#!/bin/sh
# ============================================================
# Memento Note — Docker Entrypoint
# Automatic DB migration with backup, retry, and cleanup.
# Safe for production: no data loss on image updates.
# ============================================================

set -e

BACKUP_DIR="/app/data/backups"
MAX_BACKUPS=5
DB_WAIT_RETRIES=30
DB_WAIT_INTERVAL=2
MIGRATE_TIMEOUT=120

# --- Logging ---
log()  { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [entrypoint] $*"; }
warn() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [entrypoint] WARNING: $*" >&2; }
err()  { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [entrypoint] ERROR: $*" >&2; }

# --- Detect database type ---
DB_TYPE="unknown"
case "$DATABASE_URL" in
  postgres://*|postgresql://*) DB_TYPE="postgres" ;;
  file:*)                       DB_TYPE="sqlite" ;;
esac
log "Database type: $DB_TYPE"

# --- Wait for database to be reachable ---
wait_for_db() {
  if [ "$DB_TYPE" = "sqlite" ]; then
    log "SQLite — no connection check needed."
    return 0
  fi

  log "Waiting for database connection..."
  i=0
  while [ "$i" -lt "$DB_WAIT_RETRIES" ]; do
    if node -e "
      const m = process.env.DATABASE_URL.match(/@([^:\/]+):(\d+)/);
      if (!m) process.exit(1);
      const net = require('net');
      const s = net.createConnection(parseInt(m[2]), m[1], () => { s.end(); process.exit(0); });
      s.setTimeout(3000, () => { s.destroy(); process.exit(1); });
      s.on('error', () => process.exit(1));
    " 2>/dev/null; then
      log "Database is reachable."
      return 0
    fi
    i=$((i + 1))
    log "  Attempt $i/$DB_WAIT_RETRIES — retrying in ${DB_WAIT_INTERVAL}s..."
    sleep "$DB_WAIT_INTERVAL"
  done

  err "Database unreachable after $((DB_WAIT_RETRIES * DB_WAIT_INTERVAL)) seconds. Aborting."
  exit 1
}

# --- Create backup before migration ---
create_backup() {
  mkdir -p "$BACKUP_DIR"
  ts=$(date '+%Y%m%d_%H%M%S')

  case "$DB_TYPE" in
    postgres)
      backup_file="$BACKUP_DIR/pre_migrate_${ts}.sql.gz"
      log "Creating PostgreSQL backup: $backup_file"
      if command -v pg_dump >/dev/null 2>&1; then
        if pg_dump --no-owner --no-privileges --format=plain "$DATABASE_URL" 2>/dev/null | gzip > "$backup_file" 2>/dev/null; then
          size=$(du -h "$backup_file" | cut -f1)
          log "Backup created successfully ($size)"
        else
          warn "pg_dump failed. Continuing without backup."
          rm -f "$backup_file"
        fi
      else
        warn "pg_dump not available. Skipping PostgreSQL backup."
        warn "Install postgresql-client in the Docker image for automatic backups."
      fi
      ;;
    sqlite)
      db_path="${DATABASE_URL#file:}"
      # Handle relative paths
      case "$db_path" in
        /*) ;;
        *)  db_path="/app/$db_path" ;;
      esac
      backup_file="$BACKUP_DIR/pre_migrate_${ts}.sqlite"
      if [ -f "$db_path" ]; then
        log "Creating SQLite backup: $backup_file"
        cp "$db_path" "$backup_file"
        size=$(du -h "$backup_file" | cut -f1)
        log "Backup created successfully ($size)"
      else
        warn "SQLite file not found at $db_path — skipping backup (first run)."
      fi
      ;;
    *)
      warn "Unknown database type '$DB_TYPE'. Skipping backup."
      ;;
  esac
}

# --- Clean up old backups (keep last N) ---
cleanup_old_backups() {
  count=$(ls -1 "$BACKUP_DIR"/pre_migrate_* 2>/dev/null | wc -l)
  if [ "$count" -gt "$MAX_BACKUPS" ]; then
    to_remove=$((count - MAX_BACKUPS))
    log "Cleaning up $to_remove old backup(s), keeping last $MAX_BACKUPS..."
    ls -1t "$BACKUP_DIR"/pre_migrate_* 2>/dev/null | tail -n "$to_remove" | xargs rm -f
  fi
}

# --- Run Prisma migrations ---
run_migrations() {
  log "Running Prisma migrations..."
  if timeout "$MIGRATE_TIMEOUT" node ./node_modules/prisma/build/index.js migrate deploy 2>&1; then
    log "Migrations applied successfully."
    return 0
  else
    exit_code=$?
    err "Migration failed (exit code $exit_code)."
    return "$exit_code"
  fi
}

# ============================================================
# Main flow
# ============================================================

# Step 1: Wait for database
wait_for_db

# Step 2: Backup
create_backup

# Step 3: Cleanup old backups
cleanup_old_backups

# Step 4: Migrate
if ! run_migrations; then
  err "Migration failed — server will NOT start to prevent data corruption."
  err "A backup was saved in $BACKUP_DIR (if backup was successful)."
  err "To restore: gunzip the .sql.gz file, then: psql DATABASE_URL < backup.sql"
  exit 1
fi

# Background scheduler: call /api/cron/agents every 5 minutes
(
  sleep 60
  while true; do
    node -e "
      const http = require('http');
      const req = http.request('http://localhost:3000/api/cron/agents', { method: 'POST' }, (res) => {
        let body = '';
        res.on('data', (d) => body += d);
        res.on('end', () => console.log('[Scheduler] Cron response:', res.statusCode, body));
      });
      req.on('error', (e) => console.error('[Scheduler] Cron error:', e.message));
      req.end();
    " 2>&1 || true
    sleep 300
  done
) &

# Step 5: Start server
log "Starting server..."
exec node server.js