#!/bin/bash
# This is an entrypoint for our Docker image that does some minimal bootstrapping before executing.

set -e

# If the PULUMI_CI variable is set, we'll do some extra things to make common tasks easier.
if [ ! -z "$PULUMI_CI" ]; then
    # Detect the CI system and configure variables so that we get good Pulumi workflow and GitHub App support.
    if [ ! -z "$GITHUB_WORKFLOW" ]; then
        export PULUMI_CI_SYSTEM="GitHub"
        export PULUMI_CI_BUILD_ID=
        export PULUMI_CI_BUILD_TYPE=
        export PULUMI_CI_BUILD_URL=
        export PULUMI_CI_PULL_REQUEST_SHA="$GITHUB_SHA"

        # For PR events, we want to take the ref of the target branch, not the current. This ensures, for
        # instance, that a PR for a topic branch merging into `master` will use the `master` branch as the
        # target for a preview. Note that for push events, we of course want to use the actual branch.
        if [ "$PULUMI_CI" = "pr" ]; then
            # Not all PR events warrant running a preview. Many of them pertain to changes in assignments
            # and ownership, but we only want to run the preview if the action is "opened" or "edited".
            PR_ACTION=$(jq -r ".action" < $GITHUB_EVENT_PATH)
            if [ "$PR_ACTION" != "opened" ] && [ "$PR_ACTION" != "edited" ]; then
                echo -e "PR event ($PR_ACTION) contains no changes and does not warrant a Pulumi Preview"
                echo -e "Skipping Pulumi action altogether..."
                exit 0
            fi

            BRANCH=$(jq -r ".pull_request.base.ref" < $GITHUB_EVENT_PATH)
        else
            BRANCH="$GITHUB_REF"
        fi
        BRANCH=$(echo $BRANCH | sed "s/refs\/heads\///g")
    fi

    # Respect the branch mappings file for stack selection. Note that this is *not* required, but if the file
    # is missing, the caller of this script will need to pass `-s <stack-name>` to specify the stack explicitly.
    if [ ! -z "$BRANCH" ] && [ -e .pulumi/ci.json ]; then
        PULUMI_STACK_NAME=$(cat .pulumi/ci.json | jq -r ".\"$BRANCH\"")
        if [ "$PULUMI_STACK_NAME" != "null" ]; then
            pulumi stack select $PULUMI_STACK_NAME
        else
            echo -e "No stack configured for branch '$BRANCH'"
            echo -e ""
            echo -e "To configure this branch, please"
            echo -e "\t1) Run 'pulumi stack init <stack-name>'"
            echo -e "\t2) Associated the stack with the branch by adding"
            echo -e "\t\t{"
            echo -e "\t\t\t\"$BRANCH\": \"<stack-name>\""
            echo -e "\t\t}"
            echo -e "\tto your .pulumi/ci.json file"
            echo -e ""
            echo -e "For now, exiting cleanly without doing anything..."
            exit 0
        fi
    fi
fi

# Next, lazily install packages if required.
if [ -e package.json ] && [ ! -d node_modules ]; then
    npm install
fi

# Now just pass along all arguments to the Pulumi CLI.
pulumi "$@"