interface ModelProvider {
  readonly providerId: string;
  readonly modelId: string;
  generate(messages: ChatMessage[], options?: ModelConfig & { tools?: ToolDefinition[] }): Promise<ModelResponse>;
  stream(messages: ChatMessage[], options?: ModelConfig & { tools?: ToolDefinition[] }): AsyncGenerator<StreamChunk>;
}

import { registry } from "@agentium/core";
import { MyCustomProvider } from "./MyCustomProvider.js";

registry.register("my-provider", (modelId, config) => {
  return new MyCustomProvider(modelId, config as { apiKey?: string });
});

// Use it
const model = registry.resolve("my-provider", "my-model-v1", {
  apiKey: process.env.MY_API_KEY,
});

import {
  Agent,
  registry,
  type ModelProvider,
  type ChatMessage,
  type ModelResponse,
  type StreamChunk,
} from "@agentium/core";

class CohereProvider implements ModelProvider {
  readonly providerId = "cohere";
  readonly modelId: string;
  private apiKey: string;

  constructor(modelId: string, config: { apiKey: string }) {
    this.modelId = modelId;
    this.apiKey = config.apiKey;
  }

  async generate(messages: ChatMessage[]): Promise<ModelResponse> {
    const res = await fetch("https://api.cohere.ai/v1/chat", {
      method: "POST",
      headers: {
        Authorization: `Bearer ${this.apiKey}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        model: this.modelId,
        message: messages[messages.length - 1]?.content,
      }),
    });
    const data = await res.json();
    return {
      message: { role: "assistant", content: data.text },
      usage: data.meta?.tokens ?? { promptTokens: 0, completionTokens: 0, totalTokens: 0 },
      finishReason: "stop",
      raw: data,
    };
  }

  async *stream(): AsyncGenerator<StreamChunk> {
    // Implement streaming if your API supports it
    yield { type: "finish", finishReason: "stop", usage: undefined };
  }
}

registry.register("cohere", (modelId, config) => {
  return new CohereProvider(modelId, config as { apiKey: string });
});

const model = registry.resolve("cohere", "command-r", {
  apiKey: process.env.COHERE_API_KEY,
});

const agent = new Agent({ name: "Cohere Agent", model });