#!/bin/bash

################################################################################
# Email Account/Domain Diagnostics
################################################################################
# Purpose: Verify email is working for specific address or domain
# Shows proof of delivery or identifies why emails aren't working
################################################################################

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
source "$SCRIPT_DIR/lib/common-functions.sh"
source "$SCRIPT_DIR/lib/system-detect.sh"
source "$SCRIPT_DIR/lib/email-functions.sh"

show_banner "Email Diagnostics - Verify Email Delivery"

# Get mail log path
MAIL_LOG=$(get_mail_log_path)
if [ ! -f "$MAIL_LOG" ]; then
    print_error "Mail log not found: $MAIL_LOG"
    exit 1
fi

print_success "Using mail log: $MAIL_LOG"
echo ""

# Ask what to check
echo -e "${BOLD}What would you like to check?${NC}"
echo ""
echo "  1) Specific email address (e.g., user@example.com)"
echo "  2) Entire domain (e.g., example.com)"
echo ""
read -p "Enter choice [1]: " check_type
check_type=${check_type:-1}

# Get email/domain to check
echo ""
if [ "$check_type" = "2" ]; then
    read -p "Enter domain to check (e.g., example.com): " target
    search_pattern="@${target}"
    check_label="domain $target"
else
    read -p "Enter email address to check: " target
    search_pattern="$target"
    check_label="email $target"
fi

if [ -z "$target" ]; then
    print_error "No email/domain provided"
    exit 1
fi

# Time period to check
echo ""
echo "Check logs from:"
echo "  1) Last 1 hour"
echo "  2) Last 6 hours"
echo "  3) Last 24 hours (recommended)"
echo "  4) Last 48 hours"
echo "  5) Last week"
echo ""
read -p "Enter choice [3]: " time_choice
time_choice=${time_choice:-3}

case "$time_choice" in
    1) hours=1 ;;
    2) hours=6 ;;
    3) hours=24 ;;
    4) hours=48 ;;
    5) hours=168 ;;
    *) hours=24 ;;
esac

echo ""
print_info "Analyzing $check_label for last $hours hours..."
echo ""

# Calculate time cutoff
if date --version 2>&1 | grep -q "GNU"; then
    # GNU date
    cutoff_time=$(date -d "$hours hours ago" +"%Y-%m-%d %H:%M:%S")
else
    # BSD date (macOS)
    cutoff_time=$(date -v-${hours}H +"%Y-%m-%d %H:%M:%S")
fi

################################################################################
# Analysis
################################################################################

TEMP_MATCHES="/tmp/email_diag_$$.txt"
grep -i "$search_pattern" "$MAIL_LOG" > "$TEMP_MATCHES" 2>/dev/null

if [ ! -s "$TEMP_MATCHES" ]; then
    print_error "❌ NO EMAIL ACTIVITY FOUND for $check_label"
    echo ""
    echo "This means:"
    echo "  • No emails sent TO this $check_label"
    echo "  • No emails sent FROM this $check_label"
    echo "  • No delivery attempts logged"
    echo ""
    print_warning "Possible reasons:"
    echo "  1. Email address/domain doesn't exist on this server"
    echo "  2. No email activity in the last $hours hours"
    echo "  3. Emails are going to a different mail server"
    echo ""

    # Check if domain exists
    if [ "$check_type" = "2" ]; then
        if grep -q "$target" /etc/localdomains 2>/dev/null || grep -q "$target" /etc/userdomains 2>/dev/null; then
            print_info "✓ Domain $target IS configured on this server"
        else
            print_warning "⚠ Domain $target NOT found in local domains"
        fi
    fi

    rm -f "$TEMP_MATCHES"
    exit 0
fi

total_lines=$(wc -l < "$TEMP_MATCHES")
print_success "✓ Found $total_lines log entries for $check_label"
echo ""

################################################################################
# Categorize activity
################################################################################

print_header "📊 Activity Summary"
echo ""

# Count different types
delivered=$(grep -ci "=> .*$search_pattern\|delivered.*$search_pattern" "$TEMP_MATCHES" || echo 0)
sent=$(grep -ci "<=.*$search_pattern" "$TEMP_MATCHES" || echo 0)
bounced=$(grep -ci "bounce.*$search_pattern\|failed.*$search_pattern\|550.*$search_pattern" "$TEMP_MATCHES" || echo 0)
deferred=$(grep -ci "deferred.*$search_pattern\|retry.*$search_pattern\|temporarily rejected" "$TEMP_MATCHES" || echo 0)
rejected=$(grep -ci "rejected.*$search_pattern\|denied.*$search_pattern\|blocked.*$search_pattern" "$TEMP_MATCHES" || echo 0)
spf_fail=$(grep -ci "SPF.*fail.*$search_pattern" "$TEMP_MATCHES" || echo 0)
dkim_fail=$(grep -ci "DKIM.*fail.*$search_pattern" "$TEMP_MATCHES" || echo 0)

if [ "$delivered" -gt 0 ]; then
    print_success "✅ Delivered: $delivered emails successfully delivered"
fi

if [ "$sent" -gt 0 ]; then
    print_info "📤 Sent: $sent emails sent FROM this $check_label"
fi

if [ "$bounced" -gt 0 ]; then
    print_error "❌ Bounced: $bounced emails bounced/failed"
fi

if [ "$deferred" -gt 0 ]; then
    print_warning "⏸  Deferred: $deferred emails temporarily delayed"
fi

if [ "$rejected" -gt 0 ]; then
    print_error "🚫 Rejected: $rejected emails blocked/rejected"
fi

if [ "$spf_fail" -gt 0 ]; then
    print_warning "⚠  SPF Failures: $spf_fail authentication failures"
fi

if [ "$dkim_fail" -gt 0 ]; then
    print_warning "⚠  DKIM Failures: $dkim_fail signature failures"
fi

echo ""

################################################################################
# Show verdict
################################################################################

print_header "🔍 Diagnostic Result"
echo ""

if [ "$delivered" -gt 0 ] && [ "$bounced" -eq 0 ] && [ "$rejected" -eq 0 ]; then
    print_success "✅ EMAIL IS WORKING PROPERLY"
    echo ""
    echo "Evidence: $delivered successful deliveries in the last $hours hours"
    echo "No bounces or rejections detected"
    echo "Proof shown below with timestamps"
    echo ""
elif [ "$delivered" -gt 0 ] && [ "$bounced" -gt 0 ]; then
    print_warning "⚠  EMAIL PARTIALLY WORKING"
    echo ""
    echo "Some emails delivered ($delivered) but some failed ($bounced)"
    echo "Check bounce reasons below for details"
    echo ""
elif [ "$bounced" -gt 0 ] || [ "$rejected" -gt 0 ]; then
    print_error "❌ EMAIL HAS PROBLEMS"
    echo ""
    echo "Emails are being rejected or bouncing"
    echo "See details below for why"
    echo ""
elif [ "$deferred" -gt 0 ]; then
    print_warning "⏸  EMAIL DELAYED"
    echo ""
    echo "Emails are being deferred (temporary failures)"
    echo "This usually resolves itself"
    echo ""
else
    print_info "📬 EMAILS SENT, AWAITING CONFIRMATION"
    echo ""
    echo "Emails were sent but no delivery confirmation yet"
    echo "Check again in a few minutes"
    echo ""
fi

################################################################################
# Show recent activity samples
################################################################################

if [ "$delivered" -gt 0 ]; then
    print_header "✅ Recent Successful Deliveries (last 5 from past $hours hours)"
    echo ""
    print_info "PROOF - These emails were delivered recently:"
    echo ""
    grep -i "=> .*$search_pattern\|delivered.*$search_pattern" "$TEMP_MATCHES" | tail -5 | while read line; do
        # Extract timestamp if present
        timestamp=$(echo "$line" | grep -oE '[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}|[A-Z][a-z]{2} [0-9]+ [0-9]{2}:[0-9]{2}:[0-9]{2}' | head -1)
        if [ -n "$timestamp" ]; then
            echo -e "  ${GREEN}[$timestamp]${NC} $line"
        else
            echo "  $line"
        fi
    done
    echo ""
fi

if [ "$bounced" -gt 0 ]; then
    print_header "❌ Recent Bounces/Failures (last 5 from past $hours hours)"
    echo ""
    print_warning "PROOF - These emails failed recently:"
    echo ""
    grep -i "bounce.*$search_pattern\|failed.*$search_pattern\|550.*$search_pattern" "$TEMP_MATCHES" | tail -5 | while read line; do
        timestamp=$(echo "$line" | grep -oE '[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}|[A-Z][a-z]{2} [0-9]+ [0-9]{2}:[0-9]{2}:[0-9]{2}' | head -1)
        if [ -n "$timestamp" ]; then
            echo -e "  ${RED}[$timestamp]${NC} $line"
        else
            echo "  $line"
        fi
    done
    echo ""

    # Extract bounce reasons
    print_header "Common Bounce Reasons"
    echo ""
    grep -i "bounce\|550\|fail" "$TEMP_MATCHES" | grep -oE "550 .*|User unknown|Mailbox.*full|Relay.*denied|blocked" | sort | uniq -c | sort -rn | head -5
    echo ""
fi

if [ "$rejected" -gt 0 ]; then
    print_header "🚫 Recent Rejections (last 5)"
    echo ""
    grep -i "rejected.*$search_pattern\|denied.*$search_pattern\|blocked.*$search_pattern" "$TEMP_MATCHES" | tail -5 | while read line; do
        echo "  $line"
    done
    echo ""
fi

if [ "$spf_fail" -gt 0 ] || [ "$dkim_fail" -gt 0 ]; then
    print_header "⚠  Authentication Issues"
    echo ""
    if [ "$spf_fail" -gt 0 ]; then
        echo "SPF failures detected:"
        grep -i "SPF.*fail" "$TEMP_MATCHES" | head -3
        echo ""
    fi
    if [ "$dkim_fail" -gt 0 ]; then
        echo "DKIM failures detected:"
        grep -i "DKIM.*fail" "$TEMP_MATCHES" | head -3
        echo ""
    fi
fi

################################################################################
# Recommendations
################################################################################

print_header "💡 Recommendations"
echo ""

if [ "$bounced" -gt 0 ]; then
    echo "To fix bounces:"
    echo "  1. Verify the recipient email address is correct"
    echo "  2. Check if recipient mailbox is full"
    echo "  3. Ensure domain DNS is configured properly"
    echo ""
fi

if [ "$rejected" -gt 0 ]; then
    echo "To fix rejections:"
    echo "  1. Check if server IP is blacklisted (use Blacklist Check tool)"
    echo "  2. Verify SPF/DKIM/DMARC records are correct"
    echo "  3. Check if recipient is blocking your domain"
    echo ""
fi

if [ "$spf_fail" -gt 0 ]; then
    echo "To fix SPF failures:"
    echo "  1. Add this server's IP to domain's SPF record"
    echo "  2. Use SPF/DKIM/DMARC Check tool for details"
    echo ""
fi

################################################################################
# Save full report
################################################################################

REPORT_FILE="/tmp/email_diag_${target//[@.]/_}_$(date +%Y%m%d_%H%M%S).txt"
cp "$TEMP_MATCHES" "$REPORT_FILE"

print_info "Full log saved to: $REPORT_FILE"
echo ""

# Cleanup
rm -f "$TEMP_MATCHES"