import express, { Request, Response, Application } from "express";
import dotenv from "dotenv";

import { createPool } from "mariadb";
import { Book } from "./types/Book";
import {
  checkoutBook,
  findBook,
  getBook,
  listBooks,
  createBook,
  deleteBook,
  editBook,
  returnBook,
} from "./queries";
import { v4 as uuidv4 } from "uuid";
import path from "path";
import session from "express-session";
import { censorBookData } from "./utils/censorBookData";
import * as fs from "fs";
import { checkForThreads } from "./utils/passesSQLInjectionCheck";

dotenv.config();

const app: Application = express();
const port = process.env.PORT || 8000;
let adminKey = process.env.ADMIN_KEY;

const pool = createPool({
  host: process.env.DB_HOST ?? "localhost",
  port: process.env.DB_PORT ? Number(process.env.DB_PORT) : 3306,
  user: process.env.ADMIN_DB_USER ?? "admin",
  password: process.env.ADMIN_DB_PW ?? "AdminPassword",
  database: "librarian",
  connectionLimit: process.env.DB_CONNECTION_LIMIT
    ? Number(process.env.DB_CONNECTION_LIMIT)
    : 10,
});

app.use(express.json());

app.use(
  session({
    secret: adminKey ?? "superSecretKey",
    resave: false,
    saveUninitialized: true,
  })
);

const isAuthenticated = async (
  req: Request<any, any, any, any>,
  res: Response,
  next: () => Promise<void>
) => {
  if (!req.session.authenticated) {
    res.status(403).send("unauthorized");
  } else {
    await next();
  }
};

const stringifyResponse = (obj: unknown) =>
  JSON.stringify(obj, (_, v) => (typeof v === "bigint" ? v.toString() : v));

app.use(express.static(path.join(__dirname, "frontend")));

app.get("/", function (req, res) {
  res.sendFile(path.join(__dirname, "frontend", "index.html"));
});

app.get("/books", function (req, res) {
  res.sendFile(path.join(__dirname, "frontend", "index.html"));
});

app.get("/books/*", function (req, res) {
  res.sendFile(path.join(__dirname, "frontend", "index.html"));
});

app.post(
  "/api/authenticate",
  async (
    req: Request<undefined, undefined, { password: string }>,
    res: Response
  ) => {
    try {
      if (req.body.password === adminKey || req.session.authenticated) {
        req.session.authenticated = true;
        res.status(200).send("ok");
      } else {
        res.status(403).send("unauthorized");
      }
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.post(
  "/api/updateAdminKey",
  async (
    req: Request<
      undefined,
      undefined,
      { oldPassword: string; newPassword: string }
    >,
    res: Response
  ) => {
    try {
      if (req.body.oldPassword === adminKey) {
        if (req.body.newPassword.length < 13) {
          res
            .status(400)
            .send("Admin key must contain at least 13 charakters.");
          return;
        }
        fs.readFile("./.env", "utf8", (err, file) => {
          if (err) return console.log(err);
          const replacedPw = file.replace(
            /ADMIN_KEY=.*/g,
            `ADMIN_KEY=${req.body.newPassword}`
          );
          fs.writeFile("./.env", replacedPw, "utf8", function (err) {
            if (err) return console.log(err);
          });
        });
        adminKey = req.body.newPassword;
        res.status(200).send("ok");
      } else {
        res.status(403).send("unauthorized");
      }
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.post(
  "/api/books/create",
  async (
    req: Request<
      undefined,
      undefined,
      Pick<Book, "isbn" | "title" | "shelf" | "published">
    >,
    res: Response
  ) => {
    isAuthenticated(req, res, async () => {
      const { title, isbn, shelf, published } = req.body;
      try {
        const containsThread = checkForThreads(
          [title, isbn, shelf, published],
          res
        );
        if (containsThread) {
          return;
        }

        const conn = await pool.getConnection();
        const uuid = uuidv4();
        await conn.query(createBook({ ...req.body, uuid }));
        const createdBook = await conn.query(getBook({ uuid }));
        await conn.end();
        res.status(200).send(stringifyResponse(createdBook));
      } catch (error) {
        res.status(500).send("Internal Server Error: " + error);
      }
    });
  }
);

app.post(
  "/api/books/delete",
  async (
    req: Request<undefined, undefined, Pick<Book, "uuid">>,
    res: Response
  ) => {
    await isAuthenticated(req, res, async () => {
      try {
        const containsThread = checkForThreads([req.body.uuid], res);
        if (containsThread) {
          return;
        }

        const conn = await pool.getConnection();
        const foundBooks = await conn.query(getBook(req.body));

        if (!foundBooks.length) {
          await conn.end();
          res.status(404).send("Book not found");
        } else {
          await conn.query(deleteBook(req.body));
          await conn.end();
          res.status(200).send("Book deleted");
        }
      } catch (error) {
        res.status(500).send("Internal Server Error: " + error);
      }
    });
  }
);

app.post(
  "/api/books/edit",
  async (
    req: Request<
      undefined,
      undefined,
      Pick<Book, "uuid" | "isbn" | "title" | "published" | "shelf">
    >,
    res: Response
  ) => {
    await isAuthenticated(req, res, async () => {
      const { uuid, title, isbn, shelf, published } = req.body;

      try {
        const containsThread = checkForThreads(
          [uuid, title, isbn, shelf, published],
          res
        );
        if (containsThread) {
          return;
        }

        const conn = await pool.getConnection();
        const foundBooks = await conn.query(getBook(req.body));

        if (!foundBooks.length) {
          await conn.end();
          res.status(404).send("Book not found");
        } else {
          await conn.query(editBook(req.body));
          await conn.end();
          res.status(200).send("Book moved to shelf");
        }
      } catch (error) {
        res.status(500).send("Internal Server Error: " + error);
      }
    });
  }
);

app.post(
  "/api/books/checkout",
  async (
    req: Request<
      undefined,
      undefined,
      Pick<Book, "uuid" | "checkoutBy" | "contact">
    >,
    res: Response<string>
  ) => {
    const { uuid, checkoutBy, contact } = req.body;

    try {
      const containsThread = checkForThreads([uuid, checkoutBy, contact], res);
      if (containsThread) {
        return;
      }

      const conn = await pool.getConnection();
      const foundBooks = await conn.query(getBook(req.body));

      if (!foundBooks.length) {
        await conn.end();
        res.status(404).send(foundBooks);
      } else {
        await conn.query(
          checkoutBook({ ...req.body, lastCheckoutDate: Date.now() })
        );
        await conn.end();
        res.status(200).send("Book checked out");
      }
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.post(
  "/api/books/find",
  async (
    req: Request<
      undefined,
      undefined,
      Pick<Partial<Book>, "isbn" | "title" | "uuid">
    >,
    res: Response<Book[] | string>
  ) => {
    const { uuid, title, isbn } = req.body;

    try {
      const containsThread = checkForThreads([uuid, title, isbn], res);
      if (containsThread) {
        return;
      }

      if (!isbn && !title && !uuid) {
        res.status(400).send("No isbn or title provided");
        return;
      }

      const conn = await pool.getConnection();
      const foundBooks = await conn.query(findBook(req.body));
      await conn.end();

      if (!foundBooks.length) {
        res.status(404).send("Book not found");
        return;
      }

      res
        .status(200)
        .send(
          stringifyResponse(
            censorBookData(foundBooks, !!req.session.authenticated)
          )
        );
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.get(
  "/api/books/list",
  async (
    req: Request<undefined, undefined, null>,
    res: Response<Book[] | string>
  ) => {
    try {
      const conn = await pool.getConnection();
      const foundBooks = await conn.query(listBooks);
      await conn.end();
      res
        .status(200)
        .send(
          stringifyResponse(
            censorBookData(foundBooks, !!req.session.authenticated)
          )
        );
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.post(
  "/api/books/return",
  async (
    req: Request<
      undefined,
      undefined,
      Pick<Book, "uuid" | "checkoutBy" | "contact">
    >,
    res: Response
  ) => {
    const { uuid, checkoutBy, contact } = req.body;

    try {
      const containsThread = checkForThreads([uuid, checkoutBy, contact], res);
      if (containsThread) {
        return;
      }

      const conn = await pool.getConnection();
      const foundBooks = await conn.query<Book[]>(getBook(req.body));

      if (!foundBooks.length) {
        await conn.end();
        res.status(404).send("Book not found");
        return;
      }

      if (
        !req.session.authenticated &&
        !(
          foundBooks[0].checkoutBy === req.body.checkoutBy &&
          foundBooks[0].contact === req.body.contact
        )
      ) {
        res.status(403).send("unauthorized");
        return;
      }

      await conn.query(returnBook(req.body));
      await conn.end();
      res.status(200).send("Book returned");
    } catch (error) {
      res.status(500).send("Internal Server Error: " + error);
    }
  }
);

app.listen(port, async () => {
  console.log(`Server listening on port ${port}`);
});