package overlay

import (
	"testing"

	"github.com/novox/mesh-controller/internal/catalogue"
)

// The network module's `/etc/hosts` is a roster template like any module's (novox/hq: the graph is
// the control plane's, the format is the module's). These pin the format that used to be a Go
// formatter in the control plane, so the file a machine gets does not change with the mechanism:
// the loopback floor, the Debian self-name line, the machine's own line marked and at its mesh
// address, one line per machine, every served name (issue 111).
func hostsFor(t *testing.T, node string, every map[string]string) string {
	t.Helper()
	m := catalogue.Manifest{Module: "net", Facts: map[string]catalogue.RosterFile{
		"node-names": {Path: "/etc/hosts", Template: hostsTemplate},
	}}
	given, err := catalogue.FactsInto(m, catalogue.Resolution{Node: node}, every, every, "")
	if err != nil {
		t.Fatal(err)
	}
	return given[0]["content"].(string)
}

func TestTheHostsFileIsThisExactly(t *testing.T) {
	got := hostsFor(t, "homer", map[string]string{"homer.internal": "10.42.0.1", "marge.internal": "10.42.0.2"})
	want := "# Generated by the mesh. Do not edit — this file is replaced whenever a machine\n" +
		"# joins or leaves, and an edit would survive until then and vanish.\n\n" +
		"127.0.0.1\tlocalhost\n" +
		"::1\t\tlocalhost ip6-localhost ip6-loopback\n" +
		"127.0.1.1\thomer\n\n" +
		"10.42.0.1\thomer.internal\thomer\t# this machine\n" +
		"10.42.0.2\tmarge.internal\tmarge\n"
	if got != want {
		t.Fatalf("the hosts file changed with the mechanism:\ngot:\n%q\nwant:\n%q", got, want)
	}
}

// With no node named there is no `127.0.1.1` self-line — but the blank line before the machines
// stays, exactly as the old formatter wrote it unconditionally.
func TestTheHostsFileWithoutASelfNameKeepsItsShape(t *testing.T) {
	got := hostsFor(t, "", map[string]string{"homer.internal": "10.42.0.1"})
	want := "# Generated by the mesh. Do not edit — this file is replaced whenever a machine\n" +
		"# joins or leaves, and an edit would survive until then and vanish.\n\n" +
		"127.0.0.1\tlocalhost\n" +
		"::1\t\tlocalhost ip6-localhost ip6-loopback\n\n" +
		"10.42.0.1\thomer.internal\thomer\n"
	if got != want {
		t.Fatalf("the hosts file without a self-name changed shape:\ngot:\n%q\nwant:\n%q", got, want)
	}
}