refactored ebook preparation, separated from calling the pager

cmd/prepare.go

@@ -0,0 +1,119 @@
+/*
+Copyright © 2025 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/alecthomas/repr"
+	"github.com/tlinden/epuppy/pkg/epub"
+)
+
+func Prepare(conf *Config) (*Ebook, error) {
+	switch filepath.Ext(conf.Document) {
+	case ".epub":
+		return PrepareEpub(conf)
+	default:
+		return PrepareText(conf)
+	}
+}
+
+func PrepareText(conf *Config) (*Ebook, error) {
+	data, err := os.ReadFile(conf.Document)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Ebook{
+		Config: conf,
+		Title:  conf.Document,
+		Body:   string(data),
+	}, nil
+}
+
+func PrepareEpub(conf *Config) (*Ebook, error) {
+	book, err := epub.Open(conf.Document, conf.XML)
+	if err != nil {
+		return nil, err
+	}
+
+	if conf.Debug {
+		repr.Println("book.Files()")
+		repr.Println(book.Files())
+		repr.Println(book.Ncx)
+		repr.Println(book.Sections)
+		repr.Println(book.Opf.Manifest)
+	}
+
+	buf := strings.Builder{}
+	head := strings.Builder{}
+
+	for _, creator := range book.Opf.Metadata.Creator {
+		head.WriteString(creator.Data)
+		head.WriteString(" ")
+	}
+
+	head.WriteString("- ")
+
+	for _, title := range book.Opf.Metadata.Title {
+		head.WriteString(title)
+		head.WriteString(" ")
+	}
+
+	fetchByContent(conf, &buf, book)
+
+	return &Ebook{
+		Config:    conf,
+		Title:     head.String(),
+		Body:      buf.String(),
+		Cover:     book.CoverImage,
+		MediaType: book.CoverMediaType,
+	}, nil
+}
+
+func fetchByContent(conf *Config, buf *strings.Builder, book *epub.Book) bool {
+	chapter := 1
+	var gotbody bool
+
+	for _, content := range book.Content {
+		if len(content.Body) > 0 {
+			if content.Title != "" {
+				buf.WriteString(conf.Colors.Chapter.
+					Render(fmt.Sprintf("──────┤ %s ├──────", content.Title)))
+
+			}
+			buf.WriteString("\r\n\r\n")
+
+			if conf.Dump {
+				// avoid excess whitespaces when printing to stdout
+				buf.WriteString(content.Body)
+			} else {
+				buf.WriteString(conf.Colors.Body.Render(content.Body))
+			}
+
+			buf.WriteString("\r\n\r\n\r\n\r\n")
+			chapter++
+
+			gotbody = true
+		}
+	}
+
+	return gotbody
+}