"""Image Service: part image upload, processing, and storage.

Stores images at:
  /home/Autopartes/data/images/parts/<tenant_id>/<item_id>_full.webp
  /home/Autopartes/data/images/parts/<tenant_id>/<item_id>_thumb.webp

Serves statically via Flask at /pos/static/images/parts/<tenant_id>/<filename>
"""

import os
import uuid
import requests
from io import BytesIO
from PIL import Image

# Base directories
DATA_DIR = '/home/Autopartes/data/images/parts'
STATIC_DIR = '/home/Autopartes/pos/static/images/parts'

# Image processing settings
MAX_WIDTH = 1200
THUMB_SIZE = (300, 300)
FORMAT = 'WEBP'
QUALITY = 85
THUMB_QUALITY = 80


def _ensure_dir(path):
    os.makedirs(path, exist_ok=True)


def _build_paths(tenant_id, item_id):
    """Return (data_dir, static_dir, basename) for an item."""
    ddir = os.path.join(DATA_DIR, str(tenant_id))
    sdir = os.path.join(STATIC_DIR, str(tenant_id))
    basename = str(item_id)
    return ddir, sdir, basename


def _process_image(img):
    """Resize and convert image to WebP. Returns (full_bytes, thumb_bytes)."""
    # Convert to RGB if necessary (e.g. RGBA -> RGB for WEBP compatibility)
    if img.mode in ('RGBA', 'P'):
        img = img.convert('RGB')

    # Resize original if too wide
    w, h = img.size
    if w > MAX_WIDTH:
        ratio = MAX_WIDTH / w
        new_h = int(h * ratio)
        img = img.resize((MAX_WIDTH, new_h), Image.LANCZOS)

    # Full image
    full_buf = BytesIO()
    img.save(full_buf, format=FORMAT, quality=QUALITY, optimize=True)
    full_buf.seek(0)

    # Thumbnail (crop to square from center)
    thumb = img.copy()
    tw, th = thumb.size
    min_dim = min(tw, th)
    left = (tw - min_dim) // 2
    top = (th - min_dim) // 2
    thumb = thumb.crop((left, top, left + min_dim, top + min_dim))
    thumb = thumb.resize(THUMB_SIZE, Image.LANCZOS)

    thumb_buf = BytesIO()
    thumb.save(thumb_buf, format=FORMAT, quality=THUMB_QUALITY, optimize=True)
    thumb_buf.seek(0)

    return full_buf, thumb_buf


def save_image(tenant_id, item_id, file_obj=None, image_url=None,
               filename_hint=None):
    """Save an image for an inventory item.

    Args:
        tenant_id: tenant ID for path isolation
        item_id: inventory item ID
        file_obj: file-like object (from Flask request.files)
        image_url: URL to download image from
        filename_hint: original filename for extension detection

    Returns:
        dict with 'image_url', 'thumb_url', 'size_full', 'size_thumb'
    """
    if not file_obj and not image_url:
        raise ValueError("Either file_obj or image_url is required")

    # Load image
    if file_obj:
        img = Image.open(file_obj)
    else:
        resp = requests.get(image_url, timeout=30)
        resp.raise_for_status()
        img = Image.open(BytesIO(resp.content))

    # Process
    full_buf, thumb_buf = _process_image(img)

    # Save to filesystem
    ddir, sdir, basename = _build_paths(tenant_id, item_id)
    _ensure_dir(ddir)
    _ensure_dir(sdir)

    full_path = os.path.join(ddir, f"{basename}_full.webp")
    thumb_path = os.path.join(ddir, f"{basename}_thumb.webp")

    # Also symlink/copy to static dir for Flask serving
    static_full = os.path.join(sdir, f"{basename}_full.webp")
    static_thumb = os.path.join(sdir, f"{basename}_thumb.webp")

    with open(full_path, 'wb') as f:
        f.write(full_buf.read())
    with open(thumb_path, 'wb') as f:
        f.write(thumb_buf.read())

    # Copy to static dir
    import shutil
    shutil.copy2(full_path, static_full)
    shutil.copy2(thumb_path, static_thumb)

    # Build URLs
    image_url = f"/pos/static/images/parts/{tenant_id}/{basename}_full.webp"
    thumb_url = f"/pos/static/images/parts/{tenant_id}/{basename}_thumb.webp"

    return {
        'image_url': image_url,
        'thumb_url': thumb_url,
        'size_full': os.path.getsize(full_path),
        'size_thumb': os.path.getsize(thumb_path),
    }


def delete_image(tenant_id, item_id):
    """Delete all images for an inventory item."""
    ddir, sdir, basename = _build_paths(tenant_id, item_id)
    deleted = []

    for directory in [ddir, sdir]:
        for suffix in ['_full.webp', '_thumb.webp']:
            path = os.path.join(directory, f"{basename}{suffix}")
            if os.path.exists(path):
                os.remove(path)
                deleted.append(path)

    return {'deleted': deleted}


def get_image_info(tenant_id, item_id):
    """Get image info for an inventory item."""
    ddir, sdir, basename = _build_paths(tenant_id, item_id)
    full_path = os.path.join(ddir, f"{basename}_full.webp")
    thumb_path = os.path.join(ddir, f"{basename}_thumb.webp")

    info = {'has_image': False, 'image_url': None, 'thumb_url': None}
    if os.path.exists(full_path):
        info['has_image'] = True
        info['image_url'] = f"/pos/static/images/parts/{tenant_id}/{basename}_full.webp"
        info['thumb_url'] = f"/pos/static/images/parts/{tenant_id}/{basename}_thumb.webp"
        info['size_full'] = os.path.getsize(full_path)
        info['size_thumb'] = os.path.getsize(thumb_path)
        info['updated_at'] = os.path.getmtime(full_path)
    return info