Move internal packages to an internal folder

For reference: https://go.dev/doc/go1.4#internalpackages

internal/reader/atom/atom_03.go

@@ -0,0 +1,178 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package atom // import "miniflux.app/v2/internal/reader/atom"
+
+import (
+	"encoding/base64"
+	"html"
+	"strings"
+	"time"
+
+	"miniflux.app/v2/internal/crypto"
+	"miniflux.app/v2/internal/logger"
+	"miniflux.app/v2/internal/model"
+	"miniflux.app/v2/internal/reader/date"
+	"miniflux.app/v2/internal/reader/sanitizer"
+	"miniflux.app/v2/internal/url"
+)
+
+// Specs: http://web.archive.org/web/20060811235523/http://www.mnot.net/drafts/draft-nottingham-atom-format-02.html
+type atom03Feed struct {
+	ID      string        `xml:"id"`
+	Title   atom03Text    `xml:"title"`
+	Author  atomPerson    `xml:"author"`
+	Links   atomLinks     `xml:"link"`
+	Entries []atom03Entry `xml:"entry"`
+}
+
+func (a *atom03Feed) Transform(baseURL string) *model.Feed {
+	var err error
+
+	feed := new(model.Feed)
+
+	feedURL := a.Links.firstLinkWithRelation("self")
+	feed.FeedURL, err = url.AbsoluteURL(baseURL, feedURL)
+	if err != nil {
+		feed.FeedURL = feedURL
+	}
+
+	siteURL := a.Links.originalLink()
+	feed.SiteURL, err = url.AbsoluteURL(baseURL, siteURL)
+	if err != nil {
+		feed.SiteURL = siteURL
+	}
+
+	feed.Title = a.Title.String()
+	if feed.Title == "" {
+		feed.Title = feed.SiteURL
+	}
+
+	for _, entry := range a.Entries {
+		item := entry.Transform()
+		entryURL, err := url.AbsoluteURL(feed.SiteURL, item.URL)
+		if err == nil {
+			item.URL = entryURL
+		}
+
+		if item.Author == "" {
+			item.Author = a.Author.String()
+		}
+
+		if item.Title == "" {
+			item.Title = sanitizer.TruncateHTML(item.Content, 100)
+		}
+
+		if item.Title == "" {
+			item.Title = item.URL
+		}
+
+		feed.Entries = append(feed.Entries, item)
+	}
+
+	return feed
+}
+
+type atom03Entry struct {
+	ID       string     `xml:"id"`
+	Title    atom03Text `xml:"title"`
+	Modified string     `xml:"modified"`
+	Issued   string     `xml:"issued"`
+	Created  string     `xml:"created"`
+	Links    atomLinks  `xml:"link"`
+	Summary  atom03Text `xml:"summary"`
+	Content  atom03Text `xml:"content"`
+	Author   atomPerson `xml:"author"`
+}
+
+func (a *atom03Entry) Transform() *model.Entry {
+	entry := new(model.Entry)
+	entry.URL = a.Links.originalLink()
+	entry.Date = a.entryDate()
+	entry.Author = a.Author.String()
+	entry.Hash = a.entryHash()
+	entry.Content = a.entryContent()
+	entry.Title = a.entryTitle()
+	return entry
+}
+
+func (a *atom03Entry) entryTitle() string {
+	return sanitizer.StripTags(a.Title.String())
+}
+
+func (a *atom03Entry) entryContent() string {
+	content := a.Content.String()
+	if content != "" {
+		return content
+	}
+
+	summary := a.Summary.String()
+	if summary != "" {
+		return summary
+	}
+
+	return ""
+}
+
+func (a *atom03Entry) entryDate() time.Time {
+	dateText := ""
+	for _, value := range []string{a.Issued, a.Modified, a.Created} {
+		if value != "" {
+			dateText = value
+			break
+		}
+	}
+
+	if dateText != "" {
+		result, err := date.Parse(dateText)
+		if err != nil {
+			logger.Error("atom: %v", err)
+			return time.Now()
+		}
+
+		return result
+	}
+
+	return time.Now()
+}
+
+func (a *atom03Entry) entryHash() string {
+	for _, value := range []string{a.ID, a.Links.originalLink()} {
+		if value != "" {
+			return crypto.Hash(value)
+		}
+	}
+
+	return ""
+}
+
+type atom03Text struct {
+	Type     string `xml:"type,attr"`
+	Mode     string `xml:"mode,attr"`
+	CharData string `xml:",chardata"`
+	InnerXML string `xml:",innerxml"`
+}
+
+func (a *atom03Text) String() string {
+	content := ""
+
+	switch {
+	case a.Mode == "xml":
+		content = a.InnerXML
+	case a.Mode == "escaped":
+		content = a.CharData
+	case a.Mode == "base64":
+		b, err := base64.StdEncoding.DecodeString(a.CharData)
+		if err == nil {
+			content = string(b)
+		}
+	default:
+		content = a.CharData
+	}
+
+	if a.Type != "text/html" {
+		content = html.EscapeString(content)
+	}
+
+	return strings.TrimSpace(content)
+}