from __future__ import annotations

import numpy as np
import cv2
import matplotlib
matplotlib.use('Agg')  # non-interactive backend — safe for CLI/server use
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
from PIL import Image

# Emotion colour palette (matplotlib colour names / hex)
EMOTION_COLORS = {
    'happy':    '#2ecc71',   # green
    'angry':    '#e74c3c',   # red
    'sad':      '#3498db',   # blue
    'fear':     '#e67e22',   # orange
    'surprise': '#f1c40f',   # yellow
    'disgust':  '#9b59b6',   # purple
    'neutral':  '#95a5a6',   # gray
}

# OpenCV BGR equivalents for draw_face_predictions
EMOTION_BGR = {
    'happy':    (0, 200, 80),
    'angry':    (0, 60, 220),
    'sad':      (200, 80, 0),
    'fear':     (0, 130, 230),
    'surprise': (0, 210, 240),
    'disgust':  (150, 50, 130),
    'neutral':  (140, 140, 140),
}


def _emotion_color_mpl(emotion: str) -> str:
    return EMOTION_COLORS.get(emotion, '#555555')


def visualize_prediction(image, result: dict, save_path: str | None = None):
    """
    Side-by-side: left = image, right = horizontal bar chart of probabilities.
    Displays interactively if save_path is None, else saves to file.
    """
    if isinstance(image, np.ndarray):
        pil_img = Image.fromarray(cv2.cvtColor(image, cv2.COLOR_BGR2RGB))
    elif isinstance(image, Image.Image):
        pil_img = image.convert('RGB')
    else:
        pil_img = image

    emotions = list(result['probabilities'].keys())
    probs = [result['probabilities'][e] for e in emotions]
    colors = [_emotion_color_mpl(e) for e in emotions]

    fig, axes = plt.subplots(1, 2, figsize=(12, 5))
    fig.suptitle(
        f"Prediction: {result['emotion'].upper()}  ({result['confidence']*100:.1f}%)",
        fontsize=14, fontweight='bold'
    )

    # Left: image
    axes[0].imshow(pil_img)
    axes[0].axis('off')
    axes[0].set_title('Input Image')

    # Right: horizontal bars
    y_pos = range(len(emotions))
    bars = axes[1].barh(list(y_pos), probs, color=colors, height=0.6)
    axes[1].set_yticks(list(y_pos))
    axes[1].set_yticklabels(emotions, fontsize=11)
    axes[1].set_xlim(0, 1.0)
    axes[1].set_xlabel('Probability')
    axes[1].set_title('Emotion Probabilities')
    axes[1].invert_yaxis()

    for bar, prob in zip(bars, probs):
        axes[1].text(
            bar.get_width() + 0.01, bar.get_y() + bar.get_height() / 2,
            f'{prob*100:.1f}%', va='center', fontsize=9
        )

    plt.tight_layout()

    if save_path:
        plt.savefig(save_path, bbox_inches='tight', dpi=150)
        print(f"[INFO] Visualization saved to: {save_path}")
        plt.close(fig)
    else:
        matplotlib.use('TkAgg')  # try switching for interactive display
        plt.show()


def draw_face_predictions(image: np.ndarray, face_results: list[dict]) -> np.ndarray:
    """
    Draw bounding boxes and emotion labels on image (BGR numpy array).
    Returns annotated copy.
    """
    out = image.copy()
    for res in face_results:
        bbox = res.get('bbox')
        if bbox is None:
            continue
        x, y, w, h = (int(v) for v in bbox)
        emotion = res['emotion']
        conf = res['confidence']
        color = EMOTION_BGR.get(emotion, (200, 200, 200))

        cv2.rectangle(out, (x, y), (x + w, y + h), color, 2)

        label = f"{emotion} {conf*100:.0f}%"
        font = cv2.FONT_HERSHEY_SIMPLEX
        scale, thickness = 0.7, 2
        (tw, th), baseline = cv2.getTextSize(label, font, scale, thickness)

        # Background pill for text
        ty = max(y - 8, th + 4)
        cv2.rectangle(out, (x, ty - th - 4), (x + tw + 4, ty + baseline), color, cv2.FILLED)
        cv2.putText(out, label, (x + 2, ty - 2), font, scale, (255, 255, 255), thickness, cv2.LINE_AA)

    return out


def plot_emotion_bars(probabilities: dict, title: str = '', save_path: str | None = None):
    """Standalone horizontal bar chart of all emotion probabilities."""
    emotions = list(probabilities.keys())
    probs = [probabilities[e] for e in emotions]
    colors = [_emotion_color_mpl(e) for e in emotions]

    fig, ax = plt.subplots(figsize=(7, 4))
    if title:
        ax.set_title(title, fontsize=13)

    y_pos = range(len(emotions))
    bars = ax.barh(list(y_pos), probs, color=colors, height=0.6)
    ax.set_yticks(list(y_pos))
    ax.set_yticklabels(emotions, fontsize=11)
    ax.set_xlim(0, 1.0)
    ax.set_xlabel('Probability')
    ax.invert_yaxis()

    for bar, prob in zip(bars, probs):
        ax.text(
            bar.get_width() + 0.01, bar.get_y() + bar.get_height() / 2,
            f'{prob*100:.1f}%', va='center', fontsize=9
        )

    plt.tight_layout()
    if save_path:
        plt.savefig(save_path, bbox_inches='tight', dpi=150)
        print(f"[INFO] Plot saved to: {save_path}")
        plt.close(fig)
    else:
        plt.show()