package inventory

import (
	"errors"
	"testing"

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

func manifest(name string, provides, requires []string) catalogue.Manifest {
	return catalogue.Manifest{Module: name, Provides: provides, Requires: requires}
}

func TestAModuleRoundTripsWholeAndUnshredded(t *testing.T) {
	// The manifest is held as it was given. Every field of it is read together when a node is
	// resolved, and a manifest that gains a field should not need a migration before it can be
	// stored — the module system is the thing most likely to grow.
	inv := fresh(t)
	m := catalogue.Manifest{
		Module: "xorg", Provides: []string{"display-server"},
		Capabilities: []string{"seat"},
		Claims:       []catalogue.Claim{{Name: "the-seat", Scope: catalogue.ScopeNode}},
		Resources:    []map[string]any{{"id": "conf", "type": "file", "path": "/etc/X11/x.conf"}},
	}
	if err := inv.RegisterModule(t.Context(), m); err != nil {
		t.Fatal(err)
	}

	shelf, err := inv.Catalogue(t.Context())
	if err != nil {
		t.Fatal(err)
	}
	back, ok := shelf["xorg"]
	if !ok {
		t.Fatal("the module was not in the catalogue")
	}
	if len(back.Claims) != 1 || back.Claims[0].Name != "the-seat" {
		t.Errorf("the claims did not survive: %+v", back.Claims)
	}
	if len(back.Resources) != 1 || back.Resources[0]["path"] != "/etc/X11/x.conf" {
		t.Errorf("the resources did not survive: %+v", back.Resources)
	}
}

func TestRegisteringAgainReplacesTheManifest(t *testing.T) {
	// A manifest changing is the ordinary case — a module gains a requirement, a claim, a
	// resource. What matters is that the change is what the next resolution sees.
	inv := fresh(t)
	if err := inv.RegisterModule(t.Context(), manifest("thing", nil, nil)); err != nil {
		t.Fatal(err)
	}
	if err := inv.RegisterModule(t.Context(), manifest("thing", []string{"a-thing"}, nil)); err != nil {
		t.Fatal(err)
	}

	shelf, err := inv.Catalogue(t.Context())
	if err != nil {
		t.Fatal(err)
	}
	if len(shelf) != 1 {
		t.Fatalf("registering twice made %d modules", len(shelf))
	}
	if len(shelf["thing"].Provides) != 1 {
		t.Error("the second manifest did not replace the first")
	}
}

func TestAModuleAMachineIsRunningCannotBeForgotten(t *testing.T) {
	// Not a fault. It means a machine is running that module now, and removing the record would
	// leave the mesh unable to describe what is on it.
	inv := fresh(t)
	if _, err := inv.AddNode(t.Context(), "laptop"); err != nil {
		t.Fatal(err)
	}
	if err := inv.RegisterModule(t.Context(), manifest("thing", nil, nil)); err != nil {
		t.Fatal(err)
	}
	if err := inv.Assign(t.Context(), "laptop", "thing"); err != nil {
		t.Fatal(err)
	}

	err := inv.ForgetModule(t.Context(), "thing")
	if !errors.Is(err, ErrStillAssigned) {
		t.Fatalf("a module in use was forgotten: %v", err)
	}
	if err := inv.Unassign(t.Context(), "laptop", "thing"); err != nil {
		t.Fatal(err)
	}
	if err := inv.ForgetModule(t.Context(), "thing"); err != nil {
		t.Errorf("an unassigned module could not be forgotten: %v", err)
	}
}

func TestRemovingANodeTakesItsAssignments(t *testing.T) {
	// The asymmetry with modules above, and it is deliberate: a node that is gone cannot be
	// running anything, so its assignments are meaningless rather than dangerous.
	inv := fresh(t)
	node, err := inv.AddNode(t.Context(), "laptop")
	if err != nil {
		t.Fatal(err)
	}
	if err := inv.RegisterModule(t.Context(), manifest("thing", nil, nil)); err != nil {
		t.Fatal(err)
	}
	if err := inv.Assign(t.Context(), "laptop", "thing"); err != nil {
		t.Fatal(err)
	}
	if _, err := inv.store.Pool().Exec(t.Context(), `delete from node where id = $1`, node.ID); err != nil {
		t.Fatal(err)
	}

	var left int
	if err := inv.store.Pool().QueryRow(t.Context(),
		`select count(*) from assignment`).Scan(&left); err != nil {
		t.Fatal(err)
	}
	if left != 0 {
		t.Errorf("%d assignment(s) outlived the node they were on", left)
	}
	// And the module itself survives, because other nodes may be running it.
	shelf, err := inv.Catalogue(t.Context())
	if err != nil {
		t.Fatal(err)
	}
	if len(shelf) != 1 {
		t.Error("removing a node took a module with it")
	}
}

func TestAssigningAModuleTheMeshDoesNotKnowIsRefused(t *testing.T) {
	// Said as "no module of that name" rather than as a foreign key. A person mistyping a module
	// name should be told that, not shown a constraint.
	inv := fresh(t)
	if _, err := inv.AddNode(t.Context(), "laptop"); err != nil {
		t.Fatal(err)
	}
	err := inv.Assign(t.Context(), "laptop", "not-a-module")
	if !errors.Is(err, ErrNoSuchModule) {
		t.Fatalf("assigning an unknown module gave %v", err)
	}
}

func TestAssigningTwiceIsNotAnError(t *testing.T) {
	// It is a statement of what should be true, and it already is.
	inv := fresh(t)
	if _, err := inv.AddNode(t.Context(), "laptop"); err != nil {
		t.Fatal(err)
	}
	if err := inv.RegisterModule(t.Context(), manifest("thing", nil, nil)); err != nil {
		t.Fatal(err)
	}
	for i := 0; i < 3; i++ {
		if err := inv.Assign(t.Context(), "laptop", "thing"); err != nil {
			t.Fatalf("assigning again failed: %v", err)
		}
	}
	assigned, err := inv.Assigned(t.Context(), "laptop")
	if err != nil {
		t.Fatal(err)
	}
	if len(assigned) != 1 {
		t.Errorf("assigned three times and got %v", assigned)
	}
}

func TestANodeThatNeverReportedHasNoCapabilities(t *testing.T) {
	// Not "everything". A node that has never spoken will refuse anything needing a capability,
	// which is wrong but visible — where assuming it can do everything would assign work it
	// cannot do and find out on the machine.
	inv := fresh(t)
	if _, err := inv.AddNode(t.Context(), "laptop"); err != nil {
		t.Fatal(err)
	}
	caps, err := inv.ProfileOf(t.Context(), "laptop")
	if err != nil {
		t.Fatal(err)
	}
	if len(caps) != 0 {
		t.Errorf("a node that never reported has capabilities: %v", caps)
	}
}

func TestOnlyPresentCapabilitiesCount(t *testing.T) {
	// A profile lists what was looked for and whether it was found. A capability that was looked
	// for and absent is the same as one nobody looked for, as far as what may run here goes —
	// and reading the list without the verdict would let a module onto a machine that reported
	// "no".
	inv := fresh(t)
	node, err := inv.AddNode(t.Context(), "laptop")
	if err != nil {
		t.Fatal(err)
	}
	if err := inv.RecordProfile(t.Context(), node.ID, map[string]any{
		"capabilities": []any{
			map[string]any{"name": "seat", "present": true},
			map[string]any{"name": "firewall", "present": false},
		},
	}); err != nil {
		t.Fatal(err)
	}

	caps, err := inv.ProfileOf(t.Context(), "laptop")
	if err != nil {
		t.Fatal(err)
	}
	if !caps["seat"] {
		t.Error("a capability the node reported as present is missing")
	}
	if caps["firewall"] {
		t.Error("a capability the node reported as ABSENT was counted as present")
	}
}