import { Context, Effect, Schema } from "effect"
import type { ExportSettings } from "./settings"

// ---- errors ----

export class EncodeError extends Schema.TaggedErrorClass<EncodeError>()("EncodeError", {
  message: Schema.String,
  cause: Schema.optional(Schema.Unknown),
}) {}

// ---- service ----

export interface ImageEncoderShape {
  /**
   * Encode an RGBA `ImageData` frame to the requested format/settings,
   * downscaling first when the scale is below 100%. Platform-neutral bytes
   * out — the caller picks the Blob/mime.
   */
  readonly encode: (input: {
    readonly image: ImageData
    readonly settings: ExportSettings
  }) => Effect.Effect<Uint8Array, EncodeError>
}

/**
 * The export encoder. The engine defines the contract; the implementation
 * is swappable behind this service — jSquash wasm codecs (the default
 * layer), native encoders, or a server round-trip (see
 * docs/adr/0006-image-encoder-engine-service.md).
 */
export class ImageEncoder extends Context.Service<ImageEncoder, ImageEncoderShape>()(
  "ImageEncoder",
) {}