Add DuckDuckGo integration for search functionality

Implemented a DuckDuckGo search module with configurable SafeSearch and regional settings. Added a CLI tool to perform searches via DuckDuckGo using browser automation, supporting flags for customization.

sites/duckduckgo/duckduckgo.go

@@ -0,0 +1,126 @@
+package duckduckgo
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/url"
+
+	"gitea.stevedudenhoeffer.com/steve/go-extractor"
+)
+
+type SafeSearch int
+
+const (
+	SafeSearchOn       SafeSearch = 1
+	SafeSearchModerate SafeSearch = -1
+	SafeSearchOff      SafeSearch = -2
+)
+
+type Config struct {
+	// SafeSearch is the safe-search level to use. If empty, SafeSearchOff will be used.
+	SafeSearch SafeSearch
+
+	// Region is the region to use for the search engine.
+	// See: https://duckduckgo.com/duckduckgo-help-pages/settings/params/ for more values
+	Region string
+}
+
+func (c Config) validate() Config {
+	if c.SafeSearch == 0 {
+		c.SafeSearch = SafeSearchOff
+	}
+
+	return c
+}
+func (c Config) ToSearchURL(query string) *url.URL {
+	c = c.validate()
+
+	res, _ := url.Parse("https://duckduckgo.com/")
+
+	var vals = res.Query()
+
+	switch c.SafeSearch {
+	case SafeSearchOn:
+		vals.Set("kp", "1")
+	case SafeSearchModerate:
+		vals.Set("kp", "-1")
+	case SafeSearchOff:
+		vals.Set("kp", "-2")
+	}
+
+	if c.Region != "" {
+		vals.Set("kl", c.Region)
+	}
+
+	vals.Set("q", query)
+
+	res.RawQuery = vals.Encode()
+
+	return res
+}
+
+var DefaultConfig = Config{
+	SafeSearch: SafeSearchOff,
+}
+
+type Result struct {
+	URL         string
+	Title       string
+	Description string
+}
+
+func deferClose(cl io.Closer) {
+	if cl != nil {
+		_ = cl.Close()
+	}
+}
+
+func (c Config) Search(ctx context.Context, b extractor.Browser, query string) ([]Result, error) {
+	u := c.ToSearchURL(query)
+
+	slog.Info("searching", "url", u, "query", query, "config", c, "browser", b)
+	doc, err := b.Open(ctx, u.String(), extractor.OpenPageOptions{})
+	defer deferClose(doc)
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to open url: %w", err)
+	}
+
+	var res []Result
+
+	err = doc.ForEach(`article[id^="r1-"]`, func(n extractor.Node) error {
+		var r Result
+
+		links := n.Select(`a[href][target="_self"]`)
+
+		if len(links) == 0 {
+			return nil
+		}
+
+		r.URL, err = links[0].Attr(`href`)
+
+		if err != nil {
+			return fmt.Errorf("failed to get link: %w", err)
+		}
+
+		titles := n.Select("div:nth-child(2) > div:nth-child(1) > div:nth-child(2) > p:nth-child(1)")
+
+		if len(titles) != 0 {
+			r.Title, _ = titles[0].Text()
+		}
+
+		descriptions := n.Select("span > span")
+
+		if len(descriptions) != 0 {
+			r.Description, _ = descriptions[0].Text()
+		}
+
+		res = append(res, r)
+
+		return nil
+	})
+
+	return res, nil
+}