// Copyright 2019 Drone.IO Inc. All rights reserved.
// Use of this source code is governed by the Drone Non-Commercial License
// that can be found in the LICENSE file.

// +build !oss

package livelog

import (
	"context"
	"errors"
	"sync"

	"github.com/drone/drone/core"
)

// error returned when a stream is not registered with
// the streamer.
var errStreamNotFound = errors.New("stream: not found")

type streamer struct {
	sync.Mutex

	streams map[int64]*stream
}

// New returns a new in-memory log streamer.
func New() core.LogStream {
	return &streamer{
		streams: make(map[int64]*stream),
	}
}

func (s *streamer) Create(ctx context.Context, id int64) error {
	s.Lock()
	s.streams[id] = newStream()
	s.Unlock()
	return nil
}

func (s *streamer) Delete(ctx context.Context, id int64) error {
	s.Lock()
	stream, ok := s.streams[id]
	if ok {
		delete(s.streams, id)
	}
	s.Unlock()
	if !ok {
		return errStreamNotFound
	}
	return stream.close()
}

func (s *streamer) Write(ctx context.Context, id int64, line *core.Line) error {
	s.Lock()
	stream, ok := s.streams[id]
	s.Unlock()
	if !ok {
		return errStreamNotFound
	}
	return stream.write(line)
}

func (s *streamer) Tail(ctx context.Context, id int64) (<-chan *core.Line, <-chan error) {
	s.Lock()
	stream, ok := s.streams[id]
	s.Unlock()
	if !ok {
		return nil, nil
	}
	return stream.subscribe(ctx)
}

func (s *streamer) Info(ctx context.Context) *core.LogStreamInfo {
	s.Lock()
	defer s.Unlock()
	info := &core.LogStreamInfo{
		Streams: map[int64]int{},
	}
	for id, stream := range s.streams {
		stream.Lock()
		info.Streams[id] = len(stream.list)
		stream.Unlock()
	}
	return info
}