#!/bin/sh
set -e

# ==============================================================================
# Global Configuration & Defaults
# ==============================================================================
# Woodpecker settings are passed as PLUGIN_* environment variables
TOKEN="${PLUGIN_TOKEN}"
BASE_BRANCH="${PLUGIN_BASE_BRANCH:-"main"}"
TEMP_BRANCH="${PLUGIN_TEMP_BRANCH:-"release-plz-update"}"
BOT_NAME="${PLUGIN_BOT_NAME:-"release-plz-bot"}"
BOT_EMAIL="${PLUGIN_BOT_EMAIL:-"bot@codeberg.org"}"
COMMIT_MESSAGE="${PLUGIN_COMMIT_MESSAGE:-"chore: release-plz update"}"
PR_TITLE="${PLUGIN_PR_TITLE:-"chore: release-plz update"}"

# Use Woodpecker CI built-in variables
REPO_FULL_NAME="${CI_REPO}" # e.g., "username/repo"
API_URL="https://codeberg.org/api/v1/repos/${REPO_FULL_NAME}"

# ------------------------------------------------------------------------------
# Checks if the required environment variables are provided before running the rest of the script.
# 
# Arguments: None
# ------------------------------------------------------------------------------
validate_environment() {
    if [ -z "$TOKEN" ]; then
        echo "Error: 'token' setting is missing. Please provide a Codeberg Access Token."
        exit 1
    fi
}

# ------------------------------------------------------------------------------
# Executes the release-plz tool to bump versions and generate changelogs based on conventional commits.
# 
# Arguments: None
# ------------------------------------------------------------------------------
run_release_plz() {
    echo "--- Running release-plz update ---"
    release-plz update --verbose --manifest-path="$(pwd)/Cargo.toml"
}

# ------------------------------------------------------------------------------
# Checks the current git workspace to see if release-plz modified any files (like Cargo.toml or CHANGELOG.md).
# 
# Arguments: None
# 
# Returns: 0 (True) if there are modified files, 1 (False) if clean.
# ------------------------------------------------------------------------------
has_changes() {
    if [ -z "$(git status --porcelain)" ]; then
        return 1 # False: No changes
    else
        return 0 # True: Changes exist
    fi
}

# ------------------------------------------------------------------------------
# Configures the git bot identity, commits the modified files,and force-pushes them to a temporary branch on Codeberg.
# 
# Arguments: None
# ------------------------------------------------------------------------------
commit_and_push_changes() {
    echo "Committing changes to branch: $TEMP_BRANCH..."
    git checkout -B "$TEMP_BRANCH"
    git add .

    # Using environment variables temporarily sets the identity for THIS commit only,
    # preventing any accidental overwrites to a developer's global or local git config.
    GIT_AUTHOR_NAME="$BOT_NAME" \
    GIT_AUTHOR_EMAIL="$BOT_EMAIL" \
    GIT_COMMITTER_NAME="$BOT_NAME" \
    GIT_COMMITTER_EMAIL="$BOT_EMAIL" \
    git commit -m "$COMMIT_MESSAGE"

    echo "Pushing changes to Codeberg..."
    # Force push to update the branch (and the linked PR if it already exists)
    git push -f "https://$TOKEN@codeberg.org/${REPO_FULL_NAME}.git" "$TEMP_BRANCH"
}

# ------------------------------------------------------------------------------
# Queries the Codeberg API to see if a Pull Request already exists from our temporary branch to the main base branch.
# 
# Arguments: None
# 
# Returns: 0 (True) if an open PR exists, 1 (False) if it does not.
# ------------------------------------------------------------------------------
has_open_pull_request() {
    local pr_search
    
    # Search for an open PR from our specific head branch to the base branch
    pr_search=$(curl -s -H "Authorization: token $TOKEN" \
        "$API_URL/pulls?state=open&head=$TEMP_BRANCH&base=$BASE_BRANCH")

    # Check if the JSON response contains our branch name in the "head" object
    if echo "$pr_search" | grep -q "\"head\":{\"label\":\"$TEMP_BRANCH\""; then
        return 0 # True
    else
        return 1 # False
    fi
}

# ------------------------------------------------------------------------------
# Constructs a JSON payload and sends it to the Codeberg API to open a brand new Pull Request.
# 
# Arguments: None
# ------------------------------------------------------------------------------
create_pull_request() {
    local pr_payload
    local create_response
    
    echo "No open PR found. Creating a new one..."
    
    pr_payload=$(cat <<EOF
{
  "base": "$BASE_BRANCH",
  "head": "$TEMP_BRANCH",
  "title": "$PR_TITLE",
  "body": "This is an automated PR generated by [release-plz](https://github.com/release-plz/release-plz) via Woodpecker CI."
}
EOF
)

    create_response=$(curl -s -X 'POST' "$API_URL/pulls" \
        -H "Authorization: token $TOKEN" \
        -H "Content-Type: application/json" \
        -d "$pr_payload")

    # Verify if creation was successful by looking for an ID in the response
    if echo "$create_response" | grep -q "\"id\":"; then
        echo "Successfully created Pull Request!"
    else
        echo "Failed to create Pull Request. Response:"
        echo "$create_response"
        exit 1
    fi
}

# ==============================================================================
# Main Execution Block
# ==============================================================================

validate_environment
run_release_plz

# If there are no changes, we can exit cleanly right away.
if ! has_changes; then
    echo "No changes detected. Repository is up to date."
    exit 0
fi

echo "Changes detected. Preparing to update Codeberg..."
commit_and_push_changes

echo "Checking for existing Pull Request..."
if has_open_pull_request; then
    echo "An open Pull Request already exists, it has been updated."
else
    create_pull_request
fi

echo "--- Release-plz plugin task completed ---"