1 files changed, 293 insertions, 0 deletions
diff --git a/article/article.go b/article/article.go
new file mode 100644
index 0000000..0a219a1
--- /dev/null
+++ b/article/article.go
@@ -0,0 +1,293 @@
+package article
+
+import (
+	"bufio"
+	"database/sql"
+	"errors"
+	"html"
+	"io"
+	"os"
+	"path"
+	"regexp"
+	"strings"
+	"time"
+
+	"code.laria.me/laria.me/dbutils"
+	"code.laria.me/laria.me/markdown"
+)
+
+var (
+	ErrBrokenHeader            = errors.New("The article header is broken")
+	ErrMissingMandatoryHeaders = errors.New("The article header is missing some mandatory headers")
+)
+
+type Article struct {
+	Slug        string
+	Published   time.Time
+	Hidden      bool
+	Title       string
+	SummaryHtml string
+	FullHtml    string
+	Tags        map[string]struct{}
+}
+
+var reHtmlTag = regexp.MustCompile(`<([^>'"]+|'[^']*'|"[^"]*")*>`)
+var reHtmlEntity = regexp.MustCompile(`&[^;]*;`)
+
+func stripTags(s string) string {
+	s = reHtmlTag.ReplaceAllString(s, "")
+	s = reHtmlEntity.ReplaceAllStringFunc(s, html.UnescapeString)
+	return s
+}
+
+func (a Article) updateDbDetails(tx *sql.Tx, id int64) error {
+	_, err := tx.Exec(`
+		UPDATE article SET
+			published = ?,
+			hidden = ?,
+			title = ?,
+			summary_html = ?,
+			full_html = ?,
+			full_plain = ?
+		WHERE article_id = ?
+	`, a.Published.Format("2006-01-02 15:04:05"), a.Hidden, a.Title, a.SummaryHtml, a.FullHtml, stripTags(a.FullHtml), id)
+
+	return err
+}
+
+func (a Article) createInDb(tx *sql.Tx) (int64, error) {
+	res, err := tx.Exec(`
+		INSERT INTO article SET
+			slug = ?,
+			published = ?,
+			hidden = ?,
+			title = ?,
+			summary_html = ?,
+			full_html = ?,
+			full_plain = ?
+	`, a.Slug, a.Published.Format("2006-01-02 15:04:05"), a.Hidden, a.Title, a.SummaryHtml, a.FullHtml, stripTags(a.FullHtml))
+
+	if err != nil {
+		return 0, err
+	}
+
+	return res.LastInsertId()
+}
+
+func removeTags(tx *sql.Tx, id int64) error {
+	_, err := tx.Exec(`DELETE FROM article_tag WHERE article_id = ?`, id)
+	return err
+}
+
+func setTags(tx *sql.Tx, id int64, tags map[string]struct{}) error {
+	stmt, err := tx.Prepare(`REPLACE INTO article_tag SET article_id = ?, tag = ?`)
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+
+	for tag := range tags {
+		if _, err = stmt.Exec(id, tag); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (a Article) saveToDb(tx *sql.Tx) (int64, error) {
+	var id int64
+	switch err := tx.QueryRow(`SELECT article_id FROM article WHERE slug = ?`, a.Slug).Scan(&id); err {
+	case nil:
+		if err = a.updateDbDetails(tx, id); err != nil {
+			return 0, err
+		}
+	case sql.ErrNoRows:
+		id, err = a.createInDb(tx)
+		if err != nil {
+			return 0, err
+		}
+	default:
+		return 0, err
+	}
+
+	if err := removeTags(tx, id); err != nil {
+		return 0, err
+	}
+
+	if err := setTags(tx, id, a.Tags); err != nil {
+		return 0, err
+	}
+
+	return id, nil
+}
+
+func (a Article) SaveToDb(db *sql.DB) (int64, error) {
+	tx, err := db.Begin()
+	if err != nil {
+		return 0, err
+	}
+
+	id, err := a.saveToDb(tx)
+	err = dbutils.TxCommitIfOk(tx, err)
+	return id, err
+}
+
+func DeleteArticlesFromDbExcept(db *sql.DB, slugs []string) error {
+	if len(slugs) == 0 {
+		return nil
+	}
+
+	query := new(strings.Builder)
+	query.WriteString("DELETE FROM article WHERE slug NOT IN (?")
+
+	for i := 1; i < len(slugs); i++ { // intentionally starting at 1, since the first '?' is already there
+		query.WriteString(",?")
+	}
+
+	query.WriteString(")")
+
+	slugsAsInterfaces := make([]interface{}, 0, len(slugs))
+	for _, slug := range slugs {
+		slugsAsInterfaces = append(slugsAsInterfaces, interface{}(slug))
+	}
+
+	_, err := db.Exec(query.String(), slugsAsInterfaces...)
+	return err
+}
+
+func splitTags(s string) map[string]struct{} {
+	tags := make(map[string]struct{})
+
+	parts := strings.Split(s, ",")
+	for _, part := range parts {
+		tag := strings.TrimSpace(part)
+		if tag != "" {
+			tags[tag] = struct{}{}
+		}
+	}
+
+	return tags
+}
+
+func parseDate(s string) (time.Time, error) {
+	return time.Parse("2006-01-02 15:04:05", s)
+}
+
+func parseHeader(scanner *bufio.Scanner) (Article, error) {
+	var article Article
+	var err error
+
+	seenTitle := false
+	seenPublished := false
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		line = strings.TrimSpace(line)
+
+		if line == "" {
+			break
+		}
+
+		parts := strings.SplitN(line, ":", 2)
+		if len(parts) != 2 {
+			return Article{}, ErrBrokenHeader
+		}
+
+		key := strings.ToLower(strings.TrimSpace(parts[0]))
+		value := strings.TrimSpace(parts[1])
+
+		switch key {
+		case "title":
+			article.Title = value
+			seenTitle = true
+		case "tags":
+			article.Tags = splitTags(value)
+		case "date":
+			if article.Published, err = parseDate(value); err != nil {
+				return Article{}, err
+			}
+			seenPublished = true
+		case "hidden":
+			article.Hidden = strings.ToLower(value) == "yes"
+		}
+	}
+
+	if err = scanner.Err(); err != nil {
+		return Article{}, err
+	}
+
+	if !seenTitle || !seenPublished {
+		return Article{}, ErrMissingMandatoryHeaders
+	}
+
+	return article, nil
+}
+
+var reMore = regexp.MustCompile(`^\s*~~+(?i:more)~~+\s*$`)
+
+func parseText(scanner *bufio.Scanner, article *Article) error {
+	var err error
+
+	builder := new(strings.Builder)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if reMore.MatchString(line) {
+			if article.SummaryHtml, err = markdown.Parse(builder.String()); err != nil {
+				return err
+			}
+
+			continue
+		}
+
+		builder.WriteString(line)
+		builder.WriteRune('\n')
+	}
+
+	if err = scanner.Err(); err != nil {
+		return err
+	}
+
+	if article.FullHtml, err = markdown.Parse(builder.String()); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func ParseArticle(r io.Reader) (Article, error) {
+	var article Article
+
+	scanner := bufio.NewScanner(r)
+	article, err := parseHeader(scanner)
+	if err != nil {
+		return Article{}, err
+	}
+
+	if err = parseText(scanner, &article); err != nil {
+		return Article{}, err
+	}
+
+	return article, nil
+}
+
+func LoadArticle(filename string) (Article, error) {
+	parts := strings.Split(path.Base(filename), ".")
+	slug := strings.Join(parts[:len(parts)-1], ".")
+
+	f, err := os.Open(filename)
+	if err != nil {
+		return Article{}, err
+	}
+	defer f.Close()
+
+	article, err := ParseArticle(f)
+	if err != nil {
+		return Article{}, err
+	}
+
+	article.Slug = slug
+	return article, nil
+}