import type { FolderStatus } from './folder-lifecycle-models.js';
/**
* State machine for managing folder lifecycle transitions.
* Ensures valid state transitions and tracks state history.
*/
export class FolderLifecycleStateMachine {
private currentState: FolderStatus;
private previousState: FolderStatus | null;
// Define valid transitions
private readonly validTransitions: Record<FolderStatus, FolderStatus[]> = {
pending: ['downloading-model', 'scanning', 'error'],
'downloading-model': ['scanning', 'error'],
scanning: ['ready', 'active', 'error'], // Can go to active if no changes
ready: ['indexing', 'error'],
indexing: ['active', 'error'],
active: ['scanning', 'error'],
error: ['pending']
};
constructor(initialState: FolderStatus = 'pending') {
this.currentState = initialState;
this.previousState = null;
}
/**
* Get the current state
*/
getCurrentState(): FolderStatus {
return this.currentState;
}
/**
* Get the previous state
*/
getPreviousState(): FolderStatus | null {
return this.previousState;
}
/**
* Check if a transition to the target state is allowed
*/
canTransitionTo(targetState: FolderStatus): boolean {
this.validateState(targetState);
// Cannot transition to the same state
if (this.currentState === targetState) {
return false;
}
const allowedTransitions = this.validTransitions[this.currentState];
return allowedTransitions.includes(targetState);
}
/**
* Attempt to transition to a new state
* @returns true if transition was successful, false otherwise
*/
transitionTo(targetState: FolderStatus): boolean {
this.validateState(targetState);
if (!this.canTransitionTo(targetState)) {
return false;
}
this.previousState = this.currentState;
this.currentState = targetState;
return true;
}
/**
* Reset the state machine to initial state
*/
reset(): void {
this.currentState = 'pending'; // Fixed: should match constructor default
this.previousState = null;
}
/**
* Validate that a state is valid
*/
private validateState(state: string): asserts state is FolderStatus {
const validStates: FolderStatus[] = ['pending', 'downloading-model', 'scanning', 'ready', 'indexing', 'active', 'error'];
if (!validStates.includes(state as FolderStatus)) {
throw new Error(`Invalid state: ${state}`);
}
}
}
