package catalogue

import (
	"encoding/json"
	"fmt"
	"os"
	"reflect"
	"strings"
	"testing"
)

// The catalogue's foundation modules as they are, parsed by the real parser (novox/hq ADR 0100):
// the store and the broker say which of their ports the mesh guards on an adopted node, and the
// filter module loads its table through a unit of its own whose stop deletes only that table.
func catalogueManifest(t *testing.T, module string) Manifest {
	t.Helper()
	raw, err := os.ReadFile("../../../mesh-catalog/modules/" + module + "/module.json")
	if err != nil {
		t.Skipf("the catalogue is not beside this checkout: %v", err)
	}
	m, err := ParseManifest(raw)
	if err != nil {
		t.Fatalf("%s does not parse:\n%v", module, err)
	}
	return m
}

func TestTheStoreAndTheBrokerSayWhatTheMeshGuards(t *testing.T) {
	if got := catalogueManifest(t, "postgres").Guards; !reflect.DeepEqual(got, []int{5432}) {
		t.Errorf("postgres guards %v; the store's port must be refused from outside", got)
	}
	if got := catalogueManifest(t, "lavinmq").Guards; !reflect.DeepEqual(got, []int{15672}) {
		t.Errorf("lavinmq guards %v; the management port must be refused from outside", got)
	}
}

func TestTheFilterModuleNeverFlushesTheRuleset(t *testing.T) {
	m := catalogueManifest(t, "nftables")
	var unit, stock, load map[string]any
	for _, r := range m.Resources {
		switch r["id"] {
		case "unit":
			unit = r
		case "stock-unit-stop":
			stock = r
		case "load":
			load = r
		}
	}
	if load == nil || load["unit"] != "mesh-filter.service" {
		t.Fatalf("the filter is not loaded by its own unit: %v", load)
	}
	content, _ := unit["content"].(string)
	if unit == nil || unit["path"] != "/etc/systemd/system/mesh-filter.service" {
		t.Fatalf("the filter's unit is not written: %v", unit)
	}
	if strings.Contains(content, "flush") {
		t.Fatalf("stopping the filter flushes the whole ruleset — the runtime's and the found "+
			"firewall's with it:\n%s", content)
	}
	if !strings.Contains(content, "ExecStop=nft delete table inet mesh\n") ||
		!strings.Contains(content, "ExecStart=nft -f "+m.Filtering.Into+"\n") {
		t.Fatalf("the unit does not load the computed rule set and delete only its own table:\n%s",
			content)
	}
	// A node converged before the filter had its own unit still has the stock nftables.service
	// enabled, whose stop flushes the whole ruleset: a drop-in makes it delete only the mesh's
	// table, and the load is restarted on it so the host reloads units and the drop-in is read.
	if stock == nil || stock["path"] != "/etc/systemd/system/nftables.service.d/mesh.conf" ||
		!strings.HasSuffix(fmt.Sprint(stock["content"]),
			"[Service]\nExecStop=\nExecStop=nft delete table inet mesh\n") {
		t.Fatalf("the stock unit's stop is not replaced with deleting the mesh's table: %v", stock)
	}
	// A changed rule set is RELOADED — ExecReload replaces the table in one `nft -f`, so the node
	// is never unfiltered — and only the units themselves restart it, which is the one change a
	// reload cannot carry.
	if !reflect.DeepEqual(load["reload-on"], []any{"filtering"}) {
		t.Fatalf("the filter is restarted rather than reloaded when its rules change, leaving the "+
			"node unfiltered in between: %v", load)
	}
	if !reflect.DeepEqual(load["restart-on"], []any{"unit", "stock-unit-stop"}) {
		t.Fatalf("the filter is not restarted when its unit or the stock unit's drop-in changes: %v",
			load["restart-on"])
	}
}

// The package registry's port is the node's, like every other foundation port (novox/hq
// 04-ISSUES/085, ADR 0100). Two halves, because the forge is reached two ways: through what the
// module that serves it says it serves, and — for the genesis window, before any module provides
// `package-registry` at all — through the one binding the builder carries instead of resolving.

func TestTheForgesPortIsGivenLikeAnyOtherProvidersPort(t *testing.T) {
	forge := catalogueManifest(t, "gitea")

	// The catalogue's number is a default and the node's setting moves it.
	given, err := GivenPorts(forge, []Layer{{From: "anchor",
		Values: map[string]any{PortsSetting: map[string]any{"3000": float64(3100)}}}})
	if err != nil {
		t.Fatalf("the forge's port cannot be given on a node: %v", err)
	}
	if given[3000] != 3100 {
		t.Fatalf("the forge was given %v", given)
	}

	// And every consumer of the package registry is told where the machine actually put it,
	// because that is read from what the forge serves rather than written in the consumer.
	if got := ServedOn(forge, "package-registry", given)["port"]; got != 3100 {
		t.Errorf("the package registry is served on %v, not the port this node gave it", got)
	}
	if got := ServedOn(forge, "package-registry", nil)["port"]; got != float64(3000) {
		t.Errorf("without a setting the forge serves %v, not the catalogue's port", got)
	}
}

// bindingIn is the package binding the builder carries, as the machine would receive it.
func bindingIn(t *testing.T, m Manifest, layers []Layer) map[string]any {
	t.Helper()
	for _, r := range m.Resources {
		if fmt.Sprint(r["id"]) != "package-binding" {
			continue
		}
		settled, err := ApplySettings(r, layers)
		if err != nil {
			t.Fatalf("the builder's package binding refused %v: %v", layers, err)
		}
		if settled["merge"] != nil || settled["protected"] != nil {
			t.Fatal("the host would be sent fields it does not know")
		}
		var out map[string]any
		if err := json.Unmarshal([]byte(fmt.Sprint(settled["content"])), &out); err != nil {
			t.Fatalf("the builder's package binding is not a binding: %v", err)
		}
		return out
	}
	t.Fatal("the builder carries no package binding")
	return nil
}

func TestTheBuildersCarriedPackageBindingTakesThePortFromTheNode(t *testing.T) {
	builder := catalogueManifest(t, "builder")

	// Nothing set: the catalogue's own number, which is what a mesh raised on the defaults uses.
	serves := bindingIn(t, builder, nil)["serves"].(map[string]any)
	if serves["port"] != float64(3000) {
		t.Fatalf("the builder's binding defaults to %v", serves["port"])
	}

	// Given a port, the binding dials it — and the rest of what the forge serves survives, because
	// a setting is merged into the module's own values rather than replacing them.
	moved := bindingIn(t, builder, []Layer{{From: "anchor",
		Values: map[string]any{"serves": map[string]any{"port": float64(3100)}}}})
	got := moved["serves"].(map[string]any)
	if got["port"] != float64(3100) {
		t.Errorf("the builder dials %v, not the port this node gave the package registry", got["port"])
	}
	if got["scheme"] != "http" || got["npm-path"] != "/api/packages/novox/npm/" {
		t.Errorf("setting the port lost the rest of what the forge serves: %v", got)
	}
	if moved["as"] != "mesh-builder" || moved["from"] != "gitea" {
		t.Errorf("setting the port changed who the binding is with: %v", moved)
	}
}

// The two halves are one number. The builder carries a binding because at genesis nothing provides
// `package-registry` to resolve one from; the day the forge is a module, the same consumer is told
// what the forge serves. They have to start from the same port, or a mesh raised on the defaults
// dials one number before the forge is assigned and another after.
func TestTheBuildersCarriedBindingStartsWhereTheForgeServes(t *testing.T) {
	forge := ServedOn(catalogueManifest(t, "gitea"), "package-registry", nil)
	carried := bindingIn(t, catalogueManifest(t, "builder"), nil)["serves"].(map[string]any)
	for _, key := range []string{"port", "scheme", "npm-path"} {
		if fmt.Sprint(forge[key]) != fmt.Sprint(carried[key]) {
			t.Errorf("the forge serves %s %v and the builder's carried binding says %v — the two "+
				"halves of the same registry have drifted apart in the catalogue",
				key, forge[key], carried[key])
		}
	}
}

func TestTheBuildersPackageBindingKeepsItsIdentity(t *testing.T) {
	builder := catalogueManifest(t, "builder")
	// `at` above all: a setting that moves it points the builder, and the registry password it
	// sends as basic auth, at a host somebody else chose.
	for _, key := range []string{"provision", "from", "at", "as"} {
		var refused error
		for _, r := range builder.Resources {
			if fmt.Sprint(r["id"]) != "package-binding" {
				continue
			}
			_, refused = ApplySettings(r, []Layer{{From: "anchor",
				Values: map[string]any{key: "something else"}}})
		}
		if refused == nil {
			t.Errorf("%q can be set on the builder's package binding, which is not a port but who "+
				"the binding is with", key)
		}
	}
}