'''
Generates the `ExternalFontFamily` definitions used in `app/src/font_fallback.rs`.
These definitions contain the URLs to each external fallback font we use in Warp.
Generated code is sent to stdout.

This script will read our cloud storage bucket to retrieve the names of the fonts
we support, and generate the code required to initialize static references for
each font family.

Assumes that the fallback fonts in the prod `warp-static-assets` bucket are
identical to the ones stored in the staging `warp-server-staging-static-assets`
bucket.

Usage:
1. Make sure the gcloud CLI is installed and you are authed via `gcloud auth login`.
2. Run `python3 generate_families.py`
3. Manually inspect the name for each font. The script will generate the name in
   title-case, but this isn't correct for some fonts (e.g. Noto Sans SC).
'''

import subprocess
from collections import defaultdict


def list_fonts():
    command = "gcloud storage ls --recursive 'gs://warp-static-assets/fallback-fonts/**.ttf'"
    return subprocess.check_output(command, shell=True, text=True).splitlines()


def generate_families(font_uris):
    family_map = defaultdict(list)
    for uri in font_uris:
        parts = uri.removeprefix("gs://warp-static-assets/fallback-fonts/").split('/')
        family_name = parts[0]
        font_name = parts[1]
        family_map[family_name].append(font_name)

    for family_name, font_names in family_map.items():
        print_family(family_name, font_names)


def indent_level(level, s):
    indent = "    " * level
    return indent + s


def print_family(family_name, font_names):
    variable_name = family_name.replace('-', '_').upper()
    title_case_name = family_name.replace('-', ' ').title()

    print(f"static ref {variable_name}: ExternalFontFamily = ExternalFontFamily {{")
    # Title-case is not correct for some fonts, e.g. "Noto Sans SC", so we add
    # a todo to make any manual adjustments.
    print(indent_level(1, f"name: \"{title_case_name}\", // TODO: double-check the title is correct"))
    print(indent_level(1, "font_urls: Arc::new(vec!["))
    for font_name in font_names:
        print(indent_level(2, f"url_for_font(\"{family_name}\", \"{font_name}\"),"))
    print(indent_level(1, "]),"))
    print("};")


def main():
    font_uris = list_fonts()
    generate_families(font_uris)


if __name__ == "__main__":
    main()