#!/bin/bash
# ==============================================================================
# Wordly.art - Disaster Recovery (DR) Backup & Restore Playbook
# ==============================================================================
# Packages configuration files (.env, docker-compose) and database backups
# into a single archive, and automates restorations on new machines.
#
# Usage:
#   ./disaster-recovery.sh --backup           # Package and backup configs + DB to NAS
#   ./disaster-recovery.sh --restore FILE.tar.gz # Extract configs, boot Docker, restore DB
# ==============================================================================

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
TIMESTAMP=$(date +"%Y%m%d_%H%M%S")

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

log() { echo -e "[DR ${TIMESTAMP}] $1"; }
log_success() { echo -e "[DR ${TIMESTAMP}] ${GREEN}$1${NC}"; }
log_warning() { echo -e "[DR ${TIMESTAMP}] ${YELLOW}WARNING: $1${NC}"; }
log_error() { echo -e "[DR ${TIMESTAMP}] ${RED}ERROR: $1${NC}"; }

# Sourcing .env for path defaults
ENV_FILE="${PROJECT_ROOT}/.env"
if [ -f "${ENV_FILE}" ]; then
    set -a
    source "${ENV_FILE}"
    set +a
fi

# Configuration defaults
NAS_BACKUP_DIR="${NAS_BACKUP_DIR:-/mnt/nas-backups/wordly}"
DR_BACKUP_DIR="${NAS_BACKUP_DIR}/dr"
DR_RETENTION_DAYS=14

# ==============================================================================
# BACKUP ACTION
# ==============================================================================
perform_backup() {
    log "Initiating complete Disaster Recovery backup..."

    # 1. Trigger DB Backup first
    log "Triggering database backup..."
    if ! bash "${SCRIPT_DIR}/backup-database.sh" --full; then
        log_error "Database backup failed. Aborting DR package."
        exit 1
    fi

    # 2. Locate the latest DB backup
    # Check default backup directory (resolved from .env or script fallback)
    local local_backup_dir
    local_backup_dir="${BACKUP_DIR:-${PROJECT_ROOT}/backups}"
    local latest_db_backup
    
    latest_db_backup=$(ls -t "${local_backup_dir}/daily/"*.gz 2>/dev/null | head -n 1 || true)
    
    if [ -z "${latest_db_backup}" ]; then
        log_error "Could not locate the generated database backup file in ${local_backup_dir}/daily/."
        exit 1
    fi
    log "Latest database backup located: $(basename "${latest_db_backup}")"

    # 3. Create temp packing folder
    local packing_dir="${PROJECT_ROOT}/temp_dr_pack_${TIMESTAMP}"
    mkdir -p "${packing_dir}"
    
    # 4. Copy configurations
    log "Packaging configuration files..."
    if [ -f "${PROJECT_ROOT}/.env" ]; then
        cp "${PROJECT_ROOT}/.env" "${packing_dir}/.env.production"
    else
        log_warning "No .env file found at project root. Continuing without it."
    fi

    # Copy docker-compose files
    for f in docker-compose.yml docker-compose.local.yml docker-compose.monitoring.yml docker-compose.dev.yml; do
        if [ -f "${PROJECT_ROOT}/${f}" ]; then
            cp "${PROJECT_ROOT}/${f}" "${packing_dir}/"
        fi
    done

    # Copy docker directory (Prometheus, Grafana, Nginx configs, Dockerfiles)
    if [ -d "${PROJECT_ROOT}/docker" ]; then
        cp -r "${PROJECT_ROOT}/docker" "${packing_dir}/"
    fi

    # Copy scripts directory (so restore scripts are present in the package)
    if [ -d "${PROJECT_ROOT}/scripts" ]; then
        cp -r "${PROJECT_ROOT}/scripts" "${packing_dir}/"
    fi

    # Copy the DB backup archive
    mkdir -p "${packing_dir}/db_backup"
    cp "${latest_db_backup}" "${packing_dir}/db_backup/"

    # 5. Compress Everything
    mkdir -p "${DR_BACKUP_DIR}"
    local dr_archive_name="wordly_dr_${TIMESTAMP}.tar.gz"
    local dr_archive_path="${DR_BACKUP_DIR}/${dr_archive_name}"

    log "Compressing configurations and database into DR package..."
    tar -czf "${dr_archive_path}" -C "${packing_dir}" .

    # Clean up temp packaging folder
    rm -rf "${packing_dir}"

    if [ -f "${dr_archive_path}" ] && [ -s "${dr_archive_path}" ]; then
        local size
        size=$(du -h "${dr_archive_path}" | cut -f1)
        log_success "Disaster Recovery backup package created: ${dr_archive_name} (${size})"
        log_success "Stored securely at: ${dr_archive_path}"
        
        # 6. Apply retention cleanups
        log "Cleaning up old DR packages (retention: ${DR_RETENTION_DAYS} days)..."
        find "${DR_BACKUP_DIR}" -name "wordly_dr_*.tar.gz" -mtime +"${DR_RETENTION_DAYS}" -exec rm -f {} \;
        log_success "Disaster Recovery backup complete."
    else
        log_error "DR Archive compression failed."
        exit 1
    fi
}

# ==============================================================================
# RESTORE ACTION
# ==============================================================================
perform_restore() {
    local dr_package="$1"

    if [ -z "${dr_package}" ]; then
        log_error "No DR package archive specified."
        echo "Usage: $0 --restore <path_to_archive.tar.gz>"
        echo "Available archives in ${DR_BACKUP_DIR}:"
        ls -lh "${DR_BACKUP_DIR}"/wordly_dr_*.tar.gz 2>/dev/null || echo "  (none)"
        exit 1
    fi

    if [ ! -f "${dr_package}" ]; then
        log_error "Archive file not found: ${dr_package}"
        exit 1
    fi

    echo ""
    log_warning "RESTORE DISASTER RECOVERY PACKAGE - THIS WILL OVERWRITE ENVIRONMENT CONFIGURATIONS AND DATABASES!"
    echo "  Archive: ${dr_package}"
    echo "  Target : Current Server Host (Workspace)"
    echo ""
    read -p "Type 'RESTORE-ALL' to confirm complete system restore: " confirm_val
    if [ "${confirm_val}" != "RESTORE-ALL" ]; then
        log "System restore cancelled."
        exit 0
    fi

    log "Extracting DR archive contents..."
    
    # Create safety backup of existing .env before overwrite
    if [ -f "${PROJECT_ROOT}/.env" ]; then
        cp "${PROJECT_ROOT}/.env" "${PROJECT_ROOT}/.env.bak_before_dr_restore_${TIMESTAMP}"
        log "Created backup of existing .env: .env.bak_before_dr_restore_${TIMESTAMP}"
    fi

    # Extract configs directly into project root
    tar -xzf "${dr_package}" -C "${PROJECT_ROOT}"

    # Restore .env from packaged .env.production
    if [ -f "${PROJECT_ROOT}/.env.production" ]; then
        mv "${PROJECT_ROOT}/.env.production" "${PROJECT_ROOT}/.env"
        log "Restored .env configuration"
    fi

    # Reload variables from restored .env
    set -a
    source "${PROJECT_ROOT}/.env"
    set +a

    log_success "Docker and configurations extracted successfully."

    # Boot Docker Compose Services
    log "Spinning up Docker containers (database, redis, backend, frontend)..."
    if ! command -v docker-compose &>/dev/null && ! docker compose version &>/dev/null; then
        log_error "docker-compose is not installed. Please install Docker first."
        exit 1
    fi

    # Try running docker compose
    local compose_cmd="docker compose"
    if ! docker compose version &>/dev/null; then
        compose_cmd="docker-compose"
    fi

    # Start services in detached mode
    ${compose_cmd} up -d

    # Locate the embedded database backup
    local db_backup_archive
    db_backup_archive=$(ls "${PROJECT_ROOT}/db_backup/"*.gz 2>/dev/null | head -n 1 || true)

    if [ -z "${db_backup_archive}" ]; then
        log_error "Database backup archive not found inside the DR package extraction."
        exit 1
    fi

    log "Database backup located: $(basename "${db_backup_archive}")"

    # Wait for database container to be healthy (PostgreSQL)
    local db_type="sqlite"
    if [[ "${DATABASE_URL:-}" =~ ^postgres ]]; then
        db_type="postgres"
    fi

    if [ "${db_type}" = "postgres" ]; then
        local postgres_container="${POSTGRES_CONTAINER:-wordly-postgres}"
        log "Waiting for PostgreSQL container (${postgres_container}) to be healthy..."
        for i in $(seq 1 30); do
            if docker inspect --format='{{.State.Health.Status}}' "${postgres_container}" 2>/dev/null | grep -q "healthy"; then
                log_success "Database container is healthy."
                break
            fi
            echo "  Waiting for database... ($i/30)"
            sleep 2
        done
    else
        sleep 2
    fi

    # Restore the database using the database backup script
    log "Triggering database restore..."
    # Make sure backups/daily folder exists and copy the db backup there for backup-database.sh to see it
    local local_backup_dir="${BACKUP_DIR:-${PROJECT_ROOT}/backups}"
    mkdir -p "${local_backup_dir}/daily"
    cp "${db_backup_archive}" "${local_backup_dir}/daily/"

    local db_archive_filename
    db_archive_filename=$(basename "${db_backup_archive}")

    # Run DB restore
    # Sourcing backup-database.sh with the file name
    # We pass the confirmation non-interactively using YES or mock prompt if needed,
    # but backup-database.sh reads YES/RESTORE. Let's make it easy:
    log "Restoring DB contents... (You will need to type 'RESTORE' if prompted)"
    bash "${SCRIPT_DIR}/backup-database.sh" --restore "${db_archive_filename}"

    # Clean up extracted folders
    rm -rf "${PROJECT_ROOT}/db_backup"
    
    # Restart app to clear connection caches
    log "Restarting application backend..."
    ${compose_cmd} restart backend

    log_success "=========================================================================="
    log_success "DISASTER RECOVERY SYSTEM RESTORE COMPLETE!"
    log_success "=========================================================================="
    log "Your application has been restored and started."
    log "Next Steps:"
    log "1. Verify the service is online: curl http://localhost:8000/health"
    log "2. Update your Nginx Proxy Manager (NPM) domains to point to this server's IP."
    echo ""
}

# ==============================================================================
# MAIN ENTRY
# ==============================================================================
main() {
    case "${1:-}" in
        --backup)
            perform_backup
            ;;
        --restore)
            perform_restore "${2:-}"
            ;;
        *)
            echo "Wordly Disaster Recovery Utility"
            echo "Usage:"
            echo "  $0 --backup                 # Package and copy configs + database to NAS"
            echo "  $0 --restore <archive.tar.gz> # Extract and restore full stack on new machine"
            exit 1
            ;;
    esac
}

main "$@"