#!/bin/bash

# MongoDB Log Rotation Script for Wekan Snap
# This script handles log rotation for MongoDB logs in the Wekan snap environment

set -e

# Source settings if available, otherwise use defaults
if [ -f "$SNAP/bin/wekan-read-settings" ]; then
    source $SNAP/bin/wekan-read-settings
else
    # Default values when wekan-read-settings is not available
    SNAP_COMMON="/var/snap/wekan/common"
    SNAP_NAME="wekan"
fi

# Configuration
MONGODB_LOG="${SNAP_COMMON}/mongodb.log"
MAX_SIZE_MB=100
KEEP_COPIES=10
COMPRESS_LOGS=true

# Logging functions
log_message() {
    local message="$1"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    echo "[$timestamp] $message"
}

log_error() {
    local message="$1"
    log_message "ERROR: $message"
}

log_success() {
    local message="$1"
    log_message "SUCCESS: $message"
}

log_warning() {
    local message="$1"
    log_message "WARNING: $message"
}

# Check if log file exists and is large enough to rotate
check_rotation_needed() {
    if [ ! -f "$MONGODB_LOG" ]; then
        log_message "MongoDB log file not found: $MONGODB_LOG"
        return 1
    fi
    
    # Get log file size in MB
    local log_size_mb=$(du -m "$MONGODB_LOG" | cut -f1)
    
    if [ "$log_size_mb" -lt "$MAX_SIZE_MB" ]; then
        log_message "MongoDB log size (${log_size_mb}MB) is below rotation threshold (${MAX_SIZE_MB}MB)"
        return 1
    fi
    
    log_message "MongoDB log size (${log_size_mb}MB) exceeds rotation threshold (${MAX_SIZE_MB}MB)"
    return 0
}

# Rotate MongoDB log file
rotate_log() {
    local mongodb_log="$1"
    local max_size_mb="$2"
    local keep_copies="$3"
    local compress="$4"
    
    log_message "Starting MongoDB log rotation"
    
    # Create rotated log file with timestamp
    local timestamp=$(date +%Y%m%d-%H%M%S)
    local rotated_log="${mongodb_log}.${timestamp}"
    
    # Copy current log to rotated file
    if cp "$mongodb_log" "$rotated_log"; then
        log_message "Created rotated log file: $rotated_log"
        
        # Truncate original log file
        if > "$mongodb_log"; then
            log_message "Truncated original log file"
        else
            log_error "Failed to truncate original log file"
            return 1
        fi
        
        # Compress rotated log file if requested
        if [ "$compress" = "true" ]; then
            if gzip "$rotated_log"; then
                log_message "Compressed rotated log file: ${rotated_log}.gz"
            else
                log_warning "Failed to compress rotated log file"
            fi
        fi
        
        # Clean up old rotated logs (keep only specified number)
        local old_logs=$(ls -t "${mongodb_log}".* 2>/dev/null | tail -n +$((keep_copies + 1)))
        if [ -n "$old_logs" ]; then
            echo "$old_logs" | xargs rm -f
            log_message "Cleaned up old rotated log files"
        fi
        
        log_success "MongoDB log rotation completed successfully"
        return 0
    else
        log_error "Failed to create rotated log file"
        return 1
    fi
}

# Show log file statistics
show_log_stats() {
    if [ ! -f "$MONGODB_LOG" ]; then
        log_message "MongoDB log file not found: $MONGODB_LOG"
        return 1
    fi
    
    local log_size_mb=$(du -m "$MONGODB_LOG" | cut -f1)
    local log_lines=$(wc -l < "$MONGODB_LOG" 2>/dev/null || echo "0")
    local rotated_count=$(ls -1 "${MONGODB_LOG}".* 2>/dev/null | wc -l)
    
    log_message "MongoDB Log Statistics:"
    log_message "  Current log size: ${log_size_mb}MB"
    log_message "  Current log lines: ${log_lines}"
    log_message "  Rotated log files: ${rotated_count}"
    log_message "  Rotation threshold: ${MAX_SIZE_MB}MB"
    log_message "  Keep copies: ${KEEP_COPIES}"
}

# Force rotation regardless of size
force_rotation() {
    log_message "Force rotating MongoDB log file"
    
    if [ ! -f "$MONGODB_LOG" ]; then
        log_error "MongoDB log file not found: $MONGODB_LOG"
        return 1
    fi
    
    rotate_log "$MONGODB_LOG" "$MAX_SIZE_MB" "$KEEP_COPIES" "$COMPRESS_LOGS"
}

# Main function
main() {
    local action="${1:-check}"
    
    case "$action" in
        "check")
            log_message "Checking if MongoDB log rotation is needed"
            if check_rotation_needed; then
                log_message "Log rotation is needed"
                rotate_log "$MONGODB_LOG" "$MAX_SIZE_MB" "$KEEP_COPIES" "$COMPRESS_LOGS"
            else
                log_message "Log rotation is not needed"
            fi
            ;;
        "force")
            force_rotation
            ;;
        "stats")
            show_log_stats
            ;;
        "help"|"-h"|"--help")
            echo "Usage: $0 [check|force|stats|help]"
            echo ""
            echo "Commands:"
            echo "  check  - Check if rotation is needed and rotate if so (default)"
            echo "  force  - Force rotation regardless of log size"
            echo "  stats  - Show log file statistics"
            echo "  help   - Show this help message"
            echo ""
            echo "Configuration:"
            echo "  Log file: $MONGODB_LOG"
            echo "  Max size: ${MAX_SIZE_MB}MB"
            echo "  Keep copies: $KEEP_COPIES"
            echo "  Compress: $COMPRESS_LOGS"
            ;;
        *)
            log_error "Unknown action: $action"
            echo "Use '$0 help' for usage information"
            exit 1
            ;;
    esac
}

# Run main function
main "$@"