import { Injectable } from '@nestjs/common';
import {
  FullMime,
  ImageMime,
  SupportedMimeCategory
} from 'picsur-shared/dist/dto/mimes.dto';
import { AsyncFailable, Fail } from 'picsur-shared/dist/types';
import { QOIColorSpace, QOIencode } from 'qoi-img';
import { ImageResult } from './imageresult';
import { UniversalSharp } from './universal-sharp';

@Injectable()
export class ImageProcessorService {
  public async process(
    image: Buffer,
    mime: FullMime,
  ): AsyncFailable<ImageResult> {
    if (mime.type === SupportedMimeCategory.Image) {
      return await this.processStill(image, mime);
    } else if (mime.type === SupportedMimeCategory.Animation) {
      return await this.processAnimation(image, mime);
    } else {
      return Fail('Unsupported mime type');
    }
  }

  private async processStill(
    image: Buffer,
    mime: FullMime,
  ): AsyncFailable<ImageResult> {
    let processedMime = mime.mime;

    let sharpImage = UniversalSharp(image, mime);
    processedMime = ImageMime.QOI;

    sharpImage = sharpImage.toColorspace('srgb');

    const metadata = await sharpImage.metadata();
    const pixels = await sharpImage.raw().toBuffer();

    if (
      metadata.hasAlpha === undefined ||
      metadata.width === undefined ||
      metadata.height === undefined
    )
      return Fail('Invalid image');

    if (metadata.width >= 32768 || metadata.height >= 32768) {
      return Fail('Image too large');
    }

    // Png can be more efficient than QOI, but its just sooooooo slow
    const qoiImage = QOIencode(pixels, {
      channels: metadata.hasAlpha ? 4 : 3,
      colorspace: QOIColorSpace.SRGB,
      height: metadata.height,
      width: metadata.width,
    });

    return {
      image: qoiImage,
      mime: processedMime,
    };
  }

  private async processAnimation(
    image: Buffer,
    mime: FullMime,
  ): AsyncFailable<ImageResult> {
    // Apng and gif are stored as is for now
    return {
      image: image,
      mime: mime.mime,
    };
  }
}