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

usage() {
  cat >&2 <<'USAGE'
ai-agent — Codex wrapper with isolated config/home.

Usage:
  ai-agent [--prompt-file FILE] [-i IMAGE]
  ai-agent --help

Options:
  --prompt-file FILE   Read prompt text from FILE; otherwise read stdin.
  -i IMAGE             Attach an image file to the prompt.
  -h, --help           Show this help and exit.

Behavior:
  - Uses a temporary CODEX_HOME with the templates config.toml.
  - Symlinks auth.json from the real CODEX home for credentials.
  - Invokes codex exec and streams Codex output to stdout.
USAGE
}

image=""
prompt_file=""
while [ $# -gt 0 ]; do
  case "$1" in
    -h|--help) usage; exit 0 ;;
    --prompt-file)
      if [ $# -lt 2 ]; then echo "Option --prompt-file requires a path" >&2; exit 2; fi
      prompt_file="$2"; shift 2 ;;
    -i)
      if [ $# -lt 2 ]; then echo "Option -i requires a path" >&2; exit 2; fi
      image="$2"; shift 2 ;;
    *)
      echo "Unknown option: $1" >&2
      usage
      exit 2 ;;
  esac
done

if [ -n "$prompt_file" ] && [ ! -f "$prompt_file" ]; then
  echo "Error: prompt file not found: $prompt_file" >&2
  exit 2
fi

if [ -n "$image" ] && [ ! -f "$image" ]; then
  echo "Error: image file not found: $image" >&2
  exit 2
fi

base_home="${CODEX_HOME:-$HOME/.codex}"
tmp_home=$(mktemp -d "${TMPDIR:-/tmp}/codex-home.XXXXXX") || exit 1
cleanup() { rm -rf "$tmp_home" 2>/dev/null || true; }
trap cleanup EXIT INT TERM

template_config="$HOME/Github/instaboard-pseo/templates/config.toml"
if [ ! -f "$template_config" ]; then
  echo "Error: template config missing at $template_config" >&2
  exit 1
fi
if ! cp "$template_config" "$tmp_home/config.toml" >/dev/null 2>&1; then
  echo "Error: failed to copy config to $tmp_home" >&2
  exit 1
fi

if [ -f "$base_home/auth.json" ]; then
  ln -s "$base_home/auth.json" "$tmp_home/auth.json" 2>/dev/null || true
fi

CODEX_BIN="/opt/homebrew/bin/codex"
if [ ! -x "$CODEX_BIN" ]; then
  echo "Error: codex CLI not found at $CODEX_BIN" >&2
  exit 127
fi

cmd=(env CODEX_HOME="$tmp_home" "$CODEX_BIN" exec)
if [ -n "$image" ]; then
  image_path=$(realpath "$image")
  cmd=(-i "$image_path" "${cmd[@]}")
fi

# Read prompt
if [ -n "$prompt_file" ]; then
  prompt_content=$(cat "$prompt_file")
else
  prompt_content=$(cat)
fi

if [ -z "$prompt_content" ]; then
  echo "Error: prompt is empty" >&2
  exit 2
fi

if ! printf '%s' "$prompt_content" | "${cmd[@]}"; then
  exit 1
fi