package firstview

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

	"git.novox.be/novox/mesh-sdk/go/views"

	"github.com/novox/mesh-tools/node-tools/internal/bus"
)

// owners is the four owners' first-view tools as a test answers them: a state's values at a revision, or nothing while down.
type owners struct {
	mu      sync.Mutex
	down    bool
	state   map[string]map[string]string // tool → key → value
	rev     map[string]uint64
	asked   map[string]int
	deliver func(bus.Envelope) error
	finds   map[string]bool
}

func newOwners() *owners {
	return &owners{state: map[string]map[string]string{"placement": {"anchor": `{"p":1}`}, "seat-holders": {"seat": `{"h":1}`},
		"manifests": {"d1": `{"m":1}`}, "modules": {"web": `{"w":1}`}},
		rev: map[string]uint64{"placement": 4, "seat-holders": 2, "manifests": 7, "modules": 3}, asked: map[string]int{}, finds: map[string]bool{}}
}

func (o *owners) ask(address string, _ any) (json.RawMessage, error) {
	o.mu.Lock()
	defer o.mu.Unlock()
	tool := address[strings.LastIndex(address, ".")+1:]
	o.asked[tool]++
	if o.down {
		return nil, errors.New("503 no responders")
	}
	vals := map[string]json.RawMessage{}
	for k, v := range o.state[tool] {
		vals[k] = json.RawMessage(v)
	}
	return json.Marshal(views.Answer{V: 1, Owner: "o", State: tool, Revision: o.rev[tool], Created: time.Unix(1000, 0).UTC(), Values: vals})
}

func (o *owners) say(t *testing.T, state, key, value string, revision uint64, gap bool) {
	t.Helper()
	ev := views.Event{V: 1, Owner: owner(state), State: state, Key: key, Revision: revision, Created: time.Unix(1000, 0).UTC(), Gap: gap}
	if value != "" {
		ev.Value = json.RawMessage(value)
	}
	raw, _ := json.Marshal(ev)
	if err := o.deliver(bus.Envelope{Key: ev.Owner + ".views." + state, Body: raw}); err != nil {
		t.Fatal(err)
	}
}

func owner(state string) string {
	for _, s := range Specs {
		if s.State == state {
			return s.Owner
		}
	}
	return ""
}

func eventually(t *testing.T, what string, ok func() bool) {
	t.Helper()
	for end := time.Now().Add(3 * time.Second); !ok(); time.Sleep(5 * time.Millisecond) {
		if time.Now().After(end) {
			t.Fatal(what)
		}
	}
}

// issue 1966 TLS-5 (ADR 0615 §2, §4, §5, §6): the runner holds the four states from the owners' first views and their
// events alone; nothing is claimed of a state not yet answered; a gap asks the first view once more; an owner that stays down
// past the bound is a finding, cleared by the answer; the status and the hand ask show them.
func TestTheRunnerHoldsTheFourStatesFromTheOwnersFirstViewsAndTheirEvents(t *testing.T) {
	o := newOwners()
	o.down = true
	var logs []string
	var lmu sync.Mutex
	deps := Deps{Module: "node-tools", Ask: o.ask, Bound: 30 * time.Millisecond, Wait: 10 * time.Millisecond,
		Consume: func(deliver func(bus.Envelope) error) (func(), error) { o.deliver = deliver; return func() {}, nil },
		PutFinding: func(key string, _ json.RawMessage) error {
			o.mu.Lock()
			o.finds[key] = true
			o.mu.Unlock()
			return nil
		},
		DeleteFinding: func(key string) error {
			o.mu.Lock()
			delete(o.finds, key)
			o.mu.Unlock()
			return nil
		}}
	v, stop := StartWith(context.Background(), deps, func(f string, a ...any) { lmu.Lock(); logs = append(logs, f); lmu.Unlock() })
	defer stop()

	// Down: nothing is claimed, and past the bound each unanswered view is a finding.
	if _, err := v.State("mesh-delivery-assigner.placement"); err == nil || !strings.Contains(err.Error(), "not been answered") {
		t.Fatalf("a state its owner has not answered is claimed: %v", err)
	}
	eventually(t, "no finding past the bound", func() bool { o.mu.Lock(); defer o.mu.Unlock(); return len(o.finds) == 4 })

	// Up: answered, the findings are cleared, and the pictures hold the owners' values.
	o.mu.Lock()
	o.down = false
	o.mu.Unlock()
	eventually(t, "not answered", func() bool { _, err := v.State("mesh-delivery-indexer.manifests"); return err == nil })
	eventually(t, "findings not cleared", func() bool { o.mu.Lock(); defer o.mu.Unlock(); return len(o.finds) == 0 })
	if got, _ := v.Entry("mesh-delivery-indexer.modules", "web"); string(got) != `{"w":1}` {
		t.Errorf("the modules picture holds %q", got)
	}
	if got, _ := v.Entry("mesh-delivery-indexer.modules", "none"); got != nil {
		t.Errorf("an absent key is %q", got)
	}

	// Events: the next revision is applied; an old one passed over; a deletion removes; none of it asks again.
	asked := func(tool string) int { o.mu.Lock(); defer o.mu.Unlock(); return o.asked[tool] }
	before := asked("placement")
	o.say(t, "placement", "laptop", `{"p":2}`, 5, false)
	o.say(t, "placement", "laptop", `{"p":0}`, 5, false)
	o.say(t, "placement", "anchor", "", 6, false)
	// (a deleted mark carries no value: Deleted is the encoding's, set below)
	if got, _ := v.Entry("mesh-delivery-assigner.placement", "laptop"); string(got) != `{"p":2}` {
		t.Errorf("the next revision is not applied: %q", got)
	}
	if n := asked("placement"); n != before {
		t.Errorf("an event in order asked the first view again (%d asks, was %d)", n, before)
	}

	// A gap (revision 9 where 7 was next) asks the first view once more, said in the log.
	o.say(t, "placement", "x", `{"p":9}`, 9, false)
	eventually(t, "a gap did not ask the first view again", func() bool { return asked("placement") > before })

	// The status says owner, tool, revision and the asks; the hand ask asks every view again.
	var placement views.Status
	for _, s := range v.Status() {
		if s.State == "placement" {
			placement = s
		}
	}
	if placement.Owner != "mesh-delivery-assigner" || placement.Tool != "placement" || placement.Asks < 2 || placement.Answered.IsZero() {
		t.Errorf("the status of placement is %+v", placement)
	}
	manifests := asked("manifests")
	if errs := v.Again(context.Background(), "doubted"); len(errs) != 0 {
		t.Fatalf("the hand ask failed: %v", errs)
	}
	if asked("manifests") != manifests+1 {
		t.Errorf("the hand ask did not ask the manifests again")
	}
	for _, st := range v.Status() {
		if st.State == "manifests" && st.ByHand != 1 {
			t.Errorf("the hand ask is not counted: %+v", st)
		}
	}
	lmu.Lock()
	defer lmu.Unlock()
	if !strings.Contains(strings.Join(logs, "\n"), "a gap in") {
		t.Errorf("the gap was not said in the log: %v", logs)
	}
}