import { ObjectId } from "mongodb";
import { getDb } from "@/lib/db";

export type AiAnalysisTargetType = "running" | "strength" | "dashboard";

export type AiAnalysisInput = {
  userId: string;
  targetType: AiAnalysisTargetType;
  targetId: ObjectId;
  summary: string;
  tips: string[];
  model: string;
};

export type AiAnalysis = AiAnalysisInput & {
  _id: ObjectId;
  createdAt: Date;
};

export type SerializedAiAnalysis = {
  _id: string;
  targetType: AiAnalysisTargetType;
  targetId: string;
  summary: string;
  tips: string[];
  model: string;
  createdAt: string;
};

export function serializeAnalysis(analysis: AiAnalysis): SerializedAiAnalysis {
  return {
    _id: analysis._id.toString(),
    targetType: analysis.targetType,
    targetId: analysis.targetId.toString(),
    summary: analysis.summary,
    tips: analysis.tips,
    model: analysis.model,
    createdAt: analysis.createdAt.toISOString(),
  };
}

const COLLECTION = "ai_analyses";

const DASHBOARD_TARGET_ID = new ObjectId("000000000000000000000001");

async function getCollection() {
  const db = await getDb();
  return db.collection<AiAnalysis>(COLLECTION);
}

export async function saveAiAnalysis(input: AiAnalysisInput): Promise<AiAnalysis> {
  const collection = await getCollection();
  const doc = { ...input, _id: new ObjectId(), createdAt: new Date() };
  await collection.insertOne(doc);
  return doc;
}

export async function getLatestAnalysisForTarget(
  userId: string,
  targetType: AiAnalysisTargetType,
  targetId: ObjectId
): Promise<AiAnalysis | null> {
  const collection = await getCollection();
  return collection.findOne({ userId, targetType, targetId }, { sort: { createdAt: -1 } });
}

export async function getDashboardAnalysis(userId: string): Promise<AiAnalysis | null> {
  const collection = await getCollection();
  return collection.findOne(
    { userId, targetType: "dashboard", targetId: DASHBOARD_TARGET_ID },
    { sort: { createdAt: -1 } }
  );
}

export async function saveDashboardAnalysis(
  userId: string,
  summary: string,
  tips: string[],
  model: string
): Promise<AiAnalysis> {
  return saveAiAnalysis({
    userId,
    targetType: "dashboard",
    targetId: DASHBOARD_TARGET_ID,
    summary,
    tips,
    model,
  });
}