import {HTTP_INTERCEPTORS, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest, HttpResponse} from '@angular/common/http';
import {Injectable} from '@angular/core';
import {Observable, of, throwError} from 'rxjs';
import {delay, dematerialize, materialize, mergeMap} from 'rxjs/operators';

const accounts = [
  {id: 1, name: 'John Doe', phone: '+25412345678', address: '0xc86ff893ac40d3950b4d5f94a9b837258b0a9865', type: 'user', created: '08/16/2020', balance: '12987', failedPinAttempts: 1, status: 'approved', bio: 'Bodaboda', category: 'transport', gender: 'male', location: 'Bofu', token: 'RSV', referrer: 'Jane Buck'},
  {id: 2, name: 'Jane Buck', phone: '+25412341234', address: '0xc86ff893ac40d3950b4d5f94a9b837258b0a9865', type: 'vendor', created: '04/02/2020', balance: '56281', failedPinAttempts: 0, status: 'approved', bio: 'Groceries', category: 'food/water', gender: 'female', location: 'Lindi', token: 'ERN', referrer: ''},
  {id: 3, name: 'Mc Donald', phone: '+25498765432', address: '0xc86ff893ac40d3950b4d5f94a9b837258b0a9865', type: 'group', created: '11/16/2020', balance: '450', failedPinAttempts: 2, status: 'unapproved', bio: 'Food', category: 'food/water', gender: 'male', location: 'Miyani', token: 'RSV', referrer: 'Hera Cles'},
  {id: 4, name: 'Hera Cles', phone: '+25498769876', address: '0xc86ff893ac40d3950b4d5f94a9b837258b0a9865', type: 'user', created: '05/28/2020', balance: '5621', failedPinAttempts: 3, status: 'approved', bio: 'Shop', category: 'shop', gender: 'female', location: 'Kayaba', token: 'BRT', referrer: 'Jane Buck'},
  {id: 5, name: 'Silver Fia', phone: '+25462518374', address: '0xc86ff893ac40d3950b4d5f94a9b837258b0a9865', type: 'tokenAgent', created: '10/10/2020', balance: '817', failedPinAttempts: 0, status: 'unapproved', bio: 'Electronics', category: 'shop', gender: 'male', location: 'Mkanyeni', token: 'RSV', referrer: 'John Doe'},
];

const actions = [
  { id: 1, user: 'Tom', role: 'enroller', action: 'Disburse RSV 100', approval: false },
  { id: 2, user: 'Christine', role: 'admin', action: 'Change user phone number', approval: true },
  { id: 3, user: 'Will', role: 'superadmin', action: 'Reclaim RSV 1000', approval: true },
  { id: 4, user: 'Vivian', role: 'enroller', action: 'Complete user profile', approval: true },
  { id: 5, user: 'Jack', role: 'enroller', action: 'Reclaim RSV 200', approval: false },
  { id: 6, user: 'Patience', role: 'enroller', action: 'Change user information', approval: false }
];

const histories = [
  { id: 1, userId: 3, userName: 'Mc Donald', action: 'Receive RSV 100', staff: 'Tom', timestamp: Date.now() },
  { id: 2, userId: 5, userName: 'Silver Fia', action: 'Change phone number from +25412345678 to +25498765432', staff: 'Christine', timestamp: Date.now()},
  { id: 3, userId: 4, userName: 'Hera Cles', action: 'Completed user profile', staff: 'Vivian', timestamp: Date.now() },
];

const locations: any = [
  { name: 'Kwale',
    districts: [
      { name: 'Kinango',
        locations: [
          { name: 'Bofu', villages: ['Bofu', 'Chidzuvini', 'Mkanyeni']},
          { name: 'Mnyenzeni', villages: ['Miloeni', 'Miyani', 'Mnyenzeni', 'Vikolani', 'Vitangani']}
        ]
      }
    ]
  },
  { name: 'Nairobi',
    districts: [
      { name: 'Dagorreti',
        locations: [
          { name: 'Kawangware', villages: ['Congo']},
        ]
      },
      { name: 'Ngong',
        locations: [
          { name: 'Kibera', villages: ['Kibera', 'Lindi']},
        ]
      },
      { name: 'South B',
        locations: [
          { name: 'Mukuru', villages: ['Kayaba']},
          { name: 'South B', villages: ['South B']},
        ]
      },
    ]
  }
];

const staffMembers = [
  { id: 1, name: 'admin@acme.org', accountType: 'Admin', created: '17/11/2020', status: 'activated'},
  { id: 2, name: 'will@grassecon.org', accountType: 'SuperAdmin', created: '17/11/2020', status: 'activated'},
  { id: 3, name: 'spence@grassecon.org', accountType: 'Enroller', created: '17/11/2020', status: 'activated'},
  { id: 4, name: 'admin@redcross.org', accountType: 'View', created: '17/11/2020', status: 'activated'}
];

const tokens = [
  {name: 'Giftable Reserve', symbol: 'GRZ', address: '0xa686005CE37Dce7738436256982C3903f2E4ea8E', supply: '1000000001000000000000000000', decimals: '18', reserves: {}},
  {name: 'Demo Token', symbol: 'DEMO', address: '0xc80D6aFF8194114c52AEcD84c9f15fd5c8abb187', supply: '99999999999999998976', decimals: '18', reserves: {'0xa686005CE37Dce7738436256982C3903f2E4ea8E': {weight: '1000000', balance: '99999999999999998976'}}, reserveRatio: '1000000', owner: '0x3Da99AAD2D9CA01D131eFc3B17444b832B31Ff4a'},
  {name: 'Foo Token', symbol: 'FOO', address: '0x9ceD86089f7aBB5A97B40eb0E7521e7aa308d354', supply: '1000000000000000001014', decimals: '18', reserves: {'0xa686005CE37Dce7738436256982C3903f2E4ea8E': {weight: '1000000', balance: '1000000000000000001014'}}, reserveRatio: '1000000', owner: '0x3Da99AAD2D9CA01D131eFc3B17444b832B31Ff4a'},
  {name: 'testb', symbol: 'tstb', address: '0xC63cFA91A3BFf41cE31Ff436f67D3ACBC977DB95', supply: '99000', decimals: '18', reserves: {'0xa686005CE37Dce7738436256982C3903f2E4ea8E': {weight: '1000000', balance: '99000'}}, reserveRatio: '1000000', owner: '0x3Da99AAD2D9CA01D131eFc3B17444b832B31Ff4a'},
  {name: 'testa', symbol: 'tsta', address: '0x8fA4101ef19D0a078239d035659e92b278bD083C', supply: '9981', decimals: '18', reserves: {'0xa686005CE37Dce7738436256982C3903f2E4ea8E': {weight: '1000000', balance: '9981'}}, reserveRatio: '1000000', owner: '0x3Da99AAD2D9CA01D131eFc3B17444b832B31Ff4a'},
  {name: 'testc', symbol: 'tstc', address: '0x4A6fA6bc3BfE4C9661bC692D9798425350C9e3D4', supply: '100990', decimals: '18', reserves: {'0xa686005CE37Dce7738436256982C3903f2E4ea8E': {weight: '1000000', balance: '100990'}}, reserveRatio: '1000000', owner: '0x3Da99AAD2D9CA01D131eFc3B17444b832B31Ff4a'}
];

@Injectable()
export class MockBackendInterceptor implements HttpInterceptor {
  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const { url, method, headers, body } = request;

    // wrap in delayed observable to simulate server api call\
    // call materialize and dematerialize to ensure delay even is thrown
    return of(null)
      .pipe(mergeMap(handleRoute))
      .pipe(materialize())
      .pipe(delay(500))
      .pipe(dematerialize());

    function handleRoute(): Observable<any> {
      switch (true) {
        case url.endsWith('/accounts') && method === 'GET':
          return getAccounts();
        case url.match(/\/accounts\/\d+$/) && method === 'GET':
          return getAccountById();
        case url.endsWith('/actions') && method === 'GET':
          return getActions();
        case url.match(/\/actions\/\d+$/) && method === 'GET':
          return getActionById();
        case url.match(/\/actions\/\d+$/) && method === 'POST':
          return approveAction();
        case url.match(/\/history\/\d+$/) && method === 'GET':
          return getHistoryByUser();
        case url.endsWith('/locations') && method === 'GET':
          return getLocations();
        case url.endsWith('/staff') && method === 'GET':
          return getStaff();
        case url.match(/\/staff\/\d+$/) && method === 'GET':
          return getStaffById();
        case url.match(/\/staff\/\d+$/) && method === 'POST' && body.status !== undefined:
          return changeStaffStatus();
        case url.match(/\/staff\/\d+$/) && method === 'POST' && body.accountType !== undefined:
          return changeStaffType();
        case url.endsWith('/tokens') && method === 'GET':
          return getTokens();
        case url.match(/\/tokens\/\w+$/) && method === 'GET':
          return getTokenBySymbol();
        default:
          // pass through any requests not handled above
          return next.handle(request);
      }
    }

    // route functions

    function getAccounts(): Observable<any> {
      return ok(accounts);
    }

    function getAccountById(): Observable<any> {
      const queriedAccount = accounts.find(account => account.id === idFromUrl());
      return ok(queriedAccount);
    }

    function getActions(): Observable<any> {
      return ok(actions);
    }

    function getActionById(): Observable<any> {
      const queriedAction = actions.find(action => action.id === idFromUrl());
      return ok(queriedAction);
    }

    function approveAction(): Observable<any> {
      const queriedAction = actions.find(action => action.id === idFromUrl());
      queriedAction.approval = body.approval;
      const message = `Action approval status set to ${body.approval} successfully!`;
      return ok(message);
    }

    function getHistoryByUser(): Observable<any> {
      const queriedUserHistory = histories.filter(history => history.userId === idFromUrl());
      return ok(queriedUserHistory);
    }

    function getLocations(): Observable<any> {
      return ok(locations);
    }

    function getStaff(): Observable<any> {
      return ok(staffMembers);
    }

    function getStaffById(): Observable<any> {
      const queriedStaff = staffMembers.find(staff => staff.id === idFromUrl());
      return ok(queriedStaff);
    }

    function changeStaffStatus(): Observable<any> {
      const queriedStaff = staffMembers.find(staff => staff.id === idFromUrl());
      queriedStaff.status = body.status;
      const message = `Staff account status changed to ${body.status} successfully!`;
      return ok(message);
    }

    function changeStaffType(): Observable<any> {
      const queriedStaff = staffMembers.find(staff => staff.id === idFromUrl());
      queriedStaff.accountType = body.accountType;
      const message = `Staff account type changed to ${body.accountType} successfully!`;
      return ok(message);
    }

    function getTokens(): Observable<any> {
      return ok(tokens);
    }

    function getTokenBySymbol(): Observable<any> {
      const queriedToken = tokens.find(token => token.symbol === stringFromUrl());
      return ok(queriedToken);
    }

    // helper functions

    function ok(body): Observable<any> {
      return of(new HttpResponse({ status: 200, body }));
    }

    function error(message): Observable<any> {
      return throwError({ status: 400, error: { message } });
    }

    function idFromUrl(): number {
      const urlParts = url.split('/');
      return parseInt(urlParts[urlParts.length - 1], 10);
    }

    function stringFromUrl(): string {
      const urlParts = url.split('/');
      return urlParts[urlParts.length - 1];
    }
  }
}

export const MockBackendProvider = {
  provide: HTTP_INTERCEPTORS,
  useClass: MockBackendInterceptor,
  multi: true
};