import json
import sys

def validate_plan(plan_path):
    try:
        with open(plan_path, 'r') as f:
            plan = json.load(f)
    except FileNotFoundError:
        print(f"Error: Plan file {plan_path} not found.")
        sys.exit(1)

    resource_changes = plan.get('resource_changes', [])
    
    # 1. Validation: Gitea Server Protection
    # Gitea server ID is 114, so expected address is proxmox_lxc.lxc["114"]
    # We also check for name just in case.
    gitea_deleted = False
    
    # 2. Validation: Runner Availability
    # We need to ensure at least one runner exists after apply.
    active_runners = 0
    
    print("Validating Plan...")

    for change in resource_changes:
        address = change.get('address', '')
        actions = change.get('change', {}).get('actions', [])
        after = change.get('change', {}).get('after', {})
        
        # Check if it is being deleted
        is_deleted = "delete" in actions and "create" not in actions # pure delete
        
        # Check for Gitea Server (ID 114)
        if 'proxmox_lxc.lxc["114"]' in address:
            if is_deleted:
                print(f"[FAIL] Plan attempts to destroy the Gitea Server ({address})!")
                gitea_deleted = True
            else:
                print(f"[PASS] Gitea Server ({address}) is safe (Actions: {actions}).")

        # Check for Gitea Runners
        # We identify runners by tag "gitea-runner" or name convention if tag isn't available in `after` (e.g. unknown).
        # However, `after` should contain tags if it's not a delete.
        # If it is a delete, we check `before`.
        
        is_runner = False
        tags = ""
        
        # Check 'after' state for surviving/new resources
        if not is_deleted and after:
            tags = after.get('tags', '')
        # Check 'before' state for deleted resources (just for logging/logic if needed)
        
        # Logic: We only care about what remains or is created.
        if not is_deleted:
             # If tags are computed/unknown, we might need to fallback to name or address
             # Runners are usually created via loop in locals, so names are predictable "gitea-runner-X"
             # Address format: proxmox_lxc.lxc["900"], proxmox_lxc.lxc["901"], etc.
             
             name = after.get('name', '') if after else ''
             
             if "gitea-runner" in tags or "gitea-runner" in name:
                 is_runner = True

             if is_runner:
                 active_runners += 1

    if gitea_deleted:
        sys.exit(1)

    print(f"Active runners after apply: {active_runners}")
    if active_runners < 1:
        print("[FAIL] Plan results in zero active Gitea Runners!")
        sys.exit(1)
    
    print("[PASS] Plan validation successful.")

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python validate_plan.py <path_to_plan.json>")
        sys.exit(1)
    
    validate_plan(sys.argv[1])