#!/usr/bin/env bash

# This script manages the environment needed by the helper scripts
# It needs to have one environment variable set in order to do its job:
# LLVM_ROOT - the directory under which the llvm sources and build directories
# will live

# This script is meant to be sourced, so we don't want things to exit on error,
# because that would kill the whole shell. Instead, we trap and return from the
# script (which leaves the shell running, so people can see what went wrong).
clean_exit="trap '' ERR; return"

trap "$clean_exit" ERR

. llvm-common

# Check that we have actually been sourced
if [ -z "$PS1" ]; then
  echo "This script must be sourced. You might want to create an alias llvm-env=\". llvm-env\""
  exit 1
fi

list_worktrees() {
  current_worktree=$1

  # FIXME:
  # Ideally we would just use git for this (I think git 2.7-ish should suffice),
  # but I'm currently stuck with git 2.5 on my Ubuntu and it seems to me the
  # rest of the team is on older gits too. Until we all move to a smarter git,
  # we're going to use the simplest possible implementation that can give us
  # what we want (the proper way to do this ofc would be to inspect
  # $GITDIR/worktrees/). This implementation has the disadvantage that it may
  # give false positives or false negatives if you do naughty things with your
  # $LLVM_ROOT.
  pushdq $LLVM_ROOT

  for dir in *; do
    if [ -d "$dir" -a -f "$dir/llvm/.git" ]; then
      pushdq $dir/llvm
      branch=`get_branch`
      popdq

      if [ "$current_worktree" = "$LLVM_ROOT/$dir/llvm" ]; then
        echo "[ $dir ($branch) ]"
      else
        echo "$dir ($branch)"
      fi
    fi
  done

  popdq

}

if [ "$1" = "" ]; then
  if [ -z "$LLVM_SRC" ]; then
    list_worktrees
    echo "You haven't set up an env (LLVM_SRC is empty)"
    eval $clean_exit
  fi

  worktree=`basename $(readlink -m $LLVM_SRC/../)`

  list_worktrees $LLVM_SRC

  eval $clean_exit
elif [ "$1" = "-h" ]; then
  echo "Usage: $0 <branch> [-cleanup] [-d]"
  echo "  <branch> : the name of the branch you want to set the env for;"
  echo "             it will be created if it does not already exist."
  echo "  -cleanup : will clean up the environment corresponding to <branch>;"
  echo "             this includes the worktrees for all the subprojects, as"
  echo "             well as any directories in that environment (especially the"
  echo "             build dirs!)"
  echo "             it will not clean up any branches (you should use"
  echo "             llvm-branch for that)"
  echo "  -d : build the debug version."
  echo "  -s : build the self-hosted version (CC is set to <branch>/build)."
  eval $clean_exit
fi

branch=$1
shift

if [[ $branch = -* ]]; then
  echo "Invalid branch name $branch"
  eval $clean_exit
fi

if [ "$branch" = "master" ]; then
  echo "Building master directly is not supported."
  echo "You can instead run 'llvm-env TrackMaster'"
  echo "to create an environment that tracks master."
  eval $clean_exit
fi

clean=false
if [ "$1" = "-cleanup" ]; then
  clean=true
  shift
fi

debug_build=false
selfhost_build=false
OPTIND=0
while getopts "ds" opt; do
  if [ "$opt" = "d" ]; then
    debug_build=true
  elif [ "$opt" = "s" ]; then
    selfhost_build=true
  else
    eval $clean_exit
  fi
  shift
done

if [ "$1" != "" ]; then
  echo "Too many args?"
  eval $clean_exit
fi

llvm_dir=$LLVM_ROOT/repos/llvm
llvm_worktree_dir=$LLVM_ROOT/$branch/llvm

llvm_build_dir=$LLVM_ROOT/$branch/build
if $debug_build; then
  llvm_build_dir=$LLVM_ROOT/$branch/debug
elif $selfhost_build; then
  if [ ! -d "$llvm_build_dir" ] || \
     [ ! -x "$llvm_build_dir/bin/clang" ] || \
     [ ! -x "$llvm_build_dir/bin/clang++" ]; then
    echo "Stage 1 build dir not found at: $llvm_build_dir"
    echo "Build stage 1 first, then the self-hosted"
    eval $clean_exit
  fi
  llvm_stage1_dir=$llvm_build_dir
  llvm_build_dir=$LLVM_ROOT/$branch/selfhost
fi

llvm_install_dir=$LLVM_ROOT/$branch/install

if [ "$clean" = true ]; then
  .llvm-env-remove $llvm_dir $llvm_worktree_dir
else
  .llvm-env-add $branch $llvm_dir $llvm_worktree_dir
fi

# Changes to the environment should be confined to the end of the script, to
# make sure we don't change half the environment and then fail out

if [ "$clean" = true ]; then
  # Clean up the environment to make sure the other scripts error out
  # accordingly instead of trying anything stupid
  export LLVM_SRC=
  export LLVM_BLD=
  export LLVM_DEBUG=
  if [ ! -z "$LLVM_OLD_PATH" ]; then
    export PATH=$LLVM_OLD_PATH
  fi
  eval $clean_exit
fi

export LLVM_SRC=$llvm_worktree_dir
export LLVM_BLD=$llvm_build_dir
export LLVM_INSTALL=$llvm_install_dir
# For llvm-build to know
export LLVM_DEBUG=$debug_build
export LLVM_SELFHOST=$selfhost_build

# Self-hosted builds need to use the previously built clang, maybe LLD.
if $selfhost_build; then
  # Clang will automatically pick LLD if available on the same dir
  LLVM_CMAKE_FLAGS="-DCMAKE_C_COMPILER=$llvm_stage1_dir/bin/clang \
                    -DCMAKE_CXX_COMPILER=$llvm_stage1_dir/bin/clang++"
  export LLVM_CMAKE_FLAGS
fi

# Make it possible to undo changes to the PATH: we export an LLVM_OLD_PATH, and
# instead of appending the binary dir to $PATH, we append to $LLVM_OLD_PATH (if
# it exists)
# This is intended to support scenarios where you want to switch between a
# release and debug build of the same branch in the same shell, without growing
# a huge PATH
path_to_add_to=$PATH
if [ ! -z "$LLVM_OLD_PATH" ]; then
  path_to_add_to=$LLVM_OLD_PATH
fi

export LLVM_OLD_PATH=$path_to_add_to
export PATH=$llvm_build_dir/bin:$path_to_add_to

eval $clean_exit