package check

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"testing"
	"time"

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

// memTries is the tries state as the tools see it, over a memKV.
type memTries struct{ kv *memKV }

func (m memTries) Keys() ([]string, error) { return m.kv.Keys(context.Background()) }
func (m memTries) Get(key string) (json.RawMessage, error) {
	v, _, _, err := m.kv.Get(context.Background(), key)
	return v, err
}
func (m memTries) Create(key string, value []byte) error {
	_, err := m.kv.Create(context.Background(), key, value)
	return err
}

// writtenTries is a memKV that keeps every running try it was given to write, in order.
type writtenTries struct {
	*memKV
	running []Try
}

func (w *writtenTries) Update(ctx context.Context, key string, value []byte, rev uint64) (uint64, error) {
	if t, err := DecodeTry(value); err == nil && !t.Over() {
		w.running = append(w.running, t)
	}
	return w.memKV.Update(ctx, key, value, rev)
}

var tryTrunks = map[string]string{repoA: trunkA, repoSDK: trunkS, hqRepo: trunkA}

func readTry(t testing.TB, kv *memKV, id string) Try {
	t.Helper()
	raw, _, found, _ := kv.Get(context.Background(), id)
	if !found {
		t.Fatalf("no try %s", id)
	}
	tr, err := DecodeTry(raw)
	if err != nil {
		t.Fatal(err)
	}
	return tr
}

func TestATryIsAskedQueuedOncePerHeadAndAtMostFourAtOnce(t *testing.T) { // ADR 0501 §5
	kv := newMemKV()
	store := memTries{kv}
	at := time.Date(2026, 10, 22, 18, 0, 0, 0, time.UTC)
	id, err := AskTry(store, tryTrunks, TryAsk{Repository: repoA, Head: head1, Trunk: "main"}, at)
	if err != nil || !strings.HasPrefix(id, "try-") {
		t.Fatalf("id %q, %v", id, err)
	}
	tr := readTry(t, kv, id)
	if tr.State != TryQueued || tr.Trunk != trunkA || tr.Branch != "main" || tr.Head != head1 || tr.Repository != repoA {
		t.Errorf("try = %+v, want queued on the trunk's head", tr)
	}
	again, err := AskTry(store, tryTrunks, TryAsk{Repository: repoA, Head: head1, Trunk: "main"}, at.Add(time.Second))
	if err != nil || again != id {
		t.Errorf("a second ask of the same head answered %q, %v, want %q", again, err, id)
	}
	// Issue 1890: tries on a build node (a step of theirs running, or none named yet) and tries waiting for one (queued, or
	// their asks not taken) are bounded apart, MaxTries and MaxTriesWaiting; the refusal names both counts.
	onNode := func(i int) Try {
		return Try{ID: fmt.Sprintf("try-%d", i), Repository: repoA, Head: fmt.Sprintf("%040x", i), Trunk: trunkA, State: TryRunning,
			Steps: []TryStep{{Ask: "a", State: delivery.StepRunning}}}
	}
	waitingFor := func(i int) Try {
		return Try{ID: fmt.Sprintf("try-%d", i), Repository: repoA, Head: fmt.Sprintf("%040x", i), Trunk: trunkA, State: TryRunning,
			Steps: []TryStep{{Ask: "a", State: TryAsked}}}
	}
	for _, c := range []struct {
		what          string
		holding, wait int
		refused       string
	}{
		{"four queued behind the checks, none on a node: a fifth is taken", 0, 4, ""},
		{"four on a node", MaxTries, 0, "now 4 run and 0 wait"},
		{"three on a node, eight waiting", 3, MaxTriesWaiting, "a new try is refused while 4 tries run on a build node or 8 wait for one; now 3 run and 8 wait"},
	} {
		kv := newMemKV()
		for i := range c.holding + c.wait {
			tr := waitingFor(i + 1)
			if i < c.holding {
				tr = onNode(i + 1)
			}
			data, _ := encodeTry(tr)
			_, _ = kv.Create(context.Background(), tr.ID, data)
		}
		_, err := AskTry(memTries{kv}, tryTrunks, TryAsk{Repository: repoSDK, Head: head1}, at.Add(time.Minute))
		if (c.refused == "") != (err == nil) || (err != nil && !strings.Contains(err.Error(), c.refused)) {
			t.Errorf("%s: answered %v, want refused %q", c.what, err, c.refused)
		}
	}
}

func TestATryOfARepositoryWithNoCheckedLevelIsRefused(t *testing.T) { // the agreed error of the try
	store := memTries{newMemKV()}
	for _, repo := range []string{"novox/no-trunk", "novox/mesh-lab"} { // hq is checked since R4g (ADR 0527): see tryTrunks
		_, err := AskTry(store, tryTrunks, TryAsk{Repository: repo, Head: head1, Trunk: "main"}, time.Now())
		if err == nil || err.Error() != "no level of "+repo+" is checked by the checker" {
			t.Errorf("%s: %v", repo, err)
		}
	}
	for _, bad := range []TryAsk{{Repository: repoA, Head: "abc"}, {Repository: repoA, Head: head1, Level: "e2e"},
		{Repository: repoA, Head: head1, Tests: "a b"}, {Repository: "x", Head: head1}, {Repository: repoA, Head: head1, Trunk: "-x"}} {
		if _, err := AskTry(store, tryTrunks, bad, time.Now()); err == nil {
			t.Errorf("%+v was taken", bad)
		}
	}
}

func TestATryIsJudgedAsAPullRequestsHeadAndOwesTheForgeNothing(t *testing.T) { // ADR 0501 §5
	ctx := context.Background()
	kv := newMemKV()
	id, err := AskTry(memTries{kv}, tryTrunks, TryAsk{Repository: repoA, Head: head1, Trunk: trunkA}, time.Now())
	if err != nil {
		t.Fatal(err)
	}
	b := newBench(t)
	written := &writtenTries{memKV: kv}
	tr := &Tryer{Tries: written, Judge: b.ex}
	raw, _, _, _ := kv.Get(ctx, id)
	tr.Put(ctx, id, raw)
	tr.Wait()
	got := readTry(t, kv, id)
	if got.State != TryPass || got.Took == "" || got.Head != head1 || got.Trunk != trunkA || got.Said == "" || got.Levels[delivery.LevelUnit].Run != 2 {
		t.Fatalf("try = %+v", got)
	}
	// Issue 1890: while it runs, the try names its ask as soon as it is put, and then where its step stands; the end
	// keeps each ask's node and state.
	if len(written.running) < 3 || len(written.running[1].Asks) != 1 || written.running[1].Steps[0].State != TryAsked ||
		written.running[2].Steps[0].Node != "shanks" {
		t.Errorf("the running try's writes = %+v, want its ask named while it ran, then its node", written.running)
	}
	if len(got.Steps) != 1 || got.Steps[0].Node != "shanks" || got.Steps[0].State != delivery.StepPassed {
		t.Errorf("the ended try's steps = %+v", got.Steps)
	}
	// The try names the asks it put, so the delivery view counts their steps as a try's (build_usage).
	if len(got.Asks) != 1 {
		t.Errorf("asks = %v, want the one check ask the try put", got.Asks)
	} else if _, err := delivery.AskStepKey("shanks", got.Asks[0]); err != nil {
		t.Errorf("the try names %q, which is no ask id: %v", got.Asks[0], err)
	}
	fetch := b.steps.tool("fetch")
	if len(fetch) != 1 || fetch[0].args["commit"] != head1 || fetch[0].args["base"] != trunkA || fetch[0].args["ref"] != "" {
		t.Errorf("fetch = %+v, want the head merged onto the trunk, with no pull request's ref", fetch)
	}
	if keys, _ := b.prev.Keys(ctx); len(keys) != 0 {
		t.Errorf("a try wrote the previews %v", keys)
	}
	// An ended try is not run again.
	raw, _, _, _ = kv.Get(ctx, id)
	tr.Put(ctx, id, raw)
	tr.Wait()
	if n := len(b.steps.tool("fetch")); n != 1 {
		t.Errorf("an ended try was fetched again: %d fetches", n)
	}
}

func TestATryOfOneLevelAndSomeTestsRunsThemAloneAndKeepsNothing(t *testing.T) {
	ctx := context.Background()
	kv := newMemKV()
	id, err := AskTry(memTries{kv}, tryTrunks, TryAsk{Repository: repoA, Head: head1, Level: delivery.LevelIntegration, Tests: "TestBus|TestStore"}, time.Now())
	if err != nil {
		t.Fatal(err)
	}
	b := newBench(t)
	tr := &Tryer{Tries: kv, Judge: b.ex}
	raw, _, _, _ := kv.Get(ctx, id)
	tr.Put(ctx, id, raw)
	tr.Wait()
	tests := b.steps.tool("test")
	if len(tests) != 1 || tests[0].args["level"] != delivery.LevelIntegration || tests[0].args["run"] != "TestBus|TestStore" {
		t.Fatalf("tests = %+v, want the integration level alone with the run pattern", tests)
	}
	if n := len(b.steps.tool("digest")); n != 0 {
		t.Errorf("%d digests for a try of some tests", n)
	}
	if keys, _ := b.kept.Keys(ctx); len(keys) != 0 {
		t.Errorf("kept %v from a try of some tests", keys)
	}
	if got := readTry(t, kv, id); got.State != TryPass || !strings.Contains(got.Said, "only the tests TestBus|TestStore") {
		t.Errorf("try = %+v", got)
	}
}

func TestAFailingTryNamesWhatFailedAndAStepThatCannotRunIsAnError(t *testing.T) {
	ctx := context.Background()
	kv := newMemKV()
	b := newBench(t)
	b.test = func(c stepCall) (any, error) { return captured[Tested](t, "go-test-failing"), nil }
	id, _ := AskTry(memTries{kv}, tryTrunks, TryAsk{Repository: repoA, Head: head1}, time.Now())
	tr := &Tryer{Tries: kv, Judge: b.ex}
	raw, _, _, _ := kv.Get(ctx, id)
	tr.Put(ctx, id, raw)
	tr.Wait()
	if got := readTry(t, kv, id); got.State != TryFail || len(got.Failed) != 1 || !strings.Contains(got.Failed[0], "TestThreeIsFour") {
		t.Errorf("try = %+v", got)
	}
	// No build node is no error since R4g: the try's ask waits in the check stream until a node pulls it (ADR 0525 §4).
}

func TestATryLeftRunningIsTakenOver(t *testing.T) {
	ctx := context.Background()
	kv := newMemKV()
	id, _ := AskTry(memTries{kv}, tryTrunks, TryAsk{Repository: repoA, Head: head1}, time.Now())
	// Left running by a checker that stopped.
	raw, rev, _, _ := kv.Get(ctx, id)
	cur, _ := DecodeTry(raw)
	cur.State = TryRunning
	data, _ := encodeTry(cur)
	if _, err := kv.Update(ctx, id, data, rev); err != nil {
		t.Fatal(err)
	}
	b := newBench(t)
	tr := &Tryer{Tries: kv, Judge: b.ex}
	tr.Reconsider(ctx)
	tr.Wait()
	if got := readTry(t, kv, id); got.State != TryPass {
		t.Errorf("the try left running = %+v, want taken over and passed", got)
	}
}