package service

import (
	"context"
	"errors"
	"testing"

	"sourcecraft.dev/bigbes/sr-ht-spec/core"
)

var fxProject = core.ProjectRef{Owner: "bigbes", Name: "tarantool"}

func metaRef() core.ProjectRef {
	return core.ProjectRef{Owner: "bigbes", Name: core.MetaProjectName}
}

// The meta-project is a value, not a row: resolving it needs no database, which
// is exactly why it needs no sync job either.
func TestEverythingFilterNeedsNoStorage(t *testing.T) {
	svc, _ := newService(t) // its database handle cannot be reached

	f, err := svc.ResolveProject(context.Background(), metaRef())
	if err != nil {
		t.Fatalf("ResolveProject(meta): %v", err)
	}
	if !f.Everything() {
		t.Fatal("the meta-project must exclude nothing")
	}
	// Deliberately unenumerated: a frozen list would omit every space created
	// after the resolve.
	if len(f.Refs()) != 0 || len(f.IDs()) != 0 {
		t.Fatalf("the meta filter enumerated %d spaces; it must not", len(f.Refs()))
	}
	if f.MatchesNothing() {
		t.Fatal("the meta filter matches everything, not nothing")
	}
	if !f.Matches(fxSpace) || !f.MatchesID(1) {
		t.Fatal("the meta filter must match any space")
	}
}

// The trap this type exists to prevent: an empty project is not the corpus.
func TestEmptyFilterIsNotEverything(t *testing.T) {
	empty := core.SpacesFilter(nil, nil)
	if empty.Everything() {
		t.Fatal("a filter over no spaces must not be the meta-project")
	}
	if !empty.MatchesNothing() {
		t.Fatal("a filter with no terms selects nothing")
	}
	if empty.Matches(fxSpace) || empty.MatchesID(1) {
		t.Fatal("a filter with no terms must match no space")
	}

	// And the state that is neither answer: nobody said. It is not silently
	// one of the two — a query refuses it, which is what makes "I forgot to
	// set the scope" a failure instead of a wrong-scoped answer.
	var unset SpaceFilter
	if !unset.IsZero() || unset.Everything() {
		t.Fatal("the zero filter must be neither everything nor a set scope")
	}
}

func TestSpaceFilterMatches(t *testing.T) {
	other := core.SpaceRef{Owner: "bigbes", Name: "notes"}
	f := core.SpacesFilter([]core.SpaceRef{fxSpace}, []int{7})
	if !f.Matches(fxSpace) || !f.MatchesID(7) {
		t.Error("a member space must match")
	}
	if f.Matches(other) || f.MatchesID(8) {
		t.Error("a non-member space must not match")
	}
	if f.MatchesNothing() {
		t.Error("a filter with a term does not match nothing")
	}
}

func TestProjectLifecycle(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	p, err := svc.CreateProject(ctx, fxProject)
	if err != nil {
		t.Fatalf("CreateProject: %v", err)
	}
	if p.ID == 0 {
		t.Error("project has no row id")
	}
	if _, err := svc.CreateProject(ctx, fxProject); !errors.Is(err, ErrProjectExists) {
		t.Errorf("second CreateProject err = %v, want ErrProjectExists", err)
	}

	got, err := svc.GetProject(ctx, fxProject)
	if err != nil {
		t.Fatalf("GetProject: %v", err)
	}
	if got.ID != p.ID || got.Ref != fxProject {
		t.Errorf("GetProject = %+v", got)
	}
	if _, err := svc.GetProject(ctx, core.ProjectRef{Owner: "bigbes", Name: "absent"}); !errors.Is(err, ErrNotFound) {
		t.Errorf("GetProject of a missing project = %v, want ErrNotFound", err)
	}

	projects, err := svc.ListProjects(ctx)
	if err != nil {
		t.Fatalf("ListProjects: %v", err)
	}
	if len(projects) != 1 || projects[0].Ref != fxProject {
		t.Fatalf("projects = %+v", projects)
	}

	if err := svc.DeleteProject(ctx, fxProject); err != nil {
		t.Fatalf("DeleteProject: %v", err)
	}
	if err := svc.DeleteProject(ctx, fxProject); !errors.Is(err, ErrNotFound) {
		t.Errorf("second DeleteProject = %v, want ErrNotFound", err)
	}
}

// The key read: a project is a saved filter over one global index, and this is
// the filter.
func TestResolveProject(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	rfcs, err := svc.CreateSpace(ctx, fxSpace)
	if err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	notes, err := svc.CreateSpace(ctx, core.SpaceRef{Owner: "bigbes", Name: "notes"})
	if err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	if _, err := svc.CreateProject(ctx, fxProject); err != nil {
		t.Fatalf("CreateProject: %v", err)
	}

	// A project with no members selects nothing — never everything.
	f, err := svc.ResolveProject(ctx, fxProject)
	if err != nil {
		t.Fatalf("ResolveProject: %v", err)
	}
	if f.Everything() {
		t.Fatal("an empty project must not resolve to the meta-project")
	}
	if f.IsZero() {
		t.Fatal("a resolved project must carry a scope, not the zero filter")
	}
	if !f.MatchesNothing() {
		t.Fatalf("an empty project resolved to %+v", f)
	}

	if err := svc.AddSpaceToProject(ctx, fxProject, fxSpace); err != nil {
		t.Fatalf("AddSpaceToProject: %v", err)
	}
	// Membership is a set.
	if err := svc.AddSpaceToProject(ctx, fxProject, fxSpace); err != nil {
		t.Fatalf("re-adding a member: %v", err)
	}

	f, err = svc.ResolveProject(ctx, fxProject)
	if err != nil {
		t.Fatalf("ResolveProject: %v", err)
	}
	if len(f.Refs()) != 1 || f.Refs()[0] != fxSpace {
		t.Fatalf("filter refs = %+v", f.Refs())
	}
	if len(f.IDs()) != 1 || f.IDs()[0] != rfcs.ID {
		t.Fatalf("filter ids = %+v, want [%d]", f.IDs(), rfcs.ID)
	}
	if !f.Matches(fxSpace) || !f.MatchesID(rfcs.ID) {
		t.Error("the member space must match")
	}
	if f.Matches(notes.Ref) || f.MatchesID(notes.ID) {
		t.Error("a space outside the project must not match")
	}

	// Membership listing, the counterpart of the filter.
	spaces, err := svc.ProjectSpaces(ctx, fxProject)
	if err != nil {
		t.Fatalf("ProjectSpaces: %v", err)
	}
	if len(spaces) != 1 || spaces[0].Ref != fxSpace {
		t.Fatalf("ProjectSpaces = %+v", spaces)
	}
	if spaces[0].Repo != nil {
		t.Error("ProjectSpaces opened repositories; listing must stay cheap")
	}

	if err := svc.RemoveSpaceFromProject(ctx, fxProject, fxSpace); err != nil {
		t.Fatalf("RemoveSpaceFromProject: %v", err)
	}
	if err := svc.RemoveSpaceFromProject(ctx, fxProject, fxSpace); !errors.Is(err, ErrNotFound) {
		t.Errorf("removing a non-member = %v, want ErrNotFound", err)
	}
	// The space survives its removal from a filter.
	if _, err := svc.OpenSpace(ctx, fxSpace); err != nil {
		t.Errorf("removing a space from a project broke the space: %v", err)
	}

	if _, err := svc.ResolveProject(ctx, core.ProjectRef{Owner: "bigbes", Name: "absent"}); !errors.Is(err, ErrNotFound) {
		t.Errorf("ResolveProject of a missing project = %v, want ErrNotFound", err)
	}
}

// The meta-project unifies what the service owns, with no membership to
// maintain: a space created after it was last looked at is in it already.
func TestMetaProjectListsEverySpaceIncludingNewOnes(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	if _, err := svc.CreateSpace(ctx, fxSpace); err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	spaces, err := svc.ProjectSpaces(ctx, metaRef())
	if err != nil {
		t.Fatalf("ProjectSpaces(meta): %v", err)
	}
	if len(spaces) != 1 {
		t.Fatalf("meta-project lists %d spaces, want 1", len(spaces))
	}

	if _, err := svc.CreateSpace(ctx, core.SpaceRef{Owner: "bigbes", Name: "notes"}); err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	spaces, err = svc.ProjectSpaces(ctx, metaRef())
	if err != nil {
		t.Fatalf("ProjectSpaces(meta): %v", err)
	}
	if len(spaces) != 2 {
		t.Fatalf("meta-project lists %d spaces after a new one was created, want 2", len(spaces))
	}
}

// The meta-project has no row, so every operation on a row refuses it — and the
// one that creates rows refuses to make one that would shadow it.
func TestMetaProjectHasNoRow(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	if _, err := svc.CreateSpace(ctx, fxSpace); err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	if _, err := svc.CreateProject(ctx, metaRef()); !errors.Is(err, core.ErrReservedName) {
		t.Errorf("CreateProject(meta) = %v, want ErrReservedName", err)
	}
	if _, err := svc.GetProject(ctx, metaRef()); !errors.Is(err, ErrNotFound) {
		t.Errorf("GetProject(meta) = %v, want ErrNotFound", err)
	}
	if err := svc.DeleteProject(ctx, metaRef()); !errors.Is(err, ErrNotFound) {
		t.Errorf("DeleteProject(meta) = %v, want ErrNotFound", err)
	}
	if err := svc.AddSpaceToProject(ctx, metaRef(), fxSpace); !errors.Is(err, ErrNotFound) {
		t.Errorf("AddSpaceToProject(meta) = %v, want ErrNotFound", err)
	}
	if err := svc.RemoveSpaceFromProject(ctx, metaRef(), fxSpace); !errors.Is(err, ErrNotFound) {
		t.Errorf("RemoveSpaceFromProject(meta) = %v, want ErrNotFound", err)
	}
	// And it is not in the project list, because the list is of rows.
	projects, err := svc.ListProjects(ctx)
	if err != nil {
		t.Fatalf("ListProjects: %v", err)
	}
	if len(projects) != 0 {
		t.Fatalf("ListProjects = %+v, want none", projects)
	}
}

func TestProjectMembershipRequiresBothSides(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	if _, err := svc.CreateProject(ctx, fxProject); err != nil {
		t.Fatalf("CreateProject: %v", err)
	}
	if err := svc.AddSpaceToProject(ctx, fxProject, fxSpace); !errors.Is(err, ErrNotFound) {
		t.Errorf("adding a space that does not exist = %v, want ErrNotFound", err)
	}
	if _, err := svc.CreateSpace(ctx, fxSpace); err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	missing := core.ProjectRef{Owner: "bigbes", Name: "absent"}
	if err := svc.AddSpaceToProject(ctx, missing, fxSpace); !errors.Is(err, ErrNotFound) {
		t.Errorf("adding to a project that does not exist = %v, want ErrNotFound", err)
	}
}

// A space belongs to any number of projects; a project is a filter, not an
// owner, so nothing about the space changes when one contains it.
func TestProjectsForSpace(t *testing.T) {
	svc, _ := newTestService(t)
	ctx := context.Background()

	if _, err := svc.CreateSpace(ctx, fxSpace); err != nil {
		t.Fatalf("CreateSpace: %v", err)
	}
	projects, err := svc.ProjectsForSpace(ctx, fxSpace)
	if err != nil {
		t.Fatalf("ProjectsForSpace: %v", err)
	}
	if len(projects) != 0 {
		t.Fatalf("a space in no project reports %+v", projects)
	}

	for _, name := range []string{"tarantool", "all-docs"} {
		ref := core.ProjectRef{Owner: "bigbes", Name: name}
		if _, err := svc.CreateProject(ctx, ref); err != nil {
			t.Fatalf("CreateProject %s: %v", ref, err)
		}
		if err := svc.AddSpaceToProject(ctx, ref, fxSpace); err != nil {
			t.Fatalf("AddSpaceToProject %s: %v", ref, err)
		}
	}
	projects, err = svc.ProjectsForSpace(ctx, fxSpace)
	if err != nil {
		t.Fatalf("ProjectsForSpace: %v", err)
	}
	if len(projects) != 2 {
		t.Fatalf("projects = %+v, want 2", projects)
	}
	if projects[0].Ref.Name != "all-docs" || projects[1].Ref.Name != "tarantool" {
		t.Errorf("projects are not ordered by name: %+v", projects)
	}

	if _, err := svc.ProjectsForSpace(ctx, core.SpaceRef{Owner: "bigbes", Name: "absent"}); !errors.Is(err, ErrNotFound) {
		t.Errorf("ProjectsForSpace of a missing space = %v, want ErrNotFound", err)
	}
}