"""
Generate quality charts from a single-model benchmark report.

Usage:
    python benchmark/benchmark_charts.py --report benchmark/report.json
    python benchmark/benchmark_charts.py --report benchmark/report.json --output-dir benchmark/charts
"""

from __future__ import annotations

import argparse
import json
from pathlib import Path

import matplotlib.pyplot as plt
import matplotlib.ticker as mticker
import numpy as np

BENCHMARK_DIR = Path(__file__).resolve().parent
DEFAULT_OUTPUT_DIR = BENCHMARK_DIR / "charts"

COLOR = "#55A868"

METRIC_LABELS = [
    ("intent_accuracy", "Intent accuracy"),
    ("intent_parse_rate", "Intent parse rate"),
    ("clean_output_rate", "Clean output rate"),
    ("slot_presence", "Slot presence"),
]


def _pct_axis(ax) -> None:
    ax.yaxis.set_major_formatter(mticker.PercentFormatter(xmax=1.0, decimals=0))
    ax.set_ylim(0, 1.05)


def _model_from_report(data: dict) -> dict:
    models = data.get("models") or []
    if len(models) != 1:
        raise ValueError("Report must contain exactly one model.")
    return models[0]


def save_overall_metrics_chart(model: dict, output_path: Path) -> None:
    labels = [label for _, label in METRIC_LABELS]
    keys = [key for key, _ in METRIC_LABELS]
    values = [model[key] for key in keys]

    x = np.arange(len(labels))
    width = 0.5

    fig, ax = plt.subplots(figsize=(9, 5))
    bars = ax.bar(x, values, width, label=model["name"], color=COLOR)

    ax.set_title("Overall Quality Metrics")
    ax.set_xticks(x)
    ax.set_xticklabels(labels, rotation=15, ha="right")
    ax.set_ylabel("Score")
    _pct_axis(ax)
    ax.legend(loc="lower right")
    ax.grid(axis="y", alpha=0.3)
    ax.bar_label(bars, fmt="%.0f%%", padding=2, labels=[f"{v * 100:.0f}%" for v in values])

    fig.tight_layout()
    fig.savefig(output_path, dpi=150)
    plt.close(fig)


def save_per_intent_chart(model: dict, output_path: Path) -> None:
    per_intent = model.get("per_intent") or {}
    intents = sorted(per_intent)
    accuracies = [per_intent[i].get("accuracy", 0.0) for i in intents]

    y = np.arange(len(intents))
    fig_h = max(6, len(intents) * 0.28)
    fig, ax = plt.subplots(figsize=(10, fig_h))
    ax.barh(y, accuracies, color=COLOR)

    ax.set_title("Per-Intent Accuracy")
    ax.set_yticks(y)
    ax.set_yticklabels(intents, fontsize=8)
    ax.set_xlabel("Accuracy")
    ax.invert_yaxis()
    ax.xaxis.set_major_formatter(mticker.PercentFormatter(xmax=1.0, decimals=0))
    ax.set_xlim(0, 1.05)
    ax.grid(axis="x", alpha=0.3)

    fig.tight_layout()
    fig.savefig(output_path, dpi=150)
    plt.close(fig)


def save_charts_from_report(report_path: Path, output_dir: Path) -> list[Path]:
    data = json.loads(report_path.read_text(encoding="utf-8"))
    model = _model_from_report(data)

    output_dir.mkdir(parents=True, exist_ok=True)
    charts = [
        output_dir / "overall_metrics.png",
        output_dir / "per_intent_accuracy.png",
    ]

    save_overall_metrics_chart(model, charts[0])
    save_per_intent_chart(model, charts[1])
    return charts


def main() -> None:
    parser = argparse.ArgumentParser(description="Generate benchmark charts for Smartwatch LM v0.2")
    parser.add_argument("--report", type=Path, required=True, help="JSON report")
    parser.add_argument("--output-dir", type=Path, default=DEFAULT_OUTPUT_DIR)
    args = parser.parse_args()

    if not args.report.is_file():
        raise SystemExit(f"Report not found: {args.report}")

    charts = save_charts_from_report(args.report, args.output_dir)
    print(f"Wrote {len(charts)} charts -> {args.output_dir}")
    for path in charts:
        print(f"  {path.name}")


if __name__ == "__main__":
    main()