import { DataTextureLoader, LinearMipmapLinearFilter } from '../lib/three.module.js'

class TGALoader extends DataTextureLoader {
    constructor(manager) {
        super(manager)
    }

    parse(buffer) {
        // reference from vthibault, https://github.com/vthibault/roBrowser/blob/master/src/Loaders/Targa.js

        function tgaCheckHeader(header) {
            switch (header.image_type) {
                // check indexed type

                case TGA_TYPE_INDEXED:
                case TGA_TYPE_RLE_INDEXED:
                    if (header.colormap_length > 256 || header.colormap_size !== 24 || header.colormap_type !== 1) {
                        console.error('THREE.TGALoader: Invalid type colormap data for indexed type.')
                    }

                    break

                // check colormap type

                case TGA_TYPE_RGB:
                case TGA_TYPE_GREY:
                case TGA_TYPE_RLE_RGB:
                case TGA_TYPE_RLE_GREY:
                    if (header.colormap_type) {
                        console.error('THREE.TGALoader: Invalid type colormap data for colormap type.')
                    }

                    break

                // What the need of a file without data ?

                case TGA_TYPE_NO_DATA:
                    console.error('THREE.TGALoader: No data.')

                // Invalid type ?

                default:
                    console.error('THREE.TGALoader: Invalid type "%s".', header.image_type)
            }

            // check image width and height

            if (header.width <= 0 || header.height <= 0) {
                console.error('THREE.TGALoader: Invalid image size.')
            }

            // check image pixel size

            if (header.pixel_size !== 8 && header.pixel_size !== 16 && header.pixel_size !== 24 && header.pixel_size !== 32) {
                console.error('THREE.TGALoader: Invalid pixel size "%s".', header.pixel_size)
            }
        }

        // parse tga image buffer

        function tgaParse(use_rle, use_pal, header, offset, data) {
            let pixel_data, palettes

            const pixel_size = header.pixel_size >> 3
            const pixel_total = header.width * header.height * pixel_size

            // read palettes

            if (use_pal) {
                palettes = data.subarray(offset, (offset += header.colormap_length * (header.colormap_size >> 3)))
            }

            // read RLE

            if (use_rle) {
                pixel_data = new Uint8Array(pixel_total)

                let c, count, i
                let shift = 0
                const pixels = new Uint8Array(pixel_size)

                while (shift < pixel_total) {
                    c = data[offset++]
                    count = (c & 0x7f) + 1

                    // RLE pixels

                    if (c & 0x80) {
                        // bind pixel tmp array

                        for (i = 0; i < pixel_size; ++i) {
                            pixels[i] = data[offset++]
                        }

                        // copy pixel array

                        for (i = 0; i < count; ++i) {
                            pixel_data.set(pixels, shift + i * pixel_size)
                        }

                        shift += pixel_size * count
                    } else {
                        // raw pixels

                        count *= pixel_size

                        for (i = 0; i < count; ++i) {
                            pixel_data[shift + i] = data[offset++]
                        }

                        shift += count
                    }
                }
            } else {
                // raw pixels

                pixel_data = data.subarray(offset, (offset += use_pal ? header.width * header.height : pixel_total))
            }

            return {
                pixel_data: pixel_data,
                palettes: palettes
            }
        }

        function tgaGetImageData8bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image, palettes) {
            const colormap = palettes
            let color,
                i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i++) {
                    color = image[i]
                    imageData[(x + width * y) * 4 + 3] = 255
                    imageData[(x + width * y) * 4 + 2] = colormap[color * 3 + 0]
                    imageData[(x + width * y) * 4 + 1] = colormap[color * 3 + 1]
                    imageData[(x + width * y) * 4 + 0] = colormap[color * 3 + 2]
                }
            }

            return imageData
        }

        function tgaGetImageData16bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {
            let color,
                i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i += 2) {
                    color = image[i + 0] + (image[i + 1] << 8) // Inversed ?
                    imageData[(x + width * y) * 4 + 0] = (color & 0x7c00) >> 7
                    imageData[(x + width * y) * 4 + 1] = (color & 0x03e0) >> 2
                    imageData[(x + width * y) * 4 + 2] = (color & 0x001f) >> 3
                    imageData[(x + width * y) * 4 + 3] = color & 0x8000 ? 0 : 255
                }
            }

            return imageData
        }

        function tgaGetImageData24bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {
            let i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i += 3) {
                    imageData[(x + width * y) * 4 + 3] = 255
                    imageData[(x + width * y) * 4 + 2] = image[i + 0]
                    imageData[(x + width * y) * 4 + 1] = image[i + 1]
                    imageData[(x + width * y) * 4 + 0] = image[i + 2]
                }
            }

            return imageData
        }

        function tgaGetImageData32bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {
            let i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i += 4) {
                    imageData[(x + width * y) * 4 + 2] = image[i + 0]
                    imageData[(x + width * y) * 4 + 1] = image[i + 1]
                    imageData[(x + width * y) * 4 + 0] = image[i + 2]
                    imageData[(x + width * y) * 4 + 3] = image[i + 3]
                }
            }

            return imageData
        }

        function tgaGetImageDataGrey8bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {
            let color,
                i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i++) {
                    color = image[i]
                    imageData[(x + width * y) * 4 + 0] = color
                    imageData[(x + width * y) * 4 + 1] = color
                    imageData[(x + width * y) * 4 + 2] = color
                    imageData[(x + width * y) * 4 + 3] = 255
                }
            }

            return imageData
        }

        function tgaGetImageDataGrey16bits(imageData, y_start, y_step, y_end, x_start, x_step, x_end, image) {
            let i = 0,
                x,
                y
            const width = header.width

            for (y = y_start; y !== y_end; y += y_step) {
                for (x = x_start; x !== x_end; x += x_step, i += 2) {
                    imageData[(x + width * y) * 4 + 0] = image[i + 0]
                    imageData[(x + width * y) * 4 + 1] = image[i + 0]
                    imageData[(x + width * y) * 4 + 2] = image[i + 0]
                    imageData[(x + width * y) * 4 + 3] = image[i + 1]
                }
            }

            return imageData
        }

        function getTgaRGBA(data, width, height, image, palette) {
            let x_start, y_start, x_step, y_step, x_end, y_end

            switch ((header.flags & TGA_ORIGIN_MASK) >> TGA_ORIGIN_SHIFT) {
                default:
                case TGA_ORIGIN_UL:
                    x_start = 0
                    x_step = 1
                    x_end = width
                    y_start = 0
                    y_step = 1
                    y_end = height
                    break

                case TGA_ORIGIN_BL:
                    x_start = 0
                    x_step = 1
                    x_end = width
                    y_start = height - 1
                    y_step = -1
                    y_end = -1
                    break

                case TGA_ORIGIN_UR:
                    x_start = width - 1
                    x_step = -1
                    x_end = -1
                    y_start = 0
                    y_step = 1
                    y_end = height
                    break

                case TGA_ORIGIN_BR:
                    x_start = width - 1
                    x_step = -1
                    x_end = -1
                    y_start = height - 1
                    y_step = -1
                    y_end = -1
                    break
            }

            if (use_grey) {
                switch (header.pixel_size) {
                    case 8:
                        tgaGetImageDataGrey8bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image)
                        break

                    case 16:
                        tgaGetImageDataGrey16bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image)
                        break

                    default:
                        console.error('THREE.TGALoader: Format not supported.')
                        break
                }
            } else {
                switch (header.pixel_size) {
                    case 8:
                        tgaGetImageData8bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image, palette)
                        break

                    case 16:
                        tgaGetImageData16bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image)
                        break

                    case 24:
                        tgaGetImageData24bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image)
                        break

                    case 32:
                        tgaGetImageData32bits(data, y_start, y_step, y_end, x_start, x_step, x_end, image)
                        break

                    default:
                        console.error('THREE.TGALoader: Format not supported.')
                        break
                }
            }

            // Load image data according to specific method
            // let func = 'tgaGetImageData' + (use_grey ? 'Grey' : '') + (header.pixel_size) + 'bits';
            // func(data, y_start, y_step, y_end, x_start, x_step, x_end, width, image, palette );
            return data
        }

        // TGA constants

        const TGA_TYPE_NO_DATA = 0,
            TGA_TYPE_INDEXED = 1,
            TGA_TYPE_RGB = 2,
            TGA_TYPE_GREY = 3,
            TGA_TYPE_RLE_INDEXED = 9,
            TGA_TYPE_RLE_RGB = 10,
            TGA_TYPE_RLE_GREY = 11,
            TGA_ORIGIN_MASK = 0x30,
            TGA_ORIGIN_SHIFT = 0x04,
            TGA_ORIGIN_BL = 0x00,
            TGA_ORIGIN_BR = 0x01,
            TGA_ORIGIN_UL = 0x02,
            TGA_ORIGIN_UR = 0x03

        if (buffer.length < 19) console.error('THREE.TGALoader: Not enough data to contain header.')

        let offset = 0

        const content = new Uint8Array(buffer),
            header = {
                id_length: content[offset++],
                colormap_type: content[offset++],
                image_type: content[offset++],
                colormap_index: content[offset++] | (content[offset++] << 8),
                colormap_length: content[offset++] | (content[offset++] << 8),
                colormap_size: content[offset++],
                origin: [content[offset++] | (content[offset++] << 8), content[offset++] | (content[offset++] << 8)],
                width: content[offset++] | (content[offset++] << 8),
                height: content[offset++] | (content[offset++] << 8),
                pixel_size: content[offset++],
                flags: content[offset++]
            }

        // check tga if it is valid format

        tgaCheckHeader(header)

        if (header.id_length + offset > buffer.length) {
            console.error('THREE.TGALoader: No data.')
        }

        // skip the needn't data

        offset += header.id_length

        // get targa information about RLE compression and palette

        let use_rle = false,
            use_pal = false,
            use_grey = false

        switch (header.image_type) {
            case TGA_TYPE_RLE_INDEXED:
                use_rle = true
                use_pal = true
                break

            case TGA_TYPE_INDEXED:
                use_pal = true
                break

            case TGA_TYPE_RLE_RGB:
                use_rle = true
                break

            case TGA_TYPE_RGB:
                break

            case TGA_TYPE_RLE_GREY:
                use_rle = true
                use_grey = true
                break

            case TGA_TYPE_GREY:
                use_grey = true
                break
        }

        //

        const imageData = new Uint8Array(header.width * header.height * 4)
        const result = tgaParse(use_rle, use_pal, header, offset, content)
        getTgaRGBA(imageData, header.width, header.height, result.pixel_data, result.palettes)

        return {
            data: imageData,
            width: header.width,
            height: header.height,
            flipY: true,
            generateMipmaps: true,
            minFilter: LinearMipmapLinearFilter
        }
    }
}

export { TGALoader }