#!/bin/bash
# kb-staleness-check.sh — Scan knowledge base files for staleness
# Usage: bash scripts/kb-staleness-check.sh [--days N] [--priority-only] [--verbose] [--json] [--output FILE]
#
# Default threshold: 90 days
# Priority order: prices > compliance > features > architecture

set -euo pipefail

PLUGIN_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
# Scan all skill reference directories
KB_ROOTS=(
  "$PLUGIN_ROOT/skills/ms-ai-advisor/references"
  "$PLUGIN_ROOT/skills/ms-ai-governance/references"
  "$PLUGIN_ROOT/skills/ms-ai-security/references"
  "$PLUGIN_ROOT/skills/ms-ai-engineering/references"
  "$PLUGIN_ROOT/skills/ms-ai-infrastructure/references"
)

# Defaults
THRESHOLD_DAYS=90
PRIORITY_ONLY=false
VERBOSE=false
JSON_OUTPUT=false
OUTPUT_FILE=""

# Parse arguments
while [[ $# -gt 0 ]]; do
  case "$1" in
    --days)
      THRESHOLD_DAYS="$2"
      shift 2
      ;;
    --priority-only)
      PRIORITY_ONLY=true
      shift
      ;;
    --verbose)
      VERBOSE=true
      shift
      ;;
    --json)
      JSON_OUTPUT=true
      shift
      ;;
    --output)
      OUTPUT_FILE="$2"
      shift 2
      ;;
    *)
      echo "Unknown option: $1"
      echo "Usage: bash scripts/kb-staleness-check.sh [--days N] [--priority-only] [--verbose] [--json] [--output FILE]"
      exit 1
      ;;
  esac
done

for kb_dir in "${KB_ROOTS[@]}"; do
  if [ ! -d "$kb_dir" ]; then
    echo "WARNING: Knowledge base directory not found: $kb_dir" >&2
  fi
done

NOW=$(date +%s)
TOTAL=0
FRESH=0
STALE=0
STALE_CRITICAL=0
STALE_HIGH=0
STALE_MEDIUM=0
STALE_LOW=0

# Collect stale files for sorted summary
declare -a STALE_ENTRIES=()

get_priority() {
  local filepath="$1"
  local lower_path
  lower_path=$(echo "$filepath" | tr '[:upper:]' '[:lower:]')

  # Critical (30 days): cost, pricing, pris
  if echo "$lower_path" | grep -qE '(cost|pricing|pris)'; then
    echo "Critical:30"
    return
  fi

  # High (60 days): compliance, security, governance
  if echo "$lower_path" | grep -qE '(responsible-ai|norwegian-public-sector-governance|ai-security-engineering)'; then
    echo "High:60"
    return
  fi

  # Medium (90 days): platforms, features, extensibility
  if echo "$lower_path" | grep -qE '(platforms|copilot-extensibility|azure-ai-services|multi-modal|performance-scalability|monitoring-observability|agent-orchestration|data-engineering|api-management|hybrid-edge|bcdr|rag-architecture|mlops-genaiops|prompt-engineering)'; then
    echo "Medium:90"
    return
  fi

  # Low (180 days): architecture, development, patterns
  echo "Low:180"
}

for KB_ROOT in "${KB_ROOTS[@]}"; do
  [ -d "$KB_ROOT" ] || continue
  while IFS= read -r -d '' file; do
    TOTAL=$((TOTAL + 1))

    # macOS-compatible stat for modification time
    MOD_EPOCH=$(stat -f '%m' "$file" 2>/dev/null || stat -c '%Y' "$file" 2>/dev/null)
    DAYS_OLD=$(( (NOW - MOD_EPOCH) / 86400 ))

    REL_PATH="${file#"$KB_ROOT/"}"
    PRIORITY_INFO=$(get_priority "$REL_PATH")
    PRIORITY="${PRIORITY_INFO%%:*}"
    PRIORITY_THRESHOLD="${PRIORITY_INFO##*:}"

    if [ "$DAYS_OLD" -gt "$PRIORITY_THRESHOLD" ]; then
      STALE=$((STALE + 1))
      case "$PRIORITY" in
        Critical) STALE_CRITICAL=$((STALE_CRITICAL + 1)) ;;
        High)     STALE_HIGH=$((STALE_HIGH + 1)) ;;
        Medium)   STALE_MEDIUM=$((STALE_MEDIUM + 1)) ;;
        Low)      STALE_LOW=$((STALE_LOW + 1)) ;;
      esac

      FULL_REL="${file#"$PLUGIN_ROOT/"}"
      if [ "$JSON_OUTPUT" = true ]; then
        echo "[STALE] $REL_PATH — ${DAYS_OLD} days old (threshold: ${PRIORITY_THRESHOLD}) — Priority: $PRIORITY" >&2
      else
        echo "[STALE] $REL_PATH — ${DAYS_OLD} days old (threshold: ${PRIORITY_THRESHOLD}) — Priority: $PRIORITY"
      fi
      STALE_ENTRIES+=("${DAYS_OLD}:${PRIORITY}:${FULL_REL}")
    else
      FRESH=$((FRESH + 1))
      if [ "$VERBOSE" = true ] && [ "$PRIORITY_ONLY" = false ]; then
        if [ "$JSON_OUTPUT" = true ]; then
          echo "[FRESH] $REL_PATH — ${DAYS_OLD} days old (threshold: ${PRIORITY_THRESHOLD}) — Priority: $PRIORITY" >&2
        else
          echo "[FRESH] $REL_PATH — ${DAYS_OLD} days old (threshold: ${PRIORITY_THRESHOLD}) — Priority: $PRIORITY"
        fi
      fi
    fi
  done < <(find "$KB_ROOT" -name '*.md' -type f -print0)
done

# JSON output mode
if [ "$JSON_OUTPUT" = true ]; then
  JSON="{"
  JSON+="\"generated_at\":\"$(date -Iseconds)\","
  JSON+="\"total\":$TOTAL,"
  JSON+="\"fresh\":$FRESH,"
  JSON+="\"stale\":$STALE,"
  JSON+="\"stale_by_priority\":{\"critical\":$STALE_CRITICAL,\"high\":$STALE_HIGH,\"medium\":$STALE_MEDIUM,\"low\":$STALE_LOW},"
  JSON+="\"files\":["

  FIRST=true
  for entry in "${STALE_ENTRIES[@]}"; do
    days="${entry%%:*}"
    rest="${entry#*:}"
    priority="${rest%%:*}"
    filepath="${rest#*:}"

    # Determine skill from path
    skill="unknown"
    case "$filepath" in
      *ms-ai-advisor*) skill="ms-ai-advisor" ;;
      *ms-ai-engineering*) skill="ms-ai-engineering" ;;
      *ms-ai-governance*) skill="ms-ai-governance" ;;
      *ms-ai-security*) skill="ms-ai-security" ;;
      *ms-ai-infrastructure*) skill="ms-ai-infrastructure" ;;
    esac

    # Determine category from path
    category=$(echo "$filepath" | sed -E 's|.*/references/([^/]+)/.*|\1|')

    if [ "$FIRST" = true ]; then
      FIRST=false
    else
      JSON+=","
    fi
    JSON+="{\"path\":\"$filepath\",\"skill\":\"$skill\",\"category\":\"$category\",\"age_days\":$days,\"priority\":\"$priority\"}"
  done

  JSON+="]}"

  if [ -n "$OUTPUT_FILE" ]; then
    echo "$JSON" > "$OUTPUT_FILE"
    echo "JSON written to: $OUTPUT_FILE" >&2
  else
    echo "$JSON"
  fi
  exit 0
fi

echo ""
echo "=== KB Freshness Report ==="
echo "Total files: $TOTAL"
echo "Fresh: $FRESH"
echo "Stale: $STALE (Critical: $STALE_CRITICAL, High: $STALE_HIGH, Medium: $STALE_MEDIUM, Low: $STALE_LOW)"

if [ "$STALE" -gt 0 ]; then
  echo ""
  echo "Recommended update order:"

  # Sort stale entries: Critical first, then High, Medium, Low; within priority by age descending
  PRIORITY_ORDER="Critical High Medium Low"
  INDEX=1

  for prio in $PRIORITY_ORDER; do
    # Collect entries for this priority, sort by age descending
    PRIO_ENTRIES=()
    for entry in "${STALE_ENTRIES[@]}"; do
      entry_prio="${entry#*:}"
      entry_prio="${entry_prio%%:*}"
      if [ "$entry_prio" = "$prio" ]; then
        PRIO_ENTRIES+=("$entry")
      fi
    done

    # Sort by days (first field) descending
    if [ ${#PRIO_ENTRIES[@]} -gt 0 ]; then
      SORTED=$(printf '%s\n' "${PRIO_ENTRIES[@]}" | sort -t: -k1 -nr)
      while IFS= read -r sorted_entry; do
        days="${sorted_entry%%:*}"
        rest="${sorted_entry#*:}"
        rest="${rest#*:}"
        echo "  ${INDEX}. [$prio] $rest (${days} days)"
        INDEX=$((INDEX + 1))
      done <<< "$SORTED"
    fi
  done
fi

echo ""
echo "Run with --verbose to see fresh files. Use --days N to override threshold. Use --json for machine-readable output."