#!/usr/bin/env python3
"""Check local Collapse height transfers through an owned SDL or TTY 9P session.

python3 -B test/collapse_layout.py zig-out/column-review/bin/pardes-gui
python3 -B test/collapse_layout.py zig-out/column-review/bin/pardes --tty

Measures tagline boundaries in the rendered core grid, not host pixel geometry.
No user session is contacted, and all fixture files live in a temporary directory.
"""
import argparse
from pathlib import Path
import tempfile

from fs import new_pane, session
from ui_review import panes, require, wait_for


def geometry(client, names):
    frame = client.screen()
    rows = [''.join(cell[0] for cell in frame['cells'][row * frame['cols']:(row + 1) * frame['cols']])
            for row in range(frame['rows'])]
    starts = [next((row for row, text in enumerate(rows) if '/' + name + ' ' in text), None)
              for name in names]
    if any(row is None for row in starts) or starts != sorted(set(starts)):
        return None
    ends = starts[1:] + [frame['rows']]
    return tuple((start, end - start) for start, end in zip(starts, ends))


def toggle(client, serial):
    """Execute the default tag's Collapse word without changing any body or tag."""
    pane = f'/self/pane/{serial}'
    tag = client.read(pane + '/tag')
    at = tag.rfind(b' Collapse')
    require(at >= 0, 'default pane tag lacks Collapse')
    at += 1
    client.write(pane + '/event', f'Mx{at} {at + len("Collapse")}\n'.encode())


def run(args):
    binary = str(args.binary.resolve())
    with tempfile.TemporaryDirectory(prefix='pardes-collapse-') as directory:
        root = Path(directory)
        name = 'collapse-layout'
        inherited = {} if args.tty else {
            'PARDES_TEST': '1', 'PARDES_TEST_COLS': '120', 'PARDES_TEST_ROWS': '48',
            'PARDES_TEST_CAPTURE_DIR': str(root),
            'SDL_VIDEODRIVER': 'x11',
        }
        launch = ['-c', 'stty cols 120 rows 48; exec "$@"', name, binary,
                  '--9p=' + name, str(root / (name + '.txt'))]
        with session('/bin/sh', root, name, socket_name=name, tty=True,
                     launch=launch, inherited=inherited) as (client, _):
            serials = [next(iter(panes(client)))]
            names = [f'collapse-{letter}' for letter in 'ABCD']
            contents = b'owned collapse fixture\n' * 60
            for index, label in enumerate(names):
                if index:
                    serials.append(new_pane(client, b''))
                pane = f'/self/pane/{serials[index]}'
                client.write(pane + '/ctl', ('name ' + label + '\n').encode())
                client.write(pane + '/body', contents, truncate=True)
            original = require(wait_for(lambda: geometry(client, names)), 'four pane tags not visible')
            require(all(height > 1 for _, height in original), f'fixture has no body room: {original}')
            for target in [1, 3, 0, 2, 1, 3, 0]:
                recipient = target - 1 if target else 1
                heights = [height for _, height in original]
                heights[recipient] += heights[target] - 1
                heights[target] = 1
                expected = []
                row = original[0][0]
                for height in heights:
                    expected.append((row, height))
                    row += height
                toggle(client, serials[target])
                require(wait_for(lambda: geometry(client, names) == tuple(expected)),
                        f'Collapse {names[target]} changed unrelated geometry: {geometry(client, names)} != {expected}')
                for index in range(4):
                    if index not in [target, recipient]:
                        require(expected[index] == original[index], 'unrelated pane moved')
                toggle(client, serials[target])
                require(wait_for(lambda: geometry(client, names) == original),
                        f'expansion did not restore original geometry: {geometry(client, names)}')
            for serial in serials:
                require(client.read(f'/self/pane/{serial}/body') == contents, 'Collapse changed pane contents')
            require((root / (name + '.txt')).read_bytes() == b'initial\n', 'fixture source file changed')
    print(f'{"TTY" if args.tty else "SDL"}: 7 local collapse/expand pairs, exact unrelated pane geometry, and content preservation passed')


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('binary', type=Path)
    parser.add_argument('--tty', action='store_true')
    run(parser.parse_args())