package appupdate

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"time"

	"github.com/root-kdw12/hetzner-api-dyndns-records-webinterface/internal/updateprotocol"
)

type AgentClient struct {
	socket string
}

func NewAgentClient(socket string) *AgentClient {
	return &AgentClient{socket: socket}
}

func (c *AgentClient) Start(ctx context.Context, request updateprotocol.Request) error {
	encoded, err := json.Marshal(request)
	if err != nil {
		return err
	}
	response, err := c.do(ctx, http.MethodPost, "/v1/update", bytes.NewReader(encoded))
	if err != nil {
		return err
	}
	defer response.Body.Close()
	if response.StatusCode == http.StatusAccepted {
		return nil
	}
	if response.StatusCode == http.StatusConflict {
		return errors.New("ein Software-Update läuft bereits")
	}
	return fmt.Errorf("Update-Agent antwortet mit HTTP %d", response.StatusCode)
}

func (c *AgentClient) Status(ctx context.Context) (updateprotocol.Status, error) {
	response, err := c.do(ctx, http.MethodGet, "/v1/status", nil)
	if err != nil {
		return updateprotocol.Status{}, err
	}
	defer response.Body.Close()
	if response.StatusCode != http.StatusOK {
		return updateprotocol.Status{}, fmt.Errorf("Update-Agent antwortet mit HTTP %d", response.StatusCode)
	}
	var status updateprotocol.Status
	if err := json.NewDecoder(io.LimitReader(response.Body, 64<<10)).Decode(&status); err != nil {
		return updateprotocol.Status{}, fmt.Errorf("Status des Update-Agents lesen: %w", err)
	}
	return status, nil
}

func (c *AgentClient) do(ctx context.Context, method, path string, body io.Reader) (*http.Response, error) {
	if c == nil || c.socket == "" {
		return nil, errors.New("Update-Agent ist nicht konfiguriert")
	}
	transport := &http.Transport{
		DisableKeepAlives: true,
		DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
			dialer := net.Dialer{Timeout: time.Second}
			return dialer.DialContext(ctx, "unix", c.socket)
		},
	}
	client := &http.Client{Transport: transport, Timeout: 3 * time.Second}
	request, err := http.NewRequestWithContext(ctx, method, "http://update-agent"+path, body)
	if err != nil {
		return nil, err
	}
	if body != nil {
		request.Header.Set("Content-Type", "application/json")
	}
	response, err := client.Do(request)
	if err != nil {
		return nil, errors.New("Update-Agent ist nicht erreichbar")
	}
	return response, nil
}