feat: implemented the "css mixin" command

Justfile

@@ -1,3 +1,5 @@
+export DEBUG := "*"
+
 @default:
     just --choose
 
@@ -17,7 +19,8 @@ colors: format
 
 # Generate examples/theme.css
 examples: format
-    priduck-color-theme build \
+    node src/cli.mjs css mixin \
+        --selector :root \
         --output examples/theme.css \
         --light examples/light.css \
         --light-more-contrast examples/light-more-contrast.css \

README.md

@@ -22,7 +22,37 @@ Once installed, this will produce a CLI in the `node_modules/.bin` folder called
 
 ## Commands
 
-### "css variables [--hue HUE] [--output PATH] [--selector SELECTOR]"
+### css mixin
+
+Combines a number of CSS style fragments together and intersperses them in a manner that supports `prefers-color-scheme` and `prefers-contrast` in the various methods to support no preferences or a preference in one or more of the options.
+
+For purposes of the read me file, an example of use has to suffice.
+
+```shell
+priduck css mixin --selector :root --output examples/theme.css --light examples/light.css --light-more-contrast examples/light-more-contrast.css --light-less-contrast examples/light-less-contrast.css --dark examples/dark.css --dark-more-contrast examples/dark-more-contrast.css --dark-less-contrast examples/dark-less-contrast.css
+```
+
+If a fragment isn't included, then it isn't used. So to generate an output file that defaults to dark mode and honors `prefers-color-scheme`, the command
+
+```shell
+priduck css mixin --selector :root --output examples/theme.css --light examples/light.css --dark examples/dark.css --output style.css
+```
+
+The fragment files can either be a bare set of CSS properties, or they can use a pseudo-selector of `:theme`.
+
+```css
+:theme {
+  color: red;
+}
+```
+
+```css
+color: red;
+```
+
+There is no parsing of CSS, so this can also be used with Sass or Less or Postcss.
+
+### css variables [--hue HUE] [--output PATH] [--selector SELECTOR]
 
 Generate a CSS file using variables. The thirty colors all follow the pattern of `--color-priduck-cXbY` where `X` is a number between 0 and 9 (inclusive) and `Y` is the brightness (also in the range of 0 to 9, inclusive).
 
@@ -44,7 +74,7 @@ If `--selector` is included, the colors will be wrapped in a selector and slight
 }
 ```
 
-### "palette gpl --hue HUE [--output PATH] [--secondary 5] [--tertiary 8]"
+### palette gpl --hue HUE [--output PATH] [--secondary 5] [--tertiary 8]
 
 Generate a GNU Imp or Inkscape file. `--hue` is required in this situation. This assumes up to two additional colors (secondary, and tertiary).
 

examples/dark-less-contrast.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 0, 7;
+  background-color: var(--color-priduck-c0b0);
+  color: var(--color-priduck-c0b7);
 }

examples/dark-more-contrast.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 0, 9;
+  background-color: var(--color-priduck-c0b0);
+  color: var(--color-priduck-c0b9);
 }

examples/dark.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 0, 8;
+  background-color: var(--color-priduck-c0b0);
+  color: var(--color-priduck-c0b8);
 }

examples/light-less-contrast.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 9, 2;
+  background-color: var(--color-priduck-c0b9);
+  color: var(--color-priduck-c0b2);
 }

examples/light-more-contrast.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 9, 0;
+  background-color: var(--color-priduck-c0b9);
+  color: var(--color-priduck-c0b0);
 }

examples/light.css

@@ -1,3 +1,4 @@
 :theme {
-  @mixin theme 9, 1;
+  background-color: var(--color-priduck-c0b9);
+  color: var(--color-priduck-c0b1);
 }

examples/style.css

@@ -1,2 +1,2 @@
 @import url("../colors.css");
-@import url("../theme.css");
+@import url("./theme.css");

package.json

@@ -18,7 +18,6 @@
     "priduck": "./src/cli.mjs"
   },
   "dependencies": {
-    "@priduck-color-theme/cli": "^0.0.1",
     "colorjs.io": "^0.5.0",
     "debug": "^4.3.4",
     "mkdirp": "^3.0.1",

src/cmds/css.mjs

@@ -1,10 +1,11 @@
 import * as variablesCmd from "./css/variables.mjs";
+import * as mixinCmd from "./css/mixin.mjs";
 
 export const command = "css";
 export const desc = "Generate CSS files";
 
 export function builder(yargv) {
-  yargv.command(variablesCmd).demand(2);
+  yargv.command(variablesCmd).command(mixinCmd).demand(2);
 }
 
 export function handler(argv) {}

src/cmds/css/mixin.mjs

@@ -0,0 +1,231 @@
+import { write } from "../../output.mjs";
+import debug from "debug";
+import * as fs from "fs";
+
+/** @type {object} */
+const log = debug("css").extend("mixin");
+
+export const command = "mixin";
+export const desc =
+  "Generate a CSS file that mixes in various prefers-* selectors";
+
+export function builder(argv) {
+  argv
+    .option("o", {
+      alias: "output",
+      describe: "The output path for colors.css",
+      type: "string",
+    })
+    .option("s", {
+      alias: "selector",
+      describe: "The CSS selector to wrap the colors",
+      demandOption: true,
+      type: "string",
+    })
+    .option("default", {
+      type: "string",
+      choices: ["light", "dark"],
+      default: "light",
+      describe: "The default theme if none are provided",
+    })
+    .option("light", {
+      type: "string",
+      describe: "The path to CSS that provides the base light theme",
+    })
+    .option("light-more-contrast", {
+      type: "string",
+      describe: "The path to CSS that provides more contrast for light theme",
+    })
+    .option("light-less-contrast", {
+      type: "string",
+      describe: "The path to CSS that provides less contrast for light theme",
+    })
+    .option("dark", {
+      type: "string",
+      describe: "The path to CSS that provides the base dark theme",
+    })
+    .option("dark-more-contrast", {
+      type: "string",
+      describe: "The path to CSS that provides more contrast for dark theme",
+    })
+    .option("dark-less-contrast", {
+      type: "string",
+      describe: "The path to CSS that provides less contrast for dark theme",
+    });
+}
+
+export async function handler(argv) {
+  // We like some noise.
+  log("generating CSS mixin file");
+
+  // Load in all the files.
+  const light = load(argv, "light");
+  const lightMoreContrast = load(argv, "light-more-contrast");
+  const lightLessContrast = load(argv, "light-less-contrast");
+  const dark = load(argv, "dark");
+  const darkMoreContrast = load(argv, "dark-more-contrast");
+  const darkLessContrast = load(argv, "dark-less-contrast");
+
+  // Figure out the default.
+  const auto = argv.default === "light" ? light : dark;
+
+  const autoMoreContrast =
+    argv.default === "light" ? lightMoreContrast : darkMoreContrast;
+
+  const autoLessContrast =
+    argv.default === "light" ? lightLessContrast : darkLessContrast;
+
+  // Build up the components of the style.
+  let lines = [
+    block(argv, argv.selector, auto),
+    block(argv, '[data-prefers-contrast="more"]', autoMoreContrast),
+    block(argv, '[data-prefers-contrast="less"]', autoLessContrast),
+    media(
+      argv,
+      "@media (prefers-color-scheme: light)",
+      block(argv, argv.selector, light),
+      block(argv, '[data-prefers-contrast="more"]', lightMoreContrast),
+      block(argv, '[data-prefers-contrast="less"]', lightLessContrast),
+    ),
+    media(
+      argv,
+      "@media (prefers-color-scheme: dark)",
+      block(argv, argv.selector, dark),
+      block(argv, '[data-prefers-contrast="more"]', darkMoreContrast),
+      block(argv, '[data-prefers-contrast="less"]', darkLessContrast),
+    ),
+    block(argv, '[data-prefers-color-scheme="light"]', light),
+    block(
+      argv,
+      '[data-prefers-color-scheme="light"][data-prefers-contrast="more"]',
+      lightMoreContrast,
+    ),
+    block(
+      argv,
+      '[data-prefers-color-scheme="light"][data-prefers-contrast="less"]',
+      lightLessContrast,
+    ),
+    block(argv, '[data-prefers-color-scheme="dark"]', dark),
+    block(
+      argv,
+      '[data-prefers-color-scheme="dark"][data-prefers-contrast="more"]',
+      darkMoreContrast,
+    ),
+    block(
+      argv,
+      '[data-prefers-color-scheme="dark"][data-prefers-contrast="less"]',
+      darkLessContrast,
+    ),
+  ].flat();
+
+  // Write out the results to the console or a file.
+  await write(argv, lines);
+}
+
+/**
+ * Generates a number of CSS blocks.
+ *
+ * @param argv The arguments.
+ * @param {string} selector The CSS selector to put in.
+ * @param {string[]} lines The text to put inside the block.
+ */
+function media(argv, selector, ...lines) {
+  // If we have a blank line, then we don't want to write the section.
+  lines = lines.flat();
+
+  if (!lines || !lines[0]) {
+    return "";
+  }
+
+  // We include the selector, which is either a @media query or the user's
+  // selector. If we have a @media selector, we want to add the user's selector
+  // as the inner block.
+  let blockLines = [`${selector} {`];
+
+  // Insert all the lines while indenting them.
+  for (const line of lines) {
+    blockLines.push(`  ${line}`);
+  }
+
+  // Finish up the blocks.
+  blockLines.push(`}`);
+
+  return blockLines;
+}
+
+/**
+ * Generates a number of CSS blocks.
+ *
+ * @param argv The arguments.
+ * @param {string} selector The CSS selector to put in.
+ * @param {string[]} lines The text to put inside the block.
+ */
+function block(argv, selector, ...lines) {
+  // If we have a blank line, then we don't want to write the section.
+  lines = lines.flat();
+
+  if (!lines || !lines[0]) {
+    return "";
+  }
+
+  // We include the selector, which is either a @media query or the user's
+  // selector. If we have a @media selector, we want to add the user's selector
+  // as the inner block.
+  let blockLines = [`${selector} {`];
+
+  // Insert the lines with a little indent.
+  for (const line of lines) {
+    blockLines.push(`  ${line}`);
+  }
+
+  // Finish up the blocks.
+  blockLines.push(`}`);
+
+  return blockLines;
+}
+
+/**
+ * Loads a CSS file and removes the pseudo-selector, :theme.
+ *
+ * @param {object} argv
+ * @param {string} key
+ * @returns {string | undefined}
+ */
+function load(argv, key) {
+  // See if we have a file to load.
+  const value = argv[key];
+
+  if (!value || value.trim() === "") {
+    log(`no value provided for --${key}`);
+
+    return undefined;
+  }
+
+  // Load the file into memory so we can format it.
+  log(`reading --${key}=${argv[key]}`);
+
+  let text = fs.readFileSync(argv[key]).toString().replace(/\r\n/g, "\n");
+  const hasThemeSelector = text.match(/^\s*:theme/);
+
+  // If we have a theme selector, we need to get rid of it and the trailing
+  // brace but leave any whitespace in front of the line so we can outdent
+  // each of the characters.
+  if (hasThemeSelector) {
+    text = text.replace(/^\s*:theme\s*{\s*\n/, "").replace(/\s*}\s*$/, "");
+  }
+
+  // If we only have one line, then trim it and return it.
+  const lines = text.split("\n");
+
+  if (lines.length <= 1) {
+    return [lines[0].trim()];
+  }
+
+  // Otherwise, remove the whitespace in front of each of the lines so the
+  // resulting CSS is "prettier".
+  const prefix = lines[0].replace(/^(\s*).*$/, "$1");
+  const replace = new RegExp(`^${prefix}`);
+  const normalized = lines.map((line) => line.replace(replace, ""));
+
+  return normalized;
+}

src/cmds/css/variables.mjs

@@ -5,7 +5,7 @@ import debug from "debug";
 /** @type {object} */
 const log = debug("css").extend("variables");
 
-export const command = "variables [path.css]";
+export const command = "variables";
 export const desc = "Generate a CSS file that uses variables to generate";
 
 export function builder(argv) {