/**
 * A shader's Vertex output (#79): what feeds it runs once per corner of the wearer's grid and moves
 * that corner, in pixels of the picture. Without the node nothing of a shader changes.
 */
import { describe, expect, it } from 'vitest';
import { CreateAssetCommand } from '../../src/core/commands/assetCommands';
import { AddNodeCommand, ConnectCommand } from '../../src/core/commands/graphCommands';
import { findAssetOf } from '../../src/core/model/Project';
import { SHADER_PROPERTY } from '../../src/core/properties/shaders';
import { compileShader, perCornerProblem } from '../../src/core/shader/compile';
import {
  DEFAULT_SUBDIVISIONS,
  MAX_SUBDIVISIONS,
  SHADER_COLOR,
  SHADER_NUMBER,
  SHADER_OUTPUT,
  SHADER_SAMPLE,
  SHADER_TEXTURE_ALPHA,
  SHADER_TEXTURE_COLOR,
  SHADER_TEXTURE_SIZE,
  SHADER_TIME,
  SHADER_UV,
  SHADER_VERTEX_OUTPUT,
  subdivisionsOf,
} from '../../src/core/shader/nodes';
import { paletteEntries } from '../../src/editor/graph/paletteEntries';
import { gridQuad, quadPadding } from '../../src/viewport/quadPadding';
import { makeProject } from '../helpers';

function shader(vertexParams: Record<string, unknown> | null = {}) {
  const f = makeProject();
  const create = new CreateAssetCommand('shader', 'Wave');
  f.stack.execute(create);
  const id = create.asset.id;
  const asset = () => findAssetOf(f.project, id, 'shader')!;
  const add = (type: string, params = {}) => {
    const command = new AddNodeCommand(id, type, 0, 0, params);
    f.stack.execute(command);
    return command.node.id;
  };
  const link = (from: string, fromPort: string, to: string, toPort: string) =>
    f.stack.execute(new ConnectCommand(id, { node: from, port: fromPort }, { node: to, port: toPort }));
  const out = add(SHADER_OUTPUT);
  const corner = vertexParams ? add(SHADER_VERTEX_OUTPUT, vertexParams) : '';
  return { f, asset, add, link, out, corner, build: () => compileShader(asset().graph) };
}

describe('Vertex output (#79)', () => {
  it('leaves a shader without the node exactly as it was', () => {
    const plain = shader(null).build();
    expect(plain.compiled!.vertex).toBeNull();
    // The fragment does not know whether there is a per-corner part.
    expect(shader().build().compiled!.fragment).toBe(plain.compiled!.fragment);
  });

  it('holds every corner in place while nothing feeds it', () => {
    const { compiled } = shader().build();
    expect(compiled!.vertex!.body).toBe('vec2 offset = vec2(0.0, 0.0);');
    expect(compiled!.vertex!.subdivisions).toBe(DEFAULT_SUBDIVISIONS);
  });

  it('moves a corner by what feeds x and y, from the corner’s own UV', () => {
    const s = shader();
    const uv = s.add(SHADER_UV);
    const wave = s.add('ShaderSin');
    const scaled = s.add('ShaderMultiply', { b: 4 });
    s.link(uv, 'v', wave, 'value');
    s.link(wave, 'result', scaled, 'a');
    s.link(scaled, 'result', s.corner, 'x');
    const { vertex } = s.build().compiled!;
    expect(vertex!.body.split('\n')).toEqual([
      'float c0_u = vTextureCoord.x;',
      'float c1_v = vTextureCoord.y;',
      'float c2_result = sin(c1_v);',
      'float c3_result = (c2_result * 4.0);',
      'vec2 offset = vec2(c3_result, 0.0);',
    ]);
  });

  it('emits a node feeding both outputs once for each stage', () => {
    const s = shader();
    const amount = s.add(SHADER_PROPERTY, { name: 'amount', default: 1, min: 0, max: 8 });
    s.link(amount, 'value', s.corner, 'y');
    s.link(amount, 'value', s.out, 'alpha');
    const { compiled } = s.build();
    expect(compiled!.uniforms).toEqual([{ name: 'amount', kind: 'number', default: 1 }]);
    expect(compiled!.fragment).toContain('float n0_value = u_amount;');
    expect(compiled!.vertex!.body).toContain('float c0_value = u_amount;');
    // One precision for a uniform both stages declare: the fragment's default.
    expect(compiled!.vertex!.head).toContain('uniform mediump float u_amount;');
  });

  it('redraws every tick for a Time node only the corners read', () => {
    const s = shader();
    const time = s.add(SHADER_TIME);
    s.link(time, 'value', s.corner, 'x');
    const { compiled } = s.build();
    expect(compiled!.time).toBe(true);
    expect(compiled!.vertex!.head).toContain('uniform mediump float uTime;');
    expect(compiled!.fragment).not.toContain('uTime');
    // And the other way round the vertex stage does not declare what it never reads.
    const other = shader();
    const clock = other.add(SHADER_TIME);
    other.link(clock, 'value', other.out, 'alpha');
    expect(other.build().compiled!.vertex!.head).not.toContain('uTime');
    expect(other.build().compiled!.fragment).toContain('uniform float uTime;');
  });

  it.each([
    [SHADER_TEXTURE_ALPHA, 'value', 'Texture alpha'],
    [SHADER_SAMPLE, 'alpha', 'Sample texture'],
    [SHADER_TEXTURE_SIZE, 'width', 'Texture size'],
  ])('says at the node that %s is not there per corner', (type, port, label) => {
    const s = shader();
    s.link(s.add(type), port, s.corner, 'x');
    const build = s.build();
    expect(build.compiled).toBeNull();
    expect(build.problems).toEqual({ [s.corner]: perCornerProblem(label) });
    expect(build.reason).toBe(perCornerProblem(label));
  });

  it('says so too for a colour arriving through a calculation', () => {
    for (const type of [SHADER_TEXTURE_COLOR, SHADER_COLOR]) {
      const s = shader();
      const luminance = s.add('ShaderLuminance');
      s.link(s.add(type), 'color', luminance, 'color');
      s.link(luminance, 'value', s.corner, 'y');
      expect(s.build().compiled).toBeNull();
      expect(s.build().problems[s.corner]).toMatch(/^Not available per corner: /);
    }
    // An input that would read the picture while unconnected is the same thing.
    const unfed = shader();
    unfed.link(unfed.add('ShaderLuminance'), 'value', unfed.corner, 'y');
    expect(unfed.build().problems).toEqual({ [unfed.corner]: perCornerProblem('the picture') });
  });

  it('still lets the same nodes feed the Output', () => {
    const s = shader();
    s.link(s.add(SHADER_TEXTURE_ALPHA), 'value', s.out, 'alpha');
    s.link(s.add(SHADER_NUMBER, { value: 2 }), 'value', s.corner, 'x');
    const build = s.build();
    expect(build.problems).toEqual({});
    expect(build.compiled!.vertex!.body).toContain('vec2 offset = vec2(c0_value, 0.0);');
  });

  it('reads Subdivisions as whole cells between 1 and the limit', () => {
    expect(subdivisionsOf({})).toBe(DEFAULT_SUBDIVISIONS);
    expect(subdivisionsOf({ subdivisions: 1 })).toBe(1);
    expect(subdivisionsOf({ subdivisions: 0 })).toBe(1);
    expect(subdivisionsOf({ subdivisions: -3 })).toBe(1);
    expect(subdivisionsOf({ subdivisions: 2.6 })).toBe(3);
    expect(subdivisionsOf({ subdivisions: MAX_SUBDIVISIONS + 9 })).toBe(MAX_SUBDIVISIONS);
    expect(subdivisionsOf({ subdivisions: 'fine' })).toBe(DEFAULT_SUBDIVISIONS);
    expect(shader({ subdivisions: 32 }).build().compiled!.vertex!.subdivisions).toBe(32);
  });

  it('is offered once, like the Output', () => {
    const without = shader(null);
    const offered = (s: typeof without) =>
      paletteEntries(s.f.project, s.asset()).filter((e) => e.def.type === SHADER_VERTEX_OUTPUT).length;
    expect(offered(without)).toBe(1);
    expect(offered(shader())).toBe(0);
  });
});

describe('gridQuad', () => {
  it('is the unit quad cut into cells, corners row by row', () => {
    const grid = gridQuad(null, 2);
    expect([...grid.positions]).toEqual([0, 0, 0.5, 0, 1, 0, 0, 0.5, 0.5, 0.5, 1, 0.5, 0, 1, 0.5, 1, 1, 1]);
    expect([...grid.uvs]).toEqual([...grid.positions]);
    expect([...grid.indices.slice(0, 6)]).toEqual([0, 1, 4, 0, 4, 3]);
    expect(grid.indices.length).toBe(2 * 2 * 6);
  });

  it('has as many corners as the cells need, and every index is one of them', () => {
    for (const cells of [1, 8, 64]) {
      const grid = gridQuad(null, cells);
      expect(grid.positions.length).toBe((cells + 1) ** 2 * 2);
      expect(Math.max(...grid.indices)).toBe((cells + 1) ** 2 - 1);
    }
  });

  it('covers the padded rectangle, the picture still at 0..1', () => {
    const grid = gridQuad(quadPadding(4, 16, 32), 4);
    const xs = [...grid.positions].filter((_, i) => i % 2 === 0);
    const ys = [...grid.positions].filter((_, i) => i % 2 === 1);
    expect([Math.min(...xs), Math.max(...xs)]).toEqual([-0.25, 1.25]);
    expect([Math.min(...ys), Math.max(...ys)]).toEqual([-0.125, 1.125]);
    expect([...grid.uvs]).toEqual([...grid.positions]);
  });
});