1 files changed, 106 insertions, 0 deletions
diff --git a/gemini-to-web/src/gemini_to_web/html.py b/gemini-to-web/src/gemini_to_web/html.py
new file mode 100644
index 0000000..9594155
--- /dev/null
+++ b/gemini-to-web/src/gemini_to_web/html.py
@@ -0,0 +1,106 @@
+import typing
+
+import htmlgenerator
+from lxml import etree, html
+
+from gemini_to_web import parser
+
+
+def first_header_title_extractor(parsed: list[parser.GemElement]):
+    heading_lines = [element for element in parsed if isinstance(element, parser.HeadingLine)]
+    if heading_lines:
+        return heading_lines[0].heading_text
+
+
+def to_html(parsed: list[parser.GemElement], title_extractor=first_header_title_extractor):
+    body = []
+    building_element = None
+    building_content = None
+
+    def close(body, building_element, building_content):
+        if building_element and building_content:
+            body.append(building_element(*building_content))
+        return (body, None, None)
+
+    head = []
+
+    if title_extractor:
+       head.append(htmlgenerator.TITLE(title_extractor(parsed)))
+
+    for item in parsed:
+        match item:
+            case parser.HeadingLine(level, heading_text):
+                if building_element:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                headers = [htmlgenerator.H1, htmlgenerator.H2, htmlgenerator.H3]
+                body.append(headers[level-1](heading_text))
+            case parser.QuoteLine(text):
+                # https://geminiprotocol.net/docs/gemtext.gmi#blockquotes says:
+                #
+                # > The quoted content is written as a single long line [...]
+                if building_element:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                body.append(htmlgenerator.BLOCKQUOTE(text))
+            case parser.PreformattingToggleLine(alt_text):
+                if building_element == htmlgenerator.PRE:
+                    assert not alt_text, f"Closing preformatting toggle line with alt text {alt_text}"
+                    body, building_element, building_content = close(body, building_element, building_content)
+                else:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                    building_element = htmlgenerator.PRE
+                    building_content = ""
+            case parser.PreformattedTextLine(text):
+                assert building_element == htmlgenerator.PRE
+                building_content += text
+                building_content += "\n"
+            case parser.TextLine(""):
+                if building_element:
+                    body, building_element, building_content = close(body, building_element, building_content)
+            case parser.TextLine(text):
+                if building_element == htmlgenerator.P:
+                    building_content += [htmlgenerator.BR(), text]
+                    continue
+                elif building_element is not None and building_element != htmlgenerator.P:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                building_element = htmlgenerator.P
+                building_content = [text]
+            case parser.LinkLine(url, link_name):
+                if building_element == htmlgenerator.P:
+                    building_content += [htmlgenerator.BR(), htmlgenerator.A(link_name, href=url)]
+                    continue
+                elif building_element is not None and building_element != htmlgenerator.P:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                building_element = htmlgenerator.P
+                building_content = [htmlgenerator.A(link_name, href=url)]
+            case parser.ListItem(text):
+                if building_element == htmlgenerator.UL:
+                    building_content.append(htmlgenerator.LI(text))
+                    continue
+                elif building_element is not None and building_element != htmlgenerator.UL:
+                    body, building_element, building_content = close(body, building_element, building_content)
+                building_element = htmlgenerator.UL
+                building_content = [htmlgenerator.LI(text)]
+            case _:
+                assert False, f"unknown element {item}"
+
+    close(body, building_element, building_content)
+    html = htmlgenerator.HTML(
+        htmlgenerator.HEAD(*head),
+        htmlgenerator.BODY(*body),
+    )
+    return html
+
+
+def pretty(s):
+    return etree.tostring(html.fromstring(s), pretty_print=True).decode("utf8")
+
+
+def cli_to_html():
+    import sys
+    input_ = sys.stdin.read()
+    gemtext = parser.parse(input_)
+    gemtext = list(gemtext)
+    html = to_html(gemtext)
+    rendered = htmlgenerator.render(html, {})
+    rendered = pretty(rendered)
+    print(rendered)