import { action, observable, runInAction } from "mobx";
import URI from "urijs";
import filterOutUndefined from "../../../Core/filterOutUndefined";
import loadArrayBuffer from "../../../Core/loadArrayBuffer";
import loadBlob, { isZip, parseZipArrayBuffers } from "../../../Core/loadBlob";
import TerriaError, { TerriaErrorSeverity } from "../../../Core/TerriaError";
import { getName } from "../../../ModelMixins/CatalogMemberMixin";
import GltfMixin from "../../../ModelMixins/GltfMixin";
import AssImpCatalogItemTraits from "../../../Traits/TraitsClasses/AssImpCatalogItemTraits";
import CommonStrata from "../../Definition/CommonStrata";
import CreateModel from "../../Definition/CreateModel";
import HasLocalData from "../../HasLocalData";
import proxyCatalogItemUrl from "../proxyCatalogItemUrl";
import { GlTf } from "./GLTF";

// List of supported image formats from https://developer.mozilla.org/en-US/docs/Web/Media/Formats/Image_types
// + Cesium adds support for ktx2
const supportedTextureExtensions = [
  "apng",
  "avif",
  "gif",
  "jpg",
  "jpeg",
  "jfif",
  "pjpeg",
  "pjp",
  "png",
  "svg",
  "webp",
  "ktx2"
];

export default class AssImpCatalogItem
  extends GltfMixin(CreateModel(AssImpCatalogItemTraits))
  implements HasLocalData
{
  @observable
  protected gltfModelUrl: string | undefined;

  static readonly type = "assimp";

  get type() {
    return AssImpCatalogItem.type;
  }

  @observable hasLocalData = false;

  @action
  setFileInput(file: File | Blob) {
    const dataUrl = URL.createObjectURL(file);
    this.setTrait(CommonStrata.user, "urls", [dataUrl]);
    this.hasLocalData = true;
  }

  protected async forceLoadMapItems(): Promise<void> {
    const urls =
      this.urls.length > 0 ? this.urls : filterOutUndefined([this.url]);
    if (urls.length === 0) return;

    let baseUrl = this.baseUrl;
    // If no baseUrl provided - but we have a single URL -> construct baseUrl from that
    if (!baseUrl && urls.length === 1) {
      const uri = new URI(urls[0]);
      baseUrl = uri.origin() + uri.directory() + "/";
    }

    // TODO: revokeObjectURL() for all created objects

    /** Maps paths to absolute URLs
     * This is used to substitute paths in GlTf (eg buffer or image/texture paths)
     * - All local data (eg files output from assimp - or locally uploaded zip file) - use `createObjectURL` to get URL to local blob
     * - All remote data will use absolute URLs
     *
     * For example
     * - **Remote data** - explicitly defined in `this.url` or `this.urls`
     *    - URL "http://localhost:3001/some-dir/some-file.jpg" (as defined in `url` or `urls`)
     *    - path in GlTf = "some-file.jpg"
     *    - So we replace gltf.images[i].uri "some-file.jpg" with "http://localhost:3001/some-dir/some-file.jpg" (using `dataUrls`)
     * - **Remote data** - implicitly references in 3D file
     *    - URL "http://localhost:3001/some-dir/some-collada-file.dae" (as defined in `url` or `urls`)
     *    - This Collada file internally references "some-file.jpg"
     *    - `baseUrl` is equal to "http://localhost:3001/some-dir/"
     *    - So we replace gltf.images[i].uri "some-file.jpg" with "http://localhost:3001/some-dir/some-file.jpg" (this is done post conversion to GlTf)
     * - **Local data** - from zip file
     *    - Upload zip file with "some-file.jpg"
     *    - Create local blob URL "blob:http://localhost:3001/some-blob-uuid"
     *    - So we replace gltf.images[i].uri "some-file.jpg" with "blob:http://localhost:3001/some-blob-uuid" (using `dataUrls`)
     */
    const dataUrls: Map<string, string> = new Map();

    /** List of files to input into `assimpjs`
     * This will be populated with all files downloaded using `url` or `urls` - and all files from downloaded/uploaded zip files
     */
    const fileArrayBuffers: {
      name: string;
      arrayBuffer: ArrayBuffer;
    }[] = [];

    let zipRootDir: string | undefined;
    await Promise.all(
      urls.map(async (url) => {
        // **Local data** - treat all URLs as zip if they have been uploaded
        if (isZip(url) || this.hasLocalData) {
          const blob = await loadBlob(proxyCatalogItemUrl(this, url));
          const zipFiles = await parseZipArrayBuffers(blob);
          zipFiles.forEach((zipFile, i) => {
            if (i === 0 && zipFile.isDirectory) {
              // If the first entry is a directory, we treat it as a root
              // directory that contains all the other files.
              zipRootDir = zipFile.fileName;
            }
            fileArrayBuffers.push({
              name: zipFile.fileName,
              arrayBuffer: zipFile.data
            });

            // Because these unzipped files are local - we need to create URL to local blob
            const blob = new Blob([zipFile.data]);
            const dataUrl = URL.createObjectURL(blob);
            // Push filename -> local data blob URI
            let fileName = zipFile.fileName;
            if (zipRootDir) {
              // This zip appears to have contents inside a root
              // directory. Rewrite file names relative to this root so that
              // assimp can correctly resolve relatively referenced assets.
              fileName = zipFile.fileName.startsWith(zipRootDir)
                ? zipFile.fileName.slice(zipRootDir.length)
                : zipFile.fileName;
            }
            dataUrls.set(fileName, dataUrl);
          });
        }
        // **Remote data** - explicitly defined in `url` or `urls`
        else {
          const arrayBuffer = await loadArrayBuffer(
            proxyCatalogItemUrl(this, url)
          );
          const uri = new URI(url);
          const name = uri.filename();
          fileArrayBuffers.push({
            name,
            arrayBuffer
          });

          // Because all these files are "remote", we want to substitute filename with absolute URL
          dataUrls.set(name, uri.absoluteTo(window.location.href).toString());
        }
      })
    );

    // Init assimpjs
    const assimpjs = (await import("assimpjs")).default;
    const ajs = await assimpjs();

    // Create assimpjs FileList object, and add the files
    let fileList = new ajs.FileList();
    for (let i = 0; i < fileArrayBuffers.length; i++) {
      fileList.AddFile(
        fileArrayBuffers[i].name,
        new Uint8Array(fileArrayBuffers[i].arrayBuffer)
      );
    }

    // Convert files to GlTf 2
    let result = ajs.ConvertFileList(fileList, "gltf2");
    const fileCount = result.FileCount();

    if (!result.IsSuccess() || fileCount == 0) {
      throw TerriaError.from(result.GetErrorCode(), {
        title: "Failed to convert files to GlTf"
      });
    }

    /** This is used so we only set `this.gltfModelUrl` after process has finished */
    let gltfModelUrl: string | undefined;
    /** List of unsupported texture URLs to show in warning message */
    const unsupportedTextures: string[] = [];

    // Go through files backward - as GlTf file is first (i==0), followed by dependencies (eg buffers, textures)
    // As we may need to correct paths in GlTf file. Dependencies are stored in browser - so we need to use local blob object URL before processing GlTf file
    for (let i = fileCount - 1; i >= 0; i--) {
      const file = result.GetFile(i);
      const path = file.GetPath();

      let arrayBuffer: ArrayBuffer = file.GetContent();

      // i === 0 is GlTf file
      // So we parse the file into JSON and edit paths for buffers, images, ...
      if (i === 0) {
        const file = new File([arrayBuffer], path);

        const gltfJson = JSON.parse(await file.text()) as GlTf;
        // Replace buffer file URIs
        // Buffer files are generated by Assimp - so we just replace the path with local Blob URL
        gltfJson.buffers?.forEach((buffer) => {
          if (!buffer.uri) return;

          const newUri = dataUrls.get(buffer.uri);
          console.log(
            `replacing GlTf buffer path \`${buffer.uri}\` with \`${newUri}\``
          );
          buffer.uri = newUri;
        });

        // Replace image file URIs
        // Image files are external to Assimp - so we do a bit more wrangling:
        // - Replace back slashes with forward slash
        // - Remove leading "./" or "//"
        // - See dataUrls for info on URL transformation
        gltfJson.images?.forEach((image) => {
          if (!image.uri) return;

          // Replace back slashes with forward slash
          let newUrl = image.uri.replace(/\\/g, "/");
          // Remove start "./" or "//" from uri
          if (newUrl.startsWith("//") || newUrl.startsWith("./")) {
            newUrl = newUrl.slice(2);
          }

          // If any unsupported image URIs are detected (by extension/suffix) then we show a warning message listing them
          if (
            !supportedTextureExtensions.some(
              (ext) => ext === new URI(newUrl).suffix()
            )
          ) {
            unsupportedTextures.push(image.uri);
          }

          // Do we have substitute URL in dataUrls (see dataUrls for more info)
          // This covers:
          // - Remote data - explicitly defined in `url` or `urls`
          // - Local data - from zip file
          if (dataUrls.has(newUrl)) {
            newUrl = dataUrls.get(newUrl)!;
          }
          // No substitute URL - so resolve URL to baseUrl (if defined)
          // This covers:
          // - Remote data - implicitly defined in 3D file
          else if (baseUrl) {
            newUrl = new URI(newUrl).absoluteTo(baseUrl).toString();
          }

          if (newUrl !== image.uri) {
            console.log(
              `replacing GlTf image path \`${image.uri}\` with \`${newUrl}\``
            );
            image.uri = newUrl;
          }
        });

        // TODO: Replace KHR_techniques_webgl extension shader URIs?
        // https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Archived/KHR_techniques_webgl/README.md#shader

        /** For some reason Cesium ignores textures if the KHR_materials_pbrSpecularGlossiness material extension is used and model has no normals.
         *
         * Here's the code that shades based on the diffuseTexture when that extension is in use: https://github.com/TerriaJS/cesium/blob/terriajs/Source/Scene/processPbrMaterials.js#L797
         * And it's inside this conditional: https://github.com/TerriaJS/cesium/blob/terriajs/Source/Scene/processPbrMaterials.js#L771
         *
         * For the moment - if we have images, we go through all materials and delete the extension
         */
        if (gltfJson.images && gltfJson.images.length > 0) {
          gltfJson.materials?.forEach((material) => {
            if (material.extensions?.KHR_materials_pbrSpecularGlossiness)
              material.extensions.KHR_materials_pbrSpecularGlossiness =
                undefined;
          });
        }

        // Turn GlTf back into array buffer - this overwrites existing GlTf
        arrayBuffer = Buffer.from(JSON.stringify(gltfJson));
      }

      // Convert assimp output file to blob and create object URL
      const blob = new Blob([arrayBuffer]);
      const dataUrl = URL.createObjectURL(blob);
      // Add map from filePath to local blob URL
      // This will be used to substitute paths when processing GlTf file
      dataUrls.set(path, dataUrl);

      // GlTf file
      if (i === 0) {
        gltfModelUrl = dataUrl;
      }
    }

    runInAction(() => {
      this.gltfModelUrl = gltfModelUrl;
    });

    if (unsupportedTextures.length > 0)
      throw new TerriaError({
        severity: TerriaErrorSeverity.Warning,
        title: "Unsupported texture formats",
        message: `Catalog item \`"${getName(
          this
        )}"\` has unsupported texture formats for the following:  \n${unsupportedTextures.map(
          (path) => `- \`${path}\`\n`
        )}\n\nThe model may not display correctly.  \n\nList of supported formats: ${supportedTextureExtensions
          .map((ext) => `\`${ext}\``)
          .join(", ")}`
      });
  }
}