lnbits-sensei/modules/dev-env/scripts/tmux-launch.sh

#!/usr/bin/env bash
# dev-tm: launch a declared tmux session
#
# Reads /etc/dev-env/tmux-sessions.json (rendered by config.nix) and
# either attaches to an existing session or creates one with the
# declared windows. Window cwds are resolved relative to $DEV_ROOT.
#
# This is a single generic launcher; the window layouts come from Nix
# (or a runtime override at ~/.config/dev-env/tmux-sessions.json).

set -euo pipefail

if [[ -r /etc/dev-env/config.sh ]]; then
    # shellcheck disable=SC1091
    source /etc/dev-env/config.sh
fi

DEV_ROOT="${DEV_ROOT:-$HOME/dev}"

# Prefer a user override if present
SESSIONS_JSON=""
if [[ -r "$HOME/.config/dev-env/tmux-sessions.json" ]]; then
    SESSIONS_JSON="$HOME/.config/dev-env/tmux-sessions.json"
elif [[ -r /etc/dev-env/tmux-sessions.json ]]; then
    SESSIONS_JSON=/etc/dev-env/tmux-sessions.json
else
    echo "No tmux-sessions.json found" >&2
    exit 1
fi

usage() {
    cat <<EOF
dev-tm — declarative tmux session launcher

USAGE:
  dev-tm                   list available sessions
  dev-tm <session>         start or attach to <session>
  dev-tm -k <session>      kill session
  dev-tm -k all            kill all dev sessions
  dev-tm -l                list available sessions
EOF
}

list_sessions() {
    echo "Defined sessions (from $SESSIONS_JSON):"
    jq -r 'keys[]' "$SESSIONS_JSON" | sed 's/^/  /'
    echo ""
    echo "Active tmux sessions:"
    tmux list-sessions 2>/dev/null | sed 's/^/  /' || echo "  (none)"
}

resolve_path() {
    local p="$1"
    [[ -z "$p" || "$p" == "null" ]] && { echo "$DEV_ROOT"; return; }
    [[ "$p" = /* ]] && { echo "$p"; return; }
    echo "$DEV_ROOT/$p"
}

start_session() {
    local name="$1"
    local session_name="dev-$name"

    if tmux has-session -t "$session_name" 2>/dev/null; then
        tmux attach-session -t "$session_name"
        return
    fi

    local session_cwd
    session_cwd="$(resolve_path "$(jq -r --arg s "$name" '.[$s].cwd // empty' "$SESSIONS_JSON")")"

    local nwindows
    nwindows="$(jq --arg s "$name" '.[$s].windows | length' "$SESSIONS_JSON")"
    if (( nwindows == 0 )); then
        echo "Session '$name' has no windows defined" >&2
        exit 1
    fi

    # First window
    local first_name first_cwd first_cmd
    first_name="$(jq -r --arg s "$name" '.[$s].windows[0].name' "$SESSIONS_JSON")"
    first_cwd="$(resolve_path "$(jq -r --arg s "$name" '.[$s].windows[0].cwd // empty' "$SESSIONS_JSON")")"
    first_cmd="$(jq -r --arg s "$name" '.[$s].windows[0].cmd // empty' "$SESSIONS_JSON")"

    tmux new-session -d -s "$session_name" -n "$first_name" -c "$first_cwd"
    [[ -n "$first_cmd" && "$first_cmd" != "null" ]] && \
        tmux send-keys -t "$session_name:0" "$first_cmd" C-m

    # Remaining windows
    for ((i = 1; i < nwindows; i++)); do
        local wn wcwd wcmd
        wn="$(jq -r --arg s "$name" --argjson i "$i" '.[$s].windows[$i].name' "$SESSIONS_JSON")"
        wcwd="$(resolve_path "$(jq -r --arg s "$name" --argjson i "$i" '.[$s].windows[$i].cwd // empty' "$SESSIONS_JSON")")"
        wcmd="$(jq -r --arg s "$name" --argjson i "$i" '.[$s].windows[$i].cmd // empty' "$SESSIONS_JSON")"
        tmux new-window -t "$session_name" -n "$wn" -c "$wcwd"
        [[ -n "$wcmd" && "$wcmd" != "null" ]] && \
            tmux send-keys -t "$session_name:$i" "$wcmd" C-m
    done

    tmux select-window -t "$session_name:0"
    tmux attach-session -t "$session_name"
}

kill_session() {
    local target="$1"
    if [[ "$target" == "all" ]]; then
        tmux list-sessions -F '#{session_name}' 2>/dev/null \
            | grep '^dev-' \
            | xargs -r -n1 tmux kill-session -t \
            || echo "No dev sessions to kill"
        return
    fi
    tmux kill-session -t "dev-$target" 2>/dev/null || echo "Session 'dev-$target' not found"
}

# --- entry ---
case "${1:-}" in
    -h|--help) usage ;;
    -l|--list|"") list_sessions ;;
    -k|--kill)
        [[ -z "${2:-}" ]] && { echo "Usage: dev-tm -k <session|all>"; exit 1; }
        kill_session "$2"
        ;;
    *)
        if ! jq -e --arg s "$1" 'has($s)' "$SESSIONS_JSON" >/dev/null; then
            echo "Unknown session: $1" >&2
            list_sessions
            exit 1
        fi
        start_session "$1"
        ;;
esac