#!/usr/bin/env python3
"""
Gitea CI/CD Webhook Controller
Listens for push events from all Gitea repos and triggers automated build & deploy.
"""

import json
import os
import subprocess
import hmac
import hashlib
import logging
import time
import threading
from http.server import HTTPServer, BaseHTTPRequestHandler

logging.basicConfig(level=logging.INFO, format='%(asctime)s %(levelname)s %(message)s')
logger = logging.getLogger('ci-controller')

# Configuration from environment
GITEA_URL = os.environ.get('GITEA_URL', 'http://gitea-http.gitea.svc:3000')
GITEA_USER = os.environ.get('GITEA_USER', 'gitea_admin')
GITEA_PASSWORD = os.environ.get('GITEA_PASSWORD', '')
REGISTRY = os.environ.get('REGISTRY', '10.0.0.3:31427')
GITOPS_REPO = os.environ.get('GITOPS_REPO', f'{GITEA_URL}/{GITEA_USER}/gitops-infra.git')
WEBHOOK_SECRET = os.environ.get('WEBHOOK_SECRET', '')
BUILD_NAMESPACE = os.environ.get('BUILD_NAMESPACE', 'build')
REGISTRY_SECRET = os.environ.get('REGISTRY_SECRET', 'gitea-registry')
IGNORED_REPOS = set(os.environ.get('IGNORED_REPOS', 'gitops-infra').split(','))


def verify_signature(payload, signature):
    """Verify Gitea webhook signature."""
    if not WEBHOOK_SECRET:
        return True
    expected = hmac.HMAC(WEBHOOK_SECRET.encode(), payload, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, signature)


def repo_has_dockerfile(owner, repo):
    """Check if repo has a Dockerfile via Gitea API."""
    try:
        result = subprocess.run(
            ['curl', '-sf', '-u', f'{GITEA_USER}:{GITEA_PASSWORD}',
             f'{GITEA_URL}/api/v1/repos/{owner}/{repo}/contents/Dockerfile'],
            capture_output=True, text=True, timeout=10
        )
        return result.returncode == 0
    except Exception as e:
        logger.error(f'Error checking Dockerfile: {e}')
        return False


def gitops_app_exists(repo_name):
    """Check if gitops environment exists for this repo."""
    kustomization = f'environments/{repo_name}/overlays/production/kustomization.yaml'
    try:
        result = subprocess.run(
            ['curl', '-sf', '-u', f'{GITEA_USER}:{GITEA_PASSWORD}',
             f'{GITEA_URL}/api/v1/repos/{GITEA_USER}/gitops-infra/contents/{kustomization}'],
            capture_output=True, text=True, timeout=10
        )
        return result.returncode == 0
    except Exception:
        return False


def create_kaniko_pod(owner, repo, short_sha):
    """Create a Kaniko build pod."""
    pod_name = f'kaniko-{repo}'
    clone_url = f'{GITEA_URL}/{owner}/{repo}.git'
    clone_url_auth = f'http://{GITEA_USER}:{GITEA_PASSWORD}@gitea-http.gitea.svc:3000/{owner}/{repo}.git'
    image_dest = f'{REGISTRY}/{owner}/{repo}'

    # Delete existing pod if any
    subprocess.run(
        ['kubectl', 'delete', 'pod', pod_name, '-n', BUILD_NAMESPACE, '--ignore-not-found=true'],
        capture_output=True, timeout=30
    )
    time.sleep(2)

    manifest = f"""
apiVersion: v1
kind: Pod
metadata:
  name: {pod_name}
  namespace: {BUILD_NAMESPACE}
  labels:
    app: kaniko-build
    repo: {repo}
    commit: "{short_sha}"
spec:
  restartPolicy: Never
  tolerations:
  - key: node-role.kubernetes.io/control-plane
    effect: NoSchedule
  initContainers:
  - name: git-clone
    image: alpine/git:latest
    command: ["sh", "-c"]
    args:
    - git clone {clone_url_auth} /workspace
    volumeMounts:
    - name: workspace
      mountPath: /workspace
  containers:
  - name: kaniko
    image: gcr.io/kaniko-project/executor:latest
    args:
    - --dockerfile=Dockerfile
    - --context=/workspace
    - "--destination={image_dest}:{short_sha}"
    - "--destination={image_dest}:latest"
    - --insecure
    - --insecure-pull
    - --skip-tls-verify
    - --skip-tls-verify-pull
    - "--insecure-registry={REGISTRY}"
    - --snapshot-mode=redo
    - --use-new-run
    - --compressed-caching=false
    resources:
      requests:
        cpu: 500m
        memory: 1Gi
      limits:
        cpu: "2"
        memory: 3Gi
    volumeMounts:
    - name: workspace
      mountPath: /workspace
    - name: docker-config
      mountPath: /kaniko/.docker
  volumes:
  - name: workspace
    emptyDir: {{}}
  - name: docker-config
    secret:
      secretName: {REGISTRY_SECRET}
      items:
      - key: .dockerconfigjson
        path: config.json
"""

    result = subprocess.run(
        ['kubectl', 'apply', '-f', '-'],
        input=manifest, capture_output=True, text=True, timeout=30
    )

    if result.returncode != 0:
        logger.error(f'Failed to create Kaniko pod: {result.stderr}')
        return False

    logger.info(f'Kaniko pod {pod_name} created for {owner}/{repo}:{short_sha}')
    return True


def wait_for_build(repo, timeout=900):
    """Wait for Kaniko build to complete."""
    pod_name = f'kaniko-{repo}'
    deadline = time.time() + timeout

    while time.time() < deadline:
        result = subprocess.run(
            ['kubectl', 'get', 'pod', pod_name, '-n', BUILD_NAMESPACE,
             '-o', 'jsonpath={.status.phase}'],
            capture_output=True, text=True, timeout=10
        )
        phase = result.stdout.strip()

        if phase == 'Succeeded':
            logger.info(f'Build succeeded for {repo}')
            return True
        elif phase == 'Failed':
            logger.error(f'Build failed for {repo}')
            logs = subprocess.run(
                ['kubectl', 'logs', pod_name, '-n', BUILD_NAMESPACE, '--tail=20'],
                capture_output=True, text=True, timeout=10
            )
            logger.error(f'Build logs: {logs.stdout}')
            return False

        time.sleep(15)

    logger.error(f'Build timed out for {repo}')
    return False


def update_gitops(owner, repo, short_sha):
    """Update gitops-infra with new image tag."""
    import tempfile
    gitops_dir = tempfile.mkdtemp()
    gitops_url_auth = f'http://{GITEA_USER}:{GITEA_PASSWORD}@gitea-http.gitea.svc:3000/{GITEA_USER}/gitops-infra.git'

    try:
        # Clone gitops repo
        subprocess.run(['git', 'clone', gitops_url_auth, gitops_dir],
                       capture_output=True, timeout=30, check=True)

        kustomization = os.path.join(gitops_dir,
            f'environments/{repo}/overlays/production/kustomization.yaml')

        if not os.path.exists(kustomization):
            logger.warning(f'No gitops environment for {repo}, skipping update')
            return False

        # Update image tag
        subprocess.run(
            ['sed', '-i', f's/newTag: ".*"/newTag: "{short_sha}"/', kustomization],
            check=True, timeout=10
        )

        # Commit and push
        subprocess.run(['git', 'config', 'user.name', 'CI Controller'],
                       cwd=gitops_dir, check=True, timeout=5)
        subprocess.run(['git', 'config', 'user.email', 'ci@gitea.local'],
                       cwd=gitops_dir, check=True, timeout=5)
        subprocess.run(['git', 'add', '.'], cwd=gitops_dir, check=True, timeout=5)

        # Check if there are changes
        diff = subprocess.run(['git', 'diff', '--cached', '--quiet'],
                              cwd=gitops_dir, capture_output=True)
        if diff.returncode == 0:
            logger.info(f'No changes for {repo}, already at {short_sha}')
            return True

        subprocess.run(['git', 'commit', '-m', f'Deploy {repo} {short_sha}'],
                       cwd=gitops_dir, check=True, timeout=10)
        subprocess.run(['git', 'push'], cwd=gitops_dir, check=True, timeout=30)

        logger.info(f'GitOps updated: {repo} -> {short_sha}')
        return True

    except subprocess.CalledProcessError as e:
        logger.error(f'GitOps update failed: {e}')
        return False
    finally:
        subprocess.run(['rm', '-rf', gitops_dir], capture_output=True)


def scaffold_gitops(owner, repo):
    """Create gitops scaffolding for a new project."""
    import tempfile
    gitops_dir = tempfile.mkdtemp()
    gitops_url_auth = f'http://{GITEA_USER}:{GITEA_PASSWORD}@gitea-http.gitea.svc:3000/{GITEA_USER}/gitops-infra.git'

    try:
        subprocess.run(['git', 'clone', gitops_url_auth, gitops_dir],
                       capture_output=True, timeout=30, check=True)

        env_base = os.path.join(gitops_dir, f'environments/{repo}/base')
        env_prod = os.path.join(gitops_dir, f'environments/{repo}/overlays/production')
        apps_dir = os.path.join(gitops_dir, 'apps')
        os.makedirs(env_base, exist_ok=True)
        os.makedirs(env_prod, exist_ok=True)

        image = f'{REGISTRY}/{owner}/{repo}'

        # Base kustomization
        with open(os.path.join(env_base, 'kustomization.yaml'), 'w') as f:
            f.write(f"""apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

namespace: {repo}

resources:
  - deployment.yaml
  - service.yaml

commonLabels:
  app.kubernetes.io/managed-by: argocd
""")

        # Deployment
        with open(os.path.join(env_base, 'deployment.yaml'), 'w') as f:
            f.write(f"""apiVersion: apps/v1
kind: Deployment
metadata:
  name: {repo}
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: {repo}
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  template:
    metadata:
      labels:
        app.kubernetes.io/name: {repo}
    spec:
      automountServiceAccountToken: false
      imagePullSecrets:
        - name: gitea-registry
      containers:
        - name: {repo}
          image: {image}:latest
          ports:
            - name: http
              containerPort: 3000
              protocol: TCP
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 512Mi
          startupProbe:
            httpGet:
              path: /
              port: http
            initialDelaySeconds: 10
            periodSeconds: 5
            failureThreshold: 30
          livenessProbe:
            httpGet:
              path: /
              port: http
            periodSeconds: 30
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /
              port: http
            periodSeconds: 10
            failureThreshold: 2
""")

        # Service
        with open(os.path.join(env_base, 'service.yaml'), 'w') as f:
            f.write(f"""apiVersion: v1
kind: Service
metadata:
  name: {repo}
spec:
  type: ClusterIP
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app.kubernetes.io/name: {repo}
""")

        # Production overlay
        with open(os.path.join(env_prod, 'kustomization.yaml'), 'w') as f:
            f.write(f"""apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - ../../base

images:
  - name: {image}
    newTag: "latest"
""")

        # ArgoCD Application
        with open(os.path.join(apps_dir, f'{repo}.yaml'), 'w') as f:
            f.write(f"""apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: {repo}
  namespace: argocd
spec:
  project: infinicaretech
  source:
    repoURL: http://gitea-http.gitea.svc:3000/{GITEA_USER}/gitops-infra.git
    targetRevision: main
    path: environments/{repo}/overlays/production
  destination:
    server: https://kubernetes.default.svc
    namespace: {repo}
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true
      - PrunePropagationPolicy=foreground
      - PruneLast=true
    retry:
      limit: 3
      backoff:
        duration: 5s
        factor: 2
        maxDuration: 3m
""")

        # Commit and push
        subprocess.run(['git', 'config', 'user.name', 'CI Controller'],
                       cwd=gitops_dir, check=True, timeout=5)
        subprocess.run(['git', 'config', 'user.email', 'ci@gitea.local'],
                       cwd=gitops_dir, check=True, timeout=5)
        subprocess.run(['git', 'add', '.'], cwd=gitops_dir, check=True, timeout=5)
        subprocess.run(['git', 'commit', '-m',
                       f'Scaffold gitops for new project: {repo}'],
                       cwd=gitops_dir, check=True, timeout=10)
        subprocess.run(['git', 'push'], cwd=gitops_dir, check=True, timeout=30)

        logger.info(f'GitOps scaffolding created for {repo}')
        return True

    except subprocess.CalledProcessError as e:
        logger.error(f'Scaffold failed: {e}')
        return False
    finally:
        subprocess.run(['rm', '-rf', gitops_dir], capture_output=True)


def handle_push(payload):
    """Handle a push event."""
    repo_name = payload['repository']['name']
    owner = payload['repository']['owner']['login']
    ref = payload.get('ref', '')
    after = payload.get('after', '')

    # Only build on push to main/master
    if ref not in ('refs/heads/main', 'refs/heads/master'):
        logger.info(f'Ignoring push to {ref} for {owner}/{repo_name}')
        return

    # Skip ignored repos
    if repo_name in IGNORED_REPOS:
        logger.info(f'Ignoring push to {repo_name} (in ignore list)')
        return

    # Skip empty commits (branch delete)
    if after == '0' * 40:
        logger.info(f'Ignoring branch delete for {owner}/{repo_name}')
        return

    short_sha = after[:7]
    logger.info(f'Processing push: {owner}/{repo_name}@{short_sha}')

    # Check if repo has a Dockerfile
    if not repo_has_dockerfile(owner, repo_name):
        logger.info(f'{owner}/{repo_name} has no Dockerfile, skipping')
        return

    # Check if gitops environment exists, if not scaffold it
    if not gitops_app_exists(repo_name):
        logger.info(f'No gitops environment for {repo_name}, creating scaffold...')
        if not scaffold_gitops(owner, repo_name):
            return

    # Build with Kaniko
    if not create_kaniko_pod(owner, repo_name, short_sha):
        return

    # Wait for build
    if not wait_for_build(repo_name):
        return

    # Update gitops
    update_gitops(owner, repo_name, short_sha)


class WebhookHandler(BaseHTTPRequestHandler):
    def do_POST(self):
        content_length = int(self.headers.get('Content-Length', 0))
        body = self.rfile.read(content_length)

        # Verify signature
        signature = self.headers.get('X-Gitea-Signature', '')
        if WEBHOOK_SECRET and not verify_signature(body, signature):
            self.send_response(403)
            self.end_headers()
            self.wfile.write(b'Invalid signature')
            return

        event = self.headers.get('X-Gitea-Event', '')

        if event != 'push':
            self.send_response(200)
            self.end_headers()
            self.wfile.write(b'OK - ignored event')
            return

        try:
            payload = json.loads(body)
            self.send_response(202)
            self.end_headers()
            self.wfile.write(b'Accepted')

            # Process in background thread to not block webhook response
            t = threading.Thread(target=handle_push, args=(payload,), daemon=True)
            t.start()

        except Exception as e:
            logger.error(f'Error processing webhook: {e}')
            self.send_response(500)
            self.end_headers()
            self.wfile.write(str(e).encode())

    def do_GET(self):
        """Health check endpoint."""
        self.send_response(200)
        self.end_headers()
        self.wfile.write(b'CI Controller OK')

    def log_message(self, format, *args):
        logger.info(f'{self.client_address[0]} - {format % args}')


def setup_gitea_webhook():
    """Create a system-level webhook in Gitea for all repos."""
    import urllib.request
    import urllib.error

    webhook_url = 'http://ci-controller.build.svc:8080/webhook'
    api_url = f'{GITEA_URL}/api/v1/user/hooks'

    # Check existing webhooks
    try:
        req = urllib.request.Request(api_url)
        credentials = f'{GITEA_USER}:{GITEA_PASSWORD}'
        import base64
        auth = base64.b64encode(credentials.encode()).decode()
        req.add_header('Authorization', f'Basic {auth}')
        resp = urllib.request.urlopen(req, timeout=10)
        hooks = json.loads(resp.read())

        for hook in hooks:
            if hook.get('config', {}).get('url') == webhook_url:
                logger.info('Webhook already exists')
                return True
    except Exception as e:
        logger.warning(f'Could not check existing webhooks: {e}')

    # Create webhook
    hook_data = json.dumps({
        'type': 'gitea',
        'config': {
            'url': webhook_url,
            'content_type': 'json',
            'secret': WEBHOOK_SECRET,
        },
        'events': ['push'],
        'active': True,
    }).encode()

    try:
        req = urllib.request.Request(api_url, data=hook_data, method='POST')
        credentials = f'{GITEA_USER}:{GITEA_PASSWORD}'
        import base64
        auth = base64.b64encode(credentials.encode()).decode()
        req.add_header('Authorization', f'Basic {auth}')
        req.add_header('Content-Type', 'application/json')
        resp = urllib.request.urlopen(req, timeout=10)
        logger.info(f'Webhook created: {resp.status}')
        return True
    except urllib.error.HTTPError as e:
        logger.error(f'Failed to create webhook: {e.code} {e.read().decode()}')
        return False


if __name__ == '__main__':
    port = int(os.environ.get('PORT', '8080'))

    # Register webhook on startup
    logger.info('Setting up Gitea webhook...')
    setup_gitea_webhook()

    logger.info(f'Starting CI Controller on port {port}')
    server = HTTPServer(('0.0.0.0', port), WebhookHandler)
    server.serve_forever()