package client

import (
	"bufio"
	"context"
	"encoding/json"
	"io"
	"maps"
	"strconv"
	"strings"

	"github.com/prometheus/client_golang/prometheus"
	"repositories.action2quare.com/ayo/gocommon/logger"
	"repositories.action2quare.com/ayo/gocommon/metric"
)

type pipeListener struct {
	config   clientConfig
	registry *prometheus.Registry
}

func run_metric_pipe_reader(config clientConfig, registry *prometheus.Registry, ctx context.Context) {
	r := &pipeListener{
		config:   config,
		registry: registry,
	}

	go r.listen(ctx)
}

type pipeReader struct {
	handle      io.ReadCloser
	constLabels map[string]string
	collector   *metric.PrometheusCollector
}

func (l *pipeListener) startReader(r io.ReadCloser) {
	reader := pipeReader{
		handle:      r,
		constLabels: l.config.ConstLabels,
		collector:   metric.NewPrometheusCollector(l.config.MetricNamespace, l.registry),
	}
	defer func() {
		reader.close(l.registry)
	}()

	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		reader.parseLine(scanner.Text())
	}
}

func (r *pipeReader) close(registry *prometheus.Registry) {
	registry.Unregister(r.collector)
	r.handle.Close()
}

func (r *pipeReader) parseLine(line string) {
	defer func() {
		r := recover()
		if r != nil {
			logger.Println(r)
		}
	}()

	switch line[0] {
	case '{':
		var desc metric.MetricDescription
		if err := json.Unmarshal([]byte(line), &desc); err != nil {
			logger.Println("unmarshal metric failed :", err, line)
			return
		}

		if desc.ConstLabels == nil {
			desc.ConstLabels = make(map[string]string)
		}

		maps.Copy(desc.ConstLabels, r.constLabels)
		r.collector = r.collector.RegisterMetric(&desc)

	default:
		kv := strings.Split(line, ":")
		if len(kv) != 2 {
			return
		}

		if len(kv[1]) == 0 {
			r.collector = r.collector.UnregisterMetric(kv[0])
		} else {
			if val, err := strconv.ParseFloat(kv[1], 64); err == nil {
				r.collector.UpdateMetric(kv[0], val)
			}
		}
	}
}