#!/usr/bin/env bash
#
# Author: Stefan Buck
# License: MIT
# https://gist.github.com/stefanbuck/ce788fee19ab6eb0b4447a85fc99f447
#
#
# This script accepts the following parameters:
#
# * owner
# * repo
# * tag
# * filename
# * github_api_token
# * overwrite (optional, could be ture, false, delete, default to be false)
#
# Script to upload a release asset using the GitHub API v3.
#
# Example:
#
# upload-github-release-asset.sh github_api_token=TOKEN owner=stefanbuck repo=playground tag=v0.1.0 filename=./build.zip overwrite=true
#

# Check dependencies.
set -e
xargs=$(which gxargs || which xargs)

# Validate settings.
[ "$TRACE" ] && set -x

CONFIG=$@

for line in $CONFIG; do
  eval "$line"
done

# Define variables.
GH_API="https://api.github.com"
GH_REPO="$GH_API/repos/$owner/$repo"
GH_TAGS="$GH_REPO/releases/tags/$tag"
AUTH="Authorization: token $github_api_token"
WGET_ARGS="--content-disposition --auth-no-challenge --no-cookie"
CURL_ARGS="-LJO#"

if [[ "$tag" == 'LATEST' ]]; then
  GH_TAGS="$GH_REPO/releases/latest"
fi

# Validate token.
curl -o /dev/null -sH "$AUTH" $GH_REPO || { echo "Error: Invalid repo, token or network issue!";  exit 1; }

# Read asset tags.
response=$(curl -sH "$AUTH" $GH_TAGS)

# Get ID of the release.
eval $(echo "$response" | grep -m 1 "id.:" | grep -w id | tr : = | tr -cd '[[:alnum:]]=' | sed 's/id/release_id/')
[ "$release_id"  ] || { echo "Error: Failed to get release id for tag: $tag"; echo "$response" | awk 'length($0)<100' >&2; exit 1; }

# Get ID of the asset based on given filename.
# If exists, delete it.
eval $(echo "$response" | grep -C2 "\"name\":.\+$(basename $filename)" | grep -m 1 "id.:" | grep -w id | tr : = | tr -cd '[[:alnum:]]=' | sed 's/id/asset_id/')
if [ "$asset_id" = ""  ]; then
    echo "No need to overwrite asset"
else
    if [[ "$overwrite" == "true" ]] || [[ "$overwrite" == "delete" ]]; then
        echo "Deleting asset($asset_id)... "
        curl  -X "DELETE" -H "Authorization: token $github_api_token" "https://api.github.com/repos/$owner/$repo/releases/assets/$asset_id"
        if [[ "$overwrite" == "delete" ]]; then
            exit 0
        fi
    else
        echo "File already exists on tag $tag"
        echo "If you want to overwrite it, set overwrite=true"
        exit 1
    fi
fi

# Upload asset
echo "Uploading asset... "

# Construct url
GH_ASSET="https://uploads.github.com/repos/$owner/$repo/releases/$release_id/assets?name=$(basename $filename)"

curl --data-binary @"$filename" -H "Authorization: token $github_api_token" -H "Content-Type: application/octet-stream" $GH_ASSET