import { Mesh } from "../core/mesh";
import { vec3 } from "../types/vec3";
import { vec2 } from "../types/vec2";
import { Color } from "../types/color";
import { GlobalContext } from "../core/global";
import { MeshBuilder } from "../utils/mesh-builder";

export function createBuiltinMesh(gl: WebGL2RenderingContext)
{
    return {
        quad: quad(gl),
        screenQuad: screenQuad(gl),
        cube: cube(gl),
    };
}

function quad(gl: WebGL2RenderingContext)
{
    const quad = new Mesh(gl);
    quad.verts = [
        vec3(-.5, -.5, 0),
        vec3(.5, -.5, 0),
        vec3(.5, .5, 0),
        vec3(-.5, .5, 0),
    ];
    quad.triangles = [
        0, 1, 3,
        1, 2, 3,
    ];
    quad.uvs = [
        vec2(0, 0),
        vec2(1, 0),
        vec2(1, 1),
        vec2(0, 1)
    ];
    quad.calculateNormals();
    quad.name = "mesh_quad";
    return quad;
}

function screenQuad(gl: WebGL2RenderingContext)
{
    const screenQuad = new Mesh(gl);
    screenQuad.verts = [
        vec3(-1, -1, 0),
        vec3(1, -1, 0),
        vec3(1, 1, 0),
        vec3(-1, 1, 0),
    ];
    screenQuad.triangles = [
        0, 1, 3,
        1, 2, 3,
    ];
    screenQuad.uvs = [
        vec2(0, 0),
        vec2(1, 0),
        vec2(1, 1),
        vec2(0, 1)
    ];
    screenQuad.calculateNormals();
    screenQuad.name = "mesh_screen_quad";
    return screenQuad;
}

function cube(gl: WebGL2RenderingContext)
{
    const verts = [
        vec3(-.5, -.5, -.5),
        vec3(.5, -.5, -.5),
        vec3(.5, .5, -.5),
        vec3(-.5, .5, -.5),
        vec3(-.5, -.5, .5),
        vec3(.5, -.5, .5),
        vec3(.5, .5, .5),
        vec3(-.5, .5, .5),
    ];
    const uvs = [
        vec2(0, 0),
        vec2(1, 0),
        vec2(1, 1),
        vec2(0, 1)
    ];
    const mb = new MeshBuilder(24, gl);
    mb.addPolygon([
        verts[1],
        verts[0],
        verts[3],
        verts[2],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    mb.addPolygon([
        verts[5],
        verts[1],
        verts[2],
        verts[6],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    mb.addPolygon([
        verts[4],
        verts[5],
        verts[6],
        verts[7],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    mb.addPolygon([
        verts[0],
        verts[4],
        verts[7],
        verts[3],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    mb.addPolygon([
        verts[7],
        verts[6],
        verts[2],
        verts[3],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    mb.addPolygon([
        verts[0],
        verts[1],
        verts[5],
        verts[4],
    ],
        [
            uvs[0],
            uvs[1],
            uvs[2],
            uvs[3]
        ]);
    const mesh = mb.toMesh();
    mesh.name = "mesh_cube";
    return mesh;
}