package http

import "strings"

// JoinPath returns an absolute URL path composed of the two paths provided.
// Enforces that the returned path begins with '/'. If added path is empty the
// returned path suffix will match the first parameter suffix.
func JoinPath(a, b string) string {
	if len(a) == 0 {
		a = "/"
	} else if a[0] != '/' {
		a = "/" + a
	}

	if len(b) != 0 && b[0] == '/' {
		b = b[1:]
	}

	if len(b) != 0 && len(a) > 1 && a[len(a)-1] != '/' {
		a = a + "/"
	}

	return a + b
}

// JoinRawQuery returns an absolute raw query expression. Any duplicate '&'
// will be collapsed to single separator between values.
func JoinRawQuery(a, b string) string {
	a = strings.TrimFunc(a, isAmpersand)
	b = strings.TrimFunc(b, isAmpersand)

	if len(a) == 0 {
		return b
	}
	if len(b) == 0 {
		return a
	}

	return a + "&" + b
}

func isAmpersand(v rune) bool {
	return v == '&'
}