// SPDX-License-Identifier: EUPL-1.2

// Package pairing handles the handshake between LetheanGateway and lthn.io.
//
//	client := pairing.NewClient("https://lthn.io", "api-key", "charon", "eu-west", "10.69.69.165:51820")
//	client.Pair()
//	client.Heartbeat(stats)
package pairing

import (
	"encoding/json"
	"net/http"

	core "dappco.re/go/core"
)

// Client manages the pairing lifecycle with lthn.io.
type Client struct {
	apiURL            string
	apiKey            string
	name              string
	region            string
	wireguardEndpoint string
}

// NewClient creates a pairing client for the given gateway.
//
//	client := pairing.NewClient("https://lthn.io", "key", "charon", "eu-west", "10.0.0.1:51820")
func NewClient(apiURL, apiKey, name, region, wireguardEndpoint string) *Client {
	return &Client{
		apiURL:            apiURL,
		apiKey:            apiKey,
		name:              name,
		region:            region,
		wireguardEndpoint: wireguardEndpoint,
	}
}

// Pair registers this gateway with lthn.io.
//
//	err := client.Pair()
func (c *Client) Pair() error {
	body := map[string]interface{}{
		"name":               c.name,
		"capabilities":       []string{"vpn", "dns", "proxy"},
		"region":             c.region,
		"bandwidth_mbps":     100,
		"max_connections":    50,
		"wireguard_endpoint": c.wireguardEndpoint,
	}

	data, _ := json.Marshal(body)
	request, err := http.NewRequest("POST", c.apiURL+"/v1/gateway/pair", core.NewReader(string(data)))
	if err != nil {
		return core.E("pairing.Pair", "failed to create request", err)
	}
	request.Header.Set("Content-Type", "application/json")
	if c.apiKey != "" {
		request.Header.Set("Authorization", "Bearer "+c.apiKey)
	}

	response, err := http.DefaultClient.Do(request)
	if err != nil {
		return core.E("pairing.Pair", "request failed", err)
	}
	defer response.Body.Close()

	if response.StatusCode != 200 {
		return core.E("pairing.Pair", core.Sprintf("status %d", response.StatusCode), nil)
	}

	return nil
}

// Heartbeat sends alive status + stats to lthn.io.
//
//	err := client.Heartbeat(map[string]interface{}{"connections": 5, "load": 23})
func (c *Client) Heartbeat(stats map[string]interface{}) error {
	stats["name"] = c.name
	data, _ := json.Marshal(stats)

	request, err := http.NewRequest("POST", c.apiURL+"/v1/gateway/heartbeat", core.NewReader(string(data)))
	if err != nil {
		return core.E("pairing.Heartbeat", "failed to create request", err)
	}
	request.Header.Set("Content-Type", "application/json")
	if c.apiKey != "" {
		request.Header.Set("Authorization", "Bearer "+c.apiKey)
	}

	response, err := http.DefaultClient.Do(request)
	if err != nil {
		return core.E("pairing.Heartbeat", "request failed", err)
	}
	defer response.Body.Close()

	return nil
}