import { AxiosPrometheus, AxiosInstance } from '@biorate/axios-prometheus';
import { Type } from 'avsc';
import { ICompatibilities, ISchemaRegistryConfig } from './interfaces';
import { SchemaRegistryAvroSchemaParseError } from './errors';

export const create = (config: ISchemaRegistryConfig) => {
  const cache = new Map<number, Type>();

  class SchemaRegistryApi extends AxiosPrometheus {
    public baseURL = config.baseURL;
    public headers = config.headers;
    public url: string;
    public method: string;
    private '#client': AxiosInstance;
  }

  class Ping extends SchemaRegistryApi {
    public url = '/';
    public method = 'get';

    public static fetch() {
      return this._fetch<Record<string, unknown>>({});
    }
  }

  class GetSchemasById extends SchemaRegistryApi {
    public url = '/schemas/ids/:id';
    public method = 'get';

    public static fetch(id: number) {
      return this._fetch<{ schema: string }>({ path: { id } });
    }
  }

  class GetSchemasTypes extends SchemaRegistryApi {
    public url = '/schemas/types';
    public method = 'get';

    public static fetch() {
      return this._fetch<string[]>({});
    }
  }

  class GetSchemasVersionsById extends SchemaRegistryApi {
    public url = '/schemas/ids/:id/versions';
    public method = 'get';

    public static fetch(id: number) {
      return this._fetch<{ subject: string; version: number }[]>({ path: { id } });
    }
  }

  class GetSubjects extends SchemaRegistryApi {
    public url = '/subjects';
    public method = 'get';

    public static fetch() {
      return this._fetch<string[]>({});
    }
  }

  class GetSubjectsVersions extends SchemaRegistryApi {
    public url = '/subjects/:subject/versions';
    public method = 'get';

    public static fetch(subject: string) {
      return this._fetch<number[]>({ path: { subject } });
    }
  }

  class DeleteSubjects extends SchemaRegistryApi {
    public url = '/subjects/:subject';
    public method = 'delete';

    public static fetch(data: { subject: string; permanent?: boolean }) {
      return this._fetch<number[]>({
        path: { subject: data.subject },
        params: { permanent: !!data.permanent },
      });
    }
  }

  class GetSubjectsByVersion extends SchemaRegistryApi {
    public url = '/subjects/:subject/versions/:version';
    public method = 'get';

    public static fetch(data: { subject: string; version: number | string }) {
      return this._fetch<{
        subject: string;
        id: number;
        version: number;
        schemaType: string;
        schema: string;
      }>({ path: data });
    }
  }

  class GetSchemaBySubjectsAndVersion extends SchemaRegistryApi {
    public url = '/subjects/:subject/versions/:version/schema';
    public method = 'get';

    public static fetch(data: { subject: string; version: number | string }) {
      return this._fetch<unknown>({ path: data });
    }
  }

  class PostSubjectsVersions extends SchemaRegistryApi {
    public url = '/subjects/:subject/versions';
    public method = 'post';

    public static fetch(data: {
      subject: string;
      schema: string | Record<string, any>;
      schemaType?: string;
      reference?: string;
      normalize?: boolean;
    }) {
      return this._fetch<{ id: number }>({
        path: { subject: data.subject },
        params: { normalize: !!data.normalize },
        data: {
          schema: toStringData(data.schema),
          schemaType: data.schemaType,
          reference: data.reference,
        },
      });
    }
  }

  class PostSubjects extends SchemaRegistryApi {
    public url = '/subjects/:subject';
    public method = 'post';

    public static fetch(data: {
      subject: string;
      schema: string | Record<string, any>;
      schemaType?: string;
      reference?: string;
      normalize?: boolean;
    }) {
      return this._fetch<{
        subject: string;
        id: number;
        version: number;
        schema: string;
      }>({
        path: { subject: data.subject },
        params: { normalize: !!data.normalize },
        data: {
          schema: toStringData(data.schema),
          schemaType: data.schemaType,
          reference: data.reference,
        },
      });
    }
  }

  class PutConfig extends SchemaRegistryApi {
    public url = '/config/:subject';
    public method = 'put';

    public static fetch(data: { subject: string; compatibility: ICompatibilities }) {
      return this._fetch<{
        compatibility: ICompatibilities;
      }>({
        path: { subject: data.subject },
        data: { compatibility: data.compatibility },
      });
    }
  }

  async function encode(
    subject: string,
    data: Record<string, any>,
    version: string | number = 'latest',
  ) {
    const errors: string[] = [];
    const response = await GetSubjectsByVersion.fetch({ subject, version });
    const header = Buffer.alloc(5);
    const schema = Type.forSchema(JSON.parse(response.data.schema));
    schema.isValid(data, {
      errorHook: (path: string[], value: unknown) => {
        errors.push(`${path.join('.')}: ${value} (${typeof value})`);
      },
    });
    if (errors.length) throw new SchemaRegistryAvroSchemaParseError(errors);
    header.writeInt32BE(response.data.id, 1);
    return Buffer.concat([header, schema.toBuffer(data)]);
  }

  async function decode(buffer: Buffer) {
    const id = buffer.readInt32BE(1);
    let data: Type | undefined = cache.get(id);
    if (!data) {
      const response = await GetSchemasById.fetch(id);
      data = Type.forSchema(JSON.parse(response.data.schema));
      cache.set(id, data);
    }
    const schema = Type.forSchema(data);
    return schema.fromBuffer(buffer.slice(5));
  }

  function toStringData(data: string | Record<string, any>) {
    return typeof data === 'string' ? data : JSON.stringify(data);
  }

  return {
    ping: <typeof Ping.fetch>Ping.fetch.bind(Ping),
    getSchemasById: <typeof GetSchemasById.fetch>(
      GetSchemasById.fetch.bind(GetSchemasById)
    ),
    getSchemasTypes: <typeof GetSchemasTypes.fetch>(
      GetSchemasTypes.fetch.bind(GetSchemasTypes)
    ),
    getSchemasVersionsById: <typeof GetSchemasVersionsById.fetch>(
      GetSchemasVersionsById.fetch.bind(GetSchemasVersionsById)
    ),
    getSubjects: <typeof GetSubjects.fetch>GetSubjects.fetch.bind(GetSubjects),
    getSubjectsVersions: <typeof GetSubjectsVersions.fetch>(
      GetSubjectsVersions.fetch.bind(GetSubjectsVersions)
    ),
    deleteSubjects: <typeof DeleteSubjects.fetch>(
      DeleteSubjects.fetch.bind(DeleteSubjects)
    ),
    getSubjectsByVersion: <typeof GetSubjectsByVersion.fetch>(
      GetSubjectsByVersion.fetch.bind(GetSubjectsByVersion)
    ),
    getSchemaBySubjectsAndVersion: <typeof GetSchemaBySubjectsAndVersion.fetch>(
      GetSchemaBySubjectsAndVersion.fetch.bind(GetSchemaBySubjectsAndVersion)
    ),
    postSubjects: <typeof PostSubjects.fetch>PostSubjects.fetch.bind(PostSubjects),
    postSubjectsVersions: <typeof PostSubjectsVersions.fetch>(
      PostSubjectsVersions.fetch.bind(PostSubjectsVersions)
    ),
    putConfig: <typeof PutConfig.fetch>PutConfig.fetch.bind(PutConfig),
    encode,
    decode,
  };
};