#!/usr/bin/env bash

main() {
    # Required to add the AAS metadata
    export DD_AZURE_APP_SERVICES=1
    export DD_HOSTNAME="none"

    CURRENT_DIR=$(pwd)
    echo "Set application directory as $CURRENT_DIR"

    echo "Setting Datadog environment variables"
    setEnvVars

    echo "Creating and switching to the Datadog directory at $DD_DIR"
    mkdir -p "$DD_DIR" && cd "$DD_DIR" || return

    echo "Adding Runtime specific dependencies"
    getRuntimeDependencies

    echo "Getting the Datadog binaries"
    getBinaries

    echo "Starting the appropriate Datadog bianries"
    startBinaries

    case "$WEBSITE_STACK" in
        "NODE")
            setUpNodeEnv;;
        "DOTNETCORE")
            setUpDotnetEnv;;
        "JAVA")
            setUpJavaEnv;;
        "PHP")
            setupPHPEnv;;
        "PYTHON")
            setUpPyEnv;;
        "TOMCAT")
            setUpJavaEnv;;
        "*")
            echo "Unsupported runtime. Exiting Datadog startup"
            return;;
    esac

    echo "Removing any previous installations"
    find "$DD_DIR"/v* -type d | grep -v "$DD_BINARY_DIR" | xargs -r rm -r

    echo "Completed Datadog setup"
}

setEnvVars() {
    if [ -z "$DD_DIR" ]; then
        DD_DIR="/home/datadog"
    fi

    if [ -z "$DD_BINARIES_URL" ]; then
        DD_BINARIES_URL="https://github.com/DataDog/datadog-aas-linux/releases/download"
    fi

    if [ -z "$DD_AAS_LINUX_VERSION" ]; then
        DD_AAS_LINUX_VERSION="v1.3.0"
    fi

    if [ -z "$DD_BINARY_DIR" ]; then
        DD_BINARY_DIR="${DD_DIR}/${DD_AAS_LINUX_VERSION}"
    fi

    if [ -z "$DD_TRACE_ENABLED" ]; then
        DD_TRACE_ENABLED="true"
    fi

    if [ -z "$DD_CUSTOM_METRICS_ENABLED" ]; then
        DD_CUSTOM_METRICS_ENABLED="false"
    fi

    if [ -z "$DD_LOG_LEVEL" ]; then
        DD_LOG_LEVEL="error"
    fi

}

getRuntimeDependencies() {
    if [ "$WEBSITE_STACK" == "TOMCAT" ]; then
        DD_TOMCAT_VERSION=$(echo "$TOMCAT_VERSION" | awk -F. '{print $1}')
    fi

    if [ "$WEBSITE_STACK" == "PHP" ] || [ "$WEBSITE_STACK" == "JAVA" ] || [ "$DD_TOMCAT_VERSION" == "10" ]; then
        apt-get update && apt-get install -y unzip
    fi

    if [ "$DD_TOMCAT_VERSION" == "9" ]; then
        apk add curl
        apk add libc6-compat
    fi
}

getBinaries() {
    #Check if we have already installed this version
    if [ ! -d "$DD_BINARY_DIR" ]; then

        FILE="datadog-aas-${DD_AAS_LINUX_VERSION}.zip"

        echo "Downloading Datadog AAS binary $DD_BINARIES_URL/$DD_AAS_LINUX_VERSION/$FILE"
        if curl -L --fail "$DD_BINARIES_URL/$DD_AAS_LINUX_VERSION/$FILE" -o "$FILE"; then
            echo "Unzipping files"
            unzip "$FILE" || return
            echo "Removing zip file"
            rm "$FILE"

        else
            echo "Failed to download the Datadog binary succesfully."
            return
        fi

    else
        echo "Version $DD_AAS_LINUX_VERSION of Datadog AAS previously installed"
    fi
}

startBinaries() {

    BINARY_DIR="${DD_DIR}/${DD_AAS_LINUX_VERSION}"

    if [ "$DD_TRACE_ENABLED" = "true" ]; then
        echo "Starting the trace agent"
        eval "$DD_BINARY_DIR/process_manager $BINARY_DIR/trace-agent &"
    fi

    if [ "$DD_CUSTOM_METRICS_ENABLED" = "true" ]; then
        echo "Starting DogStatsD"
        eval "$DD_BINARY_DIR/process_manager $BINARY_DIR/dogstatsd start &"
    fi
}

setUpNodeEnv() {
    echo "Setting up Datadog tracing for Node"
    echo "Installing Node tracer"
    yarn add dd-trace || return

    ORIG_NODE_OPTIONS=$NODE_OPTIONS
    export NODE_OPTIONS="--require=$DD_DIR/node_modules/dd-trace/init $ORIG_NODE_OPTIONS"

    # confirm updates to NODE_OPTIONS
    node --help >/dev/null || (export NODE_OPTIONS="$ORIG_NODE_OPTIONS" && return)
}

setUpDotnetEnv() {
    echo "Setting up Datadog tracing for .NET"
    if [ -z "$DD_DOTNET_TRACER_VERSION" ]; then
        DD_DOTNET_TRACER_VERSION=2.19.0
    fi
    DD_DOTNET_TRACER_FILE=datadog-dotnet-apm-${DD_DOTNET_TRACER_VERSION}.tar.gz
    DD_DOTNET_TRACER_URL=https://github.com/DataDog/dd-trace-dotnet/releases/download/v${DD_DOTNET_TRACER_VERSION}/${DD_DOTNET_TRACER_FILE}

    echo "Installing .NET tracer from $DD_DOTNET_TRACER_URL"
    if curl -L --fail "$DD_DOTNET_TRACER_URL" -o "$DD_DOTNET_TRACER_FILE"; then
        tar -xzf "$DD_DOTNET_TRACER_FILE" || return
    else
        echo "Downloading the tracer was unsuccessful"
        return
    fi

    export CORECLR_ENABLE_PROFILING=1
    export CORECLR_PROFILER="{846F5F1C-F9AE-4B07-969E-05C26BC060D8}"
    export CORECLR_PROFILER_PATH="${DD_DIR}/Datadog.Trace.ClrProfiler.Native.so"
    export DD_DOTNET_TRACER_HOME="${DD_DIR}"
}

setUpJavaEnv() {
    echo "Setting up Datadog tracing for Java"
    if [ -z "$DD_JAVA_TRACER_VERSION" ]; then
        DD_JAVA_TRACER_VERSION=1.4.0
    fi

    echo "Using version $DD_JAVA_TRACER_VERSION of the JAVA tracer"
    DD_JAVA_TRACER_FILE="dd-java-agent-$DD_JAVA_TRACER_VERSION.jar"
    DD_JAVA_TRACER_URL="https://github.com/DataDog/dd-trace-java/releases/download/v$DD_JAVA_TRACER_VERSION/$DD_JAVA_TRACER_FILE"

    echo "Installing JAVA tracer from $DD_JAVA_TRACER_URL"
    if ! curl -L --fail "$DD_JAVA_TRACER_URL" -o "$DD_JAVA_TRACER_FILE"; then
        echo "Downloading the tracer was unsuccessful"
        return
    fi

    echo "Adding the JAVA tracer to the startup command"
    DD_JAVAAGENT="-javaagent:$DD_DIR/$DD_JAVA_TRACER_FILE"

    if [ "$WEBSITE_STACK" == "TOMCAT" ]; then
        export JAVA_OPTS="$JAVA_OPTS $DD_JAVAAGENT"
    else
        DD_START_APP=$(echo "${DD_START_APP//-jar/$DD_JAVAAGENT -jar}")
    fi
}

setupPHPEnv() {
    echo "Setting up Datadog tracing for PHP"
    if [ -z "$DD_PHP_TRACER_VERSION" ]; then
        DD_PHP_TRACER_VERSION=0.83.1
    fi

    DD_PHP_TRACER_URL=https://github.com/DataDog/dd-trace-php/releases/download/${DD_PHP_TRACER_VERSION}/datadog-setup.php

    echo "Installing PHP tracer from $DD_PHP_TRACER_URL"
    if curl -LO --fail "$DD_PHP_TRACER_URL"; then
        eval "php datadog-setup.php --php-bin=all"
    else
        echo "Downloading the tracer was unsuccessful"
        return
    fi
}

setUpPyEnv() {
    echo "Setting up Datadog tracing for Python"
    if [ -z "$DD_PYTHON_TRACER_VERSION" ]; then
        DD_PYTHON_TRACER_VERSION=1.7.0
    fi

    pip install ddtrace
    # append ddtrace-run command to original start command
    DD_START_APP="ddtrace-run ${DD_START_APP}"
}

main
echo "Executing start command: \"$DD_START_APP\""
cd "$CURRENT_DIR"
eval "$DD_START_APP"