Replace build-dir.py with zcurses build-dir

Update the build-dir shell function to usage zcurses instead of the
Python pick package to interactively select build directories, this
results in a more responsive user experience. Add argument parsing to
handle various use cases. Add prompt when the build command for the
selected build directory could not be detected, allowing the user to
specify the desired build command.

```
usage: build-dir [-h] [--build] [<directory>]

Find and select the current build directory interactively.

positional arguments:
  <directory> the build directory to select

optional arguments:
  -h, --help  show this help message and exit
  --build     invoke a build after selection
```

.conduit.yaml

@@ -16,6 +16,8 @@
     - {src: zshrc, dst: ~/.zshrc}
     - src: prompt_fresh_setup
       dst: ~/.local/share/zsh/site-functions/prompt_fresh_setup
+    - src: build/_build-dir
+      dst: ~/.local/share/zsh/site-functions/_build-dir
     - src: sandbox/_sandbox
       dst: ~/.local/share/zsh/site-functions/_sandbox
     - src: layout/_layout
@@ -26,6 +28,4 @@
     - https://github.com/zsh-users/zsh-autosuggestions.git
     - https://github.com/zsh-users/zsh-history-substring-search.git
     - https://github.com/zdharma/fast-syntax-highlighting.git
-- pip:
-    - pick
 - message: zsh will be the default prompt after next login

build/_build-dir

@@ -0,0 +1,6 @@
+#compdef build-dir
+
+_arguments \
+  '(-h --help)'{-h,--help}'[]' \
+  '--build[invoke a build after selection]' \
+  '1:directory:_files'

build/build.plugin.zsh

@@ -17,46 +17,140 @@ elif [ `uname` = Darwin ]; then
     alias debug='lldb --'
 fi
 
-# Store the path to `build-dir.py`, using `${0:a:h}` does not work in a
-# function because it will result in `pwd` not this scripts directory.
-_build_dir_py=${0:a:h}/build-dir.py
-
 # Interactively choose a `~build` directory for `build` to build.
-# TODO: Support arguments:
-# * [ ] [-h,--help] - show this help message and exit
-# * [x] [--build] - execute the build commend
-# * [ ] <dir> - start in another directory, not `pwd`
 build-dir() {
-  # Get a unique filename to store the chosen build directory in.
-  [ `uname` = Darwin ] && local file=`mktemp` || local file=`tempfile`
-  # Prompt user to choose a build directory.
-  python $_build_dir_py $file;
-  local error=$?
-  # If the file exists, read the build directory from it, then delete it.
-  [ -f $file ] && local build_dir=$PWD/`cat $file`; rm $file
-  # If choosing a build directory failed, return that error.
-  [[ "$error" = "0" ]] || return $error
-  # If `build.ninja` exists in alias `ninja`, return.
-  [ -f $build_dir/build.ninja ] && \
-    local build="ninja -C $build_dir"
-  # If `Makefile` exists in alias `make`, return.
-  if [ -f $build_dir/Makefile ]; then
-    [ `uname` = Darwin ] && \
-      local cpu_count=`sysctl -n hw.ncpu` ||
-      local cpu_count=`grep -c '^processor' /proc/cpuinfo`
-    local build="make -j $cpu_count -C $build_dir"
+  local usage='usage: build-dir [-h] [--build] [<directory>]'
+  local -a help do_build
+  zparseopts -D h=help -help=help -build=do_build
+  if [[ -n $help ]]; then
+    cat << EOF
+$usage
+
+Find and select the current build directory interactively.
+
+positional arguments:
+  <directory> the build directory to select
+
+optional arguments:
+  -h, --help  show this help message and exit
+  --build     invoke a build after selection
+EOF
+    exit
   fi
-  # If the build variable is not defined the command could not be determined.
-  if [ -z $build ]; then
-    # TODO: Prompt user to choose a build command?
-    echo "could not determine build command"
-    return 1
+  error() { echo "\e[31merror:\e[0m $1"; exit 1 }
+  local build_dir
+  if [[ ${#*} -gt 1 ]]; then
+    echo $usage
+    error "unexpected position arguments: ${*[2,${#*}]}"
+  elif [[ ${#*} -eq 1 ]]; then
+    build_dir=${*[1]}
+    [[ ! -d $build_dir ]] && \
+      error "directory not found: $build_dir"
+  fi
+
+  # If <directory> was not set begin selection
+  if [[ -z $build_dir ]]; then
+    # Find build directories
+    local -a build_dirs
+    for entry in `ls -A`; do
+      [ -d $entry ] && [[ $entry =~ build* ]] && \
+        build_dirs+=$entry
+    done
+
+    # Interactively select a build directory if more than 1 found
+    integer index=0
+    if [[ ${#build_dirs} -eq 0 ]]; then
+      error "no build directories found"
+    elif [[ ${#build_dirs} -gt 1 ]]; then
+      zmodload zsh/curses && {
+        # Get the size of the terminal
+        local size=`stty size`
+        integer height=${size% *}
+        integer width=${size#* }
+
+        # Create the window and hide the cursor
+        zcurses init
+        zcurses addwin build-dir $height $width 0 0
+
+        # Hide the cursor for zcurses, trap SIGINT to ensure cleanup in
+        # always-list occurs below
+        tput civis; trap 'exit 130' INT
+
+        # Enter display loop
+        local key keypad
+        while (( 1 )); do
+          zcurses clear build-dir
+
+          # Add the prompt text
+          zcurses move build-dir 1 1
+          zcurses string build-dir 'Select a build directory:'
+
+          # Add the selections text
+          for (( i = 0; i < ${#build_dirs}; i++ )); do
+            integer line=$i+3
+            zcurses move build-dir $line 1
+            [[ $index -eq $i ]] &&
+              zcurses string build-dir "* " ||
+              zcurses string build-dir "  "
+            zcurses string build-dir ${build_dirs[$i+1]}
+          done
+
+          # Display the text the and wait for input
+          zcurses refresh build-dir
+          zcurses input build-dir key keypad
+
+          # Handle user input
+          case $key in
+            (UP|k|$'\C-P')
+              [[ $index -gt 0 ]] && index=$index-1 ;;
+            (DOWN|j|$'\C-N')
+              [[ $index -lt ${#build_dirs}-1 ]] && index=$index+1 ;;
+            (ENTER|$'\n')
+              break ;;
+          esac
+        done
+      } always {
+        # Restore the cursor and cleanup zcurses
+        tput cvvis; tput cnorm
+        zcurses delwin build-dir
+        zcurses end
+      }
+    fi
+  fi
+
+  # On success setup the build directory for use
+  if [[ $? -eq 0 ]]; then
+    # Set the build directory from selection if empty
+    [[ -z $build_dir ]] && \
+      build_dir=${build_dirs[$index+1]}
+
+    # If `build.ninja` exists in alias `ninja`, return.
+    local build
+    [ -f $build_dir/build.ninja ] && \
+      build="ninja -C $build_dir"
+
+    # If `Makefile` exists in alias `make`, return.
+    if [ -f $build_dir/Makefile ]; then
+      [ `uname` = Darwin ] && \
+        local cpu_count=`sysctl -n hw.ncpu` ||
+        local cpu_count=`grep -c '^processor' /proc/cpuinfo`
+      build="make -j $cpu_count -C $build_dir"
+    fi
+
+    # If the build variable is not defined the command could not be determined
+    if [ -z $build ]; then
+      echo "\e[33mwarning:\e[0m build command detection failed: $build_dir"
+      # Prompt user to enter a build command
+      vared -p 'enter comand: ' build
+    fi
+
+    # Redefine the `build` alias and update the `~build` hash directory
+    alias build="$build"
+    hash -d build=$build_dir
+
+    # If `--build` is specified then evaluate the command.
+    [[ -n $do_build ]] && eval build
   fi
-  # Redefine the `build` alias and update the `~build` hash directory.
-  alias build="$build"
-  hash -d build=$build_dir
-  # If `--build` is specified then evaluate the command.
-  [[ "$1" = "--build" ]] && eval $build || true
 }
 
 # Build then run a target residing in `~build/bin`.