package awgserver

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

// HeaderRange represents an H1-H4 header value range for AWG packet detection.
type HeaderRange struct {
	Min, Max uint32
}

// Contains checks if value v falls within the range [Min, Max].
func (h HeaderRange) Contains(v uint32) bool {
	return v >= h.Min && v <= h.Max
}

func (h HeaderRange) String() string {
	if h.Min == h.Max {
		return fmt.Sprintf("%d", h.Min)
	}
	return fmt.Sprintf("%d-%d", h.Min, h.Max)
}

// ParseHeaderRange parses a string like "50000-100000" or "50000" into a HeaderRange.
func ParseHeaderRange(s string) (HeaderRange, error) {
	if strings.Contains(s, "-") {
		parts := strings.SplitN(s, "-", 2)
		min, err := strconv.ParseUint(parts[0], 10, 32)
		if err != nil {
			return HeaderRange{}, fmt.Errorf("parse min: %w", err)
		}
		max, err := strconv.ParseUint(parts[1], 10, 32)
		if err != nil {
			return HeaderRange{}, fmt.Errorf("parse max: %w", err)
		}
		return HeaderRange{Min: uint32(min), Max: uint32(max)}, nil
	}
	v, err := strconv.ParseUint(s, 10, 32)
	if err != nil {
		return HeaderRange{}, fmt.Errorf("parse value: %w", err)
	}
	return HeaderRange{Min: uint32(v), Max: uint32(v)}, nil
}