import { MeshAttributeData } from './vertex.js'
import { Indices } from './index.js'
import { assignOptions } from '/src/utils/index.js'

export const PrimitiveTopology = Object.freeze({
    PointList: 'point-list',
    LineList: 'line-list',
    LineStrip: 'line-strip',
    TriangleList: 'triangle-list',
    TriangleStrip: 'triangle-strip'
})

export const IndexFormat = Object.freeze({
    Uint16: 'uint16',
    Uint32: 'uint32'
})

export const FrontFace = Object.freeze({
    Ccw: 'ccw',
    Cw: 'cw'
})

export const CullMode = Object.freeze({
    None: 'none',
    Front: 'front',
    Back: 'back'
})

export class PrimitiveState {
    #topology = PrimitiveTopology.TriangleList
    #stripIndexFormat
    #frontFace = FrontFace.Ccw
    #cullMode = CullMode.None

    #unclippedDepth = false

    /**
     * @param {GPUIndexFormat} stripIndexFormat 
     * @param {Object} options 
     * @param {GPUPrimitiveTopology} [options.topology]
     * @param {GPUFrontFace} [options.frontFace]
     * @param {GPUCullMode} [options.cullMode]
     * @param {boolean} [options.unclippedDepth]
     */
    constructor(stripIndexFormat, options) {
        this.#stripIndexFormat = stripIndexFormat
        assignOptions(this, options)
    }

    get topology() { return this.#topology }
    get stripIndexFormat() { return this.#stripIndexFormat }
    get frontFace() { return this.#frontFace }
    get cullMode() { return this.#cullMode }
    get unclippedDepth() { return this.#unclippedDepth }
}

export class Mesh {
    /** @type {PrimitiveTopology} */
    topology
    /** @type {Map<VertexAttributeId, MeshAttributeData>} */
    attributes = new Map()
    /** @type {Indices} */
    indices
}