pipeline {
    agent any

    environment {
        PYTHON_VERSION = '3.11'
        NODE_VERSION = '18'
        SUT_URL = 'http://localhost'
    }

    options {
        timeout(time: 30, unit: 'MINUTES')
        buildDiscarder(logRotator(numToKeepStr: '10'))
        disableConcurrentBuilds()
    }

    stages {
        stage('Checkout') {
            steps {
                echo 'One does not simply skip the checkout stage...'
                checkout scm
            }
        }

        stage('Setup Environment') {
            steps {
                echo 'Preparing the Fellowship environment...'
                sh '''
                    # Create a Python virtual environment (PEP 668 compliant)
                    python3 -m venv venv
                    . venv/bin/activate
                    python3 -m pip install --upgrade pip setuptools wheel
                    echo "✓ Virtual environment ready"
                '''
            }
        }

        stage('Install Dependencies') {
            parallel {
                stage('Backend Deps') {
                    steps {
                        echo 'Installing backend dependencies for the Fellowship...'
                        sh '''
                            . venv/bin/activate
                            pip install -r sut/backend/requirements.txt
                            pip install -r tests/requirements.txt
                        '''
                    }
                }
                stage('Frontend Deps') {
                    steps {
                        echo 'Installing frontend dependencies...'
                        sh '''
                            cd sut/frontend
                            npm ci --prefer-offline || npm install
                        '''
                    }
                }
            }
        }

        stage('Lint') {
            steps {
                echo 'The Eye of Sauron watches for code style violations...'
                sh '''
                    . venv/bin/activate
                    pip install flake8 --quiet
                    # E9/F63/F7/F82 = syntax & fatal errors — these must fail the build.
                    # Warnings (E1xx, W) are informational only for this tutorial pipeline.
                    flake8 sut/backend tests/*.py \
                        --count --select=E9,F63,F7,F82 \
                        --show-source --statistics
                '''
            }
        }

        stage('Unit Tests') {
            steps {
                echo 'Running unit tests across the Fellowship...'
                sh '''
                    . venv/bin/activate
                    mkdir -p reports
                    PYTHONPATH=sut/backend python -m pytest \
                        tests/backend/services/test_bargaining_algorithm.py \
                        tests/backend/services/test_bargaining_config.py \
                        tests/backend/services/test_shop_service.py \
                        tests/backend/services/test_negotiation_logger.py \
                        -v --tb=short \
                        --junitxml=reports/unit-tests.xml \
                        --no-header \
                        --override-ini="addopts=--strict-markers --tb=short -v"
                '''
            }
            post {
                always {
                    junit allowEmptyResults: true, testResults: 'reports/unit-tests.xml'
                }
            }
        }

        stage('Build Frontend') {
            steps {
                echo 'Forging the frontend in the fires of Mount Doom...'
                sh '''
                    cd sut/frontend
                    npm run build
                '''
            }
        }

        stage('Integration Tests') {
            steps {
                echo 'The quest continues — running integration tests...'
                sh '''
                    . venv/bin/activate
                    mkdir -p reports
                    PYTHONPATH=sut/backend python -m pytest \
                        tests/backend/services/test_bargaining_algorithm.py \
                        tests/backend/services/test_bargaining_config.py \
                        tests/backend/services/test_shop_service.py \
                        tests/backend/services/test_negotiation_logger.py \
                        -v --tb=short \
                        --junitxml=reports/integration-tests.xml \
                        --no-header \
                        --override-ini="addopts=--strict-markers --tb=short -v" \
                        -m "not realstack"
                '''
            }
            post {
                always {
                    junit allowEmptyResults: true, testResults: 'reports/integration-tests.xml'
                }
            }
        }

        stage('Deploy') {
            when {
                branch 'main'
            }
            steps {
                echo 'Deploying the Fellowship SUT to the land of Docker...'
                sh '''
                    cp caddy/Caddyfile.local caddy/Caddyfile
                    docker compose down --remove-orphans || true
                    docker compose up -d --build
                '''
            }
        }
    }

    post {
        always {
            echo 'The journey is complete — collecting artifacts...'
            archiveArtifacts artifacts: 'reports/**/*.xml', allowEmptyArchive: true
        }
        success {
            echo 'The Fellowship has succeeded! The quest is complete.'
        }
        failure {
            echo 'The Fellowship has failed! Sauron grows stronger...'
            mail to: 'fellowship@middle-earth.local',
                 subject: "Build Failed: ${env.JOB_NAME} [${env.BUILD_NUMBER}]",
                 body: "The Ring has been lost. Build ${env.BUILD_URL} has failed."
        }
        unstable {
            echo 'The quest is unstable — some tests did not pass.'
        }
    }
}