from __future__ import annotations

import os
from dataclasses import dataclass
from typing import Any, Protocol

from src.aws import mlflow as aws_mlflow
from src.config import Config, MlflowMode


class Tracker(Protocol):
    def start_training_run(self, training_job: Any, *, region: str, profile: str, role_arn: str) -> str | None: ...

    def finalize_training_run(
        self,
        *,
        run_id: str | None,
        training_job_status: Any,
    ) -> str | None: ...


@dataclass(frozen=True)
class NoopTracker:
    def start_training_run(self, training_job: Any, *, region: str, profile: str, role_arn: str) -> str | None:
        return None

    def finalize_training_run(self, *, run_id: str | None, training_job_status: Any) -> str | None:
        return None


@dataclass(frozen=True)
class MlflowTracker:
    mlflow: Any
    tracking_uri: str
    experiment_name: str
    registered_model_name: str
    register_trained_models: bool

    @classmethod
    def from_config(cls, cfg: Config) -> Tracker:
        if cfg.mlflow.mode is MlflowMode.disabled:
            return NoopTracker()

        os.environ.setdefault("MLFLOW_SUPPRESS_PRINTING_URL_TO_STDOUT", "true")

        try:
            import mlflow
        except ImportError as e:
            raise RuntimeError(
                "MLflow is enabled in config but optional dependencies are not installed. "
                "Install with: qc-cli[mlflow]"
            ) from e

        tracking_server_name = cfg.effective_mlflow_tracking_server_name
        if not tracking_server_name:
            raise RuntimeError("MLflow tracking server name could not be resolved.")

        tracking_uri = aws_mlflow.get_tracking_server_arn(
            cfg.aws.region,
            cfg.aws.profile,
            tracking_server_name,
        )
        mlflow.set_tracking_uri(tracking_uri)
        mlflow.set_experiment(cfg.mlflow.experiment_name)

        return cls(
            mlflow=mlflow,
            tracking_uri=tracking_uri,
            experiment_name=cfg.mlflow.experiment_name,
            registered_model_name=cfg.mlflow.registered_model_name,
            register_trained_models=cfg.mlflow.register_trained_models,
        )

    def start_training_run(self, training_job: Any, *, region: str, profile: str, role_arn: str) -> str | None:
        run = self.mlflow.start_run(run_name=training_job.job_name)
        run_id = str(run.info.run_id)

        params = {
            "aws.region": region,
            "aws.profile": profile,
            "sagemaker.role_arn": role_arn,
            "sagemaker.job_name": training_job.job_name,
            "sagemaker.training_image": training_job.image_uri,
            "sagemaker.instance_type": training_job.instance_type,
            "sagemaker.instance_count": training_job.instance_count,
            "sagemaker.s3_train_uri": training_job.s3_train_uri,
            "sagemaker.s3_output_path": training_job.s3_output_path,
            "sagemaker.entry_point": training_job.entry_point,
            "sagemaker.source_dir": training_job.source_dir,
        }
        self._log_params(params)
        self._log_params({f"hyperparameters.{key}": value for key, value in training_job.hyperparameters.items()})
        self.mlflow.set_tags(
            {
                "qc_cli.stage": "prerelease",
                "qc_cli.command": "train start",
                "sagemaker.job_name": training_job.job_name,
            }
        )
        self.mlflow.end_run()
        return run_id

    def finalize_training_run(self, *, run_id: str | None, training_job_status: Any) -> str | None:
        if not run_id:
            return None

        with self.mlflow.start_run(run_id=run_id):
            self._log_params(
                {
                    "sagemaker.training_status": training_job_status.status,
                    "sagemaker.created_at": training_job_status.created,
                    "sagemaker.modified_at": training_job_status.modified,
                    "sagemaker.model_artifacts": training_job_status.model_artifacts,
                    "sagemaker.failure_reason": training_job_status.failure_reason,
                }
            )
            self._log_final_metrics(training_job_status.raw)
            self.mlflow.set_tag("qc_cli.command", "train status")

            if training_job_status.status != "Completed" or not training_job_status.model_artifacts:
                self.mlflow.set_tag("qc_cli.training_terminal_status", training_job_status.status)
                return None

            if not self.register_trained_models:
                return None

            client = self.mlflow.tracking.MlflowClient()
            self._ensure_registered_model(client, self.registered_model_name)
            version = client.create_model_version(
                name=self.registered_model_name,
                source=training_job_status.model_artifacts,
                run_id=run_id,
                tags={
                    "qc_cli.stage": "prerelease",
                    "sagemaker.job_name": training_job_status.name,
                },
            )
            version_number = str(version.version)
            self._set_alias(client, self.registered_model_name, "prerelease-latest", version_number)
            self.mlflow.set_tag("qc_cli.registered_model_name", self.registered_model_name)
            self.mlflow.set_tag("qc_cli.registered_model_version", version_number)
            return version_number

    def _log_params(self, params: dict[str, Any]) -> None:
        cleaned = {key: str(value) for key, value in params.items() if value is not None}
        if cleaned:
            self.mlflow.log_params(cleaned)

    def _log_final_metrics(self, training_job: dict[str, Any]) -> None:
        metrics = {}
        for metric in training_job.get("FinalMetricDataList", []):
            name = metric.get("MetricName")
            value = metric.get("Value")
            if name and value is not None:
                metrics[str(name)] = float(value)
        if metrics:
            self.mlflow.log_metrics(metrics)

    def _ensure_registered_model(self, client: Any, name: str) -> None:
        try:
            client.get_registered_model(name)
        except Exception:
            client.create_registered_model(name)

    def _set_alias(self, client: Any, name: str, alias: str, version: str) -> None:
        if hasattr(client, "set_registered_model_alias"):
            client.set_registered_model_alias(name, alias, version)