#!/bin/sh -e

CURRENT_GO_PATH=$(which go)

if [ -z "$CURRENT_GO_PATH" ]; then
    echo "Go is not installed!"
    CURRENT_GO_PATH=$(echo $GOROOT)
    if [ -z "$CURRENT_GO_PATH" ]; then
        CURRENT_GO_PATH="/usr/local/go"
    else
        CURRENT_GO_PATH="$CURRENT_GO_PATH"
    fi
    echo "Installing Go in $CURRENT_GO_PATH"
else
    echo "Found Go in $CURRENT_GO_PATH"
    echo "Updating Go in $CURRENT_GO_PATH"
fi

BASE_GO_PATH=$(echo $CURRENT_GO_PATH | sed 's/\/bin\/go//g')
ROOT_GO_PATH=$(echo $BASE_GO_PATH | sed 's/\/go//g')
# echo "Current Go path: $CURRENT_GO_PATH | Base Go path: $BASE_GO_PATH | Root Go path: $ROOT_GO_PATH"

#UPDATE_GO_VERSION=${1:-}
FETCH_FROM_GO_VERSION=$(curl -s https://go.dev/VERSION?m=text | awk 'NR==1 {sub(/^go/, ""); print}')
# Output:
# go1.21.0
# time 2023-08-04T20:14:06Z
UPDATE_GO_VERSION=$(echo $FETCH_FROM_GO_VERSION)
echo "Latest fetched from: https://go.dev/VERSION => $UPDATE_GO_VERSION"

# UPDATE_GO_VERSION=$(echo $FETCH_FROM_GO_VERSION | sed 's/^go//')

if [ -z "$UPDATE_GO_VERSION" ]; then
    echo "Usage: $0 <go-version> | Example: $0 1.20.0"
    exit 1
fi

CURRENT_GO_VERSION=$(go version | awk '{print $3}')
echo "Checking version $UPDATE_GO_VERSION in local..."

if [ "go$UPDATE_GO_VERSION" = "$CURRENT_GO_VERSION" ]; then
    echo "Version $UPDATE_GO_VERSION is already installed!"
    exit 0
else
    echo "New version $UPDATE_GO_VERSION is available!"
fi

GO_FILE="go${UPDATE_GO_VERSION}.linux-amd64.tar.gz"
GO_DL_URL=https://go.dev/dl/$GO_FILE

echo "Downloading last version from $GO_DL_URL"
sudo wget $GO_DL_URL -O /tmp/$GO_FILE

echo "Remove old version: $CURRENT_GO_VERSION from $BASE_GO_PATH"
sudo rm -rf $BASE_GO_PATH

echo "Extracting new version: $UPDATE_GO_VERSION"
sudo tar -C $ROOT_GO_PATH -xzf /tmp/$GO_FILE

echo "Removing downloaded file: $GO_FILE"
sudo rm -rf /tmp/$GO_FILE

echo "Verifying new version: $UPDATE_GO_VERSION"
if [ "go$UPDATE_GO_VERSION" = "$(go version | awk '{print $3}')" ]; then
    echo "New version $UPDATE_GO_VERSION is installed!"
else
    echo "New version $UPDATE_GO_VERSION is not installed!"
fi

echo "Thanks for using go-update!"