"""Pages screenshots"""
from pathlib import Path
from tempfile import NamedTemporaryFile
from typing import Optional

from PIL import Image, ImageChops

from frontools.config import Config
from frontools.sources import Browser
from frontools.utils import (
    get_default_screenshot_directory,
    get_url_slug,
    report_progress,
)


async def screenshot_diff(
    config: Config,
    right_source_name: str,
    output_directory: Optional[str],
    resolution: Optional[str] = None,
) -> None:
    """Compare pages with or without local css"""

    if output_directory is None:
        output_path = get_default_screenshot_directory()
    else:
        output_path = Path(output_directory)

    output_path.mkdir(parents=True)
    left_source = config.default_source
    right_source = config.get_source(right_source_name)

    width: Optional[int] = None
    height: Optional[int] = None
    if resolution is not None:
        [width_str, height_str] = resolution.split("x")
        width = int(width_str)
        height = int(height_str)

    async with left_source.get_browser(width=width, height=height) as left_browser:
        async with right_source.get_browser(
            width=width, height=height
        ) as right_browser:
            urls = [
                (site_name, url)
                for (site_name, site) in config.sites
                for url in site.urls
            ]

            await report_progress(
                "Screenshoting",
                [
                    (
                        url,
                        _diff_url(
                            left_browser,
                            right_browser,
                            url,
                            output_path,
                            site_name,
                        ),
                    )
                    for (site_name, url) in urls
                ],
                nb_workers=3,
            )


async def _diff_url(
    left: Browser,
    right: Browser,
    url: str,
    output_path: Path,
    site_name: str,
) -> None:
    left_bytes = await _screenshot_url(left, url)
    right_bytes = await _screenshot_url(right, url)

    with NamedTemporaryFile(mode="wb") as left_file:
        left_file.write(left_bytes)
        left_image = Image.open(left_file.name).convert("RGB")

    with NamedTemporaryFile(mode="wb") as right_file:
        right_file.write(right_bytes)
        right_image = Image.open(right_file.name).convert("RGB")

    diff = ImageChops.difference(left_image, right_image)

    if not diff.getbbox():
        return

    url_slug = get_url_slug(url)
    if not output_path.is_dir():
        output_path.mkdir()

    with open(output_path / f"{site_name}_{url_slug}_left", "wb") as screenshot_file:
        screenshot_file.write(left_bytes)

    with open(output_path / f"{site_name}_{url_slug}_right", "wb") as screenshot_file:
        screenshot_file.write(right_bytes)


async def _screenshot_url(browser: Browser, url: str) -> bytes:
    async with browser.load_page(url) as page:
        return await page.screenshot(full_page=True)