'use strict';

var common = require('../common');

var assert = require('assert');

var L = require('_linklist');

var list = { name: 'list' };

var A = { name: 'A' };

var B = { name: 'B' };

var C = { name: 'C' };

var D = { name: 'D' };

L.init(list);

L.init(A);

L.init(B);

L.init(C);

L.init(D);

assert.ok(L.isEmpty(list));

assert.equal(null, L.peek(list));

L.append(list, A);

// list -> A

assert.equal(A, L.peek(list));

L.append(list, B);

// list -> A -> B

assert.equal(A, L.peek(list));

L.append(list, C);

// list -> A -> B -> C

assert.equal(A, L.peek(list));

L.append(list, D);

// list -> A -> B -> C -> D

assert.equal(A, L.peek(list));

var x = L.shift(list);

assert.equal(A, x);

// list -> B -> C -> D

assert.equal(B, L.peek(list));

x = L.shift(list);

assert.equal(B, x);

// list -> C -> D

assert.equal(C, L.peek(list));

// B is already removed, so removing it again shouldn't hurt.

L.remove(B);

// list -> C -> D

assert.equal(C, L.peek(list));

// Put B back on the list

L.append(list, B);

// list -> C -> D -> B

assert.equal(C, L.peek(list));

L.remove(C);

// list -> D -> B

assert.equal(D, L.peek(list));

L.remove(B);

// list -> D

assert.equal(D, L.peek(list));

L.remove(D);

// list

assert.equal(null, L.peek(list));

assert.ok(L.isEmpty(list));

L.append(list, D);

// list -> D

assert.equal(D, L.peek(list));

L.append(list, C);

L.append(list, B);

L.append(list, A);

// list -> D -> C -> B -> A

// Append should REMOVE C from the list and append it to the end.

L.append(list, C);

// list -> D -> B -> A -> C

assert.equal(D, L.shift(list));

// list -> B -> A -> C

assert.equal(B, L.peek(list));

assert.equal(B, L.shift(list));

// list -> A -> C

assert.equal(A, L.peek(list));

assert.equal(A, L.shift(list));

// list -> C

assert.equal(C, L.peek(list));

assert.equal(C, L.shift(list));

// list

assert.ok(L.isEmpty(list));