package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"os"
	"time"
)

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

const (
	hostDefault = "127.0.0.1:8085"
	hostDesc    = "open hardware monitor host [OSHW_HOST]"
)

func run() error {
	conifg := getConfig()
	node, err := fetchNode(conifg.host)
	if err != nil {
		return err
	}
	fmt.Printf("%s", node)
	return nil
}

type config struct {
	host string
}

func getConfig() *config {
	c := config{}
	host := os.Getenv("OHWM_HOST")
	hostFlag := flag.String("host", hostDefault, hostDesc)
	flag.Parse()
	if *hostFlag != hostDefault {
		host = *hostFlag
	}
	if host == "" {
		host = hostDefault
	}
	c.host = host
	return &c
}

func fetchNode(host string) (*node, error) {
	client := http.Client{Timeout: time.Second}
	u := url.URL{Scheme: "http", Host: host, Path: "/data.json"}
	resp, err := client.Get(u.String())
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	node := &node{}
	decoder := json.NewDecoder(resp.Body)
	if err := decoder.Decode(node); err != nil {
		return nil, err
	}
	return node, nil
}

type node struct {
	ID       int `json:"id"`
	ImageURL string
	Max      string
	Min      string
	Text     string
	Value    string
	Children []node
}

func (n *node) String() string {
	return n.stringify(0)
}

func (n *node) stringify(indent int) string {
	prefix := ""
	for i := 0; i < indent; i++ {
		prefix += "  "
	}

	ret := prefix + n.Text
	if n.Value != "" {
		ret += ": " + n.Value
	}
	if n.Max != "" && n.Min != "" && n.Max != "-" && n.Min != "-" {
		ret += fmt.Sprintf(" (%s - %s)", n.Min, n.Max)
	}
	ret += "\n"
	for _, child := range n.Children {
		ret += child.stringify(indent + 1)
	}

	return ret
}