import chai, { assert, expect } from 'chai';
import chaiBytes from 'chai-bytes';
import { bufferByteSize, LiteHashDRBG } from '../ts/util/LiteHashDRBG';
import { RandUtil } from '../ts/util/RandUtil';
import { convertBytesLikeToArrayBuffer } from '../ts/util/convertBytesLikeToArrayBuffer';
import { convertBytesLikeToUint8Array as toBytes } from '../ts/util/convertBytesLikeToUint8Array';
import _ from 'lodash';

chai.use(chaiBytes);

type Bytes = ArrayBuffer | DataView | Uint8Array;
type MaybeBytes = Bytes | string;

function fillBlock(body: MaybeBytes, filler: MaybeBytes = '\0', length = bufferByteSize): Uint8Array {
    const u8Body = toBytes(body);
    const u8Filler = toBytes(filler, false);

    if (u8Filler.byteLength < 1) {
        throw new Error('filler must have length');
    }

    const buffer = new Uint8Array(length);
    buffer.set(u8Body, 0);
    let bufferIdx = u8Body.byteLength;

    while (bufferIdx + u8Filler.byteLength < length) {
        buffer.set(u8Filler, bufferIdx);
        bufferIdx += u8Filler.byteLength;
    }

    if (bufferIdx < length) {
        const slice = new Uint8Array(u8Filler.buffer, u8Filler.byteOffset, length - bufferIdx);
        buffer.set(slice, bufferIdx);
    }

    return buffer;
}

class DummyBlockRNG extends LiteHashDRBG {
    private repeatBlockCnt: number;
    private repeatBlock: ArrayBuffer[];

    public constructor(repeatBlock: MaybeBytes[], stateIdx = 0) {
        super('x');

        this.repeatBlock = [];
        for (const rawBlock of repeatBlock) {
            const block = convertBytesLikeToArrayBuffer(rawBlock);
            if (block.byteLength !== bufferByteSize) {
                throw new Error;
            }
            this.repeatBlock.push(block);
        }
        this.repeatBlockCnt = this.repeatBlock.length;
        this.stateIdx = stateIdx;
        this.bufferIdx = 0;
        this.genNextBlock();
    }

    protected genNextBlock() {
        if (!this.repeatBlock) {
            return;
        }
        this.buffer = this.repeatBlock[this.stateIdx];
        this.bufferIdx = 0;
        this.stateIdx = (this.stateIdx + 1) % this.repeatBlockCnt;
    }
}

const fixedKey = 'HelloWorld';


describe('RNGtestDummy', () => {
    const rng = new DummyBlockRNG([
        fillBlock('', "\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff")
    ]);

    it('BasicConvert', () => {
        assert.equal(toBytes("\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff", false).length, 16);
    });
    it('SimpleByte', () => {
        assert.equalBytes(toBytes("\x00", false), rng.nextBytes(1), 'b1');
        assert.equalBytes(toBytes("\x11\x22", false), rng.nextBytes(2), 'b2');
        assert.equalBytes(toBytes("\x33\x44\x55", false), rng.nextBytes(3), 'b3');
        assert.equalBytes(toBytes("\x66\x77\x88\x99", false), rng.nextBytes(4), 'b4');
    });

    it('OverflowBlock', () => {
        for (const idx in _.range(16)) {
            assert.equalBytes(
                toBytes("\xaa\xbb\xcc\xdd\xee\xff\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99", false),
                rng.nextBytes(16)
            );
        }
    });

    it('MultiBlock', () => {
        assert.equalBytes(
            fillBlock('', "\xaa\xbb\xcc\xdd\xee\xff\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99", bufferByteSize * 2),
            rng.nextBytes(bufferByteSize * 2)
        );
    });

    it('bitTest', () => {
        assert.equalBytes(toBytes("\x00", false), rng.nextBits(1)); //aa
        assert.equalBytes(toBytes("\x01", false), rng.nextBits(1)); //bb
        assert.equalBytes(toBytes("\xcc", false), rng.nextBits(8)); //cc
        assert.equalBytes(toBytes("\xdd\x02", false), rng.nextBits(10)); //ddee
        assert.equalBytes(toBytes("\x7f", false), rng.nextBits(7)); //ff
        assert.equalBytes(toBytes("\x00\x11\x22\x33\x44\x55\x06", false), rng.nextBits(53));
    });

    it('int', () => {
        assert.equal(0x77, rng.nextInt(0xff));
        assert.equal(0x9988, rng.nextInt((1 << 16) - 1));
        assert.equal(0xddccbbaa, rng.nextInt(0xffffffff));
        assert.equal(0x0433221100ffee, rng.nextInt());
        assert.equal(0x05, rng.nextInt(0x0f)); //55
        assert.equal(0x06, rng.nextInt(0x12)); //66
        assert.equal(0x08, rng.nextInt(99)); //77(119 -> 7bit) -> 88(136 -> 8bit -> 8)
        assert.equal(0x99, rng.nextInt(0x99)); //99
        assert.equal(0xaa, rng.nextInt(0xaa)); //aa (fit Max)
    });

    it('float', () => {
        const floatMax = 2 ** 53;
        const fa = rng.nextFloat1();
        assert.equal(0x1100ffeeddccbb / floatMax, fa);
        assert.isTrue(0.5313720384 > fa);
        assert.isTrue(0.5313720383 < fa);
        const fb = rng.nextFloat1();
        assert.equal(0x08776655443322 / floatMax, fb);
    });
});

describe('RNGexpectedError', ()=>{
    const rng = new LiteHashDRBG(fixedKey);
    it('nextBits0', ()=>{
        assert.throw(()=>rng.nextBits(0));
    });
    it('nextBits-1', ()=>{
        assert.throw(()=>rng.nextBits(-1));
    });

    it('nextBytes0', ()=>{
        assert.throw(()=>rng.nextBytes(0));
    });
    it('nextBytes-1', ()=>{
        assert.throw(()=>rng.nextBytes(-1));
    });

    const randUtil = new RandUtil(rng);
    it('utilEmptyChoice', ()=>{
        assert.throw(()=>randUtil.choice([]));
    });
    it('utilEmptyChoiceUsingWeight', ()=>{
        assert.throw(()=>randUtil.choiceUsingWeight({}));
    });
    it('utilEmptyChoiceUsingWeightPair', ()=>{
        assert.throw(()=>randUtil.choiceUsingWeightPair([]));
    });
});

describe('RNGAcceptable', ()=>{
    const rng = new LiteHashDRBG(fixedKey);
    it('RNG', ()=>{
        rng.nextInt(0);
        rng.nextInt(2 ** 53 - 1);
        rng.nextBytes(65);
        rng.nextBits(512);
    });

    const randUtil = new RandUtil(rng);
    it('RandUtil', ()=>{
        randUtil.choice([0, 0, 0]);
        randUtil.choiceUsingWeight({
            0: 0,
            1: -1
        });
        randUtil.choiceUsingWeightPair([
            [0, 0],
            [1, 0],
            [2, -2]
        ]);
        randUtil.nextBool(1.1);
        randUtil.nextBool(-0.1);
        randUtil.shuffle([]);
        randUtil.shuffle([1]);
        randUtil.nextRange(0, 0);
        randUtil.nextRangeInt(0, 0);
        randUtil.nextRange(1, -1);
        randUtil.nextRangeInt(1, -1);
    })
});