const express = require('express');
const Joi = require('joi');
const app = express();

const courses = [
    {id: 1, name: `course1`},
    {id: 2, name: `course2`},
    {id: 3, name: `course3`},
];

app.use(express.json());

// hello world
app.get(`/`, (req, res) => {
    res.send(`Hello World`);
});

// get all courses
app.get(`/api/courses`, (req, res) => {
    res.send(courses);
});

// get course by id
app.get(`/api/courses/:id`, (req, res) => {
    const course = courses.find((course) => course.id === parseInt(req.params.id));
    if (!course) {
        res.status(404).send(`The course with ID ${req.params.id} not found!`)
    } else {
        res.send(course);
    }
});

// create course
app.post(`/api/courses`, (req, res) => {
    const schema = {
        name: Joi.string().min(3).required()
    };
    const result = Joi.validate(req.body, schema);
    if (result.error) {
        res.status(400).send(result.error.details[0].message);
        return;
    }

    const course = {
        id: courses.length + 1,
        name: req.body.name
    };
    courses.push(course);
    res.send(course);
});

// update course
app.put(`/api/courses/:id`, (req, res) => {
    const requestId = parseInt(req.params.id);
    const course = courses.find((course) => course.id === requestId);
    if (!course) {
        res.status(404).send(`no course with id: ${requestId}`);
        return;
    }

    const schema = {
        name: Joi.string().min(3).required()
    };
    const result = Joi.validate(req.body, schema);
    if (result.error) {
        res.status(400).send(result.error.details[0].message);
        return;
    }
    const arrayId = courses.findIndex((course) => course.id === requestId);
    const newCourse = {
        ...courses[arrayId],
        name: req.body.name
    };
    courses[arrayId] = newCourse;
    res.send(newCourse);
});

// delete course
app.delete(`/api/courses/:id`, (req, res) => {
    const requestId = parseInt(req.params.id);
    const course = courses.find((course) => course.id === requestId);
    if (!course) {
        res.status(404).send(`no course with id: ${requestId}`);
        return;
    }

    const arrayId = courses.findIndex((course) => course.id === requestId);
    const deletedCourse = courses.splice(arrayId, 1);
    res.send(deletedCourse[0]);
});

app.listen(3000, () => console.log(`Listening on port 3000...`));