package collector

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"net"
	"net/http"
	"text/template"
	"time"

	"git.loyso.art/frx/devsim/internal/entities"
)

type upsertRequest struct {
	IncomingTraffic int `json:"incoming_traffic"`
	OutgoingTraffic int `json:"outgoing_traffic"`
	IncomingRPS     int `json:"incoming_rps"`
	ReadRPS         int `json:"read_rps"`
	WriteRPS        int `json:"write_rps"`
}

type Client interface {
	Upsert(context.Context, entities.DeviceStatistics) error
}

type client struct {
	httpClient *http.Client
	baseurl    string
}

func New(addr string) (*client, error) {
	hc := &http.Client{
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   time.Second * 10,
				KeepAlive: time.Second * 30,
			}).DialContext,
			MaxIdleConns:          10,
			MaxConnsPerHost:       100,
			IdleConnTimeout:       time.Second * 90,
			TLSHandshakeTimeout:   time.Second * 5,
			ExpectContinueTimeout: time.Second * 1,
			ForceAttemptHTTP2:     true,
		},
		Timeout: time.Second * 10,
	}

	return &client{
		httpClient: hc,
		baseurl:    addr,
	}, nil
}

var upsertRequestTemplate = template.Must(template.New("request").Parse(`{"incoming_traffic":{{.IncomingTrafficBytes}},"outgoing_traffic":{{.OutgoingTrafficBytes}},"incoming_rps":{{.IncomingRPS}},"read_rps":{{.ReadRPS}},"write_rps":{{.WriteRPS}}}`))

func (c *client) Upsert(ctx context.Context, stat entities.DeviceStatistics) error {
	var buf bytes.Buffer
	err := upsertRequestTemplate.Lookup("request").Execute(&buf, stat)
	if err != nil {
		return fmt.Errorf("executing template: %w", err)
	}

	path := c.baseurl + "/api/v1/stats/" + string(stat.ID)
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, path, &buf)
	if err != nil {
		return fmt.Errorf("preparing http request: %w", err)
	}

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("executing request: %w", err)
	}

	if resp.StatusCode == http.StatusOK {
		return nil
	}

	data, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
	if err != nil {
		return fmt.Errorf("reading body by status code %d: %w", resp.StatusCode, err)
	}

	return fmt.Errorf("expected status 200 got %d with body: %q", resp.StatusCode, data)
}