"]


def test_gps_decode(tmp_jpeg: Path, scan_meta: dict, machine: dict):
    mmeta = {
        "latitude_wgs_84": 47.5047,
        "longitude_wgs_84": -93.4530,
        "elevation_masl": 418.0,
    }
    assert write_mosaic_exif(tmp_jpeg, scan_meta, machine, 157743, mmeta)
    exif = piexif.load(str(tmp_jpeg))
    gps = exif["GPS"]
    lat = _dms_to_deg(gps[GPSIFD.GPSLatitudeRef], gps[GPSIFD.GPSLatitude])
    lon = _dms_to_deg(gps[GPSIFD.GPSLongitudeRef], gps[GPSIFD.GPSLongitude])
    assert abs(lat - 47.5047) < 1e-5
    assert abs(lon - (-93.4530)) < 1e-5
    alt = gps[GPSIFD.GPSAltitude]
    assert alt[0] / alt[1] == pytest.approx(418.0)


def test_no_gps_no_keywords_when_meta_none(
    tmp_jpeg: Path, scan_meta: dict, machine: dict
):
    assert write_mosaic_exif(tmp_jpeg, scan_meta, machine, 157743, None)
    exif = piexif.load(str(tmp_jpeg))
    assert ImageIFD.XPKeywords not in exif["0th"]
    assert "GPS" not in exif or not exif["GPS"]


def test_xp_keywords_treatment(tmp_jpeg: Path, scan_meta: dict, machine: dict):
    mmeta = {
        "plot_number": 7,
        "enclosure": False,
        "temp_treatment": 2.25,
        "co2_treatment": "ambient",
    }
    assert write_mosaic_exif(tmp_jpeg, scan_meta, machine, 157743, mmeta)
    exif = piexif.load(str(tmp_jpeg))
    raw = exif["0th"][ImageIFD.XPKeywords]
    text = bytes(raw).decode("utf-16le").rstrip("\x00")
    assert "SPRUCE" in text
    assert "plot 7" in text
    assert "no enclosure" in text
    assert "temp" in text
    assert "2.25" in text
    assert "aCO2" in text
    uc = exif["Exif"][ExifIFD.UserComment]
    uct = uc[len(USER_COMMENT_ASCII) :].decode("ascii", errors="replace")
    assert "plot_number 7" in uct
    assert "enclosure no" in uct
    assert "temp_treatment 2.25" in uct
    assert "co2_treatment ambient" in uct