from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
sys.path.append(str(ROOT))

import joblib
import matplotlib.pyplot as plt
import numpy as np
import torch

from src.common.config import Config
from src.common.experiment_paths import (
    config_for_stage,
    model_checkpoint_for_tag,
    normalize_tag,
    processed_path_for_tag,
)
from src.data.curve_processing import clean_curve_for_dataset, is_valid_curve, resample_curve_to_features
from src.data.param_features import param_feature_transform_from_meta, transform_param_features
from src.data.params import Params, Schedule
from src.data.runner_client import CppRunner, read_result_bin
from src.data.schedule_features import build_schedule_model_vector
from src.evaluation.autofit_objective import dual_log_objective
from src.models.forward_surrogate import ForwardSurrogate


DEFAULT_SINGLE_CASE = {
    "config": "configs/data_gen_family_random.yaml",
    "tag": "family_random_50k",
    "no_schedule": False,
    "well_index": 0,
    "params": {
        "k": 0.025,
        "skin": 0.0,
        "wellboreC": 0.01,
        "phi": 0.0245,
        "h": 9.144,
        "Cf": 0.0004315,
    },
}


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Compare solver output and surrogate prediction on a single parameter set"
    )
    parser.add_argument("--config", type=str, default=DEFAULT_SINGLE_CASE["config"], help="Config yaml path")
    parser.add_argument(
        "--stage",
        choices=["fixed_case", "case_neighborhood", "family_random", "family_random_v2_q"],
        default=None,
        help="Optional stage to infer config path",
    )
    parser.add_argument("--processed", type=str, default=None, help="Processed dataset path")
    parser.add_argument("--model", type=str, default=None, help="Surrogate checkpoint path")
    parser.add_argument("--output-dir", type=str, default=None, help="Output directory")
    parser.add_argument(
        "--tag",
        type=str,
        default=DEFAULT_SINGLE_CASE["tag"],
        help="Experiment tag for processed/model lookup",
    )
    parser.add_argument(
        "--no-schedule",
        action="store_true",
        help="When --model is omitted, infer the no-schedule checkpoint path",
    )

    parser.add_argument("--k", type=float, default=DEFAULT_SINGLE_CASE["params"]["k"])
    parser.add_argument("--skin", type=float, default=DEFAULT_SINGLE_CASE["params"]["skin"])
    parser.add_argument("--wellboreC", type=float, default=DEFAULT_SINGLE_CASE["params"]["wellboreC"])
    parser.add_argument("--phi", type=float, default=DEFAULT_SINGLE_CASE["params"]["phi"])
    parser.add_argument("--h", type=float, default=DEFAULT_SINGLE_CASE["params"]["h"])
    parser.add_argument("--Cf", type=float, default=DEFAULT_SINGLE_CASE["params"]["Cf"])
    parser.add_argument(
        "--well-index",
        type=int,
        default=DEFAULT_SINGLE_CASE["well_index"],
        help="Well index for solver output",
    )
    parser.add_argument(
        "--timeQ",
        type=str,
        default=None,
        help="Override schedule durations, e.g. '1000,1000,1000' or '0,1000,1000,1000'.",
    )
    parser.add_argument(
        "--q",
        type=str,
        default=None,
        help="Override schedule rates, e.g. '200,100,0' or '0,200,100,0'.",
    )
    parser.add_argument(
        "--section-index",
        type=int,
        default=None,
        help="Override tested section index. Defaults to the last section of the overridden schedule.",
    )
    return parser.parse_args()


def calc_metrics(
    y_true: np.ndarray,
    y_pred: np.ndarray,
    eps_range: float = 1e-3,
    eps_var: float = 1e-6,
) -> dict:
    err = y_pred - y_true
    mse = np.mean(err**2)
    rmse = float(np.sqrt(mse))
    mae = float(np.mean(np.abs(err)))
    bias = float(np.mean(err))

    value_range = float(np.max(y_true) - np.min(y_true))
    ss_tot = float(np.sum((y_true - np.mean(y_true)) ** 2))
    ss_res = float(np.sum(err**2))

    valid_nrmse = value_range > eps_range
    valid_r2 = ss_tot > eps_var

    nrmse = float(rmse / value_range) if valid_nrmse else np.nan
    r2 = float(1.0 - ss_res / ss_tot) if valid_r2 else np.nan

    return {
        "rmse": rmse,
        "mae": mae,
        "bias": bias,
        "abs_bias": float(abs(bias)),
        "nrmse": nrmse,
        "r2": r2,
    }


def infer_curve_layout(meta: dict, curve_dim: int) -> dict:
    curve_layout = meta.get("curve_layout")
    if curve_layout is not None:
        return curve_layout

    n_time_points = curve_dim // 3
    return {
        "n_time_points": int(n_time_points),
        "parts": [
            {"name": "log_pressure", "start": 0, "end": n_time_points},
            {"name": "log_derivative", "start": n_time_points, "end": 2 * n_time_points},
            {"name": "slope", "start": 2 * n_time_points, "end": 3 * n_time_points},
        ],
    }


def split_curve_by_layout(curve: np.ndarray, layout: dict) -> dict[str, np.ndarray]:
    parts: dict[str, np.ndarray] = {}
    for part in layout["parts"]:
        start = int(part["start"])
        end = int(part["end"])
        parts[str(part["name"])] = curve[start:end]
    return parts


def resolve_cf(args: argparse.Namespace, cfg: Config) -> float:
    if args.Cf is not None:
        return float(args.Cf)

    fixed_cfg = cfg.raw.get("params", {}).get("fixed_params", {}).get("Cf", {}) or {}
    if bool(fixed_cfg.get("enabled", False)):
        return float(fixed_cfg["value"])

    raise ValueError("Cf 未在命令行提供，且配置文件里也没有启用固定 Cf")


def parse_float_list(raw: str, name: str) -> list[float]:
    values: list[float] = []
    for token in raw.replace(";", ",").replace(" ", ",").split(","):
        token = token.strip()
        if not token:
            continue
        values.append(float(token))
    if not values:
        raise ValueError(f"{name} 不能为空")
    return values


def resolve_case_schedule(cfg: Config, args: argparse.Namespace | None = None) -> Schedule:
    if args is not None and (args.timeQ is not None or args.q is not None or args.section_index is not None):
        if args.timeQ is None or args.q is None:
            raise ValueError("覆盖流量制度时必须同时提供 --timeQ 和 --q")

        timeQ = parse_float_list(args.timeQ, "--timeQ")
        q = parse_float_list(args.q, "--q")
        if len(timeQ) != len(q):
            raise ValueError(f"--timeQ 和 --q 长度必须一致，当前分别为 {len(timeQ)} 和 {len(q)}")

        # Allow the reporting/table convention with an initial "0 0" row.
        if len(timeQ) >= 2 and timeQ[0] <= 0.0 and q[0] == 0.0:
            timeQ = timeQ[1:]
            q = q[1:]

        section_index = int(args.section_index) if args.section_index is not None else len(timeQ)
        schedule = Schedule(sectionIndex=section_index, timeQ=timeQ, q=q)
        if not schedule.validate():
            raise ValueError(
                "命令行覆盖的流量制度非法。注意 compare 脚本里的 timeQ 表示每段持续时间，"
                "如果有初始行请写成 0,0；有效段必须 timeQ>0 且 q>=0。"
            )
        return schedule

    schedule_cfg = cfg.raw["schedule"]["case_schedule"]
    timeQ = list(map(float, schedule_cfg["timeQ"]))
    q = list(map(float, schedule_cfg["q"]))

    policy = cfg.raw["schedule"].get("section_policy", {}) or {}
    mode = str(policy.get("mode", "fixed_last")).lower()
    n_sections = len(timeQ)

    if mode == "fixed_last":
        section_index = n_sections
    elif mode == "fixed_value":
        section_index = int(np.clip(int(policy.get("fixed_value", n_sections)), 1, n_sections))
    else:
        section_index = int(np.clip(int(schedule_cfg.get("default_section_index", n_sections)), 1, n_sections))

    schedule = Schedule(sectionIndex=section_index, timeQ=timeQ, q=q)
    if not schedule.validate():
        raise ValueError("配置文件中的 case_schedule 非法，无法用于单样本对比")
    return schedule


def resolve_paths(args: argparse.Namespace) -> tuple[Config, Path, Path, Path]:
    tag = normalize_tag(args.tag)

    config_path = args.config
    if config_path is None:
        config_path = str(config_for_stage(args.stage) or Path("configs/data_gen_family_random.yaml"))

    processed_path = Path(args.processed) if args.processed is not None else processed_path_for_tag(tag)
    model_path = (
        Path(args.model)
        if args.model is not None
        else model_checkpoint_for_tag(tag, use_schedule=not args.no_schedule)
    )

    if args.output_dir is not None:
        output_dir = Path(args.output_dir)
    else:
        suffix = "" if not args.no_schedule else "_no_schedule"
        output_dir = Path("results") / (f"single_compare_{tag}{suffix}" if tag else f"single_compare{suffix}")

    return Config(config_path), processed_path, model_path, output_dir


def build_params_from_args(args: argparse.Namespace, cfg: Config, schedule: Schedule) -> Params:
    return Params(
        k=float(args.k),
        skin=float(args.skin),
        wellboreC=float(args.wellboreC),
        phi=float(args.phi),
        h=float(args.h),
        Cf=resolve_cf(args, cfg),
        schedule=schedule,
    )


def run_solver_and_extract_curve(cfg: Config, params: Params, well_index: int) -> tuple[np.ndarray, dict]:
    runner = CppRunner(cfg=cfg)
    try:
        ok = runner.run_simulation(params, override_schedule=params.schedule, include_schedule=True)
        result = read_result_bin(runner.result_bin) if runner.result_bin.exists() else None
        if not ok and result is None:
            raise RuntimeError("求解器运行失败，未生成有效结果")
        if not ok and result is not None:
            print("Warning: runner_client 返回失败，但 result.bin 可读取，继续使用求解器结果。")

        if result is None:
            raise RuntimeError("无法读取 result.bin")
        if not result["loglog"]:
            raise RuntimeError("求解器未返回 loglog 数据")

        if well_index < 0 or well_index >= len(result["loglog"]):
            raise IndexError(f"well-index={well_index} 超出范围，可用井数={len(result['loglog'])}")

        loglog = result["loglog"][well_index]
        t = np.asarray(loglog["t"], dtype=np.float64)
        p = np.asarray(loglog["p"], dtype=np.float64)
        d = np.asarray(loglog["deriv"], dtype=np.float64)

        cleaned = clean_curve_for_dataset(cfg, t, p, d)
        if cleaned is None:
            raise RuntimeError("求解器返回曲线在清洗后无效")

        t_clean, p_clean, d_clean = cleaned
        valid, reason = is_valid_curve(cfg, t_clean, p_clean, d_clean)
        if not valid:
            raise RuntimeError(f"求解器曲线未通过有效性检查: {reason}")

        curve_feat = resample_curve_to_features(cfg, t_clean, p_clean, d_clean)
        raw = {
            "t": t_clean.tolist(),
            "p": p_clean.tolist(),
            "d": d_clean.tolist(),
            "n_steps": int(result["nSteps"]),
            "n_wells": int(result["nWells"]),
        }
        return curve_feat, raw
    finally:
        runner.close()


def build_schedule_vector(cfg: Config, schedule: Schedule) -> np.ndarray:
    return build_schedule_model_vector(cfg, schedule)


def load_model(checkpoint_path: Path) -> tuple[ForwardSurrogate, bool, torch.device]:
    checkpoint = torch.load(checkpoint_path, map_location="cpu")
    use_schedule = bool(checkpoint.get("use_schedule", True))

    model = ForwardSurrogate(
        param_dim=int(checkpoint["param_dim"]),
        schedule_dim=int(checkpoint["schedule_dim"]),
        curve_dim=int(checkpoint["curve_dim"]),
        hidden_dim=int(checkpoint["hidden_dim"]),
        dropout=float(checkpoint["dropout"]),
        use_schedule=use_schedule,
    )
    model.load_state_dict(checkpoint["model_state_dict"])
    model.eval()

    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    model = model.to(device)
    return model, use_schedule, device


def predict_surrogate_curve(
    processed: dict,
    model: ForwardSurrogate,
    device: torch.device,
    use_schedule: bool,
    params: Params,
    schedule: Schedule,
    cfg: Config,
) -> np.ndarray:
    scaler_params = processed["scaler_params"]
    scaler_schedule = processed["scaler_schedule"]
    scaler_curve = processed["scaler_curve"]
    param_transform = param_feature_transform_from_meta(processed.get("meta", {}))

    params_vec = np.asarray(
        [params.k, params.skin, params.wellboreC, params.phi, params.h, params.Cf],
        dtype=np.float32,
    ).reshape(1, -1)
    schedule_vec = build_schedule_vector(cfg, schedule).reshape(1, -1)

    params_x = scaler_params.transform(transform_param_features(params_vec, param_transform)).astype(np.float32)
    schedule_x = scaler_schedule.transform(schedule_vec).astype(np.float32)

    with torch.no_grad():
        params_t = torch.tensor(params_x, dtype=torch.float32, device=device)
        if use_schedule:
            schedule_t = torch.tensor(schedule_x, dtype=torch.float32, device=device)
            pred_scaled = model(params_t, schedule_t).cpu().numpy()
        else:
            pred_scaled = model(params_t, None).cpu().numpy()

    return scaler_curve.inverse_transform(pred_scaled)[0].astype(np.float32)


def plot_comparison(
    curve_true: np.ndarray,
    curve_pred: np.ndarray,
    curve_layout: dict,
    output_path: Path,
    params: Params,
    schedule: Schedule,
    model_path: Path,
    use_schedule: bool,
) -> dict:
    true_parts = split_curve_by_layout(curve_true, curve_layout)
    pred_parts = split_curve_by_layout(curve_pred, curve_layout)
    overall = calc_metrics(curve_true, curve_pred)
    autofit = dual_log_objective(curve_true, curve_pred, curve_layout)

    part_names = ["log_pressure", "log_derivative", "slope"]
    title_map = {
        "log_pressure": "Log Pressure",
        "log_derivative": "Log |Derivative|",
        "slope": "Slope of Log Pressure vs Log Time",
    }

    fig, axes = plt.subplots(3, 2, figsize=(14, 12))
    fig.suptitle(
        "Solver vs Surrogate\n"
        f"k={params.k:.6g}, skin={params.skin:.6g}, wellboreC={params.wellboreC:.6g}, "
        f"phi={params.phi:.6g}, h={params.h:.6g}, Cf={params.Cf:.6g}\n"
        f"sectionIndex={schedule.sectionIndex}, timeQ={schedule.timeQ}, q={schedule.q}\n"
        f"use_schedule={use_schedule}, model={model_path.name}, "
        f"Overall RMSE={overall['rmse']:.4f}, MAE={overall['mae']:.4f}, "
        f"AutoFitObj={autofit['dual_log_objective']:.4f}, "
        f"R2={'nan' if np.isnan(overall['r2']) else f'{overall['r2']:.4f}'}"
    )

    summary = {"overall": overall, "autofit": autofit, "parts": {}}

    for row, name in enumerate(part_names):
        y_true = true_parts[name]
        y_pred = pred_parts[name]
        err = y_pred - y_true
        x = np.arange(len(y_true))
        metrics = calc_metrics(y_true, y_pred)
        summary["parts"][name] = metrics

        nrmse_text = "nan" if np.isnan(metrics["nrmse"]) else f"{metrics['nrmse']:.4f}"
        r2_text = "nan" if np.isnan(metrics["r2"]) else f"{metrics['r2']:.4f}"

        ax_l = axes[row, 0]
        ax_l.plot(x, y_true, label="Solver", linewidth=2, alpha=0.85)
        ax_l.plot(x, y_pred, label="Surrogate", linewidth=2, alpha=0.85)
        ax_l.set_title(
            f"{title_map[name]} | RMSE={metrics['rmse']:.4f}, MAE={metrics['mae']:.4f}, "
            f"Bias={metrics['bias']:.4f}, NRMSE={nrmse_text}, R2={r2_text}"
        )
        ax_l.set_xlabel("Resampled Time Index")
        ax_l.set_ylabel("Value")
        ax_l.grid(True, alpha=0.3)
        ax_l.legend()

        ax_r = axes[row, 1]
        ax_r.plot(x, err, linewidth=1.5, alpha=0.85)
        ax_r.axhline(0.0, linestyle="--", linewidth=1)
        ax_r.set_title(f"{title_map[name]} Error")
        ax_r.set_xlabel("Resampled Time Index")
        ax_r.set_ylabel("Surrogate - Solver")
        ax_r.grid(True, alpha=0.3)

    plt.tight_layout(rect=[0, 0, 1, 0.94])
    plt.savefig(output_path, dpi=150, bbox_inches="tight")
    plt.close()
    return summary


def main() -> None:
    args = parse_args()
    cfg, processed_path, model_path, output_dir = resolve_paths(args)
    output_dir.mkdir(parents=True, exist_ok=True)

    if not processed_path.exists():
        raise FileNotFoundError(f"Processed 数据不存在: {processed_path}")
    if not model_path.exists():
        raise FileNotFoundError(f"模型 checkpoint 不存在: {model_path}")

    processed = joblib.load(processed_path)
    curve_layout = infer_curve_layout(processed["meta"], int(processed["meta"]["curve_dim"]))

    schedule = resolve_case_schedule(cfg, args)
    params = build_params_from_args(args, cfg, schedule)

    print("Running solver...")
    curve_solver, raw_solver = run_solver_and_extract_curve(cfg, params, args.well_index)

    print("Running surrogate...")
    model, use_schedule, device = load_model(model_path)
    curve_pred = predict_surrogate_curve(
        processed=processed,
        model=model,
        device=device,
        use_schedule=use_schedule,
        params=params,
        schedule=schedule,
        cfg=cfg,
    )

    plot_path = output_dir / "single_case_comparison.png"
    summary = plot_comparison(
        curve_true=curve_solver,
        curve_pred=curve_pred,
        curve_layout=curve_layout,
        output_path=plot_path,
        params=params,
        schedule=schedule,
        model_path=model_path,
        use_schedule=use_schedule,
    )

    summary_payload = {
        "config_path": str(cfg.path),
        "processed_path": str(processed_path),
        "model_path": str(model_path),
        "use_schedule": use_schedule,
        "device": str(device),
        "params": {
            "k": params.k,
            "skin": params.skin,
            "wellboreC": params.wellboreC,
            "phi": params.phi,
            "h": params.h,
            "Cf": params.Cf,
        },
        "schedule": {
            "sectionIndex": schedule.sectionIndex,
            "timeQ": schedule.timeQ,
            "q": schedule.q,
        },
        "metrics": summary,
        "solver_raw_loglog": raw_solver,
    }

    with open(output_dir / "single_case_summary.json", "w", encoding="utf-8") as f:
        json.dump(summary_payload, f, ensure_ascii=False, indent=2)

    overall = summary["overall"]
    autofit = summary["autofit"]
    print("\nSingle-case comparison complete.")
    print(f"Output dir: {output_dir}")
    print(
        f"Overall RMSE={overall['rmse']:.6f}, MAE={overall['mae']:.6f}, "
        f"Bias={overall['bias']:.6f}, "
        f"AutoFitObj={autofit['dual_log_objective']:.6f}, "
        f"R2={'nan' if np.isnan(overall['r2']) else f'{overall['r2']:.6f}'}"
    )
    print(f"Plot saved: {plot_path}")
    print(f"Summary saved: {output_dir / 'single_case_summary.json'}")


if __name__ == "__main__":
    main()