/*
 * Copyright (C) 2017 TypeFox and others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
 */

import { injectable, inject } from "inversify";
import { ResourceResolver, Resource, ResourceProvider, DisposableCollection, Emitter, Event } from "@theia/core";
import URI from "@theia/core/lib/common/uri";
import { FileSystem } from '@theia/filesystem/lib/common';
import { Workspace } from '@theia/languages/lib/browser';
import { CatalogoUri } from "./catalogo-uri";

export class CatalogoResource implements Resource {

    protected readonly originalUri: string;
    protected readonly toDispose = new DisposableCollection();
    protected readonly onDidChangeContentsEmitter = new Emitter<void>();

    constructor(
        public readonly uri: URI,
        protected readonly originalResource: Resource,
        protected readonly workspace: Workspace
    ) {
        this.originalUri = this.originalResource.uri.toString();
        this.toDispose.push(originalResource);
        this.toDispose.push(this.onDidChangeContentsEmitter);
        if (originalResource.onDidChangeContents) {
            this.toDispose.push(originalResource.onDidChangeContents(() => this.fireDidChangeContents()));
        }
        this.toDispose.push(this.workspace.onDidOpenTextDocument(({ uri }) => this.fireDidChangeContents(uri)));
        this.toDispose.push(this.workspace.onDidChangeTextDocument(({ textDocument }) => this.fireDidChangeContents(textDocument.uri)));
        this.toDispose.push(this.workspace.onDidCloseTextDocument(({ uri }) => this.fireDidChangeContents(uri)));
    }

    dispose(): void {
        this.toDispose.dispose();
    }

    get onDidChangeContents(): Event<void> {
        return this.onDidChangeContentsEmitter.event;
    }
    protected fireDidChangeContents(affectedUri?: string): void {
        if (this.shouldFireDidChangeContents(affectedUri)) {
            this.onDidChangeContentsEmitter.fire(undefined);
        }
    }
    protected shouldFireDidChangeContents(affectedUri?: string): boolean {
        return !affectedUri || affectedUri === this.originalUri;
    }

    async readContents(options?: { encoding?: string | undefined; }): Promise<string> {
        const document = this.workspace.textDocuments.find(document => document.uri === this.originalUri);
        if (document) {
            return this.render(document.getText());
        }
        return this.render(await this.originalResource.readContents(options));
    }

    protected render(text: string): string {
        return text
    }

}

@injectable()
export class CatalogoResourceResolver implements ResourceResolver {

    @inject(FileSystem)
    protected readonly fileSystem: FileSystem;

    @inject(CatalogoUri)
    protected readonly catalogoUri: CatalogoUri;

    @inject(Workspace)
    protected readonly workspace: Workspace;

    @inject(ResourceProvider)
    protected readonly resourceProvider: ResourceProvider;

    async resolve(uri: URI): Promise<CatalogoResource> {
        const resourceUri = this.catalogoUri.validate(uri);
        const originalResource = await this.resourceProvider(resourceUri);
        return new CatalogoResource(uri, originalResource, this.workspace);
    }

}