import * as asn1js from "asn1js";
import * as pvutils from "pvutils";
import { AlgorithmIdentifier, AlgorithmIdentifierJson, AlgorithmIdentifierSchema } from "./AlgorithmIdentifier";
import { EMPTY_STRING } from "./constants";
import { AsnError } from "./errors";
import { PkiObject, PkiObjectParameters } from "./PkiObject";
import * as Schema from "./Schema";

const HASH_ALGORITHM = "hashAlgorithm";
const MASK_GEN_ALGORITHM = "maskGenAlgorithm";
const P_SOURCE_ALGORITHM = "pSourceAlgorithm";
const CLEAR_PROPS = [
  HASH_ALGORITHM,
  MASK_GEN_ALGORITHM,
  P_SOURCE_ALGORITHM
];

export interface IRSAESOAEPParams {
  hashAlgorithm: AlgorithmIdentifier;
  maskGenAlgorithm: AlgorithmIdentifier;
  pSourceAlgorithm: AlgorithmIdentifier;
}

export interface RSAESOAEPParamsJson {
  hashAlgorithm?: AlgorithmIdentifierJson;
  maskGenAlgorithm?: AlgorithmIdentifierJson;
  pSourceAlgorithm?: AlgorithmIdentifierJson;
}

export type RSAESOAEPParamsParameters = PkiObjectParameters & Partial<IRSAESOAEPParams>;

/**
 * Class from RFC3447
 */
export class RSAESOAEPParams extends PkiObject implements IRSAESOAEPParams {

  public static override CLASS_NAME = "RSAESOAEPParams";

  public hashAlgorithm!: AlgorithmIdentifier;
  public maskGenAlgorithm!: AlgorithmIdentifier;
  public pSourceAlgorithm!: AlgorithmIdentifier;

  /**
   * Initializes a new instance of the {@link RSAESOAEPParams} class
   * @param parameters Initialization parameters
   */
  constructor(parameters: RSAESOAEPParamsParameters = {}) {
    super();

    this.hashAlgorithm = pvutils.getParametersValue(parameters, HASH_ALGORITHM, RSAESOAEPParams.defaultValues(HASH_ALGORITHM));
    this.maskGenAlgorithm = pvutils.getParametersValue(parameters, MASK_GEN_ALGORITHM, RSAESOAEPParams.defaultValues(MASK_GEN_ALGORITHM));
    this.pSourceAlgorithm = pvutils.getParametersValue(parameters, P_SOURCE_ALGORITHM, RSAESOAEPParams.defaultValues(P_SOURCE_ALGORITHM));

    if (parameters.schema) {
      this.fromSchema(parameters.schema);
    }
  }

  /**
   * Returns default values for all class members
   * @param memberName String name for a class member
   * @returns Default value
   */
  public static override defaultValues(memberName: typeof HASH_ALGORITHM): AlgorithmIdentifier;
  public static override defaultValues(memberName: typeof MASK_GEN_ALGORITHM): AlgorithmIdentifier;
  public static override defaultValues(memberName: typeof P_SOURCE_ALGORITHM): AlgorithmIdentifier;
  public static override defaultValues(memberName: string): any {
    switch (memberName) {
      case HASH_ALGORITHM:
        return new AlgorithmIdentifier({
          algorithmId: "1.3.14.3.2.26", // SHA-1
          algorithmParams: new asn1js.Null()
        });
      case MASK_GEN_ALGORITHM:
        return new AlgorithmIdentifier({
          algorithmId: "1.2.840.113549.1.1.8", // MGF1
          algorithmParams: (new AlgorithmIdentifier({
            algorithmId: "1.3.14.3.2.26", // SHA-1
            algorithmParams: new asn1js.Null()
          })).toSchema()
        });
      case P_SOURCE_ALGORITHM:
        return new AlgorithmIdentifier({
          algorithmId: "1.2.840.113549.1.1.9", // id-pSpecified
          algorithmParams: new asn1js.OctetString({ valueHex: (new Uint8Array([0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55, 0xbf, 0xef, 0x95, 0x60, 0x18, 0x90, 0xaf, 0xd8, 0x07, 0x09])).buffer }) // SHA-1 hash of empty string
        });
      default:
        return super.defaultValues(memberName);
    }
  }

  /**
   * @inheritdoc
   * @asn ASN.1 schema
   * ```asn
   * RSAES-OAEP-params ::= SEQUENCE {
   *    hashAlgorithm     [0] HashAlgorithm    DEFAULT sha1,
   *    maskGenAlgorithm  [1] MaskGenAlgorithm DEFAULT mgf1SHA1,
   *    pSourceAlgorithm  [2] PSourceAlgorithm DEFAULT pSpecifiedEmpty
   * }
   *```
   */
  public static override schema(parameters: Schema.SchemaParameters<{
    hashAlgorithm?: AlgorithmIdentifierSchema;
    maskGenAlgorithm?: AlgorithmIdentifierSchema;
    pSourceAlgorithm?: AlgorithmIdentifierSchema;
  }> = {}): Schema.SchemaType {
    const names = pvutils.getParametersValue<NonNullable<typeof parameters.names>>(parameters, "names", {});

    return (new asn1js.Sequence({
      name: (names.blockName || EMPTY_STRING),
      value: [
        new asn1js.Constructed({
          idBlock: {
            tagClass: 3, // CONTEXT-SPECIFIC
            tagNumber: 0 // [0]
          },
          optional: true,
          value: [AlgorithmIdentifier.schema(names.hashAlgorithm || {})]
        }),
        new asn1js.Constructed({
          idBlock: {
            tagClass: 3, // CONTEXT-SPECIFIC
            tagNumber: 1 // [1]
          },
          optional: true,
          value: [AlgorithmIdentifier.schema(names.maskGenAlgorithm || {})]
        }),
        new asn1js.Constructed({
          idBlock: {
            tagClass: 3, // CONTEXT-SPECIFIC
            tagNumber: 2 // [2]
          },
          optional: true,
          value: [AlgorithmIdentifier.schema(names.pSourceAlgorithm || {})]
        })
      ]
    }));
  }

  public fromSchema(schema: Schema.SchemaType): void {
    // Clear input data first
    pvutils.clearProps(schema, CLEAR_PROPS);

    // Check the schema is valid
    const asn1 = asn1js.compareSchema(schema,
      schema,
      RSAESOAEPParams.schema({
        names: {
          hashAlgorithm: {
            names: {
              blockName: HASH_ALGORITHM
            }
          },
          maskGenAlgorithm: {
            names: {
              blockName: MASK_GEN_ALGORITHM
            }
          },
          pSourceAlgorithm: {
            names: {
              blockName: P_SOURCE_ALGORITHM
            }
          }
        }
      })
    );
    AsnError.assertSchema(asn1, this.className);

    // Get internal properties from parsed schema
    if (HASH_ALGORITHM in asn1.result)
      this.hashAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.hashAlgorithm });

    if (MASK_GEN_ALGORITHM in asn1.result)
      this.maskGenAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.maskGenAlgorithm });

    if (P_SOURCE_ALGORITHM in asn1.result)
      this.pSourceAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.pSourceAlgorithm });
  }

  public toSchema(): asn1js.Sequence {
    //#region Create array for output sequence
    const outputArray = [];

    if (!this.hashAlgorithm.isEqual(RSAESOAEPParams.defaultValues(HASH_ALGORITHM))) {
      outputArray.push(new asn1js.Constructed({
        idBlock: {
          tagClass: 3, // CONTEXT-SPECIFIC
          tagNumber: 0 // [0]
        },
        value: [this.hashAlgorithm.toSchema()]
      }));
    }

    if (!this.maskGenAlgorithm.isEqual(RSAESOAEPParams.defaultValues(MASK_GEN_ALGORITHM))) {
      outputArray.push(new asn1js.Constructed({
        idBlock: {
          tagClass: 3, // CONTEXT-SPECIFIC
          tagNumber: 1 // [1]
        },
        value: [this.maskGenAlgorithm.toSchema()]
      }));
    }

    if (!this.pSourceAlgorithm.isEqual(RSAESOAEPParams.defaultValues(P_SOURCE_ALGORITHM))) {
      outputArray.push(new asn1js.Constructed({
        idBlock: {
          tagClass: 3, // CONTEXT-SPECIFIC
          tagNumber: 2 // [2]
        },
        value: [this.pSourceAlgorithm.toSchema()]
      }));
    }
    //#endregion

    //#region Construct and return new ASN.1 schema for this object
    return (new asn1js.Sequence({
      value: outputArray
    }));
    //#endregion
  }

  public toJSON(): RSAESOAEPParamsJson {
    const res: RSAESOAEPParamsJson = {};

    if (!this.hashAlgorithm.isEqual(RSAESOAEPParams.defaultValues(HASH_ALGORITHM))) {
      res.hashAlgorithm = this.hashAlgorithm.toJSON();
    }

    if (!this.maskGenAlgorithm.isEqual(RSAESOAEPParams.defaultValues(MASK_GEN_ALGORITHM))) {
      res.maskGenAlgorithm = this.maskGenAlgorithm.toJSON();
    }

    if (!this.pSourceAlgorithm.isEqual(RSAESOAEPParams.defaultValues(P_SOURCE_ALGORITHM))) {
      res.pSourceAlgorithm = this.pSourceAlgorithm.toJSON();
    }

    return res;
  }

}