blomarchy/bin/blob-theme-set

#!/bin/bash

# blob:summary=Apply an Blob theme
# blob:args=<theme-name>
# blob:examples=blob theme list | blob theme set "Tokyo Night"

if [[ -z $1 ]]; then
  echo "Usage: blob-theme-set <theme-name>"
  exit 1
fi

CURRENT_THEME_PATH="$HOME/.local/state/blob/current/theme"
NEXT_THEME_PATH="$HOME/.local/state/blob/current/next-theme"
CURRENT_BACKGROUND_LINK="$HOME/.local/state/blob/current/background"
BACKGROUND_TRANSITION_CACHE="$HOME/.cache/blob/background-transitions"
THEME_SET_LOCK="${XDG_RUNTIME_DIR:-/tmp}/blob-theme-set.lock"
USER_THEMES_PATH="$HOME/.config/blob/themes"
BLOB_THEMES_PATH="$BLOB_PATH/themes"

# What a theme installed from a git repo may not ship, because these run code.
# Hyprland requires a theme's hyprland.lua at login and Neovim loads its
# neovim.lua at startup, so no .lua from such a theme is staged at all. Each
# terminal config names the program the terminal launches. vscode.json is denied
# even though nothing here reads it, because a theme that ships one is naming a
# VS Code extension, which is arbitrary JavaScript. Everything else a theme
# ships is colour and is kept.
#
# Adding a template for another terminal, or for another editor that loads Lua,
# means adding it here.
INSTALLED_THEME_DENIED=(alacritty.toml foot.ini ghostty.conf kitty.conf vscode.json)
IGNORED_THEME_FILES=()

run_parallel() {
  local pid
  local pids=()

  for command in "$@"; do
    bash -lc "$command" &
    pids+=("$!")
  done

  for pid in "${pids[@]}"; do
    wait "$pid"
  done
}

shell_ipc() {
  timeout 2 blob-shell "$@" >/dev/null 2>&1
}

snapshot_background_path() {
  local background="$1"
  local name="$2"
  local snapshot extension

  [[ -f $background ]] || return

  mkdir -p "$BACKGROUND_TRANSITION_CACHE"
  extension=${background##*.}
  snapshot="$BACKGROUND_TRANSITION_CACHE/$name-$$.$extension"
  ln "$background" "$snapshot" 2>/dev/null || cp "$background" "$snapshot"
  echo "$snapshot"
}

snapshot_current_background() {
  local current_background

  current_background=$(readlink -f "$CURRENT_BACKGROUND_LINK" 2>/dev/null || true)
  snapshot_background_path "$current_background" "previous"
}

choose_theme_background() {
  local backgrounds=()
  local current_background index next_index i

  CHOSEN_THEME_BACKGROUND=""
  mapfile -d '' -t backgrounds < <(
    find -L "$HOME/.config/blob/backgrounds/$THEME_NAME/" "$CURRENT_THEME_PATH/backgrounds/" -maxdepth 1 -type f \
      \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' -o -iname '*.gif' -o -iname '*.bmp' -o -iname '*.webp' \) \
      -print0 2>/dev/null | sort -z
  )

  (( ${#backgrounds[@]} > 0 )) || return 1

  current_background=$(readlink "$CURRENT_BACKGROUND_LINK" 2>/dev/null || true)
  index=-1
  for i in "${!backgrounds[@]}"; do
    if [[ ${backgrounds[$i]} == $current_background ]]; then
      index=$i
      break
    fi
  done

  if (( index == -1 )); then
    CHOSEN_THEME_BACKGROUND="${backgrounds[0]}"
  else
    next_index=$(((index + 1) % ${#backgrounds[@]}))
    CHOSEN_THEME_BACKGROUND="${backgrounds[$next_index]}"
  fi
}

set_theme_background_link() {
  choose_theme_background || return 1
  ln -nsf "$CHOSEN_THEME_BACKGROUND" "$CURRENT_BACKGROUND_LINK"
}

set_theme_background() {
  local new_background new_background_snapshot

  if ! choose_theme_background; then
    shell_ipc shell applyTheme "$colors_payload" "$shell_payload" || true
    return
  fi

  new_background="$CHOSEN_THEME_BACKGROUND"
  new_background_snapshot=$(snapshot_background_path "$new_background" "next")

  if [[ -f $OLD_BACKGROUND_SNAPSHOT && -f $new_background_snapshot ]]; then
    shell_ipc background themeTransition "$OLD_BACKGROUND_SNAPSHOT" "$new_background_snapshot" "$new_background" "$colors_payload" "$shell_payload" || \
      shell_ipc shell applyTheme "$colors_payload" "$shell_payload" || true
    (sleep 3; rm -f "$OLD_BACKGROUND_SNAPSHOT" "$new_background_snapshot") &
  elif [[ -f $new_background_snapshot ]]; then
    shell_ipc background themeTransition "" "$new_background_snapshot" "$new_background" "$colors_payload" "$shell_payload" || \
      shell_ipc shell applyTheme "$colors_payload" "$shell_payload" || true
    (sleep 3; rm -f "$new_background_snapshot") &
  else
    shell_ipc background themeTransition "$OLD_BACKGROUND_SNAPSHOT" "$new_background" "$new_background" "$colors_payload" "$shell_payload" || \
      shell_ipc shell applyTheme "$colors_payload" "$shell_payload" || true
    if [[ -f $OLD_BACKGROUND_SNAPSHOT ]]; then
      (sleep 3; rm -f "$OLD_BACKGROUND_SNAPSHOT") &
    fi
  fi

  ln -nsf "$new_background" "$CURRENT_BACKGROUND_LINK"
}

is_denied_installed_file() {
  local name="$1"
  local denied

  [[ $name == *.lua ]] && return 0

  for denied in "${INSTALLED_THEME_DENIED[@]}"; do
    [[ $name == "$denied" ]] && return 0
  done

  return 1
}

# Themes older than colors.toml still get their palette, but their
# alacritty.toml never reaches the staged theme: an Alacritty config names the
# program the terminal launches.
stage_installed_colors_from_alacritty() {
  local source="$1"
  local scratch

  if [[ -f $NEXT_THEME_PATH/colors.toml ]]; then
    return
  fi

  if [[ ! -f $source/alacritty.toml || -L $source/alacritty.toml ]]; then
    return
  fi

  scratch=$(mktemp -d)
  cp "$source/alacritty.toml" "$scratch/alacritty.toml"
  blob-theme-import "$scratch"

  if [[ -f $scratch/colors.toml ]]; then
    cp "$scratch/colors.toml" "$NEXT_THEME_PATH/colors.toml"
  fi

  rm -rf "$scratch"
}

# Copies a directory without ever following a symlink: in an installed theme one
# points wherever the theme author chose, which is how an unlock.png becomes a
# copy of any file the session can read.
stage_installed_dir() {
  local source="$1"
  local dest="$2"
  local entry name

  mkdir -p "$dest"

  for entry in "$source"/*; do
    [[ -e $entry && ! -L $entry ]] || continue
    name=${entry##*/}

    if [[ -d $entry ]]; then
      stage_installed_dir "$entry" "$dest/$name"
    else
      cp "$entry" "$dest/$name"
    fi
  done
}

# `blob theme install` clones into ~/.config/blob/themes, so a .git
# directory there means the contents came from a stranger and are held to the
# list above. A directory the user wrote themselves, and a symlink to their own
# working copy, are theirs to fill however they like -- the same distinction
# blob-theme-extras draws when it decides which themes it may pull.
theme_came_from_a_repo() {
  local source="$1"

  [[ ! -L $source && -d $source/.git ]]
}

stage_installed_theme() {
  local source="$1"
  local entry name

  [[ -d $source ]] || return 0

  for entry in "$source"/*; do
    [[ -e $entry ]] || continue
    name=${entry##*/}

    if [[ -L $entry ]] || is_denied_installed_file "$name"; then
      case "${name,,}" in
        readme* | license* | changelog* | *.md | *.txt) ;;
        *) IGNORED_THEME_FILES+=("$name") ;;
      esac
    elif [[ -d $entry ]]; then
      stage_installed_dir "$entry" "$NEXT_THEME_PATH/$name"
    else
      cp "$entry" "$NEXT_THEME_PATH/$name"
    fi
  done

  stage_installed_colors_from_alacritty "$source"
}

report_ignored_theme_files() {
  (( ${#IGNORED_THEME_FILES[@]} > 0 )) || return 0

  echo "Ignored in $USER_THEMES_PATH/$THEME_NAME: ${IGNORED_THEME_FILES[*]}" >&2
  echo "A theme installed from a git repo cannot supply Lua, a terminal config, or vscode.json." >&2
}

THEME_NAME=$(echo "$1" | sed -E 's/<[^>]+>//g' | tr '[:upper:]' '[:lower:]' | tr ' ' '-')
THEME_HEADLESS=0
if [[ ${BLOB_THEME_HEADLESS:-} == "1" || ${BLOB_THEME_OFFLINE:-} == "1" ]]; then
  THEME_HEADLESS=1
fi

if [[ -z $THEME_NAME || $THEME_NAME == .* || $THEME_NAME == */* ]]; then
  echo "Invalid theme name: $1"
  exit 1
fi

if [[ ! -d $BLOB_THEMES_PATH/$THEME_NAME ]] && [[ ! -d $USER_THEMES_PATH/$THEME_NAME ]]; then
  echo "Theme '$THEME_NAME' does not exist"
  exit 1
fi

# Serialize theme changes. Theme switching rebuilds a shared next-theme staging
# directory and updates current theme/background symlinks; concurrent calls can
# otherwise race and make one selection appear to be ignored.
exec 9>"$THEME_SET_LOCK"
flock 9

# Setup clean next theme directory (for atomic theme config swapping)
rm -rf "$NEXT_THEME_PATH"
mkdir -p "$NEXT_THEME_PATH"

# Copy official theme first, then overlay the user's theme on top
cp -r "$BLOB_THEMES_PATH/$THEME_NAME/"* "$NEXT_THEME_PATH/" 2>/dev/null

if theme_came_from_a_repo "$USER_THEMES_PATH/$THEME_NAME"; then
  stage_installed_theme "$USER_THEMES_PATH/$THEME_NAME"
  report_ignored_theme_files
else
  cp -r "$USER_THEMES_PATH/$THEME_NAME/"* "$NEXT_THEME_PATH/" 2>/dev/null
fi

# Generate colors.toml from alacritty.toml if theme is missing colors.toml
if [[ ! -f $NEXT_THEME_PATH/colors.toml && -f $NEXT_THEME_PATH/alacritty.toml ]]; then
  blob-theme-import "$NEXT_THEME_PATH"
fi

# Generate dynamic configs
blob-theme-templates

OLD_BACKGROUND_SNAPSHOT=""
if [[ $THEME_HEADLESS != "1" && $BLOB_THEME_SKIP_BACKGROUND != "1" ]]; then
  OLD_BACKGROUND_SNAPSHOT=$(snapshot_current_background)
fi

# Swap next theme in as current
rm -rf "$CURRENT_THEME_PATH"
mv "$NEXT_THEME_PATH" "$CURRENT_THEME_PATH"

# Store theme name for reference
echo "$THEME_NAME" >"$HOME/.local/state/blob/current/theme.name"

# Make the running shell pick up the new palette immediately while the rest of
# the theme hooks run.
colors_payload=$([[ -f $CURRENT_THEME_PATH/colors.toml ]] && base64 -w 0 "$CURRENT_THEME_PATH/colors.toml")
shell_payload=$([[ -f $CURRENT_THEME_PATH/shell.toml ]] && base64 -w 0 "$CURRENT_THEME_PATH/shell.toml")
if [[ $THEME_HEADLESS == "1" ]]; then
  # No shell/session bus exists during ISO chroot finalization, but the first
  # real login still needs a current background symlink for blob-shell to
  # render.
  [[ $BLOB_THEME_SKIP_BACKGROUND == "1" ]] || set_theme_background_link || true
elif [[ $BLOB_THEME_SKIP_BACKGROUND == "1" ]]; then
  shell_ipc shell applyTheme "$colors_payload" "$shell_payload" || true
else
  set_theme_background
fi

# The shared staging/current symlinks are updated and the shell has accepted
# the transition. Let another theme selection queue only behind that critical
# section, not behind slower app-retint hooks and selector cache warmups.
flock -u 9

post_theme_commands=(
  blob-restart-terminal
  blob-hypr-restart
  blob-restart-btop
  blob-theme-foot
  blob-theme-browser
  blob-theme-gtk
)

if [[ $THEME_HEADLESS != "1" ]]; then
  run_parallel "${post_theme_commands[@]}"

  # Call hook on theme set
  blob-hook theme-set "$THEME_NAME" >/dev/null

  # Warm selector caches after the theme is applied. The shell hot-reloads theme
  # colors/backgrounds, so keep the running instance alive and preload the picker
  # rows/selection to avoid first-open carousel settling after a theme change.
  blob-theme-switcher --preload >/dev/null 2>&1
  blob-bg-cache >/dev/null 2>&1 &
fi