import { describe, expect, it, vi } from 'vitest';
import type { TextureAsset } from '../../src/core/model/Asset';
import { createEmptyProject } from '../../src/core/model/Project';
import type { TextureStore } from '../../src/core/store/TextureStore';
import { EditorState } from '../../src/editor/state';
import {
  encodeWithinBudget,
  type ImportOutcome,
  importNotice,
  importStoredImage,
  MAX_TEXTURE_SIDE,
  MAX_UPLOAD_BYTES,
  planImageFit,
} from '../../src/editor/textureImport';

/** A blob of exactly `size` bytes – `encodeWithinBudget` only ever looks at the size. */
function blobOf(size: number): Blob {
  return new Blob([new Uint8Array(size)]);
}

function outcome(name: string, error: string | null = null): ImportOutcome {
  return { name, assetId: error ? null : `id-${name}`, error, reused: false };
}

/** A file whose picture the project already had, so no asset was created for it. */
function reused(name: string): ImportOutcome {
  return { name, assetId: `id-${name}`, error: null, reused: true };
}

describe('planImageFit', () => {
  it('leaves an image alone that fits in both senses', () => {
    expect(planImageFit(32, 32, 900)).toEqual({ kind: 'keep' });
    expect(planImageFit(MAX_TEXTURE_SIDE, 1024, MAX_UPLOAD_BYTES)).toEqual({ kind: 'keep' });
  });

  it('caps the longest side and keeps the aspect ratio', () => {
    expect(planImageFit(4000, 3000, 3_000_000)).toEqual({ kind: 'reencode', width: 2048, height: 1536 });
    expect(planImageFit(1000, 4096, 100)).toEqual({ kind: 'reencode', width: 500, height: 2048 });
  });

  it('re-encodes at the original size when only the byte count is over budget', () => {
    expect(planImageFit(800, 600, MAX_UPLOAD_BYTES + 1)).toEqual({
      kind: 'reencode',
      width: 800,
      height: 600,
    });
  });

  it('never scales a picture away to nothing', () => {
    expect(planImageFit(20000, 3, 9_000_000)).toEqual({ kind: 'reencode', width: 2048, height: 1 });
  });
});

describe('encodeWithinBudget', () => {
  it('stops at the first quality that fits', async () => {
    const encode = vi.fn(() => Promise.resolve(blobOf(MAX_UPLOAD_BYTES - 1)));
    const blob = await encodeWithinBudget(encode);
    expect(blob.size).toBe(MAX_UPLOAD_BYTES - 1);
    expect(encode).toHaveBeenCalledTimes(1);
  });

  it('steps the quality down until the result fits', async () => {
    const sizes = [MAX_UPLOAD_BYTES + 1000, MAX_UPLOAD_BYTES - 1000];
    const encode = vi.fn((_quality: number) => Promise.resolve(blobOf(sizes.shift() ?? 0)));
    const blob = await encodeWithinBudget(encode);
    expect(blob.size).toBe(MAX_UPLOAD_BYTES - 1000);
    expect(encode).toHaveBeenCalledTimes(2);
    // Decreasing quality, so a later attempt is never larger than an earlier one.
    const qualities = encode.mock.calls.map(([quality]) => quality);
    expect(qualities).toEqual([...qualities].sort((a, b) => b - a));
  });

  it('returns the last attempt when nothing fits, so the caller can say how far off it was', async () => {
    const encode = vi.fn(() => Promise.resolve(blobOf(MAX_UPLOAD_BYTES + 5)));
    const blob = await encodeWithinBudget(encode);
    expect(blob.size).toBe(MAX_UPLOAD_BYTES + 5);
    expect(encode.mock.calls.length).toBeGreaterThan(1);
  });
});

describe('importNotice', () => {
  it('counts what arrived', () => {
    expect(importNotice([outcome('a.png')])).toBe('Imported 1 image.');
    expect(importNotice([outcome('a.png'), outcome('b.png')])).toBe('Imported 2 images.');
  });

  it('names the first casualty and how many followed', () => {
    expect(importNotice([outcome('a.png', 'too large')])).toBe('Could not import "a.png": too large');
    expect(importNotice([outcome('a.png', 'too large'), outcome('b.png', 'broken')])).toBe(
      'Could not import "a.png": too large (and 1 more)',
    );
  });

  it('reports a partial import as both', () => {
    expect(importNotice([outcome('a.png'), outcome('b.png', 'too large')])).toBe(
      'Imported 1 of 2. Could not import "b.png": too large',
    );
  });

  it('says so when the picture was already in the project', () => {
    // "Imported 1 image" would send the user looking for an asset that was never created.
    expect(importNotice([reused('a.png')])).toBe('That image is already in the project.');
    expect(importNotice([reused('a.png'), reused('b.png')])).toBe(
      'Those 2 images are already in the project.',
    );
    expect(importNotice([outcome('a.png'), reused('b.png')])).toBe(
      'Imported 1 image. One was already in the project.',
    );
    expect(importNotice([outcome('a.png'), reused('b.png'), outcome('c.png', 'broken')])).toBe(
      'Imported 2 of 3. One was already in the project. Could not import "c.png": broken',
    );
  });
});

describe('importStoredImage', () => {
  const FILE = `${'a'.repeat(64)}.png`;
  const image = { file: FILE, width: 64, height: 48, bytes: 900 };
  /** The picker takes the image from the list; nothing here ever uploads. */
  const textures = { upload: vi.fn(), list: vi.fn(), delete: vi.fn() } as unknown as TextureStore;

  function setup(): EditorState {
    const state = new EditorState();
    state.loadProject(createEmptyProject('p', 'P'), 1);
    return state;
  }

  it('makes an asset out of a picture the server already holds', () => {
    const state = setup();
    const outcome = importStoredImage(image, { state, textures });

    const asset = state.project.assets.find((a): a is TextureAsset => a.type === 'texture');
    expect(asset).toMatchObject({ file: FILE, width: 64, height: 48, name: 'Texture' });
    expect(outcome).toMatchObject({ assetId: asset?.id, error: null, reused: false });
    expect(state.selection).toEqual({ kind: 'asset', assetId: asset?.id });
    expect(state.notice).toBe('Added the image to the project.');
    // Adopting is a command like any other, so it can be taken back.
    state.undo();
    expect(state.project.assets.filter((a) => a.type === 'texture')).toEqual([]);
  });

  it('reuses the asset that already names the file instead of making a second one', () => {
    const state = setup();
    const first = importStoredImage(image, { state, textures });
    const again = importStoredImage(image, { state, textures });

    expect(again.assetId).toBe(first.assetId);
    expect(again.reused).toBe(true);
    // Two assets on one file would disagree about `filter`, which is a property of the picture.
    expect(state.project.assets.filter((a) => a.type === 'texture')).toHaveLength(1);
    expect(state.notice).toBe('That image is already in the project.');
  });
});