#!/usr/bin/env bash
# gstack-update-check — periodic version check for all skills.
#
# Output (one line, or nothing):
#   JUST_UPGRADED <old> <new>       — marker found from recent upgrade
#   UPGRADE_AVAILABLE <old> <new>   — remote VERSION differs from local
#   (nothing)                       — up to date, snoozed, disabled, or check skipped
#
# Env overrides (for testing):
#   GSTACK_DIR          — override auto-detected gstack root
#   GSTACK_REMOTE_URL   — override remote VERSION URL
#   GSTACK_STATE_DIR    — override ~/.gstack state directory
set -euo pipefail

GSTACK_DIR="${GSTACK_DIR:-$(cd "$(dirname "$0")/.." && pwd)}"
STATE_DIR="${GSTACK_STATE_DIR:-$HOME/.gstack}"
CACHE_FILE="$STATE_DIR/last-update-check"
MARKER_FILE="$STATE_DIR/just-upgraded-from"
SNOOZE_FILE="$STATE_DIR/update-snoozed"
VERSION_FILE="$GSTACK_DIR/VERSION"
REMOTE_URL="${GSTACK_REMOTE_URL:-https://raw.githubusercontent.com/garrytan/gstack/main/VERSION}"

# ─── Step 0: Check if updates are disabled ────────────────────
_UC=$("$GSTACK_DIR/bin/gstack-config" get update_check 2>/dev/null || true)
if [ "$_UC" = "false" ]; then
  exit 0
fi

# ─── Snooze helper ──────────────────────────────────────────
# check_snooze <remote_version>
#   Returns 0 if snoozed (should stay quiet), 1 if not snoozed (should output).
#
#   Snooze file format: <version> <level> <epoch>
#   Level durations: 1=24h, 2=48h, 3+=7d
#   New version (version mismatch) resets snooze.
check_snooze() {
  local remote_ver="$1"
  if [ ! -f "$SNOOZE_FILE" ]; then
    return 1  # no snooze file → not snoozed
  fi
  local snoozed_ver snoozed_level snoozed_epoch
  snoozed_ver="$(awk '{print $1}' "$SNOOZE_FILE" 2>/dev/null || true)"
  snoozed_level="$(awk '{print $2}' "$SNOOZE_FILE" 2>/dev/null || true)"
  snoozed_epoch="$(awk '{print $3}' "$SNOOZE_FILE" 2>/dev/null || true)"

  # Validate: all three fields must be non-empty
  if [ -z "$snoozed_ver" ] || [ -z "$snoozed_level" ] || [ -z "$snoozed_epoch" ]; then
    return 1  # corrupt file → not snoozed
  fi

  # Validate: level and epoch must be integers
  case "$snoozed_level" in *[!0-9]*) return 1 ;; esac
  case "$snoozed_epoch" in *[!0-9]*) return 1 ;; esac

  # New version dropped? Ignore snooze.
  if [ "$snoozed_ver" != "$remote_ver" ]; then
    return 1
  fi

  # Compute snooze duration based on level
  local duration
  case "$snoozed_level" in
    1) duration=86400 ;;   # 24 hours
    2) duration=172800 ;;  # 48 hours
    *) duration=604800 ;;  # 7 days (level 3+)
  esac

  local now
  now="$(date +%s)"
  local expires=$(( snoozed_epoch + duration ))
  if [ "$now" -lt "$expires" ]; then
    return 0  # still snoozed
  fi

  return 1  # snooze expired
}

# ─── Step 1: Read local version ──────────────────────────────
LOCAL=""
if [ -f "$VERSION_FILE" ]; then
  LOCAL="$(cat "$VERSION_FILE" 2>/dev/null | tr -d '[:space:]')"
fi
if [ -z "$LOCAL" ]; then
  exit 0  # No VERSION file → skip check
fi

# ─── Step 2: Check "just upgraded" marker ─────────────────────
if [ -f "$MARKER_FILE" ]; then
  OLD="$(cat "$MARKER_FILE" 2>/dev/null | tr -d '[:space:]')"
  rm -f "$MARKER_FILE"
  rm -f "$SNOOZE_FILE"
  mkdir -p "$STATE_DIR"
  echo "UP_TO_DATE $LOCAL" > "$CACHE_FILE"
  if [ -n "$OLD" ]; then
    echo "JUST_UPGRADED $OLD $LOCAL"
  fi
  exit 0
fi

# ─── Step 3: Check cache freshness (12h = 720 min) ──────────
if [ -f "$CACHE_FILE" ]; then
  # Cache is fresh if modified within 720 minutes
  STALE=$(find "$CACHE_FILE" -mmin +720 2>/dev/null || true)
  if [ -z "$STALE" ]; then
    # Cache is fresh — read it
    CACHED="$(cat "$CACHE_FILE" 2>/dev/null || true)"
    case "$CACHED" in
      UP_TO_DATE*)
        # Verify local version still matches cached version
        CACHED_VER="$(echo "$CACHED" | awk '{print $2}')"
        if [ "$CACHED_VER" = "$LOCAL" ]; then
          exit 0
        fi
        # Local version changed — fall through to re-check
        ;;
      UPGRADE_AVAILABLE*)
        # Verify local version still matches cached old version
        CACHED_OLD="$(echo "$CACHED" | awk '{print $2}')"
        if [ "$CACHED_OLD" = "$LOCAL" ]; then
          CACHED_NEW="$(echo "$CACHED" | awk '{print $3}')"
          if check_snooze "$CACHED_NEW"; then
            exit 0  # snoozed — stay quiet
          fi
          echo "$CACHED"
          exit 0
        fi
        # Local version changed (manual upgrade?) — fall through to re-check
        ;;
    esac
  fi
fi

# ─── Step 4: Slow path — fetch remote version ────────────────
mkdir -p "$STATE_DIR"

REMOTE=""
REMOTE="$(curl -sf --max-time 5 "$REMOTE_URL" 2>/dev/null || true)"
REMOTE="$(echo "$REMOTE" | tr -d '[:space:]')"

# Validate: must look like a version number (reject HTML error pages)
if ! echo "$REMOTE" | grep -qE '^[0-9]+\.[0-9.]+$'; then
  # Invalid or empty response — assume up to date
  echo "UP_TO_DATE $LOCAL" > "$CACHE_FILE"
  exit 0
fi

if [ "$LOCAL" = "$REMOTE" ]; then
  echo "UP_TO_DATE $LOCAL" > "$CACHE_FILE"
  exit 0
fi

# Versions differ — upgrade available
echo "UPGRADE_AVAILABLE $LOCAL $REMOTE" > "$CACHE_FILE"
if check_snooze "$REMOTE"; then
  exit 0  # snoozed — stay quiet
fi
echo "UPGRADE_AVAILABLE $LOCAL $REMOTE"