import type {
  ComparisonRequest,
  ComparisonResult,
  ResearchProgress,
} from "./types";
import { generateComparison } from "./providers/openai";

export type {
  ComparisonRequest,
  ComparisonResult,
  ResearchProgress,
} from "./types";

export async function* runResearch(
  request: ComparisonRequest
): AsyncGenerator<ResearchProgress> {
  yield { stage: "parsing", message: "Analyzing comparison request..." };

  if (!request.items || request.items.length < 2) {
    yield {
      stage: "error",
      error: "At least 2 items are required for comparison",
    };
    return;
  }

  for (let i = 0; i < request.items.length; i++) {
    yield {
      stage: "researching",
      item: request.items[i],
      progress: Math.round(((i + 0.5) / request.items.length) * 80),
    };
  }

  yield {
    stage: "synthesizing",
    message: "Synthesizing research into structured comparison...",
  };

  try {
    const result = await generateComparison(request);
    yield { stage: "complete", result };
  } catch (error) {
    yield {
      stage: "error",
      error:
        error instanceof Error ? error.message : "Research failed unexpectedly",
    };
  }
}

export async function executeResearch(
  request: ComparisonRequest
): Promise<ComparisonResult> {
  for await (const progress of runResearch(request)) {
    if (progress.stage === "complete") {
      return progress.result;
    }
    if (progress.stage === "error") {
      throw new Error(progress.error);
    }
  }

  throw new Error("Research completed without producing a result");
}