#!/usr/bin/env bash
set -uo pipefail

DEFAULT_MIN_PORT=8000
DEFAULT_MAX_PORT=64000

usage() {
    cat <<EOF
Usage: $(basename "$0") [OPTIONS] [COMMAND]

Manage and check ports for LoadBalancer services in k8s yaml files.

Commands:
  next               Find the next available port greater than MIN (default: 8000)
  check PORT        Check if a specific port is available
  list               List all ports in use

Options:
  --from MIN         Minimum port to check from (default: $DEFAULT_MIN_PORT)
  --to MAX           Maximum port to check to (default: $DEFAULT_MAX_PORT)
  -h, --help         Show this help message
  -v                 Verbose output

Examples:
  $(basename "$0") next                           # Find next available port > 8000
  $(basename "$0") next --from 8200 --to 8300     # Find next available port in range
  $(basename "$0") check 8008                     # Check if port 8008 is available
  $(basename "$0") check 9000 --from 9000         # Check if port 9000 is available in range
  $(basename "$0") list                            # List all ports in use
EOF
}

VERBOSE=0
COMMAND=""
MIN_PORT=$DEFAULT_MIN_PORT
MAX_PORT=$DEFAULT_MAX_PORT
CHECK_PORT=""

while [[ $# -gt 0 ]]; do
    case "$1" in
        -h|--help)
            usage
            exit 0
            ;;
        -v)
            VERBOSE=1
            shift
            ;;
        --from)
            MIN_PORT="$2"
            shift 2
            ;;
        --to)
            MAX_PORT="$2"
            shift 2
            ;;
        next|check|list)
            COMMAND="$1"
            shift
            ;;
        -*)
            echo "Error: Unknown option: $1" >&2
            usage >&2
            exit 1
            ;;
        *)
            if [[ "$1" =~ ^[0-9]+$ ]]; then
                if [[ "$COMMAND" == "check" ]] || [[ -z "$COMMAND" ]]; then
                    CHECK_PORT="$1"
                    COMMAND="check"
                else
                    echo "Error: Unexpected argument: $1" >&2
                    usage >&2
                    exit 1
                fi
            else
                echo "Error: Unexpected argument: $1" >&2
                usage >&2
                exit 1
            fi
            shift
            ;;
    esac
done

if [[ -z "$COMMAND" ]]; then
    echo "Error: No command specified" >&2
    usage >&2
    exit 1
fi

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
K8S_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"

collect_ports() {
    PORTS=()

    while IFS= read -r file || [[ -n "$file" ]]; do
        if [[ ! -f "$file" ]]; then
            continue
        fi

        if ! grep -q "LoadBalancer" "$file" 2>/dev/null; then
            continue
        fi

        lb_port=$(yq -r '.. | objects | select(.type == "LoadBalancer") | select(.port != null) | .port // empty' "$file" 2>/dev/null || true)
        if [[ -n "$lb_port" ]] && [[ "$lb_port" != "null" ]] && [[ "$lb_port" =~ ^[0-9]+$ ]]; then
            PORTS+=("$lb_port")
            [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Found .port $lb_port in $file"
        fi

        service_port_http=$(yq -r '.. | objects | select(.type == "LoadBalancer") | .servicePortHttp // empty' "$file" 2>/dev/null || true)
        if [[ -n "$service_port_http" ]] && [[ "$service_port_http" != "null" ]] && [[ "$service_port_http" =~ ^[0-9]+$ ]]; then
            PORTS+=("$service_port_http")
            [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Found servicePortHttp $service_port_http in $file"
        fi

        service_port_https=$(yq -r '.. | objects | select(.type == "LoadBalancer") | .servicePortHttps // empty' "$file" 2>/dev/null || true)
        if [[ -n "$service_port_https" ]] && [[ "$service_port_https" != "null" ]] && [[ "$service_port_https" =~ ^[0-9]+$ ]]; then
            PORTS+=("$service_port_https")
            [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Found servicePortHttps $service_port_https in $file"
        fi

        service_dns_port=$(yq -r '.. | objects | select(.type == "LoadBalancer") | .dns.port // empty' "$file" 2>/dev/null || true)
        if [[ -n "$service_dns_port" ]] && [[ "$service_dns_port" != "null" ]] && [[ "$service_dns_port" =~ ^[0-9]+$ ]]; then
            PORTS+=("$service_dns_port")
            [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Found dns.port $service_dns_port in $file"
        fi
    done < <(find "$K8S_DIR/k8s" -name "*.yaml" -type f 2>/dev/null) || true

    if command -v kubectl &>/dev/null && kubectl cluster-info &>/dev/null 2>&1; then
        [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Querying kubectl for LoadBalancer services..."
        while IFS= read -r line || [[ -n "$line" ]]; do
            ports_str=$(echo "$line" | awk '{print $6}')
            svc_name=$(echo "$line" | awk '{print $2}')
            while IFS=',' read -ra port_entries || [[ -n "${port_entries[*]}" ]]; do
                for entry in "${port_entries[@]}"; do
                    port=$(echo "$entry" | cut -d: -f1 | cut -d/ -f1)
                    if [[ -n "$port" ]] && [[ "$port" =~ ^[0-9]+$ ]]; then
                        PORTS+=("$port")
                        [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Found kubectl port $port for $svc_name"
                    fi
                done
            done <<< "$ports_str"
        done < <(kubectl get svc -A --no-headers 2>/dev/null | grep LoadBalancer || true)
    fi
}

is_port_in_use() {
    local port="$1"
    [[ " ${PORTS[*]} " =~ ${port} ]]
}

run_command() {
    collect_ports

    if [[ ${#PORTS[@]} -eq 0 ]]; then
        [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] No ports found in use"
    else
        [[ $VERBOSE -eq 1 ]] && echo "[DEBUG] Ports in use: ${PORTS[*]}"
    fi

    case "$COMMAND" in
        next)
            next_port=$MIN_PORT
            while [[ $next_port -le $MAX_PORT ]]; do
                if ! is_port_in_use "$next_port"; then
                    echo "$next_port"
                    return 0
                fi
                next_port=$((next_port + 1))
            done
            echo "Error: No available port found between $MIN_PORT and $MAX_PORT" >&2
            return 1
            ;;
        check)
            if [[ -z "$CHECK_PORT" ]]; then
                echo "Error: PORT is required for check command" >&2
                return 1
            fi
            if ! [[ "$CHECK_PORT" =~ ^[0-9]+$ ]]; then
                echo "Error: PORT must be a number" >&2
                return 1
            fi
            if [[ "$CHECK_PORT" -lt 1 ]] || [[ "$CHECK_PORT" -gt 65535 ]]; then
                echo "Error: PORT must be between 1 and 65535" >&2
                return 1
            fi
            if [[ "$CHECK_PORT" -lt "$MIN_PORT" ]] || [[ "$CHECK_PORT" -gt "$MAX_PORT" ]]; then
                echo "Error: PORT $CHECK_PORT is outside the check range ($MIN_PORT - $MAX_PORT)" >&2
                return 1
            fi
            if is_port_in_use "$CHECK_PORT"; then
                echo "PORT $CHECK_PORT IS IN USE"
                return 1
            else
                echo "PORT $CHECK_PORT IS AVAILABLE"
                return 0
            fi
            ;;
        list)
            if [[ ${#PORTS[@]} -eq 0 ]]; then
                echo "No ports in use"
            else
                printf '%s\n' "${PORTS[@]}" | sort -n -u
            fi
            ;;
    esac
}

run_command