#!/bin/sh
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# This file is part of dobuild.
# Copyright (c) 2019 Contributors as noted in the AUTHORS file.
#
# SPDX-License-Identifier: MPL-2.0

set -e

# FIXME: don't depend on cmake internals
discover_cmake_includes() {
  if [ $# -gt 0 ]; then
    sed -n -e 's/.*_INCLUDE_DIRS:INTERNAL=\(.*\)$/\1/p' "$@";
  fi
}

discover_system_includes() {
  case "$BUILDSYSTEM" in
    cmake-?*)
      discover_cmake_includes "$@"
      ;;
    *)
      ;;
  esac
}

# FIXME: handle different compilers and language standards
discover_cc_includes() {
  {
    echo | "$CXX" -xc++ -E -Wp,-v - 2>&1
    echo | "$CC" -xc -E -Wp,-v - 2>&1
  } \
  | sed -n -e 's/\s\+\(\/.*$\).*/\1/p'
}

discover_includes() {
  {
    discover_cc_includes;
    discover_system_includes "$@"
  } \
  | sed 's/;/\n/g' |  sed '/^$/d' | sort -u 2>/dev/null \
  | while IFS= read -r file; do
    if [ -e "$file" ]; then
      canonicalize "$file"
    fi
  done
}

detect_toolchain() {
  case "$BUILDSYSTEM" in
    cmake-?*)
      cmake -LA -N "$(dirname "$1")" > "$CACHED_VALUES_TMPFILE"
      CXX="$(sed -n -e 's/CMAKE_CXX_COMPILER:FILEPATH=\(.*\)$/\1/p' -e 's/CMAKE_CXX_COMPILER:STRING=\(.*\)$/\1/p' "$CACHED_VALUES_TMPFILE")"
      CC="$(sed -n -e 's/CMAKE_C_COMPILER:FILEPATH=\(.*\)$/\1/p' -e 's/CMAKE_C_COMPILER:STRING=\(.*\)$/\1/p' "$CACHED_VALUES_TMPFILE")"
      ;;
    *)
      ;;
  esac
}

parse_make_targets() {
  parse_make_targets.sh -C "$WORKINGDIR"
}

parse_ninja_targets() {
  "$NINJA" -C "$WORKINGDIR" -t targets all | sed -n -e 's/\([^:]*\):.*/\1/p' | sort 2>/dev/null
}

discover_targets() {
  case "$BUILDSYSTEM" in
    cmake-make|make)
      parse_make_targets
      ;;
    cmake-ninja|ninja)
      parse_ninja_targets
      ;;
    *)
      ;;
  esac
}

prefix_dir() {
  while IFS= read -r dir; do
    printf '%s%s\n' "$1" "$dir"
  done
}

sed_keyword() {
  printf '%s\n' "$@" | sed -e 's/[]\/$*.^[]/\\&/g'
}

sed_replacement() {
  printf '%s\n' "$@" | sed -e 's/[\/&]/\\&/g'
}

format_json() {
  i=0
  printf '[\n'
  while IFS= read -r line; do
    if [ "$i" -gt 0 ]; then
      printf ',\n'
    fi
    printf '"%s"' "$line"
    i="$((i+1))"
  done
  printf '\n]\n'
}

physical_pwd() {
  pwd -P 2>/dev/null || pwd
}

try_canonicalize() {
  readlink -f "$@" 2>/dev/null || realpath "$@"
}

canonicalize() {
  if ! try_canonicalize "$1" 2>/dev/null; then
    echo "$(cd "$(dirname "$1")" && physical_pwd)/$(basename "$1")"
  fi
}

scriptdir() {
  dirname "$(canonicalize "${BASH_SOURCE:-$1}")"
}

cleanup() {
  EXITCODE="${EXITCODE:-$?}"
  rm -f "$INCLUDE_DIRS_TMPFILE" "$CACHED_VALUES_TMPFILE"
  return "$EXITCODE" 
}

trap cleanup TERM INT EXIT

export LANG=C
export LC_ALL=C

DOBUILDDIR="${DOBUILDDIR:-"$(dirname "$(scriptdir "$0")")"}"
NINJA="${NINJA:-ninja}"
PATH="$DOBUILDDIR/bin:$PATH"

set -- "$@" --

CXX=
CC=
BUILDSYSTEM=
WORKINGDIR="$PWD"
PROJECTDIR=
INCLUDE_PREFIX="$WORKINGDIR"
COMPILE_COMMANDS_JSON_FILE=

while :; do
  case $1 in
    -C|--directory)
      if [ "$2" != '--' ]; then
        WORKINGDIR="$2"
        shift
      else
        printf 'error: "%s" requires a non-empty option argument.\n' "$1" >&2
        exit 3
      fi
      ;;
    --directory=)
      printf 'error: "%s" requires a non-empty option argument.\n' "$1" >&2
      exit 3
      ;;
    --directory=?*)
      WORKINGDIR="${1#*=}"
      ;;
    --project-root)
      if [ "$2" != '--' ]; then
        PROJECTDIR="$2"
        shift
      else
        PROJECTDIR=
      fi
      ;;
    --project-root=)
      PROJECTDIR=
      ;;
    --project-root=?*)
      PROJECTDIR="${1#*=}"
      ;;
    --build-system)
      if [ "$2" != '--' ]; then
        BUILDSYSTEM="$2"
        shift
      else
        BUILDSYSTEM=
      fi
      ;;
    --build-system=)
      BUILDSYSTEM=
      ;;
    --build-system=?*)
      BUILDSYSTEM="${1#*=}"
      ;;
    -p|--include-prefix)
      if [ "$2" != '--' ]; then
        INCLUDE_PREFIX="$2"
        shift
      else
        INCLUDE_PREFIX=
      fi
      ;;
    --include-prefix=)
      INCLUDE_PREFIX=
      ;;
    --include-prefix=?*)
      INCLUDE_PREFIX="${1#*=}"
      ;;
    compile_commands.json|?*/compile_commands.json)
      COMPILE_COMMANDS_JSON_FILE="$1"
      ;;
    --help)
      {
        printf 'Usage: %s [option...] [file...]\n' "$(basename "$0")"
        printf 'Options:\n'
        printf '\t-C|--directory\t\tWorking directory\n'
        printf '\t--build-system\t\tBuildsystem kind e.g. cmake-make,cmake-ninja\n'
        printf '\t--project-root\t\tProject root directory\n'
        printf '\t-p|--include-prefix\tInclude prefix appended to all discovered include dirs\n'
        printf 'Files:\n'
        printf '\tBuildsystem specific configurations files e.g. CMakeCache.txt\n'
      } >&2
      exit 0
      ;;
    --)
      shift
      break
      ;;
    *)
      set -- "$@" "$1"
      ;;
  esac

  shift
done

OUTDIR="$WORKINGDIR/DoBuildFiles"
mkdir -p "$OUTDIR"

INCLUDE_PREFIX_REPLACEMENT="%OUTDIR%/$INCLUDE_PREFIX"

CACHED_VALUES_TMPFILE="$(mktemp -p "$OUTDIR" cached_values_XXXXXXXXXX.txt)"
INCLUDE_DIRS_TMPFILE="$(mktemp -p "$OUTDIR" include_dirs_XXXXXXXXXX.txt)"
INCLUDE_DIRS_TMPL_FILE="$OUTDIR/include_dirs.json.template"
TARGETS_JSON_FILE="$OUTDIR/targets.json"
TARGETS_TXT_FILE="$OUTDIR/targets.txt"
COMPILE_COMMANDS_TMPL_FILE="$OUTDIR/compile_commands.json.template"
C_BUILTIN_FILE="$OUTDIR/builtins.h"
CXX_BUILTIN_FILE="$OUTDIR/builtins.hpp"

detect_toolchain "$@"

discover_targets "$@" | tee "$TARGETS_TXT_FILE" | format_json > "$TARGETS_JSON_FILE"
discover_includes "$@" | tee "$INCLUDE_DIRS_TMPFILE" | prefix_dir "$INCLUDE_PREFIX_REPLACEMENT" | format_json > "$INCLUDE_DIRS_TMPL_FILE"

# FIXME: handle different compilers and language standards
"$CC" -xc -dM -E - < /dev/null > "$C_BUILTIN_FILE"
"$CXX" -xc++ -dM -E - < /dev/null > "$CXX_BUILTIN_FILE"

if [ -n "$COMPILE_COMMANDS_JSON_FILE" ]; then
  set -- 
  while IFS= read -r line; do
    set -- "$@" -e "s/$(sed_keyword "${line}")/$(sed_replacement "${INCLUDE_PREFIX_REPLACEMENT}${line}")/g"
  done < "$INCLUDE_DIRS_TMPFILE"
  set -- "$@" -e "s/$(sed_keyword "$WORKINGDIR")/$(sed_replacement "%OUTDIR%")/g"
  if [ -n "$PROJECTDIR" ]; then
    set -- "$@" -e "s/$(sed_keyword "$PROJECTDIR")/$(sed_replacement "%PROJECTDIR%")/g"
  fi
  set -- "$@" "$COMPILE_COMMANDS_JSON_FILE"
  sed "$@" > "$COMPILE_COMMANDS_TMPL_FILE"
fi

set --

if [ -n "$INCLUDE_PREFIX" ]; then
  while IFS= read -r file; do
    set -- "$@" "$file"
  done < "$INCLUDE_DIRS_TMPFILE"
fi

cleanup

exec tar cf - -C / "$@"