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

PAGES_URL="${PAGES_URL:-http://localhost:3000}"
PAGES_HOST="${PAGES_HOST:?PAGES_HOST is required}"
CONFIG="${RETENTION_CONFIG:-/etc/retention/retention.json}"
GITEA_API_URL="${GITEA_API_URL:-}"
GITEA_TOKEN="${GITEA_TOKEN:-}"

curl_with_host() {
  curl -sS -H "Host: ${PAGES_HOST}" "$@"
}

[ -f "$CONFIG" ] || { echo "ERROR: config missing: $CONFIG" >&2; exit 1; }

declare -A BRANCH_CACHE
branch_exists() {
  local owner="$1" repo="$2" branch="$3" key="${owner}/${repo}/${branch}"
  local status

  [ -z "$GITEA_API_URL" ] && return 0
  [ -z "$GITEA_TOKEN" ] && return 0

  if [ "${BRANCH_CACHE[$key]:-}" = "1" ]; then
    return 0
  fi

  status=$(curl -sS -o /dev/null -w "%{http_code}" \
    -H "Authorization: token ${GITEA_TOKEN}" \
    "${GITEA_API_URL}/api/v1/repos/${owner}/${repo}/branches/${branch}" 2>/dev/null || echo "000")

  if [ "$status" = "200" ]; then
    BRANCH_CACHE[$key]=1
    return 0
  fi
  return 1
}

default_max_age=$(jq -r '.branches.default.maxAgeDays // 90' "$CONFIG")
default_keep_min=$(jq -r '.branches.default.keepMin // 5' "$CONFIG")

rule_max_age() {
  local branch="$1" v
  v=$(jq -r --arg b "$branch" '.branches[$b].maxAgeDays // empty' "$CONFIG")
  [ -n "$v" ] && echo "$v" || echo "$default_max_age"
}

rule_keep_min() {
  local branch="$1" v
  v=$(jq -r --arg b "$branch" '.branches[$b].keepMin // empty' "$CONFIG")
  [ -n "$v" ] && echo "$v" || echo "$default_keep_min"
}

age_days() {
  local published="$1" epoch_pub now
  epoch_pub=$(date -u -d "$published" +%s 2>/dev/null || echo 0)
  [ "$epoch_pub" -eq 0 ] && echo 99999 && return
  now=$(date -u +%s)
  echo $(( (now - epoch_pub) / 86400 ))
}

parse_path() {
  local rel="$1"
  OWNER="${rel%%/*}"
  rest="${rel#*/}"
  REPO="${rest%%/*}"
}

echo "Fetching manifest from ${PAGES_URL}/.git-pages/manifest.json"
MANIFEST=$(curl_with_host "${PAGES_URL}/.git-pages/manifest.json")
echo "Manifest loaded"

META_PATHS=$(echo "$MANIFEST" | jq -r '.contents | to_entries[] | select(.key | test("/reports/")) | select(.key | endswith("/.meta")) | .key' 2>/dev/null || true)

if [ -z "$META_PATHS" ]; then
  echo "No .meta files found under /reports/ — nothing to clean"
  exit 0
fi

echo ""
echo "=== Phase 1: collect reports ==="
declare -A SEEN_REPORTS
declare -a REPORTS
while IFS= read -r meta_path; do
  report_dir=$(dirname "$meta_path")
  
  # Skip duplicates - same report dir already processed
  [ -z "${SEEN_REPORTS[$report_dir]:-}" ] || continue
  SEEN_REPORTS[$report_dir]=1
  
  parse_path "$report_dir"
  meta_content=$(curl_with_host "${PAGES_URL}/${meta_path}" 2>/dev/null || true)
  [ -n "$meta_content" ] || { echo "  WARN: could not fetch $meta_path"; continue; }

  branch=$(echo "$meta_content" | jq -r '.branch // empty' 2>/dev/null || true)
  published=$(echo "$meta_content" | jq -r '.published_at // empty' 2>/dev/null || true)

  [ -n "$branch" ] || { echo "  WARN: no branch in $meta_path"; continue; }
  [ -n "$published" ] || { echo "  WARN: no published_at in $meta_path"; continue; }

  days=$(age_days "$published")
  REPORTS+=("${report_dir}|${OWNER}|${REPO}|${branch}|${days}")
  echo "  ${OWNER}/${REPO} branch=${branch} age=${days}d"
done <<< "$META_PATHS"

[ "${#REPORTS[@]}" -eq 0 ] && { echo "No actionable reports"; exit 0; }

echo ""
echo "=== Phase 2: check branches in Gitea ==="
declare -a TO_DELETE
declare -a KEEP
for entry in "${REPORTS[@]}"; do
  IFS='|' read -r dir owner repo branch days <<< "$entry"

  if [ -n "$GITEA_API_URL" ] && [ -n "$GITEA_TOKEN" ]; then
    if branch_exists "$owner" "$repo" "$branch"; then
      echo "  BRANCH EXISTS: ${owner}/${repo}/${branch}"
      KEEP+=("${dir}|${owner}|${repo}|${branch}|${days}")
    else
      echo "  BRANCH DELETED: ${owner}/${repo}/${branch} -> DELETE"
      TO_DELETE+=("$dir")
    fi
  else
    KEEP+=("${dir}|${owner}|${repo}|${branch}|${days}")
  fi
done

echo ""
echo "=== Phase 3: apply retention rules to remaining reports ==="
declare -A BRANCH_COUNTS
if [ "${#KEEP[@]}" -gt 0 ]; then
  IFS=$'\n'
  for entry in $(printf '%s\n' "${KEEP[@]}" | sort -t'|' -k4,4 -k5,5rn); do
    IFS='|' read -r dir owner repo branch days <<< "$entry"
    max_age=$(rule_max_age "$branch")
    keep_min=$(rule_keep_min "$branch")

    if [ "$days" -gt "$max_age" ]; then
      echo "  DELETE: ${dir} (age ${days}d > maxAge ${max_age}d, branch ${branch})"
      TO_DELETE+=("$dir")
      continue
    fi

    key="${branch}"
    count="${BRANCH_COUNTS[$key]:-0}"
    count=$((count + 1))
    BRANCH_COUNTS["$key"]=$count
    if [ "$count" -gt "$keep_min" ]; then
      echo "  DELETE: ${dir} (kept ${keep_min}/${count}, exceeds keepMin, branch ${branch})"
      TO_DELETE+=("$dir")
    fi
  done
  unset IFS
fi

if [ "${#TO_DELETE[@]}" -eq 0 ]; then
  echo "Nothing to delete"
  exit 0
fi

echo ""
echo "=== Phase 4: whiteout deletion ==="
echo "Creating whiteout tar for ${#TO_DELETE[@]} report(s)..."

WHITEOUT_TAR=$(mktemp)
trap 'rm -f "$WHITEOUT_TAR"' EXIT

python3 -c "
import tarfile, sys

tar = tarfile.open(name='${WHITEOUT_TAR}', mode='w')

dirs = set()
for d in sys.argv[1:]:
    dirs.add(d.strip())

tarinfo = tarfile.TarInfo()
tarinfo.type = tarfile.CHRTYPE
tarinfo.devmajor = 0
tarinfo.devminor = 0

for d in sorted(dirs, key=len, reverse=True):
    info = tarinfo
    info.name = d
    tar.addfile(info)

tar.close()
" "${TO_DELETE[@]}"

echo "Patching ${PAGES_URL}/ with whiteout tar..."
HTTP_CODE=$(curl_with_host -X PATCH "${PAGES_URL}/" \
  -H "Content-Type: application/x-tar" \
  -H "Atomic: no" \
  --data-binary @"${WHITEOUT_TAR}" \
  -w "%{http_code}" \
  -o /dev/null)

echo "HTTP $HTTP_CODE"
if [ "$HTTP_CODE" = "200" ] || [ "$HTTP_CODE" = "204" ]; then
  echo "Retention cleanup finished."
else
  echo "ERROR: retention HTTP ${HTTP_CODE}" >&2
  exit 1
fi