#!/usr/bin/env bash
# used in Travis CI and AppVeyor scripts

# Copyright (c) 2018-2020 Status Research & Development GmbH. Licensed under
# either of:
# - Apache License, version 2.0
# - MIT license
# at your option. This file may not be copied, modified, or distributed except
# according to those terms.

set -e

NIM_COMMIT_HASH="" # full hash for NIM_COMMIT, retrieved in "nim_needs_rebuilding()"

NIM_DIR=nim
CSOURCES_DIR=nim-csources
NIMBLE_DIR=nimble

cd "$(dirname "${BASH_SOURCE}")"
cd ..

## env vars
# verbosity level
[ -z "${V}" ] && V=0
[ -z "${CC}" ] && CC="gcc"
# to build csources in parallel, set MAKE="make -jN"
[ -z "${MAKE}" ] && MAKE="make"
# for 32-bit binaries on a 64-bit host
UCPU=""
[ "${ARCH_OVERRIDE}" = "x86"       ] && UCPU="ucpu=i686"
[ -z "${NIM_BUILD_MSG}"            ] && NIM_BUILD_MSG="Building the Nim compiler (${NIM_COMMIT})"
[ -z "${CSOURCES_COMMIT}"          ] && CSOURCES_COMMIT=a8a5241f9475099c823cfe1a5e0ca4022ac201ff
[ -z "${NIM_REPO}"                 ] && NIM_REPO="https://github.com/status-im/Nim.git"
[ -z "${NIMBLE_REPO}"              ] && NIMBLE_REPO="https://github.com/nim-lang/nimble.git"
[ -z "${NIM_COMMIT}"               ] && { echo "Please specify NIM_COMMIT"; exit 1; }
[ -z "${NIMBLE_COMMIT}"            ] && { echo "Please specify NIMBLE_COMMIT"; exit 1; }

# Windows detection
if uname | grep -qiE "mingw|msys"; then
  ON_WINDOWS=1
  EXE_SUFFIX=".exe"
  # otherwise it fails in AppVeyor due to https://github.com/git-for-windows/git/issues/2495
  GIT_TIMESTAMP_ARG="--date=unix" # available since Git 2.9.4
else
  ON_WINDOWS=0
  EXE_SUFFIX=""
  GIT_TIMESTAMP_ARG="--date=format-local:%s" # available since Git 2.7.0
fi

NIM_BINARY="${NIM_DIR}/bin/nim${EXE_SUFFIX}"

nim_needs_rebuilding() {
  REBUILD=0
  NO_REBUILD=1

  if [ ! -e "${NIM_DIR}" ]; then
    # Shallow clone, optimised for the default NIM_COMMIT value.
    git clone -q --depth=1 "${NIM_REPO}" "${NIM_DIR}"
  fi

  pushd "${NIM_DIR}" >/dev/null
    # support old Git versions, like the one from Ubuntu-18.04
    git restore . 2>/dev/null || git reset --hard
    if ! git checkout -q "${NIM_COMMIT}" 2>/dev/null; then
      # Pay the price for a non-default NIM_COMMIT here, by fetching everything.
      # (This includes upstream branches and tags that might be missing from our fork.)
      git remote add upstream https://github.com/nim-lang/Nim
      git fetch --all
      git checkout -q "${NIM_COMMIT}" 2>/dev/null
    fi

    # In case the local branch diverged and a fast-forward merge is not possible.
    git fetch || true
    git reset -q --hard origin/${NIM_COMMIT} 2> /dev/null || true
    # In case NIM_COMMIT is a local branch that's behind the remote one it's tracking.
    git pull -q 2>/dev/null || true
    git checkout -q ${NIM_COMMIT} 2>/dev/null
    # We can't use "rev-parse" here, because it would return the tag object's
    # hash instead of the commit hash, when NIM_COMMIT is a tag.
    NIM_COMMIT_HASH="$(git rev-list -n 1 ${NIM_COMMIT})"
  popd >/dev/null

  # compare the last built commit to the one requested
  if [ -e "${NIM_DIR}/bin/nim_commit_${NIM_COMMIT_HASH}" ]; then
    # we built the requested commit in the past, so we simply reuse it
    rm -f "${NIM_DIR}/bin/nim${EXE_SUFFIX}"
    ln -s "nim_commit_${NIM_COMMIT_HASH}" "${NIM_DIR}/bin/nim${EXE_SUFFIX}"
    return ${NO_REBUILD}
  else
    return ${REBUILD}
  fi
}

build_nim() {
  echo "$NIM_BUILD_MSG"
  [ $V -eq 0 ] && exec >/dev/null 2>&1

  pushd "${NIM_DIR}"
   # Git repos for csources and Nimble
    if [ ! -d "${CSOURCES_DIR}" ]; then
      mkdir -p "${CSOURCES_DIR}"
      pushd "${CSOURCES_DIR}"
        git clone https://github.com/nim-lang/csources_v1.git .
        git checkout $CSOURCES_COMMIT
      popd
    fi
    if [ ! "${CSOURCES_DIR}" = "csources" ]; then
      rm -rf csources
      ln -s "${CSOURCES_DIR}" csources
    fi
    if [ ! -d "${NIMBLE_DIR}" ]; then
      mkdir -p "${NIMBLE_DIR}"
      pushd "${NIMBLE_DIR}"
        git clone "${NIMBLE_REPO}" .
        git checkout "${NIMBLE_COMMIT}"
        # we have to delete .git or koch.nim will checkout a branch tip, overriding our target commit
        # TODO
        # This is quite the hack and it breaks the output of `nimble --version`
        # which prints the Nim revision instead of the Nimble revision.
        rm -rf .git
      popd
    fi

    mkdir -p dist
    rm -rf dist/nimble
    ln -s ../"${NIMBLE_DIR}" dist/nimble

    # Clean up the new Nimble cache, because the csources build
    # won't recognize the validity of the packages there:
    rm -rf ~/.nimble/pkgs2

    # bootstrap the Nim compiler and build the tools
    rm -f bin/nim bin/nim_csources
    pushd csources
      if [ ${ON_WINDOWS} -eq 0 ]; then
        "${MAKE}" ${UCPU} clean
        "${MAKE}" ${UCPU} LD=${CC}
      else
        "${MAKE}" myos=windows ${UCPU} clean
        "${MAKE}" myos=windows ${UCPU} CC=gcc LD=gcc
      fi
    popd

    if [ -e csources/bin ]; then
      rm -f bin/nim bin/nim_csources
      cp -a csources/bin/nim bin/nim
      cp -a csources/bin/nim bin/nim_csources
      rm -rf csources/bin
    else
      cp -a bin/nim bin/nim_csources
    fi

    sed \
      -e 's/koch$/--warnings:off --hints:off koch/' \
      -e 's/koch boot/koch boot --warnings:off --hints:off/' \
      -e '/nimBuildCsourcesIfNeeded/d' \
      build_all.sh > build_all_custom.sh
    sh build_all_custom.sh
    rm -f build_all_custom.sh
    # Nimble needs a CA cert
    rm -f bin/cacertmony.pem
    curl -LsS -o bin/cacert.pem https://curl.se/ca/cacert.pem || echo "Warning: 'curl' failed to download a CA cert needed by Nimble. Ignoring it."

    # create the symlink
    mv bin/nim "bin/nim_commit_${NIM_COMMIT_HASH}"
    ln -s "nim_commit_${NIM_COMMIT_HASH}" "bin/nim${EXE_SUFFIX}"
  popd

  [ $V -eq 0 ] && exec >$(tty) 2>&1
}

if nim_needs_rebuilding; then
  build_nim
fi

set +e