#!/usr/bin/env bash
#
# add-host-runner.sh — Stand up an additional independent host-mode Gitea
# Actions runner as its own launchd service, for more CI parallelism.
#
# The canonical runner is the Homebrew-managed `act_runner` service
# (config: /opt/homebrew/etc/act_runner/config.yaml, capacity 2). Bumping a
# single runner's capacity high overloads the laptop and shares one workdir;
# registering *separate* runners gives clean isolation and scales linearly.
#
# Each extra runner gets:
#   - its own config dir   ~/Library/Application Support/act_runner-<N>/
#   - its own .runner file (separate Gitea registration)
#   - its own workdir      ~/.cache/act-<N>   (no cross-runner clashes)
#   - the SHARED secret     /opt/homebrew/etc/act_runner/runner.env (env_file)
#   - its own launchd plist ~/Library/LaunchAgents/com.bytelyst.act_runner-<N>.plist
#
# Usage:
#   bash add-host-runner.sh <N> [capacity]      # e.g. add-host-runner.sh 2 2
#   bash add-host-runner.sh 2 2 && bash add-host-runner.sh 3 2
#
# Requires: act_runner on PATH, a Gitea admin PAT at ~/.gitea_c5_pat,
# and the canonical runner.env to already exist (created during runner hardening).
#
# Idempotent: if runner <N> is already registered it reloads the service and exits.
set -euo pipefail

N="${1:?usage: add-host-runner.sh <N> [capacity]}"
CAP="${2:-2}"
INSTANCE="${GITEA_INSTANCE:-http://localhost:3300}"
PAT_FILE="${GITEA_PAT_FILE:-$HOME/.gitea_c5_pat}"
CANONICAL_CONFIG="${CANONICAL_CONFIG:-/opt/homebrew/etc/act_runner/config.yaml}"
SHARED_ENV_FILE="${SHARED_ENV_FILE:-/opt/homebrew/etc/act_runner/runner.env}"

BASE="$HOME/Library/Application Support/act_runner-$N"
CONFIG="$BASE/config.yaml"
RUNNER_FILE="$BASE/.runner"
WORKDIR="$HOME/.cache/act-$N"
PLIST="$HOME/Library/LaunchAgents/com.bytelyst.act_runner-$N.plist"
SVC_LABEL="com.bytelyst.act_runner-$N"
RUNNER_NAME="$(hostname -s)-$N"
LOG_DIR="$BASE/logs"

command -v act_runner >/dev/null 2>&1 || { echo "✗ act_runner not on PATH (brew install act_runner)" >&2; exit 1; }
[ -f "$PAT_FILE" ] || { echo "✗ no Gitea PAT at $PAT_FILE" >&2; exit 1; }
[ -f "$CANONICAL_CONFIG" ] || { echo "✗ canonical config not found: $CANONICAL_CONFIG" >&2; exit 1; }
PAT="$(cat "$PAT_FILE")"

mkdir -p "$BASE" "$WORKDIR" "$LOG_DIR"

echo "── add host runner #$N (capacity $CAP) ──"

# ── already registered? just (re)load the service ───────────────────────────
if [ -f "$RUNNER_FILE" ]; then
  echo "  ✓ runner #$N already registered ($RUNNER_FILE) — reloading service"
  launchctl bootout "gui/$(id -u)/$SVC_LABEL" 2>/dev/null || true
  launchctl bootstrap "gui/$(id -u)" "$PLIST" 2>/dev/null || launchctl load "$PLIST" 2>/dev/null || true
  launchctl list | grep "$SVC_LABEL" || echo "  (service not listed — check $LOG_DIR)"
  exit 0
fi

# ── derive a per-runner config from the canonical one ───────────────────────
# Preserve the proxy/env block + env_file; override file path, capacity, workdir.
python3 - "$CANONICAL_CONFIG" "$CONFIG" "$RUNNER_FILE" "$CAP" "$WORKDIR" "$SHARED_ENV_FILE" <<'PY'
import sys, yaml
src, dst, runner_file, cap, workdir, env_file = sys.argv[1:7]
cfg = yaml.safe_load(open(src)) or {}
cfg.setdefault("runner", {})
cfg["runner"]["file"] = runner_file
cfg["runner"]["capacity"] = int(cap)
cfg["runner"]["env_file"] = env_file
cfg.setdefault("host", {})
cfg["host"]["workdir_parent"] = workdir
yaml.safe_dump(cfg, open(dst, "w"), default_flow_style=False, sort_keys=False)
print(f"  + wrote {dst}")
PY

# ── fetch a one-time registration token (admin API) ─────────────────────────
REG_TOKEN=$(curl -fsS -H "Authorization: token $PAT" \
  "$INSTANCE/api/v1/admin/runners/registration-token" \
  | python3 -c "import json,sys; print(json.load(sys.stdin)['token'])")
[ -n "$REG_TOKEN" ] || { echo "✗ could not fetch registration token" >&2; exit 1; }

# ── register (host-mode labels) ─────────────────────────────────────────────
act_runner register \
  --no-interactive \
  --instance "$INSTANCE" \
  --token "$REG_TOKEN" \
  --name "$RUNNER_NAME" \
  --labels "ubuntu-latest:host,macos-latest:host,macos-15:host,self-hosted:host" \
  --config "$CONFIG"
echo "  ✓ registered as $RUNNER_NAME"

# ── write launchd plist ─────────────────────────────────────────────────────
RUNNER_BIN="$(command -v act_runner)"
cat > "$PLIST" <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key><string>$SVC_LABEL</string>
  <key>ProgramArguments</key>
  <array>
    <string>$RUNNER_BIN</string>
    <string>daemon</string>
    <string>--config</string>
    <string>$CONFIG</string>
  </array>
  <key>RunAtLoad</key><true/>
  <key>KeepAlive</key><true/>
  <key>WorkingDirectory</key><string>$BASE</string>
  <key>StandardOutPath</key><string>$LOG_DIR/act_runner.log</string>
  <key>StandardErrorPath</key><string>$LOG_DIR/act_runner.err</string>
</dict>
</plist>
EOF
echo "  + wrote $PLIST"

# ── load the service ────────────────────────────────────────────────────────
launchctl bootout "gui/$(id -u)/$SVC_LABEL" 2>/dev/null || true
launchctl bootstrap "gui/$(id -u)" "$PLIST" 2>/dev/null || launchctl load "$PLIST"
sleep 3
if launchctl list | grep -q "$SVC_LABEL"; then
  echo "  ✓ service loaded ($SVC_LABEL)"
else
  echo "  ⚠ service not listed — check $LOG_DIR/act_runner.err"
fi
echo "  log: $LOG_DIR/act_runner.log"