package client

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/url"
	"time"
)

type idleTimeoutConn struct {
	net.Conn
	idleTimeout time.Duration
}

func (c *idleTimeoutConn) Read(b []byte) (int, error) {
	if err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout)); err != nil {
		return 0, err
	}
	return c.Conn.Read(b)
}

func (c *Client) CrawlDomain(domain string, subdomains bool, callback func(line string) error) error {
	path := fmt.Sprintf("/crawl/%s", url.PathEscape(domain))
	fullURL := c.config.BaseURL + path

	if subdomains {
		params := url.Values{}
		params.Set("subdomains", "true")
		fullURL += "?" + params.Encode()
	}

	ctx := context.Background()
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fullURL, nil)
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("User-Agent", c.config.UserAgent)

	idleTimeout := 60 * time.Second
	streamClient := &http.Client{
		Transport: &http.Transport{
			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
				conn, err := (&net.Dialer{
					Timeout:   30 * time.Second,
					KeepAlive: 30 * time.Second,
				}).DialContext(ctx, network, addr)
				if err != nil {
					return nil, err
				}
				return &idleTimeoutConn{
					Conn:        conn,
					idleTimeout: idleTimeout,
				}, nil
			},
		},
	}

	resp, err := streamClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to execute request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	scanner := bufio.NewScanner(resp.Body)
	for scanner.Scan() {
		line := scanner.Text()
		if len(line) == 0 {
			continue
		}

		if err := callback(line); err != nil {
			return err
		}
	}

	if err := scanner.Err(); err != nil {
		return fmt.Errorf("stream reading error: %w", err)
	}

	return nil
}