1#!/usr/bin/env python3
2"""
3Copy a new set of CSS files from a local checkout of my website, and
4create a `palette.json` in the root of the repo.
5"""
6
7import glob
8import json
9from pathlib import Path
10import re
11import shutil
12import subprocess
13
14from palette import BaseColours, BasePalette
15
16
17def get_alexwlchan_net_css(css_name: str) -> tuple[str, str]:
18    """
19    Get a copy of a CSS file from a local checkout of my website.
20
21    This returns a tuple: the commit ID and CSS text.
22    """
23    repo_path = Path.home() / "repos/alexwlchan.net"
24    css_path = repo_path / "src/_scss" / css_name
25
26    # Get the commit ID of the last change to this file
27    output = subprocess.check_output(
28        ["git", "rev-list", "-1", "HEAD", "--", str(css_path)],
29        text=True,
30        cwd=repo_path,
31    )
32    commit_id = output[:7]
33
34    vendor_path = Path("css") / f"{css_path.stem}.{commit_id}{css_path.suffix}"
35    vendor_path.parent.mkdir(exist_ok=True)
36
37    # If we don't have a vendored copy of the file in this repo, delete
38    # any previously-vendored copies then copy in the new version.
39    if not vendor_path.exists():
40        for f in glob.glob(f"css/{css_path.stem}.*"):
41            Path(f).unlink()
42
43        shutil.copyfile(css_path, vendor_path)
44
45    return commit_id, vendor_path.read_text()
46
47
48def get_colour_variable(css: str, *, name: str) -> str:
49    """
50    Extract a CSS variable from a snippet of CSS.
51    """
52    # Example matches:
53    #
54    #     --red: #ff0000;
55    #     --red:   #ff0000;
56    #     --red: #ff0000ff;
57    #
58    m = re.search(f"{name}:" + r"\s*(?P<colour>#[0-9a-f]+);", css)
59
60    if m is None:
61        raise ValueError(f"cannot find variable --{name} in CSS")
62
63    c = m.group("colour")
64
65    # 6- or 8-digit hex colour
66    if len(c) == 7 or len(c) == 9:
67        return c
68
69    # 3-digit hex colour, so double each digit
70    if len(c) == 4:
71        return f"#{c[1] * 2}{c[2] * 2}{c[3] * 2}"
72
73    raise ValueError(f"unrecognised hex string: {c}")
74
75
76if __name__ == "__main__":
77    variable_id, variable_css = get_alexwlchan_net_css("variables.scss")
78    syntax_id, syntax_css = get_alexwlchan_net_css("components/syntax_highlighting.css")
79
80    light_colours: BaseColours = {
81        "background": get_colour_variable(
82            variable_css, name="--background-color-light"
83        ),
84        "text": get_colour_variable(variable_css, name="--body-text-light"),
85        "accent_grey": get_colour_variable(variable_css, name="--accent-grey-light"),
86        "red": get_colour_variable(variable_css, name="--default-primary-color-light"),
87        "green": get_colour_variable(syntax_css, name="--green"),
88        "blue": get_colour_variable(syntax_css, name="--blue"),
89        "magenta": get_colour_variable(syntax_css, name="--magenta"),
90        "yellow": get_colour_variable(syntax_css, name="--yellow"),
91        "highlight": get_colour_variable(syntax_css, name="--highlight"),
92        "cyan": "#38c2ab",
93    }
94
95    # Get the first block of dark theme colours from the syntax highlighting
96    # CSS. This is a bit crude, but it works for now.
97    _, dark_syntax_css = syntax_css.split("@media (prefers-color-scheme: dark) {")
98    dark_colours: BaseColours = {
99        "background": get_colour_variable(variable_css, name="--background-color-dark"),
100        "text": get_colour_variable(variable_css, name="--body-text-dark"),
101        "accent_grey": get_colour_variable(variable_css, name="--accent-grey-dark"),
102        "red": get_colour_variable(variable_css, name="--default-primary-color-dark"),
103        "green": get_colour_variable(dark_syntax_css, name="--green"),
104        "blue": get_colour_variable(dark_syntax_css, name="--blue"),
105        "magenta": get_colour_variable(dark_syntax_css, name="--magenta"),
106        "yellow": get_colour_variable(dark_syntax_css, name="--yellow"),
107        "highlight": get_colour_variable(dark_syntax_css, name="--highlight"),
108        "cyan": "#4ee6d6",
109    }
110
111    # When I do <mark> highlights on my blog, I keep the text black in
112    # dark mode, but for my themes, use a more muted yellow.
113    if dark_colours["highlight"] == "#fffc42cc":
114        dark_colours["highlight"] = "#fffc4244"
115    else:
116        raise ValueError(f"Unrecognised dark colour: {dark_colours['highlight']}")
117
118    palette: BasePalette = {
119        "id": f"{variable_id}-{syntax_id}",
120        "light": light_colours,
121        "dark": dark_colours,
122    }
123
124    with open("palette.json", "w") as out_file:
125        out_file.write(json.dumps(palette, indent=2))
126
127    print(f"Written palette {palette['id']} to palette.json")