chore: add post ID -> attachment mapping

This will be used for #68

src/wp2hugo/internal/wpparser/wp_parser_setup.go

@@ -30,45 +30,6 @@ func NewParser() *Parser {
 	return &Parser{}
 }
 
-type WebsiteInfo struct {
-	Title       string
-	Link        string
-	Description string
-
-	PubDate  *time.Time
-	Language string
-
-	Categories []CategoryInfo
-	Tags       []TagInfo
-
-	// Collecting attachments is mostly useless but we are doing it for completeness
-	// Only the ones that are actually used in posts/pages are useful
-	Attachments     []AttachmentInfo
-	Pages           []PageInfo
-	Posts           []PostInfo
-	NavigationLinks []NavigationLink
-	CustomPosts     []CustomPostInfo
-}
-
-type NavigationLink struct {
-	// Fallback to Label if title is empty
-	Title string
-	URL   string
-	Type  string
-}
-
-type CategoryInfo struct {
-	ID       string
-	Name     string
-	NiceName string
-}
-
-type TagInfo struct {
-	ID   string
-	Name string
-	Slug string
-}
-
 type PublishStatus string
 
 // See some discussion here https://github.com/ashishb/wp2hugo/issues/26
@@ -97,6 +58,10 @@ type CommonFields struct {
 	PostFormat       *string
 	PostType         *string // Custom post types, typically FAQ, portfolio, etc.
 
+	// 1. Only attachments seem to have this
+	// 2. "0" seems to be reserved for no parent, we replace that with nil
+	PostParentID *string // ID of the parent post, if any
+
 	Description string // how to use this?
 	Content     string
 	Excerpt     string // may be empty
@@ -283,6 +248,8 @@ func (p *Parser) getWebsiteInfo(feed *rss.Feed, authors []string) (*WebsiteInfo,
 		Posts:           posts,
 		CustomPosts:     customPosts,
 		NavigationLinks: navigationLinks,
+
+		postIDToAttachmentCache: getPostIDToAttachmentsMap(attachments),
 	}
 	log.Info().
 		Int("numAttachments", len(websiteInfo.Attachments)).
@@ -391,6 +358,16 @@ func getCommonFields(item *rss.Item) (*CommonFields, error) {
 		postType = &item.Extensions["wp"]["post_type"][0].Value
 	}
 
+	var postParent *string
+	tmp := item.Extensions["wp"]["post_parent"][0].Value
+	if tmp != "0" && tmp != "" {
+		log.Debug().
+			Str("link", item.Link).
+			Str("post_parent", tmp).
+			Msg("Item has a parent")
+		postParent = &tmp
+	}
+
 	return &CommonFields{
 		Author:           getAuthor(item),
 		PostID:           item.Extensions["wp"]["post_id"][0].Value,
@@ -402,6 +379,7 @@ func getCommonFields(item *rss.Item) (*CommonFields, error) {
 		PublishStatus:    PublishStatus(publishStatus),
 		PostFormat:       postFormat,
 		PostType:         postType,
+		PostParentID:     postParent,
 		Excerpt:          item.Extensions["excerpt"]["encoded"][0].Value,
 
 		Description:     item.Description,

src/wp2hugo/internal/wpparser/wp_website_info.go

@@ -0,0 +1,64 @@
+package wpparser
+
+import (
+	"time"
+)
+
+type WebsiteInfo struct {
+	Title       string
+	Link        string
+	Description string
+
+	PubDate  *time.Time
+	Language string
+
+	Categories []CategoryInfo
+	Tags       []TagInfo
+
+	// Collecting attachments is mostly useless but we are doing it for completeness
+	// Only the ones that are actually used in posts/pages are useful
+	Attachments     []AttachmentInfo
+	Pages           []PageInfo
+	Posts           []PostInfo
+	NavigationLinks []NavigationLink
+	CustomPosts     []CustomPostInfo
+
+	postIDToAttachmentCache map[string][]AttachmentInfo
+}
+type NavigationLink struct {
+	// Fallback to Label if title is empty
+	Title string
+	URL   string
+	Type  string
+}
+
+type CategoryInfo struct {
+	ID       string
+	Name     string
+	NiceName string
+}
+
+type TagInfo struct {
+	ID   string
+	Name string
+	Slug string
+}
+
+func (w *WebsiteInfo) GetAttachmentsForPost(postID string) []AttachmentInfo {
+	return w.postIDToAttachmentCache[postID]
+}
+
+func getPostIDToAttachmentsMap(attachments []AttachmentInfo) map[string][]AttachmentInfo {
+	result := make(map[string][]AttachmentInfo)
+	for _, attachment := range attachments {
+		if attachment.PostParentID == nil {
+			continue
+		}
+		parentID := *attachment.PostParentID
+		if result[parentID] == nil {
+			result[parentID] = make([]AttachmentInfo, 0, 1)
+		}
+		result[parentID] = append(result[parentID], attachment)
+	}
+	return result
+}