package main

import (
	"reflect"
	"strings"
	"testing"
	"time"

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

// **The planner over edges the store derives**, not edges written by hand: modules registered, builds
// recorded with what they stood on and which repositories they read, the relation answered by
// inventory.Dependencies (dependenciesOf over the records), and the merge planned by reachOfMerge — the
// path a real merge takes, short of the bus.
//
// **The repository rows are CURRENT BEHAVIOUR, documented — not the rule the operator states**
// (novox/hq issue 338, and the decision pending on it): a build that read a repository gives its module a
// packages edge to every module built from that repository, and mergeCandidates moves it on any merge to
// that repository, whatever the files. So a change to C alone, or to a README, moves the module that
// packages C's repository. ADR 0238 §3 records exactly that today ("a repository a recipe names"); the
// expectations marked 338 change with that decision.
func TestASharedRepositoryIsPlannedFromTheRecordsAsItIsToday(t *testing.T) {
	inv := inventory.ForTest(t)
	ctx := t.Context()
	asked := time.Now().Add(-time.Hour)
	register := func(m catalogue.Manifest, repository, path string, against []string, read []inventory.ReadRepository) {
		t.Helper()
		if err := inv.RegisterModule(ctx, m, inventory.Source{Repository: repository, Seat: "git", Path: path,
			Ref: "main", BuiltFrom: "old", Asked: asked}); err != nil {
			t.Fatal(err)
		}
		if err := inv.RecordBuild(ctx, inventory.Build{ID: "build-" + m.Module, Repository: repository, Ref: "main",
			Module: m.Module, Commit: "old", On: "builder", Path: path, Against: against, Read: read, Asked: asked}); err != nil {
			t.Fatal(err)
		}
	}
	controllerRead := []inventory.ReadRepository{{Repository: "novox/mesh-controller", Ref: "main"}}
	agent := catalogue.Manifest{Module: "build-agent", Version: "1",
		Claims: []catalogue.Claim{{Name: "node-build-agent", Scope: catalogue.ScopeNode}}}

	// The shape of issue 338.
	register(catalogue.Manifest{Module: "mesh-controller", Version: "1"}, "novox/mesh-controller", "", nil, nil)
	register(agent, "novox/mesh-catalog", "modules/build-agent", nil, controllerRead)
	register(catalogue.Manifest{Module: "route-proxy", Version: "1"}, "novox/mesh-catalog", "modules/route-proxy", nil, controllerRead)
	register(catalogue.Manifest{Module: "gitea", Version: "1"}, "novox/mesh-catalog", "modules/gitea", nil, nil)
	// A, B and C in one repository; D built against A's artifact, E declaring B, P packaging the repository.
	for _, n := range []string{"a", "b", "c"} {
		register(catalogue.Manifest{Module: n, Version: "1"}, "novox/one", "modules/"+n, nil, nil)
	}
	register(catalogue.Manifest{Module: "d", Version: "1"}, "novox/two", "d",
		[]string{catalogue.ArtifactStoreScheme + "a/runtime@sha256:" + strings.Repeat("0", 64)}, nil)
	register(catalogue.Manifest{Module: "e", Version: "1", Build: &catalogue.Build{
		On: []catalogue.BuildsOn{{Arg: "BASE", Module: "b", Artifact: "runtime"}}}}, "novox/two", "e", nil, nil)
	register(catalogue.Manifest{Module: "p", Version: "1"}, "novox/two", "p", nil,
		[]inventory.ReadRepository{{Repository: "novox/one", Ref: "main"}})

	entries, err := inv.Catalogued(ctx)
	if err != nil {
		t.Fatal(err)
	}
	read, err := inv.ReadRepositories(ctx)
	if err != nil {
		t.Fatal(err)
	}
	edges, err := inv.Dependencies(ctx)
	if err != nil {
		t.Fatal(err)
	}

	// The edges the hand-written rows of TestASharedRepositoryMovesWhatPackagesItAsItDoesToday use are
	// the ones derived here.
	var shared []inventory.Edge
	in338 := map[string]bool{"mesh-controller": true, "build-agent": true, "route-proxy": true, "gitea": true}
	for _, e := range edges {
		if in338[e.From] && in338[e.To] {
			shared = append(shared, e)
		}
	}
	if !reflect.DeepEqual(shared, sharedRepositoryEdges) {
		t.Errorf("derived %v\nthe hand-written rows use %v", shared, sharedRepositoryEdges)
	}
	// Each kind derived from its record: built against (stands-on), build.on (declared), read (packages).
	for _, want := range []inventory.Edge{
		dep("d", inventory.EdgeStandsOn, "a"),
		dep("e", inventory.EdgeDeclared, "b"),
		dep("p", inventory.EdgePackages, "a"),
		dep("p", inventory.EdgePackages, "b"),
		dep("p", inventory.EdgePackages, "c"),
		dep("d", inventory.EdgeBuiltBy, "build-agent"),
	} {
		found := false
		for _, e := range edges {
			found = found || e == want
		}
		if !found {
			t.Errorf("no %s %s %s derived: %v", want.From, want.Kind, want.To, edges)
		}
	}

	for _, c := range []struct {
		what, repo string
		paths      []string
		want       string
		issue338   bool
	}{
		{"A and B changed, C untouched: D after A, E after B; P packages their repository", "one",
			[]string{"modules/a/x.go", "modules/b/x.go"}, "a,b,p | d,e", false},
		{"C alone: C, and P, which packages C's repository", "one",
			[]string{"modules/c/x.go"}, "c,p", true},
		{"a README of the repository P packages: P moves, nothing built from it does", "one",
			[]string{"README.md"}, "p", true},
		{"the dependent's repository: D alone", "two", []string{"d/main.go"}, "d", false},
		{"a README of the controller's repository: all three, three tiers", "mesh-controller",
			[]string{"README.md"}, "mesh-controller | build-agent | route-proxy", true},
		{"the route proxy's directory in the catalogue: it alone", "mesh-catalog",
			[]string{"modules/route-proxy/module.json"}, "route-proxy", false},
		{"the build agent's directory: it alone, nothing it builds", "mesh-catalog",
			[]string{"modules/build-agent/module.json"}, "build-agent", false},
	} {
		_, got := planMerge(t, c.repo, c.paths, entries, read, edges)
		if got != c.want {
			tag := ""
			if c.issue338 {
				tag = " (current behaviour, issue 338)"
			}
			t.Errorf("%s: planned %q, wanted %q%s", c.what, got, c.want, tag)
		}
	}
}