import { eq, sql } from "drizzle-orm";
import dayjs from "dayjs";
import { useDrizzle } from "@/lib/db.js";
import { chargePoint, connector, idTag, meterValue, transaction } from "@/db/schema.js";
import type {
  StopTransactionRequest,
  StopTransactionResponse,
  OcppConnectionContext,
} from "../types.ts";
import { resolveIdTagInfo } from "./authorize.ts";

export async function handleStopTransaction(
  payload: StopTransactionRequest,
  _ctx: OcppConnectionContext,
): Promise<StopTransactionResponse> {
  const db = useDrizzle();

  // Update the transaction record
  const [tx] = await db
    .update(transaction)
    .set({
      stopTimestamp: dayjs(payload.timestamp).toDate(),
      stopMeterValue: payload.meterStop,
      stopIdTag: payload.idTag ?? null,
      stopReason: (payload.reason as (typeof transaction.$inferSelect)["stopReason"]) ?? null,
      updatedAt: dayjs().toDate(),
    })
    .where(eq(transaction.id, payload.transactionId))
    .returning();

  if (!tx) {
    console.warn(`[OCPP] StopTransaction: transaction ${payload.transactionId} not found`);
    return {};
  }

  // Set connector back to Available
  await db
    .update(connector)
    .set({ status: "Available", updatedAt: dayjs().toDate() })
    .where(eq(connector.id, tx.connectorId));

  // Store embedded meter values (transactionData)
  if (payload.transactionData?.length) {
    const records = payload.transactionData.flatMap((mv) =>
      mv.sampledValue?.length
        ? [
            {
              id: crypto.randomUUID(),
              transactionId: tx.id,
              connectorId: tx.connectorId,
              chargePointId: tx.chargePointId,
              connectorNumber: tx.connectorNumber,
              timestamp: dayjs(mv.timestamp).toDate(),
              sampledValues:
                mv.sampledValue as unknown as (typeof meterValue.$inferInsert)["sampledValues"],
            },
          ]
        : [],
    );
    if (records.length) {
      await db.insert(meterValue).values(records);
    }
  }

  const energyWh = payload.meterStop - tx.startMeterValue;

  // Deduct balance from the idTag based on actual energy consumed
  const [cp] = await db
    .select({ feePerKwh: chargePoint.feePerKwh })
    .from(chargePoint)
    .where(eq(chargePoint.id, tx.chargePointId))
    .limit(1);

  const feeFen =
    cp && cp.feePerKwh > 0 && energyWh > 0 ? Math.ceil((energyWh * cp.feePerKwh) / 1000) : 0;

  // Always record the charge amount (0 if free)
  await db
    .update(transaction)
    .set({ chargeAmount: feeFen, updatedAt: dayjs().toDate() })
    .where(eq(transaction.id, tx.id));

  if (feeFen > 0) {
    await db
      .update(idTag)
      .set({
        balance: sql`${idTag.balance} - ${feeFen}`,
        updatedAt: dayjs().toDate(),
      })
      .where(eq(idTag.idTag, tx.idTag));
  }

  console.log(
    `[OCPP] StopTransaction txId=${payload.transactionId} ` +
      `reason=${payload.reason ?? "none"} energyWh=${energyWh} feeFen=${feeFen}`,
  );

  // Resolve idTagInfo for the stop tag if provided (no balance check — charging already occurred)
  const idTagInfo = payload.idTag ? await resolveIdTagInfo(payload.idTag, false) : undefined;

  return { idTagInfo };
}