# media_storage.py - File-based media storage manager (v4.3)

import os
import base64
import shutil

from config import MEDIA_STORAGE_DIR


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


def get_project_dir(project_id):
    """প্রজেক্টের base ডিরেক্টরি (absolute path) রিটার্ন করে।"""
    return os.path.join(MEDIA_STORAGE_DIR, f'project_{int(project_id)}')


def get_audio_dir(project_id):
    return os.path.join(get_project_dir(project_id), 'audio')


def get_images_dir(project_id):
    return os.path.join(get_project_dir(project_id), 'images')


# ============================================
# Save operations (base64 string → file)
# ============================================

def save_audio(project_id, block_id, audio_base64, audio_format='mp3'):
    """
    Audio ফাইল সেভ করে relative path রিটার্ন করে।
    relative path ডেটাবেসে জমা হবে, যেমন: project_5/audio/block_123.mp3
    """
    if not audio_base64:
        return None
    audio_dir = get_audio_dir(project_id)
    _ensure_dir(audio_dir)
    fmt = (audio_format or 'mp3').lower()
    filename = f'block_{int(block_id)}.{fmt}'
    abs_path = os.path.join(audio_dir, filename)
    with open(abs_path, 'wb') as f:
        f.write(base64.b64decode(audio_base64))
    return f'project_{int(project_id)}/audio/{filename}'


def save_image(project_id, image_id, image_base64, image_format='png'):
    """Image ফাইল সেভ করে relative path রিটার্ন করে।"""
    if not image_base64:
        return None
    images_dir = get_images_dir(project_id)
    _ensure_dir(images_dir)
    fmt = (image_format or 'png').lower()
    filename = f'img_{int(image_id)}.{fmt}'
    abs_path = os.path.join(images_dir, filename)
    with open(abs_path, 'wb') as f:
        f.write(base64.b64decode(image_base64))
    return f'project_{int(project_id)}/images/{filename}'


def save_thumbnail(project_id, image_bytes, image_format='png'):
    """Thumbnail সেভ করে relative path রিটার্ন করে (raw bytes নেয়)।"""
    if not image_bytes:
        return None
    proj_dir = get_project_dir(project_id)
    _ensure_dir(proj_dir)
    fmt = (image_format or 'png').lower()
    filename = f'thumbnail.{fmt}'
    abs_path = os.path.join(proj_dir, filename)
    # পুরোনো thumbnail অন্য ফরম্যাটে থাকলে মুছে দিই
    for old_ext in ('png', 'jpeg', 'jpg', 'webp', 'gif'):
        old = os.path.join(proj_dir, f'thumbnail.{old_ext}')
        if old_ext != fmt and os.path.exists(old):
            try:
                os.remove(old)
            except OSError:
                pass
    with open(abs_path, 'wb') as f:
        f.write(image_bytes)
    return f'project_{int(project_id)}/{filename}'


# ============================================
# Read operations (file → bytes / base64)
# ============================================

def _safe_abs_path(relative_path):
    """
    relative path কে absolute path-এ রূপান্তর করে এবং নিশ্চিত করে
    যে এটা MEDIA_STORAGE_DIR-এর বাইরে যাচ্ছে না (path traversal রোধ)।
    """
    if not relative_path:
        return None
    base = os.path.realpath(MEDIA_STORAGE_DIR)
    abs_path = os.path.realpath(os.path.join(base, relative_path))
    if not abs_path.startswith(base + os.sep) and abs_path != base:
        return None  # নিরাপত্তা লঙ্ঘন
    return abs_path


def read_file_bytes(relative_path):
    """ফাইলের raw bytes রিটার্ন করে। না থাকলে None।"""
    abs_path = _safe_abs_path(relative_path)
    if not abs_path or not os.path.exists(abs_path):
        return None
    with open(abs_path, 'rb') as f:
        return f.read()


def read_file_base64(relative_path):
    """ফাইল base64 স্ট্রিং হিসেবে রিটার্ন করে। না থাকলে খালি স্ট্রিং।"""
    data = read_file_bytes(relative_path)
    if data is None:
        return ''
    return base64.b64encode(data).decode('utf-8')


def get_safe_abs_path(relative_path):
    """Flask send_file-এর জন্য নিরাপদ absolute path।"""
    return _safe_abs_path(relative_path)


# ============================================
# Storage stats (v4.3)
# ============================================

def get_storage_usage_bytes():
    """media-storage ফোল্ডারের মোট সাইজ (bytes) রিটার্ন করে।"""
    total = 0
    if not os.path.exists(MEDIA_STORAGE_DIR):
        return 0
    for root, _, files in os.walk(MEDIA_STORAGE_DIR):
        for name in files:
            fp = os.path.join(root, name)
            try:
                total += os.path.getsize(fp)
            except OSError:
                pass
    return total


# ============================================
# Pending thumbnails (v4.4) — আপলোডের সময় জেনারেট, সেভের সময় commit
# ============================================

import uuid as _uuid

def _pending_thumbs_dir():
    return os.path.join(MEDIA_STORAGE_DIR, '_pending_thumbs')


def save_pending_thumbnail(image_bytes, image_format='jpeg'):
    """
    অস্থায়ী থাম্বনেইল সেভ করে একটা token রিটার্ন করে।
    প্রজেক্ট এখনো তৈরি হয়নি বলে project_id ছাড়াই রাখা হয়।
    """
    if not image_bytes:
        return None
    d = _pending_thumbs_dir()
    _ensure_dir(d)
    fmt = (image_format or 'jpeg').lower()
    token = _uuid.uuid4().hex
    filename = f'{token}.{fmt}'
    with open(os.path.join(d, filename), 'wb') as f:
        f.write(image_bytes)
    return filename  # token = filename


def read_pending_thumbnail(token):
    """Pending thumbnail-এর (bytes, format) ফেরত দেয়। না থাকলে (None, None)।"""
    if not token or '/' in token or '\\' in token or '..' in token:
        return None, None
    path = os.path.join(_pending_thumbs_dir(), token)
    if not os.path.exists(path):
        return None, None
    fmt = token.rsplit('.', 1)[-1] if '.' in token else 'jpeg'
    with open(path, 'rb') as f:
        return f.read(), fmt


def delete_pending_thumbnail(token):
    """Pending thumbnail মুছে দেয় (commit বা বাতিলের পর)।"""
    if not token or '/' in token or '\\' in token or '..' in token:
        return
    path = os.path.join(_pending_thumbs_dir(), token)
    if os.path.exists(path):
        try:
            os.remove(path)
        except OSError:
            pass


# ============================================
# Delete operations
# ============================================

def delete_project_media(project_id):
    """প্রজেক্টের পুরো media ফোল্ডার মুছে দেয় (প্রজেক্ট ডিলিটের সময়)।"""
    proj_dir = get_project_dir(project_id)
    if os.path.exists(proj_dir):
        try:
            shutil.rmtree(proj_dir)
            print(f"🗑️ Deleted media folder: {proj_dir}")
            return True
        except OSError as e:
            print(f"⚠️ Failed to delete media folder {proj_dir}: {e}")
            return False
    return False


def delete_file(relative_path):
    """একটা নির্দিষ্ট ফাইল মুছে দেয়।"""
    abs_path = _safe_abs_path(relative_path)
    if abs_path and os.path.exists(abs_path):
        try:
            os.remove(abs_path)
            return True
        except OSError:
            return False
    return False