import { gl, ext } from './Renderer.js'

export class Mesh {
    
    static #vaos = []
    static #vbos = []

    #vertexCount
    #count
    #id
    #indicies

    constructor(vertexCount) {
        this.#id = ext.createVertexArrayOES()
        ext.bindVertexArrayOES(this.#id)
        Mesh.#vaos.push(this.#id)
        this.#vertexCount = vertexCount
        this.#count = 0
        this.#indicies = 0
    }

    store(data, dim) {
        let id = gl.createBuffer()
        Mesh.#vbos.push(id)
        gl.bindBuffer(gl.ARRAY_BUFFER, id)
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW)
        gl.vertexAttribPointer(this.#count, dim, gl.FLOAT, gl.FALSE, 0, 0)
        gl.enableVertexAttribArray(this.#count)
        this.#count++;
        return this
    }

    indicies(data) {
        let id = gl.createBuffer()
        Mesh.#vbos.push(id)
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, id)
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(data), gl.STATIC_DRAW)
        this.#indicies = data.length
        return this
    }

    finish() {
        this.unbind()
        return this
    }

    bind() {
        ext.bindVertexArrayOES(this.#id)
        for(let i = 0; i < this.#count; i++) {
            gl.enableVertexAttribArray(i)
        }
    }

    unbind() {
        ext.bindVertexArrayOES(null)
        for(let i = 0; i < this.#count; i++) {
            gl.disableVertexAttribArray(i)
        }
    }

    draw() {
        if(this.#indicies > 0) {
            gl.drawElements(gl.TRIANGLES, this.#indicies, gl.UNSIGNED_SHORT, 0)
        } else {
            gl.drawArrays(gl.TRIANGLES, 0, this.#vertexCount)
        }
    }

}