#!/usr/bin/env python3
"""Exercise camera defaults/errors and single-frame/movie agreement (CPU PNG builds)."""
import os
from pathlib import Path
import struct
import subprocess
import sys
import tempfile
import zlib

BUILD = Path(sys.argv[1] if len(sys.argv) > 1 else 'build/Release').resolve()
ENV = dict(os.environ, OMP_NUM_THREADS='4')


def run(binary, *args, ok=True):
    result = subprocess.run([str(binary), *map(str, args)], env=ENV,
                            capture_output=True, text=True)
    if (result.returncode == 0) != ok:
        raise AssertionError(f'{binary.name} {args}: {result.returncode}\n{result.stderr}')
    return result


def image_payload(path):
    data = path.read_bytes()
    assert data[:8] == b'\x89PNG\r\n\x1a\n'
    offset, compressed = 8, bytearray()
    while offset < len(data):
        count, kind = struct.unpack_from('>I4s', data, offset)
        payload = data[offset + 8:offset + 8 + count]
        if kind == b'IHDR':
            assert struct.unpack_from('>II', payload) == (64, 48)
        if kind == b'IDAT':
            compressed.extend(payload)
        offset += count + 12
    raw = zlib.decompress(compressed)
    assert any(raw), f'empty image: {path}'
    return raw


def map_vertices(path):
    data = path.read_bytes()
    assert data[:8] == b'GRLENS\x01\x00'
    assert struct.unpack_from('<Q', data, 32)[0] == 1
    vertices, triangles = struct.unpack_from('<QQ', data, 64)
    offset = 80
    values = []
    for _ in range(vertices):
        values.append(struct.unpack_from('<9dI', data, offset))
        offset += 76
    return values, data[offset:offset + triangles * 28]


with tempfile.TemporaryDirectory(prefix='gr-camera-cli-') as directory:
    tmp = Path(directory)
    for backend in ('minkowski', 'schwarzschild'):
        binary = BUILD / f'{backend}_sky'
        help_text = run(binary, '--help').stdout
        for option in ('--observer-position', '--observer-velocity', '--camera-roll-deg'):
            assert option in help_text
        assert '--observer-inward-speed' not in help_text
        common = ['--catalog', 'assets/sky_grid_5deg.csv', '--width', 64,
                  '--height', 48, '--fov-deg', 80, '--exposure', 0.1,
                  '--coarse-cell-pixels', 8, '--refine-max-level', 0, '--psf-relative-tail', 1e-4]
        def render(name, *options):
            path = tmp / f'{backend}_{name}.png'
            run(binary, *common, '--output', path, *options)
            return image_payload(path)

        # Equivalent independently specified and inferred camera geometry.
        inferred = render('position', '--observer-position', -30, 0, 0)
        explicit = render('explicit', '--observer-position', -30, 0, 0,
                          '--look-ra-deg', 0, '--look-dec-deg', 0)
        angled = render('angle', '--look-ra-deg', 0, '--look-dec-deg', 0)
        assert inferred == explicit == angled
        pole = render('pole', '--observer-position', 0, 0, 30)
        assert pole == render('pole_explicit', '--observer-position', 0, 0, 30,
                              '--look-ra-deg', 0, '--look-dec-deg', -90)
        default = render('default')
        pos = (0, 0, 0) if backend == 'minkowski' else (0, 0, 30)
        assert default == render('default_explicit', '--observer-position', *pos,
                                 '--look-ra-deg', 90, '--look-dec-deg', -90)
        assert render('radius', '--observer-radius', 40) == render(
            'radius_explicit', '--observer-radius', 40, '--look-ra-deg', 90,
            '--look-dec-deg', -90)
        for partial, value, ra, dec in [('--look-ra-deg', 37, 37, -90),
                                       ('--look-dec-deg', -23, 90, -23)]:
            assert render('partial', partial, value) == render(
                'complete', '--look-ra-deg', ra, '--look-dec-deg', dec)
        errors = [
            (['--observer-position', 1, 2], None),
            (['--observer-position', 1, 2, 'nan'], None),
            (['--observer-velocity', 0, 0, 'inf'], None),
            (['--look-ra-deg', 'nan'], None),
            (['--look-dec-deg', 'inf'], None),
            (['--observer-radius', 'nan'], None),
            (['--observer-radius', 0], None),
            (['--camera-roll-deg', 'nan'], None),
            (['--observer-position', 0, 0, 0], 'Cannot infer'),
            (['--observer-position', 3, 4, 5, '--observer-radius', 30], 'mutually exclusive'),
            (['--observer-velocity', 10, 0, 0], 'not timelike'),
            (['--observer-inward-speed', 0], None),
            (['--observer-track', 'missing.csv', '--observer-velocity', 0, 0, 0], 'cannot be combined'),
            (['--frames-dir', tmp, '--look-ra-deg', 0], 'cannot be combined'),
            (['--lens-map-input', 'missing.grlens', '--camera-roll-deg', 0], 'cannot be combined'),
        ]
        if backend == 'schwarzschild':
            errors += [(['--observer-position', 1.5, 0, 0, '--observer-velocity', -0.5, 0, 0], 'capture cutoff'),
                       (['--observer-position', 1.75, 0, 0], 'not timelike')]
            render('inside', '--observer-position', 1.75, 0, 0,
                   '--observer-velocity', -0.5, 0, 0, '--look-ra-deg', 0, '--look-dec-deg', 0)
        for options, message in errors:
            missing_catalog = tmp / 'should_not_be_created.csv'
            result = run(binary, '--catalog', missing_catalog, *options, ok=False)
            if message:
                assert message in result.stderr, result.stderr
            assert not missing_catalog.exists(), result.stderr
            assert 'PSF cache ready' not in result.stderr
        track = tmp / f'{backend}.csv'
        run(BUILD / f'test_observer_{backend}', track)
        single_map, movie_map = tmp / 'single.grlens', tmp / 'movie.grlens'
        single = render('moving', '--observer-position', 3, -4, 5,
                        '--observer-velocity', 0.2, -0.1, 0.3,
                        '--look-ra-deg', 37, '--look-dec-deg', -23,
                        '--camera-roll-deg', 19, '--lens-map-output', single_map)
        run(binary, *common, '--observer-track', track, '--frames-dir', tmp,
            '--frames-prefix', backend, '--duration', 0, '--fps', 1,
            '--lens-map-output', movie_map)
        movie = image_payload(tmp / f'{backend}_000000.png')
        assert single == movie, f'{backend}: single/movie PNG mismatch'
        a, ta = map_vertices(single_map)
        b, tb = map_vertices(movie_map)
        assert len(a) == len(b) and ta == tb
        max_error = 0
        for x, y in zip(a, b):
            assert x[-1] == y[-1], 'ray classification mismatch'
            max_error = max(max_error, *(abs(v - w) for v, w in zip(x[:-1], y[:-1])))
        assert max_error < 1e-9, max_error
        # A map import must still work without evaluating a camera/metric.
        assert single == render('import', '--lens-map-input', single_map)
        print(f'{backend}: CLI checks passed; single/movie PNG identical, map max error {max_error:.3g}', flush=True)