package config

import (
	"fmt"
	"strconv"
	"strings"
)

type PortGroup struct {
	Proto string   `yaml:"proto"`
	Ports PortSpec `yaml:"ports"`
}

// ParsedPorts returns individual port numbers and ranges as (start, end) pairs.
func (pg *PortGroup) ParsedPorts() (singles []uint16, ranges [][2]uint16, err error) {
	for _, p := range pg.Ports {
		if strings.Contains(p, "-") {
			parts := strings.SplitN(p, "-", 2)
			start, err := strconv.ParseUint(parts[0], 10, 16)
			if err != nil {
				return nil, nil, fmt.Errorf("invalid port range start %q: %w", parts[0], err)
			}
			end, err := strconv.ParseUint(parts[1], 10, 16)
			if err != nil {
				return nil, nil, fmt.Errorf("invalid port range end %q: %w", parts[1], err)
			}
			if start > end {
				return nil, nil, fmt.Errorf("port range %d-%d: start > end", start, end)
			}
			ranges = append(ranges, [2]uint16{uint16(start), uint16(end)})
		} else {
			port, err := strconv.ParseUint(p, 10, 16)
			if err != nil {
				return nil, nil, fmt.Errorf("invalid port %q: %w", p, err)
			}
			singles = append(singles, uint16(port))
		}
	}
	return singles, ranges, nil
}

func (c *Config) validatePortGroups() error {
	for name, pg := range c.PortGroups {
		if pg.Proto == "" {
			return fmt.Errorf("portgroup %q: proto required", name)
		}
		if pg.Proto != "tcp" && pg.Proto != "udp" {
			return fmt.Errorf("portgroup %q: proto must be tcp or udp, got %q", name, pg.Proto)
		}
		if len(pg.Ports) == 0 {
			return fmt.Errorf("portgroup %q: at least one port required", name)
		}
		if _, _, err := pg.ParsedPorts(); err != nil {
			return fmt.Errorf("portgroup %q: %w", name, err)
		}
	}
	return nil
}