package crud;

import java.sql.*;

import io.javalin.Javalin;
import io.javalin.http.Context;
import io.javalin.rendering.template.JavalinJte;
import static io.javalin.rendering.template.TemplateUtil.model;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class App {
    private static Logger logger;
    private static Connection connection;

    public static void main(String[] args) throws SQLException {
        logger = LoggerFactory.getLogger(App.class);
        connection = DriverManager.getConnection("jdbc:postgresql:books");

        initializeDB();

        Javalin.create(config -> {
                config.requestLogger.http((ctx, ms) -> {  // log each request
                        logger.info("" + ctx.statusCode() + " " + ctx.method() + " " + ctx.path());
                    });
                config.fileRenderer(new JavalinJte());  // render using JTE
            })
            // now set up all the routes
            .get("/", App::listRoute)
            .get("/list", App::listRoute)
            .post("/add", App::addRoute)
            .get("/view", App::viewRoute)
            .get("/edit", App::editGetRoute)
            .post("/edit", App::editPostRoute)
            .get("/delete", App::deleteGetRoute)
            .post("/delete", App::deletePostRoute)
            .start(7070);
    }

    // set up the tables if needed
    // insert sample data if needed
    private static void initializeDB() throws SQLException {
        Statement statement = connection.createStatement();
        statement.executeUpdate("""
            CREATE TABLE IF NOT EXISTS books(
              id SERIAL PRIMARY KEY,
              title TEXT,
              author TEXT
            )
        """);

        ResultSet rs = statement.executeQuery("SELECT count(*) AS c FROM books");
        rs.next();
        if (rs.getInt("c") == 0) {  // the books table is empty, so add some sample data
            statement.executeUpdate("""
                INSERT INTO books(title, author) 
                  VALUES
                    ('Types and Programming Languages', 'Benjamin C. Pierce'),
                    ('Database Systems: The Complete Book',
                       'Hector Garcia-Molina, Jeff Ullman, and Jennifer Widom')
            """);
        }

        statement.close();
    }

    ////////////////////////////////////////////////////////////////////////////
    // Rest of this file contains the implementation of the routes
    ////////////////////////////////////////////////////////////////////////////

    private static void listRoute(Context ctx) throws SQLException {
        // ctx.render uses JTE to instantiate a template with given params
        //
        // see app/src/main/jte/list.html for the definition of this template
        ctx.render("list.html", model("books", Book.list(connection)));
    }

    private static void viewRoute(Context ctx) throws SQLException {
        String idParam = ctx.queryParam("id");

        if (idParam == null) {
            ctx.status(400);
            ctx.result("must provide id query param");
            return;
        }

        Integer targetId = 0;
        try {
            targetId = Integer.parseInt(idParam);
        } catch (NumberFormatException e) {
            ctx.status(400);
            ctx.result("id '" + idParam + "' does not appear to be an integer");
            return;
        }

        Book book = Book.getById(connection, targetId);

        if (book == null) {
            ctx.status(400);
            ctx.result("no book with id " + targetId);
            return;
        }

        ctx.render("view.html", model("book", book));
    }

    private static void editGetRoute(Context ctx) throws SQLException {
        String idParam = ctx.queryParam("id");

        if (idParam == null) {
            ctx.status(400);
            ctx.result("must provide id query param");
            return;
        }

        Integer targetId = 0;
        try {
            targetId = Integer.parseInt(idParam);
        } catch (NumberFormatException e) {
            ctx.status(400);
            ctx.result("id '" + idParam + "' does not appear to be an integer");
            return;
        }

        Book book = Book.getById(connection, targetId);

        if (book == null) {
            ctx.status(400);
            ctx.result("no book with id " + targetId);
            return;
        }

        ctx.render("edit.html", model("book", book));
    }

    private static void editPostRoute(Context ctx) throws SQLException {
        String idParam = ctx.formParam("id");

        if (idParam == null) {
            ctx.status(400);
            ctx.result("malformed edit POST request missing id param");
            return;
        }

        Integer targetId = 0;
        try {
            targetId = Integer.parseInt(idParam);
        } catch (NumberFormatException e) {
            ctx.status(400);
            ctx.result("malformed edit POST request: id '" + idParam +
                       "' does not appear to be an integer");
            return;
        }

        String titleParam = ctx.formParam("title");
        if (titleParam == null) {
            ctx.status(400);
            ctx.result("malformed edit POST request missing title param");
            return;
        }

        String authorParam = ctx.formParam("author");
        if (authorParam == null) {
            ctx.status(400);
            ctx.result("malformed edit POST request missing author param");
            return;
        }

        Book book = Book.getById(connection, targetId);

        if (book == null) {
            ctx.status(400);
            ctx.result("malformed our out of date edit POST request: no book with id " + targetId);
            return;
        }

        book.title = titleParam;
        book.author = authorParam;

        book.save(connection);

        ctx.redirect("/list");
    }

    private static void deleteGetRoute(Context ctx) throws SQLException {
        String idParam = ctx.queryParam("id");

        if (idParam == null) {
            ctx.status(400);
            ctx.result("must provide id query param");
            return;
        }

        Integer targetId = 0;
        try {
            targetId = Integer.parseInt(idParam);
        } catch (NumberFormatException e) {
            ctx.status(400);
            ctx.result("id '" + idParam + "' does not appear to be an integer");
            return;
        }

        Book book = Book.getById(connection, targetId);

        if (book == null) {
            ctx.status(400);
            ctx.result("no book with id " + targetId);
            return;
        }

        ctx.render("delete.html", model("book", book));
    }

    private static void deletePostRoute(Context ctx) throws SQLException {
        String idParam = ctx.formParam("id");

        if (idParam == null) {
            ctx.status(400);
            ctx.result("malformed delete POST request missing id param");
            return;
        }

        Integer targetId = 0;
        try {
            targetId = Integer.parseInt(idParam);
        } catch (NumberFormatException e) {
            ctx.status(400);
            ctx.result("malformed delete POST request: id '" + idParam +
                       "' does not appear to be an integer");
            return;
        }

        Book book = Book.getById(connection, targetId);

        if (book == null) {
            ctx.status(400);
            ctx.result("malformed our out of date delete POST request: no book with id " + targetId);
            return;
        }

        book.delete(connection);

        ctx.redirect("/list");
    }

    private static void addRoute(Context ctx) throws SQLException {
        String titleParam = ctx.formParam("title");
        if (titleParam == null) {
            ctx.status(400);
            ctx.result("malformed add POST request missing title param");
            return;
        }

        String authorParam = ctx.formParam("author");
        if (authorParam == null) {
            ctx.status(400);
            ctx.result("malformed add POST request missing author param");
            return;
        }

        Book b = Book.create(connection, titleParam, authorParam);

        logger.info(b.toString());


        ctx.redirect("/list");
    }
}