// What the side bar shows, kept current from the event stream.

import * as vscode from "vscode";

import type { Agent, Brief, Briefs, Channel, InboxItem, Project } from "./spectra-api";

import { Bridge } from "./bridge";

import { projectForFolder } from "./pure";

export interface StreamEvent {

  seq: number;

  kind: string;

  actor: string;

  subject?: string | null;

}

export class Model implements vscode.Disposable {

  brief: Brief | undefined;

  agents: Agent[] = [];

  channels: Channel[] = [];

  projects: Project[] = [];

  inbox: InboxItem[] = [];

  briefs: Briefs = { overall: null, projects: [] };

  error: string | undefined;

  private readonly changed = new vscode.EventEmitter<void>();

  readonly onDidChange = this.changed.event;

  private readonly events = new vscode.EventEmitter<StreamEvent>();

  /** Every event from the stream, for open chats. */

  readonly onEvent = this.events.event;

  private timer: NodeJS.Timeout | undefined;

  private stream: vscode.Disposable | undefined;

  constructor(private readonly bridge: Bridge) {}

  /** Start following the stream and fetch everything. */

  start(): void {

    this.stream?.dispose();

    this.stream = this.bridge.follow(

      "/api/v1/events?follow=1",

      (data) => {

        try {

          const e = JSON.parse(data) as StreamEvent;

          this.events.fire(e);

        } catch {

          return;

        }

        this.soon();

      },

      () => this.soon(),

    );

    void this.refresh();

  }

  stop(): void {

    this.stream?.dispose();

    this.stream = undefined;

  }

  /** Refresh shortly, once for a burst of events. */

  soon(): void {

    if (this.timer) clearTimeout(this.timer);

    this.timer = setTimeout(() => void this.refresh(), 300);

  }

  async refresh(): Promise<void> {

    try {

      const [brief, agents, channels, projects, inbox, briefs] = await Promise.all([

        this.bridge.request<Brief>("GET", "/api/v1/brief"),

        this.bridge.request<Agent[]>("GET", "/api/v1/agents"),

        this.bridge.request<Channel[]>("GET", "/api/v1/channels"),

        this.bridge.request<Project[]>("GET", "/api/v1/projects"),

        this.bridge.request<InboxItem[]>("GET", "/api/v1/inbox"),

        this.bridge.request<Briefs>("GET", "/api/v1/briefs"),

      ]);

      Object.assign(this, { brief, agents, channels, projects, inbox, briefs, error: undefined });

    } catch (e) {

      this.error = (e as Error).message;

    }

    this.changed.fire();

  }

  /** The project of the first workspace folder, if it is one. */

  folderProject(): string | undefined {

    const f = vscode.workspace.workspaceFolders?.[0];

    return f ? projectForFolder(this.projects, f.uri.fsPath) : undefined;

  }

  dispose(): void {

    this.stop();

    this.changed.dispose();

    this.events.dispose();

  }

}