package builder

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// **A delivery group's member is checked beside the other members' heads** (novox/hq ADR 0382, issue 867): a
// mesh-host change and a mesh-controller change that need each other. The sibling's repository is read beside the
// check at the sibling's head merged onto its base head, in place of the commit the mesh runs.

// aSiblingWorld is the mesh's two core repositories as the trunk holds them, and a pull request into each that the
// other needs: the controller's adds a lock line the node-engine's own check reads, and builds only with the
// node-engine's new validator word.
type aSiblingWorld struct {
	controller, host         string // repositories
	controllerHead, hostHead string // the pull requests' whole heads
	controllerMain, hostMain string // the trunks' heads
}

func theSiblingWorld(t *testing.T) aSiblingWorld {
	t.Helper()
	var w aSiblingWorld
	// The controller's trunk: a judge saying who it is, its lock without the new line, and the check that judges it.
	controllerFiles := aJudgeOf("the trunk's controller")
	controllerFiles["lock.txt"] = "foundation: old\n"
	controllerFiles["module.json"] = `{"module":"mesh-controller"}`
	controllerFiles[CheckScript] = "true\n"
	var controllerRelease string
	w.controller, w.controllerMain, controllerRelease = aRepositoryWithARelease(t, controllerFiles, map[string]string{"r": "r"})
	_ = controllerRelease
	gitInRepo(t, w.controller, "checkout", "--quiet", "-b", "change", "main")
	change := aJudgeOf("the sibling controller")
	change["lock.txt"] = "foundation: new\n"
	w.controllerHead = commitFiles(t, w.controller, change)
	gitInRepo(t, w.controller, "checkout", "--quiet", "main")
	// The node-engine's trunk: a validator, and the check that reads the controller's lock beside it.
	hostFiles := aHostSaying("the trunk's validator")
	hostFiles["module.json"] = `{"module":"mesh-host"}`
	hostFiles[CheckScript] = "set -e\ngrep -q 'foundation: new' \"$MESH_CHECK_BESIDE/mesh-controller/lock.txt\"\n"
	w.host, w.hostMain, _ = aRepositoryWithARelease(t, hostFiles, map[string]string{"r": "r"})
	gitInRepo(t, w.host, "checkout", "--quiet", "-b", "change", "main")
	w.hostHead = commitFiles(t, w.host, aHostSaying("the sibling's validator"))
	gitInRepo(t, w.host, "checkout", "--quiet", "main")
	return w
}

func (w aSiblingWorld) beside() map[string]Beside {
	return map[string]Beside{"mesh-controller": {Repository: w.controller, Ref: w.controllerMain},
		"mesh-host": {Repository: w.host, Ref: w.hostMain}}
}

// hostCheck is the node-engine's pull request checked, with or without its sibling.
func (w aSiblingWorld) hostCheck(t *testing.T, id, workspace, cache string, siblings ...Sibling) CheckVerdict {
	t.Helper()
	if workspace == "" {
		workspace = t.TempDir()
	}
	beside := w.beside()
	delete(beside, "mesh-host")
	v, err := Check(t.Context(), Command, CheckSpec{ID: id, Repository: w.host, Ref: w.hostHead, Owner: "novox",
		Repo: "mesh-host", Number: 114, Base: "main", Judge: "validator", JudgeCache: cache,
		Paths: []string{"validate/v.go"}, Modules: []string{"mesh-host"}, Beside: beside, Siblings: siblings,
		Toolchain: "golang"}, workspace, aFactsRegistry(t), GitCredential{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	return v
}

// controllerCheck is the controller's pull request checked, with or without its sibling.
func (w aSiblingWorld) controllerCheck(t *testing.T, id, cache string, siblings ...Sibling) CheckVerdict {
	t.Helper()
	beside := w.beside()
	delete(beside, "mesh-controller")
	v, err := Check(t.Context(), Command, CheckSpec{ID: id, Repository: w.controller, Ref: w.controllerHead, Owner: "novox",
		Repo: "mesh-controller", Number: 346, Base: "main", Judge: "self", JudgeCache: cache,
		Paths: []string{"lock.txt"}, Modules: []string{"mesh-controller"}, Beside: beside, Siblings: siblings,
		Toolchain: "golang"}, t.TempDir(), aFactsRegistry(t), GitCredential{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	return v
}

func (w aSiblingWorld) controllerSibling() Sibling {
	return Sibling{Repository: "novox/mesh-controller", Number: 346, Head: w.controllerHead, Base: "main", Dir: "mesh-controller"}
}

func (w aSiblingWorld) hostSibling() Sibling {
	return Sibling{Repository: "novox/mesh-host", Number: 114, Head: w.hostHead, Base: "main", Dir: "mesh-host"}
}

// The node-engine's change fails its own check without its sibling (the controller's lock beside it is the trunk's),
// and passes with it read at its merge: the check reads the lock the sibling's change brings, the judge is the
// controller built from the sibling's merge with the node-engine change's own validator, and the verdict names both.
func TestAHostMemberIsCheckedBesideItsControllerSibling(t *testing.T) {
	aRuntimeThatBuildsTheJudge(t)
	w := theSiblingWorld(t)

	alone := w.hostCheck(t, "check-867-host-alone", "", "")
	if alone.Repo == nil || alone.Repo.Verdict != "fail" || len(alone.Siblings) != 0 {
		t.Fatalf("with no sibling the node-engine change should fail its own check (the lock beside it is the trunk's): %+v",
			alone.Repo)
	}

	v := w.hostCheck(t, "check-867-host", "", "", w.controllerSibling())
	if v.Repo == nil || v.Repo.Verdict != "pass" {
		t.Fatalf("beside its sibling the node-engine change should pass its own check: %+v\n%s", v.Repo, v.Report)
	}
	if v.Gate == nil || v.Gate.Verdict != "pass" || !strings.Contains(v.Gate.Summary, "the sibling controller with the sibling's validator") {
		t.Fatalf("the judge was not the controller built from the sibling's merge with the change's own validator: %+v\n%s",
			v.Gate, v.Report)
	}
	baseCommit := w.controllerMain
	if len(v.Siblings) != 1 || v.Siblings[0] != (JudgedSibling{Repository: "novox/mesh-controller", Number: 346,
		Head: w.controllerHead, Base: "main", BaseCommit: baseCommit}) {
		t.Fatalf("the verdict names siblings %+v, not mesh-controller#346 at %s onto %s", v.Siblings, w.controllerHead, baseCommit)
	}
	if v.Beside["mesh-controller"] == baseCommit[:12] || v.Beside["mesh-controller"] == w.controllerHead[:12] {
		t.Fatalf("the controller was read at %s, which is the trunk's or the head and not their merge", v.Beside["mesh-controller"])
	}
	if want := "sibling novox/mesh-controller#346 merge " + v.Beside["mesh-controller"]; v.JudgeFrom != want {
		t.Fatalf("the judge came from %q, not %q", v.JudgeFrom, want)
	}
	if v.Validator != "the change's own validator" {
		t.Fatalf("the validator was %q", v.Validator)
	}
	// The statuses' "beside siblings" part is the forge module's to write, from the verdict's siblings.
	if strings.Contains(v.Gate.Summary, "beside siblings") || strings.Contains(v.Repo.Summary, "beside siblings") {
		t.Fatalf("the check writes the siblings mark itself:\n%s\n%s", v.Gate.Summary, v.Repo.Summary)
	}
	// The base of the sibling is the trunk of the sibling's repository, as the trunk stood when the check cloned it.
	if v.Trunk != w.hostMain[:12] {
		t.Fatalf("the member's own trunk commit is %s, not %s", v.Trunk, w.hostMain[:12])
	}
}

// The controller's change fails with no sibling (it builds only with the node-engine change's validator), and passes with
// it: judged by itself, with the sibling node-engine's validator in place of the one it vendors.
func TestAControllerMemberIsJudgedByItselfWithItsHostSiblingsValidator(t *testing.T) {
	aRuntimeThatBuildsTheJudge(t)
	w := theSiblingWorld(t)
	// The controller change calls a function only the node-engine change brings.
	gitInRepo(t, w.controller, "checkout", "--quiet", "change")
	main := aJudgeOf("the sibling controller")["cmd/mesh-controller/main.go"]
	w.controllerHead = commitFiles(t, w.controller, map[string]string{
		"cmd/mesh-controller/main.go": strings.Replace(main, "validate.Word)", "validate.Word+validate.More)", 1)})
	gitInRepo(t, w.controller, "checkout", "--quiet", "main")
	gitInRepo(t, w.host, "checkout", "--quiet", "change")
	w.hostHead = commitFiles(t, w.host, map[string]string{
		"validate/more.go": "package validate\n\nconst More = \" and more\"\n"})
	gitInRepo(t, w.host, "checkout", "--quiet", "main")

	alone := w.controllerCheck(t, "check-867-controller-alone", "")
	if alone.Gate == nil || alone.Gate.Verdict != "fail" || !strings.Contains(alone.Gate.Summary, "does not build") {
		t.Fatalf("with no sibling the controller change should not build (the validator it vendors lacks More): %+v", alone.Gate)
	}

	v := w.controllerCheck(t, "check-867-controller", "", w.hostSibling())
	if v.Gate == nil || v.Gate.Verdict != "pass" || !strings.Contains(v.Gate.Summary, "the sibling controller with the sibling's validator and more") {
		t.Fatalf("the controller change was not judged by itself with the sibling's validator: %+v\n%s", v.Gate, v.Report)
	}
	if len(v.Siblings) != 1 || v.Siblings[0].Repository != "novox/mesh-host" || v.Siblings[0].BaseCommit != w.hostMain {
		t.Fatalf("the verdict names siblings %+v", v.Siblings)
	}
	if want := "sibling novox/mesh-host#114 merge " + v.Beside["mesh-host"] + "'s validator"; v.Validator != want {
		t.Fatalf("the validator was %q, not %q", v.Validator, want)
	}
	if !strings.HasPrefix(v.JudgeFrom, "this change's own merge ") {
		t.Fatalf("the judge came from %q", v.JudgeFrom)
	}
	// The member's own tree keeps the validator it vendors: its own script reads the vendored files as they are.
	if body := gitInRepo(t, w.controller, "show", "main:vendor/github.com/novox/mesh-host/validate/v.go"); strings.Contains(body, "sibling") {
		t.Fatalf("the trunk's vendored validator was touched: %s", body)
	}
}

// A sibling head that does not merge cleanly onto its base fails the check, naming the sibling and the files.
func TestASiblingThatDoesNotMergeCleanlyFailsTheCheckNamingIt(t *testing.T) {
	aRuntimeThatBuildsTheJudge(t)
	w := theSiblingWorld(t)
	// The base moves under the sibling's head on the same line of the same file.
	gitInRepo(t, w.controller, "checkout", "--quiet", "main")
	commitFiles(t, w.controller, map[string]string{"lock.txt": "foundation: elsewhere\n"})
	v := w.hostCheck(t, "check-867-conflict", "", "", w.controllerSibling())
	if v.Verdict != "fail" || v.Gate == nil || v.Gate.Verdict != "fail" || v.Repo == nil || v.Repo.Verdict != "fail" {
		t.Fatalf("a sibling that does not merge was answered %+v / %+v", v.Gate, v.Repo)
	}
	for _, want := range []string{"novox/mesh-controller#346", "does not merge cleanly", "lock.txt", w.controllerHead[:12]} {
		if !strings.Contains(v.Summary, want) {
			t.Fatalf("the failure does not say %q: %s", want, v.Summary)
		}
	}
	if len(v.Siblings) != 1 || v.Siblings[0].Number != 346 {
		t.Fatalf("the verdict does not name the sibling: %+v", v.Siblings)
	}
}

// A check that could not learn its siblings reads none and says so; one with none to read is judged as before.
func TestACheckThatCouldNotLearnItsSiblingsSaysSo(t *testing.T) {
	aRuntimeThatBuildsTheJudge(t)
	w := theSiblingWorld(t)
	beside := w.beside()
	delete(beside, "mesh-host")
	v, err := Check(t.Context(), Command, CheckSpec{ID: "check-867-unknown", Repository: w.host, Ref: w.hostHead,
		Owner: "novox", Repo: "mesh-host", Number: 114, Base: "main", Judge: "validator", Paths: []string{"validate/v.go"},
		Modules: []string{"mesh-host"}, Beside: beside, SiblingsUnknown: "mesh-delivery did not answer",
		Toolchain: "golang"}, t.TempDir(), aFactsRegistry(t), GitCredential{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	if v.SiblingsUnknown != "mesh-delivery did not answer" || len(v.Siblings) != 0 || v.JudgeFrom != "" {
		t.Fatalf("the verdict says %q, siblings %+v, judge from %q", v.SiblingsUnknown, v.Siblings, v.JudgeFrom)
	}
	if !strings.Contains(v.Gate.Summary, "the trunk's controller with the sibling's validator") {
		t.Fatalf("a check without siblings was not judged as before: %+v", v.Gate)
	}
	if strings.Contains(v.Gate.Summary, "[beside siblings") {
		t.Fatalf("the statuses name siblings that were not read: %s", v.Gate.Summary)
	}
}

// The judge a group made is kept only for the same inputs: the controller's merge and the base commits it was merged
// onto, the validator's source and commit. The same inputs take the judge kept; any other builds it again.
func TestTheGroupsJudgeIsReusedOnlyForTheSameInputs(t *testing.T) {
	built := aRuntimeThatBuildsTheJudge(t)
	w := theSiblingWorld(t)
	cache := t.TempDir()
	w.hostCheck(t, "check-867-cache-1", "", cache, w.controllerSibling())
	if n := builds(t, built); n != 1 {
		t.Fatalf("the first check built %d judge(s)", n)
	}
	v := w.hostCheck(t, "check-867-cache-2", "", cache, w.controllerSibling())
	if n := builds(t, built); n != 1 || v.Gate.Verdict != "pass" {
		t.Fatalf("the same inputs built the judge again (%d builds) or did not pass: %+v", n, v.Gate)
	}
	// The controller sibling's head moves: another merge, another judge.
	gitInRepo(t, w.controller, "checkout", "--quiet", "change")
	w.controllerHead = commitFiles(t, w.controller, map[string]string{"extra.txt": "x"})
	gitInRepo(t, w.controller, "checkout", "--quiet", "main")
	w.hostCheck(t, "check-867-cache-3", "", cache, w.controllerSibling())
	if n := builds(t, built); n != 2 {
		t.Fatalf("a moved sibling head did not build the judge again: %d builds", n)
	}
	// The controller's base moves: the merge differs again.
	commitFiles(t, w.controller, map[string]string{"base.txt": "moved"})
	w.hostCheck(t, "check-867-cache-4", "", cache, w.controllerSibling())
	if n := builds(t, built); n != 3 {
		t.Fatalf("a moved base did not build the judge again: %d builds", n)
	}
	// The validator's source moves: the member's own change differs.
	gitInRepo(t, w.host, "checkout", "--quiet", "change")
	w.hostHead = commitFiles(t, w.host, aHostSaying("another validator"))
	gitInRepo(t, w.host, "checkout", "--quiet", "main")
	w.hostCheck(t, "check-867-cache-5", "", cache, w.controllerSibling())
	if n := builds(t, built); n != 4 {
		t.Fatalf("a moved validator did not build the judge again: %d builds", n)
	}
}

// The contrast the isolation test stands on: built the old way, in the workspace with its HOME and no judge-build
// environment, the same planted Go environment file takes effect in the group's judge build (its toolexec hook runs in
// the judge's sources). Without this, the test below could not fail.
func TestWithThePlainEnvironmentThePlantedWorkspaceReachesTheGroupsJudgeBuild(t *testing.T) {
	aRuntimeThatBuildsTheJudge(t)
	was := judgeBuildEnv
	judgeBuildEnv = func(string, string) []string { return nil }
	t.Cleanup(func() { judgeBuildEnv = was })
	w := theSiblingWorld(t)
	workspace, ran := aPlantedWorkspace(t)
	w.hostCheck(t, "check-867-plain", workspace, "", w.controllerSibling())
	if body, _ := readFile(ran); !strings.Contains(body, "/judge-src") {
		t.Fatalf("with the plain environment the planted hook did not run in the judge's build, so the isolation test proves nothing: %q", body)
	}
}

// **The group's judge is unreviewed code, built where nothing the change's script does can reach it**: a git hook, a
// Go environment file and a Go cache planted in the workspace, and a script writing into its home, change nothing in the
// judge; the judge cache is mounted into judge builds alone.
func TestTheGroupsJudgeIsBuiltWhereNothingTheChangeDoesReachesIt(t *testing.T) {
	built := aRuntimeThatBuildsTheJudge(t)
	homes := filepath.Join(t.TempDir(), "homes")
	t.Setenv("JUDGE_HOMES", homes)
	runs := filepath.Join(t.TempDir(), "runs")
	t.Setenv("RUNS", runs)
	w := theSiblingWorld(t)
	// The member's own script (the base branch's) touches git in its tree and writes into its home.
	gitInRepo(t, w.host, "checkout", "--quiet", "main")
	commitFiles(t, w.host, map[string]string{CheckScript: "set -e\ngit status >/dev/null 2>&1 || true\n" +
		"echo planted > \"$HOME/.gitconfig\"\ngrep -q 'foundation: new' \"$MESH_CHECK_BESIDE/mesh-controller/lock.txt\"\n"})
	w.hostMain = gitInRepo(t, w.host, "rev-parse", "main")
	gitInRepo(t, w.host, "checkout", "--quiet", "change")
	gitInRepo(t, w.host, "rebase", "--quiet", "main")
	w.hostHead = gitInRepo(t, w.host, "rev-parse", "HEAD")
	gitInRepo(t, w.host, "checkout", "--quiet", "main")
	workspace, ran := aPlantedWorkspace(t)
	cache := t.TempDir()
	v := w.hostCheck(t, "check-867-planted", workspace, cache, w.controllerSibling())
	if v.Gate == nil || v.Gate.Verdict != "pass" || v.Repo == nil || v.Repo.Verdict != "pass" {
		t.Fatalf("the check did not pass: %+v %+v\n%s", v.Gate, v.Repo, v.Report)
	}
	if body, _ := readFile(ran); !strings.Contains(body, "/check/mesh-host") {
		t.Fatalf("the planted hook never ran in the member's tree, so this test proves nothing: %q", body)
	}
	if body, _ := readFile(ran); strings.Contains(body, "/judge-src") || judgeRanTheHook(t, ran) != "" {
		t.Fatalf("the hook planted in the workspace ran during the group's judge:\n%s", body)
	}
	if body, _ := readFile(homes); len(body) == 0 || strings.Contains(body, workspace) {
		t.Fatalf("the judge was built with a HOME in the workspace: %q", body)
	}
	said, _ := readFile(built)
	if !strings.Contains(said, "GOCACHE="+filepath.Join(cache, "go-cache")+" GOENV=off go build") {
		t.Fatalf("the judge was not built with the judge cache's Go cache and no Go environment file:\n%s", said)
	}
	// Only a judge build mounts the judge cache.
	body, _ := readFile(runs)
	for _, line := range strings.Split(strings.TrimSpace(body), "\n") {
		if !strings.Contains(line, " go build ") && strings.Contains(line, cache) {
			t.Fatalf("a container the check runs for the pull request names the judge cache: %s", line)
		}
	}
	// The sources the judge was built from are not left where the member's script could have written them.
	if _, err := os.Stat(filepath.Join(workspace, "check", "judge-src")); err == nil {
		t.Fatal("the judge's sources were left in the workspace")
	}
}

func readFile(path string) (string, error) {
	body, err := os.ReadFile(path)
	return string(body), err
}