Create Index(Output) class and migrate index generation from Site

Like previous Content refactor, this allows validating file collisions
in the discover/write build pipeline.

omicron/ssg/output/__init__.py

@@ -1,6 +1,7 @@
 from omicron.ssg.output.output import Output
 from omicron.ssg.output.content import Content, ContentError
 from omicron.ssg.output.factory import create_content, is_content
+from omicron.ssg.output.index import Index, discover_index
 from omicron.ssg.output.memory import Memory
 
 __all__ = [
@@ -9,5 +10,7 @@ __all__ = [
     "ContentError",
     "create_content",
     "is_content",
+    "Index",
+    "discover_index",
     "Memory",
 ]

omicron/ssg/output/index.py

@@ -0,0 +1,97 @@
+import logging
+from math import ceil
+from itertools import batched
+from typing import TYPE_CHECKING, Literal
+from omicron.ssg.output.output import Output
+from omicron.ssg.output.content import Content
+
+log = logging.getLogger(__name__)
+
+if TYPE_CHECKING:
+    from omicron.ssg.site import Site  # for static checking with mypy
+else:
+    Site = "omicron.ssg.site.Site"  # for runtime checking with beartype
+
+
+class Index(Output):
+    def __init__(
+        self,
+        kind: Literal["root", "section", "tag"],
+        items: list[Content],
+        page_num: int,
+        total_pages: int,
+        label: str | None,
+    ):
+        super().__init__(Index.build_uri(kind, page_num, label))
+        self.kind = kind
+        self.items = items
+        self.page_num = page_num
+        self.total_pages = total_pages
+        self.label = label
+
+    @staticmethod
+    def build_uri(
+        kind: Literal["root", "section", "tag"],
+        page_num: int,
+        label: str | None,
+    ) -> str:
+        if page_num == 1:
+            file = "index.html"
+        else:
+            file = f"page-{page_num}.html"
+
+        if kind == "root":
+            uri = file
+        elif kind == "section":
+            assert label, "label can't be None if kind is not root"
+            uri = f"{label}/{file}"
+        else:
+            assert label, "label can't be None if kind is not root"
+            uri = f"tags/{label}/{file}"
+        return uri
+
+    def write(self, site: Site) -> None:
+        template = site.jinja_env.get_template("index.html")
+        html = template.render(
+            site=site,
+            items=self.items,
+            page_num=self.page_num,
+            total_pages=self.total_pages,
+            kind=self.kind,
+            label=self.label,
+        )
+        dest = site.output_path / self.uri
+        dest.parent.mkdir(parents=True, exist_ok=True)
+        dest.write_text(html, encoding="utf-8")
+        log.debug("Wrote %s", dest)
+
+
+def make_index_pages(
+    items: list[Content],
+    kind: Literal["root", "section", "tag"],
+    label: str | None,
+    items_per_page: int,
+) -> list[Index]:
+    sorted_items = sorted(items, key=lambda c: c.created, reverse=True)
+    if not sorted_items:
+        log.warning(
+            "No content for %s index%s, generating empty page",
+            kind,
+            f" ({label})" if label else "",
+        )
+        return [Index(kind, [], 1, 1, label)]
+    num_pages = ceil(len(sorted_items) / items_per_page)
+    return [
+        Index(kind, list(page_items), i + 1, num_pages, label)
+        for i, page_items in enumerate(batched(sorted_items, items_per_page))
+    ]
+
+
+def discover_index(site: Site) -> list[Index]:
+    outputs: list[Index] = []
+    outputs.extend(make_index_pages(site.content, "root", None, site.items_per_page))
+    for section, items in site.by_section.items():
+        outputs.extend(make_index_pages(items, "section", section, site.items_per_page))
+    for tag, items in site.by_tag.items():
+        outputs.extend(make_index_pages(items, "tag", tag, site.items_per_page))
+    return outputs

omicron/ssg/site.py

@@ -1,8 +1,6 @@
 import logging
 from typing import Any, cast
 from urllib.parse import urlparse
-from itertools import batched
-from math import ceil
 
 from omicron.ssg.output import (
     Output,
@@ -11,6 +9,7 @@ from omicron.ssg.output import (
     is_content,
     create_content,
     Memory,
+    discover_index,
 )
 from omicron.ssg.markdown import highlight_style
 
@@ -118,51 +117,11 @@ class Site:
                 self.add_by_tag(content)
                 self.content.append(content)
         self.update_tags_by_count()
+        for index in discover_index(self):
+            self.add_by_uri(index)
+            self.other_outputs.append(index)
         log.info("Discovered %d content items", len(self.content))
 
-    def render_single_index_page(
-        self,
-        out_dir: Path,
-        items: tuple[Content, ...],
-        page_num: int,
-        total_pages: int,
-        section: str | None,
-        tag: str | None = None,
-    ) -> None:
-        template = self.jinja_env.get_template("index.html")
-        html = template.render(
-            site=self,
-            items=items,
-            page_num=page_num,
-            total_pages=total_pages,
-            section=section,
-            tag=tag,
-        )
-        out_file = out_dir / f"page-{page_num}.html"
-        out_file.write_text(html, encoding="utf-8")
-
-    def render_index_pages(
-        self,
-        items: list[Content],
-        out_dir: Path,
-        section: str | None,
-        tag: str | None = None,
-    ) -> None:
-        out_dir.mkdir(parents=True, exist_ok=True)
-        if not items:
-            log.warning("No content, generating empty index page")
-            self.render_single_index_page(out_dir, (), 1, 1, section, tag)
-        else:
-            num_pages = ceil(len(items) / self.items_per_page)
-            for i, page_items in enumerate(batched(items, self.items_per_page)):
-                self.render_single_index_page(
-                    out_dir, page_items, i + 1, num_pages, section, tag
-                )
-        index = out_dir / "index.html"
-        if index.exists() or index.is_symlink():
-            index.unlink()
-        index.symlink_to("page-1.html")
-
     def render_tags_page(self) -> None:
         template = self.jinja_env.get_template("tags.html")
         html = template.render(site=self, tags=self.tags_by_count)
@@ -170,19 +129,6 @@ class Site:
         tags_dir.mkdir(parents=True, exist_ok=True)
         (tags_dir / "index.html").write_text(html, encoding="utf-8")
 
-    def render_indices(self) -> None:
-        sorted_all = sorted(self.content, key=lambda c: c.created, reverse=True)
-        self.render_index_pages(sorted_all, self.output_path, None)
-        for section, items in self.by_section.items():
-            sorted_items = sorted(items, key=lambda c: c.created, reverse=True)
-            self.render_index_pages(sorted_items, self.output_path / section, section)
-        for tag, items in self.by_tag.items():
-            sorted_items = sorted(items, key=lambda c: c.created, reverse=True)
-            self.render_index_pages(
-                sorted_items, self.output_path / "tags" / tag, None, tag
-            )
-        self.render_tags_page()
-
     def build(self) -> None:
         if not self.origin:
             log.warning(
@@ -195,6 +141,6 @@ class Site:
         self.output_path.mkdir(parents=True, exist_ok=True)
         for content in self.content:
             content.write(self)
-        self.render_indices()
+        self.render_tags_page()
         for output in self.other_outputs:
             output.write(self)

omicron/ssg/templates/plain/index.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
-{% set prefix = (section + "/") if section else (("tags/" + tag + "/") if tag else "") %}
+{% set prefix = (label + "/") if kind == "section" else (("tags/" + label + "/") if kind == "tag" else "") %}
-{% set heading = section or tag or "" %}
+{% set heading = label or "" %}
 
 {% block title %}{% if heading %}{{ heading }} — {% endif %}{{ site.name }}{% if page_num > 1 %} — Page {{ page_num }}{% endif %}{% endblock %}
 
@@ -10,16 +10,16 @@
 {% endblock %}
 
 {% block breadcrumb %}
-{% if section %}
+{% if kind == "section" %}
 <nav aria-label="breadcrumb">
     <a href="{{ site.base_dir }}">{{ site.name }}</a> ›
-    {{ section }}
+    {{ label }}
 </nav>
-{% elif tag %}
+{% elif kind == "tag" %}
 <nav aria-label="breadcrumb">
     <a href="{{ site.base_dir }}">{{ site.name }}</a> ›
     <a href="{{ site.base_dir }}tags/">Tags</a> ›
-    {{ tag }}
+    {{ label }}
 </nav>
 {% else %}
 {{ super() }}
@@ -40,11 +40,11 @@
 {% if total_pages > 1 %}
 <nav>
     {% if page_num > 1 %}
-    <a href="{{ site.base_dir }}{{ prefix }}page-{{ page_num - 1 }}.html">← Newer</a>
+    <a href="{{ site.base_dir }}{{ prefix }}{{ "" if page_num - 1 == 1 else "page-" ~ (page_num - 1) ~ ".html" }}">← Newer</a>
     {% endif %}
     {% for p in range(1, total_pages + 1) %}
     {% if p == page_num %}<strong>{{ p }}</strong>
-    {% else %}<a href="{{ site.base_dir }}{{ prefix }}page-{{ p }}.html">{{ p }}</a>
+    {% else %}<a href="{{ site.base_dir }}{{ prefix }}{{ "" if p == 1 else "page-" ~ p ~ ".html" }}">{{ p }}</a>
     {% endif %}
     {% endfor %}
     {% if page_num < total_pages %}