/**
 * 树莓派状态 JSON 数据接口
 */
require('dotenv').config()
const fs = require('fs')
const http = require('http')
const hostname = require('os').hostname()
const exec = require('child_process').exec
const MEMINFO_FILE_PATH = '/proc/meminfo'
const TEMPERATURE_FILE_PATH = '/sys/class/thermal/thermal_zone0/temp'
const server = http.createServer(function (request, response) {
    response.setHeader('Access-Control-Allow-Origin', '*')
    response.setHeader('Access-Control-Allow-Methods', 'HEAD,GET,POST,OPTIONS,PATCH,PUT,DELETE')
    response.setHeader('Access-Control-Allow-Headers', 'Origin,X-Requested-With,Authorization,Content-Type,Accept,Z-Key')
    response.setHeader('Content-Type', 'application/json')
    try {
        const temp_string = fs.readFileSync(TEMPERATURE_FILE_PATH)
        const meminfo_string = String(fs.readFileSync(MEMINFO_FILE_PATH))
        const meminfo_total = meminfo_string.match(/MemTotal\:\s+(\d+) kB/)
        const meminfo_available = meminfo_string.match(/MemAvailable\:\s+(\d+) kB/)
        const result = {
            hostname,
            cpu: {
                temperature: Number((temp_string / 1000).toFixed(3)),
            },
            memory: {
                total: Number((meminfo_total[1] / 1024).toFixed(2)),
                available: Number((meminfo_available[1] / 1024).toFixed(2))
            },
        }
        exec("cat /proc/stat |grep cpu |tail -1|awk '{print ($5*100)/($2+$3+$4+$5+$6+$7+$8+$9+$10)}'|awk '{print 100 - $1}'", (err, stdout, stderr) => {
            result.cpu.load = Number((stdout / 100).toFixed(4))
            response.end(JSON.stringify(result))
        })
    } catch (error) {
        response.statusCode = 500
        response.end(JSON.stringify({ error }))
    }
})
const port = process.env.PORT || 3000
const host = process.env.HOST || 'localhost'
server.listen(port, host, () => console.log(`rpi status http server running at http://${host}:${port}`))