Implement note guid

export.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"unicode"
 )
@@ -30,7 +31,8 @@ const (
 	mankidownTag = "mankidown"
 
 	// Anki Import UI wants each note type field to be non empty. We allow
-	// empty fields and add emptyComment in order to fill with something
+	// empty fields in markdown and add emptyComment in order to fill the fields
+	// with something
 	emptyComment = "<!---->"
 )
 
@@ -75,11 +77,11 @@ func (ex *Exporter) Export(notes *Notes) error {
 	ex.appendHeaderColumns(out, notes.FieldNames())
 	ex.appendHeaderTags(out, inFile)
 
-	for _, note := range notes.Notes {
+	for i, note := range notes.Notes {
 
 		// 1 field) id
 		fields := []string{}
-		fields = append(fields, ex.buildIdField(note, outFile))
+		fields = append(fields, ex.buildIdField(note, i, outFile))
 
 		// 2 field) tags
 		fields = append(fields, buildTagsField(note))
@@ -149,13 +151,17 @@ func (ex *Exporter) appendHeaderTags(out io.Writer, inFile string) {
 	fmt.Fprintf(out, HeaderTags, strings.Join(tags, " "))
 }
 
-func (ex *Exporter) buildIdField(n *Note, outFile string) string {
+func (ex *Exporter) buildIdField(n *Note, i int, outFile string) string {
+
+	if n.hasGuid() {
+		return n.Guid()
+	}
 
 	if ex.config.GuidPrefix != "" {
-		return ex.config.GuidPrefix + n.Id()
+		return ex.config.GuidPrefix + strconv.Itoa(i)
 	}
 
-	return outFile + n.Id()
+	return outFile + strconv.Itoa(i)
 }
 
 // buildTagsField builds the Tags string for a note

parse.go

@@ -3,7 +3,6 @@ package mankidown
 import (
 	"bytes"
 	"fmt"
-	"strconv"
 	"strings"
 
 	"github.com/yuin/goldmark"
@@ -12,19 +11,23 @@ import (
 	"github.com/yuin/goldmark/text"
 )
 
+// guidPrefix is the tag prefix that, if present in the H1 header,  determines
+// the guid of the note
+const guidPrefix = "guid:"
+
 type Parser struct {
 	mdp goldmark.Markdown
 }
 
-// A Field contains the parsed html content inside a H2 Heading element
+// Field contains the parsed html content inside a H2 Heading element
 type Field struct {
 	Html string
 }
 
 // A Note contains parsed mardown html that will be mapped to a anki note type
 // field in the output file
 type Note struct {
-	id     string
+	guid   string
 	tags   []string
 	fields []Field
 }
@@ -36,8 +39,12 @@ func newNote() *Note {
 	}
 }
 
-func (n *Note) Id() string {
-	return n.id
+func (n *Note) Guid() string {
+	return n.guid
+}
+
+func (n *Note) hasGuid() bool {
+	return n.guid != ""
 }
 
 func (n *Note) Fields() []Field {
@@ -60,14 +67,18 @@ func (n *Note) addTags(tags string) {
 
 	words := strings.Fields(tags)
 
-	n.tags = append(n.tags, words...)
-}
+	for _, w := range words {
+		// guid
+		if strings.HasPrefix(w, guidPrefix) {
+			n.guid = strings.TrimPrefix(w, guidPrefix)
+			continue
+		}
 
-func (n *Note) addId(id string) {
-	n.id = id
+		n.tags = append(n.tags, w)
+	}
 }
 
-// A Notes contains the parsed notes elements
+// Notes contains the parsed notes elements
 type Notes struct {
 	Notes      []*Note
 	fieldNames []string
@@ -103,8 +114,16 @@ func (n *Notes) validateNote(nt *Note) error {
 		return fmt.Errorf("invalid number of fields in note %d (want %d, have %d)", n.numNotes()+1, n.numFieds(), nt.numFieds())
 	}
 
-	if nt.Id() == "" {
-		return fmt.Errorf("no notes declared at the start by parsing note %d", n.numNotes()+1)
+	if n.numNotes() > 0 {
+		if n.hasGuids() != nt.hasGuid() {
+			return fmt.Errorf("guid mismatch for note %d", n.numNotes()+1)
+		}
+	}
+
+	if nt.hasGuid() {
+		if n.hasGuid(nt.guid) {
+			return fmt.Errorf("guid %q in note %d already exists", nt.Guid(), n.numNotes()+1)
+		}
 	}
 
 	return nil
@@ -118,6 +137,37 @@ func (n *Notes) numNotes() int {
 	return len(n.Notes)
 }
 
+// hasGuids returns true if the document notes have guids. As we do not allow
+// notes in the markdown with and without guids at the same time, just checking
+// one is enough
+func (n *Notes) hasGuids() bool {
+	if n.numNotes() == 0 {
+		return false
+	}
+
+	if n.Notes[0].Guid() == "" {
+		return false
+	}
+
+	return true
+}
+
+// hasGuid return true if one of the Note of Notes has the same guid as guid.
+func (n *Notes) hasGuid(guid string) bool {
+
+	if n.numNotes() == 0 {
+		return false
+	}
+
+	for _, note := range n.Notes {
+		if note.Guid() == guid {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (ns *Notes) addFieldName(fieldName string) error {
 
 	// after first note:
@@ -189,10 +239,6 @@ func (p *Parser) Parse(markdown []byte) (*Notes, error) {
 				nt.addTags(tags)
 			}
 
-			// note guid suffix
-			noteNum := len(notes.Notes) + 1
-			nt.addId(strconv.Itoa(noteNum))
-
 			return ast.WalkSkipChildren, nil
 		}
 

parse_test.go

@@ -262,3 +262,61 @@ func TestParseNoFieldsAfterNote(t *testing.T) {
 		t.Errorf("\ngot %s\nwant Error", err)
 	}
 }
+
+func TestParseNotesWithAndWithoutGuids(t *testing.T) {
+
+	WithAndWithout := []byte(`# note1 tag1 guid:note1
+## field1 
+
+First note has two fields, Field1 and Field2
+
+## field2 
+
+text
+
+# note2 tag2 noguid
+## 
+
+text
+
+## 
+
+Text`)
+
+	md := mankidown.NewParser()
+	_, err := md.Parse(WithAndWithout)
+
+	t.Logf("Error is %q", err)
+	if err == nil {
+		t.Errorf("\ngot %s\nwant Error", err)
+	}
+}
+
+func TestParseNotesWithDuplicateGuid(t *testing.T) {
+
+	WithAndWithout := []byte(`# note1 tag1 guid:note1
+## field1 
+
+First note has two fields, Field1 and Field2
+
+## field2 
+
+text
+
+# note2 tag2 guid:note1
+## 
+
+text
+
+## 
+
+Text`)
+
+	md := mankidown.NewParser()
+	_, err := md.Parse(WithAndWithout)
+
+	t.Logf("Error is %q", err)
+	if err == nil {
+		t.Errorf("\ngot %s\nwant Error", err)
+	}
+}