#!/usr/bin/env bash
# rice-theme - render and apply a colour theme to every surface of the rice.
#
#   rice-theme set <name>     render themes/<name> and reload everything
#   rice-theme select         open the visual theme selector
#   rice-theme reload         re-render the current theme (after editing a template)
#   rice-theme list           available themes
#   rice-theme current        name of the active theme
#   rice-theme get <key>      one value from the active colors.toml (for scripts)
#
# Templates live in $RICE_DIR/templates/*.tpl and ~/.config/rice/templates/*.tpl
# (yours win). Placeholders, for a key like  accent = "#92b9ea":
#   {{ accent }}        #92b9ea
#   {{ accent_strip }}  92b9ea
#   {{ accent_rgb }}    146,185,234
# A theme can ship a finished file (e.g. themes/foo/btop.theme); it is used
# as-is instead of the template with the same output name.
set -euo pipefail

RICE_DIR="${RICE_DIR:-$(cd "$(dirname "$(readlink -f "$0")")/.." && pwd)}"
STATE="${XDG_STATE_HOME:-$HOME/.local/state}/rice"
CURRENT="$STATE/theme"
USER_TEMPLATES="${XDG_CONFIG_HOME:-$HOME/.config}/rice/templates"
HOOKS="${XDG_CONFIG_HOME:-$HOME/.config}/rice/hooks/theme-set.d"
OVERRIDE="${XDG_CONFIG_HOME:-$HOME/.config}/rice/theme.override.toml"

die() { printf 'rice-theme: %s\n' "$*" >&2; exit 1; }

theme_dir() {
  local user="${XDG_CONFIG_HOME:-$HOME/.config}/rice/themes/$1"
  if [[ -d $user ]]; then echo "$user"
  elif [[ -d $RICE_DIR/themes/$1 ]]; then echo "$RICE_DIR/themes/$1"
  else return 1; fi
}

# Emit "key<TAB>value" for every  key = value  line of a colors.toml.
# Quoted values are taken whole (a colour's # is not a comment); bare values
# stop at a trailing # comment.
parse_colors() {
  sed -n -E \
    -e 's/^[[:space:]]*([a-z_][a-z0-9_]*)[[:space:]]*=[[:space:]]*"([^"]*)".*$/\1\t\2/p' \
    -e 't' \
    -e 's/^[[:space:]]*([a-z_][a-z0-9_]*)[[:space:]]*=[[:space:]]*([^"#[:space:]]([^#]*[^#[:space:]])?)[[:space:]]*(#.*)?$/\1\t\2/p' \
    "$1"
}

# Build a sed program that replaces every placeholder form for every key.
sed_program() {
  local key value esc r g b
  while IFS=$'\t' read -r key value; do
    esc=$(printf '%s' "$value" | sed -e 's/[\\&|]/\\&/g')
    printf 's|{{ *%s *}}|%s|g\n' "$key" "$esc"
    if [[ $value =~ ^#([0-9a-fA-F]{2})([0-9a-fA-F]{2})([0-9a-fA-F]{2})$ ]]; then
      r=$((16#${BASH_REMATCH[1]})); g=$((16#${BASH_REMATCH[2]})); b=$((16#${BASH_REMATCH[3]}))
      printf 's|{{ *%s_strip *}}|%s|g\n' "$key" "${value#\#}"
      printf 's|{{ *%s_rgb *}}|%s,%s,%s|g\n' "$key" "$r" "$g" "$b"
    fi
  done < <(parse_colors "$1" | tac | awk -F'\t' '!seen[$1]++')   # a later line wins (overrides)
}

render() {
  local name="$1" src out next prog tpl base
  src=$(theme_dir "$name") || die "no theme called '$name' (try: rice-theme list)"
  [[ -f $src/colors.toml ]] || die "$src has no colors.toml"

  mkdir -p "$STATE"
  next=$(mktemp -d "$STATE/.theme.XXXXXX")
  cp -a "$src/." "$next/"
  # Your overrides (the font from rice-font, or any colour) apply on top of every theme.
  if [[ -f $OVERRIDE ]]; then
    printf '\n# --- from %s ---\n' "$OVERRIDE" >> "$next/colors.toml"
    cat "$OVERRIDE" >> "$next/colors.toml"
  fi
  prog="$next/.render.sed"
  sed_program "$next/colors.toml" > "$prog"

  # User templates first, so a same-named built-in is skipped.
  for tpl in "$USER_TEMPLATES"/*.tpl "$RICE_DIR"/templates/*.tpl; do
    [[ -f $tpl ]] || continue
    base=$(basename "$tpl" .tpl)
    out="$next/$base"
    [[ -e $out ]] && continue
    sed -f "$prog" "$tpl" > "$out"
    if grep -q '{{' "$out"; then
      printf 'rice-theme: %s has unknown placeholders: %s\n' "$base" \
        "$(grep -o '{{[^}]*}}' "$out" | sort -u | tr '\n' ' ')" >&2
    fi
  done
  rm -f "$prog"

  rm -rf "$CURRENT.old"
  [[ -d $CURRENT ]] && mv "$CURRENT" "$CURRENT.old"
  mv "$next" "$CURRENT"
  rm -rf "$CURRENT.old"
  printf '%s\n' "$name" > "$STATE/theme.name"
}

# signal_if_caught <SIGNAL> <process-name>: send the signal only to processes
# whose SigCgt mask says they install a handler for it.
signal_if_caught() {
  local sig="$1" name="$2" num pid mask
  num=$(kill -l "$sig")
  for pid in $(pgrep -u "$UID" -x "$name"); do
    mask=$(awk '/^SigCgt:/ { print $2 }' "/proc/$pid/status" 2>/dev/null)
    [[ -n $mask ]] && (( (16#$mask >> (num - 1)) & 1 )) && kill -"$sig" "$pid"
  done
  return 0
}

# Push the freshly rendered files into running programs. Each step is
# best-effort: a program that isn't running simply has nothing to reload.
apply() {
  local t="$CURRENT"
  [[ -f $t/bspwm-colors.sh ]] && pgrep -x bspwm >/dev/null && bash "$t/bspwm-colors.sh"
  [[ -f $t/Xresources ]] && command -v xrdb >/dev/null && xrdb -merge "$t/Xresources"
  # One cursor for X, GTK and Qt apps: the default cursor theme follows the rice's.
  local cursor; cursor=$("$0" get cursor_theme 2>/dev/null)
  if [[ -n $cursor ]]; then
    mkdir -p "$HOME/.icons/default"
    printf '[Icon Theme]\nInherits=%s\n' "$cursor" > "$HOME/.icons/default/index.theme"
  fi
  pgrep -x polybar >/dev/null && polybar-msg cmd restart >/dev/null 2>&1 || true
  pgrep -x dunst >/dev/null && dunstctl reload >/dev/null 2>&1 || true
  pgrep -x eww >/dev/null && eww reload >/dev/null 2>&1 || true
  # USR1 makes kitty and the rice's st re-read their colours, but it kills a
  # process that doesn't handle it (an older st build), so check first.
  signal_if_caught USR1 kitty
  signal_if_caught USR1 st
  pgrep -x xsettingsd >/dev/null && pkill -HUP -x xsettingsd || true
  if command -v flameshot >/dev/null; then
    flameshot config --maincolor "$("$0" get accent)" --contrastcolor "$("$0" get bg)" \
      --showhelp false --trayicon false >/dev/null 2>&1 || true
  fi
  if [[ -d $HOOKS ]]; then
    for h in "$HOOKS"/*; do [[ -x $h ]] && "$h" "$(cat "$STATE/theme.name")" || true; done
  fi
}

cmd="${1:-}"
case "$cmd" in
  set)
    [[ -n ${2:-} ]] || die "usage: rice-theme set <name>"
    exec 9>"${XDG_RUNTIME_DIR:-/tmp}/rice-theme.lock"; flock 9
    render "$2"; apply
    # Only a theme change swaps the wallpaper; `reload` keeps the one you picked.
    command -v rice-wallpaper >/dev/null && { rice-wallpaper theme-default >/dev/null 2>&1 || true; }
    command -v notify-send >/dev/null && notify-send -a rice -u low "Theme" "$(grep -m1 '^name' "$CURRENT/colors.toml" | cut -d'"' -f2)" || true
    ;;
  render)
    # Render only, touch no running program (used by install.sh and for testing).
    render "${2:-$(cat "$STATE/theme.name" 2>/dev/null || echo sakura-line)}"
    ;;
  reload)
    exec 9>"${XDG_RUNTIME_DIR:-/tmp}/rice-theme.lock"; flock 9
    render "$(cat "$STATE/theme.name" 2>/dev/null || echo sakura-line)"; apply
    ;;
  select|picker|menu)
    command -v rice-menu >/dev/null && exec rice-menu theme || die "rice-menu not found"
    ;;
  list)
    {
      [[ -d $RICE_DIR/themes ]] && ls -1 "$RICE_DIR/themes" || true
      [[ -d ${XDG_CONFIG_HOME:-$HOME/.config}/rice/themes ]] && ls -1 "${XDG_CONFIG_HOME:-$HOME/.config}/rice/themes" || true
    } 2>/dev/null | sort -u
    ;;
  current)
    cat "$STATE/theme.name" 2>/dev/null || echo sakura-line
    ;;
  get)
    [[ -n ${2:-} ]] || die "usage: rice-theme get <key>"
    parse_colors "$CURRENT/colors.toml" | awk -F'\t' -v k="$2" '$1 == k { v = $2; found = 1 } END { if (found) print v; exit !found }'
    ;;
  *)
    sed -n '2,15p' "$0" | sed 's/^# \{0,1\}//'
    [[ -z $cmd ]] || exit 2
    ;;
esac