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

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
UPDATER="${SCRIPT_DIR}/update.sh"

ENABLED="false"
MANIFEST="${SCRIPT_DIR}/manifest.production.json"
SOURCE_POLICY=""
BIN_ROOT="/opt/selective-vpn/bin"
TARGET=""
COMPONENTS_RAW=""
ROLLOUT_STAGE="stable"
COHORT_ID=""
FORCE_ROLLOUT=0
SIGNATURE_MODE=""
MIN_INTERVAL_SEC=21600
JITTER_SEC=0
FORCE_NOW=0
DRY_RUN=0
STATE_DIR=""
LOCK_FILE=""

usage() {
  cat <<'EOF'
Usage:
  auto_update.sh [--enabled true|false] [--manifest PATH] [--source-policy PATH]
                 [--bin-root DIR] [--target OS-ARCH] [--component NAME[,NAME...]]
                 [--rollout-stage stable|canary|any] [--cohort-id 0..99]
                 [--signature-mode off|optional|required]
                 [--min-interval-sec N] [--jitter-sec N]
                 [--state-dir DIR] [--lock-file PATH]
                 [--force-rollout] [--force-now] [--dry-run]

Description:
  Opt-in scheduler wrapper around update.sh.
  Default behavior is disabled; when enabled, it enforces interval gating and lock.

Examples:
  ./scripts/transport-packaging/auto_update.sh --enabled true
  ./scripts/transport-packaging/auto_update.sh --enabled true --component singbox,phoenix --min-interval-sec 3600
EOF
}

require_cmd() {
  local cmd="$1"
  if ! command -v "$cmd" >/dev/null 2>&1; then
    echo "[transport-auto-update] missing required command: ${cmd}" >&2
    exit 1
  fi
}

bool_normalize() {
  local raw
  raw="$(echo "$1" | tr '[:upper:]' '[:lower:]' | xargs)"
  case "$raw" in
    1|true|yes|on) echo "true" ;;
    0|false|no|off|"") echo "false" ;;
    *)
      echo "[transport-auto-update] invalid boolean value: ${1}" >&2
      exit 1
      ;;
  esac
}

int_validate_non_negative() {
  local name="$1"
  local value="$2"
  if [[ ! "$value" =~ ^[0-9]+$ ]]; then
    echo "[transport-auto-update] ${name} must be a non-negative integer" >&2
    exit 1
  fi
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --enabled)
      ENABLED="${2:-}"
      shift 2
      ;;
    --manifest)
      MANIFEST="${2:-}"
      shift 2
      ;;
    --source-policy)
      SOURCE_POLICY="${2:-}"
      shift 2
      ;;
    --bin-root)
      BIN_ROOT="${2:-}"
      shift 2
      ;;
    --target)
      TARGET="${2:-}"
      shift 2
      ;;
    --component)
      COMPONENTS_RAW="${2:-}"
      shift 2
      ;;
    --rollout-stage)
      ROLLOUT_STAGE="${2:-}"
      shift 2
      ;;
    --cohort-id)
      COHORT_ID="${2:-}"
      shift 2
      ;;
    --signature-mode)
      SIGNATURE_MODE="${2:-}"
      shift 2
      ;;
    --min-interval-sec)
      MIN_INTERVAL_SEC="${2:-}"
      shift 2
      ;;
    --jitter-sec)
      JITTER_SEC="${2:-}"
      shift 2
      ;;
    --state-dir)
      STATE_DIR="${2:-}"
      shift 2
      ;;
    --lock-file)
      LOCK_FILE="${2:-}"
      shift 2
      ;;
    --force-rollout)
      FORCE_ROLLOUT=1
      shift
      ;;
    --force-now)
      FORCE_NOW=1
      shift
      ;;
    --dry-run)
      DRY_RUN=1
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "[transport-auto-update] unknown argument: $1" >&2
      usage >&2
      exit 1
      ;;
  esac
done

ENABLED="$(bool_normalize "$ENABLED")"
int_validate_non_negative "min-interval-sec" "$MIN_INTERVAL_SEC"
int_validate_non_negative "jitter-sec" "$JITTER_SEC"

if [[ "$ENABLED" != "true" ]]; then
  echo "[transport-auto-update] disabled (opt-in mode)"
  exit 0
fi

if [[ ! -x "$UPDATER" ]]; then
  echo "[transport-auto-update] updater not found or not executable: ${UPDATER}" >&2
  exit 1
fi
if [[ ! -f "$MANIFEST" ]]; then
  echo "[transport-auto-update] manifest not found: ${MANIFEST}" >&2
  exit 1
fi
if [[ -n "$SOURCE_POLICY" && ! -f "$SOURCE_POLICY" ]]; then
  echo "[transport-auto-update] source policy not found: ${SOURCE_POLICY}" >&2
  exit 1
fi

require_cmd flock
require_cmd date

if [[ -z "$STATE_DIR" ]]; then
  STATE_DIR="${BIN_ROOT}/.packaging/auto-update"
fi
mkdir -p "$STATE_DIR"
if [[ -z "$LOCK_FILE" ]]; then
  LOCK_FILE="${STATE_DIR}/auto-update.lock"
fi

last_run_file="${STATE_DIR}/last_run_epoch"
last_success_file="${STATE_DIR}/last_success_epoch"
last_error_file="${STATE_DIR}/last_error"

echo "[transport-auto-update] enabled=true"
echo "[transport-auto-update] manifest=${MANIFEST}"
echo "[transport-auto-update] state_dir=${STATE_DIR}"
echo "[transport-auto-update] min_interval_sec=${MIN_INTERVAL_SEC}"
if [[ -n "$COMPONENTS_RAW" ]]; then
  echo "[transport-auto-update] components=${COMPONENTS_RAW}"
fi

exec 9>"$LOCK_FILE"
if ! flock -n 9; then
  echo "[transport-auto-update] skip: another auto-update process is running"
  exit 0
fi

now_epoch="$(date +%s)"
last_run_epoch=0
if [[ -f "$last_run_file" ]]; then
  last_run_epoch="$(cat "$last_run_file" 2>/dev/null || echo 0)"
  [[ "$last_run_epoch" =~ ^[0-9]+$ ]] || last_run_epoch=0
fi

elapsed=$((now_epoch - last_run_epoch))
if [[ "$FORCE_NOW" -ne 1 && "$elapsed" -lt "$MIN_INTERVAL_SEC" ]]; then
  echo "[transport-auto-update] skip: interval gate (elapsed=${elapsed}s < ${MIN_INTERVAL_SEC}s)"
  exit 0
fi

if [[ "$JITTER_SEC" -gt 0 && "$FORCE_NOW" -ne 1 ]]; then
  jitter=$((RANDOM % (JITTER_SEC + 1)))
  if [[ "$jitter" -gt 0 ]]; then
    echo "[transport-auto-update] jitter sleep: ${jitter}s"
    sleep "$jitter"
  fi
fi

cmd=("$UPDATER" "--manifest" "$MANIFEST" "--bin-root" "$BIN_ROOT" "--rollout-stage" "$ROLLOUT_STAGE")
if [[ -n "$SOURCE_POLICY" ]]; then
  cmd+=("--source-policy" "$SOURCE_POLICY")
fi
if [[ -n "$TARGET" ]]; then
  cmd+=("--target" "$TARGET")
fi
if [[ -n "$COMPONENTS_RAW" ]]; then
  cmd+=("--component" "$COMPONENTS_RAW")
fi
if [[ -n "$COHORT_ID" ]]; then
  cmd+=("--cohort-id" "$COHORT_ID")
fi
if [[ -n "$SIGNATURE_MODE" ]]; then
  cmd+=("--signature-mode" "$SIGNATURE_MODE")
fi
if [[ "$FORCE_ROLLOUT" -eq 1 ]]; then
  cmd+=("--force-rollout")
fi
if [[ "$DRY_RUN" -eq 1 ]]; then
  cmd+=("--dry-run")
fi

echo "[transport-auto-update] run: ${cmd[*]}"
if "${cmd[@]}"; then
  date +%s >"$last_run_file"
  date +%s >"$last_success_file"
  : >"$last_error_file"
  echo "[transport-auto-update] success"
  exit 0
fi

rc=$?
date +%s >"$last_run_file"
{
  echo "ts=$(date -u +%Y-%m-%dT%H:%M:%SZ)"
  echo "exit_code=${rc}"
  echo "cmd=${cmd[*]}"
} >"$last_error_file"
echo "[transport-auto-update] failed rc=${rc}" >&2
exit "$rc"