import { Pipe, PipeTransform } from "@angular/core";

// Transforms a filesize in bytes to a human readable decimal filesize using SI prefixes
@Pipe({
  name: "filesize",
  standalone: false,
})
export class FilesizePipe implements PipeTransform {
  transform(size: number): string {
    if (typeof size !== "number") {
      return "0";
    }

    const symbols = ["B", "KB", "MB", "GB", "TB"];
    const sizes = [1, 2 ** 10, 2 ** 20, 2 ** 30, 2 ** 40, 2 ** 50];

    let symbol = symbols[0];
    let base = sizes[0];

    if (size < sizes[1]) {
      return "<1 KB";
    } else if (size < sizes[2]) {
      symbol = symbols[1];
      base = sizes[1];
    } else if (size < sizes[3]) {
      symbol = symbols[2];
      base = sizes[2];
    } else if (size < sizes[4]) {
      symbol = symbols[3];
      base = sizes[3];
    } else if (size < sizes[5]) {
      symbol = symbols[4];
      base = sizes[4];
    } else {
      console.warn("file size symbol not supported");
    }

    const rounded = Math.round(size / base);
    return `${rounded} ${symbol}`;
  }
}