import {Buffer} from "buffer";
import {OAD} from "./OAD";
import {ROAD} from "./ROAD";
import {AxdrType} from "../asn1.axdr/AxdrType";
import {ReverseByteArrayInputStream} from "../ReverseByteArrayInputStream";
import {ReverseByteArrayOutputStream} from "../ReverseByteArrayOutputStream";
import {AxdrEnum} from "../asn1.axdr/AxdrEnum";


enum Choice {
    _ERR_NONE_SELECTED = -1,
    OAD = 0,
    ROAD = 1
}

export class CSD implements AxdrType{

    dataCode : Buffer | null = null;
    choice : Choice = Choice._ERR_NONE_SELECTED;
    oad : OAD | null = null;
    road : ROAD | null = null;

    constructor() {

    }

    set_dataCode(dataCode : Buffer){
        this.dataCode = dataCode;
    }

    set_oad(oad : OAD){
        this.resetChoices();
        this.choice = Choice.OAD;
        this.oad = oad;
    }

    set_road(road : ROAD){
        this.resetChoices();
        this.choice = Choice.ROAD;
        this.road = road;
    }

    decode(input: ReverseByteArrayInputStream): number {
        let codeLength = 0;
        let choosen = new AxdrEnum();
        choosen.set_const();

        codeLength += choosen.decode(input);
        this.resetChoices();
        this.choice = choosen.getValue();

        if (this.choice == Choice.OAD) {
            this.oad = new OAD();
            codeLength += this.oad.decode(input);
            return codeLength;
        }

        if (this.choice == Choice.ROAD) {
            this.road = new ROAD();
            codeLength += this.road.decode(input);
            return codeLength;
        }
        throw new Error("Error decoding AxdrChoice: Identifier matched to no item.");
    }

    encode(output: ReverseByteArrayOutputStream): number {
        if (this.dataCode != null) {
            for (let i = this.dataCode.length - 1; i >= 0; i--) {
                output.write(this.dataCode[i]);
            }
            return this.dataCode.length;

        }
        if (this.choice == Choice._ERR_NONE_SELECTED) {
            throw new Error("Error encoding AxdrChoice: No item in choice was selected.");
        }

        let codeLength = 0;

        if (this.choice == Choice.ROAD) {
            codeLength += this.road.encode(output);
            let c = new AxdrEnum();
            c.set_min_max_val(1)
            codeLength += c.encode(output);
            return codeLength;
        }

        if (this.choice == Choice.OAD) {
            codeLength += this.oad.encode(output);
            let c = new AxdrEnum();
            c.set_min_max_val(0)
            codeLength += c.encode(output);
            return codeLength;
        }
        throw new Error("Error encoding AxdrChoice: No item in choice was encoded.");
    }

    getChoiceIndex() : Choice{
        return this.choice;
    }

    encodeAndSave(encodingSizeGuess: number) {
        let revOStream = new ReverseByteArrayOutputStream();
        revOStream.setBufSize(encodingSizeGuess);
        this.encode(revOStream);
        this.dataCode = revOStream.getArray();
    }

    resetChoices() {
        this.choice = Choice._ERR_NONE_SELECTED;
        this.oad = null;
        this.road = null;
    }

    toString(): string {
        if (this.choice == Choice.OAD) {
            if (this.oad != null) {
                return "choice: {oad: " + this.oad + "}";
            } else {
                return "choice is oad but oad is null";
            }
        }else if(this.choice == Choice.ROAD){
            if(this.road != null){
                return "choice: {road: " + this.road + "}";
            }else{
                return "choice is road but road is null";
            }
        } else {
            return "unknown";
        }
    }

}