// luma.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

import {Vector3, Matrix4} from '@math.gl/core';
import {ShaderModule} from '../../lib/shader-module/shader-module';
import type {NumberArray3, NumberArray16} from '@math.gl/core';

type ProjectionProps = {
  modelMatrix?: Readonly<Matrix4 | NumberArray16>;
  viewMatrix?: Readonly<Matrix4 | NumberArray16>;
  projectionMatrix?: Readonly<Matrix4 | NumberArray16>;
  cameraPositionWorld?: Readonly<Vector3 | NumberArray3>;
};

const IDENTITY_MATRIX: NumberArray16 = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];

const DEFAULT_MODULE_OPTIONS: ProjectionProps = {
  modelMatrix: IDENTITY_MATRIX,
  viewMatrix: IDENTITY_MATRIX,
  projectionMatrix: IDENTITY_MATRIX,
  cameraPositionWorld: [0, 0, 0]
};

function getUniforms(opts: ProjectionProps = DEFAULT_MODULE_OPTIONS, prevUniforms = {}) {
  // const viewProjectionInverse = viewProjection.invert();
  // viewInverseMatrix: view.invert(),
  // viewProjectionInverseMatrix: viewProjectionInverse

  const uniforms: Record<string, any> = {};
  if (opts.modelMatrix !== undefined) {
    uniforms.modelMatrix = opts.modelMatrix;
  }
  if (opts.viewMatrix !== undefined) {
    uniforms.viewMatrix = opts.viewMatrix;
  }
  if (opts.projectionMatrix !== undefined) {
    uniforms.projectionMatrix = opts.projectionMatrix;
  }
  if (opts.cameraPositionWorld !== undefined) {
    uniforms.cameraPositionWorld = opts.cameraPositionWorld;
  }

  // COMPOSITE UNIFORMS
  if (opts.projectionMatrix !== undefined && opts.viewMatrix !== undefined) {
    uniforms.viewProjectionMatrix = new Matrix4(opts.projectionMatrix).multiplyRight(
      opts.viewMatrix
    );
  }

  return uniforms;
}

const common = /* glsl */ `\
varying vec4 project_vPositionWorld;
varying vec3 project_vNormalWorld;

vec4 project_getPosition_World() {
  return project_vPositionWorld;
}

vec3 project_getNormal_World() {
  return project_vNormalWorld;
}
`;

const vs = `\
${common}

// Unprefixed uniforms
uniform mat4 modelMatrix;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;
uniform mat4 viewProjectionMatrix;
uniform vec3 cameraPositionWorld;

struct World {
  vec3 position;
  vec3 normal;
};

World world;

void project_setPosition(vec4 position) {
  project_vPositionWorld = position;
}

void project_setNormal(vec3 normal) {
  project_vNormalWorld = normal;
}

void project_setPositionAndNormal_World(vec3 position, vec3 normal) {
  world.position = position;
  world.normal = normal;
}

void project_setPositionAndNormal_Model(vec3 position, vec3 normal) {
  world.position = (modelMatrix * vec4(position, 1.)).xyz;
  world.normal = mat3(modelMatrix) * normal;
}

vec4 project_model_to_clipspace(vec4 position) {
  return viewProjectionMatrix * modelMatrix * position;
}

vec4 project_model_to_clipspace(vec3 position) {
  return viewProjectionMatrix * modelMatrix * vec4(position, 1.);
}

vec4 project_world_to_clipspace(vec3 position) {
  return viewProjectionMatrix * vec4(position, 1.);
}

vec4 project_view_to_clipspace(vec3 position) {
  return projectionMatrix * vec4(position, 1.);
}

vec4 project_to_clipspace(vec3 position) {
  return viewProjectionMatrix * vec4(position, 1.);
}
`;

const fs = `
${common}\
`;

/**
 * Projects coordinates
 */
export const project = {
  name: 'project',
  getUniforms,
  vs,
  fs
} as const satisfies ShaderModule<ProjectionProps, ProjectionProps>;