Add support for footnotes

n2y/plugins/footnotes.py

@@ -0,0 +1,58 @@
+import re
+
+from pandoc.types import Note, Str, Para
+
+from n2y.rich_text import TextRichText
+from n2y.blocks import ParagraphBlock
+
+
+class ParagraphWithFootnoteBlock(ParagraphBlock):
+    def __init__(self, client, notion_data, page, get_children=True):
+        super().__init__(client, notion_data, page, get_children)
+        self._attach_footnote_data_if_exists()
+
+    def to_pandoc(self):
+        return None if self._is_footnote() else super().to_pandoc()
+
+    def _attach_footnote_data_if_exists(self):
+        if self._is_footnote():
+            if "footnotes" not in self.client.plugin_data:
+                self.client.plugin_data["footnotes"] = {}
+            self.client.plugin_data["footnotes"][self._footnote()] = self._footnote_ast()
+
+    def _is_footnote(self):
+        return self._footnote() is not None
+
+    def _footnote(self):
+        first_str = self.rich_text.to_plain_text().split(" ")[0]
+        footnotes = re.findall(r"\[(\d+)\]:", first_str)
+        if len(footnotes) != 1:
+            return None
+        return footnotes[0]
+
+    def _footnote_ast(self):
+        ast = super().to_pandoc()
+        return Para(ast[0][2:]) if not isinstance(ast, list) else [Para(ast[0][0][2:])] + ast[1:]
+
+
+class TextRichTextWithFootnoteRef(TextRichText):
+    def to_pandoc(self):
+        pandoc_ast = []
+        for token in super().to_pandoc():
+            if not isinstance(token, Str):
+                pandoc_ast.append(token)
+                continue
+            refs = re.findall(r"\[\^(\d+)\]", token[0])
+            if len(refs) != 1:
+                pandoc_ast.append(token)
+                continue
+            block = self.client.plugin_data["footnotes"][refs[0]]
+            footnote = Note(block) if isinstance(block, list) else Note([block])
+            pandoc_ast.append(footnote)
+        return pandoc_ast
+
+
+notion_classes = {
+    "blocks": {"paragraph": ParagraphWithFootnoteBlock},
+    "rich_texts": {"text": TextRichTextWithFootnoteRef},
+}