#!/bin/bash

set -e
set -o pipefail

source_root="$(dirname "$0")"

# Set to "latest" for the latest build.
: ${REALM_CORE_VERSION:=$(sed -n 's/^REALM_CORE_VERSION=\(.*\)$/\1/p' ${source_root}/../dependencies.list)}
: ${REALM_SYNC_VERSION:=$(sed -n 's/^REALM_SYNC_VERSION=\(.*\)$/\1/p' ${source_root}/../dependencies.list)}

if [ "$1" = '--version' ]; then
    echo "$REALM_CORE_VERSION"
    exit 0
elif [ "$1" = '--versionSync' ]; then
    echo "$REALM_SYNC_VERSION"
    exit 0
fi

# The 'node' argument will result in realm-node build being downloaded.
if [ "$1" = 'node' ]; then
    ENABLE_SYNC="$2"
    CORE_DIR="realm-node"
    SYNC_DIR='realm-node'

    if [ "$(uname)" = 'Darwin' ]; then
        PLATFORM_TAG="node-osx-"
        SYNC_PLATFORM_TAG="node-cocoa-"
        CORE_DOWNLOAD_FILE="realm-core-node-osx-$REALM_CORE_VERSION.tar.gz"
        SYNC_DOWNLOAD_FILE="realm-sync-$SYNC_PLATFORM_TAG$REALM_SYNC_VERSION.tar.gz"
    else
        PLATFORM_TAG="node-linux-"
        SYNC_PLATFORM_TAG="node-cocoa-"
        CORE_DOWNLOAD_FILE="realm-core-node-linux-$REALM_CORE_VERSION.tar.gz"
        SYNC_DOWNLOAD_FILE=""
    fi

    SYNC_EXTRACT="tar -xvf"
    EXTRACTED_DIR="realm-sync-node-cocoa-$REALM_SYNC_VERSION"
else
    ENABLE_SYNC="yes" # FIXME: This means that both core and sync will be downloaded for non "node" targets.
    # Should be 0 or 1. We do not need to download both
    CORE_DIR='core'
    PLATFORM_TAG=""
    SYNC_DIR='sync'
    CORE_DOWNLOAD_FILE="realm-core-$PLATFORM_TAG$REALM_CORE_VERSION.tar.xz"
    SYNC_DOWNLOAD_FILE="realm-sync-cocoa-$SYNC_PLATFORM_TAG$REALM_SYNC_VERSION.tar.xz"
    SYNC_EXTRACT="tar -xvf"
    EXTRACTED_DIR="core"
fi

# Start current working directory at the root of the project.
cd "$(dirname "$0")/.."

die() {
    echo "$@" >&2
    exit 1
}

download_core() {
    local DIR=$1
    local VERSION=$2
    local DOWNLOAD_FILE=$3
    local SERVER_DIR=$4
    local UNTAR=$5
    local UNTARRED_DIR=$6
    echo "Downloading dependency: $DIR $VERSION"

    local TMP_DIR="${TMPDIR:-/tmp}/$DIR"
    local TAR="$TMP_DIR/$DOWNLOAD_FILE"
    local TMP_TAR="$TAR.tmp"

    mkdir -p "$TMP_DIR"

    if [ ! -f "$TAR" ]; then
	echo  "https://static.realm.io/downloads/$SERVER_DIR/$DOWNLOAD_FILE"
        curl -f -L -s "https://static.realm.io/downloads/$SERVER_DIR/$DOWNLOAD_FILE" -o "$TMP_TAR" ||
            die "Downloading $DIR failed. Please try again once you have an Internet connection."
        mv "$TMP_TAR" "$TAR"
    else
        echo "Using cached $DIR from TMPDIR"
    fi

    (
        cd "$TMP_DIR"
        rm -rf "$DIR"
        eval "$UNTAR" "$TAR"
        mv "$UNTARRED_DIR" "$DIR-$VERSION"
    )

    (
        cd vendor
        rm -rf "$DIR-$VERSION" "$DIR"
        mv "$TMP_DIR/$DIR-$VERSION" .
        ln -s "$DIR-$VERSION" "$DIR"
    )
}

check_release_notes() {
    grep -Fqi "$REALM_CORE_VERSION RELEASE NOTES" "$@"
}

check_sync_version() {
    grep -Fqi "$REALM_SYNC_VERSION" "$@"
}

DOWNLOAD_CORE=1

if ! [ -z "$REALM_CORE_PREFIX" ]; then
DOWNLOAD_CORE=0
echo "Skipping the core download because REALM_CORE_PREFIX is defined."
fi

if [ "$ENABLE_SYNC" == 1 ]; then
DOWNLOAD_CORE=0
echo "Skipping the core download because ENABLE_SYNC is true."
fi

if [ "$DOWNLOAD_CORE" == 1 ]; then
    if [ ! -e "vendor/$CORE_DIR" ]; then
        download_core $CORE_DIR $REALM_CORE_VERSION $CORE_DOWNLOAD_FILE core "tar -xzf" core
    elif [ -d "vendor/$CORE_DIR" -a -d ../realm-core -a ! -L "vendor/$CORE_DIR" ]; then
        # Allow newer versions than expected for local builds as testing
        # with unreleased versions is one of the reasons to use a local build
        if ! check_release_notes "vendor/$CORE_DIR/CHANGELOG.txt"; then
            die "Local build of core is out of date."
        else
            echo "The core library seems to be up to date."
        fi
    elif [ ! -L "vendor/$CORE_DIR" ]; then
        echo "vendor/$CORE_DIR is not a symlink. Deleting..."
        rm -rf "vendor/$CORE_DIR"
        download_core $CORE_DIR $REALM_CORE_VERSION $CORE_DOWNLOAD_FILE core "tar -xzf" core
    # With a prebuilt version we only want to check the first non-empty
    # line so that checking out an older commit will download the
    # appropriate version of core if the already-present version is too new
    elif ! grep -m 1 . "vendor/$CORE_DIR/CHANGELOG.txt" | check_release_notes; then
        download_core $CORE_DIR $REALM_CORE_VERSION $CORE_DOWNLOAD_FILE core "tar -xzf" core
    else
        echo "The core library seems to be up to date."
    fi
fi

DOWNLOAD_SYNC=1
if ! [ -z "$REALM_SYNC_PREFIX" ]; then
DOWNLOAD_SYNC=0
echo "Skipping the sync download because REALM_SYNC_PREFIX is defined."
fi

if [ "$ENABLE_SYNC" == 0 ]; then
DOWNLOAD_SYNC=0
echo "Skipping the sync download because ENABLE_SYNC is false."
fi

if [ "$DOWNLOAD_SYNC" == 1 ]; then
    if [ -n "$SYNC_DOWNLOAD_FILE" ];then
        if [ ! -e "vendor/$SYNC_DIR" ]; then
            download_core $SYNC_DIR $REALM_SYNC_VERSION $SYNC_DOWNLOAD_FILE sync "$SYNC_EXTRACT" $EXTRACTED_DIR
        elif [ -d "vendor/$SYNC_DIR" -a -d ../realm-sync -a ! -L "vendor/$SYNC_DIR" ]; then
            # Allow newer versions than expected for local builds as testing
            # with unreleased versions is one of the reasons to use a local build
            if ! check_release_notes "vendor/$SYNC_DIR/version.txt"; then
                die "Local build of sync is out of date."
            else
                echo "The sync library seems to be up to date."
            fi
        elif [ ! -L "vendor/$SYNC_DIR" ]; then
            echo "vendor/$SYNC_DIR is not a symlink. Deleting..."
            rm -rf "vendor/$SYNC_DIR"
            download_core $SYNC_DIR $REALM_SYNC_VERSION $SYNC_DOWNLOAD_FILE sync "$SYNC_EXTRACT" $EXTRACTED_DIR
        # With a prebuilt version we only want to check the first non-empty
        # line so that checking out an older commit will download the
        # appropriate version of core if the already-present version is too new
        elif ! grep -m 1 . "vendor/$SYNC_DIR/version.txt" | check_sync_version; then
            download_core $SYNC_DIR $REALM_SYNC_VERSION $SYNC_DOWNLOAD_FILE sync "$SYNC_EXTRACT" $EXTRACTED_DIR
        else
            echo "The sync library seems to be up to date."
        fi
    fi
fi