# image_processor.py

import os
import math
import logging
from typing import Optional, List, Dict, Tuple

try:
    from PIL import Image, ImageDraw, ImageFont

    PIL_AVAILABLE = True
except ImportError:
    PIL_AVAILABLE = False

    # Definisci classi dummy se PIL non c'è, per evitare errori altrove
    class Image:
        pass

    class ImageDraw:
        pass

    class ImageFont:
        pass

    logging.error(
        "Pillow library (PIL) not found. Image processing features will be disabled."
    )

# Costanti per disegno (possono essere spostate in config se necessario)
TILE_TEXT_COLOR = "white"
TILE_TEXT_BG_COLOR = "black"  # Sfondo opaco
PLACEHOLDER_COLOR = (128, 128, 128)  # Grigio per placeholder RGB
TILE_BORDER_COLOR = "red"
TILE_BORDER_WIDTH = 2  # Spessore bordo griglia

# Carica font (una sola volta)
DEFAULT_FONT = None
if PIL_AVAILABLE:
    try:
        # Prova diversi font comuni
        font_paths = [
            "arial.ttf",
            "LiberationSans-Regular.ttf",
            "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
        ]
        for font_path in font_paths:
            try:
                DEFAULT_FONT = ImageFont.truetype(
                    font_path, 12
                )  # Aumenta dimensione font
                logging.info(f"Loaded font: {font_path}")
                break
            except IOError:
                continue  # Prova il prossimo
        if DEFAULT_FONT is None:
            DEFAULT_FONT = ImageFont.load_default()
            logging.warning("Common system fonts not found, using default PIL font.")
    except Exception as e:
        logging.error(f"Error loading font: {e}")
        DEFAULT_FONT = ImageFont.load_default() if PIL_AVAILABLE else None


def add_overlay_info(
    image: Optional[Image.Image], tile_name: str, source_text: str = "NASADEM"
) -> Optional[Image.Image]:
    """
    Draws tile name and source information onto a PIL Image object.

    Args:
        image (Optional[Image.Image]): The PIL Image object to draw on. If None, does nothing.
        tile_name (str): The base name of the tile (e.g., 'n45e007').
        source_text (str): Text indicating the data source.

    Returns:
        Optional[Image.Image]: The modified image object, or None if input was None or PIL unavailable.
    """
    if not PIL_AVAILABLE or image is None:
        return None

    try:
        # Assicurati sia modificabile (RGB o RGBA)
        if image.mode not in ["RGB", "RGBA"]:
            image = image.convert("RGB")

        draw = ImageDraw.Draw(image)
        text = f"{tile_name.upper()}\nSource: {source_text}"
        font = DEFAULT_FONT if DEFAULT_FONT else ImageFont.load_default()

        # Calcola dimensioni testo per posizionamento
        try:
            # textbbox è più preciso ma richiede Pillow >= 8.0.0
            text_bbox = draw.textbbox((0, 0), text, font=font)
            text_width = text_bbox[2] - text_bbox[0]
            text_height = text_bbox[3] - text_bbox[1]
        except AttributeError:
            # Fallback per versioni Pillow più vecchie
            text_width, text_height = draw.textsize(text, font=font)

        margin = 5
        text_x = image.width - text_width - margin
        text_y = image.height - text_height - margin

        # Disegna sfondo e testo
        bg_coords = [
            text_x - 2,
            text_y - 2,
            text_x + text_width + 2,
            text_y + text_height + 2,
        ]
        draw.rectangle(bg_coords, fill=TILE_TEXT_BG_COLOR)
        draw.text((text_x, text_y), text, fill=TILE_TEXT_COLOR, font=font)

        return image

    except Exception as e:
        logging.error(
            f"Error adding overlay to image for {tile_name}: {e}", exc_info=True
        )
        return image  # Restituisci immagine originale in caso di errore


def load_prepare_single_browse(
    image_path: Optional[str], tile_name: str
) -> Optional[Image.Image]:
    """
    Loads a browse image from path, adds overlay info.

    Args:
        image_path (Optional[str]): Path to the browse image file.
        tile_name (str): Base name of the tile (e.g., 'n45e007').

    Returns:
        Optional[Image.Image]: Prepared PIL Image object or None if loading/processing fails.
    """
    if not PIL_AVAILABLE or not image_path or not os.path.exists(image_path):
        return None

    try:
        logging.debug(f"Loading browse image: {image_path}")
        img = Image.open(image_path)
        img_with_overlay = add_overlay_info(img, tile_name)
        return img_with_overlay
    except Exception as e:
        logging.error(
            f"Failed to load or prepare browse image {image_path}: {e}", exc_info=True
        )
        return None


def create_composite_area_image(
    tile_info_list: List[Dict], target_tile_size: Optional[Tuple[int, int]] = None
) -> Optional[Image.Image]:
    """
    Creates a composite image by mosaicking available browse images for an area.

    Args:
        tile_info_list (List[Dict]): List of dictionaries from ElevationManager.get_area_tile_info.
        target_tile_size (Optional[Tuple[int, int]]): If provided, resize each tile to this size.
                                                      Otherwise, uses max dimensions found.

    Returns:
        Optional[Image.Image]: Composite PIL Image object or None if no tiles or error.
    """
    if not PIL_AVAILABLE or not tile_info_list:
        logging.warning(
            "Cannot create composite image: PIL unavailable or no tile info provided."
        )
        return None

    logging.info(f"Creating composite image for {len(tile_info_list)} tile area.")

    # Estrai coordinate min/max per determinare la griglia
    lats = [info["latitude_coord"] for info in tile_info_list]
    lons = [info["longitude_coord"] for info in tile_info_list]
    if not lats or not lons:
        return None  # Lista vuota?
    min_lat, max_lat = min(lats), max(lats)
    min_lon, max_lon = min(lons), max(lons)

    num_lat_tiles = max_lat - min_lat + 1
    num_lon_tiles = max_lon - min_lon + 1

    # Carica immagini e determina dimensioni massime (o usa target)
    tile_images: Dict[Tuple[int, int], Optional[Image.Image]] = {}
    max_w, max_h = 0, 0
    loaded_image_count = 0

    for info in tile_info_list:
        lat, lon = info["latitude_coord"], info["longitude_coord"]
        key = (lat, lon)
        img_path = info.get("browse_image_path")
        img = None
        if img_path and os.path.exists(img_path):
            try:
                img = Image.open(img_path).convert("RGB")  # Carica come RGB
                tile_images[key] = img
                if not target_tile_size:  # Se non forziamo dimensione, trova max
                    max_w = max(max_w, img.width)
                    max_h = max(max_h, img.height)
                loaded_image_count += 1
            except Exception as e:
                logging.warning(f"Could not load browse image {img_path}: {e}")
                tile_images[key] = None  # Segna come non caricata
        else:
            tile_images[key] = None  # Non disponibile

    if loaded_image_count == 0:
        logging.warning("No browse images available for the specified area.")
        # Potremmo restituire None o un'immagine placeholder unica? Per ora None.
        return None

    # Imposta dimensione cella: target o massima trovata
    tile_w = target_tile_size[0] if target_tile_size else max_w
    tile_h = target_tile_size[1] if target_tile_size else max_h
    if tile_w <= 0 or tile_h <= 0:
        logging.error(
            "Invalid target tile size or no valid images found to determine size."
        )
        return None  # Dimensione non valida

    # Crea immagine composita
    total_width = num_lon_tiles * tile_w
    total_height = num_lat_tiles * tile_h
    logging.info(
        f"Creating composite canvas: {total_width}x{total_height} ({num_lon_tiles}x{num_lat_tiles} tiles of {tile_w}x{tile_h})"
    )
    composite_img = Image.new("RGB", (total_width, total_height), PLACEHOLDER_COLOR)
    draw = ImageDraw.Draw(composite_img)

    # Incolla tile, disegna griglia e testo
    for r, lat_coord in enumerate(
        range(max_lat, min_lat - 1, -1)
    ):  # Y cresce verso il basso (Nord in alto)
        for c, lon_coord in enumerate(
            range(min_lon, max_lon + 1)
        ):  # X cresce verso destra (Ovest a sinistra)
            key = (lat_coord, lon_coord)
            img = tile_images.get(key)

            paste_x = c * tile_w
            paste_y = r * tile_h

            if img:
                # Ridimensiona se necessario
                if img.width != tile_w or img.height != tile_h:
                    img = img.resize((tile_w, tile_h), Image.Resampling.LANCZOS)
                composite_img.paste(img, (paste_x, paste_y))

            # Disegna bordo
            draw.rectangle(
                [paste_x, paste_y, paste_x + tile_w - 1, paste_y + tile_h - 1],
                outline=TILE_BORDER_COLOR,
                width=TILE_BORDER_WIDTH,
            )

            # Aggiungi etichetta (riutilizza logica)
            tile_name = f"{'N' if lat_coord >= 0 else 'S'}{abs(lat_coord):02d}{'E' if lon_coord >= 0 else 'W'}{abs(lon_coord):03d}"
            add_overlay_info(
                composite_img.crop(
                    (paste_x, paste_y, paste_x + tile_w, paste_y + tile_h)
                ),  # Disegna su un crop temporaneo? No, direttamente sulla composita
                tile_name,
                source_text="",
            )  # Passa empty source? O solo nome tile?

            # Disegna nome tile direttamente sulla composita
            font = DEFAULT_FONT if DEFAULT_FONT else ImageFont.load_default()
            text = tile_name
            try:
                text_bbox = draw.textbbox((0, 0), text, font=font)
                text_w = text_bbox[2] - text_bbox[0]
                text_h = text_bbox[3] - text_bbox[1]
            except AttributeError:
                text_w, text_h = draw.textsize(text, font=font)  # Fallback
            margin = 3
            text_pos_x = paste_x + tile_w - text_w - margin
            text_pos_y = paste_y + tile_h - text_h - margin
            bg_coords = [
                text_pos_x - 1,
                text_pos_y - 1,
                text_pos_x + text_w + 1,
                text_pos_y + text_h + 1,
            ]
            draw.rectangle(bg_coords, fill=TILE_TEXT_BG_COLOR)
            draw.text((text_pos_x, text_pos_y), text, fill=TILE_TEXT_COLOR, font=font)

    logging.info("Composite image created successfully.")
    return composite_img