import yaml
import sys
import copy

def default_deploy():
    return {
        "mode": "replicated",
        "replicas": 1,
        "restart_policy": {"condition": "any"},
        "labels": {},
        "placement": {
            "constraints": [
                "node.role == manager"
            ]
        }
    }


def convert_service(service):
    swarm_service = {}

    # Create a fresh deploy section each time (avoids YAML anchors)
    deploy_section = default_deploy()

    for key, value in service.items():

        # Unsupported in Swarm
        if key in ["container_name", "restart", "depends_on"]:
            continue

        # Move labels → deploy.labels
        if key == "labels":
            if isinstance(value, dict):
                deploy_section["labels"].update(value)
            elif isinstance(value, list):
                for item in value:
                    if "=" in item:
                        k, v = item.split("=", 1)
                        deploy_section["labels"][k] = v
            continue

        swarm_service[key] = value

    # Merge user deploy section if present
    if "deploy" in service:
        user_deploy = service["deploy"]

        # merge deploy.labels
        if "labels" in user_deploy:
            labels = user_deploy["labels"]
            if isinstance(labels, dict):
                deploy_section["labels"].update(labels)
            elif isinstance(labels, list):
                for item in labels:
                    if "=" in item:
                        k, v = item.split("=", 1)
                        deploy_section["labels"][k] = v

        # merge placement constraints
        if "placement" in user_deploy:
            if "constraints" in user_deploy["placement"]:
                deploy_section["placement"]["constraints"].extend(
                    user_deploy["placement"]["constraints"]
                )

        # merge other keys
        for dk, dv in user_deploy.items():
            if dk not in ["labels", "placement"]:
                deploy_section[dk] = copy.deepcopy(dv)

    swarm_service["deploy"] = deploy_section
    return swarm_service


def convert_compose_to_swarm(app):
    output_file = "__swarm/" + app + "/" + app + "-swarm.yml"
    input_file = app + "/docker-compose.yml"
    with open(input_file, "r") as f:
        compose = yaml.safe_load(f)

    swarm = {"version": "3.9", "services": {}}

    for name, service in compose.get("services", {}).items():
        swarm["services"][name] = convert_service(service)

    for section in ["networks", "volumes", "configs", "secrets"]:
        if section in compose:
            swarm[section] = compose[section]

    # Prevent PyYAML from creating anchors
    class NoAliasDumper(yaml.SafeDumper):
        def ignore_aliases(self, data):
            return True

    with open(output_file, "w") as f:
        yaml.dump(swarm, f, sort_keys=False, Dumper=NoAliasDumper)

    print(f"✔ Swarm file written to: {output_file}")


if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python convert_to_swarm.py app_name")
        sys.exit(1)

    convert_compose_to_swarm(sys.argv[1])