# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import json
import logging
import math
import os
from enum import Enum
from pathlib import Path
from typing import Literal, Optional

import yaml
from pydantic import BaseModel, Field, model_validator

from dynamo.planner.config.defaults import SLAPlannerDefaults

logger = logging.getLogger(__name__)


class PlannerPreDeploymentSweepMode(str, Enum):
    None_ = "none"
    Rapid = "rapid"
    Thorough = "thorough"


class PlannerConfig(BaseModel):
    """Pydantic configuration for the Dynamo Planner.

    Replaces the argparse-based CLI. All fields mirror the former CLI flags
    with defaults sourced from SLAPlannerDefaults.
    """

    pre_deployment_sweeping_mode: Optional[PlannerPreDeploymentSweepMode] = Field(
        default=PlannerPreDeploymentSweepMode.Rapid,
        description='Controls pre-deployment sweeping mode for planner in-depth profiling. "none" means no pre-deployment sweep (only load-based scaling). "rapid" uses AI Configurator to simulate engine performance. "thorough" uses real GPUs to measure engine performance (takes several hours).',
    )

    environment: Literal[
        "kubernetes", "virtual", "global-planner"
    ] = SLAPlannerDefaults.environment
    namespace: str = Field(
        default_factory=lambda: os.environ.get("DYN_NAMESPACE", "dynamo")
    )
    backend: Literal["vllm", "sglang", "trtllm", "mocker"] = SLAPlannerDefaults.backend
    mode: Literal["disagg", "prefill", "decode", "agg"] = SLAPlannerDefaults.mode
    optimization_target: Literal["throughput", "latency", "sla"] = Field(
        default="throughput",
        description=(
            "Scaling optimization target. "
            "'throughput' (default) and 'latency' use static thresholds on queue "
            "depth and KV cache utilization — no SLA targets or profiling needed. "
            "'sla' uses regression-based scaling that targets specific ttft/itl values."
        ),
    )

    no_operation: bool = SLAPlannerDefaults.no_operation
    log_dir: Optional[str] = SLAPlannerDefaults.log_dir
    throughput_adjustment_interval: int = (
        SLAPlannerDefaults.throughput_adjustment_interval
    )
    max_gpu_budget: int = SLAPlannerDefaults.max_gpu_budget
    min_endpoint: int = SLAPlannerDefaults.min_endpoint

    decode_engine_num_gpu: Optional[int] = None
    prefill_engine_num_gpu: Optional[int] = None

    profile_results_dir: str = SLAPlannerDefaults.profile_results_dir

    ttft: float = SLAPlannerDefaults.ttft
    itl: float = SLAPlannerDefaults.itl

    # Load predictor settings
    load_predictor: str = SLAPlannerDefaults.load_predictor
    load_predictor_log1p: bool = SLAPlannerDefaults.load_predictor_log1p
    prophet_window_size: int = SLAPlannerDefaults.prophet_window_size
    load_predictor_warmup_trace: Optional[str] = None

    # Kalman filter settings
    kalman_q_level: float = SLAPlannerDefaults.kalman_q_level
    kalman_q_trend: float = SLAPlannerDefaults.kalman_q_trend
    kalman_r: float = SLAPlannerDefaults.kalman_r
    kalman_min_points: int = SLAPlannerDefaults.kalman_min_points

    # Prometheus settings
    metric_pulling_prometheus_endpoint: str = Field(
        default_factory=lambda: os.environ.get(
            "PROMETHEUS_ENDPOINT",
            "http://prometheus-kube-prometheus-prometheus.monitoring.svc.cluster.local:9090",
        )
    )
    metric_reporting_prometheus_port: int = Field(
        default_factory=lambda: int(os.environ.get("PLANNER_PROMETHEUS_PORT", 0))
    )
    throughput_metrics_source: Literal[
        "frontend", "router"
    ] = SLAPlannerDefaults.throughput_metrics_source

    model_name: Optional[str] = None

    # Global planner environment
    global_planner_namespace: Optional[str] = None

    # Scaling mode flags
    enable_throughput_scaling: bool = SLAPlannerDefaults.enable_throughput_scaling
    enable_load_scaling: bool = SLAPlannerDefaults.enable_load_scaling

    # Load-based scaling settings
    load_adjustment_interval: int = Field(
        default=SLAPlannerDefaults.load_adjustment_interval,
        description=(
            "Interval in seconds for FPM regression model updates AND load-based "
            "scaling decisions. Even when only throughput-based scaling is enabled, "
            "live FPM observations are fed into the regression at this interval to "
            "keep the performance model accurate. Must be shorter than "
            "throughput_adjustment_interval."
        ),
    )
    max_num_fpm_samples: int = SLAPlannerDefaults.max_num_fpm_samples
    fpm_sample_bucket_size: int = SLAPlannerDefaults.fpm_sample_bucket_size
    load_scaling_down_sensitivity: int = (
        SLAPlannerDefaults.load_scaling_down_sensitivity
    )
    load_metric_samples: int = SLAPlannerDefaults.load_metric_samples
    load_min_observations: int = SLAPlannerDefaults.load_min_observations

    # Diagnostics report settings
    report_interval_hours: Optional[float] = Field(
        default=None,
        description=(
            "Generate an HTML diagnostics report every N hours (simulated time). "
            "Set to None to disable periodic report generation."
        ),
    )
    report_output_dir: str = Field(
        default="./planner_reports",
        description="Directory for HTML diagnostics reports.",
    )

    @model_validator(mode="after")
    def _validate_config(self) -> "PlannerConfig":
        if self.report_interval_hours is not None:
            if (
                not math.isfinite(self.report_interval_hours)
                or self.report_interval_hours <= 0
            ):
                raise ValueError(
                    "report_interval_hours must be a positive finite number or None"
                )

        sqrt = math.isqrt(self.fpm_sample_bucket_size)
        if sqrt * sqrt != self.fpm_sample_bucket_size:
            raise ValueError(
                f"fpm_sample_bucket_size must be a perfect square, "
                f"got {self.fpm_sample_bucket_size}"
            )

        if self.environment == "global-planner" and not self.global_planner_namespace:
            raise ValueError(
                "global_planner_namespace is required when environment='global-planner'. "
                "Please specify the namespace where GlobalPlanner is running."
            )

        # Easy mode: force load scaling on, throughput scaling off
        if self.optimization_target != "sla":
            self.enable_load_scaling = True
            self.enable_throughput_scaling = False
            if (
                self.ttft != SLAPlannerDefaults.ttft
                or self.itl != SLAPlannerDefaults.itl
            ):
                logger.warning(
                    "optimization_target=%s ignores ttft/itl values; "
                    "set optimization_target='sla' to use SLA-based scaling",
                    self.optimization_target,
                )

        # At least one scaling mode must be enabled
        if not self.enable_throughput_scaling and not self.enable_load_scaling:
            raise ValueError(
                "At least one scaling mode must be enabled "
                "(enable_throughput_scaling or enable_load_scaling)"
            )

        if self.enable_throughput_scaling:
            if (
                self.pre_deployment_sweeping_mode is None
                or self.pre_deployment_sweeping_mode
                == PlannerPreDeploymentSweepMode.None_
            ):
                raise ValueError(
                    "pre_deployment_sweeping_mode cannot be 'none' when "
                    "enable_throughput_scaling is True. Throughput-based scaling "
                    "requires pre-deployment sweeping to profile engine performance."
                )

        if self.enable_load_scaling:
            if self.enable_throughput_scaling:
                if self.load_adjustment_interval >= self.throughput_adjustment_interval:
                    raise ValueError(
                        f"load_adjustment_interval ({self.load_adjustment_interval}s) "
                        f"must be shorter than throughput_adjustment_interval ({self.throughput_adjustment_interval}s). "
                        "Load-based scaling is the fast reactive loop; throughput-based is the "
                        "slow predictive loop."
                    )

        return self

    @classmethod
    def from_config_arg(cls, config_arg: str) -> "PlannerConfig":
        """Create a PlannerConfig from a CLI --config argument.

        Auto-detects whether the argument is a file path (JSON/YAML) or an
        inline JSON string, loads it, and validates.
        """
        path = Path(config_arg)
        try:
            is_file = path.is_file()
        except OSError:
            # Path component too long (e.g. inline JSON string passed as config arg)
            is_file = False
        if is_file:
            return cls._load_from_file(path)

        # Try parsing as inline JSON
        try:
            data = json.loads(config_arg)
        except json.JSONDecodeError as e:
            raise ValueError(
                f"--config value is neither a valid file path nor valid JSON: {e}"
            ) from e

        return cls.model_validate(data)

    @classmethod
    def _load_from_file(cls, path: Path) -> "PlannerConfig":
        suffix = path.suffix.lower()
        text = path.read_text()

        if suffix in (".yaml", ".yml"):
            data = yaml.safe_load(text)
        elif suffix == ".json":
            data = json.loads(text)
        else:
            # Try JSON first, then YAML
            try:
                data = json.loads(text)
            except json.JSONDecodeError:
                try:
                    data = yaml.safe_load(text)
                except ImportError:
                    raise ValueError(
                        f"Could not parse config file '{path}'. "
                        "For YAML support, install pyyaml."
                    )

        return cls.model_validate(data)

    def scaling_enabled(self) -> bool:
        return self.enable_throughput_scaling or self.enable_load_scaling


if __name__ == "__main__":
    from pathlib import Path

    schema = PlannerConfig.model_json_schema()

    output_path = Path(__file__).parent / "planner_config_json_schema.json"
    output_path.write_text(json.dumps(schema, indent=2))
    print(f"PlannerConfig JSON schema written to {output_path}")
