// 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();
  }
}