util.go

package mobi

import (
	"strings"

	r "github.com/leotaku/mobi/records"
)

func chaptersToText(m Book) (string, []r.ChunkInfo, []r.ChapterInfo, error) {
	text := new(strings.Builder)
	chunks := make([]r.ChunkInfo, 0)
	chaps := make([]r.ChapterInfo, 0)
	if m.tpl == nil {
		m.tpl = defaultTemplate
	}

	chunkId := 0
	for chapId, chap := range m.Chapters {
		chapStart := text.Len()
		for _, chunk := range chap.Chunks {
			inv := newInventory(m, chap, chapId, chunkId)
			head, err := runTemplate(*m.tpl, inv)
			if err != nil {
				return "", nil, nil, err
			}
			chunks = append(chunks, r.ChunkInfo{
				PreStart:      text.Len(),
				PreLength:     len(head),
				ContentStart:  text.Len() + len(head),
				ContentLength: len(chunk.Body),
			})
			text.WriteString(head)
			text.WriteString(chunk.Body)
			chunkId++
		}
		chaps = append(chaps, r.ChapterInfo{
			Title:  chap.Title,
			Start:  chapStart,
			Length: text.Len() - chapStart,
		})
	}

	return text.String(), chunks, chaps, nil
}

func textToRecords(html string, chapters []r.ChapterInfo) []r.TextRecord {
	provider := r.NewTrailProvider(chapters)
	records := make([]r.TextRecord, 0)
	recordCount := len(html) / r.TextRecordMaxSize
	if len(html)%r.TextRecordMaxSize != 0 {
		recordCount++
	}

	for i := 0; i < recordCount; i++ {
		from := i * r.TextRecordMaxSize
		to := min(from+r.TextRecordMaxSize, len(html))
		trail := provider.Get(from, to)
		records = append(records, r.NewTextRecord(html[from:to], trail))
	}

	return records
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}