#!/bin/sh
# Shows the key cheat sheet (Esc closes it). Written by Wren Linux install-base.sh
# data/keys.txt has blocks "@if COMMAND" ... "@end": a block is shown only if
# COMMAND is installed, so the sheet lists just what this computer has. It is
# written with Super as sway's key; when your sway config uses Alt instead
# (set $mod Mod1), every Super shows as Alt.
#   keys                the pager of the Wren menu when that is installed; less otherwise
#   keys --text         the sheet as plain text on standard output
#   keys --mod alt      sway's shortcuts use Alt (keys --mod super: the Windows key)
#   keys --welcome      the first login: asks which key, then shows the sheet
SHEET=$HOME/.local/share/wren/keys.txt
SWAY_CONFIG=$HOME/.config/sway/config
# on a text console (the same test as tmux's console.conf) the sheet for tmux
CONSOLE_SHEET=$HOME/.local/share/wren/keys-console.txt
CONSOLE=
if [ -z "${WAYLAND_DISPLAY:-}" ] && [ -f "$CONSOLE_SHEET" ]; then
    CONSOLE=1
    SHEET=$CONSOLE_SHEET
fi

# mod: Alt or Super, from the set $mod line of your sway config
mod() {
    # shellcheck disable=SC2016  # $mod is sway's variable, not the shell's
    if grep -qE '^[[:space:]]*set[[:space:]]+\$mod[[:space:]]+Mod1[[:space:]]*$' "$SWAY_CONFIG" 2>/dev/null; then
        echo Alt
    else
        echo Super
    fi
}

# text: the sheet without the blocks of commands that are not installed, with
# sway's key as it is set
text() {
    awk -v mod="$(mod)" '
        /^@if / { skip = (system("command -v " $2 " >/dev/null 2>&1") != 0); next }
        /^@unless / { f = $2; sub(/^~/, ENVIRON["HOME"], f); skip = (system("test -e \"" f "\"") == 0); next }
        /^@end/ { skip = 0; next }
        skip { next }
        mod == "Alt" {
            sub(/Super = the Windows \/ Cmd key/, "Alt = sway'"'"'s key (keys --mod super: the Windows key)")
            gsub(/Super/, "Alt")
        }
        { print }'  "$SHEET"
}

# set_mod super|alt: the set $mod line of your sway config, checked by sway first
set_mod() {
    case $1 in
        super) want=Mod4 name=Super ;;
        alt) want=Mod1 name=Alt ;;
        *) echo "usage: keys --mod super|alt" >&2; return 2 ;;
    esac
    # shellcheck disable=SC2016  # $mod is sway's variable, not the shell's
    if ! grep -qE '^[[:space:]]*set[[:space:]]+\$mod[[:space:]]+Mod[14][[:space:]]*$' "$SWAY_CONFIG" 2>/dev/null; then
        echo "keys: $SWAY_CONFIG has no 'set \$mod Mod4' (or Mod1) line, so it was left alone." >&2
        return 1
    fi
    new=$(mktemp) || return 1
    sed -E "s/^([[:space:]]*set[[:space:]]+\\\$mod[[:space:]]+)Mod[14]([[:space:]]*)\$/\\1$want\\2/" "$SWAY_CONFIG" >"$new"
    if command -v sway >/dev/null; then
        out=$(WLR_BACKENDS=headless WLR_RENDERER=pixman WLR_LIBINPUT_NO_DEVICES=1 sway -C -c "$new" 2>&1 || true)
        if printf '%s\n' "$out" | grep -q '\[ERROR\]'; then
            rm -f "$new"
            echo "keys: sway rejected the change, so nothing was changed: $(printf '%s\n' "$out" | grep -m1 '\[ERROR\]')" >&2
            return 1
        fi
    fi
    cat "$new" >"$SWAY_CONFIG"
    rm -f "$new"
    if [ -n "${SWAYSOCK:-}" ] && command -v swaymsg >/dev/null; then swaymsg reload >/dev/null 2>&1; fi
    echo "sway's shortcuts now start with $name ($name+d opens the launcher, $name+Enter a terminal); keys shows them that way."
}

# welcome: which key, the first time sway starts (bin/wren-welcome)
welcome() {
    cat <<'EOF'

  Welcome to Wren Linux.

  sway's shortcuts all start with one key. Which one do you want?

    1) Super, the Windows / Cmd key (the usual one)
    2) Alt (handy on a keyboard without a Windows key; programs then don't get
       their own Alt shortcuts that sway uses, such as Alt+d or Alt+1 in Firefox)

  Change it any time: keys --mod alt   or   keys --mod super

EOF
    printf '  1 or 2 (Enter for Super): '
    read -r answer || answer=
    case $answer in
        2 | [aA]*) set_mod alt ;;
        *) [ "$(mod)" = Super ] || set_mod super ;;
    esac
    printf '  Press Enter for the list of keys. '
    read -r _ || true
}

case ${1:-} in
    --text) text; exit ;;
    --mod) set_mod "${2:-}"; exit ;;
    --welcome) welcome ;;
esac

shown=$(mktemp) || exit 1
trap 'rm -f "$shown"' EXIT
text >"$shown"
# ~/KEYS.txt follows along (only if it is the link or copy Wren Linux made)
if [ -z "$CONSOLE" ] && { [ ! -e "$HOME/KEYS.txt" ] || [ -L "$HOME/KEYS.txt" ] || grep -q 'Super = the Windows' "$HOME/KEYS.txt" 2>/dev/null ||
    grep -q "Alt = sway's key" "$HOME/KEYS.txt" 2>/dev/null; }; then
    rm -f "$HOME/KEYS.txt"
    cp "$shown" "$HOME/KEYS.txt" 2>/dev/null
fi
if [ -x "$HOME/.local/bin/wren-menu" ]; then "$HOME/.local/bin/wren-menu" --pager "$shown"; else less "$shown"; fi