#! /bin/bash

set -e

SOCK="$HOME/.xlaunch.sock"
SESSION='xlaunch'
TMUX="tmux -S $SOCK"
LOG_FILE=~/var/log/xlaunch.log

log() {
    local -r fmt="$1"
    shift

    printf "${fmt}\n" $@ | twrap.sh >> "$LOG_FILE"
}

counter_next() {
    local -r file="$_counter_file"

    awk '{n = $1} END {print n + 1}' "$file" | sponge "$file"
    cat "$file"
}

tmux_new_win() {
    local -r command="$1"
    local -r window_id=$(counter_next)
    local -r window_name=$(basename "$command")
    local -r pane=0

    log \
        '[debug] tmux window_id:"%s", window_name:"%s", command:"%s"' \
        "$window_id" "$window_name" "$command"

    $TMUX new-window -t "$SESSION" -n "$window_name"
    $TMUX send-keys  -t "$SESSION":"$window_id"."$pane" "$command" ENTER
}

launch_from_directory() {
    local -r scripts_dir="$1"

    log '[info] Looking for scripts in directory: "%s"' "$scripts_dir"
    if test -d "$scripts_dir"
    then
        for script in "$scripts_dir"/*; do
            log '[debug] Launching script: "%s"' "$script"
            tmux_new_win "$script"
            sleep 0.1 # TODO Find a way to block between starts instead.
        done
    else
        log '[warning] Directory not found: %s' "$scripts_dir"
    fi
}

_start() {
    $TMUX new-session -d -s "$SESSION"
    $TMUX set-option -gt "$SESSION" allow-rename off

    _counter_file=$(mktemp)
    launch_from_directory ~/.xlaunch.d
    launch_from_directory ~/.xlaunch.d."$(hostname)"
}

_startx() {
    log '[info] Starting X11'
    _restart
    log '[info] Launching dwm'
    exec dwm
}

_stop() {
    $TMUX kill-session -t "$SESSION"
}

_restart() {
    _stop || true
    _start
}

_attach() {
    $TMUX attach -t "$SESSION"
}

main() {
    local -r command="$1"

    case "$command" in
        #'' ) _startx;;
        'startx'  ) _startx;;
        'start'   ) _start;;
        'stop'    ) _stop;;
        'restart' ) _restart;;
        'attach'  ) _attach;;
        *)
            echo "[error] Unknown command: \"$command\". Known: startx, start, stop, restart, attach."
            exit 1;;
    esac
}

main "$*"