snengame/internal/coordinator/coordinator.go

package coordinator

import (
	"log"
	"sync"
	"time"

	"github.com/google/uuid"
)

type Coordinator struct {
	Matches         map[uuid.UUID]*Session
	MatchLock       *sync.Mutex
	PlayerQueueChan chan uuid.UUID
	CallbackChan    map[uuid.UUID]chan uuid.UUID
}

func NewCoordinator() *Coordinator {
	return &Coordinator{
		Matches:         make(map[uuid.UUID]*Session),
		MatchLock:       &sync.Mutex{},
		PlayerQueueChan: make(chan uuid.UUID),
		CallbackChan:    make(map[uuid.UUID]chan uuid.UUID),
	}
}

func (c *Coordinator) Start() {
	go MatchMaker(c)
	go MatchCleaner(c)
}

func (c *Coordinator) Coordinate(cmd *SessionCommand) *SessionCommandResult {
	switch cmd.Command {
	case SessionCmdQuery:
		c.CallbackChan[cmd.ID] = make(chan uuid.UUID)
		c.PlayerQueueChan <- cmd.ID
		ticker := time.NewTicker(5 * time.Minute)
		select {
		case m := <-c.CallbackChan[cmd.ID]:
			return &SessionCommandResult{
				ID:      cmd.ID,
				MatchID: m,
				Result:  SessionRespFound,
			}
		case <-ticker.C:
			return &SessionCommandResult{
				ID:      cmd.ID,
				MatchID: uuid.Nil,
				Result:  SessionRespError,
			}
		}
	case SessionCmdJoin:
		m, exists := c.Matches[cmd.MatchID]
		if !exists {
			log.Printf("player %v tried to join non-existent match %v", cmd.ID, cmd.MatchID)
			return &SessionCommandResult{
				ID:      cmd.ID,
				MatchID: uuid.Nil,
				Result:  SessionRespJoinError,
			}
		}
		resp := m.Join(cmd.ID)
		return &SessionCommandResult{
			ID:      cmd.ID,
			MatchID: m.ID,
			Result:  resp,
		}
	case SessionCmdLeave:
		m, exists := c.Matches[cmd.MatchID]
		if !exists || !m.PlayerIn(cmd.ID) {
			return &SessionCommandResult{
				ID:      cmd.ID,
				MatchID: uuid.Nil,
				Result:  SessionRespLeft,
			}
		}
		m.Leave(cmd.ID)
		return &SessionCommandResult{
			ID:      cmd.ID,
			MatchID: uuid.Nil,
			Result:  SessionRespLeft,
		}
	case SessionCmdPlay:
		m, exists := c.Matches[cmd.MatchID]
		if !exists || !m.PlayerIn(cmd.ID) {
			return &SessionCommandResult{
				ID:      cmd.ID,
				MatchID: uuid.Nil,
				Result:  SessionRespLeft,
			}
		}
		resp := m.Play(cmd.ID, cmd.GameCommand)
		return &SessionCommandResult{
			ID:         cmd.ID,
			MatchID:    m.ID,
			Result:     SessionRespPlayed,
			GameResult: resp,
		}
	case SessionCmdPoll:
		m, exists := c.Matches[cmd.MatchID]
		if exists {
			_, exists = m.Broadcasts[cmd.ID]
			if !exists {
				log.Printf("%v has opted in to polling", cmd.ID)
				m.Broadcasts[cmd.ID] = make(chan SessionResp, 10)
			}
			select {
			case res := <-m.Broadcasts[cmd.ID]:
				return &SessionCommandResult{
					ID:      cmd.ID,
					MatchID: m.ID,
					Result:  res,
				}
			default:
				return &SessionCommandResult{
					ID:      cmd.ID,
					MatchID: m.ID,
					Result:  SessionRespBroadcastNone,
				}
			}
		}
	}
	return &SessionCommandResult{
		ID:      cmd.ID,
		MatchID: uuid.Nil,
		Result:  SessionRespError,
	}
}