import type { OptionContractDatabase } from "./interfaces.js";
import { open } from "lmdbx";

const optionContractAggregatesDb = open({
  path: "./option-contract-aggregates.db",
  // any options go here, we can turn on compression like this:
  compression: true,
});

const optionContractExistenceDb = open({
  path: "./option-contract-existence.db",
  // any options go here, we can turn on compression like this:
  compression: true,
});

/** Largest possible key according to the `ordered-binary` (used by lmdbx) docs. */
const MAXIMUM_KEY = Buffer.from([0xff]);

function makeOptionContractDatabase(): OptionContractDatabase {
  const getAggregatesSync = ({
    key: { symbol, expirationDate, strike, type },
    date,
  }) => {
    const startOfDayUnix = new Date(`${date}T00:00:00Z`).valueOf();
    const endOfDayUnix = startOfDayUnix + 3600 * 24 * 1000;
    return optionContractAggregatesDb
      .getRange({
        start: [symbol, expirationDate, strike, type, startOfDayUnix],
        end: [symbol, expirationDate, strike, type, endOfDayUnix],
      })
      .map(({ key, value }) => ({
        tsStart: key[4],
        open: value.open,
        close: value.close,
        high: value.high,
        low: value.low,
      })).asArray;
  };
  const optionContractDatabase: Omit<
    OptionContractDatabase,
    "getOptionContracts"
  > = {
    getKeys: async ({ key: { symbol }, date }) => {
      return optionContractExistenceDb
        .getRange({
          start: [date, symbol],
          end: [date, symbol, MAXIMUM_KEY],
        })
        .map(({ key }) => ({
          symbol,
          expirationDate: key[2],
          strike: key[3],
          type: key[4],
        })).asArray;
    },
    getAggregatesSync,
    getAggregates: async ({
      key: { symbol, expirationDate, strike, type },
      date,
    }) =>
      getAggregatesSync({
        key: { symbol, expirationDate, strike, type },
        date,
      }),
    insertAggregates: async (aggregates) => {
      await optionContractExistenceDb.batch(() => {
        for (const aggregate of aggregates) {
          optionContractExistenceDb.put(
            [
              new Date(aggregate.tsStart).toISOString().substring(0, 10),
              aggregate.key.symbol,
              aggregate.key.expirationDate,
              aggregate.key.strike,
              aggregate.key.type,
            ],
            null
          );
        }
      });
      await optionContractAggregatesDb.batch(() => {
        for (const aggregate of aggregates) {
          optionContractAggregatesDb.put(
            [
              aggregate.key.symbol,
              aggregate.key.expirationDate,
              aggregate.key.strike,
              aggregate.key.type,
              aggregate.tsStart,
            ],
            {
              open: aggregate.open,
              close: aggregate.close,
              high: aggregate.high,
              low: aggregate.low,
            }
          );
        }
      });
    },
    getClosingPrice: async ({
      key: { symbol, strike, type, expirationDate },
    }) => {
      const startOfLastHourUnix = new Date(
        `${expirationDate}T00:00:00Z`
      ).valueOf();
      const endOfLastHourUnix = startOfLastHourUnix + 3600 * 1000;
      let minPrice = 0;
      for (const { value } of optionContractAggregatesDb.getRange({
        start: [symbol, expirationDate, strike, type, startOfLastHourUnix],
        end: [symbol, expirationDate, strike, type, endOfLastHourUnix],
      })) {
        if (value.close < minPrice || minPrice === 0) {
          minPrice = value.close;
        }
      }
      return minPrice;
    },
    getAggregate: async ({
      key: { symbol, expirationDate, strike, type },
      tsStart,
    }) => {
      return await optionContractAggregatesDb.get([
        symbol,
        expirationDate,
        strike,
        type,
        tsStart,
      ]);
    },
  };

  return {
    ...optionContractDatabase,
    getOptionContracts: optionContractDatabase.getKeys,
  };
}

export const database: OptionContractDatabase = makeOptionContractDatabase();