#!/bin/sh

set -e

# Function to display usage
usage() {
  echo "Install or upgrade a Mithril node"
  echo "Usage: $0 [-c node] [-v version] [-d distribution] [-p path]"
  echo "  -c node          : Mithril node to install or upgrade (mithril-signer, mithril-aggregator, mithril-client)"
  echo "  -d distribution  : Distribution to upgrade to (latest, unstable or distribution version e.g '2445.0')"
  echo "  -p path          : Path to install the component"
  echo "Environment variables:"
  echo "  GITHUB_TOKEN     : Optional GitHub token used to raise the GitHub API rate limit"
  exit 1
}

# Function to display an error message and exit
error_exit() {
  echo "$1" 1>&2
  exit 1
}

# Function to check that required tools are installed
check_requirements() {
    which curl >/dev/null ||
        error_exit "It seems 'curl' is not installed or not in the path.";
    which jq >/dev/null ||
        error_exit "It seems 'jq' is not installed or not in the path.";
}

check_glibc_min_version() {
  glibc_version=$(ldd --version | awk 'NR==1{print $NF}')

  if [ "$(echo "$glibc_version" | grep -cE -e "2\.[0-2][0-9]" -e "2\.3[0-4]")" -gt 0 ]; then
    error_exit "Error: Your GLIBC version is $glibc_version, but the minimum required version is 2.35."
  fi
}

# Function to fetch the release information, with retries on transient errors and accurate error reporting
fetch_release_information() {
  release_url=$1
  destination_file=$2
  max_attempts=3
  retry_delay=3

  attempt=1
  while [ "$attempt" -le "$max_attempts" ]; do
    if [ -n "$GITHUB_TOKEN" ]; then
      http_code=$(curl -sL -o "$destination_file" -w '%{http_code}' -H "Authorization: Bearer $GITHUB_TOKEN" "$release_url") || http_code="000"
    else
      http_code=$(curl -sL -o "$destination_file" -w '%{http_code}' "$release_url") || http_code="000"
    fi

    case "$http_code" in
      2*)
        return 0
        ;;
      403 | 429)
        error_exit "Error: GitHub API rate limit exceeded. Retry later or set the 'GITHUB_TOKEN' environment variable to raise the limit."
        ;;
      404)
        error_exit "Error: The distribution '$DISTRIBUTION' does not exist."
        ;;
      4*)
        error_exit "Error: Failed to fetch the release information (HTTP status $http_code)."
        ;;
    esac

    if [ "$attempt" -lt "$max_attempts" ]; then
      echo "Attempt $attempt to fetch the release information failed (HTTP status $http_code). Retrying in $retry_delay seconds..." 1>&2
      sleep "$retry_delay"
    fi
    attempt=$((attempt + 1))
  done

  error_exit "Error: Failed to fetch the release information after $max_attempts attempts (last HTTP status $http_code)."
}

# --- MAIN execution ---

# Default values
DISTRIBUTION="latest"
GITHUB_ORGANIZATION="IntersectMBO"
GITHUB_REPOSITORY="mithril"

check_requirements

# Parse command line arguments
while getopts "c:v:d:p:" opt; do
  case ${opt} in
    c )
      NODE=$OPTARG
      ;;
    d )
      DISTRIBUTION=$OPTARG
      ;;
    p )
      INSTALL_PATH=$OPTARG
      ;;
    * )
      usage
      ;;
  esac
done

# Detect the operating system
OS=$(uname -s)
OS_CODE=$(echo "$OS" | awk '{print tolower($0)}')

case "$OS" in
  Linux) : ;;
  Darwin) OS_CODE="macos" ;;
  *) error_exit "Unsupported operating system $OS for $NODE" ;;
esac

# Detect the architecture
ARCH=$(uname -m)

case "$ARCH" in
  x86_64)
    ARCH_NAME="x64"
    ;;
  arm64|aarch64)
    ARCH_NAME="arm64"
    ;;
  *)
    error_exit "Unsupported architecture: $ARCH"
    ;;
esac

# Set temp file
TEMP_FILE="${INSTALL_PATH}/temp.json"

# Check if node and path are provided
if [ -z "$NODE" ] || [ -z "$DISTRIBUTION" ] || [ -z "$INSTALL_PATH" ]; then
  usage
fi

# Create the install path if it doesn't exist
mkdir -p "$INSTALL_PATH"

# Check if install path is writable
if [ ! -w "$INSTALL_PATH" ]; then
  error_exit "Error: The specified install path '$INSTALL_PATH' is not writable."
fi

# Validate node
if [ "$NODE" != "mithril-signer" ] && [ "$NODE" != "mithril-aggregator" ] && [ "$NODE" != "mithril-client" ]; then
  echo "Invalid node: $NODE"
  usage
fi

# Determine the URL for the specified tag
if [ "$DISTRIBUTION" = "latest" ]; then
  RELEASE_URL="https://api.github.com/repos/${GITHUB_ORGANIZATION}/${GITHUB_REPOSITORY}/releases/latest"
else
  RELEASE_URL="https://api.github.com/repos/${GITHUB_ORGANIZATION}/${GITHUB_REPOSITORY}/releases/tags/${DISTRIBUTION}"
fi

# Fetch the release information
echo "Fetching release information from $RELEASE_URL..."
fetch_release_information "$RELEASE_URL" "$TEMP_FILE"

# Find valid binary for the node
ASSETS_DOWNLOAD_URL=$(jq -r --arg os_code "$OS_CODE" --arg arch_name "$ARCH_NAME" '.assets[] | select(.name | contains($os_code)) | select(.name | contains($arch_name)) | .browser_download_url' < "$TEMP_FILE")
rm -f "$TEMP_FILE"
if [ -z "$ASSETS_DOWNLOAD_URL" ]; then
  error_exit "Error: Failed to fetch assets from release. This probably means that your OS and architecture are not supported."
fi

# Download the distribution assets
echo "Downloading $NODE to $DISTRIBUTION from $ASSETS_DOWNLOAD_URL..."
ASSETS_FILE_PATH="$INSTALL_PATH/mithril-assets.tar.gz"
curl --fail -sL -o "$ASSETS_FILE_PATH" "$ASSETS_DOWNLOAD_URL" || error_exit "Error: Failed to download the asset file from the release"

# Search for a node file
NODE_FILE_NAME=$(tar -tzf "$ASSETS_FILE_PATH" | grep "$NODE" | awk '{print $NF}')
if [ -z "$NODE_FILE_NAME" ]; then
  error_exit "Error: Failed to find $NODE binary in the distribution asset. This probably means that your OS and architecture are not supported."
fi

tar -xz -f "$ASSETS_FILE_PATH" -C "$INSTALL_PATH" "$NODE"
chmod +x "$INSTALL_PATH/$NODE"
rm -f "$ASSETS_FILE_PATH"

# Check glibc version if the binary is dynamic
if [ "$OS" = "Linux" ]; then
  LDD_OUTPUT=$(ldd "$INSTALL_PATH/$NODE" 2>&1 || true)
  if echo "$LDD_OUTPUT" | grep -Eq "statically linked|not a dynamic executable"; then
    echo "Binary is static, skipping glibc check."
  else
    echo "Checking glibc version"
    check_glibc_min_version
  fi
fi

VERSION_OUTPUT=$("$INSTALL_PATH/$NODE" --version)
VERSION=$(echo "$VERSION_OUTPUT" | awk '{print $NF}')
echo "Congrats! ${NODE} has been upgraded to ${VERSION} from distribution ${DISTRIBUTION} and installed at ${INSTALL_PATH}!"