#!/bin/bash
set -euo pipefail

# Phase 6, Plan 02, Task 1: Automated Backup Script
# Supports both Docker and Standalone deployment modes
# Usage: ./backup.sh [daily|weekly|manual] [retention_days]

BACKUP_TYPE="${1:-manual}"
RETENTION_DAYS="${2:-30}"
BACKUP_DIR="./backups"
DATA_DIR="./data"
TIMESTAMP=$(date +%Y-%m-%d_%H-%M-%S)
BACKUP_FILE="$BACKUP_DIR/inventory-$TIMESTAMP.tar.gz"

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

log_info() { echo -e "${GREEN}[INFO]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; exit 1; }

# Create backup directory
mkdir -p "$BACKUP_DIR"

# Determine deployment mode
if command -v docker-compose &> /dev/null; then
  log_info "Docker deployment mode detected"
  IS_DOCKER=true

  # Verify Docker daemon is running
  docker ps > /dev/null 2>&1 || log_error "Docker daemon not running"

  # 1. Verify services are running
  log_info "Checking services..."
  if ! docker-compose ps | grep -q "Up"; then
    log_warn "Not all services running; attempting to start..."
    docker-compose up -d
  fi

  # 2. Stop backend to ensure DB consistency
  log_info "Stopping backend service (DB consistency)..."
  docker-compose stop backend
else
  log_info "Standalone deployment mode detected"
  IS_DOCKER=false

  # For standalone mode, we'll just backup while running
  # (Process is single-threaded, so minimal locking risk)
  log_warn "Standalone mode: backing up with minimal service pause"
fi

# Wait for graceful shutdown (Docker only)
[[ "$IS_DOCKER" == "true" ]] && sleep 2

# 3. Create backup tarball
log_info "Creating backup: $BACKUP_FILE"

tar --exclude="$DATA_DIR/caddy_*" \
    --exclude="$BACKUP_DIR" \
    --exclude=".git" \
    --exclude="node_modules" \
    --exclude=".next" \
    --exclude=".venv" \
    --exclude="__pycache__" \
    -czf "$BACKUP_FILE" \
    "$DATA_DIR/inventory.db" \
    "$DATA_DIR/inventory.db-wal" \
    "$DATA_DIR/inventory.db-shm" \
    "config/" \
    "inventory.env" \
    2>/dev/null || log_error "Backup creation failed"

# Restart backend (Docker only)
if [[ "$IS_DOCKER" == "true" ]]; then
  log_info "Restarting backend service..."
  docker-compose start backend

  # Wait for backend to be ready
  sleep 5

  # Verify backend is healthy
  if curl -sf "http://localhost:8000/health" > /dev/null; then
    log_info "Backend restored and healthy"
  else
    log_warn "Backend not responding yet; check logs with 'docker-compose logs -f backend'"
  fi
fi

# 4. Verify backup integrity
log_info "Verifying backup integrity..."
if tar -tzf "$BACKUP_FILE" > /dev/null 2>&1; then
  log_info "✓ Backup verified"
else
  log_error "Backup corrupted"
fi

# 5. Log backup metadata
BACKUP_SIZE=$(du -h "$BACKUP_FILE" | cut -f1)
BACKUP_VERSION=$(cat VERSION.json 2>/dev/null | grep version | cut -d'"' -f4 || echo "unknown")
log_info "Backup size: $BACKUP_SIZE, Version: $BACKUP_VERSION"

# 6. Cleanup old backups
log_info "Cleaning up backups older than $RETENTION_DAYS days..."
find "$BACKUP_DIR" -name "inventory-*.tar.gz" -type f -mtime +$RETENTION_DAYS -delete

# 7. Create backup manifest
cat > "$BACKUP_DIR/MANIFEST.txt" << EOF
Backup Metadata
===============
Timestamp: $TIMESTAMP
Type: $BACKUP_TYPE
Retention: $RETENTION_DAYS days
Size: $BACKUP_SIZE
Version: $BACKUP_VERSION
Deployment Mode: $([ "$IS_DOCKER" == "true" ] && echo "Docker" || echo "Standalone")
Contents: DB, config, certificates (excluding certs)
Restored: Not yet

Command to restore:
./restore.sh $BACKUP_FILE
EOF

log_info "Backup complete: $BACKUP_FILE"
log_info "Retention policy: Delete after $RETENTION_DAYS days"
log_info "Next backup: $(date -d '+1 day' '+%Y-%m-%d')"