From f4b3a08a371ff16003feac9a3f37c2c646b6f472 Mon Sep 17 00:00:00 2001
From: valentin gagarin <valentin.gagarin@tweag.io>
Date: Wed, 13 Nov 2024 15:24:41 +0100
Subject: [PATCH] implement collections

---
 content/default.nix             |  14 +-
 content/news/website-launch.nix |  19 +++
 default.nix                     |  13 +-
 lib.nix                         |  40 ++++++
 structure/default.nix           | 218 +++++++++++++++++++++++---------
 structure/types.nix             |  47 +++++++
 6 files changed, 286 insertions(+), 65 deletions(-)
 create mode 100644 content/news/website-launch.nix
 create mode 100644 lib.nix
 create mode 100644 structure/types.nix

diff --git a/content/default.nix b/content/default.nix
index 96871673..6f1a0e20 100644
--- a/content/default.nix
+++ b/content/default.nix
@@ -1,8 +1,6 @@
-{ config, ... }:
+{ config, lib, ... }:
 let
   inherit (config) pages;
-  files = dir:
-    map (name: dir + /${name}) (with builtins; attrNames (readDir dir));
 in
 {
   imports = [
@@ -10,7 +8,9 @@ in
     ./fediversity.nix
   ]
   ++
-  (files ./partners)
+  lib.fileset.toList ./partners
+  ++
+  lib.fileset.toList ./news
   ;
 
   pages.index = {
@@ -46,6 +46,12 @@ in
 
       [Read more about ${partner.title}](./${partner})
       '') (with pages; [ nlnet oid tweag nordunet ]))}
+
+      # News
+
+      ${lib.concatStringsSep "\n" (map (article: ''
+      - ${article.date} [${article.title}](./${article})
+      '') config.collections.news.entry)}
     '';
   };
 }
diff --git a/content/news/website-launch.nix b/content/news/website-launch.nix
new file mode 100644
index 00000000..ae79c073
--- /dev/null
+++ b/content/news/website-launch.nix
@@ -0,0 +1,19 @@
+{ ... }:
+{
+  collections.news.entry = {
+    title = "Fediversity website launch";
+    description = "Announcing our new website for the Fediversity project";
+    date = "2024-05-15";
+    author = "Laurens Hof";
+    locations = [
+      "website-launch.html"
+    ];
+    body = ''
+      We are pleased to introduce the launch of our new website dedicated to the Fediversity project.
+
+      The project is broad in scope, and the website reflects this. Whether you are a developer, an individual interested in the project, or want to know how the grant money is spend, the website keeps you up to date with everything you need to know.
+
+      We're excited to show you more of the progress of the Fediversity project, and how we can build a next generation of the open internet together!
+    '';
+  };
+}
diff --git a/default.nix b/default.nix
index 96b2a4be..be41a936 100644
--- a/default.nix
+++ b/default.nix
@@ -6,16 +6,23 @@
     overlays = [ ];
   }
 , lib ? import "${sources.nixpkgs}/lib"
-,
 }:
+let
+  lib' = final: prev: import ./lib.nix { lib = final; };
+  lib'' = lib.extend lib';
+in
 {
   build =
     let
-      result = pkgs.lib.evalModules {
+      result = lib''.evalModules {
         modules = [
           ./structure
           ./content
-          { _module.args = { inherit pkgs; }; }
+          {
+            _module.args = {
+              inherit pkgs;
+            };
+          }
         ];
       };
     in
diff --git a/lib.nix b/lib.nix
new file mode 100644
index 00000000..36ad68f1
--- /dev/null
+++ b/lib.nix
@@ -0,0 +1,40 @@
+{ lib }:
+rec {
+  /**
+    Create a URL-safe slug from any string
+  */
+  slug = str:
+    let
+      # Replace non-alphanumeric characters with hyphens
+      replaced = join ""
+        (
+          builtins.map
+            (c:
+              if (c >= "a" && c <= "z") || (c >= "0" && c <= "9")
+              then c
+              else "-"
+            )
+            (with lib; stringToCharacters (toLower str)));
+
+      # Remove leading and trailing hyphens
+      trimHyphens = s:
+        let
+          matched = builtins.match "(-*)([^-].*[^-]|[^-])(-*)" s;
+        in
+        with lib; optionalString (!isNull matched) (builtins.elemAt matched 1);
+
+      collapseHyphens = s:
+        let
+          result = builtins.replaceStrings [ "--" ] [ "-" ] s;
+        in
+        if result == s then s else collapseHyphens result;
+    in
+    trimHyphens (collapseHyphens replaced);
+
+  join = lib.concatStringsSep;
+
+  splitLines = s: with builtins; filter (x: !isList x) (split "\n" s);
+
+  indent = prefix: s:
+    join "\n" (map (x: if x == "" then x else "${prefix}${x}") (splitLines s));
+}
diff --git a/structure/default.nix b/structure/default.nix
index dc7780c4..4e9cdf0a 100644
--- a/structure/default.nix
+++ b/structure/default.nix
@@ -5,71 +5,130 @@ let
     types
     ;
   cfg = config;
+  types' = import ./types.nix { inherit lib; } // {
+    article = { config, collectionName, ... }: {
+      imports = [ types'.page ];
+      options = {
+        date = mkOption {
+          description = "Publication date";
+          type = with types; nullOr str;
+          default = null;
+        };
+        author = mkOption {
+          description = "Page author";
+          type = with types; nullOr (either str (listOf str));
+          default = null;
+        };
+      };
+      config.name = lib.slug config.title;
+      config.outPath = "${collectionName}/${lib.head config.locations}";
+      config.template = cfg.templates.article;
+    };
+
+    page = { name, config, ... }: {
+      options = {
+        name = mkOption {
+          description = "Symbolic name for the page, used as a human-readable identifier";
+          type = types.str;
+          default = name;
+        };
+        title = mkOption {
+          description = "Page title";
+          type = types.str;
+          default = name;
+        };
+        locations = mkOption {
+          description = ''
+            List of historic output locations for the resulting file
+
+            The first element is the canonical location.
+            All other elements are used to create redirects to the canonical location.
+          '';
+          type = with types; nonEmptyListOf str;
+        };
+        outPath = mkOption {
+          description = ''
+            Location of the page, used for transparently creating links
+          '';
+          type = types.str;
+          default = lib.head config.locations;
+        };
+        description = mkOption {
+          description = ''
+            One-sentence description of page contents
+          '';
+          type = types.str;
+        };
+        summary = mkOption {
+          description = ''
+            One-paragraph summary of page contents
+          '';
+          type = types.str;
+        };
+        body = mkOption {
+          description = ''
+            Page contents in CommonMark
+          '';
+          type = types.str;
+        };
+        template = mkOption
+          {
+            description = ''
+              Function that converts the page contents to files
+            '';
+            type = with types; functionTo (functionTo options.files.type);
+            default = cfg.templates.page;
+          };
+      };
+    };
+  };
 in
 {
+  # TODO: split out:
+  # - extra module system types into lib'
+  # - page and article types into their own module values under structure/${page,article}.nix
+  #   yes, actually. those types should probably be configurable
+  config.collections.news.type = types'.article;
+
   options.pages = mkOption {
     description = ''
       Collection of pages on the site
     '';
-    type = with types; attrsOf (submodule ({ name, config, ... }:
-      {
-        options = {
-          title = mkOption {
-            type = types.str;
-          };
-          locations = mkOption {
-            description = ''
-              List of historic output locations for the resulting file
+    type = with types; attrsOf (submodule types'.page);
+  };
 
-              The first element is the canonical location.
-              All other elements are used to create redirects to the canonical location.
-            '';
-            type = with types; nonEmptyListOf str;
+  options.collections = mkOption
+    {
+      description = ''
+        Named collections of unnamed pages
+      '';
+      type = with types; attrsOf (submodule ({ name, config, ... }: {
+        options = {
+          type = mkOption {
+            description = "Type of entries in the collection";
+            type = types.deferredModule;
           };
-          outPath = mkOption {
-            description = ''
-              Canonical location of the page
-            '';
-            type = types.str;
-            default = lib.head config.locations;
+          entry = mkOption {
+            description = "An entry in the collection";
+            type = types'.collection (types.submodule ({
+              _module.args.collection = config.entry;
+              _module.args.collectionName = name;
+              imports = [ config.type ];
+            }));
           };
-          description = mkOption {
-            description = ''
-              One-sentence description of page contents
-            '';
-            type = types.str;
-          };
-          summary = mkOption {
-            description = ''
-              One-paragraph summary of page contents
-            '';
-            type = types.str;
-          };
-          body = mkOption {
-            description = ''
-              Page contents in CommonMark
-            '';
-            type = types.str;
-          };
-          template = mkOption
-            {
-              description = ''
-                Function that converts the page contents to files
-              '';
-              type = with types; functionTo (functionTo (functionTo options.files.type));
-              default = cfg.templates.default;
-            };
         };
       }));
-  };
+    };
 
   options.templates = mkOption {
     description = ''
       Collection of named functions to convert page contents to files
+
+      Each template function takes the complete site `config` and the page data structure.
     '';
-    type = with types; attrsOf (functionTo (functionTo (functionTo options.files.type)));
+    type = with types; attrsOf (functionTo (functionTo options.files.type));
   };
-  config.templates.default =
+  config.templates =
     let
       commonmark = name: markdown: pkgs.runCommand "${name}.html"
         {
@@ -78,10 +137,10 @@ in
         cmark ${builtins.toFile "${name}.md" markdown} > $out
       '';
     in
-    lib.mkDefault
-      (config: name: page: {
-        # TODO: create static redirects from the tail
-        ${lib.head page.locations} = builtins.toFile "${name}.html" ''
+    {
+      page = lib.mkDefault (config: page: {
+        # TODO: create static redirects from `tail page.locations`
+        ${page.outPath} = builtins.toFile "${page.name}.html" ''
           <html>
           <head>
           <meta charset="utf-8" />
@@ -90,14 +149,39 @@ in
 
           <title>${page.title}</title>
           <meta name="description" content="${page.description}" />
-          <link rel="canonical" href="${lib.head page.locations}" />
+          <link rel="canonical" href="${page.outPath}" />
           </head>
           <body>
-          ${builtins.readFile (commonmark name page.body)}
+          ${lib.indent "  " (builtins.readFile (commonmark page.name page.body))}
           <body>
           </html>
         '';
       });
+      article = lib.mkDefault (config: page: {
+        # TODO: create static redirects from `tail page.locations`
+        ${page.outPath} = builtins.toFile "${page.name}.html" ''
+          <html>
+          <head>
+          <meta charset="utf-8" />
+          <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+          <meta name="viewport" content="width=device-width, initial-scale=1" />
+
+          <title>${page.title}</title>
+          <meta name="description" content="${page.description}" />
+          ${with lib;
+            if ! isNull page.author then
+            ''<meta name="author" content="${if isList page.author then join ", " page.author else page.author}" />''
+            else ""
+          }
+          <link rel="canonical" href="${page.outPath}" />
+          </head>
+          <body>
+          ${lib.indent "  " (builtins.readFile (commonmark page.name page.body))}
+          <body>
+          </html>
+        '';
+      });
+    };
 
   options.files = mkOption {
     description = ''
@@ -108,9 +192,27 @@ in
     '';
     type = with types; attrsOf path;
   };
-  config.files = lib.concatMapAttrs
-    (name: page: page.template config name page)
-    config.pages;
+  config.files =
+    let
+      pages = lib.concatMapAttrs
+        (name: page: page.template config page)
+        config.pages;
+      collections =
+        let
+          byCollection = with lib; mapAttrs
+            (_: collection:
+              map (entry: entry.template config entry) collection.entry
+            )
+            config.collections;
+        in
+        with lib; concatMapAttrs
+          (collection: entries:
+            foldl' (acc: entry: acc // entry) { } entries
+          )
+          byCollection;
+    in
+    pages // collections;
+
 
   options.build = mkOption {
     description = ''
@@ -121,7 +223,7 @@ in
       let
         script = ''
           mkdir $out
-        '' + lib.concatStringsSep "\n" copy;
+        '' + lib.join "\n" copy;
         copy = lib.mapAttrsToList
           (
             path: file: ''
diff --git a/structure/types.nix b/structure/types.nix
new file mode 100644
index 00000000..8a27cc53
--- /dev/null
+++ b/structure/types.nix
@@ -0,0 +1,47 @@
+{ lib, ... }:
+let
+  inherit (lib) types;
+in
+rec {
+  collection = elemType:
+    let
+      unparenthesize = class: class == "noun";
+      desc = type:
+        types.optionDescriptionPhrase unparenthesize type;
+      desc' = type:
+        let
+          typeDesc = types.optionDescriptionPhrase unparenthesize type;
+        in
+        if type.descriptionClass == "noun"
+        then
+          typeDesc + "s"
+        else
+          "many instances of ${typeDesc}";
+    in
+    types.mkOptionType {
+      name = "collection";
+      description = "separately specified ${desc elemType} for a collection of ${desc' elemType}";
+      merge = loc: defs:
+        map
+          (def:
+            let
+              merged = lib.mergeDefinitions
+                (loc ++ [ "[definition ${toString def.file}]" ])
+                elemType
+                [{ inherit (def) file; value = def.value; }];
+            in
+            if merged ? mergedValue then merged.mergedValue else merged.value
+          )
+          defs;
+      check = elemType.check;
+      getSubOptions = elemType.getSubOptions;
+      getSubModules = elemType.getSubModules;
+      substSubModules = m: collection (elemType.substSubModules m);
+      functor = (lib.defaultFunctor "collection") // {
+        type = collection;
+        wrapped = elemType;
+        payload = { };
+      };
+      nestedTypes.elemType = elemType;
+    };
+}