From f446ad3114d3439fffca5a94e2b6f11c035fdb55 Mon Sep 17 00:00:00 2001
From: Johannes Rothe <mail@johannes-rothe.de>
Date: Tue, 3 Jan 2023 22:20:34 +0100
Subject: [PATCH] Add automatic note sync

---
 roles/dotfiles/files/bin/git-sync             | 384 ++++++++++++++++++
 roles/dotfiles/tasks/main.yml                 |  26 ++
 .../systemd/note-sync/note-sync.service.j2    |   8 +
 .../systemd/note-sync/note-sync.timer.j2      |   8 +
 4 files changed, 426 insertions(+)
 create mode 100755 roles/dotfiles/files/bin/git-sync
 create mode 100644 roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.service.j2
 create mode 100644 roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.timer.j2

diff --git a/roles/dotfiles/files/bin/git-sync b/roles/dotfiles/files/bin/git-sync
new file mode 100755
index 0000000..c8dbfb5
--- /dev/null
+++ b/roles/dotfiles/files/bin/git-sync
@@ -0,0 +1,384 @@
+#!/usr/bin/env bash
+#
+# git-sync
+#
+# synchronize tracking repositories
+#
+# 2012-20 by Simon Thum and contributors
+# Licensed as: CC0
+#
+# This script intends to sync via git near-automatically
+# in "tracking" repositories where a nice history is not
+# crucial, but having one at all is.
+#
+# Unlike the myriad of scripts to do just that already available,
+# it follows the KISS principle: It is small, requires nothing but
+# git and bash, but does not even try to shield you from git.
+#
+# Mode sync (default)
+#
+# Sync will likely get from you from a dull normal git repo with trivial
+# changes to an updated dull normal git repo equal to origin. No more,
+# no less. The intent is to do everything that's needed to sync
+# automatically, and resort to manual intervention as soon
+# as something non-trivial occurs. It is designed to be safe
+# in that it will likely refuse to do anything not known to
+# be safe.
+#
+# Mode check
+#
+# Check only performs the basic checks to make sure the repository
+# is in an orderly state to continue syncing, i.e. committing
+# changes, pull etc. without losing any data. When check returns
+# 0, sync can start immediately. This does not, however, indicate
+# that syncing is at all likely to succeed.
+
+# command used to auto-commit file modifications
+DEFAULT_AUTOCOMMIT_CMD="git add -u ; git commit -m \"%message\";"
+
+# command used to auto-commit all changes
+ALL_AUTOCOMMIT_CMD="git add -A ; git commit -m \"%message\";"
+
+# default commit message substituted into autocommit commands
+DEFAULT_AUTOCOMMIT_MSG="changes from $(uname -n) on $(date)"
+
+
+# AUTOCOMMIT_CMD="echo \"Please commit or stash pending changes\"; exit 1;"
+# TODO mode for stash push & pop
+
+print_usage() {
+    cat << EOF
+usage: $0 [-h] [-n] [-s] [MODE]
+
+Synchronize the current branch to a remote backup
+MODE may be either "sync" (the default) or "check", to verify that the branch is ready to sync
+
+OPTIONS:
+   -h      Show this message
+   -n      Commit new files even if branch.\$branch_name.syncNewFiles isn't set
+   -s      Sync the branch even if branch.\$branch_name.sync isn't set
+EOF
+}
+sync_new_files_anyway="false"
+sync_anyway="false"
+
+while getopts "hns" opt ; do
+    case $opt in
+        h )
+            print_usage
+            exit 0
+            ;;
+        n )
+            sync_new_files_anyway="true"
+            ;;
+        s )
+            sync_anyway="true"
+            ;;
+    esac
+done
+shift $((OPTIND-1))
+
+#
+#    utility functions, some adapted from git bash completion
+#
+
+__log_msg()
+{
+    echo git-sync: $1
+}
+
+# echo the git dir
+__gitdir()
+{
+	if [ "true" = "$(git rev-parse --is-inside-work-tree "$PWD" | head -1)" ]; then
+		git rev-parse --git-dir "$PWD" 2>/dev/null
+	fi
+}
+
+# echos repo state
+git_repo_state ()
+{
+	local g="$(__gitdir)"
+	if [ -n "$g" ]; then
+		if [ -f "$g/rebase-merge/interactive" ]; then
+			echo "REBASE-i"
+		elif [ -d "$g/rebase-merge" ]; then
+			echo "REBASE-m"
+		else
+			if [ -d "$g/rebase-apply" ]; then
+				echo "AM/REBASE"
+			elif [ -f "$g/MERGE_HEAD" ]; then
+				echo "MERGING"
+			elif [ -f "$g/CHERRY_PICK_HEAD" ]; then
+				echo "CHERRY-PICKING"
+			elif [ -f "$g/BISECT_LOG" ]; then
+				echo "BISECTING"
+			fi
+		fi
+		if [ "true" = "$(git rev-parse --is-inside-git-dir 2>/dev/null)" ]; then
+			if [ "true" = "$(git rev-parse --is-bare-repository 2>/dev/null)" ]; then
+				echo "|BARE"
+			else
+				echo "|GIT_DIR"
+			fi
+		elif [ "true" = "$(git rev-parse --is-inside-work-tree 2>/dev/null)" ]; then
+			git diff --no-ext-diff --quiet --exit-code || echo "|DIRTY"
+#			if [ -n "${GIT_PS1_SHOWSTASHSTATE-}" ]; then
+#			        git rev-parse --verify refs/stash >/dev/null 2>&1 && s="$"
+#			fi
+#
+#			if [ -n "${GIT_PS1_SHOWUNTRACKEDFILES-}" ]; then
+#			   if [ -n "$(git ls-files --others --exclude-standard)" ]; then
+#			      u="%"
+#			   fi
+#			fi
+#
+#			if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
+#				__git_ps1_show_upstream
+#			fi
+		fi
+	else
+	    echo "NOGIT"
+	fi
+}
+
+# check if we only have untouched, modified or (if configured) new files
+check_initial_file_state()
+{
+    local syncNew="$(git config --get --bool branch.$branch_name.syncNewFiles)"
+    if [[ "true" == "$syncNew" || "true" == "$sync_new_files_anyway" ]]; then
+	# allow for new files
+	if [ ! -z "$(git status --porcelain | grep -E '^[^ \?][^M\?] *')" ]; then
+	    echo "NonNewOrModified"
+	fi
+    else
+	# also bail on new files
+	if [ ! -z "$(git status --porcelain | grep -E '^[^ ][^M] *')" ]; then
+	    echo "NotOnlyModified"
+	fi
+    fi
+}
+
+# look for local changes
+# used to decide if autocommit should be invoked
+local_changes()
+{
+    if [ ! -z "$(git status --porcelain | grep -E '^(\?\?|[MARC] |[ MARC][MD])*')" ]; then
+	echo "LocalChanges"
+    fi
+}
+
+# determine sync state of repository, i.e. how the remote relates to our HEAD
+sync_state()
+{
+    local count="$(git rev-list --count --left-right $remote_name/$branch_name...HEAD)"
+
+    case "$count" in
+	"") # no upstream
+	    echo "noUpstream"
+	    false
+	    ;;
+	"0	0")
+	    echo "equal"
+	    true
+	    ;;
+	"0	"*)
+	    echo "ahead"
+	    true
+	    ;;
+	*"	0")
+	    echo "behind"
+	    true
+	    ;;
+	*)
+	    echo "diverged"
+	    true
+	    ;;
+    esac
+}
+
+# exit, issue warning if not in sync
+exit_assuming_sync() {
+    if [ "equal" == "$(sync_state)" ] ; then
+	__log_msg "In sync, all fine."
+	exit 0;
+    else
+	__log_msg "Synchronization FAILED! You should definitely check your repository carefully!"
+	__log_msg "(Possibly a transient network problem? Please try again in that case.)"
+	exit 3
+    fi
+}
+
+#
+#        Here git-sync actually starts
+#
+
+# first some sanity checks
+rstate="$(git_repo_state)"
+if [[ -z "$rstate" || "|DIRTY" = "$rstate" ]]; then
+    __log_msg "Preparing. Repo in $(__gitdir)"
+elif [[ "NOGIT" = "$rstate" ]] ; then
+    __log_msg "No git repository detected. Exiting."
+    exit 128 # matches git's error code
+else
+    __log_msg "Git repo state considered unsafe for sync: $(git_repo_state)"
+    exit 2
+fi
+
+# determine the current branch (thanks to stackoverflow)
+branch_name=$(git symbolic-ref -q HEAD)
+branch_name=${branch_name##refs/heads/}
+
+if [ -z "$branch_name" ] ; then
+    __log_msg "Syncing is only possible on a branch."
+    git status
+    exit 2
+fi
+
+# while at it, determine the remote to operate on
+remote_name=$(git config --get branch.$branch_name.pushRemote)
+if [ -z "$remote_name" ] ; then
+    remote_name=$(git config --get remote.pushDefault)
+fi
+if [ -z "$remote_name" ] ; then
+    remote_name=$(git config --get branch.$branch_name.remote)
+fi
+
+if [ -z "$remote_name" ] ; then
+    __log_msg "the current branch does not have a configured remote."
+    echo
+    __log_msg "Please use"
+    echo
+    __log_msg "  git branch --set-upstream-to=[remote_name]/$branch_name"
+    echo
+    __log_msg "replacing [remote_name] with the name of your remote, i.e. - origin"
+    __log_msg "to set the remote tracking branch for git-sync to work"
+    exit 2
+fi
+
+# check if current branch is configured for sync
+if [[ "true" != "$(git config --get --bool branch.$branch_name.sync)" && "true" != "$sync_anyway" ]] ; then
+    echo
+    __log_msg "Please use"
+    echo
+    __log_msg "  git config --bool branch.$branch_name.sync true"
+    echo
+    __log_msg "to enlist branch $branch_name for synchronization."
+    __log_msg "Branch $branch_name has to have a same-named remote branch"
+    __log_msg "for git-sync to work."
+    echo
+    __log_msg "(If you don't know what this means, you should change that"
+    __log_msg "before relying on this script. You have been warned.)"
+    echo
+    exit 1
+fi
+
+# determine mode
+if [[ -z "$1" || "$1" == "sync" ]]; then
+    mode="sync"
+elif [[ "check" == "$1" ]]; then
+    mode="check"
+else
+    __log_msg "Mode $1 not recognized"
+    exit 100
+fi
+
+__log_msg "Mode $mode"
+
+__log_msg "Using $remote_name/$branch_name"
+
+# check for intentionally unhandled file states
+if [ ! -z "$(check_initial_file_state)" ] ; then
+    __log_msg "There are changed files you should probably handle manually."
+    git status
+    exit 1
+fi
+
+# if in check mode, this is all we need to know
+if [ $mode == "check" ] ; then
+    __log_msg "check OK; sync may start."
+    exit 0
+fi
+
+# check if we have to commit local changes, if yes, do so
+if [ ! -z "$(local_changes)" ]; then
+    autocommit_cmd=""
+    config_autocommit_cmd="$(git config --get branch.$branch_name.autocommitscript)"
+
+    # discern the three ways to auto-commit
+    if [ ! -z "$config_autocommit_cmd" ]; then
+	autocommit_cmd="$config_autocommit_cmd"
+    elif [[ "true" == "$(git config --get --bool branch.$branch_name.syncNewFiles)" || "true" == "$sync_new_files_anyway" ]]; then
+	autocommit_cmd=${ALL_AUTOCOMMIT_CMD}
+    else
+        autocommit_cmd=${DEFAULT_AUTOCOMMIT_CMD}
+    fi
+
+    commit_msg="$(git config --get branch.$branch_name.syncCommitMsg)"
+    if [ "" == "$commit_msg" ]; then
+      commit_msg=${DEFAULT_AUTOCOMMIT_MSG}
+    fi
+    autocommit_cmd=$(echo "$autocommit_cmd" | sed "s/%message/$commit_msg/")
+
+    __log_msg "Committing local changes using ${autocommit_cmd}"
+    eval $autocommit_cmd
+
+    # after autocommit, we should be clean
+    rstate="$(git_repo_state)"
+    if [[ ! -z "$rstate" ]]; then
+	__log_msg "Auto-commit left uncommitted changes. Please add or remove them as desired and retry."
+	exit 1
+    fi
+fi
+
+# fetch remote to get to the current sync state
+# TODO make fetching/pushing optional
+__log_msg "Fetching from $remote_name/$branch_name"
+git fetch $remote_name $branch_name
+if [ $? != 0 ] ; then
+    __log_msg "git fetch $remote_name returned non-zero. Likely a network problem; exiting."
+    exit 3
+fi
+
+case "$(sync_state)" in
+"noUpstream")
+	__log_msg "Strange state, you're on your own. Good luck."
+	exit 2
+	;;
+"equal")
+	exit_assuming_sync
+	;;
+"ahead")
+	__log_msg "Pushing changes..."
+	git push $remote_name $branch_name:$branch_name
+	if [ $? == 0 ]; then
+	    exit_assuming_sync
+	else
+	    __log_msg "git push returned non-zero. Likely a connection failure."
+	    exit 3
+	fi
+	;;
+"behind")
+	__log_msg "We are behind, fast-forwarding..."
+	git merge --ff --ff-only $remote_name/$branch_name
+	if [ $? == 0 ]; then
+	    exit_assuming_sync
+	else
+	    __log_msg "git merge --ff --ff-only returned non-zero ($?). Exiting."
+	    exit 2
+	fi
+	;;
+"diverged")
+	__log_msg "We have diverged. Trying to rebase..."
+	git rebase $remote_name/$branch_name
+	if [[ $? == 0 && -z "$(git_repo_state)" && "ahead" == "$(sync_state)" ]] ; then
+	    __log_msg "Rebasing went fine, pushing..."
+	    git push $remote_name $branch_name:$branch_name
+	    exit_assuming_sync
+	else
+	    __log_msg "Rebasing failed, likely there are conflicting changes. Resolve them and finish the rebase before repeating git-sync."
+	    exit 1
+	fi
+	# TODO: save master, if rebasing fails, make a branch of old master
+	;;
+esac
diff --git a/roles/dotfiles/tasks/main.yml b/roles/dotfiles/tasks/main.yml
index 825f643..41115d3 100644
--- a/roles/dotfiles/tasks/main.yml
+++ b/roles/dotfiles/tasks/main.yml
@@ -98,6 +98,8 @@
     - '{{ home }}/pictures/shots/'
     - '{{ home }}/.gnupg/'
     - '{{ home }}/.sway/'
+    - '{{ home }}/bin/'
+    - '{{ home }}/.local/share/systemd/user'
 
 - name: Link files
   file:
@@ -132,3 +134,27 @@
       dest: '{{ home }}/.config/kanshi/config'
     - src: '{{ files_dir }}/foot.ini'
       dest: '{{ home }}/.config/foot/foot.ini'
+    - src: '{{ files_dir }}/bin/git-sync'
+      dest: '{{ home }}/bin/git-sync'
+
+- name: Create note sync service
+  template:
+    src: 'templates/systemd/note-sync/note-sync.service.j2'
+    dest: '{{ home }}/.local/share/systemd/user/note-sync.service'
+
+- name: Create note sync timer
+  template:
+    src: 'templates/systemd/note-sync/note-sync.timer.j2'
+    dest: '{{ home }}/.local/share/systemd/user/note-sync.timer'
+
+- name: Reload systemd
+  systemd:
+    scope: user
+    daemon_reload: true
+
+- name: Enable note sync timer
+  systemd:
+    name: note-sync.timer
+    scope: user
+    state: started
+    enabled: true
diff --git a/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.service.j2 b/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.service.j2
new file mode 100644
index 0000000..e48a06e
--- /dev/null
+++ b/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.service.j2
@@ -0,0 +1,8 @@
+[Unit]
+Description=Sync notes with git-sync
+
+[Service]
+Type=oneshot
+ExecStartPre=systemctl --user import-environment SSH_AUTH_SOCK
+WorkingDirectory={{ home }}/notes/
+ExecStart={{ home }}/bin/git-sync -ns
diff --git a/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.timer.j2 b/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.timer.j2
new file mode 100644
index 0000000..194ab0d
--- /dev/null
+++ b/roles/dotfiles/tasks/templates/systemd/note-sync/note-sync.timer.j2
@@ -0,0 +1,8 @@
+[Unit]
+Description=Note sync timer
+
+[Timer]
+OnCalendar=hourly
+
+[Install]
+WantedBy=timers.target