#!/bin/bash
# Laboratori Cloud - Lab Preparation Script
# Part of: "Corso Soluzioni Cloud"
#
# Description: Cleans only resources created by this course to avoid port/network conflicts before starting a lab.
# Usage: ./scripts/prepare-lab.sh [--dry-run] [--keep-volumes]

set -u

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

DRY_RUN=false
KEEP_VOLUMES=false

print_error() {
    echo -e "${RED}[ERROR]${NC} $1" >&2
}

print_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

print_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

print_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

print_usage() {
    cat << EOF
Usage: $0 [--dry-run] [--keep-volumes]

Prepares the environment for a new lab by removing only resources created by this course.

Options:
  --dry-run       Show what would be removed without changing anything
  --keep-volumes  Remove containers and networks, but preserve named volumes
  -h, --help      Show this help message

What this script targets:
  - Containers named lab01*, lab02-*, lab03-*, lab04-*, lab05-*
  - Networks named lab-01-iam_default, lab-03-compute_default, lab-04-storage_default, lab02-vpc-*, lab05-vpc-*
  - Volumes named lab-02-network_*, lab-03-compute_*, lab-04-storage_*, lab-05-database_*

Examples:
  $0
  $0 --dry-run
  $0 --keep-volumes

Exit codes:
  0 - Preparation completed successfully
  1 - Invalid arguments or command failure
EOF
}

while [ $# -gt 0 ]; do
    case "$1" in
        --dry-run)
            DRY_RUN=true
            ;;
        --keep-volumes)
            KEEP_VOLUMES=true
            ;;
        -h|--help)
            print_usage
            exit 0
            ;;
        *)
            print_error "Unknown option: $1"
            echo ""
            print_usage
            exit 1
            ;;
    esac
    shift
done

mapfile -t COURSE_CONTAINERS < <(docker ps -a --format '{{.ID}} {{.Names}}' 2>/dev/null | grep -E '^[0-9a-f]+ (lab01|lab02-|lab03-|lab04-|lab05-)' | cut -d' ' -f1)
mapfile -t COURSE_NETWORKS < <(docker network ls --format '{{.Name}}' 2>/dev/null | grep -E '^(lab02-vpc-|lab05-vpc-|lab-01-iam_default|lab-03-compute_default|lab-04-storage_default)' || true)
mapfile -t COURSE_VOLUMES < <(docker volume ls --format '{{.Name}}' 2>/dev/null | grep -E '^lab-(02-network|03-compute|04-storage|05-database)_' || true)

echo "=========================================="
echo "Laboratori Cloud - Prepare Lab"
echo "=========================================="
echo ""

if [ "$DRY_RUN" = true ]; then
    print_warn "DRY RUN MODE: no changes will be made"
fi

if [ "$KEEP_VOLUMES" = true ]; then
    print_warn "KEEP VOLUMES MODE: named volumes will be preserved"
fi

echo ""
print_info "Resources detected for this course:"
echo "  - Containers: ${#COURSE_CONTAINERS[@]}"
echo "  - Networks:   ${#COURSE_NETWORKS[@]}"
echo "  - Volumes:    ${#COURSE_VOLUMES[@]}"
echo ""

if [ ${#COURSE_CONTAINERS[@]} -eq 0 ] && [ ${#COURSE_NETWORKS[@]} -eq 0 ] && { [ "$KEEP_VOLUMES" = true ] || [ ${#COURSE_VOLUMES[@]} -eq 0 ]; }; then
    print_success "No course resources found. Environment already ready."
    exit 0
fi

run_or_print() {
    local description="$1"
    shift

    if [ "$DRY_RUN" = true ]; then
        print_info "Would ${description}: $*"
    else
        "$@"
    fi
}

if [ ${#COURSE_CONTAINERS[@]} -gt 0 ]; then
    print_info "Removing course containers..."
    if [ "$DRY_RUN" = true ]; then
        run_or_print "remove containers" docker rm -f "${COURSE_CONTAINERS[@]}"
    else
        docker rm -f "${COURSE_CONTAINERS[@]}" >/dev/null 2>&1 || true
    fi
    print_success "Processed ${#COURSE_CONTAINERS[@]} container(s)"
fi

if [ ${#COURSE_NETWORKS[@]} -gt 0 ]; then
    print_info "Removing course networks..."
    if [ "$DRY_RUN" = true ]; then
        run_or_print "remove networks" docker network rm "${COURSE_NETWORKS[@]}"
    else
        docker network rm "${COURSE_NETWORKS[@]}" >/dev/null 2>&1 || true
    fi
    print_success "Processed ${#COURSE_NETWORKS[@]} network(s)"
fi

if [ "$KEEP_VOLUMES" = false ] && [ ${#COURSE_VOLUMES[@]} -gt 0 ]; then
    print_info "Removing course volumes..."
    if [ "$DRY_RUN" = true ]; then
        run_or_print "remove volumes" docker volume rm "${COURSE_VOLUMES[@]}"
    else
        docker volume rm "${COURSE_VOLUMES[@]}" >/dev/null 2>&1 || true
    fi
    print_success "Processed ${#COURSE_VOLUMES[@]} volume(s)"
elif [ "$KEEP_VOLUMES" = true ]; then
    print_info "Skipping volume removal as requested"
fi

echo ""
if [ "$DRY_RUN" = true ]; then
    print_success "Dry run completed"
else
    print_success "Environment ready for the next lab"
fi

exit 0