package knotstream

import (
	"sync"

	"tangled.org/core/knotfeed"
	"tangled.org/core/knotmirror/models"
)

type subscription struct {
	hostname string

	mu      sync.Mutex
	last    knotfeed.Cursor
	applied knotfeed.Cursor

	scheduler *ParallelScheduler
}

func (s *subscription) Last() knotfeed.Cursor {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.last
}

func (s *subscription) Applied() knotfeed.Cursor {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.applied
}

func (s *subscription) Resume(cursor knotfeed.Cursor) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.last, s.applied = cursor, cursor
}

func (s *subscription) Seen(cursor knotfeed.Cursor) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if cursor.Feed() != s.last.Feed() {
		s.applied = knotfeed.NewCursor(cursor.Feed(), 0)
	}
	s.last = cursor
}

func (s *subscription) MarkApplied(cursor knotfeed.Cursor) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if cursor.Feed() == s.applied.Feed() {
		s.applied = knotfeed.NewCursor(s.applied.Feed(), max(s.applied.Seq(), cursor.Seq()))
	}
}

func (s *subscription) HostCursor() models.HostCursor {
	return models.HostCursor{
		Hostname: s.hostname,
		Cursor:   s.Applied(),
	}
}