package collectors

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"strconv"
	"strings"
	"time"

	cclog "github.com/ClusterCockpit/cc-metric-collector/internal/ccLogger"
	lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
	stats "github.com/ClusterCockpit/cc-metric-collector/internal/metricRouter"
)

//
// LoadavgCollector collects:
// * load average of last 1, 5 & 15 minutes
// * number of processes currently runnable
// * total number of processes in system
//
// See: https://www.kernel.org/doc/html/latest/filesystems/proc.html
//
const LOADAVGFILE = "/proc/loadavg"

type LoadavgCollector struct {
	metricCollector
	tags         map[string]string
	load_matches []string
	load_skips   []bool
	proc_matches []string
	proc_skips   []bool
	config       struct {
		ExcludeMetrics []string `json:"exclude_metrics,omitempty"`
	}
	statsProcessedMetrics int64
}

func (m *LoadavgCollector) Init(config json.RawMessage) error {
	m.name = "LoadavgCollector"
	m.setup()
	if len(config) > 0 {
		err := json.Unmarshal(config, &m.config)
		if err != nil {
			return err
		}
	}
	m.meta = map[string]string{
		"source": m.name,
		"group":  "LOAD"}
	m.tags = map[string]string{"type": "node"}
	m.load_matches = []string{
		"load_one",
		"load_five",
		"load_fifteen"}
	m.load_skips = make([]bool, len(m.load_matches))
	m.proc_matches = []string{
		"proc_run",
		"proc_total"}
	m.proc_skips = make([]bool, len(m.proc_matches))

	for i, name := range m.load_matches {
		_, m.load_skips[i] = stringArrayContains(m.config.ExcludeMetrics, name)
	}
	for i, name := range m.proc_matches {
		_, m.proc_skips[i] = stringArrayContains(m.config.ExcludeMetrics, name)
	}
	m.statsProcessedMetrics = 0
	m.init = true
	return nil
}

func (m *LoadavgCollector) Read(interval time.Duration, output chan lp.CCMetric) {
	if !m.init {
		return
	}
	buffer, err := ioutil.ReadFile(LOADAVGFILE)
	if err != nil {
		if err != nil {
			cclog.ComponentError(
				m.name,
				fmt.Sprintf("Read(): Failed to read file '%s': %v", LOADAVGFILE, err))
		}
		return
	}
	now := time.Now()

	// Load metrics
	ls := strings.Split(string(buffer), ` `)
	for i, name := range m.load_matches {
		x, err := strconv.ParseFloat(ls[i], 64)
		if err != nil {
			cclog.ComponentError(
				m.name,
				fmt.Sprintf("Read(): Failed to convert '%s' to float64: %v", ls[i], err))
			continue
		}
		if m.load_skips[i] {
			continue
		}
		y, err := lp.New(name, m.tags, m.meta, map[string]interface{}{"value": x}, now)
		if err == nil {
			output <- y
			m.statsProcessedMetrics++
		}
	}

	// Process metrics
	lv := strings.Split(ls[3], `/`)
	for i, name := range m.proc_matches {
		x, err := strconv.ParseInt(lv[i], 10, 64)
		if err != nil {
			cclog.ComponentError(
				m.name,
				fmt.Sprintf("Read(): Failed to convert '%s' to float64: %v", lv[i], err))
			continue
		}
		if m.proc_skips[i] {
			continue
		}
		y, err := lp.New(name, m.tags, m.meta, map[string]interface{}{"value": x}, now)
		if err == nil {
			output <- y
			m.statsProcessedMetrics++
		}
	}
	stats.ComponentStatInt(m.name, "processed_metrics", m.statsProcessedMetrics)
}

func (m *LoadavgCollector) Close() {
	m.init = false
}