package usecase

import (
	"context"
	"errors"
	"haixun-backend/internal/library/clock"
	"haixun-backend/internal/model/job/domain/entity"
	"haixun-backend/internal/model/job/domain/enum"
	domrepo "haixun-backend/internal/model/job/domain/repository"
	domusecase "haixun-backend/internal/model/job/domain/usecase"
	"sync"

	"go.mongodb.org/mongo-driver/bson/primitive"
)

type memoryTemplateRepo struct {
	template *entity.Template
}

func (m *memoryTemplateRepo) EnsureIndexes(context.Context) error { return nil }
func (m *memoryTemplateRepo) List(context.Context) ([]*entity.Template, error) {
	if m.template == nil {
		return nil, nil
	}
	return []*entity.Template{m.template}, nil
}
func (m *memoryTemplateRepo) FindByType(context.Context, string) (*entity.Template, error) {
	return m.template, nil
}
func (m *memoryTemplateRepo) Upsert(_ context.Context, template *entity.Template) (*entity.Template, error) {
	m.template = template
	return template, nil
}

type memoryRunRepo struct {
	mu        sync.Mutex
	run       *entity.Run
	succeeded map[string]*entity.Run
}

func newMemoryRunRepo(run *entity.Run) *memoryRunRepo {
	return &memoryRunRepo{run: run, succeeded: map[string]*entity.Run{}}
}

func (m *memoryRunRepo) EnsureIndexes(context.Context) error { return nil }
func (m *memoryRunRepo) Create(ctx context.Context, run *entity.Run) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if run.ID.IsZero() {
		run.ID = primitive.NewObjectID()
	}
	now := clock.NowUnixNano()
	run.CreateAt = now
	run.UpdateAt = now
	m.run = run
	return run, nil
}
func (m *memoryRunRepo) Update(ctx context.Context, run *entity.Run) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	run.UpdateAt = clock.NowUnixNano()
	m.run = run
	if run.Status == enum.RunStatusSucceeded && run.DedupeKey != "" {
		m.succeeded[run.TemplateType+":"+run.DedupeKey] = run
	}
	return run, nil
}
func (m *memoryRunRepo) UpdateIfStatus(ctx context.Context, run *entity.Run, allowed []enum.RunStatus) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run != nil {
		ok := false
		for _, status := range allowed {
			if m.run.Status == status {
				ok = true
				break
			}
		}
		if !ok {
			return nil, errors.New("job state changed; update rejected")
		}
	}
	run.UpdateAt = clock.NowUnixNano()
	m.run = run
	if run.Status == enum.RunStatusSucceeded && run.DedupeKey != "" {
		m.succeeded[run.TemplateType+":"+run.DedupeKey] = run
	}
	return run, nil
}
func (m *memoryRunRepo) UpdateIfLocked(ctx context.Context, run *entity.Run, workerID string, allowed []enum.RunStatus) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run != nil {
		if m.run.LockedBy != "" && m.run.LockedBy != workerID {
			return nil, errors.New("job lock held by another worker")
		}
		ok := false
		for _, status := range allowed {
			if m.run.Status == status {
				ok = true
				break
			}
		}
		if !ok {
			return nil, errors.New("job state changed; update rejected")
		}
	}
	run.UpdateAt = clock.NowUnixNano()
	m.run = run
	if run.Status == enum.RunStatusSucceeded && run.DedupeKey != "" {
		m.succeeded[run.TemplateType+":"+run.DedupeKey] = run
	}
	return run, nil
}
func (m *memoryRunRepo) FindByID(context.Context, string) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	return cloneRun(m.run), nil
}
func (m *memoryRunRepo) List(context.Context, domrepo.RunListFilter, int64, int64) ([]*entity.Run, int64, error) {
	return nil, 0, nil
}
func (m *memoryRunRepo) FindActiveByScope(context.Context, string, string, string) ([]*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run == nil {
		return nil, nil
	}
	switch m.run.Status {
	case enum.RunStatusPending, enum.RunStatusQueued, enum.RunStatusRunning, enum.RunStatusWaitingWorker, enum.RunStatusCancelRequested:
		return []*entity.Run{m.run}, nil
	default:
		return nil, nil
	}
}
func (m *memoryRunRepo) FindSucceededByDedupeKey(_ context.Context, templateType, dedupeKey string) (*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.succeeded[templateType+":"+dedupeKey], nil
}
func (m *memoryRunRepo) FindPendingDue(_ context.Context, now int64, _ int64) ([]*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run == nil || m.run.Status != enum.RunStatusPending || m.run.ScheduledAt == nil {
		return nil, nil
	}
	if *m.run.ScheduledAt <= now {
		return []*entity.Run{m.run}, nil
	}
	return nil, nil
}
func (m *memoryRunRepo) FindCancelRequestedBefore(_ context.Context, before int64, _ int64) ([]*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run == nil || m.run.Status != enum.RunStatusCancelRequested || m.run.CancelRequestedAt == nil {
		return nil, nil
	}
	if *m.run.CancelRequestedAt <= before {
		return []*entity.Run{m.run}, nil
	}
	return nil, nil
}
func (m *memoryRunRepo) FindRunningTimedOut(_ context.Context, now int64, _ int64) ([]*entity.Run, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.run == nil || m.run.LockedUntil == nil {
		return nil, nil
	}
	if m.run.Status != enum.RunStatusRunning && m.run.Status != enum.RunStatusWaitingWorker {
		return nil, nil
	}
	if *m.run.LockedUntil <= now {
		return []*entity.Run{m.run}, nil
	}
	return nil, nil
}

type memoryScheduleRepo struct {
	mu        sync.Mutex
	schedules []*entity.Schedule
}

func (m *memoryScheduleRepo) EnsureIndexes(context.Context) error { return nil }
func (m *memoryScheduleRepo) Create(_ context.Context, schedule *entity.Schedule) (*entity.Schedule, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if schedule.ID.IsZero() {
		schedule.ID = primitive.NewObjectID()
	}
	now := clock.NowUnixNano()
	schedule.CreateAt = now
	schedule.UpdateAt = now
	m.schedules = append(m.schedules, schedule)
	return schedule, nil
}
func (m *memoryScheduleRepo) Update(_ context.Context, schedule *entity.Schedule) (*entity.Schedule, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	schedule.UpdateAt = clock.NowUnixNano()
	for i, item := range m.schedules {
		if item.ID == schedule.ID {
			m.schedules[i] = schedule
			return schedule, nil
		}
	}
	m.schedules = append(m.schedules, schedule)
	return schedule, nil
}
func (m *memoryScheduleRepo) FindByID(_ context.Context, id string) (*entity.Schedule, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	objectID, _ := primitive.ObjectIDFromHex(id)
	for _, item := range m.schedules {
		if item.ID == objectID {
			return item, nil
		}
	}
	return nil, nil
}
func (m *memoryScheduleRepo) List(_ context.Context, _ domrepo.ScheduleListFilter, _, _ int64) ([]*entity.Schedule, int64, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.schedules, int64(len(m.schedules)), nil
}
func (m *memoryScheduleRepo) FindDue(_ context.Context, now int64, _ int64) ([]*entity.Schedule, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	var due []*entity.Schedule
	for _, item := range m.schedules {
		if item.Enabled && item.NextRunAt <= now {
			due = append(due, item)
		}
	}
	return due, nil
}

type memoryEventRepo struct {
	events []*entity.Event
}

func (m *memoryEventRepo) EnsureIndexes(context.Context) error { return nil }
func (m *memoryEventRepo) Append(_ context.Context, event *entity.Event) error {
	m.events = append(m.events, event)
	return nil
}
func (m *memoryEventRepo) ListByJobID(_ context.Context, jobID string, limit int64) ([]*entity.Event, error) {
	if limit <= 0 {
		limit = 50
	}
	var out []*entity.Event
	for _, event := range m.events {
		if event.JobID == jobID {
			out = append(out, event)
		}
	}
	if int64(len(out)) > limit {
		out = out[:limit]
	}
	return out, nil
}

type memoryQueueRepo struct {
	mu            sync.Mutex
	queues        map[string][]string
	cancel        map[string]string
	locks         map[string]string
	dedupe        map[string]string
	schedulerLock string
}

func newMemoryQueueRepo() *memoryQueueRepo {
	return &memoryQueueRepo{
		queues: map[string][]string{},
		cancel: map[string]string{},
		locks:  map[string]string{},
		dedupe: map[string]string{},
	}
}

func (m *memoryQueueRepo) Enqueue(_ context.Context, workerType, jobID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.queues[workerType] = append(m.queues[workerType], jobID)
	return nil
}
func (m *memoryQueueRepo) Dequeue(context.Context, string, int) (string, error) { return "", nil }
func (m *memoryQueueRepo) RemoveJob(_ context.Context, workerType, jobID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	items := m.queues[workerType]
	filtered := make([]string, 0, len(items))
	for _, item := range items {
		if item != jobID {
			filtered = append(filtered, item)
		}
	}
	m.queues[workerType] = filtered
	return nil
}
func (m *memoryQueueRepo) SetCancelSignal(_ context.Context, jobID, reason string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.cancel[jobID] = reason
	return nil
}
func (m *memoryQueueRepo) GetCancelSignal(_ context.Context, jobID string) (bool, string, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	reason, ok := m.cancel[jobID]
	return ok, reason, nil
}
func (m *memoryQueueRepo) ClearCancelSignal(_ context.Context, jobID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	delete(m.cancel, jobID)
	return nil
}
func (m *memoryQueueRepo) TryLock(_ context.Context, jobID, workerID string, _ int) (bool, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if current, ok := m.locks[jobID]; ok && current != workerID {
		return false, nil
	}
	m.locks[jobID] = workerID
	return true, nil
}
func (m *memoryQueueRepo) RefreshLock(_ context.Context, jobID, workerID string, _ int) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if current, ok := m.locks[jobID]; ok && current == workerID {
		return nil
	}
	return errors.New("job lock is not held by worker")
}
func (m *memoryQueueRepo) ReleaseLock(_ context.Context, jobID, workerID string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if current, ok := m.locks[jobID]; ok && current == workerID {
		delete(m.locks, jobID)
	}
	return nil
}
func (m *memoryQueueRepo) TryAcquireDedupe(_ context.Context, templateType, dedupeHash, jobID string, _ int) (bool, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	key := templateType + ":" + dedupeHash
	if _, ok := m.dedupe[key]; ok {
		return false, nil
	}
	m.dedupe[key] = jobID
	return true, nil
}
func (m *memoryQueueRepo) ReleaseDedupe(_ context.Context, templateType, dedupeHash string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	delete(m.dedupe, templateType+":"+dedupeHash)
	return nil
}
func (m *memoryQueueRepo) TrySchedulerLock(_ context.Context, holder string, _ int) (bool, error) {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.schedulerLock != "" && m.schedulerLock != holder {
		return false, nil
	}
	m.schedulerLock = holder
	return true, nil
}
func (m *memoryQueueRepo) ReleaseSchedulerLock(_ context.Context, holder string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.schedulerLock == holder {
		m.schedulerLock = ""
	}
	return nil
}

func (m *memoryQueueRepo) queued(workerType string) []string {
	m.mu.Lock()
	defer m.mu.Unlock()
	return append([]string(nil), m.queues[workerType]...)
}

func testUseCase(template *entity.Template, run *entity.Run) domusecase.UseCase {
	return NewUseCase(
		&memoryTemplateRepo{template: template},
		newMemoryRunRepo(run),
		&memoryScheduleRepo{},
		&memoryEventRepo{},
		newMemoryQueueRepo(),
	)
}

func testUseCaseFull(template *entity.Template, runs *memoryRunRepo, schedules *memoryScheduleRepo, queue *memoryQueueRepo) domusecase.UseCase {
	if schedules == nil {
		schedules = &memoryScheduleRepo{}
	}
	if queue == nil {
		queue = newMemoryQueueRepo()
	}
	return NewUseCase(
		&memoryTemplateRepo{template: template},
		runs,
		schedules,
		&memoryEventRepo{},
		queue,
	)
}

func cloneRun(run *entity.Run) *entity.Run {
	if run == nil {
		return nil
	}
	out := *run
	if run.Progress.Steps != nil {
		out.Progress.Steps = append([]entity.StepProgress(nil), run.Progress.Steps...)
	}
	if run.Payload != nil {
		out.Payload = map[string]any{}
		for k, v := range run.Payload {
			out.Payload[k] = v
		}
	}
	if run.Result != nil {
		out.Result = map[string]any{}
		for k, v := range run.Result {
			out.Result[k] = v
		}
	}
	return &out
}