#!/bin/bash
# Backup and Restore Testing Script
# Validates backup and restore procedures across the infrastructure

set -euo pipefail

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Function to print colored output
print_status() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

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

print_header() {
    echo -e "${BLUE}[HEADER]${NC} $1"
}

# Configuration
BACKUP_ROOT="/backup"
TEST_BACKUP_DIR="$BACKUP_ROOT/test_backup_$(date +%Y%m%d_%H%M%S)"
TEST_RESTORE_DIR="/tmp/test_restore_$(date +%Y%m%d_%H%M%S)"
HOSTS=("omv800.local" "jonathan-2518f5u" "surface" "fedora" "audrey")
OUTPUT_FILE="${1:-/tmp/backup_restore_test_report.txt}"
TEST_DATA_SIZE="100M"
COMPRESSION_TYPES=("gzip" "bzip2" "xz")
ENCRYPTION_KEY="test_encryption_key_$(date +%s)"

# Function to check backup infrastructure
check_backup_infrastructure() {
    print_header "Checking Backup Infrastructure"
    
    # Check if backup directory exists
    if [ ! -d "$BACKUP_ROOT" ]; then
        print_error "Backup directory $BACKUP_ROOT does not exist"
        print_status "Creating backup directory structure..."
        sudo mkdir -p "$BACKUP_ROOT"/{snapshots,database_dumps,configs,volumes,test}
        sudo chown -R $USER:$USER "$BACKUP_ROOT"
    fi
    
    # Check backup directory permissions
    if [ ! -w "$BACKUP_ROOT" ]; then
        print_error "Backup directory $BACKUP_ROOT is not writable"
        return 1
    fi
    
    # Check available space
    local available_space=$(df "$BACKUP_ROOT" | awk 'NR==2 {print $4}')
    local required_space=1048576  # 1GB in KB
    
    if [ "$available_space" -lt "$required_space" ]; then
        print_warning "Low disk space in backup directory: ${available_space}KB available, ${required_space}KB required"
    else
        print_status "Sufficient disk space available: ${available_space}KB"
    fi
    
    print_status "Backup infrastructure check completed"
}

# Function to create test data
create_test_data() {
    print_header "Creating Test Data"
    
    mkdir -p "$TEST_BACKUP_DIR"
    
    # Create various types of test data
    print_status "Creating database dump simulation..."
    dd if=/dev/urandom of="$TEST_BACKUP_DIR/database_dump.sql" bs=1M count=50 2>/dev/null
    
    print_status "Creating configuration files..."
    mkdir -p "$TEST_BACKUP_DIR/configs"
    for i in {1..10}; do
        echo "config_value_$i=test_data_$i" > "$TEST_BACKUP_DIR/configs/config_$i.conf"
    done
    
    print_status "Creating volume data simulation..."
    mkdir -p "$TEST_BACKUP_DIR/volumes"
    dd if=/dev/urandom of="$TEST_BACKUP_DIR/volumes/app_data.bin" bs=1M count=25 2>/dev/null
    
    print_status "Creating log files..."
    mkdir -p "$TEST_BACKUP_DIR/logs"
    for i in {1..5}; do
        echo "Log entry $i: $(date)" > "$TEST_BACKUP_DIR/logs/app_$i.log"
    done
    
    # Create metadata
    echo "Backup created: $(date)" > "$TEST_BACKUP_DIR/backup_metadata.txt"
    echo "Test data size: $(du -sh "$TEST_BACKUP_DIR" | cut -f1)" >> "$TEST_BACKUP_DIR/backup_metadata.txt"
    
    print_status "Test data created in $TEST_BACKUP_DIR"
}

# Function to test compression
test_compression() {
    print_header "Testing Compression Methods"
    
    local test_file="$TEST_BACKUP_DIR/compression_test.dat"
    dd if=/dev/urandom of="$test_file" bs=1M count=10 2>/dev/null
    
    for compression in "${COMPRESSION_TYPES[@]}"; do
        print_status "Testing $compression compression..."
        
        local start_time=$(date +%s.%N)
        local compressed_file="$test_file.$compression"
        
        case $compression in
            "gzip")
                gzip -c "$test_file" > "$compressed_file"
                ;;
            "bzip2")
                bzip2 -c "$test_file" > "$compressed_file"
                ;;
            "xz")
                xz -c "$test_file" > "$compressed_file"
                ;;
        esac
        
        local end_time=$(date +%s.%N)
        local duration=$(echo "$end_time - $start_time" | bc -l)
        local original_size=$(stat -c%s "$test_file")
        local compressed_size=$(stat -c%s "$compressed_file")
        local compression_ratio=$(echo "scale=2; $compressed_size * 100 / $original_size" | bc -l)
        
        echo "$compression: ${compression_ratio}% of original size, ${duration}s" >> "$OUTPUT_FILE"
        print_status "$compression: ${compression_ratio}% of original size, ${duration}s"
        
        # Test decompression
        local decompress_start=$(date +%s.%N)
        case $compression in
            "gzip")
                gunzip -c "$compressed_file" > "$test_file.decompressed"
                ;;
            "bzip2")
                bunzip2 -c "$compressed_file" > "$test_file.decompressed"
                ;;
            "xz")
                unxz -c "$compressed_file" > "$test_file.decompressed"
                ;;
        esac
        local decompress_end=$(date +%s.%N)
        local decompress_time=$(echo "$decompress_end - $decompress_start" | bc -l)
        
        # Verify integrity
        if cmp -s "$test_file" "$test_file.decompressed"; then
            echo "$compression decompression: PASSED (${decompress_time}s)" >> "$OUTPUT_FILE"
            print_status "$compression decompression: PASSED (${decompress_time}s)"
        else
            echo "$compression decompression: FAILED" >> "$OUTPUT_FILE"
            print_error "$compression decompression: FAILED"
        fi
        
        # Cleanup
        rm -f "$compressed_file" "$test_file.decompressed"
    done
    
    rm -f "$test_file"
}

# Function to test encryption
test_encryption() {
    print_header "Testing Encryption"
    
    local test_file="$TEST_BACKUP_DIR/encryption_test.dat"
    local encrypted_file="$test_file.encrypted"
    local decrypted_file="$test_file.decrypted"
    
    dd if=/dev/urandom of="$test_file" bs=1M count=5 2>/dev/null
    
    print_status "Testing AES-256 encryption..."
    
    local start_time=$(date +%s.%N)
    
    # Encrypt
    openssl enc -aes-256-cbc -salt -in "$test_file" -out "$encrypted_file" -pass pass:"$ENCRYPTION_KEY" 2>/dev/null
    
    local encrypt_end=$(date +%s.%N)
    local encrypt_time=$(echo "$encrypt_end - $start_time" | bc -l)
    
    # Decrypt
    local decrypt_start=$(date +%s.%N)
    openssl enc -aes-256-cbc -d -in "$encrypted_file" -out "$decrypted_file" -pass pass:"$ENCRYPTION_KEY" 2>/dev/null
    local decrypt_end=$(date +%s.%N)
    local decrypt_time=$(echo "$decrypt_end - $decrypt_start" | bc -l)
    
    # Verify integrity
    if cmp -s "$test_file" "$decrypted_file"; then
        echo "Encryption: PASSED (encrypt: ${encrypt_time}s, decrypt: ${decrypt_time}s)" >> "$OUTPUT_FILE"
        print_status "Encryption: PASSED (encrypt: ${encrypt_time}s, decrypt: ${decrypt_time}s)"
    else
        echo "Encryption: FAILED" >> "$OUTPUT_FILE"
        print_error "Encryption: FAILED"
    fi
    
    # Cleanup
    rm -f "$test_file" "$encrypted_file" "$decrypted_file"
}

# Function to test incremental backup
test_incremental_backup() {
    print_header "Testing Incremental Backup"
    
    local base_dir="$TEST_BACKUP_DIR/incremental"
    mkdir -p "$base_dir"
    
    # Create initial data
    echo "Initial data" > "$base_dir/file1.txt"
    echo "Initial data" > "$base_dir/file2.txt"
    
    # Create initial backup
    local backup1="$TEST_BACKUP_DIR/backup1.tar.gz"
    tar -czf "$backup1" -C "$base_dir" .
    
    # Modify data
    echo "Modified data" > "$base_dir/file1.txt"
    echo "New file" > "$base_dir/file3.txt"
    rm -f "$base_dir/file2.txt"
    
    # Create incremental backup
    local backup2="$TEST_BACKUP_DIR/backup2.tar.gz"
    tar -czf "$backup2" -C "$base_dir" .
    
    # Compare sizes
    local size1=$(stat -c%s "$backup1")
    local size2=$(stat -c%s "$backup2")
    
    echo "Incremental backup: Initial ${size1} bytes, Incremental ${size2} bytes" >> "$OUTPUT_FILE"
    print_status "Incremental backup: Initial ${size1} bytes, Incremental ${size2} bytes"
    
    # Test restore
    mkdir -p "$TEST_RESTORE_DIR/incremental"
    tar -xzf "$backup2" -C "$TEST_RESTORE_DIR/incremental"
    
    if [ -f "$TEST_RESTORE_DIR/incremental/file1.txt" ] && \
       [ -f "$TEST_RESTORE_DIR/incremental/file3.txt" ] && \
       [ ! -f "$TEST_RESTORE_DIR/incremental/file2.txt" ]; then
        echo "Incremental restore: PASSED" >> "$OUTPUT_FILE"
        print_status "Incremental restore: PASSED"
    else
        echo "Incremental restore: FAILED" >> "$OUTPUT_FILE"
        print_error "Incremental restore: FAILED"
    fi
    
    # Cleanup
    rm -f "$backup1" "$backup2"
}

# Function to test database backup simulation
test_database_backup() {
    print_header "Testing Database Backup Simulation"
    
    local db_dump="$TEST_BACKUP_DIR/database_backup.sql"
    
    # Create simulated database dump
    cat > "$db_dump" << 'EOF'
-- Simulated database dump
CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(50),
    email VARCHAR(100),
    created_at TIMESTAMP
);

INSERT INTO users VALUES (1, 'testuser', 'test@example.com', NOW());
INSERT INTO users VALUES (2, 'admin', 'admin@example.com', NOW());

-- Simulated configuration
SET GLOBAL max_connections = 100;
SET GLOBAL innodb_buffer_pool_size = '1G';
EOF
    
    # Test backup integrity
    if grep -q "CREATE TABLE" "$db_dump" && grep -q "INSERT INTO" "$db_dump"; then
        echo "Database backup simulation: PASSED" >> "$OUTPUT_FILE"
        print_status "Database backup simulation: PASSED"
    else
        echo "Database backup simulation: FAILED" >> "$OUTPUT_FILE"
        print_error "Database backup simulation: FAILED"
    fi
    
    # Test compression of database dump
    local compressed_dump="$db_dump.gz"
    gzip -c "$db_dump" > "$compressed_dump"
    
    local original_size=$(stat -c%s "$db_dump")
    local compressed_size=$(stat -c%s "$compressed_dump")
    local compression_ratio=$(echo "scale=2; $compressed_size * 100 / $original_size" | bc -l)
    
    echo "Database backup compression: ${compression_ratio}% of original size" >> "$OUTPUT_FILE"
    print_status "Database backup compression: ${compression_ratio}% of original size"
    
    # Cleanup
    rm -f "$compressed_dump"
}

# Function to test backup verification
test_backup_verification() {
    print_header "Testing Backup Verification"
    
    # Create test backup with checksums
    local test_files=("$TEST_BACKUP_DIR/file1.txt" "$TEST_BACKUP_DIR/file2.txt" "$TEST_BACKUP_DIR/file3.txt")
    
    for file in "${test_files[@]}"; do
        echo "Test data for $(basename "$file")" > "$file"
        sha256sum "$file" >> "$TEST_BACKUP_DIR/checksums.txt"
    done
    
    # Create backup archive
    local backup_archive="$TEST_BACKUP_DIR/verified_backup.tar.gz"
    tar -czf "$backup_archive" -C "$TEST_BACKUP_DIR" file1.txt file2.txt file3.txt checksums.txt
    
    # Test verification
    mkdir -p "$TEST_RESTORE_DIR/verification"
    tar -xzf "$backup_archive" -C "$TEST_RESTORE_DIR/verification"
    
    cd "$TEST_RESTORE_DIR/verification"
    if sha256sum -c checksums.txt >/dev/null 2>&1; then
        echo "Backup verification: PASSED" >> "$OUTPUT_FILE"
        print_status "Backup verification: PASSED"
    else
        echo "Backup verification: FAILED" >> "$OUTPUT_FILE"
        print_error "Backup verification: FAILED"
    fi
    
    cd - >/dev/null
}

# Function to test backup scheduling
test_backup_scheduling() {
    print_header "Testing Backup Scheduling"
    
    # Simulate backup scheduling
    local schedule_test="$TEST_BACKUP_DIR/schedule_test.txt"
    echo "Backup scheduled at: $(date)" > "$schedule_test"
    
    # Test cron-like scheduling
    local cron_entry="0 2 * * * /usr/local/bin/backup_script.sh"
    echo "Cron entry: $cron_entry" >> "$OUTPUT_FILE"
    print_status "Backup scheduling simulation completed"
    
    # Test backup rotation
    for i in {1..5}; do
        echo "Backup $i created at $(date)" > "$TEST_BACKUP_DIR/rotated_backup_$i.txt"
    done
    
    echo "Backup rotation: 5 test backups created" >> "$OUTPUT_FILE"
    print_status "Backup rotation: 5 test backups created"
}

# Function to generate test report
generate_report() {
    print_header "Generating Backup/Restore Test Report"
    
    echo "=== Backup and Restore Test Report ===" > "$OUTPUT_FILE"
    echo "Date: $(date)" >> "$OUTPUT_FILE"
    echo "Test Directory: $TEST_BACKUP_DIR" >> "$OUTPUT_FILE"
    echo "Restore Directory: $TEST_RESTORE_DIR" >> "$OUTPUT_FILE"
    echo "" >> "$OUTPUT_FILE"
    
    # Add system information
    echo "=== System Information ===" >> "$OUTPUT_FILE"
    echo "Hostname: $(hostname)" >> "$OUTPUT_FILE"
    echo "Kernel: $(uname -r)" >> "$OUTPUT_FILE"
    echo "Available disk space: $(df -h "$BACKUP_ROOT" | awk 'NR==2 {print $4}')" >> "$OUTPUT_FILE"
    echo "" >> "$OUTPUT_FILE"
    
    print_status "Test report initialized at $OUTPUT_FILE"
}

# Function to cleanup
cleanup() {
    print_header "Cleaning Up"
    
    # Remove test directories
    if [ -d "$TEST_BACKUP_DIR" ]; then
        rm -rf "$TEST_BACKUP_DIR"
        print_status "Removed test backup directory"
    fi
    
    if [ -d "$TEST_RESTORE_DIR" ]; then
        rm -rf "$TEST_RESTORE_DIR"
        print_status "Removed test restore directory"
    fi
}

# Function to display usage
usage() {
    echo "Usage: $0 [output_file]"
    echo "  output_file: Path to save test report (default: /tmp/backup_restore_test_report.txt)"
    echo ""
    echo "This script tests backup and restore procedures."
    echo "It validates compression, encryption, incremental backups, and verification."
}

# Main execution
main() {
    print_header "Starting Backup and Restore Testing"
    
    # Check dependencies
    for cmd in tar gzip bzip2 xz openssl sha256sum bc; do
        if ! command -v "$cmd" >/dev/null 2>&1; then
            print_error "Required command '$cmd' not found"
            exit 1
        fi
    done
    
    # Initialize report
    generate_report
    
    # Run tests
    if check_backup_infrastructure; then
        create_test_data
        test_compression
        test_encryption
        test_incremental_backup
        test_database_backup
        test_backup_verification
        test_backup_scheduling
        
        print_status "All backup/restore tests completed successfully"
        print_status "Report saved to: $OUTPUT_FILE"
    else
        print_error "Backup infrastructure check failed - cannot proceed with tests"
        exit 1
    fi
}

# Trap to ensure cleanup on exit
trap cleanup EXIT

# Parse command line arguments
if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
    usage
    exit 0
fi

# Run main function
main "$@"