#!/bin/bash

# Fail fast and show errors
set -euo pipefail

# --- User-editable parameters ---
REPO="${REPO:-rytbank/data-schedules}"
DAYS_OLD="${DAYS_OLD:-30}"
EXCLUDE_PATTERN="${EXCLUDE_PATTERN:-^(main|dev-env|uat-env)$}"
DEFAULT_BRANCH="${DEFAULT_BRANCH:-main}"
DRY_RUN="${DRY_RUN:-true}"
FORCE_DELETE="${FORCE_DELETE:-false}"

# --- Check for dependencies ---
if ! command -v gh >/dev/null 2>&1; then
  echo "'gh' CLI not found; please install from https://cli.github.com/"
  exit 1
fi

# --- Confirm authentication ---
if ! gh auth status >/dev/null 2>&1; then
  echo "GitHub CLI not authenticated; run 'gh auth login'."
  exit 1
fi

# --- Calculate cutoff date ---
if date -v-1d +%Y-%m-%dT%H:%M:%SZ >/dev/null 2>&1; then
  # macOS/BSD date
  CUTOFF_DATE=$(date -u -v-"$DAYS_OLD"d +%Y-%m-%dT%H:%M:%SZ)
else
  # GNU date (Linux)
  CUTOFF_DATE=$(date -u -d "$DAYS_OLD days ago" +%Y-%m-%dT%H:%M:%SZ)
fi

echo "Fetching branches for $REPO..."

branches=($(gh api "repos/$REPO/branches" --paginate --jq '.[].name'))

echo "Analyzing branches older than $CUTOFF_DATE..."

for branch in "${branches[@]}"; do
  if echo "$branch" | grep -Eq "$EXCLUDE_PATTERN"; then
    continue
  fi
  last_commit_date=$(gh api "repos/$REPO/commits/$branch" --jq '.commit.committer.date' 2>/dev/null || true)
  if [[ -n "$last_commit_date" && "$last_commit_date" < "$CUTOFF_DATE" ]]; then
    echo "Branch $branch is stale since $last_commit_date"
    if git branch --contains "origin/$branch" | grep -q "$DEFAULT_BRANCH"; then
      if [[ "$DRY_RUN" == "false" ]]; then
        echo "[DELETE] $branch"
        echo "$branch,$last_commit_date,DELETED" >> stale_branches.csv
        # gh api -X DELETE "repos/$REPO/git/refs/heads/$branch"
      else
        echo "[DRY RUN] Would delete: $branch"
        echo "$branch,$last_commit_date,DRY_DELETED" >> stale_branches.csv
      fi
    else
      if [[ "$FORCE_DELETE" == "true" ]]; then
        if [[ "$DRY_RUN" == "false" ]]; then
          echo "[FORCE DELETE] $branch"
          echo "$branch,$last_commit_date,FORCE_DELETED" >> stale_branches.csv
          # gh api -X DELETE "repos/$REPO/git/refs/heads/$branch"
        else
          echo "[DRY RUN] Would force delete: $branch"
          echo "$branch,$last_commit_date,DRY_FORCE_DELETED" >> stale_branches.csv
        fi
      else
        echo "[SKIP] $branch not merged into $DEFAULT_BRANCH"
        echo "$branch,$last_commit_date,SKIPPED" >> stale_branches.csv
      fi
    fi
  fi
done

echo "Done"