package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
)

func AddCaddyRoute(cfg *Config, fqdn string, port string) error {
	if err := addCaddyAPIRoute(cfg, fqdn, port); err != nil {
		return fmt.Errorf("caddy API: %w", err)
	}

	if err := appendCaddyfile(cfg, fqdn, port); err != nil {
		return fmt.Errorf("caddyfile: %w", err)
	}

	return nil
}

func addCaddyAPIRoute(cfg *Config, fqdn string, port string) error {
	route := map[string]interface{}{
		"match": []map[string]interface{}{
			{"host": []string{fqdn}},
		},
		"handle": []map[string]interface{}{
			{
				"handler": "reverse_proxy",
				"upstreams": []map[string]string{
					{"dial": "localhost:" + port},
				},
			},
		},
	}

	payload, err := json.Marshal(route)
	if err != nil {
		return fmt.Errorf("marshaling route: %w", err)
	}

	url := cfg.CaddyAdminURL + "/config/apps/http/servers/srv0/routes"

	req, err := http.NewRequest("POST", url, bytes.NewReader(payload))
	if err != nil {
		return fmt.Errorf("creating request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(body))
	}

	return nil
}

func appendCaddyfile(cfg *Config, fqdn string, port string) error {
	block := fmt.Sprintf("\n%s {\n\treverse_proxy localhost:%s\n}\n", fqdn, port)

	f, err := os.OpenFile(cfg.CaddyfilePath, os.O_APPEND|os.O_WRONLY, 0644)
	if err != nil {
		return fmt.Errorf("opening Caddyfile: %w", err)
	}
	defer f.Close()

	if _, err := f.WriteString(block); err != nil {
		return fmt.Errorf("writing to Caddyfile: %w", err)
	}

	return nil
}