#!/bin/bash
# Quick Backup Verification - Verificare zilnică că backup-urile sunt OK
# Rulează acest script ZILNIC (automat via cron) pentru monitoring

BACKUP_DIR="/opt/oracle/backups/primary"
LOG_FILE="/opt/oracle/logs/dr/verify_$(date +%Y%m%d).log"

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

log() {
    local message="$1"
    local level="${2:-INFO}"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    case "$level" in
        "ERROR")   color="$RED" ;;
        "SUCCESS") color="$GREEN" ;;
        "WARNING") color="$YELLOW" ;;
        *)         color="$NC" ;;
    esac

    echo -e "${color}[$timestamp] [$level] $message${NC}" | tee -a "$LOG_FILE"
}

alert_email() {
    # TODO: Configure email alerts
    # echo "$1" | mail -s "Oracle DR Alert" admin@company.com
    log "ALERT: $1" "ERROR"
}

# ==================== CHECKS ====================

log "=== DR Backup Verification Started ===" "INFO"

# Check 1: Backup directory exists
if [ ! -d "$BACKUP_DIR" ]; then
    alert_email "Backup directory not found: $BACKUP_DIR"
    exit 1
fi
log "✅ Backup directory exists"

# Check 2: Backup files present
backup_count=$(find "$BACKUP_DIR" -name "*.BKP" -o -name "*.bkp" 2>/dev/null | wc -l)
if [ "$backup_count" -eq 0 ]; then
    alert_email "No backup files found in $BACKUP_DIR"
    exit 1
fi
log "✅ Found $backup_count backup file(s)"

# Check 3: Latest backup age
latest_backup=$(find "$BACKUP_DIR" -name "*.BKP" -o -name "*.bkp" 2>/dev/null | head -1)
if [ -z "$latest_backup" ]; then
    alert_email "No backup files found!"
    exit 1
fi

latest_backup_age=$(( ($(date +%s) - $(stat -c %Y "$latest_backup")) / 3600 ))
log "Latest backup: $(basename $latest_backup)"
log "Backup age: $latest_backup_age hours"

if [ $latest_backup_age -gt 30 ]; then
    alert_email "Latest backup is too old: $latest_backup_age hours (expected <30h)"
    log "❌ Backup TOO OLD!" "ERROR"
    exit 1
elif [ $latest_backup_age -gt 26 ]; then
    log "⚠️  Backup is getting old (>26h)" "WARNING"
else
    log "✅ Backup age is good (<26h)" "SUCCESS"
fi

# Check 4: Backup size reasonable
backup_size=$(du -sh "$BACKUP_DIR" 2>/dev/null | awk '{print $1}')
log "Total backup size: $backup_size"

# Check 5: Disk space available
free_space=$(df -h "$BACKUP_DIR" | tail -1 | awk '{print $4}')
free_space_gb=$(df -BG "$BACKUP_DIR" | tail -1 | awk '{print $4}' | sed 's/G//')

log "Free disk space: $free_space ($free_space_gb GB)"

if [ "$free_space_gb" -lt 10 ]; then
    alert_email "Low disk space on DR: only ${free_space_gb}GB free!"
    log "❌ DISK SPACE LOW!" "ERROR"
elif [ "$free_space_gb" -lt 20 ]; then
    log "⚠️  Disk space getting low (<20GB)" "WARNING"
else
    log "✅ Disk space OK (>20GB free)" "SUCCESS"
fi

# Check 6: File integrity (quick check - just read first and last block)
log "Running quick file integrity check..."
if head -c 1024 "$latest_backup" > /dev/null 2>&1 && tail -c 1024 "$latest_backup" > /dev/null 2>&1; then
    log "✅ Backup file is readable" "SUCCESS"
else
    alert_email "Backup file appears corrupted: $latest_backup"
    log "❌ BACKUP FILE CORRUPTED!" "ERROR"
    exit 1
fi

# Check 7: List all backup files with details
log ""
log "=== Backup Files Inventory ===" "INFO"
find "$BACKUP_DIR" -name "*.BKP" -o -name "*.bkp" 2>/dev/null | while read file; do
    size=$(du -h "$file" | awk '{print $1}')
    age=$(( ($(date +%s) - $(stat -c %Y "$file")) / 3600 ))
    log "  - $(basename $file): $size (${age}h old)"
done

# Summary
log ""
log "=== Verification Summary ===" "INFO"
log "✅ Backup directory: OK"
log "✅ Backup files: $backup_count present"
log "✅ Latest backup age: ${latest_backup_age}h (threshold: 30h)"
log "✅ Disk space: ${free_space_gb}GB free"
log "✅ File integrity: OK"
log ""
log "=== DR Backup Verification COMPLETED ===" "SUCCESS"

exit 0