package catalogue_test

import (
	"encoding/json"
	"strings"
	"testing"

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

// The manifests the control plane actually ships, resolved.
//
// Written because the earlier tests built their own manifests and passed while the real one was
// missing a claim — a whole mechanism could have been absent from what ships and every test would
// still have been green.

func provided(t *testing.T) map[string]catalogue.Manifest {
	t.Helper()
	out := map[string]catalogue.Manifest{}
	for _, raw := range []map[string]any{
		overlay.Manifest(),
	} {
		b, err := json.Marshal(raw)
		if err != nil {
			t.Fatal(err)
		}
		m, err := catalogue.ParseManifest(b)
		if err != nil {
			t.Fatalf("a manifest this control plane ships is not valid: %v", err)
		}
		out[m.Module] = m
	}
	return out
}

func TestTheShippedPrivateNetworkResolvesOnItsOwn(t *testing.T) {
	// **Assigned directly** (novox/hq ADR 0226): the `networking` bundle that required it is
	// retired, so the private network's own module is what a machine is given, and it must need
	// nothing the control plane does not ship beside it.
	got, err := catalogue.Resolve(provided(t), []string{overlay.Name}, catalogue.Node{Name: "workstation", Site: "house"}, catalogue.World{})
	if err != nil {
		t.Fatalf("assigning %s does not work out of the box: %v", overlay.Name, err)
	}
	if len(got.Modules) != 1 || got.Modules[0].Module != overlay.Name {
		t.Fatalf("assigning %s brought %v", overlay.Name, got.Modules)
	}

	// **The network writes no names** (novox/hq ADR 0199): /etc/hosts is the hosts seat holder's
	// file, and the mesh's resolver answers the machines' names. No fact of the network's module
	// may name that file.
	for _, m := range got.Modules {
		for name, f := range m.Facts {
			if f.Path == "/etc/hosts" {
				t.Fatalf("the network's provider still writes /etc/hosts, as its %q fact", name)
			}
		}
	}
}

func TestTheControlPlaneShipsNoNetworkingBundle(t *testing.T) {
	// ADR 0226: one module for the one private network. A bundle shipped beside it again would be
	// a second name every machine carries for the same thing.
	shipped := provided(t)
	if len(shipped) != 1 {
		t.Fatalf("the control plane ships %d modules, want only %s", len(shipped), overlay.Name)
	}
	if _, ok := shipped["networking"]; ok {
		t.Fatal("the retired networking bundle is shipped again")
	}
}

func TestARefusalForWantOfThePrivateNetworkNamesItsModule(t *testing.T) {
	// The hint in a refusal is a string in the resolver rather than an import of this package. It
	// named `networking` until ADR 0226; a hint naming a module nobody ships sends a person to
	// assign something that does not exist.
	shelf := map[string]catalogue.Manifest{
		"app":      {Module: "app", Version: "1", Requires: []string{"postgres-database"}},
		"postgres": {Module: "postgres", Version: "1", Provides: catalogue.FromAnywhere("postgres-database")},
	}
	_, err := catalogue.Resolve(shelf, []string{"app"}, catalogue.Node{Name: "workstation"},
		catalogue.World{Offered: map[string][]catalogue.Provider{
			"postgres-database": {{Node: "anchor", At: "anchor.internal"}}}})
	if err == nil {
		t.Fatal("an app off the private network was pointed at a database on it")
	}
	if !strings.Contains(err.Error(), "assign "+overlay.Name) {
		t.Fatalf("the refusal does not name the private network's module %s: %v", overlay.Name, err)
	}
}

func TestAnotherVPNIsChosenByAssigningItInstead(t *testing.T) {
	// What the bundle was for, kept without it: a machine given another VPN answers
	// private-network from that VPN, and WireGuard is not dragged in by anything.
	shipped := provided(t)
	shelf := withTailscale(shipped)
	shelf["needs-network"] = catalogue.Manifest{Module: "needs-network", Version: "1",
		Requires: []string{overlay.Requirement}}
	got, err := catalogue.Resolve(shelf, []string{"needs-network", "tailscale"},
		catalogue.Node{Name: "workstation", Site: "house"}, catalogue.World{})
	if err != nil {
		t.Fatalf("choosing another VPN was refused: %v", err)
	}
	for _, m := range got.Modules {
		if m.Module == overlay.Name {
			t.Fatalf("the other VPN was chosen and WireGuard came anyway: %v", got.Modules)
		}
	}
}

func TestTwoVPNsAssignedTogetherStillCollide(t *testing.T) {
	// The claim still guards the case it was always for: both assigned EXPLICITLY, which is a
	// machine with two private networks and a coin toss about which one a peer reaches it on.
	shipped := provided(t)
	_, err := catalogue.Resolve(
		withTailscale(shipped),
		[]string{overlay.Name, "tailscale"},
		catalogue.Node{Name: "workstation", Site: "house"}, catalogue.World{})
	if err == nil {
		t.Fatal("a machine was given two private networks and nobody was told")
	}
	if !strings.Contains(err.Error(), overlay.TheNetwork) {
		t.Fatalf("the refusal does not say what collided: %v", err)
	}
}

// The names-need-addressing test went with the names module: names are a fact now, and a machine
// the mesh cannot place is simply left out of the file (facts_test.go) — which is the same
// protection, enforced where the file is written rather than by a provision refusing.

func withTailscale(shelf map[string]catalogue.Manifest) map[string]catalogue.Manifest {
	out := map[string]catalogue.Manifest{}
	for k, v := range shelf {
		out[k] = v
	}
	// Deliberately without name-resolution of its own, which is the case that used to install
	// both VPNs: the names then needed the mesh's addressing, and only WireGuard has it.
	out["tailscale"] = catalogue.Manifest{
		Module: "tailscale", Version: "1",
		Provides: catalogue.Offers(overlay.Requirement),
		Claims:   []catalogue.Claim{{Name: overlay.TheNetwork, Scope: catalogue.ScopeNode}},
	}
	return out
}