import {AppClass} from '../lifecycle/AppClass'

/**
 * Interface for a class that receives its canonical resolver names upon load.
 */
export interface CanonicalReceiver {
    setCanonicalResolver(fullyQualifiedResolver: string, unqualifiedResolver: string): void
    getCanonicalResolver(): string | undefined
    getFullyQualifiedCanonicalResolver(): string | undefined
}

/**
 * Function that checks whether a given value satisfies the CanonicalReceiver interface.
 * @param something
 */
export function isCanonicalReceiver(something: unknown): something is CanonicalReceiver {
    return (
        typeof something === 'function'
        && typeof (something as any).setCanonicalResolver === 'function'
        && (something as any).setCanonicalResolver.length >= 1
        && typeof (something as any).getCanonicalResolver === 'function'
        && (something as any).getCanonicalResolver.length === 0
    )
}

/**
 * Base class for canonical items that implements the CanonicalReceiver interface.
 * That is, `isCanonicalReceiver(CanonicalItemClass) === true`.
 */
export class CanonicalItemClass extends AppClass {
    /** The type-prefixed canonical resolver of this class, set by the startup unit. */
    private static canonFullyQualifiedResolver?: string

    /** The unqualified canonical resolver of this class, set by the startup unit. */
    private static canonUnqualifiedResolver?: string

    /**
     * Sets the fully- and un-qualified canonical resolver strings. Intended for use
     * by the Canonical unit.
     * @param fullyQualifiedResolver
     * @param unqualifiedResolver
     */
    public static setCanonicalResolver(fullyQualifiedResolver: string, unqualifiedResolver: string): void {
        this.canonFullyQualifiedResolver = fullyQualifiedResolver
        this.canonUnqualifiedResolver = unqualifiedResolver
    }

    /**
     * Get the fully-qualified canonical resolver of this class, if one has been set.
     */
    public static getFullyQualifiedCanonicalResolver(): string | undefined {
        return this.canonFullyQualifiedResolver
    }

    /**
     * Get the unqualified canonical resolver of this class, if one has been set.
     */
    public static getCanonicalResolver(): string | undefined {
        return this.canonUnqualifiedResolver
    }
}