#!/bin/bash
# Backup Verification Script
# Verifies database backups are working correctly

set -e

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

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

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

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

# Configuration
BACKUP_DIR="${BACKUP_DIR:-/backups/postgres}"
RETENTION_DAYS="${RETENTION_DAYS:-7}"
DB_NAME="${DB_NAME:-sankofa}"

# Check if kubectl is available
if ! command -v kubectl &> /dev/null; then
    log_error "kubectl not found. This script requires kubectl access."
    exit 1
fi

# Verify backup directory exists
verify_backup_directory() {
    log_info "Verifying backup directory..."
    
    if [ -d "$BACKUP_DIR" ]; then
        test_pass "Backup directory exists"
    else
        test_fail "Backup directory does not exist: $BACKUP_DIR"
        return 1
    fi
}

# Check recent backups
check_recent_backups() {
    log_info "Checking for recent backups..."
    
    local recent_backups=$(find "$BACKUP_DIR" -name "*.sql" -o -name "*.dump" -mtime -1 2>/dev/null | wc -l)
    
    if [ $recent_backups -gt 0 ]; then
        log_info "Found $recent_backups backup(s) from last 24 hours"
        test_pass "Recent backups exist"
    else
        test_fail "No backups found in last 24 hours"
        return 1
    fi
}

# Verify backup integrity
verify_backup_integrity() {
    log_info "Verifying backup integrity..."
    
    local latest_backup=$(find "$BACKUP_DIR" -name "*.sql" -o -name "*.dump" -type f -printf '%T@ %p\n' | sort -n | tail -1 | cut -d' ' -f2-)
    
    if [ -z "$latest_backup" ]; then
        test_fail "No backup file found"
        return 1
    fi
    
    log_info "Testing backup: $latest_backup"
    
    # Check if file is not empty
    if [ -s "$latest_backup" ]; then
        test_pass "Backup file is not empty"
    else
        test_fail "Backup file is empty"
        return 1
    fi
    
    # Check if file is readable
    if [ -r "$latest_backup" ]; then
        test_pass "Backup file is readable"
    else
        test_fail "Backup file is not readable"
        return 1
    fi
    
    # For SQL dumps, check for basic SQL structure
    if [[ "$latest_backup" == *.sql ]]; then
        if grep -q "CREATE TABLE\|INSERT INTO" "$latest_backup" 2>/dev/null; then
            test_pass "Backup file contains SQL data"
        else
            log_warn "Backup file may be incomplete (no SQL statements found)"
        fi
    fi
}

# Check backup retention
check_backup_retention() {
    log_info "Checking backup retention policy..."
    
    local old_backups=$(find "$BACKUP_DIR" -name "*.sql" -o -name "*.dump" -mtime +$RETENTION_DAYS 2>/dev/null | wc -l)
    
    if [ $old_backups -gt 0 ]; then
        log_warn "Found $old_backups backup(s) older than $RETENTION_DAYS days"
        log_warn "Consider cleaning up old backups"
    else
        test_pass "Backup retention policy is being followed"
    fi
}

# Test backup restoration (dry run)
test_backup_restore() {
    log_info "Testing backup restoration (dry run)..."
    
    local latest_backup=$(find "$BACKUP_DIR" -name "*.sql" -o -name "*.dump" -type f -printf '%T@ %p\n' | sort -n | tail -1 | cut -d' ' -f2-)
    
    if [ -z "$latest_backup" ]; then
        test_fail "No backup file found for restore test"
        return 1
    fi
    
    # For SQL dumps, check if we can parse the file
    if [[ "$latest_backup" == *.sql ]]; then
        if head -100 "$latest_backup" | grep -q "PostgreSQL\|pg_dump" 2>/dev/null; then
            test_pass "Backup file appears to be a valid PostgreSQL dump"
        else
            log_warn "Backup file format may be unexpected"
        fi
    fi
}

# Check automated backup schedule
check_backup_schedule() {
    log_info "Checking backup automation..."
    
    # Check for cron jobs or Kubernetes CronJobs
    if kubectl get cronjob -n api postgres-backup &> /dev/null; then
        local schedule=$(kubectl get cronjob -n api postgres-backup -o jsonpath='{.spec.schedule}')
        log_info "Found backup CronJob with schedule: $schedule"
        test_pass "Backup automation configured"
    else
        log_warn "No backup CronJob found. Backups may not be automated."
        log_warn "Consider creating a CronJob for automated backups."
    fi
}

# Verify database connectivity
verify_db_connectivity() {
    log_info "Verifying database connectivity..."
    
    if kubectl exec -n api deployment/api -- \
        psql "${DATABASE_URL}" -c "SELECT 1" > /dev/null 2>&1; then
        test_pass "Database is accessible"
    else
        test_fail "Cannot connect to database"
        return 1
    fi
}

# Main execution
main() {
    echo "=========================================="
    echo "Sankofa Phoenix Backup Verification"
    echo "=========================================="
    echo ""
    
    local passed=0
    local failed=0
    
    verify_backup_directory && ((passed++)) || ((failed++))
    check_recent_backups && ((passed++)) || ((failed++))
    verify_backup_integrity && ((passed++)) || ((failed++))
    check_backup_retention && ((passed++)) || ((failed++))
    test_backup_restore && ((passed++)) || ((failed++))
    check_backup_schedule && ((passed++)) || ((failed++))
    verify_db_connectivity && ((passed++)) || ((failed++))
    
    echo ""
    echo "=========================================="
    echo "Verification Summary"
    echo "=========================================="
    echo "Passed:  ${GREEN}${passed}${NC}"
    echo "Failed:  ${RED}${failed}${NC}"
    echo ""
    
    if [ $failed -eq 0 ]; then
        log_info "All backup verifications passed!"
        exit 0
    else
        log_error "Some verifications failed. Please review backup configuration."
        exit 1
    fi
}

main "$@"