package operations

import (
	"errors"
	"strings"
	"testing"

	"orchestra/internal/domain"
	"orchestra/internal/store"
)

func mismatch(planRef string) domain.PlanMismatch {
	return domain.PlanMismatch{
		PlanRef: planRef, PhaseID: "phase-1", AtSHA: shaOne,
		Observed:        "a.go already caches per person",
		Contradicts:     "the plan says a.go caches per figure",
		Evidence:        []string{"a.go:88"},
		RequestedAction: domain.PlanMismatchReplan,
	}
}

// A report written against a plan the task no longer works from says nothing
// about the current one. Replaying it would reopen planning over a
// contradiction that may not exist any more.
func TestStalePlanRefIsRefused(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	_, err := RecordPlanMismatch(s, project, id, mismatch("an-older-plan-ref"), shaOne)
	if !errors.Is(err, ErrPlanMismatchStale) {
		t.Fatalf("a stale plan ref was accepted: %v", err)
	}
	assertNoMismatchRecorded(t, s, id)
	assertPhase(t, s, id, domain.WorkPhaseImplement)
}

// A contradiction observed at an older commit may already be fixed.
func TestStaleCommitIsRefused(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	task, _ := s.Task(id)
	_, err := RecordPlanMismatch(s, project, id, mismatch(task.PlanRef), shaTwo)
	if !errors.Is(err, ErrPlanMismatchStale) {
		t.Fatalf("a stale commit was accepted: %v", err)
	}
	assertNoMismatchRecorded(t, s, id)
	assertPhase(t, s, id, domain.WorkPhaseImplement)
}

func TestUnknownPhaseIsRefused(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	task, _ := s.Task(id)
	m := mismatch(task.PlanRef)
	m.PhaseID = "phase-9"
	if _, err := RecordPlanMismatch(s, project, id, m, shaOne); err == nil {
		t.Fatal("a mismatch against a phase the plan does not have was accepted")
	}
	assertNoMismatchRecorded(t, s, id)
}

// The observation is durable before anything moves. A reopen that failed
// partway would otherwise leave a task in an earlier phase with nothing in the
// log explaining why.
func TestMismatchIsRecordedBeforeThePhaseMoves(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	task, _ := s.Task(id)
	if _, err := RecordPlanMismatch(s, project, id, mismatch(task.PlanRef), shaOne); err != nil {
		t.Fatal(err)
	}
	var mismatchSeq, phaseSeq uint64
	for _, e := range s.Events(0) {
		if e.TaskID != id {
			continue
		}
		switch e.Type {
		case domain.EventPlanMismatchRecorded:
			mismatchSeq = e.Seq
		case domain.EventWorkPhaseChanged:
			phaseSeq = e.Seq
		}
	}
	if mismatchSeq == 0 {
		t.Fatal("no mismatch was recorded")
	}
	if phaseSeq < mismatchSeq {
		t.Fatalf("the phase moved at %d before the mismatch was durable at %d", phaseSeq, mismatchSeq)
	}
	assertPhase(t, s, id, domain.WorkPhasePlan)
}

// Recording a mismatch is not the same as superseding the plan. Until a
// replacement is sealed the task still works from the plan it has, with the
// progress it earned.
func TestReplanKeepsTheOldPlanUntilAReplacementIsSealed(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	if _, err := RecordPlanPhaseVerification(s, project, id, "phase-1", shaOne,
		[]VerificationRun{{Command: []string{"go", "build", "./..."}, ExitCode: 0}}); err != nil {
		t.Fatal(err)
	}
	before, _ := s.Task(id)
	if _, err := RecordPlanMismatch(s, project, id, mismatch(before.PlanRef), shaOne); err != nil {
		t.Fatal(err)
	}
	during, _ := s.Task(id)
	if during.PlanRef != before.PlanRef {
		t.Fatal("the plan was superseded by the mismatch alone")
	}
	if _, ok := during.PlanPhase("phase-1"); !ok {
		t.Fatal("progress was discarded before a replacement plan existed")
	}
	if len(during.PlanHistory) != 0 {
		t.Fatalf("the plan was moved to history early: %v", during.PlanHistory)
	}
	// F66: the planning session this reopen convenes has to be told what it is
	// there to fix, and the implementer that found it is gone by then.
	if during.PlanMismatch == nil || during.PlanMismatch.PhaseID != "phase-1" {
		t.Fatalf("the contradiction did not survive to the phase it reopened: %+v", during.PlanMismatch)
	}
}

// Sealing the replacement is the moment the old plan is superseded. Progress
// goes with it, and the old ref stays queryable as provenance.
func TestSealingTheReplacementSupersedesThePlanAndItsProgress(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	if _, err := RecordPlanPhaseVerification(s, project, id, "phase-1", shaOne,
		[]VerificationRun{{Command: []string{"go", "build", "./..."}, ExitCode: 0}}); err != nil {
		t.Fatal(err)
	}
	before, _ := s.Task(id)
	oldRef := before.PlanRef
	if _, err := RecordPlanMismatch(s, project, id, mismatch(oldRef), shaOne); err != nil {
		t.Fatal(err)
	}
	revised := strings.Replace(twoPhasePlan, "# Two phase plan", "# Revised two phase plan", 1)
	if _, err := AdvanceWorkPhase(s, project, id, []byte(revised)); err != nil {
		t.Fatal(err)
	}
	after, _ := s.Task(id)
	if after.PlanRef == oldRef {
		t.Fatal("the replacement did not become the accepted plan")
	}
	if rec, ok := after.PlanPhase("phase-1"); ok {
		t.Fatalf("verification from the superseded plan still counts: %+v", rec)
	}
	if len(after.PlanHistory) != 1 || after.PlanHistory[0] != oldRef {
		t.Fatalf("the superseded plan is not queryable: %v", after.PlanHistory)
	}
	// Provenance: the old verification is still in the log, and the artifact
	// it names is still readable.
	found := false
	for _, e := range s.Events(0) {
		if e.TaskID == id && e.Type == domain.EventPlanPhaseVerified && strings.Contains(string(e.Payload), oldRef) {
			found = true
		}
	}
	if !found {
		t.Fatal("the old verification was erased from the log")
	}
	if _, err := s.Artifact(oldRef); err != nil {
		t.Fatalf("the superseded plan is unreadable: %v", err)
	}
	// The replacement answers the contradiction, so it stops being a live
	// instruction and stays in the log as history.
	if after, _ := s.Task(id); after.PlanMismatch != nil {
		t.Fatalf("a settled contradiction is still live: %+v", after.PlanMismatch)
	}
	assertPhase(t, s, id, domain.WorkPhaseImplement)
}

// research is the other reopen: the plan rests on something the repository
// does not establish, so planning again would repeat the mistake.
func TestResearchActionReopensResearch(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	task, _ := s.Task(id)
	m := mismatch(task.PlanRef)
	m.RequestedAction = domain.PlanMismatchResearch
	if _, err := RecordPlanMismatch(s, project, id, m, shaOne); err != nil {
		t.Fatal(err)
	}
	assertPhase(t, s, id, domain.WorkPhaseResearch)
}

// A contradiction about intent stops for the human instead of reopening.
// Otherwise every ambiguity becomes a replan and the planner outranks the
// person who set the goal.
func TestHumanDecisionBlocksInsteadOfMovingPhases(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	task, _ := s.Task(id)
	m := mismatch(task.PlanRef)
	m.RequestedAction = domain.PlanMismatchHumanDecision
	if _, err := RecordPlanMismatch(s, project, id, m, shaOne); err != nil {
		t.Fatal(err)
	}
	blocked, _ := s.Task(id)
	if blocked.State != domain.StateBlocked || blocked.BlockReason != domain.BlockReasonPlanMismatch {
		t.Fatalf("task = %s / %s, want blocked on plan_mismatch", blocked.State, blocked.BlockReason)
	}
	if blocked.WorkPhase != domain.WorkPhaseImplement {
		t.Fatalf("the phase moved to %q without the human", blocked.WorkPhase)
	}
	for _, want := range []string{"a.go already caches per person", "the plan says a.go caches per figure", "a.go:88"} {
		if !strings.Contains(blocked.Blocker, want) {
			t.Fatalf("the packet omits %q:\n%s", want, blocked.Blocker)
		}
	}
	if PlanMismatchAnswered(s, id) {
		t.Fatal("an unanswered block reported answered")
	}
}

// A human answer can resolve the contradiction without a replan. The plan and
// its progress survive, and the answer outranks the plan wherever they differ.
func TestHumanAnswerResumesTheSamePlanWithoutResealing(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	if _, err := RecordPlanPhaseVerification(s, project, id, "phase-1", shaOne,
		[]VerificationRun{{Command: []string{"go", "build", "./..."}, ExitCode: 0}}); err != nil {
		t.Fatal(err)
	}
	task, _ := s.Task(id)
	planRef := task.PlanRef
	m := mismatch(planRef)
	m.RequestedAction = domain.PlanMismatchHumanDecision
	if _, err := RecordPlanMismatch(s, project, id, m, shaOne); err != nil {
		t.Fatal(err)
	}
	humanReply(t, s, id, "d1", "the per-person cache is correct, keep it and continue phase 2")

	if !PlanMismatchAnswered(s, id) {
		t.Fatal("the human answered and the task is still waiting")
	}
	// F64: asserting the predicate is not asserting the resume. This test
	// passed for as long as the predicate had no caller, while a task blocked
	// on a mismatch stayed blocked forever however the human replied.
	if events, err := ResumeAnsweredBlockers(s); err != nil || len(events) != 1 {
		t.Fatalf("an answered mismatch did not return to the queue: events=%v err=%v", events, err)
	}
	after, _ := s.Task(id)
	if after.State != domain.StateQueued {
		t.Fatalf("state = %s after the human answered, want queued", after.State)
	}
	// F67: the stop is over, so the projection must not keep reporting it.
	if after.BlockReason != "" || after.Blocker != "" {
		t.Fatalf("a resumed task still reports its blocker: %q %q", after.BlockReason, after.Blocker)
	}
	// The answer outranks the plan and stands as an ordinary decision, so the
	// contradiction it settled is not carried into later sessions either.
	if after.PlanMismatch != nil {
		t.Fatalf("an answered contradiction is still live: %+v", after.PlanMismatch)
	}
	if after.PlanRef != planRef {
		t.Fatal("answering the question replaced the plan")
	}
	if _, ok := after.PlanPhase("phase-1"); !ok {
		t.Fatal("answering the question discarded verified progress")
	}
	if len(after.PlanHistory) != 0 {
		t.Fatalf("the plan was superseded by an answer: %v", after.PlanHistory)
	}
	if after.WorkPhase != domain.WorkPhaseImplement {
		t.Fatalf("the phase moved to %q", after.WorkPhase)
	}
	// The answer is standing authority, above the plan.
	intent, err := s.EffectiveIntent(id)
	if err != nil {
		t.Fatal(err)
	}
	if len(intent.Decisions) != 1 {
		t.Fatalf("the answer is not standing authority: %+v", intent.Decisions)
	}
}

// A project whose path omits planning cannot be reopened into it, so the
// contradiction goes to the human rather than stranding the task in a phase it
// has no brief for.
func TestReopenIntoAPhaseTheProjectDoesNotDeclareBlocksInstead(t *testing.T) {
	s, project, id := planWith(t, twoPhasePlan)
	trimmed := project
	trimmed.WorkPhases = []domain.WorkPhase{domain.WorkPhaseFrame, domain.WorkPhaseImplement, domain.WorkPhaseReview}
	task, _ := s.Task(id)
	if _, err := RecordPlanMismatch(s, trimmed, id, mismatch(task.PlanRef), shaOne); err != nil {
		t.Fatal(err)
	}
	blocked, _ := s.Task(id)
	if blocked.BlockReason != domain.BlockReasonPlanMismatch {
		t.Fatalf("block reason = %q", blocked.BlockReason)
	}
	if blocked.WorkPhase != domain.WorkPhaseImplement {
		t.Fatalf("the task was reopened into a phase the project does not declare: %q", blocked.WorkPhase)
	}
}

// The backward edge is Orchestra's alone. An agent asks by reporting a
// mismatch, and phase-request.json still refuses a move back.
func TestAgentCannotAskForABackwardPhaseMove(t *testing.T) {
	if domain.CanTransitionPhase(domain.WorkPhaseImplement, domain.WorkPhasePlan) {
		t.Fatal("the agent-facing phase graph allows implement to plan")
	}
	if domain.CanTransitionPhase(domain.WorkPhaseImplement, domain.WorkPhaseResearch) {
		t.Fatal("the agent-facing phase graph allows implement to research")
	}
	if !domain.CanReopenPhase(domain.WorkPhaseImplement, domain.WorkPhasePlan) {
		t.Fatal("Orchestra cannot reopen planning")
	}
	if domain.CanReopenPhase(domain.WorkPhaseReview, domain.WorkPhasePlan) {
		t.Fatal("review is reopenable into planning, which nothing asked for")
	}
}

// A request may report an observation. It may not carry the next plan: writing
// one is the planning phase's work.
func TestMismatchRequiresAnObservationAndAnAction(t *testing.T) {
	base := mismatch("ref")
	cases := map[string]func(m *domain.PlanMismatch){
		"no observed":    func(m *domain.PlanMismatch) { m.Observed = "" },
		"no contradicts": func(m *domain.PlanMismatch) { m.Contradicts = "" },
		"no phase":       func(m *domain.PlanMismatch) { m.PhaseID = "" },
		"short sha":      func(m *domain.PlanMismatch) { m.AtSHA = "abc" },
		"bad action":     func(m *domain.PlanMismatch) { m.RequestedAction = "rewrite_it_yourself" },
		"no action":      func(m *domain.PlanMismatch) { m.RequestedAction = "" },
		"essay":          func(m *domain.PlanMismatch) { m.Observed = strings.Repeat("x", 1001) },
	}
	for name, mutate := range cases {
		m := base
		mutate(&m)
		if err := m.Validate(); err == nil {
			t.Errorf("%s: accepted, want a refusal", name)
		}
	}
	if err := base.Validate(); err != nil {
		t.Fatalf("a well-formed report was refused: %v", err)
	}
}

func assertPhase(t *testing.T, s *store.Store, id string, want domain.WorkPhase) {
	t.Helper()
	task, _ := s.Task(id)
	if task.WorkPhase != want {
		t.Fatalf("work phase = %q, want %q", task.WorkPhase, want)
	}
}

func assertNoMismatchRecorded(t *testing.T, s *store.Store, id string) {
	t.Helper()
	for _, e := range s.Events(0) {
		if e.TaskID == id && e.Type == domain.EventPlanMismatchRecorded {
			t.Fatal("a refused report was recorded anyway")
		}
	}
}