import * as rsa from "node-rsa";
import fetch, { Response } from "node-fetch";

export interface File {
   _id: string;
   type: "binary" | "text";
   name: string;
   time: string;
   preview: string;
   version: string;
}

export interface History {
   file: File;
   history: File[];
}

export default class SecureFile {
   private Server: string;
   private Username: string;
   private PrivateKey: string;
   constructor(server: string, username: string, private_key: string) {
      this.Server = server;
      this.Username = username;
      this.PrivateKey = private_key;
   }

   private async getCode() {
      let code_res = await fetch(this.Server + "/code?username=" + this.Username);
      //ToDo check status Codes
      let code = (await code_res.json()).code;
      let r = new rsa(this.PrivateKey, "pkcs1-pem");
      return { code: code, signature: r.sign(code).toString("base64") };
   }

   private async makeRequest(endpoint: string, method: "POST" | "GET" | "PUT" | "DELETE", query: any, body: Buffer) {
      let code = await this.getCode();
      query.code = code.code;
      query.signature = code.signature;
      let query_str = "?";
      let first = true;
      for (let key in query) {
         if (!first) query_str += "&";
         query_str += encodeURIComponent(key) + "=" + encodeURIComponent(query[key]);
         first = false;
      }
      return await fetch(this.Server + endpoint + query_str, { method: method, body: body });
   }

   async list(folder?: string): Promise<File[]> {
      if (!folder) folder = "root";
      let res = await this.makeRequest("/files", "GET", { folder: folder }, undefined)
      statusParser(res);
      return await res.json();
   }

   async create(name: string, data: Buffer, type: "text" | "binary", folder?: string, preview?: Buffer): Promise<File> {
      let res = await this.makeRequest("/files", "POST", { type: type, name: name, preview: preview, folder: folder }, data)
      statusParser(res);
      return res.json();
   }

   async get(id: string, version?: string): Promise<Buffer> {
      let res: Response;
      if (typeof version === "string") {
         res = await this.makeRequest(`/files/${id}/history/${version}`, "GET", {}, undefined);
      } else {
         res = await this.makeRequest("/files/" + id, "GET", {}, undefined);
      }
      statusParser(res);
      return res.buffer();
   }

   async update(id: string, data: Buffer, preview?: Buffer): Promise<File> {
      let put: any = {};
      if (preview) put.preview = preview;
      let res = await this.makeRequest("/files/" + id, "PUT", put, data);
      statusParser(res);
      return res.json();
   }

   async delete(id: string): Promise<boolean> {
      let res = await this.makeRequest("/files/" + id, "DELETE", {}, undefined);
      statusParser(res);
      return res.json();
   }

   async history(id: string): Promise<History> {
      let res = await this.makeRequest(`/files/${id}/history`, "GET", {}, undefined);
      statusParser(res);
      return res.json();
   }
}

export class Unauthorized extends Error {
   constructor() {
      super("Not authorized");
   }
}

export class NotFound extends Error {
   constructor() {
      super("Not found");
   }
}

export class BadRequest extends Error {
   constructor() {
      super("Bad request");
   }
}

function statusParser(res: Response) {
   if (res.status !== 200) {
      switch (res.status) {
         case 400:
            throw new BadRequest();
         case 404:
            throw new NotFound();
         case 403:
            throw new Unauthorized();
         default:
            throw new Error(res.statusText);
      }
   }
}