#!/usr/bin/env bash
# =============================================================================
# skills/ingest/scripts/run-prune.sh
# Symmetric companion to run-ingest: prune source pages whose raw source no
# longer exists. RE-DERIVES the orphan set itself (mirrors orphan-wiki.sh) — it
# never trusts a list handed in by n8n, so there is no "detected-vs-pruned"
# race. Removes ONLY the pages it derived plus their index entries, commits
# ONLY wiki/ on chore/prune-orphans-<date>, and opens a GATED removal PR (the
# operator approves the deletion; principle 2). Never deletes of its own accord.
#
# Runs OUTSIDE the model, on vm101, cwd = genome checkout. The wrapper (`pi
# prune`) has already taken the per-genome lock and done clean_start, exactly
# like `pi ingest` — so this script does neither.
#
#   run-prune.sh <genome>
#
# Emits a single JSON result line on stdout for n8n to parse.
# =============================================================================
set -euo pipefail

genome="${1:?usage: run-prune.sh <genome>}"
SCRIPTS="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

fail() {
  jq -nc --arg stage "$1" --arg reason "$2" '{status:"error", stage:$stage, reason:$reason}'
  exit 1
}

command -v jq      >/dev/null 2>&1 || { echo '{"status":"error","reason":"jq missing"}'; exit 1; }
command -v python3 >/dev/null 2>&1 || fail "deps" "python3 missing (needed by index-append.py)"

# --- re-derive orphans (same rule as orphan-wiki.sh; computed fresh, here, now) ---
# A wiki/sources/*.md page is orphaned when its frontmatter source_path points at
# a raw file that no longer exists. Legacy pages without source_path are ignored.
declare -a ORPH=()
for page in wiki/sources/*.md; do
  [[ -e "$page" ]] || continue
  sp="$(sed -n 's/^source_path:[[:space:]]*//p' "$page" | tr -d '\r' | head -n1)"
  [[ -n "$sp" ]] || continue
  [[ -f "$sp" ]] || ORPH+=("$page")
done

if [[ ${#ORPH[@]} -eq 0 ]]; then
  jq -nc '{status:"ok", count:0, pruned:[], detail:"no orphans"}'
  exit 0
fi

# --- remove each orphan page + its index entry (anti-traversal, wiki/-only) ---
declare -a PRUNED=()
for page in "${ORPH[@]}"; do
  case "$page" in
    wiki/*) : ;;
    *) fail "prune" "refusing to remove outside wiki/: ${page}" ;;
  esac
  case "$page" in *..*) fail "prune" "path traversal in page: ${page}" ;; esac
  [[ -f "$page" ]] || continue
  rm -f "$page"
  link="${page#wiki/}"; link="${link%.md}"            # e.g. sources/foo
  python3 "${SCRIPTS}/index-append.py" --remove "$link" \
    || fail "index" "index-append --remove failed for ${link}"
  PRUNED+=("$link")
done

# --- assemble the PR body ---
date_tag="$(date +%F)"
body="$(mktemp)"
trap 'rm -f "$body"' EXIT
{
  echo "## Prune orphaned sources"
  echo ""
  echo "These source pages reference a \`source_path\` whose raw file no longer exists"
  echo "in \`raw/\`. Removing them keeps the wiki in sync with git (the source of truth)."
  echo ""
  echo "| Removed page |"
  echo "|--------------|"
  for l in "${PRUNED[@]}"; do echo "| \`wiki/${l}.md\` |"; done
} > "$body"

# --- open the GATED removal PR on a chore/ branch (open-pr --branch override) ---
branch="chore/prune-orphans-${date_tag}"
pr_out="$( bash "${SCRIPTS}/open-pr.sh" \
  --branch "$branch" \
  --title "chore: prune ${#PRUNED[@]} orphaned source(s)" \
  --body-file "$body" --base "${INGEST_BASE:-main}" 2>&1 )" && pr_rc=0 || pr_rc=$?
pr_url="$(printf '%s\n' "$pr_out" | sed -n 's/^PR opened: //p' | head -n1)"

# --- result line for n8n ---
jq -nc \
  --arg status "$([[ $pr_rc -eq 0 ]] && echo ok || echo pr_failed)" \
  --argjson count "${#PRUNED[@]}" \
  --arg pr_url "$pr_url" \
  --arg detail "$pr_out" \
  --argjson pruned "$(printf '%s\n' "${PRUNED[@]}" | jq -R . | jq -s .)" \
  '{status:$status, count:$count, pr_url:$pr_url, pruned:$pruned, detail:$detail}'

[[ $pr_rc -eq 0 ]] || exit 1