import { Buffer } from "node:buffer";

import { nativeImage } from "electron";

import { fetchDesktopApiURL, resolveDesktopApiURL } from "../transport/api-client";

export interface ImageAssetBlob {
  blob: Blob;
  width: number;
  height: number;
  fileName: string;
}

export interface CropRect {
  x: number;
  y: number;
  width: number;
  height: number;
}

const passthroughImageTypes = new Set(["image/png", "image/jpeg", "image/jpg", "image/gif"]);

function buildDesktopAssetFallbackURL(publicAssetUrl: URL): string | null {
  if (!publicAssetUrl.pathname.startsWith("/api/public/assets/")) {
    return null;
  }

  const token = publicAssetUrl.pathname.slice("/api/public/assets/".length);
  if (!token) {
    return null;
  }

  const fallbackURL = new URL(resolveDesktopApiURL(`/api/desktop/content/assets/${token}`));
  publicAssetUrl.searchParams.forEach((value, key) => {
    fallbackURL.searchParams.set(key, value);
  });
  fallbackURL.searchParams.set("format", "png");
  return fallbackURL.toString();
}

export function buildAssetURLCandidates(sourceUrl: string): string[] {
  const trimmed = sourceUrl.trim();
  if (!trimmed) {
    return [];
  }

  if (/^(data|blob):/i.test(trimmed)) {
    return [trimmed];
  }

  const candidates: string[] = [];
  const pushCandidate = (value: string) => {
    if (!candidates.includes(value)) {
      candidates.push(value);
    }
  };

  try {
    const parsed = new URL(trimmed, resolveDesktopApiURL("/"));

    if (parsed.pathname.startsWith("/api/")) {
      const apiAssetUrl = new URL(resolveDesktopApiURL(`${parsed.pathname}${parsed.search}`));
      if (apiAssetUrl.pathname.startsWith("/api/public/assets/")) {
        apiAssetUrl.searchParams.set("format", "png");
      }
      pushCandidate(apiAssetUrl.toString());

      const desktopAssetFallbackURL = buildDesktopAssetFallbackURL(apiAssetUrl);
      if (desktopAssetFallbackURL) {
        pushCandidate(desktopAssetFallbackURL);
      }
    }

    pushCandidate(parsed.toString());
  } catch {
    pushCandidate(trimmed);
  }

  return candidates;
}

function shouldUseDesktopAssetFetch(candidate: string): boolean {
  try {
    return new URL(candidate).pathname.startsWith("/api/desktop/content/assets/");
  } catch {
    return false;
  }
}

function fileNameForImageType(sourceType: string): string {
  if (sourceType === "image/gif") {
    return "image.gif";
  }
  if (sourceType === "image/jpeg" || sourceType === "image/jpg") {
    return "image.jpg";
  }
  return "image.png";
}

export async function fetchImageAssetBlob(sourceUrl: string): Promise<ImageAssetBlob | null> {
  for (const candidate of buildAssetURLCandidates(sourceUrl)) {
    const response = await (
      shouldUseDesktopAssetFetch(candidate) ? fetchDesktopApiURL(candidate) : fetch(candidate)
    ).catch(() => null);
    if (!response?.ok) {
      continue;
    }

    const sourceBlob = await response.blob().catch(() => null);
    if (!sourceBlob || !sourceBlob.type.startsWith("image/")) {
      continue;
    }

    const image = nativeImage.createFromBuffer(Buffer.from(await sourceBlob.arrayBuffer()));
    if (image.isEmpty()) {
      continue;
    }

    const size = image.getSize();
    const sourceType = sourceBlob.type.toLowerCase();
    if (passthroughImageTypes.has(sourceType)) {
      return {
        blob: sourceBlob,
        width: size.width,
        height: size.height,
        fileName: fileNameForImageType(sourceType),
      };
    }

    return {
      blob: new Blob([new Uint8Array(image.toPNG())], { type: "image/png" }),
      width: size.width,
      height: size.height,
      fileName: "image.png",
    };
  }

  return null;
}

export function getCenteredCropRect(width: number, height: number, ratio: number): CropRect {
  let cropWidth = width;
  let cropHeight = cropWidth / ratio;
  if (cropHeight > height) {
    cropHeight = height;
    cropWidth = cropHeight * ratio;
  }

  return {
    x: (width - cropWidth) / 2,
    y: (height - cropHeight) / 2,
    width: cropWidth,
    height: cropHeight,
  };
}

export async function cropImageAssetBlob(source: ImageAssetBlob, ratio: number): Promise<ImageAssetBlob | null> {
  const image = nativeImage.createFromBuffer(Buffer.from(await source.blob.arrayBuffer()));
  if (image.isEmpty()) {
    return null;
  }

  const crop = getCenteredCropRect(source.width, source.height, ratio);
  const cropped = image.crop({
    x: Math.max(0, Math.round(crop.x)),
    y: Math.max(0, Math.round(crop.y)),
    width: Math.max(1, Math.round(crop.width)),
    height: Math.max(1, Math.round(crop.height)),
  });
  if (cropped.isEmpty()) {
    return null;
  }

  const size = cropped.getSize();
  return {
    blob: new Blob([new Uint8Array(cropped.toPNG())], { type: "image/png" }),
    width: size.width,
    height: size.height,
    fileName: "image.png",
  };
}