package index

import (
	"context"
	"errors"
	"strings"
	"testing"

	"git.novox.be/novox/mesh-sdk/go/delivery"
)

func twoModules(t *testing.T) (*Indexer, *memStore) {
	t.Helper()
	ix, mods := modulesIndexer(t)
	if err := ix.Apply(context.Background(), mergedMsg(catalogueRepo, map[string]string{"modules/a": "t", "modules/b": "t"})); err != nil {
		t.Fatal(err)
	}
	for _, k := range []string{"a", "b"} {
		if _, ok := mods.vals[k]; !ok {
			t.Fatalf("setup: modules.%s not written", k)
		}
	}
	return ix, mods
}

func TestAMergeThatRemovesAModuleDeletesItsKey(t *testing.T) { // 1900/AC1
	ix, mods := twoModules(t)
	if err := ix.Apply(context.Background(), mergedMsg(catalogueRepo, map[string]string{"modules/a": "t2"})); err != nil {
		t.Fatal(err)
	}
	if _, ok := mods.vals["b"]; ok {
		t.Error("modules.b is still held after a merge whose trunk has no module b")
	}
	if _, ok := mods.vals["a"]; !ok {
		t.Error("modules.a, which the trunk still holds, was deleted")
	}
}

func TestAMergeLeavesTheModulesOfAnotherRepository(t *testing.T) { // 1900/AC1 (scope)
	ix, mods := twoModules(t)
	if err := ix.Apply(context.Background(), mergedMsg("novox/mesh-delivery", map[string]string{"modules/c": "t"})); err != nil {
		t.Fatal(err)
	}
	if _, ok := mods.vals["a"]; !ok {
		t.Error("a merge of another repository deleted modules.a")
	}
	if _, ok := mods.vals["b"]; !ok {
		t.Error("a merge of another repository deleted modules.b")
	}
}

func TestAMergeWithoutManifestsDeletesNothing(t *testing.T) { // 1900/AC1: older writers send none, which does not say the trunk is empty
	ix, mods := twoModules(t)
	f := mergedMsg(catalogueRepo, map[string]string{"modules/a": "t2"})
	f.Manifests = nil
	if err := ix.Apply(context.Background(), f); err != nil {
		t.Fatal(err)
	}
	if _, ok := mods.vals["b"]; !ok {
		t.Error("a merge message with no manifests deleted modules.b")
	}
}

func TestAPathWithoutAModuleJSONIsNeverAModule(t *testing.T) { // 1900/AC2: testdata such as fixture-build
	ix, mods := twoModules(t)
	f := mergedMsg(catalogueRepo, map[string]string{"modules/a": "t2"})
	f.Trees["testdata/fixture-build"] = "t" // a directory in the tree whose module.json the message does not carry
	if err := ix.Apply(context.Background(), f); err != nil {
		t.Fatal(err)
	}
	if _, ok := mods.vals["fixture-build"]; ok {
		t.Error("modules.fixture-build written for a path without a module.json")
	}
}

func TestStartingDeletesTheKeysTheTrunkDoesNotHold(t *testing.T) { // 1900/AC3
	ix, mods := twoModules(t)
	ctx := context.Background()
	if err := ix.ApplySource(ctx, 3, sourceOf(catalogueRepo, merge)); err != nil {
		t.Fatal(err)
	}
	var asked string
	ix.Trunk = func(_ context.Context, repository, sha string) ([]string, error) {
		asked = repository + "@" + sha
		return []string{"modules/a"}, nil
	}
	ix.Contains = func(context.Context, string, string, string) (bool, error) { return true, nil }
	if err := ix.Reconcile(ctx); err != nil {
		t.Fatal(err)
	}
	if asked != catalogueRepo+"@"+merge {
		t.Errorf("the trunk was asked as %q, want the source's head of the repository", asked)
	}
	if _, ok := mods.vals["b"]; ok {
		t.Error("modules.b is still held though the trunk holds no module at modules/b")
	}
	if _, ok := mods.vals["a"]; !ok {
		t.Error("modules.a was deleted")
	}
}

func TestStartingDeletesNothingWhenTheTrunkCannotBeRead(t *testing.T) { // 1900/AC3: failure is loud, never a mass delete
	ix, mods := twoModules(t)
	ctx := context.Background()
	if err := ix.ApplySource(ctx, 3, sourceOf(catalogueRepo, merge)); err != nil {
		t.Fatal(err)
	}
	for name, trunk := range map[string]func(context.Context, string, string) ([]string, error){
		"an error":         func(context.Context, string, string) ([]string, error) { return nil, errors.New("forge down") },
		"no module at all": func(context.Context, string, string) ([]string, error) { return nil, nil },
	} {
		ix.Trunk = trunk
		_ = ix.Reconcile(ctx)
		if len(mods.vals) != 2 {
			t.Errorf("%s: %d keys held, want 2 untouched", name, len(mods.vals))
		}
	}
	_ = delivery.RootPath
}

func TestAKeyWrittenAheadOfTheSourceHeadStaysAndOneWithoutAPathIsSkipped(t *testing.T) { // 1900/AC3 (review): the source lags a merge already applied
	ix, mods := twoModules(t) // written at the merge commit C
	ctx := context.Background()
	const older = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
	if err := ix.ApplySource(ctx, 3, sourceOf(catalogueRepo, older)); err != nil {
		t.Fatal(err)
	}
	mods.put("nopath", mustEncode(t, delivery.Module{Repository: catalogueRepo, Commit: older, None2: "x", Manifest: strings.Repeat("a", 64)}))
	ix.Trunk = func(context.Context, string, string) ([]string, error) { return []string{"modules/a"}, nil }
	ix.Contains = func(_ context.Context, _, commit, in string) (bool, error) { return commit == in, nil } // C is not in B
	if err := ix.Reconcile(ctx); err != nil {
		t.Fatal(err)
	}
	for _, k := range []string{"a", "b", "nopath"} {
		if _, ok := mods.vals[k]; !ok {
			t.Errorf("modules.%s was deleted", k)
		}
	}
	ix.Contains = func(context.Context, string, string, string) (bool, error) { return false, errors.New("forge down") }
	_ = ix.Reconcile(ctx)
	if _, ok := mods.vals["b"]; !ok {
		t.Error("modules.b deleted though whether its commit is in the head cannot be read")
	}
}