import {
    Value,
    Dictionary,
    decode, decodeWithAnnotations, encode, canonicalEncode,
    DecodeError, ShortPacket,
    Bytes, Record,
    annotate,
    strip, peel,
    preserves,
    stringify,
    fromJS,
    Constants,
    Encoder,
    GenericEmbedded,
    EncoderState,
    EmbeddedType,
    DecoderState,
    Decoder,
    Embedded,
    embed,
    genericEmbeddedTypeDecode,
    genericEmbeddedTypeEncode,
    parse,
} from '../src/index';
const { Tag } = Constants;
import './test-utils';

import * as fs from 'fs';

const _discard = Symbol.for('discard');
const _capture = Symbol.for('capture');
const _observe = Symbol.for('observe');
const Discard = Record.makeConstructor<{}, GenericEmbedded>()(_discard, []);
const Capture = Record.makeConstructor<{pattern: Value<GenericEmbedded>}, GenericEmbedded>()(_capture, ['pattern']);
const Observe = Record.makeConstructor<{pattern: Value<GenericEmbedded>}, GenericEmbedded>()(_observe, ['pattern']);

describe('record constructors', () => {
    it('should have constructorInfo', () => {
        expect(Discard.constructorInfo.label).toEqual(Symbol.for('discard'));
        expect(Capture.constructorInfo.label).toEqual(Symbol.for('capture'));
        expect(Observe.constructorInfo.label).toEqual(Symbol.for('observe'));
        expect(Discard.constructorInfo.arity).toEqual(0);
        expect(Capture.constructorInfo.arity).toEqual(1);
        expect(Observe.constructorInfo.arity).toEqual(1);
    });
})

describe('RecordConstructorInfo', () => {
    const C1 = Record.makeConstructor<{x: number, y: number}>()([1], ['x', 'y']);
    const C2 = Record.makeConstructor<{z: number, w: number}>()([1], ['z', 'w']);
    it('instance comparison should ignore embedded and fieldname differences', () => {
        expect(C1(9,9)).is(C2(9,9));
        expect(C1(9,9)).not.is(C2(9,8));
    });
    it('comparison based on embedded equality should not work', () => {
        expect(C1.constructorInfo).not.toBe(C2.constructorInfo);
    });
    it('comparison based on .equals should work', () => {
        expect(C1.constructorInfo).toEqual(C2.constructorInfo);
    });
});

describe('records', () => {
    it('should have correct getConstructorInfo', () => {
        expect(Record.constructorInfo(Discard())).toEqual(Discard.constructorInfo);
        expect(Record.constructorInfo(Capture(Discard()))).toEqual(Capture.constructorInfo);
        expect(Record.constructorInfo(Observe(Capture(Discard())))).toEqual(Observe.constructorInfo);
    });
});

describe('parsing from subarray', () => {
    it('should maintain alignment of nextbytes', () => {
        const u = Uint8Array.of(1, 1, 1, 1, 0xb1, 0x03, 0x33, 0x33, 0x33);
        const bs = Bytes.from(u.subarray(4));
        expect(decode(bs)).is("333");
    });
});

describe('reusing buffer space', () => {
    it('should be done safely, even with nested dictionaries', () => {
        expect(canonicalEncode(fromJS(['aaa', Dictionary.fromJS({a: 1}), 'zzz'])).toHex()).is(
            `b5
               b103616161
               b7
                 b10161 b00101
               84
               b1037a7a7a
             84`.replace(/\s+/g, ''));
    });
});

describe('encoding and decoding embeddeds', () => {
    class LookasideEmbeddedType implements EmbeddedType<object> {
        readonly objects: object[];

        constructor(objects: object[]) {
            this.objects = objects;
        }

        decode(d: DecoderState): object {
            return this.fromValue(new Decoder<GenericEmbedded>(d).next());
        }

        encode(e: EncoderState, v: object): void {
            new Encoder(e).push(this.toValue(v));
        }

        equals(a: object, b: object): boolean {
            return Object.is(a, b);
        }

        fromValue(v: Value<GenericEmbedded>): object {
            if (typeof v !== 'number' || v < 0 || v >= this.objects.length) {
                throw new Error("Unknown embedded target");
            }
            return this.objects[v];
        }

        toValue(v: object): number {
            let i = this.objects.indexOf(v);
            if (i !== -1) return i;
            this.objects.push(v);
            return this.objects.length - 1;
        }
    }

    it('should encode using embeddedId when no function has been supplied', () => {
        const A1 = embed({a: 1});
        const A2 = embed({a: 1});
        const bs1 = canonicalEncode(A1);
        const bs2 = canonicalEncode(A2);
        const bs3 = canonicalEncode(A1);
        expect(bs1.get(0)).toBe(Tag.Embedded);
        expect(bs2.get(0)).toBe(Tag.Embedded);
        expect(bs3.get(0)).toBe(Tag.Embedded);
        // Can't really check the value assigned to the object. But we
        // can check that it's different to a similar object!
        expect(bs1).not.is(bs2);
        expect(bs1).is(bs3);
    });
    it('should refuse to decode embeddeds when no function has been supplied', () => {
        expect(() => decode(Bytes.from([Tag.Embedded, Tag.False])))
            .toThrow("Embeddeds not permitted at this point in Preserves document");
    });
    it('should encode properly', () => {
        const objects: object[] = [];
        const pt = new LookasideEmbeddedType(objects);
        const A = embed({a: 1});
        const B = embed({b: 2});
        expect(encode([A, B], { embeddedEncode: pt })).is(
            Bytes.from([Tag.Sequence,
                        Tag.Embedded, Tag.SignedInteger, 0,
                        Tag.Embedded, Tag.SignedInteger, 1, 1,
                        Tag.End]));
        expect(objects).toEqual([A.embeddedValue, B.embeddedValue]);
    });
    it('should decode properly', () => {
        const objects: object[] = [];
        const pt = new LookasideEmbeddedType(objects);
        const X: Embedded<object> = embed({x: 123});
        const Y: Embedded<object> = embed({y: 456});
        objects.push(X.embeddedValue);
        objects.push(Y.embeddedValue);
        expect(decode(Bytes.from([
            Tag.Sequence,
            Tag.Embedded, Tag.SignedInteger, 0,
            Tag.Embedded, Tag.SignedInteger, 1, 1,
            Tag.End
        ]), { embeddedDecode: pt })).is([X, Y]);
    });
    it('should store embeddeds embedded in map keys correctly', () => {
        const A1a = {a: 1};
        const A1: Embedded<object> = embed(A1a);
        const A2: Embedded<object> = embed({a: 1});
        const m = new Dictionary<object, number>();
        m.set([A1], 1);
        m.set([A2], 2);
        expect(m.get(A1)).toBeUndefined();
        expect(m.get([A1])).toBe(1);
        expect(m.get([A2])).toBe(2);
        expect(m.get([embed({a: 1})])).toBeUndefined();
        A1a.a = 3;
        expect(m.get([A1])).toBe(1);
    });
});

describe('common test suite', () => {
    const samples_bin = fs.readFileSync(__dirname + '/../../../../../tests/samples.bin');
    const samples = decodeWithAnnotations(samples_bin, { embeddedDecode: genericEmbeddedTypeDecode });

    const TestCases = Record.makeConstructor<{
        cases: Dictionary<GenericEmbedded>
    }>()(Symbol.for('TestCases'), ['cases']);
    type TestCases = ReturnType<typeof TestCases>;

    function encodeBinary(v: Value<GenericEmbedded>): Bytes {
        return encode(v, { canonical: true, embeddedEncode: genericEmbeddedTypeEncode });
    }
    function looseEncodeBinary(v: Value<GenericEmbedded>): Bytes {
        return encode(v, { canonical: false, includeAnnotations: true, embeddedEncode: genericEmbeddedTypeEncode });
    }
    function annotatedBinary(v: Value<GenericEmbedded>): Bytes {
        return encode(v, { canonical: true, includeAnnotations: true, embeddedEncode: genericEmbeddedTypeEncode });
    }
    function decodeBinary(bs: Bytes): Value<GenericEmbedded> {
        return decode(bs, { includeAnnotations: true, embeddedDecode: genericEmbeddedTypeDecode  });
    }
    function encodeText(v: Value<GenericEmbedded>): string {
        return stringify(v, { includeAnnotations: true, embeddedWrite: genericEmbeddedTypeEncode });
    }
    function decodeText(s: string): Value<GenericEmbedded> {
        return parse(s, { includeAnnotations: true, embeddedDecode: genericEmbeddedTypeDecode });
    }

    type Variety = 'normal' | 'nondeterministic';

    function runTestCase(variety: Variety,
                         tName: string,
                         binary: Bytes,
                         annotatedValue: Value<GenericEmbedded>)
    {
        describe(tName, () => {
            const stripped = strip(annotatedValue);
            it('should round-trip, canonically', () =>
                expect(decodeBinary(encodeBinary(annotatedValue))).is(stripped));
            it('should go back, stripped', () =>
                expect(strip(decodeBinary(binary))).is(stripped));
            it('should go back', () =>
                expect(decodeBinary(binary)).is(annotatedValue));
            it('should round-trip, with annotations', () =>
                expect(decodeBinary(annotatedBinary(annotatedValue))).is(annotatedValue));
            it('should round-trip as text, stripped', () =>
                expect(decodeText(encodeText(stripped))).is(stripped));
            it('should round-trip as text, with annotations', () =>
                expect(decodeText(encodeText(annotatedValue))).is(annotatedValue));
            it('should go forward', () =>
                expect(annotatedBinary(annotatedValue)).is(binary));
            if (variety === 'normal') {
                it('should go forward, loosely', () =>
                    expect(looseEncodeBinary(annotatedValue)).is(binary));
            }
        });
    }

    const tests = (peel(TestCases._.cases(peel(samples) as TestCases)) as
                   Dictionary<GenericEmbedded>);
    tests.forEach((t0: Value<GenericEmbedded>, tName0: Value<GenericEmbedded>) => {
        const tName = Symbol.keyFor(strip(tName0) as symbol)!;
        const t = peel(t0) as Record<symbol, any, GenericEmbedded>;
        switch (t.label) {
            case Symbol.for('Test'):
                runTestCase('normal', tName, strip(t[0]) as Bytes, t[1]);
                break;
            case Symbol.for('NondeterministicTest'):
                runTestCase('nondeterministic', tName, strip(t[0]) as Bytes, t[1]);
                break;
            case Symbol.for('DecodeError'):
                describe(tName, () => {
                    it('should fail with DecodeError', () => {
                        expect(() => decodeBinary(strip(t[0]) as Bytes))
                            .toThrowFilter(e =>
                                DecodeError.isDecodeError(e) &&
                                !ShortPacket.isShortPacket(e));
                    });
                });
                break;
            case Symbol.for('DecodeEOF'): // fall through
            case Symbol.for('DecodeShort'):
                describe(tName, () => {
                    it('should fail with ShortPacket', () => {
                        expect(() => decodeBinary(strip(t[0]) as Bytes))
                            .toThrowFilter(e => ShortPacket.isShortPacket(e));
                    });
                });
                break;
            case Symbol.for('ParseError'):
                describe(tName, () => {
                    it('should fail with DecodeError', () => {
                        expect(() => parse(strip(t[0]) as string))
                            .toThrowFilter(e =>
                                DecodeError.isDecodeError(e) &&
                                !ShortPacket.isShortPacket(e));
                    });
                });
                break;
            case Symbol.for('ParseEOF'):
            case Symbol.for('ParseShort'):
                describe(tName, () => {
                    it('should fail with ShortPacket', () => {
                        expect(() => parse(strip(t[0]) as string))
                            .toThrowFilter(e => ShortPacket.isShortPacket(e));
                    });
                });
                break;
            default:{
                const e = new Error(preserves`Unsupported test kind ${t}`);
                console.error(e);
                throw e;
            }
        }
    });
});