import { is, predicates } from "@sealcode/ts-predicates";
import { ChildProcessWithoutNullStreams, spawn } from "child_process";
import { v4 as uuid } from "uuid";
import containerPool from "./container-pool";
import { q, requests } from "./memory";

let queue_order: ScreenshotRequest[] = [];

export default class ScreenshotRequest {
  public id = uuid();
  public status = "waiting";
  public output = "";
  public images: Record<string, unknown>[] = [];
  public request_time: number = Date.now();
  public started_time: number | null = null;
  public finished_time: number | null = null;
  public processing_took: number | null = null;
  public waiting_took: number | null = null;
  public process: ChildProcessWithoutNullStreams;

  constructor(public url: string, public domains: string[]) {
    q.push(async () => {
      return this.exec();
    });
    requests[this.id] = this;
    queue_order.push(this);
  }

  getJobsAhead(): number {
    if (this.status != "waiting") {
      return 0;
    }
    let count = 0;
    for (const request of queue_order) {
      if (request == this) {
        break;
      }
      count++;
    }
    return count;
  }

  async getJSON(): Promise<{
    url: string;
    domains: string[];
    jobs_ahead: number;
    id: string;
    status: string;
    output: string;
    images: Record<string, unknown>[];
    request_time: number;
    started_time: number | null;
    finished_time: number | null;
    processing_took: number | null;
    waiting_took: number | null;
    elapsed_time_s: number;
  }> {
    return {
      url: this.url,
      domains: this.domains,
      jobs_ahead: this.getJobsAhead(),
      id: this.id,
      status: this.status,
      output: this.output,
      images: this.images,
      request_time: this.request_time,
      started_time: this.started_time,
      finished_time: this.finished_time,
      processing_took: this.processing_took,
      waiting_took: this.waiting_took,
      elapsed_time_s: Math.round(
        ((this.status === "finished" ? this.finished_time || -1 : Date.now()) -
          this.request_time) /
          1000
      ),
    };
  }

  setFinished(): void {
    this.status = "finished";
    this.finished_time = Date.now();
    if (this.started_time) {
      this.processing_took = this.finished_time - this.started_time;
      this.waiting_took = this.started_time - this.request_time;
    }
  }

  async exec(): Promise<void> {
    this.started_time = Date.now();
    this.status = "running";
    const container = containerPool.getContainer();
    await container.waitReady();
    return new Promise((resolve, reject) => {
      this.process = spawn(
        "docker",
        [
          "exec",
          container.id,
          "/opt/run-analysis.sh",
          JSON.stringify({
            url: this.url,
            third_party_domains: this.domains,
          }),
          this.id,
        ],
        { cwd: process.cwd() }
      );
      this.process.on("close", (exitCode) => {
        this.setFinished();
        container.close();
        queue_order = queue_order.filter((request) => request != this);
        if (exitCode === 0) {
          resolve();
        } else {
          reject();
        }
      });
      this.process.stdout.on("data", (d: Buffer) => {
        try {
          const parsed = JSON.parse(d.toString()) as unknown;
          if (
            is(parsed, predicates.object) &&
            is(parsed.new_file, predicates.object)
          ) {
            this.images.push(parsed.new_file);
          }
        } catch (e) {
          //noop
        }
        this.output += d.toString();
        /* console.log("DATA!", d.toString()); */
      });
      this.process.stderr.on("data", (d: Buffer) => {
        this.output += d.toString();
        /* console.log("STDERR!", d.toString()); */
      });
    });
  }
}