package buildstep

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

	nodebuildgo "git.novox.be/novox/mesh-delivery/contracts/go/seats/nodebuildgo"
	sdkstep "git.novox.be/novox/mesh-delivery/sdk/buildstep"
	stdio "git.novox.be/novox/mesh-sdk/go"
)

// 1887/A11: a bundle's source pulls the kind's worker by its seat's name and settles each ask by the runtime's id.
func TestSeatAsksPullsTheKindsWorkerAndSettlesByID(t *testing.T) {
	var pulled []string
	var settled []string
	src := SeatAsks{Language: sdkstep.AskGo,
		Pull: func(worker string, wait time.Duration) (*stdio.Pulled, error) {
			pulled = append(pulled, worker)
			if worker != "SEAT_NODE_BUILD_GO_CHECK_worker" {
				return nil, nil
			}
			return &stdio.Pulled{ID: "p9", Worker: worker, Body: []byte(`{"v":1}`), Delivered: 2}, nil
		},
		Settle: func(id, fate string) error { settled = append(settled, id+" "+fate); return nil }}
	if p, err := src.Next(context.Background(), sdkstep.AskDelivery, 0); err != nil || p != nil {
		t.Fatalf("delivery = %+v, %v", p, err)
	}
	p, err := src.Next(context.Background(), sdkstep.AskCheck, time.Second)
	if err != nil || p == nil || string(p.Data) != `{"v":1}` || p.Delivered != 2 {
		t.Fatalf("check = %+v, %v", p, err)
	}
	_ = p.InProgress()
	_ = p.Ack()
	if len(pulled) != 2 || pulled[0] != "SEAT_NODE_BUILD_GO_DELIVERY_worker" {
		t.Errorf("pulled %v", pulled)
	}
	if len(settled) != 2 || settled[0] != "p9 progress" || settled[1] != "p9 ack" {
		t.Errorf("settled %v", settled)
	}
}

// pauseKV is a pauses state in memory: its put, load, delete and keys.
type pauseKV struct {
	mu sync.Mutex
	m  map[string][]byte
}

func (k *pauseKV) put(key string, v any) (uint64, error) {
	raw, _ := v.(json.RawMessage)
	k.mu.Lock()
	defer k.mu.Unlock()
	if k.m == nil {
		k.m = map[string][]byte{}
	}
	k.m[key] = raw
	return 1, nil
}
func (k *pauseKV) load(key string) ([]byte, error) {
	k.mu.Lock()
	defer k.mu.Unlock()
	return k.m[key], nil
}
func (k *pauseKV) forget(key string) error {
	k.mu.Lock()
	defer k.mu.Unlock()
	delete(k.m, key)
	return nil
}
func (k *pauseKV) keys() ([]string, error) {
	k.mu.Lock()
	defer k.mu.Unlock()
	var out []string
	for key := range k.m {
		out = append(out, key)
	}
	return out, nil
}

// ADR 0664 §5 (issue 1748): the seat's verb drop. An ask dropped before it is given is refused at pull, naming who dropped it
// and why, its key deleted, and never run; one that runs when it is dropped has its step's context cancelled and ends
// refused the same way, acknowledged; the start deletes drops older than DroppedKeep.
func TestADroppedAskIsRefusedAtPullAndARunningOneIsEnded(t *testing.T) {
	for _, running := range []bool{false, true} {
		src, st, kv := NewFakeAsks(), newSteps(), &pauseKV{}
		a := testAsk(sdkstep.AskDelivery)
		started := make(chan struct{})
		ran := false
		var heard func(stdio.StateChange) error
		p := &Puller{Source: src, Language: sdkstep.AskGo, Node: "shanks", Put: st.put, PausePut: kv.put, Load: kv.load, ForgetPause: kv.forget, PauseKeys: kv.keys,
			WatchPauses: func(_ string, h func(stdio.StateChange) error) error { heard = h; return nil },
			Capacity:    func() int { return 1 }, PullWait: 10 * time.Millisecond,
			Run: func(ctx context.Context, _ sdkstep.StepAsk) (any, error) {
				ran = true
				close(started)
				<-ctx.Done()
				return nil, ctx.Err()
			}}
		if !running {
			if err := p.Drop(a.ID, "mesh-delivery-builder", "superseded"); err != nil {
				t.Fatal(err)
			}
		}
		_ = src.PublishAsk(a)
		ctx, cancel := context.WithCancel(context.Background())
		go p.Pull(ctx)
		if running {
			<-started
			// Another node's holder served the verb: its write reaches this node by the watch of the shared pauses state.
			raw, _ := json.Marshal(nodebuildgo.Drop{V: int64(sdkstep.Version), By: "mesh-delivery-builder", Why: "superseded", At: ptr(time.Now())})
			kv.put(sdkstep.DropKey(a.ID), json.RawMessage(raw))
			if err := heard(stdio.StateChange{Key: sdkstep.DropKey(a.ID), Op: "put", Value: raw}); err != nil {
				t.Fatal(err)
			}
		}
		waitFor(t, "the ask ended", func() bool { ack, tm, _ := src.Fates(); return len(ack)+len(tm) == 1 })
		cancel()
		key, _ := sdkstep.AskStepKey("shanks", a.ID)
		s, ok := st.get(key)
		if !ok || s.State != sdkstep.StepDropped || !strings.Contains(s.Reason, "dropped by mesh-delivery-builder: superseded") || ran != running {
			t.Errorf("running %v: step %+v (%v), ran %v", running, s, ok, ran)
		}
		waitFor(t, fmt.Sprint("the drop key deleted, running ", running), func() bool { kv.mu.Lock(); defer kv.mu.Unlock(); _, held := kv.m[sdkstep.DropKey(a.ID)]; return !held })
	}
	// The start deletes a drop older than DroppedKeep and keeps a newer one.
	kv := &pauseKV{}
	old, _ := json.Marshal(nodebuildgo.Drop{V: int64(sdkstep.Version), Why: "old", At: ptr(time.Now().Add(-DroppedKeep - time.Hour))})
	fresh, _ := json.Marshal(nodebuildgo.Drop{V: int64(sdkstep.Version), Why: "fresh", At: ptr(time.Now())})
	kv.put(sdkstep.DropKey("old"), json.RawMessage(old))
	kv.put(sdkstep.DropKey("fresh"), json.RawMessage(fresh))
	// Review 1: a module that sets no watch of the drops says so (a dropped ask running here is then not ended).
	var said []string
	(&Puller{Node: "shanks", Logf: func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }}).watchDrops()
	if len(said) != 1 || !strings.Contains(said[0], "no watch of the drops") {
		t.Errorf("a puller with no watch said %q", said)
	}
	p := &Puller{Load: kv.load, ForgetPause: kv.forget, PauseKeys: kv.keys}
	p.sweepDropped()
	if keys, _ := kv.keys(); len(keys) != 1 || keys[0] != sdkstep.DropKey("fresh") {
		t.Errorf("keys after the sweep = %v, want the fresh drop alone", keys)
	}
}

func ptr[T any](v T) *T { return &v }