import { type ItemAction, QueueItemStatus, type StateChangeCallback, type StateTransition } from './types'
/**
* 有効な状態遷移の定義
*/
const VALID_TRANSITIONS: StateTransition[] = [
// 生成フロー
{ from: QueueItemStatus.PENDING, to: QueueItemStatus.GENERATING, action: 'startGeneration' },
{ from: QueueItemStatus.GENERATING, to: QueueItemStatus.READY, action: 'generationComplete' },
{ from: QueueItemStatus.GENERATING, to: QueueItemStatus.ERROR, action: 'generationFailed' },
// 再生フロー
{ from: QueueItemStatus.READY, to: QueueItemStatus.PLAYING, action: 'startPlayback' },
{ from: QueueItemStatus.PLAYING, to: QueueItemStatus.PAUSED, action: 'pause' },
{ from: QueueItemStatus.PAUSED, to: QueueItemStatus.PLAYING, action: 'resume' },
{ from: QueueItemStatus.PLAYING, to: QueueItemStatus.DONE, action: 'playbackComplete' },
{ from: QueueItemStatus.PLAYING, to: QueueItemStatus.ERROR, action: 'playbackFailed' },
// 一時停止からの完了（スキップ時など）
{ from: QueueItemStatus.PAUSED, to: QueueItemStatus.DONE, action: 'playbackComplete' },
]
/**
* アイテム単位の状態マシン
*/
export class ItemStateMachine {
private currentState: QueueItemStatus
private readonly itemId: string
private readonly onStateChange?: StateChangeCallback
constructor(
itemId: string,
initialState: QueueItemStatus = QueueItemStatus.PENDING,
onStateChange?: StateChangeCallback
) {
this.itemId = itemId
this.currentState = initialState
this.onStateChange = onStateChange
}
/**
* 現在の状態を取得
*/
getState(): QueueItemStatus {
return this.currentState
}
/**
* アイテムIDを取得
*/
getId(): string {
return this.itemId
}
/**
* 指定アクションで遷移可能か確認
*/
canTransition(action: ItemAction): boolean {
return VALID_TRANSITIONS.some((t) => t.from === this.currentState && t.action === action)
}
/**
* 状態遷移を実行
* @returns 遷移が成功したかどうか
*/
transition(action: ItemAction): boolean {
const validTransition = VALID_TRANSITIONS.find((t) => t.from === this.currentState && t.action === action)
if (!validTransition) {
console.warn(`Invalid state transition: ${this.currentState} -> ${action} for item ${this.itemId}`)
return false
}
const oldState = this.currentState
this.currentState = validTransition.to
if (this.onStateChange) {
this.onStateChange(this.itemId, oldState, this.currentState)
}
return true
}
/**
* 現在の状態から遷移可能なアクション一覧を取得
*/
getAvailableActions(): ItemAction[] {
return VALID_TRANSITIONS.filter((t) => t.from === this.currentState).map((t) => t.action)
}
/**
* 状態が完了状態（DONE または ERROR）かどうか
*/
isTerminal(): boolean {
return this.currentState === QueueItemStatus.DONE || this.currentState === QueueItemStatus.ERROR
}
/**
* 再生可能な状態かどうか
*/
isPlayable(): boolean {
return this.currentState === QueueItemStatus.READY
}
/**
* 生成中かどうか
*/
isGenerating(): boolean {
return this.currentState === QueueItemStatus.GENERATING
}
/**
* 再生中かどうか
*/
isPlaying(): boolean {
return this.currentState === QueueItemStatus.PLAYING
}
}
