import assert from "node:assert/strict";
import { readFileSync } from "node:fs";
import test from "node:test";

import { BIRTH_SKY_FILENAME, saveBirthSkyImage } from "../src/lib/birth-sky/export.ts";
import { waitForHeadingSerif } from "../src/lib/birth-sky/render.ts";

const exportSource = readFileSync(new URL("../src/lib/birth-sky/export.ts", import.meta.url), "utf8");

function environment(share: "ok" | "cancel" | "fail" | "unsupported") {
  const downloads: string[] = [];
  const shared: ShareData[] = [];
  const nav = share === "unsupported"
    ? { canShare: () => false, share: async () => { throw new Error("must not share"); } }
    : {
        canShare: (data: ShareData) => Array.isArray(data.files) && data.files.length === 1,
        share: async (data: ShareData) => {
          shared.push(data);
          if (share === "cancel") throw Object.assign(new Error("dismissed"), { name: "AbortError" });
          if (share === "fail") throw Object.assign(new Error("denied"), { name: "NotAllowedError" });
        },
      };
  return {
    downloads,
    shared,
    env: {
      navigator: nav,
      makeFile: (blob: Blob, name: string) => new File([blob], name, { type: "image/png" }),
      download: (_blob: Blob, name: string) => { downloads.push(name); },
    },
  };
}

const png = new Blob([new Uint8Array([137, 80, 78, 71])], { type: "image/png" });

test("the file name carries no name and no date", () => {
  assert.equal(BIRTH_SKY_FILENAME, "jyotisha-sky.png");
  assert.match(exportSource, /toBlob\([\s\S]*"image\/png"\)/);
});

test("share-capable browsers get the system share sheet with the PNG file", async () => {
  const { env, downloads, shared } = environment("ok");
  assert.equal(await saveBirthSkyImage(png, env), "shared");
  assert.equal(shared.length, 1);
  const file = shared[0]!.files![0]!;
  assert.equal(file.name, "jyotisha-sky.png");
  assert.equal(file.type, "image/png");
  assert.deepEqual(downloads, []);
});

test("without file sharing it downloads through Blob + a.download", async () => {
  const { env, downloads } = environment("unsupported");
  assert.equal(await saveBirthSkyImage(png, env), "downloaded");
  assert.deepEqual(downloads, ["jyotisha-sky.png"]);
  const bare = environment("unsupported");
  assert.equal(await saveBirthSkyImage(png, { ...bare.env, navigator: null }), "downloaded");
  assert.match(exportSource, /anchor\.download = name/);
  assert.match(exportSource, /URL\.revokeObjectURL/);
});

test("a dismissed share sheet is not an error and does not fall back to a download", async () => {
  const { env, downloads } = environment("cancel");
  assert.equal(await saveBirthSkyImage(png, env), "cancelled");
  assert.deepEqual(downloads, []);
  const failing = environment("fail");
  assert.equal(await saveBirthSkyImage(png, failing.env), "downloaded");
  assert.deepEqual(failing.downloads, ["jyotisha-sky.png"]);
});

test("the heading serif wait gives up after its budget instead of hanging", async () => {
  const never = { load: () => new Promise<unknown>(() => {}) };
  const started = Date.now();
  assert.equal(await waitForHeadingSerif("那一刻", never, 30), false);
  assert.ok(Date.now() - started < 1_000);
  assert.equal(await waitForHeadingSerif("那一刻", { load: async () => [{}] }, 30), true);
  assert.equal(await waitForHeadingSerif("那一刻", { load: async () => [] }, 30), false);
  assert.equal(await waitForHeadingSerif("那一刻", { load: async () => { throw new Error("x"); } }, 30), false);
  assert.equal(await waitForHeadingSerif("那一刻", null, 30), false);
});