Add DuckDuckGo support and refactor caching system

Introduced DuckDuckGo as a new search provider alongside Google. Implemented a flexible caching system with in-memory, file-based, and no-op cache options to improve modularity. Updated dependencies and revised the project structure for improved maintainability.

pkg/cache/memory.go

@@ -0,0 +1,78 @@
+package cache
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type memoryCache struct {
+	data map[string][]byte
+}
+
+var _ Cache = &memoryCache{}
+
+func NewMemoryCache() (Cache, error) {
+	return &memoryCache{
+		data: make(map[string][]byte),
+	}, nil
+}
+
+func (m *memoryCache) Get(key string, writer io.Writer) error {
+	data, ok := m.data[key]
+	if ok {
+		_, err := writer.Write(data)
+		return err
+	}
+
+	return ErrNotFound
+}
+
+func (m *memoryCache) GetString(key string) (string, error) {
+	data, ok := m.data[key]
+	if ok {
+		return string(data), nil
+	}
+
+	return "", ErrNotFound
+}
+
+func (m *memoryCache) GetJSON(key string, value interface{}) error {
+	data, ok := m.data[key]
+	if ok {
+		return json.Unmarshal(data, value)
+	}
+
+	return ErrNotFound
+}
+
+func (m *memoryCache) Set(key string, value io.Reader) error {
+	data, err := io.ReadAll(value)
+	if err != nil {
+		return err
+	}
+
+	m.data[key] = data
+
+	return nil
+}
+
+func (m *memoryCache) SetJSON(key string, value interface{}) error {
+	data, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+
+	m.data[key] = data
+
+	return nil
+}
+
+func (m *memoryCache) SetString(key string, value string) error {
+	m.data[key] = []byte(value)
+	return nil
+}
+
+func (m *memoryCache) Delete(key string) error {
+	delete(m.data, key)
+	return nil
+}

pkg/cache/nop.go

@@ -0,0 +1,38 @@
+package cache
+
+import (
+	"io"
+)
+
+type Nop struct {
+}
+
+var _ Cache = Nop{}
+
+func (Nop) Get(_ string, _ io.Writer) error {
+	return ErrNotFound
+}
+
+func (Nop) GetString(_ string) (string, error) {
+	return "", ErrNotFound
+}
+
+func (Nop) GetJSON(_ string, _ interface{}) error {
+	return ErrNotFound
+}
+
+func (Nop) Set(_ string, _ io.Reader) error {
+	return nil
+}
+
+func (Nop) SetJSON(_ string, _ interface{}) error {
+	return nil
+}
+
+func (Nop) SetString(_ string, _ string) error {
+	return nil
+}
+
+func (Nop) Delete(_ string) error {
+	return nil
+}

pkg/search/duckduckgo.go

@@ -0,0 +1,83 @@
+package search
+
+import (
+	"answer/pkg/cache"
+	"context"
+	"fmt"
+	"time"
+
+	"gitea.stevedudenhoeffer.com/steve/go-extractor"
+
+	"gitea.stevedudenhoeffer.com/steve/go-extractor/sites/duckduckgo"
+)
+
+type duckDuckGo struct {
+	Cache   cache.Cache
+	Browser extractor.Browser
+}
+
+func NewDuckDuckGo(c cache.Cache) (Search, error) {
+	timeout := 60 * time.Second
+	browser, err := extractor.NewPlayWrightBrowser(extractor.PlayWrightBrowserOptions{Timeout: &timeout})
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to create browser: %w", err)
+	}
+
+	return duckDuckGo{
+		Cache:   c,
+		Browser: browser,
+	}, nil
+}
+
+var _ Search = duckDuckGo{}
+
+func (d duckDuckGo) Search(ctx context.Context, search string) ([]Result, error) {
+	var res []Result
+
+	key := "duckduckgo:" + search
+
+	err := d.Cache.GetJSON(key, &res)
+
+	if err == nil {
+		return res, nil
+	}
+
+	results, err := d.searchDuckDuckGo(ctx, search)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, r := range results {
+		res = append(res, Result{
+			Title:       r.Title,
+			URL:         r.URL,
+			Description: r.Description,
+		})
+	}
+
+	_ = d.Cache.SetJSON(key, res)
+
+	return res, nil
+}
+
+func (d duckDuckGo) searchDuckDuckGo(ctx context.Context, search string) ([]Result, error) {
+	cfg := duckduckgo.DefaultConfig
+
+	r, err := cfg.Search(ctx, d.Browser, search)
+	if err != nil {
+		return nil, err
+	}
+
+	res := make([]Result, len(r))
+
+	for i, v := range r {
+		res[i] = Result{
+			URL:         v.URL,
+			Title:       v.Title,
+			Description: v.Description,
+		}
+	}
+
+	return res, nil
+}