import {
  type Experimental_EvaluationModelV4 as EvaluationModelV4,
  type EmbeddingModelV4,
  type Experimental_VideoModelV3,
  type Experimental_VideoModelV4,
  type FilesV4,
  type ImageModelV4,
  type LanguageModelV4,
  NoSuchModelError,
  type ProviderV3,
  type ProviderV4,
  type RerankingModelV4,
  type SkillsV4,
  type SpeechModelV4,
  type TranscriptionModelV4,
} from '@ai-sdk/provider';
import type { EvaluationProvider } from '../evaluate/evaluation-provider';
import { resolveEvaluationModel } from '../model/resolve-model';
import { wrapImageModel } from '../middleware/wrap-image-model';
import { wrapLanguageModel } from '../middleware/wrap-language-model';
import { asProviderV4 } from '../model/as-provider-v4';
import { asVideoModelV4 } from '../model/as-video-model-v4';
import type { ImageModelMiddleware, LanguageModelMiddleware } from '../types';
import type { ExtractLiteralUnion } from '../util/extract-literal-union';
import { NoSuchProviderError } from './no-such-provider-error';

type ProviderWithOptionalVideoModel = {
  videoModel?: (
    modelId: string,
  ) => Experimental_VideoModelV3 | Experimental_VideoModelV4;
};

type RegistryModelType =
  | 'languageModel'
  | 'embeddingModel'
  | 'imageModel'
  | 'transcriptionModel'
  | 'speechModel'
  | 'rerankingModel'
  | 'videoModel'
  | 'evaluationModel';

type ProviderVideoModelIdentifier<PROVIDER> = PROVIDER extends {
  videoModel: (...args: infer ARGS) => unknown;
}
  ? ExtractLiteralUnion<ARGS[0]>
  : never;

type ProviderEvaluationModelIdentifier<PROVIDER> = PROVIDER extends {
  evaluationModel: (...args: infer ARGS) => unknown;
}
  ? ExtractLiteralUnion<ARGS[0]>
  : never;

/** Registry with experimental evaluation access, separate from the stable interface. */
export type EvaluationProviderRegistry<
  PROVIDERS extends Record<string, ProviderV4 | ProviderV3> = Record<
    string,
    ProviderV4 | ProviderV3
  >,
  SEPARATOR extends string = ':',
> = ProviderRegistryProvider<PROVIDERS, SEPARATOR> & {
  evaluationModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ProviderEvaluationModelIdentifier<PROVIDERS[KEY]>}`
      : never,
  ): EvaluationModelV4;
  evaluationModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): EvaluationModelV4;
};

export interface ProviderRegistryProvider<
  PROVIDERS extends Record<string, ProviderV4 | ProviderV3> = Record<
    string,
    ProviderV4 | ProviderV3
  >,
  SEPARATOR extends string = ':',
> {
  languageModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['languageModel']>>[0]>}`
      : never,
  ): LanguageModelV4;
  languageModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): LanguageModelV4;

  embeddingModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['embeddingModel']>>[0]>}`
      : never,
  ): EmbeddingModelV4;
  embeddingModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): EmbeddingModelV4;

  imageModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['imageModel']>>[0]>}`
      : never,
  ): ImageModelV4;
  imageModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): ImageModelV4;

  transcriptionModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['transcriptionModel']>>[0]>}`
      : never,
  ): TranscriptionModelV4;
  transcriptionModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): TranscriptionModelV4;

  speechModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['speechModel']>>[0]>}`
      : never,
  ): SpeechModelV4;
  speechModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): SpeechModelV4;

  rerankingModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ExtractLiteralUnion<Parameters<NonNullable<PROVIDERS[KEY]['rerankingModel']>>[0]>}`
      : never,
  ): RerankingModelV4;
  rerankingModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): RerankingModelV4;

  videoModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string
      ? `${KEY & string}${SEPARATOR}${ProviderVideoModelIdentifier<PROVIDERS[KEY]>}`
      : never,
  ): Experimental_VideoModelV4;
  videoModel<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? `${KEY & string}${SEPARATOR}${string}` : never,
  ): Experimental_VideoModelV4;

  files<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? KEY & string : never,
  ): FilesV4;

  skills<KEY extends keyof PROVIDERS>(
    id: KEY extends string ? KEY & string : never,
  ): SkillsV4;
}

/**
 * Creates a registry for the given providers with optional middleware functionality.
 * This function allows you to register multiple providers and optionally apply middleware
 * to all language models from the registry, enabling you to transform parameters, wrap generate
 * operations, and wrap stream operations for every language model accessed through the registry.
 *
 * @param providers - A record of provider instances to be registered in the registry.
 * @param options - Configuration options for the provider registry.
 * @param options.separator - The separator used between provider ID and model ID in the combined identifier. Defaults to ':'.
 * @param options.languageModelMiddleware - Optional middleware to be applied to all language models from the registry. When multiple middlewares are provided, the first middleware will transform the input first, and the last middleware will be wrapped directly around the model.
 * @param options.imageModelMiddleware - Optional middleware to be applied to all image models from the registry. When multiple middlewares are provided, the first middleware will transform the input first, and the last middleware will be wrapped directly around the model.
 * @returns A new ProviderRegistryProvider instance that provides access to all registered providers with optional middleware applied to language and image models.
 */
export function createProviderRegistry<
  PROVIDERS extends Record<string, ProviderV4 | ProviderV3>,
  SEPARATOR extends string = ':',
>(
  providers: PROVIDERS,
  {
    separator = ':' as SEPARATOR,
    languageModelMiddleware,
    imageModelMiddleware,
  }: {
    separator?: SEPARATOR;
    languageModelMiddleware?:
      | LanguageModelMiddleware
      | LanguageModelMiddleware[];
    imageModelMiddleware?: ImageModelMiddleware | ImageModelMiddleware[];
  } = {},
): EvaluationProviderRegistry<PROVIDERS, SEPARATOR> {
  const registry = new DefaultProviderRegistry<PROVIDERS, SEPARATOR>({
    separator,
    languageModelMiddleware,
    imageModelMiddleware,
  });

  for (const [id, provider] of Object.entries(providers)) {
    registry.registerProvider({ id, provider } as {
      id: keyof PROVIDERS;
      provider: PROVIDERS[keyof PROVIDERS];
    });
  }

  return registry;
}

/**
 * @deprecated Use `createProviderRegistry` instead.
 */
export const experimental_createProviderRegistry = createProviderRegistry;

class DefaultProviderRegistry<
  PROVIDERS extends Record<string, ProviderV4 | ProviderV3>,
  SEPARATOR extends string,
>
  implements
    ProviderRegistryProvider<PROVIDERS, SEPARATOR>,
    EvaluationProviderRegistry<PROVIDERS, SEPARATOR>
{
  private providers: Partial<
    Record<
      keyof PROVIDERS,
      ProviderV4 & ProviderWithOptionalVideoModel & EvaluationProvider
    >
  > = {};
  private separator: SEPARATOR;
  private languageModelMiddleware?:
    | LanguageModelMiddleware
    | LanguageModelMiddleware[];
  private imageModelMiddleware?: ImageModelMiddleware | ImageModelMiddleware[];

  constructor({
    separator,
    languageModelMiddleware,
    imageModelMiddleware,
  }: {
    separator: SEPARATOR;
    languageModelMiddleware?:
      | LanguageModelMiddleware
      | LanguageModelMiddleware[];
    imageModelMiddleware?: ImageModelMiddleware | ImageModelMiddleware[];
  }) {
    this.separator = separator;
    this.languageModelMiddleware = languageModelMiddleware;
    this.imageModelMiddleware = imageModelMiddleware;
  }

  registerProvider<K extends keyof PROVIDERS>({
    id,
    provider,
  }: {
    id: K;
    provider: PROVIDERS[K];
  }): void {
    const providerV4 = asProviderV4(provider);
    const videoModel = (
      provider as ProviderWithOptionalVideoModel
    ).videoModel?.bind(provider);

    const evaluationModel = (
      provider as EvaluationProvider
    ).evaluationModel?.bind(provider);

    const registeredProvider =
      videoModel == null
        ? providerV4
        : Object.assign(Object.create(Object.getPrototypeOf(providerV4)), {
            ...providerV4,
            videoModel: (modelId: string) =>
              asVideoModelV4(videoModel(modelId)),
          });

    // Keep v4 instances intact. Adapted providers need the original evaluation receiver.
    if (registeredProvider !== provider && evaluationModel != null) {
      Object.assign(registeredProvider, { evaluationModel });
    }
    this.providers[id] = registeredProvider;
  }

  private getProvider(
    id: string,
    modelType: RegistryModelType,
  ): ProviderV4 & ProviderWithOptionalVideoModel & EvaluationProvider {
    const provider = this.providers[id as keyof PROVIDERS];

    if (provider == null) {
      throw new NoSuchProviderError({
        modelId: id,
        modelType,
        providerId: id,
        availableProviders: Object.keys(this.providers),
      });
    }

    return provider;
  }

  private splitId(id: string, modelType: RegistryModelType): [string, string] {
    const index = id.indexOf(this.separator);

    if (index === -1) {
      throw new NoSuchModelError({
        modelId: id,
        modelType,
        message:
          `Invalid ${modelType} id for registry: ${id} ` +
          `(must be in the format "providerId${this.separator}modelId")`,
      });
    }

    return [id.slice(0, index), id.slice(index + this.separator.length)];
  }

  languageModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): LanguageModelV4 {
    const [providerId, modelId] = this.splitId(id, 'languageModel');
    let model = this.getProvider(providerId, 'languageModel').languageModel?.(
      modelId,
    );

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'languageModel' });
    }

    if (this.languageModelMiddleware != null) {
      model = wrapLanguageModel({
        model,
        middleware: this.languageModelMiddleware,
      });
    }

    return model;
  }

  embeddingModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): EmbeddingModelV4 {
    const [providerId, modelId] = this.splitId(id, 'embeddingModel');
    const provider = this.getProvider(providerId, 'embeddingModel');

    const model = provider.embeddingModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({
        modelId: id,
        modelType: 'embeddingModel',
      });
    }

    return model;
  }

  imageModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): ImageModelV4 {
    const [providerId, modelId] = this.splitId(id, 'imageModel');
    const provider = this.getProvider(providerId, 'imageModel');

    let model = provider.imageModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'imageModel' });
    }

    if (this.imageModelMiddleware != null) {
      model = wrapImageModel({
        model,
        middleware: this.imageModelMiddleware,
      });
    }

    return model;
  }

  transcriptionModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): TranscriptionModelV4 {
    const [providerId, modelId] = this.splitId(id, 'transcriptionModel');
    const provider = this.getProvider(providerId, 'transcriptionModel');

    const model = provider.transcriptionModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({
        modelId: id,
        modelType: 'transcriptionModel',
      });
    }

    return model;
  }

  speechModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): SpeechModelV4 {
    const [providerId, modelId] = this.splitId(id, 'speechModel');
    const provider = this.getProvider(providerId, 'speechModel');

    const model = provider.speechModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'speechModel' });
    }

    return model;
  }

  rerankingModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): RerankingModelV4 {
    const [providerId, modelId] = this.splitId(id, 'rerankingModel');
    const provider = this.getProvider(providerId, 'rerankingModel');

    const model = provider.rerankingModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'rerankingModel' });
    }

    return model;
  }

  videoModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): Experimental_VideoModelV4 {
    const [providerId, modelId] = this.splitId(id, 'videoModel');
    const provider = this.getProvider(providerId, 'videoModel');

    const model = provider.videoModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'videoModel' });
    }

    return asVideoModelV4(model);
  }

  evaluationModel<KEY extends keyof PROVIDERS>(
    id: `${KEY & string}${SEPARATOR}${string}`,
  ): EvaluationModelV4 {
    const [providerId, modelId] = this.splitId(id, 'evaluationModel');
    const provider = this.getProvider(providerId, 'evaluationModel');
    const model = provider.evaluationModel?.(modelId);

    if (model == null) {
      throw new NoSuchModelError({ modelId: id, modelType: 'evaluationModel' });
    }

    return resolveEvaluationModel(model);
  }

  files<KEY extends keyof PROVIDERS>(id: KEY & string): FilesV4 {
    const provider = this.getProvider(id, 'languageModel');
    const files = provider.files?.();

    if (files == null) {
      throw new Error(
        `The provider "${id}" does not support file uploads. Make sure it exposes a files() method.`,
      );
    }

    return files;
  }

  skills<KEY extends keyof PROVIDERS>(id: KEY & string): SkillsV4 {
    const provider = this.getProvider(id, 'languageModel');
    const skills = provider.skills?.();

    if (skills == null) {
      throw new Error(
        `The provider "${id}" does not support skills. Make sure it exposes a skills() method.`,
      );
    }

    return skills;
  }
}