import { Pool, PoolClient } from "pg";

import { Question } from "../platforms";
import { measureTime } from "../utils/measureTime";
import { roughSizeOfObject } from "../utils/roughSize";

const questionTableNames = ["questions", "history"];

const allTableNames = [...questionTableNames, "dashboards", "frontpage"];

/* Postgres database connection code */
const databaseURL = process.env.DIGITALOCEAN_POSTGRES;
export const pool = new Pool({
  connectionString: databaseURL,
  ssl: process.env.POSTGRES_NO_SSL
    ? false
    : {
        rejectUnauthorized: false,
      },
});

// Read
export async function pgRead({ tableName }: { tableName: string }) {
  if (!allTableNames.includes(tableName)) {
    throw Error(
      `Table ${tableName} not in whitelist; stopping to avoid tricky sql injections`
    );
  }
  let command = `SELECT * from ${tableName}`;
  return (await pool.query(command)).rows;
}

export async function pgBulkInsert({
  data,
  tableName,
  client,
}: {
  data: Question[];
  tableName: string;
  client: PoolClient;
}) {
  if (!questionTableNames.includes(tableName)) {
    throw Error(
      `Table ${tableName} not in whitelist; stopping to avoid tricky sql injections`
    );
  }

  const generateQuery = (rows: number) => {
    let text = `INSERT INTO ${tableName} VALUES`;
    const cols = 10;
    const parts: string[] = [];
    for (let r = 0; r < rows; r++) {
      const bits = [];
      for (let c = 1; c <= cols; c++) {
        bits.push(`$${cols * r + c}`);
      }
      parts.push("(" + bits.join(", ") + ")");
    }

    text += parts.join(", ");
    return text;
  };

  let from = 0;
  const chunkSize = 20;
  while (from < data.length - 1) {
    const take = Math.min(chunkSize, data.length - from);
    const query = generateQuery(take);

    const chunk = [];
    for (let i = from; i < from + take; i++) {
      const datum = data[i];
      let timestamp =
        datum.timestamp &&
        !!datum.timestamp.slice &&
        !isNaN(Date.parse(datum.timestamp))
          ? datum.timestamp
          : new Date().toISOString();
      timestamp = timestamp.slice(0, 19).replace("T", " ");
      const values = [
        datum.id,
        datum.title,
        datum.url,
        datum.platform,
        datum.description || "",
        JSON.stringify(datum.options || []),
        timestamp, // fix
        datum.stars ||
          (datum.qualityindicators ? datum.qualityindicators.stars : 2),
        JSON.stringify(datum.qualityindicators || []),
        JSON.stringify(datum.extra || []),
      ];
      chunk.push(...values);
    }

    console.log(`Inserting ${from + 1}..${from + take}`);
    from += take;
    await client.query(query, chunk);
  }
}

export async function pgUpsert({
  contents,
  tableName,
  replacePlatform,
}: {
  contents: Question[];
  tableName: string;
  replacePlatform?: string;
}) {
  if (!questionTableNames.includes(tableName)) {
    throw Error(
      `Table ${tableName} not in whitelist; stopping to avoid tricky sql injections`
    );
  }

  await measureTime(async () => {
    const client = await pool.connect();
    try {
      await client.query("BEGIN");
      if (replacePlatform) {
        await client.query(`DELETE FROM ${tableName} WHERE platform = $1`, [
          replacePlatform,
        ]);
      }
      console.log(
        `Upserting ${contents.length} rows into postgres table ${tableName}.`
      );

      await pgBulkInsert({ data: contents, tableName, client });
      console.log(
        `Inserted ${
          contents.length
        } rows with approximate cummulative size ${roughSizeOfObject(
          contents
        )} MB into ${tableName}.`
      );

      console.log("Sample: ");
      console.log(
        JSON.stringify(
          // only show the first three options
          contents.slice(0, 1).map((question) => ({
            ...question,
            options: question.options
              ? question.options.length > 3
                ? question.options.slice(0, 3).concat("...")
                : question.options
              : null,
          })),
          null,
          4
        )
      );
      await client.query("COMMIT");
    } catch (e) {
      await client.query("ROLLBACK");
      throw e;
    } finally {
      client.release();
    }
  });
}