/**
 * earth-now.co
 * Author:  Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * File:    apps/ingest/test/noaa-co2.test.ts
 * Purpose: NOAA GML co2_mm_mlo parser/fetcher tests — fixture-backed incl. missing month + truncated file, no network
 */

import { readFileSync } from "node:fs";
import { describe, expect, it } from "vitest";
import type { FetchLike } from "../src/fetch-like";
import { NOAA_CO2_URL, fetchNoaaCo2, parseNoaaMonthlyCo2 } from "../src/sources/noaa-co2";

const fixture = (name: string): string =>
  readFileSync(new URL(`./fixtures/${name}`, import.meta.url), "utf8");

describe("parseNoaaMonthlyCo2", () => {
  const sample = fixture("co2_mm_mlo_sample.txt");

  it("parses the sample: 16 data rows, one -9.99 missing month skipped → 15 observations", () => {
    const obs = parseNoaaMonthlyCo2(sample);
    expect(obs).toHaveLength(15);
  });

  it("pins each observation to the 15th of the month UTC with the right value", () => {
    const obs = parseNoaaMonthlyCo2(sample);
    expect(obs[0]).toEqual({ time: "2024-01-15T00:00:00.000Z", value: 422.8 });
    expect(obs[obs.length - 1]).toEqual({ time: "2025-04-15T00:00:00.000Z", value: 429.64 });
  });

  it("skips the missing month (2024-06, average -9.99) without inventing a value", () => {
    const obs = parseNoaaMonthlyCo2(sample);
    expect(obs.some((o) => o.time.startsWith("2024-06"))).toBe(false);
    // May and July around the gap are both present.
    expect(obs.some((o) => o.time.startsWith("2024-05"))).toBe(true);
    expect(obs.some((o) => o.time.startsWith("2024-07"))).toBe(true);
  });

  it("THROWS on the truncated fixture (chosen degraded behavior — never feed partial files downstream)", () => {
    expect(() => parseNoaaMonthlyCo2(fixture("co2_mm_mlo_truncated.txt"))).toThrow(
      /expected 8 columns.*truncated/,
    );
  });

  it("throws when there are no data rows at all", () => {
    expect(() => parseNoaaMonthlyCo2("# only comments\n# nothing else\n")).toThrow(
      /no valid data rows/,
    );
  });

  it("throws on out-of-range year/month", () => {
    const bad = "1800  1  1800.04  350.00  350.00  31  0.4  0.1";
    expect(() => parseNoaaMonthlyCo2(bad)).toThrow(/invalid year/);
    const badMonth = "2024 13  2024.99  420.00  420.00  31  0.4  0.1";
    expect(() => parseNoaaMonthlyCo2(badMonth)).toThrow(/invalid month/);
  });
});

describe("fetchNoaaCo2", () => {
  it("fetches the NOAA URL and parses via an injected fetchImpl (no network)", async () => {
    const seen: string[] = [];
    const fetchImpl: FetchLike = async (url) => {
      seen.push(url);
      return { ok: true, status: 200, text: async () => fixture("co2_mm_mlo_sample.txt") };
    };
    const obs = await fetchNoaaCo2(fetchImpl);
    expect(obs).toHaveLength(15);
    expect(seen).toEqual([NOAA_CO2_URL]);
  });

  it("throws on HTTP errors", async () => {
    const fetchImpl: FetchLike = async () => ({ ok: false, status: 500, text: async () => "" });
    await expect(fetchNoaaCo2(fetchImpl)).rejects.toThrow(/HTTP 500/);
  });
});