import { IntelligenceBackend, BackendConfigSection, BackendUnavailableError } from "./types.js";
import { OpencodeBackend } from "./opencode.js";
import { OpenAIBackend } from "./openai.js";
import { OllamaLocalBackend } from "./ollama-local.js";
import { OllamaCloudBackend } from "./ollama-cloud.js";
import { AnthropicBackend } from "./anthropic.js";

const AUTO_DETECT_ORDER: Array<"opencode" | "openai" | "ollama-local" | "ollama-cloud" | "anthropic"> = [
  "opencode",
  "openai",
  "ollama-local",
  "ollama-cloud",
  "anthropic",
];

export function createBackend(
  name: string,
  config: BackendConfigSection
): IntelligenceBackend {
  switch (name) {
    case "opencode":
      return new OpencodeBackend(config.agent_backends.opencode);
    case "openai":
      if (!config.llm_backends["openai"]) {
        throw new BackendUnavailableError("openai");
      }
      return new OpenAIBackend(config.llm_backends["openai"]);
    case "ollama-local":
      return new OllamaLocalBackend(config.llm_backends["ollama-local"]);
    case "ollama-cloud":
      return new OllamaCloudBackend(config.llm_backends["ollama-cloud"]);
    case "anthropic":
      if (!config.llm_backends["anthropic"]) {
        throw new BackendUnavailableError("anthropic");
      }
      return new AnthropicBackend(config.llm_backends["anthropic"]);
    default:
      throw new BackendUnavailableError(name);
  }
}

export async function resolveBackend(
  config: BackendConfigSection
): Promise<IntelligenceBackend> {
  if (config.provider !== "auto") {
    const backend = createBackend(config.provider, config);
    if (!(await backend.isAvailable())) {
      throw new BackendUnavailableError(config.provider);
    }
    return backend;
  }

  for (const name of AUTO_DETECT_ORDER) {
    try {
      const backend = createBackend(name, config);
      if (await backend.isAvailable()) {
        return backend;
      }
    } catch {}
  }

  throw new BackendUnavailableError("auto");
}

export { IntelligenceBackend, BackendConfigSection, BackendUnavailableError } from "./types.js";
export { LLMBaseBackend, ChatMessage, ChatCompletionResponse } from "./llm-base.js";
export { ToolRegistry, ToolDefinition, ToolCall, ToolResult } from "./tool-registry.js";
export { OpencodeBackend } from "./opencode.js";
export { OpenAIBackend } from "./openai.js";
export { OllamaLocalBackend } from "./ollama-local.js";
export { OllamaCloudBackend } from "./ollama-cloud.js";
export { AnthropicBackend } from "./anthropic.js";