import * as config from "../config.json"
import { Lock, Observable } from "@hibas123/utils"

import SecureFile, { IFile } from "@hibas123/secure-file-wrapper";
import * as b64 from "./helper/base64"

export class HttpError extends Error {
   constructor(public status: number, public statusText: string) {
      super(statusText);
      console.log(statusText);
   }
}

// const newSymbol = Symbol("Symbol for new Notes")

export interface Note {
   _id: string;
   folder: string;
   time: Date;
}

interface DBNote extends Note {
   __value: Uint8Array;
   preview: Uint8Array;
}

export interface BaseNote extends Note {
   preview: string;
}

export interface ViewNote extends BaseNote {
   __value: string;
}

import * as aesjs from "aes-js";
import { sha256 } from "js-sha256"
import clonedeep = require("lodash.clonedeep");
import * as uuidv4 from "uuid/v4"
import IDB from "./helper/indexeddb";
import { Transaction } from "idb";
import Notifications, { MessageType } from "./notifications";

const Encoder = new TextEncoder();
const Decoder = new TextDecoder();

enum OpLogType {
   CREATE,
   CHANGE,
   DELETE
}

interface OpLog {
   /**
    * Type of operation
    */
   type: OpLogType;

   /**
    * The value
    */
   values: {
      value: Uint8Array,
      preview: Uint8Array
   };

   /**
    * Date of change
    */
   date: Date;
}

export type VaultList = { name: string, encrypted: boolean, id: string }[];

export interface IVault {
   name: string;
   id: string;
   encrypted: boolean;
   getAllNotes(): Promise<BaseNote[]>;
   searchNote(term: string): Promise<BaseNote[]>
   newNote(): ViewNote;
   saveNote(note: ViewNote, date?: Date): Promise<void>;
   getNote(id: string): Promise<ViewNote>;
   deleteNote(id: string): Promise<void>;
}

const awaitTimeout = (ms: number) => new Promise<void>(resolve => setTimeout(resolve, ms));

class NotesProvider {
   private notesObservableServer = new Observable<Note>()
   public notesObservable = this.notesObservableServer.getPublicApi()

   private syncObservableServer = new Observable<boolean>()
   /**
    * Will send false once finished and true on start
    */
   public syncObservable = this.syncObservableServer.getPublicApi()

   private database = new IDB("notes", ["notes", "oplog"]);
   private noteDB = this.database.getStore<DBNote>("notes");
   private oplogDB = this.database.getStore<{ id: string, logs: OpLog[] }>("oplog");

   private vaultKeys = new Map<string, Uint8Array>();


   public apiLock = new Lock();
   public apiLockRls = this.apiLock.getLock()

   private syncLock = new Lock();

   private _secureFile: SecureFile;

   private generalEncryption: Uint8Array = undefined;

   private syncedObservableServer = new Observable<boolean>();
   public syncedObservable = this.syncedObservableServer.getPublicApi();

   public async isSynced() {
      return (await this.oplogDB.getAll()).length <= 0
   }

   private _name;
   public get name() {
      return this._name;
   }

   loginRequired() {
      return !localStorage.getItem("refreshtoken") || !this.generalEncryption;
   }

   login() {
      window.location.href = `${config.auth_server}/auth?client_id=${config.client_id}&scope=${config.permission}&redirect_uri=${encodeURIComponent(config.callback_url)}&response_type=code`
   }

   async getToken(code: string) {
      let req = await fetch(`${config.auth_server}/api/oauth/refresh?grant_type=authorization_code&client_id=${config.client_id}&code=${code}`);
      let res = await req.json();
      if (!res.error) {
         localStorage.setItem("refreshtoken", res.token);
         localStorage.setItem("name", res.profile.name);
         this._name = res.profile.name;
         let kb = this.passwordToKey(res.profile.enc_key);
         localStorage.setItem("enc_key", b64.encode(kb));
         this.generalEncryption = kb
      } else {
         return "Invalid Code"
      }
   }

   constructor(public readonly baseurl = "") {
      this._secureFile = new SecureFile(config.secure_file_server);
      this._secureFile.jwtObservable.subscribe(async (callback) => {
         try {
            let jwt = await this.getJWT();
            callback(null, jwt);
         } catch (err) {
            callback(err, null);
         }
      })

      let key = localStorage.getItem("enc_key");
      if (key) {
         this.generalEncryption = b64.decode(key)
      }
      this._name = localStorage.getItem("name");
   }

   public async start() {
      const next = () => {
         setTimeout(() => {
            this.sync().then(() => next);
         }, 30000)
      }
      this.syncedObservableServer.send((await this.oplogDB.getAll()).length <= 0);
      let prs = this.apiLockRls.then(lock => lock.release());
      prs.then(() => awaitTimeout(5000)).then(() => this.sync()).then(() => next());
      return prs;
   }

   private async getJWT() {
      let lock = await this.apiLock.getLock()
      try {
         console.log("Getting JWT");
         let req = await fetch(config.auth_server + "/api/oauth/jwt?refreshtoken=" + localStorage.getItem("refreshtoken"));
         if (req.status !== 200) {
            Notifications.sendNotification("offline", MessageType.INFO);
            throw new Error("Offline")
         }
         let res = await req.json();
         if (res.error) {
            console.log("Refresh token invalid, forward to login")
            localStorage.removeItem("refreshtoken");
            this.login()
            throw new Error("Need login!")
         } else {
            return res.token
         }
      } finally {
         lock.release()
      }
   }

   async Logout() {
      localStorage.removeItem("refreshtoken");
      window.location.reload();
   }

   async sync() {
      const lock = await this.syncLock.getLock()
      const log = (...message: any[]) => {
         console.log("[SYNC]: ", ...message)
      }

      this.syncObservableServer.send(true);
      log("Start")
      try {
         log("Fetching");
         let [remotes, locals, oplogs] = await Promise.all([this._secureFile.list(), this.noteDB.getAll(), this.oplogDB.getAll()]);
         log("Fetched");
         // Create sync pairs (remote & local)
         log("Building pairs");
         let pairs: { local: DBNote, remote: IFile, id: string, oplog: OpLog[] }[] = [];
         remotes.map(r => {
            let lIdx = locals.findIndex(e => e._id === r._id);
            let l: DBNote = undefined;
            if (lIdx >= 0) {
               l = locals[lIdx];
               locals.splice(lIdx, 1);
            }

            let oIdx = oplogs.findIndex(e => e.id === r._id);
            let oplog: OpLog[];
            if (oIdx >= 0) {
               oplog = oplogs[oIdx].logs;
               oplogs.splice(oIdx, 1);
            }

            pairs.push({
               remote: r,
               local: l,
               oplog,
               id: r._id
            })
         })

         locals.forEach(l => {
            let oIdx = oplogs.findIndex(e => e.id === l._id);
            let oplog: OpLog[] = undefined;
            if (oIdx >= 0) {
               oplog = oplogs[oIdx].logs;
               if (oplog.length <= 0) oplog = undefined;
               oplogs.splice(oIdx, 1);
            }

            pairs.push({
               remote: undefined,
               local: l,
               oplog,
               id: l._id
            })
         })

         oplogs.forEach(oplog => {
            if (!oplog) return;
            if (oplog.logs.length > 0)
               pairs.push({
                  remote: undefined,
                  local: undefined,
                  oplog: oplog.logs,
                  id: oplog.id
               })
         })

         log("Pairs builded");

         let stats = {
            remote_change: 0,
            remote_delete: 0,
            remote_create: 0,
            local_change: 0,
            local_delete: 0,
            do_nothing: 0,
            error: 0
         }

         log("Start inspection");
         for (let { local, remote, oplog, id } of pairs) {
            const apply = async (old = false) => {
               log("Apply OPLOG to", id);
               for (let op of oplog) {
                  switch (op.type) {
                     case OpLogType.CHANGE:
                        log(id, "REMOTE CHANGE");
                        stats.remote_change++;
                        await this._secureFile.update(id, op.values.value, b64.encode(op.values.preview), op.date, old);
                        break;
                     case OpLogType.DELETE:
                        log(id, "REMOTE DELETE");
                        stats.remote_delete++;
                        if (old) break; // if the deletion is old, just ignore
                        await this._secureFile.delete(id)
                        break;
                     case OpLogType.CREATE:
                        log(id, "REMOTE CREATE");
                        stats.remote_create++;
                        await this._secureFile.create(
                           "",
                           op.values.value,
                           "binary",
                           local.folder,
                           b64.encode(op.values.preview),
                           id,
                           op.date
                        );
                        break;
                  }
               }
            }

            const localChange = (id: string) => {
               //TODO implement
            }

            const create = async () => {
               log(id, "LOCAL CREATAE/UPDATE");
               stats.local_change++;
               let value = await this._secureFile.get(id);
               let note: DBNote = {
                  _id: remote._id,
                  folder: remote.folder,
                  preview: b64.decode(remote.active.preview),
                  time: remote.active.time,
                  __value: new Uint8Array(value)
               }
               await this.noteDB.set(id, note);
               localChange(id);
            }

            try {
               // log(id, "LRO: ", !!local, !!remote, !!oplog)
               if (remote && !oplog) {
                  if (local) {
                     let old = remote.active.time.valueOf() > local.time.valueOf();
                     if (old)
                        await create()
                     else {
                        stats.do_nothing++;
                        log(id, "DO NOTHING");
                     }
                  } else {
                     await create()
                  }
               } else if (!remote && local && !oplog) { // No local changes, but remote deleted
                  log("LOCAL DELETE");
                  stats.local_delete++;
                  await this.noteDB.delete(id);
                  localChange(id);
               } else if (!remote && oplog) { // Remote does not exist, but oplog, just apply all changes including possible delete
                  await apply()
               } else if (remote && oplog) {
                  let last = oplog[oplog.length - 1]
                  let old = remote.active.time.valueOf() > last.date.valueOf();

                  if (old)
                     await create() // Will recreate local entry
                  await apply(old) // Will apply changes to remote
               } else {
                  log(id, "DO NOTHING");
                  stats.do_nothing++;
               }
            } catch (err) {
               console.error(err);
               stats.error++;
               Notifications.sendNotification("Error syncing: " + id, MessageType.ERROR);
            }
            await this.oplogDB.delete(id);
         }
         log("Stats", stats);
         this.syncedObservableServer.send((await this.oplogDB.getAll()).length <= 0)
      } finally {
         log("Finished")
         lock.release()
         this.syncObservableServer.send(false);
      }
   }

   public forgetVaultKey(vault_id: string) {
      this.vaultKeys.delete(vault_id);
      localStorage.removeItem("vault_" + vault_id);
   }

   public getVaultKey(vault_id: string) {
      let key = this.vaultKeys.get(vault_id);
      if (!key) {
         let lsk = localStorage.getItem("vault_" + vault_id);
         if (lsk) {
            key = b64.decode(lsk);
            this.vaultKeys.set(vault_id, key);
         }
      }
      return key;
   }

   public saveVaultKey(vault_id: string, key: Uint8Array, permanent?: boolean) {
      this.vaultKeys.set(vault_id, key);
      if (permanent) {
         localStorage.setItem("vault_" + vault_id, b64.encode(key));
      }
   }

   public getVaults(): Promise<VaultList> {
      return this.noteDB.getAll()
         .then(notes => notes
            .filter(e => Decoder.decode(e.preview) === "__VAULT__")
            .map(e => {
               let value = e.__value;
               let encrypted = false;
               if (this.decrypt(value) !== "__BASELINE__") encrypted = true;
               return { name: e.folder, encrypted, id: e._id }
            }));
   }

   public async createVault(name: string, key?: Uint8Array) {
      let vault: DBNote = {
         __value: this.encrypt("__BASELINE__", key),
         _id: uuidv4(),
         folder: name,
         preview: Encoder.encode("__VAULT__"),
         time: new Date()
      }
      let tx = this.database.transaction();
      await Promise.all([
         this.addop(vault._id, OpLogType.CREATE, {
            value: vault.__value,
            preview: vault.preview
         }, vault.time, tx),
         this.noteDB.set(vault._id, vault)
      ]);
   }

   public async getVault(vault_id: string, key?: Uint8Array): Promise<IVault> {
      let vault = await this.noteDB.get(vault_id);
      if (!vault) throw new Error("Vault not found!");
      if (this.decrypt(vault.__value, key) !== "__BASELINE__") throw new Error("Invalid password!");
      return new NotesProvider.Vault(vault, key)
   }

   public async deleteVault(vault_id: string) {
      let vault = await this.noteDB.get(vault_id);
      if (!vault) throw new Error("Vault not found!");
      let v = new NotesProvider.Vault(vault);
      await Promise.all((await v.getAllNotes()).map(note => this.delete(note._id)));
      await this.delete(v.id); // This can also delete a vault
   }

   public passwordToKey(password: string) {
      return new Uint8Array(sha256.arrayBuffer(password + config.client_id))
   }

   private _encrypt(value: Uint8Array, key?: Uint8Array): Uint8Array {
      if (!key) return value;
      var aesCtr = new aesjs.ModeOfOperation.ctr(key);
      var encryptedBytes = aesCtr.encrypt(value);
      return new Uint8Array(encryptedBytes);
   }

   private encrypt(value: string, key?: Uint8Array): Uint8Array {
      let msg = this._encrypt(Encoder.encode(value), key)
      return new Uint8Array(this._encrypt(msg, this.generalEncryption))
   }

   private _decrypt(value: ArrayBuffer, key?: Uint8Array): Uint8Array {
      if (!key) return new Uint8Array(value);
      var aesCtr = new aesjs.ModeOfOperation.ctr(key);
      var decryptedBytes = aesCtr.decrypt(value);
      return new Uint8Array(decryptedBytes)
   }

   private decrypt(value: ArrayBuffer, key?: Uint8Array): string {
      let msg = this._decrypt(value, key)
      return Decoder.decode(this._decrypt(msg, this.generalEncryption))
   }

   async addop(note_id: string, type: OpLogType, values: { value: Uint8Array, preview: Uint8Array }, date: Date, transaction?: Transaction) {
      let tx = transaction || this.oplogDB.transaction();
      let oplog = await this.oplogDB.get(note_id, tx);
      if (!oplog) oplog = { logs: [], id: note_id };
      oplog.logs.push({
         date: date,
         type,
         values
      })
      this.syncedObservableServer.send(false);
      await this.oplogDB.set(note_id, oplog, tx);
   }

   async delete(id: string) {
      let lock = await this.syncLock.getLock();
      let tx = this.database.transaction(this.oplogDB, this.noteDB)
      await Promise.all([
         this.addop(id, OpLogType.DELETE, null, new Date(), tx),
         this.noteDB.delete(id, tx)
      ])
      lock.release();
   }

   static Vault = class implements IVault {
      id: string;
      name: string;
      encrypted: boolean = false;
      constructor(private vault: Note, private key?: Uint8Array) {
         if (key) this.encrypted = true;
         this.id = vault._id;
         this.name = vault.folder;
      }

      private encrypt(data: string) {
         return Notes.encrypt(data, this.key);
      }

      private decrypt(data: ArrayBuffer) {
         return Notes.decrypt(data, this.key);
      }

      async getAllNotes() {
         return Notes.noteDB.getAll()
            .then(all => all.filter(e => e.folder === this.vault._id)
               .map<BaseNote>(e => {
                  let new_note = clonedeep(<Note>e) as BaseNote
                  delete (<any>new_note).__value
                  new_note.preview = this.decrypt(e.preview)
                  return new_note;
               }));
      }

      async searchNote(term: string) {
         let all = await this.getAllNotes();
         return all.filter(e => e.preview.indexOf(term) >= 0)
      }

      newNote(): ViewNote {
         return {
            _id: uuidv4(),
            folder: this.vault._id,
            time: new Date(),
            __value: "",
            preview: ""
         }
      }

      async saveNote(note: ViewNote, date = new Date()) {
         let lock = await Notes.syncLock.getLock();
         const tx = Notes.database.transaction(Notes.noteDB, Notes.oplogDB);
         let old_note = await Notes.noteDB.get(note._id, tx);

         let new_note = clonedeep(<Note>note) as DBNote;
         new_note.__value = this.encrypt(note.__value)
         let [title, preview] = note.__value.split("\n");
         if (preview) preview = "\n" + preview;
         else preview = ""
         new_note.preview = this.encrypt((title + preview).substr(0, 128))
         new_note.time = date;

         await Promise.all([
            Notes.addop(note._id, !old_note ? OpLogType.CREATE : OpLogType.CHANGE, {
               value: new_note.__value,
               preview: new_note.preview
            }, date, tx),
            Notes.noteDB.set(note._id, new_note, tx)
         ])
         lock.release();
      }

      async getNote(id: string): Promise<ViewNote> {
         let note = await Notes.noteDB.get(id);
         if (!note) return undefined;
         let new_note = clonedeep(<Note>note) as ViewNote;
         new_note.__value = this.decrypt(note.__value);
         return new_note;
      }

      deleteNote(id: string) {
         return Notes.delete(id);
      }
   }
}

const Notes = new NotesProvider()
export default Notes;

(<any>window).api = Notes