import { XllmError } from "../core/errors";
import type {
  XChatWithToolsOptions,
  XClientOptions,
  XMessage,
  XRequest,
  XToolCall,
  XToolErrorStrategy,
  XToolExecutorMap,
} from "../core/types";
import { resolveConfig } from "../runtime/config";
import { runToolCall } from "./tool-loop-shared";

export interface ToolLoopConfig {
  provider: string;
  maxRounds: number;
  strategy: XToolErrorStrategy;
}

export interface ToolLoopAccumulator {
  rounds: number;
  toolCallsExecuted: number;
  currentMessages: XMessage[];
}

export const createToolLoopConfig = (
  input: XChatWithToolsOptions,
  options: XClientOptions,
): ToolLoopConfig => {
  const resolved = resolveConfig(input, options);
  const maxRounds = input.maxRounds ?? 5;
  const strategy = input.toolErrorStrategy ?? "throw";
  if (maxRounds < 1) {
    throw new XllmError({
      code: "INVALID_REQUEST",
      message: "maxRounds must be >= 1",
      provider: resolved.provider,
    });
  }
  return { provider: resolved.provider, maxRounds, strategy };
};

export const buildRequestBase = (
  input: XChatWithToolsOptions,
  stream: boolean,
): Omit<XRequest, "messages"> => ({
  tools: input.tools,
  toolChoice: input.toolChoice,
  stream,
  temperature: input.temperature,
  topP: input.topP,
  maxTokens: input.maxTokens,
  metadata: input.metadata,
  provider: input.provider,
  model: input.model,
  apiKey: input.apiKey,
  baseURL: input.baseURL,
  providerExtras: input.providerExtras,
});

export const buildAssistantMessage = (
  text: string,
  toolCalls: XToolCall[],
  reasoning?: string,
): XMessage => ({
  role: "assistant",
  content: text,
  toolCalls,
  ...(reasoning ? { reasoningContent: reasoning } : {}),
});

export const executeToolCalls = async (
  provider: string,
  toolCalls: XToolCall[],
  executors: XToolExecutorMap,
  strategy: XToolErrorStrategy,
): Promise<{ toolMessages: XMessage[]; toolCallsExecuted: number }> => {
  const toolMessages: XMessage[] = [];
  let toolCallsExecuted = 0;
  for (const toolCall of toolCalls) {
    const toolRunResult = await runToolCall(provider, toolCall, executors, strategy);
    if (!toolRunResult.handled || !toolRunResult.message) {
      continue;
    }
    toolMessages.push(toolRunResult.message);
    toolCallsExecuted += 1;
  }
  return { toolMessages, toolCallsExecuted };
};

export function throwIfMaxRoundsExceeded(config: ToolLoopConfig): never {
  throw new XllmError({
    code: "PROVIDER_ERROR",
    message: `Tool loop exceeded maxRounds=${config.maxRounds}`,
    provider: config.provider,
  });
}