package apache

import (
	"bufio"
	"fmt"
	"net"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/influxdb/telegraf/plugins"
)

type Apache struct {
	Urls []string
}

var sampleConfig = `
# An array of Apache status URI to gather stats.
urls = ["http://localhost/server-status?auto"]
`

func (n *Apache) SampleConfig() string {
	return sampleConfig
}

func (n *Apache) Description() string {
	return "Read Apache status information (mod_status)"
}

func (n *Apache) Gather(acc plugins.Accumulator) error {
	var wg sync.WaitGroup
	var outerr error

	for _, u := range n.Urls {
		addr, err := url.Parse(u)
		if err != nil {
			return fmt.Errorf("Unable to parse address '%s': %s", u, err)
		}

		wg.Add(1)
		go func(addr *url.URL) {
			defer wg.Done()
			outerr = n.gatherUrl(addr, acc)
		}(addr)
	}

	wg.Wait()

	return outerr
}

var tr = &http.Transport{
	ResponseHeaderTimeout: time.Duration(3 * time.Second),
}

var client = &http.Client{Transport: tr}

func (n *Apache) gatherUrl(addr *url.URL, acc plugins.Accumulator) error {
	resp, err := client.Get(addr.String())
	if err != nil {
		return fmt.Errorf("error making HTTP request to %s: %s", addr.String(), err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("%s returned HTTP status %s", addr.String(), resp.Status)
	}
	
	tags := getTags(addr)
	
	sc := bufio.NewScanner(resp.Body)
	for sc.Scan() {
	    line := sc.Text()
	    if strings.Contains(line, ":") {
	        
            parts := strings.SplitN(line, ":", 2)
            key, part := strings.Replace(parts[0], " ", "", -1), strings.TrimSpace(parts[1])
            
	        switch key {
	            
                case "Scoreboard":
                    n.gatherScores(part, acc, tags)
                default:
                    value, err := strconv.ParseFloat(part, 32)
                    if err != nil {
                        continue
                    }
                    acc.Add(key, value, tags)
	        }
	    }
	}

	return nil
}

func (n *Apache) gatherScores(data string, acc plugins.Accumulator, tags map[string]string) {
    
    var waiting, open int = 0, 0
    var S, R, W, K, D, C, L, G, I int = 0, 0, 0, 0, 0, 0, 0, 0, 0
    
    for _, s := range strings.Split(data, "") {
        
        switch s {
            case "_": waiting++
            case "S": S++
            case "R": R++
            case "W": W++
            case "K": K++
            case "D": D++
            case "C": C++
            case "L": L++
            case "G": G++
            case "I": I++
            case ".": open++
        }
    }
    
    acc.Add("scboard_waiting",      float64(waiting), tags);
    acc.Add("scboard_starting",     float64(S),       tags);
    acc.Add("scboard_reading",      float64(R),       tags);
    acc.Add("scboard_sending",      float64(W),       tags);
    acc.Add("scboard_keepalive",    float64(K),       tags);
    acc.Add("scboard_dnslookup",    float64(D),       tags);
    acc.Add("scboard_closing",      float64(C),       tags);
    acc.Add("scboard_logging",      float64(L),       tags);
    acc.Add("scboard_finishing",    float64(G),       tags);
    acc.Add("scboard_idle_cleanup", float64(I),       tags);
    acc.Add("scboard_open",         float64(open),    tags);
}

// Get tag(s) for the apache plugin
func getTags(addr *url.URL) map[string]string {
	h := addr.Host
	var htag string
	if host, _, err := net.SplitHostPort(h); err == nil {
		htag = host
	} else {
		htag = h
	}
	return map[string]string{"server": htag}
}

func init() {
	plugins.Add("apache", func() plugins.Plugin {
		return &Apache{}
	})
}