Rewrite relative links

pyproject.toml

@@ -1,14 +1,13 @@
 [build-system]
 build-backend = "hatchling.build"
-requires = ["hatchling<2"]
+requires = ["hatchling<2", "hatch-fancy-pypi-readme"]
 
 [project]
 name = "pymc-marketing"
 description = "Marketing Statistical Models in PyMC"
 requires-python = ">=3.10"
-readme = "README.md"
 license = { file = "LICENSE" }
-dynamic = ["version"]
+dynamic = ["version", "readme"]
 maintainers = [{ name = "PyMC Labs", email = "[email protected]" }]
 classifiers = [
     "Development Status :: 5 - Production/Stable",
@@ -97,8 +96,29 @@ packages = [
 [tool.hatch.version]
 path = "pymc_marketing/version.py"
 
-[tool.setuptools.dynamic]
-version = { file = "pymc_marketing/version.txt" }
+# <https://github.com/hynek/hatch-fancy-pypi-readme>
+[tool.hatch.metadata.hooks.fancy-pypi-readme]
+content-type = "text/markdown"
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.fragments]]
+path = "README.md"
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.substitutions]]
+# Image links should go to the raw content on GitHub
+# <https://stackoverflow.com/a/46875147>
+pattern = '\[(.*?)\]\(((?!https?://)\S+\.(png|jpe?g|svg|gif))\)'
+replacement = '[\1](https://raw.githubusercontent.com/pymc-labs/pymc-marketing/main/\g<2>)'
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.substitutions]]
+# Handle also HTML image tags
+pattern = '''(<img\b[^>]*\bsrc=)(['"])((?!https?://)[^'"]+)(['"][^>]*>)'''
+replacement = '<img src="https://raw.githubusercontent.com/pymc-labs/pymc-marketing/main/\g<3>\g<4>'
+
+[[tool.hatch.metadata.hooks.fancy-pypi-readme.substitutions]]
+# Remaining non-image relative links map to the normal absolute GitHub URL
+# <https://stackoverflow.com/a/46875147>
+pattern = '\[(.*?)\]\(((?!https?://)\S+)\)'
+replacement = '[\1](https://github.com/pymc-labs/pymc-marketing/tree/main/\g<2>)'
 
 [project.urls]
 repository = "https://github.com/pymc-labs/pymc-marketing"