import time
import traceback
from urllib.parse import urlparse
import json # Ensure json is imported
import requests

# (Keep the rest of your imports)
from ..utils.network_utils import extract_post_info, prepare_cookies_for_request
from ..config.constants import (
    STYLE_DATE_POST_TITLE
)


def fetch_posts_paginated(api_url_base, headers, offset, logger, cancellation_event=None, pause_event=None, cookies_dict=None):
    """
    Fetches a single page of posts from the API with robust retry logic.
    NEW: Requests only essential fields to keep the response size small and reliable.
    """
    if cancellation_event and cancellation_event.is_set():
        raise RuntimeError("Fetch operation cancelled by user.")
    if pause_event and pause_event.is_set():
        logger("   Post fetching paused...")
        while pause_event.is_set():
            if cancellation_event and cancellation_event.is_set():
                raise RuntimeError("Fetch operation cancelled by user while paused.")
            time.sleep(0.5)
        logger("   Post fetching resumed.")
    
    # --- MODIFICATION: Added `fields` to the URL to request only metadata ---
    # This prevents the large 'content' field from being included in the list, avoiding timeouts.
    fields_to_request = "id,user,service,title,shared_file,added,published,edited,file,attachments,tags"
    paginated_url = f'{api_url_base}?o={offset}&fields={fields_to_request}'
    
    max_retries = 3
    retry_delay = 5

    for attempt in range(max_retries):
        if cancellation_event and cancellation_event.is_set():
            raise RuntimeError("Fetch operation cancelled by user during retry loop.")

        log_message = f"   Fetching post list: {api_url_base}?o={offset} (Page approx. {offset // 50 + 1})"
        if attempt > 0:
            log_message += f" (Attempt {attempt + 1}/{max_retries})"
        logger(log_message)

        try:
            # We can now remove the streaming logic as the response will be small and fast.
            response = requests.get(paginated_url, headers=headers, timeout=(15, 60), cookies=cookies_dict)
            response.raise_for_status()
            return response.json()

        except requests.exceptions.RequestException as e:
            logger(f"   ⚠️ Retryable network error on page fetch (Attempt {attempt + 1}): {e}")
            if attempt < max_retries - 1:
                delay = retry_delay * (2 ** attempt)
                logger(f"      Retrying in {delay} seconds...")
                time.sleep(delay)
                continue
            else:
                logger(f"   ❌ Failed to fetch page after {max_retries} attempts.")
                raise RuntimeError(f"Network error fetching offset {offset}")
        except json.JSONDecodeError as e:
            logger(f"   ❌ Failed to decode JSON on page fetch (Attempt {attempt + 1}): {e}")
            if attempt < max_retries - 1:
                delay = retry_delay * (2 ** attempt)
                logger(f"      Retrying in {delay} seconds...")
                time.sleep(delay)
                continue
            else:
                raise RuntimeError(f"JSONDecodeError fetching offset {offset}")

    raise RuntimeError(f"Failed to fetch page {paginated_url} after all attempts.")


def fetch_single_post_data(api_domain, service, user_id, post_id, headers, logger, cookies_dict=None):
    """
    --- NEW FUNCTION ---
    Fetches the full data, including the 'content' field, for a single post.
    """
    post_api_url = f"https://{api_domain}/api/v1/{service}/user/{user_id}/post/{post_id}"
    logger(f"      Fetching full content for post ID {post_id}...")
    try:
        # Use streaming here as a precaution for single posts that are still very large.
        with requests.get(post_api_url, headers=headers, timeout=(15, 300), cookies=cookies_dict, stream=True) as response:
            response.raise_for_status()
            response_body = b""
            for chunk in response.iter_content(chunk_size=8192):
                response_body += chunk
            
            full_post_data = json.loads(response_body)
            # The API sometimes wraps the post in a list, handle that.
            if isinstance(full_post_data, list) and full_post_data:
                return full_post_data[0]
            return full_post_data
            
    except Exception as e:
        logger(f"      ❌ Failed to fetch full content for post {post_id}: {e}")
        return None

        
def fetch_post_comments(api_domain, service, user_id, post_id, headers, logger, cancellation_event=None, pause_event=None, cookies_dict=None):
    """Fetches all comments for a specific post."""
    if cancellation_event and cancellation_event.is_set():
        raise RuntimeError("Comment fetch operation cancelled by user.")

    comments_api_url = f"https://{api_domain}/api/v1/{service}/user/{user_id}/post/{post_id}/comments"
    logger(f"   Fetching comments: {comments_api_url}")
    
    try:
        response = requests.get(comments_api_url, headers=headers, timeout=(10, 30), cookies=cookies_dict)
        response.raise_for_status()
        return response.json()
    except requests.exceptions.RequestException as e:
        raise RuntimeError(f"Error fetching comments for post {post_id}: {e}")
    except ValueError as e:
        raise RuntimeError(f"Error decoding JSON from comments API for post {post_id}: {e}")

def download_from_api (
api_url_input ,
logger =print ,
start_page =None ,
end_page =None ,
manga_mode =False ,
cancellation_event =None ,
pause_event =None ,
use_cookie =False ,
cookie_text ="",
selected_cookie_file =None ,
app_base_dir =None ,
manga_filename_style_for_sort_check =None 
):
    headers ={
    'User-Agent':'Mozilla/5.0',
    'Accept':'application/json'
    }

    service ,user_id ,target_post_id =extract_post_info (api_url_input )

    if cancellation_event and cancellation_event .is_set ():
        logger ("   Download_from_api cancelled at start.")
        return 

    parsed_input_url_for_domain =urlparse (api_url_input )
    api_domain =parsed_input_url_for_domain .netloc 
    if not any (d in api_domain .lower ()for d in ['kemono.su','kemono.party','coomer.su','coomer.party']):
        logger (f"⚠️ Unrecognized domain '{api_domain }' from input URL. Defaulting to kemono.su for API calls.")
        api_domain ="kemono.su"
    cookies_for_api =None 
    if use_cookie and app_base_dir :
        cookies_for_api =prepare_cookies_for_request (use_cookie ,cookie_text ,selected_cookie_file ,app_base_dir ,logger ,target_domain =api_domain )
    if target_post_id :
        direct_post_api_url =f"https://{api_domain }/api/v1/{service }/user/{user_id }/post/{target_post_id }"
        logger (f"   Attempting direct fetch for target post: {direct_post_api_url }")
        try :
            direct_response =requests .get (direct_post_api_url ,headers =headers ,timeout =(10 ,30 ),cookies =cookies_for_api )
            direct_response .raise_for_status ()
            direct_post_data =direct_response .json ()
            if isinstance (direct_post_data ,list )and direct_post_data :
                direct_post_data =direct_post_data [0 ]
            if isinstance (direct_post_data ,dict )and 'post'in direct_post_data and isinstance (direct_post_data ['post'],dict ):
                 direct_post_data =direct_post_data ['post']
            if isinstance (direct_post_data ,dict )and direct_post_data .get ('id')==target_post_id :
                logger (f"   ✅ Direct fetch successful for post {target_post_id }.")
                yield [direct_post_data ]
                return 
            else :
                response_type =type (direct_post_data ).__name__ 
                response_snippet =str (direct_post_data )[:200 ]
                logger (f"   ⚠️ Direct fetch for post {target_post_id } returned unexpected data (Type: {response_type }, Snippet: '{response_snippet }'). Falling back to pagination.")
        except requests .exceptions .RequestException as e :
            logger (f"   ⚠️ Direct fetch failed for post {target_post_id }: {e }. Falling back to pagination.")
        except Exception as e :
            logger (f"   ⚠️ Unexpected error during direct fetch for post {target_post_id }: {e }. Falling back to pagination.")
    if not service or not user_id :
        logger (f"❌ Invalid URL or could not extract service/user: {api_url_input }")
        return 
    if target_post_id and (start_page or end_page ):
        logger ("⚠️ Page range (start/end page) is ignored when a specific post URL is provided (searching all pages for the post).")

    is_manga_mode_fetch_all_and_sort_oldest_first =manga_mode and (manga_filename_style_for_sort_check !=STYLE_DATE_POST_TITLE )and not target_post_id 
    api_base_url =f"https://{api_domain }/api/v1/{service }/user/{user_id }"
    page_size =50 
    if is_manga_mode_fetch_all_and_sort_oldest_first :
        logger (f"   Manga Mode (Style: {manga_filename_style_for_sort_check if manga_filename_style_for_sort_check else 'Default'} - Oldest First Sort Active): Fetching all posts to sort by date...")
        all_posts_for_manga_mode =[]
        current_offset_manga =0 
        if start_page and start_page >1 :
            current_offset_manga =(start_page -1 )*page_size 
            logger (f"   Manga Mode: Starting fetch from page {start_page } (offset {current_offset_manga }).")
        elif start_page :
            logger (f"   Manga Mode: Starting fetch from page 1 (offset 0).")
        if end_page :
            logger (f"   Manga Mode: Will fetch up to page {end_page }.")
        while True :
            if pause_event and pause_event .is_set ():
                logger ("   Manga mode post fetching paused...")
                while pause_event .is_set ():
                    if cancellation_event and cancellation_event .is_set ():
                        logger ("   Manga mode post fetching cancelled while paused.")
                        break 
                    time .sleep (0.5 )
                if not (cancellation_event and cancellation_event .is_set ()):logger ("   Manga mode post fetching resumed.")
            if cancellation_event and cancellation_event .is_set ():
                logger ("   Manga mode post fetching cancelled.")
                break 
            current_page_num_manga =(current_offset_manga //page_size )+1 
            if end_page and current_page_num_manga >end_page :
                logger (f"   Manga Mode: Reached specified end page ({end_page }). Stopping post fetch.")
                break 
            try :
                posts_batch_manga =fetch_posts_paginated (api_base_url ,headers ,current_offset_manga ,logger ,cancellation_event ,pause_event ,cookies_dict =cookies_for_api )
                if not isinstance (posts_batch_manga ,list ):
                    logger (f"❌ API Error (Manga Mode): Expected list of posts, got {type (posts_batch_manga )}.")
                    break 
                if not posts_batch_manga :
                    logger ("✅ Reached end of posts (Manga Mode fetch all).")
                    if start_page and not end_page and current_page_num_manga <start_page :
                        logger (f"   Manga Mode: No posts found on or after specified start page {start_page }.")
                    elif end_page and current_page_num_manga <=end_page and not all_posts_for_manga_mode :
                        logger (f"   Manga Mode: No posts found within the specified page range ({start_page or 1 }-{end_page }).")
                    break 
                all_posts_for_manga_mode .extend (posts_batch_manga )
                current_offset_manga +=page_size 
                time .sleep (0.6 )
            except RuntimeError as e :
                if "cancelled by user"in str (e ).lower ():
                    logger (f"ℹ️ Manga mode pagination stopped due to cancellation: {e }")
                else :
                    logger (f"❌ {e }\n   Aborting manga mode pagination.")
                break 
            except Exception as e :
                logger (f"❌ Unexpected error during manga mode fetch: {e }")
                traceback .print_exc ()
                break 
        if cancellation_event and cancellation_event .is_set ():return 
        if all_posts_for_manga_mode :
            logger (f"   Manga Mode: Fetched {len (all_posts_for_manga_mode )} total posts. Sorting by publication date (oldest first)...")
            def sort_key_tuple (post ):
                published_date_str =post .get ('published')
                added_date_str =post .get ('added')
                post_id_str =post .get ('id',"0")
                primary_sort_val ="0000-00-00T00:00:00"
                if published_date_str :
                    primary_sort_val =published_date_str 
                elif added_date_str :
                    logger (f"    ⚠️ Post ID {post_id_str } missing 'published' date, using 'added' date '{added_date_str }' for primary sorting.")
                    primary_sort_val =added_date_str 
                else :
                    logger (f"    ⚠️ Post ID {post_id_str } missing both 'published' and 'added' dates. Placing at start of sort (using default earliest date).")
                secondary_sort_val =0 
                try :
                    secondary_sort_val =int (post_id_str )
                except ValueError :
                    logger (f"    ⚠️ Post ID '{post_id_str }' is not a valid integer for secondary sorting, using 0.")
                return (primary_sort_val ,secondary_sort_val )
            all_posts_for_manga_mode .sort (key =sort_key_tuple )
            for i in range (0 ,len (all_posts_for_manga_mode ),page_size ):
                if cancellation_event and cancellation_event .is_set ():
                    logger ("   Manga mode post yielding cancelled.")
                    break 
                yield all_posts_for_manga_mode [i :i +page_size ]
        return 



    if manga_mode and not target_post_id and (manga_filename_style_for_sort_check ==STYLE_DATE_POST_TITLE ):
        logger (f"   Manga Mode (Style: {STYLE_DATE_POST_TITLE }): Processing posts in default API order (newest first).")

    current_page_num =1 
    current_offset =0 
    processed_target_post_flag =False 
    if start_page and start_page >1 and not target_post_id :
        current_offset =(start_page -1 )*page_size 
        current_page_num =start_page 
        logger (f"   Starting from page {current_page_num } (calculated offset {current_offset }).")
    while True :
        if pause_event and pause_event .is_set ():
            logger ("   Post fetching loop paused...")
            while pause_event .is_set ():
                if cancellation_event and cancellation_event .is_set ():
                    logger ("   Post fetching loop cancelled while paused.")
                    break 
                time .sleep (0.5 )
            if not (cancellation_event and cancellation_event .is_set ()):logger ("   Post fetching loop resumed.")
        if cancellation_event and cancellation_event .is_set ():
            logger ("   Post fetching loop cancelled.")
            break 
        if target_post_id and processed_target_post_flag :
            break 
        if not target_post_id and end_page and current_page_num >end_page :
            logger (f"✅ Reached specified end page ({end_page }) for creator feed. Stopping.")
            break 
        try :
            posts_batch =fetch_posts_paginated (api_base_url ,headers ,current_offset ,logger ,cancellation_event ,pause_event ,cookies_dict =cookies_for_api )
            if not isinstance (posts_batch ,list ):
                logger (f"❌ API Error: Expected list of posts, got {type (posts_batch )} at page {current_page_num } (offset {current_offset }).")
                break 
        except RuntimeError as e :
            if "cancelled by user"in str (e ).lower ():
                 logger (f"ℹ️ Pagination stopped due to cancellation: {e }")
            else :
                logger (f"❌ {e }\n   Aborting pagination at page {current_page_num } (offset {current_offset }).")
            break 
        except Exception as e :
            logger (f"❌ Unexpected error fetching page {current_page_num } (offset {current_offset }): {e }")
            traceback .print_exc ()
            break 
        if not posts_batch :
            if target_post_id and not processed_target_post_flag :
                logger (f"❌ Target post {target_post_id } not found after checking all available pages (API returned no more posts at offset {current_offset }).")
            elif not target_post_id :
                if current_page_num ==(start_page or 1 ):
                     logger (f"😕 No posts found on the first page checked (page {current_page_num }, offset {current_offset }).")
                else :
                     logger (f"✅ Reached end of posts (no more content from API at offset {current_offset }).")
            break 
        if target_post_id and not processed_target_post_flag :
            matching_post =next ((p for p in posts_batch if str (p .get ('id'))==str (target_post_id )),None )
            if matching_post :
                logger (f"🎯 Found target post {target_post_id } on page {current_page_num } (offset {current_offset }).")
                yield [matching_post ]
                processed_target_post_flag =True 
        elif not target_post_id :
            yield posts_batch 
        if processed_target_post_flag :
            break 
        current_offset +=page_size 
        current_page_num +=1 
        time .sleep (0.6 )
    if target_post_id and not processed_target_post_flag and not (cancellation_event and cancellation_event .is_set ()):
        logger (f"❌ Target post {target_post_id } could not be found after checking all relevant pages (final check after loop).")