#!/usr/bin/env bash

set -e

ARG0=$0
print_help() {
    NAME=$(basename "$ARG0")
    cat <<EOF
Usage: $NAME COMMAND [TARGET] [TOOLCHAIN] [ARGS...]
  Supported TARGETs: aarch64, x86_64, lagom. Defaults to SERENITY_ARCH, or x86_64 if not set.
  Supported TOOLCHAINs: GNU, Clang. Defaults to SERENITY_TOOLCHAIN, or GNU if not set.
  Supported COMMANDs:
    build:      Compiles the target binaries, [ARGS...] are passed through to ninja
    install:    Installs the target binary
    image:      Creates a disk image with the installed binaries
    run:        TARGET lagom: $NAME run lagom LAGOM_EXECUTABLE [ARGS...]
                    Runs the Lagom-built LAGOM_EXECUTABLE on the build host, e.g.
                    'shell' or 'js', [ARGS...] are passed through to the executable
                All other TARGETs: $NAME run [TARGET] [KERNEL_CMD_LINE]
                    Runs the built image in QEMU, and optionally passes the
                    KERNEL_CMD_LINE to the Kernel
    gdb:        Same as run, but also starts a gdb remote session.
                TARGET lagom: $NAME gdb lagom LAGOM_EXECUTABLE [-ex 'any gdb command']...
                    Passes through '-ex' commands to gdb
                All other TARGETs: $NAME gdb [TARGET] [KERNEL_CMD_LINE] [-ex 'any gdb command']...
                    If specified, passes the KERNEL_CMD_LINE to the Kernel
                    Passes through '-ex' commands to gdb
    test:       TARGET lagom: $NAME test lagom [TEST_NAME_PATTERN]
                    Runs the unit tests on the build host, or if TEST_NAME_PATTERN
                    is specified tests matching it.
                All other TARGETs: $NAME test [TARGET]
                    Runs the built image in QEMU in self-test mode, by passing
                    system_mode=self-test to the Kernel
    delete:     Removes the build environment for TARGET
    recreate:   Deletes and re-creates the build environment for TARGET
    rebuild:    Deletes and re-creates the build environment, and compiles for TARGET
    kaddr2line: $NAME kaddr2line TARGET ADDRESS
                    Resolves the ADDRESS in the Kernel/Kernel binary to a file:line
    addr2line:  $NAME addr2line TARGET BINARY_FILE ADDRESS
                    Resolves the ADDRESS in BINARY_FILE to a file:line. It will
                    attempt to find the BINARY_FILE in the appropriate build directory
    rebuild-toolchain: Deletes and re-builds the TARGET's toolchain
    rebuild-world:     Deletes and re-builds the toolchain and build environment for TARGET.
    copy-src:   Same as image, but also copies the project's source tree to ~/Source/serenity
                in the built disk image.


  Examples:
    $NAME run x86_64 GNU smp=on
        Runs the image in QEMU passing "smp=on" to the kernel command line
    $NAME run x86_64 GNU 'init=/bin/UserspaceEmulator init_args=/bin/SystemServer'
        Runs the image in QEMU, and run the entire system through UserspaceEmulator (not fully supported yet)
    $NAME run
        Runs the image for the default TARGET x86_64 in QEMU
    $NAME run lagom js -A
        Runs the Lagom-built js(1) REPL
    $NAME test lagom
        Runs the unit tests on the build host
    $NAME kaddr2line x86_64 0x12345678
        Resolves the address 0x12345678 in the Kernel binary
    $NAME addr2line x86_64 WindowServer 0x12345678
        Resolves the address 0x12345678 in the WindowServer binary
    $NAME gdb x86_64 smp=on -ex 'hb *init'
        Runs the image for the TARGET x86_64 in qemu and attaches a gdb session
        setting a breakpoint at the init() function in the Kernel.
EOF
}

usage() {
    >&2 print_help
    exit 1
}

CMD=$1
[ -n "$CMD" ] || usage
shift
if [ "$CMD" = "help" ]; then
    print_help
    exit 0
fi

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# shellcheck source=/dev/null
. "${DIR}/shell_include.sh"

exit_if_running_as_root "Do not run serenity.sh as root, your Build directory will become root-owned"

if [ -n "$1" ]; then
    TARGET="$1"; shift
else
    TARGET="${SERENITY_ARCH:-"x86_64"}"
fi

CMAKE_ARGS=()
HOST_COMPILER=""

# Toolchain selection only applies to non-lagom targets.
if [ "$TARGET" != "lagom" ] && [ -n "$1" ]; then
    TOOLCHAIN_TYPE="$1"; shift
else
    TOOLCHAIN_TYPE="${SERENITY_TOOLCHAIN:-"GNU"}"
fi
if ! [[ "${TOOLCHAIN_TYPE}" =~ ^(GNU|Clang)$ ]]; then
    >&2 echo "ERROR: unknown toolchain '${TOOLCHAIN_TYPE}'."
    exit 1
fi
CMAKE_ARGS+=( "-DSERENITY_TOOLCHAIN=$TOOLCHAIN_TYPE" )

CMD_ARGS=( "$@" )

get_top_dir() {
    git rev-parse --show-toplevel
}

is_valid_target() {
    if [ "$TARGET" = "aarch64" ]; then
        CMAKE_ARGS+=("-DSERENITY_ARCH=aarch64")
        return 0
    fi
    if [ "$TARGET" = "x86_64" ]; then
        CMAKE_ARGS+=("-DSERENITY_ARCH=x86_64")
        return 0
    fi
    if [ "$TARGET" = "lagom" ]; then
        CMAKE_ARGS+=("-DBUILD_LAGOM=ON")
        if [ "${CMD_ARGS[0]}" = "ladybird" ]; then
            CMAKE_ARGS+=("-DENABLE_LAGOM_LADYBIRD=ON")
        fi
        return 0
    fi
    return 1
}

create_build_dir() {
    if [ "$TARGET" != "lagom" ]; then
        cmake -GNinja "${CMAKE_ARGS[@]}" -S "$SERENITY_SOURCE_DIR/Meta/CMake/Superbuild" -B "$SUPER_BUILD_DIR"
    else
        cmake -GNinja "${CMAKE_ARGS[@]}" -S "$SERENITY_SOURCE_DIR/Meta/Lagom" -B "$SUPER_BUILD_DIR"
    fi
}

is_supported_compiler() {
    local COMPILER="$1"
    if [ -z "$COMPILER" ]; then
        return 1
    fi

    local VERSION=""
    VERSION="$($COMPILER -dumpversion)" || return 1
    local MAJOR_VERSION=""
    MAJOR_VERSION="${VERSION%%.*}"
    if $COMPILER --version 2>&1 | grep "Apple clang" >/dev/null; then
        # Apple Clang version check
        BUILD_VERSION=$(echo | $COMPILER -dM -E - | grep __apple_build_version__ | cut -d ' ' -f3)
        # Xcode 14.3, based on upstream LLVM 15
        [ "$BUILD_VERSION" -ge 14030022 ] && return 0
    elif $COMPILER --version 2>&1 | grep "clang" >/dev/null; then
        # Clang version check
        [ "$MAJOR_VERSION" -ge 14 ] && return 0
    else
        # GCC version check
        [ "$MAJOR_VERSION" -ge 12 ] && return 0
    fi
    return 1
}

find_newest_compiler() {
    local BEST_VERSION=0
    local BEST_CANDIDATE=""
    for CANDIDATE in "$@"; do
        if ! command -v "$CANDIDATE" >/dev/null 2>&1; then
            continue
        fi
        if ! $CANDIDATE -dumpversion >/dev/null 2>&1; then
            continue
        fi
        local VERSION=""
        VERSION="$($CANDIDATE -dumpversion)"
        local MAJOR_VERSION="${VERSION%%.*}"
        if [ "$MAJOR_VERSION" -gt "$BEST_VERSION" ]; then
            BEST_VERSION=$MAJOR_VERSION
            BEST_CANDIDATE="$CANDIDATE"
        fi
    done
    HOST_COMPILER=$BEST_CANDIDATE
}

pick_host_compiler() {
    if is_supported_compiler "$CC" && is_supported_compiler "$CXX"; then
        return
    fi

    find_newest_compiler clang clang-14 clang-15 clang-16 /opt/homebrew/opt/llvm/bin/clang
    if is_supported_compiler "$HOST_COMPILER"; then
        export CC="${HOST_COMPILER}"
        export CXX="${HOST_COMPILER/clang/clang++}"
        return
    fi

    find_newest_compiler egcc gcc gcc-12 gcc-13 /usr/local/bin/gcc-{12,13} /opt/homebrew/bin/gcc-{12,13}
    if is_supported_compiler "$HOST_COMPILER"; then
        export CC="${HOST_COMPILER}"
        export CXX="${HOST_COMPILER/gcc/g++}"
        return
    fi

    if [ "$(uname -s)" = "Darwin" ]; then
        die "Please make sure that Xcode 14.3, Homebrew Clang 14, or higher is installed."
    else
        die "Please make sure that GCC version 12, Clang version 14, or higher is installed."
    fi
}

cmd_with_target() {
    is_valid_target || ( >&2 echo "Unknown target: $TARGET"; usage )

    pick_host_compiler
    CMAKE_ARGS+=("-DCMAKE_C_COMPILER=${CC}")
    CMAKE_ARGS+=("-DCMAKE_CXX_COMPILER=${CXX}")

    if [ ! -d "$SERENITY_SOURCE_DIR" ]; then
        SERENITY_SOURCE_DIR="$(get_top_dir)"
        export SERENITY_SOURCE_DIR
    fi
    local TARGET_TOOLCHAIN=""
    if [[ "$TOOLCHAIN_TYPE" != "GNU" && "$TARGET" != "lagom" ]]; then
        # Only append the toolchain if it's not GNU
        TARGET_TOOLCHAIN=$(echo "$TOOLCHAIN_TYPE" | tr "[:upper:]" "[:lower:]")
    fi
    BUILD_DIR="$SERENITY_SOURCE_DIR/Build/$TARGET$TARGET_TOOLCHAIN"
    if [ "$TARGET" != "lagom" ]; then
        export SERENITY_ARCH="$TARGET"
        export SERENITY_TOOLCHAIN="$TOOLCHAIN_TYPE"
        if [ "$TOOLCHAIN_TYPE" = "Clang" ]; then
            TOOLCHAIN_DIR="$SERENITY_SOURCE_DIR/Toolchain/Local/clang"
        else
            TOOLCHAIN_DIR="$SERENITY_SOURCE_DIR/Toolchain/Local/$TARGET_TOOLCHAIN/$TARGET"
        fi
        SUPER_BUILD_DIR="$SERENITY_SOURCE_DIR/Build/superbuild-$TARGET$TARGET_TOOLCHAIN"
    else
        SUPER_BUILD_DIR="$BUILD_DIR"
        CMAKE_ARGS+=("-DCMAKE_INSTALL_PREFIX=$SERENITY_SOURCE_DIR/Build/lagom-install")
        CMAKE_ARGS+=("-DSERENITY_CACHE_DIR=${SERENITY_SOURCE_DIR}/Build/caches")
    fi
    export PATH="$SERENITY_SOURCE_DIR/Toolchain/Local/cmake/bin":$PATH
}

ensure_target() {
    [ -f "$SUPER_BUILD_DIR/build.ninja" ] || create_build_dir
}

run_tests() {
    local TEST_NAME="$1"
    export CTEST_OUTPUT_ON_FAILURE=1
    if [ -n "$TEST_NAME" ]; then
        ( cd "$BUILD_DIR" && ctest -R "$TEST_NAME" )
    else
        ( cd "$BUILD_DIR" && ctest )
    fi
}

build_target() {
    if [ "$TARGET" = "lagom" ]; then
        # Ensure that all lagom binaries get built, in case user first
        # invoked superbuild for serenity target that doesn't set -DBUILD_LAGOM=ON
        local EXTRA_CMAKE_ARGS=""
        if [ "${CMD_ARGS[0]}" = "ladybird" ]; then
            EXTRA_CMAKE_ARGS="-DENABLE_LAGOM_LADYBIRD=ON"
        fi
        cmake -S "$SERENITY_SOURCE_DIR/Meta/Lagom" -B "$BUILD_DIR" -DBUILD_LAGOM=ON ${EXTRA_CMAKE_ARGS}
    fi

    # Get either the environment MAKEJOBS or all processors via CMake
    [ -z "$MAKEJOBS" ] && MAKEJOBS=$(cmake -P "$SERENITY_SOURCE_DIR/Meta/CMake/processor-count.cmake")

    # With zero args, we are doing a standard "build"
    # With multiple args, we are doing an install/image/run
    if [ $# -eq 0 ]; then
        CMAKE_BUILD_PARALLEL_LEVEL="$MAKEJOBS" cmake --build "$SUPER_BUILD_DIR"
    else
        ninja -j "$MAKEJOBS" -C "$BUILD_DIR" -- "$@"
    fi
}

build_image() {
    if [ "$SERENITY_RUN" = "limine" ]; then
        build_target limine-image
    else
        build_target qemu-image
    fi
}

delete_target() {
    [ ! -d "$BUILD_DIR" ] || rm -rf "$BUILD_DIR"
    [ ! -d "$SUPER_BUILD_DIR" ] || rm -rf "$SUPER_BUILD_DIR"
}

build_cmake() {
    echo "CMake version too old: build_cmake"
    ( cd "$SERENITY_SOURCE_DIR/Toolchain" && ./BuildCMake.sh )
}

build_toolchain() {
    echo "build_toolchain: $TOOLCHAIN_DIR"
    if [ "$TOOLCHAIN_TYPE" = "Clang" ]; then
        ( cd "$SERENITY_SOURCE_DIR/Toolchain" && ./BuildClang.sh )
    else
        ( cd "$SERENITY_SOURCE_DIR/Toolchain" && ARCH="$TARGET" ./BuildIt.sh )
    fi
}

ensure_toolchain() {
    if [ "$(cmake -P "$SERENITY_SOURCE_DIR"/Meta/CMake/cmake-version.cmake)" -ne 1 ]; then
        build_cmake
    fi
    [ -d "$TOOLCHAIN_DIR" ] || build_toolchain

    if [ "$TOOLCHAIN_TYPE" = "GNU" ]; then
        local ld_version
        ld_version="$("$TOOLCHAIN_DIR"/bin/"$TARGET"-pc-serenity-ld -v)"
        local expected_version="GNU ld (GNU Binutils) 2.40"
        if [ "$ld_version" != "$expected_version" ]; then
            echo "Your toolchain has an old version of binutils installed."
            echo "    installed version: \"$ld_version\""
            echo "    expected version:  \"$expected_version\""
            echo "Please run $ARG0 rebuild-toolchain $TARGET to update it."
            exit 1
        fi
    fi

}

confirm_rebuild_if_toolchain_exists() {
    [ ! -d "$TOOLCHAIN_DIR" ] && return

    read -rp "You already have a toolchain, are you sure you want to delete and rebuild one [y/N]? " input

    if [[ "$input" != "y" && "$input" != "Y" ]]; then
        die "Aborted rebuild"
    fi
}

delete_toolchain() {
    [ ! -d "$TOOLCHAIN_DIR" ] || rm -rf "$TOOLCHAIN_DIR"
}

kill_tmux_session() {
    local TMUX_SESSION
    TMUX_SESSION="$(tmux display-message -p '#S')"
    [ -z "$TMUX_SESSION" ] || tmux kill-session -t "$TMUX_SESSION"
}

set_tmux_title() {
    printf "\033]2;%s\033\\" "$1"
}

lagom_unsupported() {
    [ "$TARGET" != "lagom" ] || die "${1:-"Command '$CMD' not supported for the lagom target"}"
}

run_gdb() {
    local GDB_ARGS=()
    local PASS_ARG_TO_GDB=""
    local KERNEL_CMD_LINE=""
    local LAGOM_EXECUTABLE=""
    for arg in "${CMD_ARGS[@]}"; do
        if [ "$PASS_ARG_TO_GDB" != "" ]; then
            GDB_ARGS+=( "$PASS_ARG_TO_GDB" "$arg" )
            PASS_ARG_TO_GDB=""
        elif [ "$arg" = "-ex" ]; then
            PASS_ARG_TO_GDB="$arg"
        elif [[ "$arg" =~ ^-.*$ ]]; then
            die "Don't know how to handle argument: $arg"
        else
            if [ "$TARGET" = "lagom" ]; then
                if [ "$LAGOM_EXECUTABLE" != "" ]; then
                    die "Lagom executable can't be specified more than once"
                fi
                LAGOM_EXECUTABLE="$arg"
                if [ "$LAGOM_EXECUTABLE" = "ladybird" ]; then
                    LAGOM_EXECUTABLE="Ladybird/ladybird"
                    # FIXME: Make ladybird less cwd-dependent while in the build directory
                    cd "$BUILD_DIR/Ladybird"
                fi
            else
                if [ "$KERNEL_CMD_LINE" != "" ]; then
                    die "Kernel command line can't be specified more than once"
                fi
                KERNEL_CMD_LINE="$arg"
            fi
        fi
    done
    if [ "$PASS_ARG_TO_GDB" != "" ]; then
        GDB_ARGS+=( "$PASS_ARG_TO_GDB" )
    fi
    if [ "$TARGET" = "lagom" ]; then
        gdb "$BUILD_DIR/$LAGOM_EXECUTABLE" "${GDB_ARGS[@]}"
    else
        if [ -n "$KERNEL_CMD_LINE" ]; then
            export SERENITY_KERNEL_CMDLINE="$KERNEL_CMD_LINE"
        fi
        sleep 1
        "$(get_top_dir)/Meta/debug-kernel.sh" "${GDB_ARGS[@]}"
    fi
}

build_and_run_lagom_target() {
    local run_target="${1}"
    local lagom_target="${CMD_ARGS[0]}"
    local lagom_args

    # All command arguments must have any existing semicolon escaped, to prevent CMake from
    # interpreting them as list separators.
    local cmd_args=()
    for arg in "${CMD_ARGS[@]:1}"; do
        cmd_args+=( "${arg//;/\\;}" )
    done

    # Then existing list separators must be replaced with a semicolon for CMake.
    lagom_args=$(IFS=';' ; echo -e "${cmd_args[*]}")

    LAGOM_TARGET="${lagom_target}" LAGOM_ARGS="${lagom_args[*]}" build_target "${run_target}"
}

if [[ "$CMD" =~ ^(build|install|image|copy-src|run|gdb|test|rebuild|recreate|kaddr2line|addr2line|setup-and-run)$ ]]; then
    cmd_with_target
    [[ "$CMD" != "recreate" && "$CMD" != "rebuild" ]] || delete_target
    [ "$TARGET" = "lagom" ] || ensure_toolchain
    ensure_target
    case "$CMD" in
        build)
            build_target "$@"
            ;;
        install)
            build_target
            build_target install
            ;;
        image)
            lagom_unsupported
            build_target
            build_target install
            build_image
            ;;
        copy-src)
          lagom_unsupported
          build_target
          build_target install
          export SERENITY_COPY_SOURCE=1
          build_image
          ;;
        run)
            if [ "$TARGET" = "lagom" ]; then
                if [ "${CMD_ARGS[0]}" = "ladybird" ]; then
                    build_and_run_lagom_target "run-ladybird"
                else
                    build_and_run_lagom_target "run-lagom-target"
                fi
            else
                build_target
                build_target install
                build_image
                if [ -n "${CMD_ARGS[0]}" ]; then
                    export SERENITY_KERNEL_CMDLINE="${CMD_ARGS[0]}"
                fi
                build_target run
            fi
            ;;
        gdb)
            if [ "$TARGET" = "lagom" ]; then
                [ $# -ge 1 ] || usage
                build_target "$@"
                run_gdb "${CMD_ARGS[@]}"
            else
                command -v tmux >/dev/null 2>&1 || die "Please install tmux!"
                build_target
                build_target install
                build_image
                tmux new-session "$ARG0" __tmux_cmd "$TARGET" "$TOOLCHAIN_TYPE" run "${CMD_ARGS[@]}" \; set-option -t 0 mouse on \; split-window "$ARG0" __tmux_cmd "$TARGET" "$TOOLCHAIN_TYPE" gdb "${CMD_ARGS[@]}" \;
            fi
            ;;
        test)
            build_target
            if [ "$TARGET" = "lagom" ]; then
                run_tests "${CMD_ARGS[0]}"
            else
                build_target install
                build_image
                # In contrast to CI, we don't set 'panic=shutdown' here,
                # in case the user wants to inspect qemu some more.
                export SERENITY_KERNEL_CMDLINE="graphics_subsystem_mode=off system_mode=self-test"
                export SERENITY_RUN="ci"
                build_target run
            fi
            ;;
        rebuild)
            build_target "$@"
            ;;
        recreate)
            ;;
        kaddr2line)
            lagom_unsupported
            build_target
            [ $# -ge 1 ] || usage
            if [ "$TOOLCHAIN_TYPE" = "Clang" ]; then
                ADDR2LINE="$TOOLCHAIN_DIR/bin/llvm-addr2line"
            else
                ADDR2LINE="$TOOLCHAIN_DIR/bin/$TARGET-pc-serenity-addr2line"
            fi
            "$ADDR2LINE" -e "$BUILD_DIR/Kernel/Kernel" "$@"
            ;;
        addr2line)
            build_target
            [ $# -ge 2 ] || usage
            BINARY_FILE="$1"; shift
            BINARY_FILE_PATH="$BUILD_DIR/$BINARY_FILE"
            if [ "$TARGET" = "lagom" ]; then
                command -v addr2line >/dev/null 2>&1 || die "Please install addr2line!"
                ADDR2LINE=addr2line
            elif [ "$TOOLCHAIN_TYPE" = "Clang" ]; then
                ADDR2LINE="$TOOLCHAIN_DIR/bin/llvm-addr2line"
            else
                ADDR2LINE="$TOOLCHAIN_DIR/bin/$TARGET-pc-serenity-addr2line"
            fi
            if [ -x "$BINARY_FILE_PATH" ]; then
                "$ADDR2LINE" -e "$BINARY_FILE_PATH" "$@"
            else
                find "$BUILD_DIR" -name "$BINARY_FILE" -executable -type f -exec "$ADDR2LINE" -e {} "$@" \;
            fi
            ;;
        *)
            build_target "$CMD" "$@"
            ;;
    esac
elif [ "$CMD" = "delete" ]; then
    cmd_with_target
    delete_target
elif [ "$CMD" = "rebuild-toolchain" ]; then
    cmd_with_target
    lagom_unsupported "The lagom target uses the host toolchain"
    confirm_rebuild_if_toolchain_exists
    delete_toolchain
    ensure_toolchain
elif [ "$CMD" = "rebuild-world" ]; then
    cmd_with_target
    lagom_unsupported "The lagom target uses the host toolchain"
    delete_toolchain
    delete_target
    ensure_toolchain
    ensure_target
    build_target
elif [ "$CMD" = "__tmux_cmd" ]; then
    trap kill_tmux_session EXIT
    cmd_with_target
    CMD="$1"; shift
    CMD_ARGS=("${CMD_ARGS[@]:1}")
    if [ "$CMD" = "run" ]; then
        if [ -n "${CMD_ARGS[0]}" ]; then
            export SERENITY_KERNEL_CMDLINE="${CMD_ARGS[0]}"
        fi
        # We need to make sure qemu doesn't start until we continue in gdb
        export SERENITY_EXTRA_QEMU_ARGS="${SERENITY_EXTRA_QEMU_ARGS} -d int -no-reboot -no-shutdown -S"
        # We need to disable kaslr to let gdb map the kernel symbols correctly
        export SERENITY_KERNEL_CMDLINE="${SERENITY_KERNEL_CMDLINE} disable_kaslr"
        set_tmux_title 'qemu'
        build_target run
    elif [ "$CMD" = "gdb" ]; then
        set_tmux_title 'gdb'
        run_gdb "${CMD_ARGS[@]}"
    fi
else
    >&2 echo "Unknown command: $CMD"
    usage
fi