#!/usr/bin/env bash
set -euo pipefail

# Runs inside the sandbox as ai-sbx-workspace. The caller must start it from a
# login shell: the tmux server inherits this process's environment, so PATH, the
# mise shims, the AWS credentials and every secret placeholder reach all three
# windows through it. A non-login shell here loses the lot, and the symptom is
# "npm cannot authenticate" rather than anything that points at tmux.

SESSION=ai-sbx

# The claude invocation is observed, not assumed: sampling the process table of
# a sandbox attached with "sbx run" shows this exact command line. Getting it
# wrong would silently change the agent's permission model, so agents whose
# invocation has not been observed fall back to the bare name.
agent_command() {
    case "$1" in
        claude)
            printf '%s' 'claude --dangerously-skip-permissions'
            ;;
        *)
            printf '%s' "$1"
            ;;
    esac
}

main() {
    local agent="${1:-claude}"
    local agent_cmd
    agent_cmd="$(agent_command "$agent")"

    if ! command -v tmux >/dev/null 2>&1; then
        printf '%s\n' \
            'tmux is not installed in this sandbox; starting the agent directly.' \
            '' \
            'Add tmux to AI_SBX_TOOLS, or use a custom image that carries it:' \
            '' \
            '  AI_SBX_TOOLS = "bun tmux neovim"' \
            '' >&2
        # Deliberate word splitting: the command comes from the mapping above.
        # shellcheck disable=SC2086
        exec $agent_cmd
    fi

    # Attach-or-create. Detaching and re-running must land back in the same
    # session with the agent's context intact, which is most of the point.
    if tmux has-session -t "$SESSION" 2>/dev/null; then
        exec tmux attach-session -t "$SESSION"
    fi

    tmux new-session -d -s "$SESSION" -n agent -c "$PWD"
    tmux new-window -t "$SESSION:" -n edit -c "$PWD"
    tmux new-window -t "$SESSION:" -n shell -c "$PWD"

    tmux send-keys -t "$SESSION:agent" "$agent_cmd" C-m
    tmux send-keys -t "$SESSION:edit" 'nvim .' C-m

    tmux select-window -t "$SESSION:agent"
    exec tmux attach-session -t "$SESSION"
}

main "$@"