Add auto install feature for pre-commit plugin

plugins/pre-commit/pre-commit.plugin.zsh

@@ -6,3 +6,74 @@ alias prcau='pre-commit autoupdate'
 alias prcr='pre-commit run'
 alias prcra='pre-commit run --all-files'
 alias prcrf='pre-commit run --files'
+
+# Auto install
+
+## Settings
+
+# Filename of the pre-commit file to look for
+: ${ZSH_PRE_COMMIT_CONFIG_FILE:=.pre-commit-config.yaml}
+
+# Path to the file containing installed paths
+: ${ZSH_PRE_COMMIT_INSTALLED_LIST:="${ZSH_CACHE_DIR:-$ZSH/cache}/pre-commit-installed.list"}
+
+# Default setting for auto install to prompt
+: ${ZSH_PRE_COMMIT_AUTO_INSTALL:="prompt"}
+
+## Functions
+
+autoload -U add-zsh-hook
+if [[ "$ZSH_PRE_COMMIT_AUTO_INSTALL" == "off" ]]; then
+  add-zsh-hook -d chpwd auto_install_pre_commit
+  return
+fi
+
+auto_install_pre_commit() {
+  if [[ ! -f "$ZSH_PRE_COMMIT_CONFIG_FILE" ]]; then
+    return
+  fi
+
+  local dirpath="${PWD:A}"
+
+  # early return if already installed
+  if command grep -Fx -q "$dirpath" "$ZSH_PRE_COMMIT_INSTALLED_LIST" &>/dev/null; then
+    return
+  fi
+
+  if [[ "$ZSH_PRE_COMMIT_AUTO_INSTALL" == "prompt" ]]; then
+    local confirmation
+
+    touch "$ZSH_PRE_COMMIT_INSTALLED_LIST"
+
+    # get cursor column and print new line before prompt if not at line beginning
+    local column
+    echo -ne "\e[6n" > /dev/tty
+    read -t 1 -s -d R column < /dev/tty
+    column="${column##*\[*;}"
+    [[ $column -eq 1 ]] || echo
+
+    # print same-line prompt and output newline character if necessary
+    echo -n "pre-commit: found '$ZSH_PRE_COMMIT_CONFIG_FILE' file. Install hooks? ([Y]es/[A]sk again/[N]ever)"
+    read -k 1 confirmation
+    [[ "$confirmation" = $'\n' ]] || echo
+
+    # check input
+    case "$confirmation" in
+      [yY]) ;; # yes
+      [aA]) return ;; # ask again
+      [nN]) echo "$dirpath" >> "$ZSH_PRE_COMMIT_INSTALLED_LIST"; return ;; # never ask again
+      *) return ;; # interpret anything else as ask again
+    esac
+  fi
+
+  # check if pre-commit is installed
+  if ! type pre-commit > /dev/null; then
+    echo "You need to install pre-commit first. https://pre-commit.com/#install can help you out.";
+    return
+  fi
+
+  pre-commit install && echo "$dirpath" >> "$ZSH_PRE_COMMIT_INSTALLED_LIST"
+}
+
+add-zsh-hook chpwd auto_install_pre_commit
+auto_install_pre_commit