"""
Utility Functions Module

Provides background color calculation, style generation, and other auxiliary functions.
"""

from typing import Tuple


def calculate_bg_color(player_score: int, ai_score: int) -> str:
    """
    Calculate background color based on player and AI scores

    Rules:
    - Player leading: Green gradient (light green to dark green)
    - AI leading: Red gradient (light red to dark red)
    - Tie: White

    Args:
        player_score: Player score
        ai_score: AI score

    Returns:
        RGB color string in format "rgb(r, g, b)"
    """
    # Return white for tie
    if player_score == ai_score:
        return "rgb(255, 255, 255)"

    # Calculate score difference
    score_diff = player_score - ai_score

    # Player leading - green gradient
    if score_diff > 0:
        # Higher difference, darker green
        # Lightest: rgb(230, 255, 230) - difference of 1
        # Darkest: rgb(144, 238, 144) - difference of 5+
        intensity = min(score_diff, 5)  # Limit max difference to 5

        # Linear interpolation for RGB values
        r = int(230 - (86 * intensity / 5))  # 230 -> 144
        g = int(255 - (17 * intensity / 5))  # 255 -> 238
        b = int(230 - (86 * intensity / 5))  # 230 -> 144

        return f"rgb({r}, {g}, {b})"

    # AI leading - red gradient
    else:
        # Higher difference, darker red
        # Lightest: rgb(255, 230, 230) - difference of 1
        # Darkest: rgb(255, 182, 193) - difference of 5+
        intensity = min(abs(score_diff), 5)  # Limit max difference to 5

        # Linear interpolation for RGB values
        r = 255  # Keep red channel at maximum
        g = int(230 - (48 * intensity / 5))  # 230 -> 182
        b = int(230 - (37 * intensity / 5))  # 230 -> 193

        return f"rgb({r}, {g}, {b})"


def get_background_style(player_score: int, ai_score: int) -> str:
    """
    Generate complete background style CSS string

    Args:
        player_score: Player score
        ai_score: AI score

    Returns:
        CSS style string including background color and transition effect
    """
    bg_color = calculate_bg_color(player_score, ai_score)

    return f"""
        background-color: {bg_color};
        transition: background-color 0.5s ease;
    """


def format_confidence(confidence: float) -> str:
    """
    Format confidence as percentage string

    Args:
        confidence: Confidence value between 0.0-1.0

    Returns:
        Formatted percentage string, e.g. "85.3%"
    """
    return f"{confidence * 100:.1f}%"


def validate_image_path(path: str) -> bool:
    """
    Validate if image path is valid

    Args:
        path: Image file path

    Returns:
        True if path is valid and file exists, otherwise False
    """
    import os
    from pathlib import Path

    if not path:
        return False

    file_path = Path(path)

    # Check if file exists
    if not file_path.exists() or not file_path.is_file():
        return False

    # Check file extension
    valid_extensions = {'.jpg', '.jpeg', '.png', '.webp', '.bmp'}
    if file_path.suffix.lower() not in valid_extensions:
        return False

    return True


def get_score_diff_description(player_score: int, ai_score: int) -> str:
    """
    Get text description of score difference

    Args:
        player_score: Player score
        ai_score: AI score

    Returns:
        Text describing score status, e.g. "You're ahead by 3 points"
    """
    diff = player_score - ai_score

    if diff == 0:
        return "Tie"
    elif diff > 0:
        return f"You're ahead by {diff} point{'s' if diff > 1 else ''}"
    else:
        return f"AI is ahead by {abs(diff)} point{'s' if abs(diff) > 1 else ''}"