From 62e9a9a55f5af35d81b9349bba72f239105f251b Mon Sep 17 00:00:00 2001
From: Valentin Pratz <112951103+vpratz@users.noreply.github.com>
Date: Thu, 28 Mar 2024 00:20:14 +0100
Subject: [PATCH] Feature: add support for pre-commit (#56)

---
 .pre-commit-hooks.yaml  | 20 ++++++++++++++++++++
 Dockerfile              |  2 ++
 README.md               | 38 ++++++++++++++++++++++++++++++++++++++
 panvimdoc.pre-commit.sh | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 92 insertions(+)
 create mode 100644 .pre-commit-hooks.yaml
 create mode 100755 panvimdoc.pre-commit.sh

diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
new file mode 100644
index 0000000..937c77c
--- /dev/null
+++ b/.pre-commit-hooks.yaml
@@ -0,0 +1,20 @@
+- id: panvimdoc-docker
+  name: pandoc to vimdoc (docker)
+  description: Convert markdown documentation to vimdoc (using docker)
+  entry: /panvimdoc.pre-commit.sh
+  language: docker
+  files: ^README\.md$
+  args:
+    - '--input-file'
+    - README.md
+  pass_filenames: false
+- id: panvimdoc
+  name: pandoc to vimdoc
+  description: Convert markdown documentation to vimdoc (using local environment)
+  entry: panvimdoc.pre-commit.sh
+  language: script
+  files: ^README\.md$
+  args:
+    - '--input-file'
+    - README.md
+  pass_filenames: false
diff --git a/Dockerfile b/Dockerfile
index 0bd94ac..ffc9ca8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,11 +4,13 @@ RUN apk update && apk upgrade && apk add bash vim neovim
 
 # Copies your code file  repository to the filesystem
 COPY panvimdoc.sh /panvimdoc.sh
+COPY panvimdoc.pre-commit.sh /panvimdoc.pre-commit.sh
 COPY scripts/ /scripts/
 COPY lib/Demojify.lua /usr/share/lua/common/lib/Demojify.lua
 
 # change permission to execute the script and
 RUN chmod +x /panvimdoc.sh
+RUN chmod +x /panvimdoc.pre-commit.sh
 
 # file to execute when the docker container starts up
 ENTRYPOINT ["/panvimdoc.sh"]
diff --git a/README.md b/README.md
index e18e5a3..0c3b427 100644
--- a/README.md
+++ b/README.md
@@ -171,6 +171,44 @@ jobs:
 
 </details>
 
+### Using pre-commit
+[pre-commit](https://pre-commit.com/) lets you easily install and manage pre-commit hooks locally.
+
+Two hooks are available, differing only in the way dependencies are handled:
+
+- `panvimdoc-docker`: Requires a running Docker engine on your host. All other dependencies will be loaded inside the container.
+- `panvimdoc`: Runs in your local environment, so you have to make sure all dependencies of panvimdoc are installed
+    (i.e., `pandoc v3.0.0` or greater)
+
+To use a hook, first install pre-commit. Then, add the following to your `.pre-commit-config.yaml` (here `panvimdoc-docker` is used):
+
+```yaml
+- repo: 'https://github.com/kdheepak/panvimdoc'
+  rev: v4.0.1
+  hooks:
+    - id: panvimdoc-docker
+      args:
+        - '--project-name'
+        - <your-project-name>
+```
+
+You can specify additional arguments to `panvimdoc.sh` using `args`. See the section below (or run `./panvimdoc.sh`) for the full list of arguments.
+
+To change the input file, modify the `files` field of the hook and supply the corresponding `--input-file` to `args`. In the example below, the hook will be triggered if any `.md` file changes:
+
+```yaml
+- repo: 'https://github.com/kdhee'
+  rev: v4.0.1
+  hooks:
+    - id: panvimdoc-docker
+      files: ^.*\.md$
+      args:
+        - '--project-name'
+        - <your-project-name>
+        - '--input-file'
+        - <your-input-file.md>
+```
+
 ### Using it manually
 
 The `./panvimdoc.sh` script runs `pandoc` along with all the filters and custom output writer.
diff --git a/panvimdoc.pre-commit.sh b/panvimdoc.pre-commit.sh
new file mode 100755
index 0000000..02cac07
--- /dev/null
+++ b/panvimdoc.pre-commit.sh
@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+args=$#                          # number of command line args
+for (( i=1; i<=$args; i+=2 ))    # loop from 1 to N (where N is number of args)
+do
+    j=$((i + 1 ))
+    if [ "${!i}" == "--project-name" ] ; then
+        PROJECT_NAME="${!j}"
+        break;
+    fi
+done
+
+# extract project name to determine file location
+if [ -z "$PROJECT_NAME" ]; then
+    echo "Error: argument --project-name is not set."
+    exit 1
+fi
+# store hash to check whether documentation has changed
+if [ -f "doc/$PROJECT_NAME.txt" ]; then
+    DOC_HASH_PRE="$(md5sum doc/$PROJECT_NAME.txt)"
+else
+    DOC_HASH_PRE=""
+fi
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+source "$SCRIPT_DIR/panvimdoc.sh"
+DOC_HASH_POST="$(md5sum doc/$PROJECT_NAME.txt)"
+# send FAIL when doc has changed
+if [ "$DOC_HASH_PRE" != "$DOC_HASH_POST" ] ; then
+    echo ""
+    echo 'Updated documentation "doc/$PROJECT_NAME.txt"'
+    echo 'Use "git add doc/$PROJECT_NAME.txt" to stage the changes'
+    exit 1
+fi