import { GenericPointer, PointerType, PointerTypeDecode, PointerTypeEncode } from "./pointer";
import { Encoder, EncoderState, identityPointerTypeEncode } from "./encoder";
import { genericPointerTypeDecode } from "./reader";
import { Value } from "./values";
import { DecoderState, neverPointerTypeDecode } from "./decoder";

export const genericPointerTypeEncode: PointerTypeEncode<GenericPointer> = {
    encode(s: EncoderState, v: GenericPointer): void {
        new Encoder(s, this).push(v.generic);
    },

    toValue(v: GenericPointer): Value<GenericPointer> {
        return v.generic;
    }
};

export const genericPointerType: PointerType<GenericPointer> =
    Object.assign({},
                  genericPointerTypeDecode,
                  genericPointerTypeEncode);

export const neverPointerTypeEncode: PointerTypeEncode<never> = {
    encode(_s: EncoderState, _v: never): void {
        throw new Error("Pointers not permitted encoding Preserves document");
    },

    toValue(_v: never): Value<GenericPointer> {
        throw new Error("Pointers not permitted encoding Preserves document");
    }
};

export const neverPointerType: PointerType<never> =
    Object.assign({},
                  neverPointerTypeDecode,
                  neverPointerTypeEncode);

export const identityPointerTypeDecode: PointerTypeDecode<any> = {
    decode(_s: DecoderState): any {
        throw new Error("Cannot decode identityPointerType");
    },

    fromValue(_v: Value<GenericPointer>): any {
        throw new Error("Cannot decode identityPointerType");
    },
};

export const identityPointerType: PointerType<any> =
    Object.assign({},
                  identityPointerTypeDecode,
                  identityPointerTypeEncode);