#!/usr/bin/env bash
# Rebuilds androidApp/src/main/res/font/nerd_icons.ttf.
#
# The app draws a handful of icons -- a cog, a refresh arrow, send, stop --
# as text in a Nerd Fonts glyph rather than as vector assets or as ordinary
# Unicode. Unicode has no character for most of these, and the ones it does
# have are not reliably in an Android system font, so they land as tofu
# boxes on somebody's phone. Shipping the subset removes the hope: the
# glyph is in the APK.
#
# The whole symbols font is 3 MB for the handful below, so what is
# committed is a subset. Add a codepoint to GLYPHS below and to NerdIcons.kt
# (the two lists have to agree -- a codepoint in the Kotlin but not here is
# a glyph that silently doesn't exist), then run this and commit the result.
#
# Needs python3 and network access; fontTools is fetched into a temporary
# venv, so nothing has to be installed on the machine.
#
# Copied from dev-updater's script of the same name rather than shared
# through wg-app-link, for the reason Theme.kt gives about the palette: the
# link is the tunnel, the pinned CA and enrollment, and an icon set is a
# preference rather than part of that contract.
set -euo pipefail

# Codepoint, then the Nerd Fonts glyph name it came from. Material Design
# Icons bar one, so they read as one family -- and the first two are
# deliberately the same two dev-updater uses, since a cog and a refresh
# arrow mean the same thing in both apps. The exception is noted on its
# own line, as dev-updater's script does with its two.
GLYPHS=(
    U+F0493  # md-cog
    U+F0450  # md-refresh
    U+F048A  # md-send
    U+F04DB  # md-stop
    U+F1163  # md-send_clock
    U+F0156  # md-close
    U+F004D  # md-arrow_left
    U+F201   # fa-line_chart -- Font Awesome's, asked for by name
)

url=https://github.com/ryanoasis/nerd-fonts/releases/latest/download/NerdFontsSymbolsOnly.zip
out="$(cd "$(dirname "$0")" && pwd)/androidApp/src/main/res/font/nerd_icons.ttf"
work="$(mktemp -d)"
trap 'rm -rf "$work"' EXIT

echo "Fetching $url"
curl -fsSL -o "$work/nf.zip" "$url"
python3 -c 'import sys,zipfile; zipfile.ZipFile(sys.argv[1]).extractall(sys.argv[2])' "$work/nf.zip" "$work"

python3 -m venv "$work/venv"
"$work/venv/bin/pip" -q install fonttools

unicodes="$(IFS=,; echo "${GLYPHS[*]}")"
mkdir -p "$(dirname "$out")"
# The proportional face rather than the Mono one: these are drawn inline
# beside text, where a fixed advance would pad each icon out to a cell.
"$work/venv/bin/pyftsubset" "$work/SymbolsNerdFont-Regular.ttf" \
    --unicodes="$unicodes" \
    --layout-features= \
    --drop-tables+=DSIG \
    --output-file="$out"

echo "Wrote $out ($(stat -c %s "$out") bytes) with ${#GLYPHS[@]} glyphs"