const express = require('express');
const bodyParser = require('body-parser');
const xlsx = require('xlsx');
const fs = require('fs');
const { exec } = require('child_process');
const app = express();
const port = 3000;
const filePath = './data/todos.xlsx';

app.use(bodyParser.json());
app.use(express.static('public'));

function readTodos() {
    if (fs.existsSync(filePath)) {
        const workbook = xlsx.readFile(filePath);
        const sheet = workbook.Sheets[workbook.SheetNames[0]];
        return xlsx.utils.sheet_to_json(sheet);
    } else {
        return [];
    }
}

function writeTodos(todos) {
    const worksheet = xlsx.utils.json_to_sheet(todos);
    const workbook = xlsx.utils.book_new();
    xlsx.utils.book_append_sheet(workbook, worksheet, 'Todos');
    xlsx.writeFile(workbook, filePath);
}

app.get('/todos', (req, res) => {
    const todos = readTodos();
    res.json({ data: todos });
});

app.post('/todos', (req, res) => {
    const todos = readTodos();
    const task = req.body.task;
    const newTodo = { id: todos.length ? todos[todos.length - 1].id + 1 : 1, task: task };
    todos.push(newTodo);
    writeTodos(todos);
    res.json({ data: newTodo });
});

app.delete('/todos/:id', (req, res) => {
    const todos = readTodos();
    const updatedTodos = todos.filter(todo => todo.id != req.params.id);
    writeTodos(updatedTodos);
    res.json({ message: "success" });
});

app.get('/count-a', (req, res) => {
    const todos = readTodos();
    const allTasks = todos.map(todo => todo.task).join('\n');
    fs.writeFileSync('tasks.txt', allTasks);
    exec('awk -f count_a.awk tasks.txt', (error, stdout) => {
        res.json({ count: parseInt(stdout.trim(), 10) });
    });
});

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