What are GitHub Actions triggers? Explain on: push, pull_request, schedule, and workflow_dispatch.

on:
  push:
    branches:
      - main
      - develop
      - 'release/**'   # wildcard: release/1.0, release/2.0
    branches-ignore:
      - 'dependabot/**'
    paths:
      - 'src/**'       # only trigger if files in src/ changed
      - 'pom.xml'
    paths-ignore:
      - '**.md'        # ignore markdown file changes
      - 'docs/**'

on:
  pull_request:
    branches: [main, develop]   # PRs targeting these branches
    types:
      - opened        # new PR created
      - synchronize   # new commit pushed to PR
      - reopened      # PR reopened
      - ready_for_review  # draft → ready

on:
  schedule:
    - cron: '0 2 * * *'      # every day at 2:00 AM UTC
    - cron: '0 22 * * 1-5'   # weekdays at 10 PM UTC
    - cron: '0 0 * * 0'      # every Sunday at midnight

# Cron format: minute hour day-of-month month day-of-week
# H = hash in Jenkins, but GitHub Actions uses standard cron only

on:
  workflow_dispatch:
    inputs:
      environment:
        description: 'Target environment'
        required: true
        default: 'staging'
        type: choice
        options: [staging, qa, production]

      browser:
        description: 'Browser to test with'
        required: true
        default: 'chrome'
        type: choice
        options: [chrome, firefox, edge]

      run_full_suite:
        description: 'Run full regression?'
        required: false
        default: false
        type: boolean

# Access inputs in steps:
# ${{ github.event.inputs.environment }}
# ${{ inputs.environment }}  (newer syntax)

# Called by another workflow (reusable workflow)
on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
    secrets:
      deploy-key:
        required: true

on:
  push:
    branches: [main]
  pull_request:
    branches: [main, develop]
  schedule:
    - cron: '0 1 * * *'    # nightly regression
  workflow_dispatch:        # manual trigger anytime

steps:
  - name: Show trigger info
    run: |
      echo "Event: ${{ github.event_name }}"     # push / pull_request / schedule
      echo "Branch: ${{ github.ref_name }}"       # main / develop
      echo "Actor: ${{ github.actor }}"            # who triggered it
      echo "SHA: ${{ github.sha }}"               # commit hash
      echo "PR number: ${{ github.event.number }}" # only for pull_request