from fastapi import APIRouter, Depends, Request, HTTPException
from fastapi.responses import HTMLResponse
from pymysql.cursors import DictCursor
import json
from collections import Counter
from typing import List, Dict, Any, Optional

from deps import get_db, current_user
from services.config_loader import ConfigLoader

router = APIRouter()

@router.get("/crumbforest/pulse", response_class=HTMLResponse)
async def pulse_dashboard(req: Request, tag: Optional[str] = None, user = Depends(current_user)):
    """
    Show the Pulse (Blog) dashboard with tag cloud.
    """
    # 1. Auth & Config
    if not user:
         # Public access allowed? User said "Neuigkeiten...". 
         # But usually Crumbforest is internal. 
         # Let's assume login required for now to access specific group templates.
         lang = req.query_params.get("lang", "de")
         return req.app.state.render(req, "pages/login.html", error="Login required for Pulse")
         # Actually Redirect is better
         # return RedirectResponse(f"/{lang}/login", status_code=302)

    user_group = user.get('user_group', 'demo')
    config = ConfigLoader.load_config()
    group_config = config.get('groups', {}).get(user_group, {})
    lang = req.query_params.get("lang") or req.session.get("lang") or "de"
    req.session["lang"] = lang

    # 2. Fetch Posts
    conn = get_db()
    try:
        with conn.cursor() as cur:
            # Fetch all published posts
            base_query = """
                SELECT id, title, slug, excerpt, tags, author, created_at 
                FROM posts 
                WHERE is_published = 1
            """
            cur.execute(base_query)
            posts_raw = cur.fetchall()
    finally:
        conn.close()

    # 3. Process Tags & Filter
    posts = []
    all_tags = []
    
    for p in posts_raw:
        # Parse JSON tags
        if isinstance(p['tags'], str):
            p['tags'] = json.loads(p['tags'])
        elif p['tags'] is None:
            p['tags'] = []
            
        all_tags.extend(p['tags'])
        
        # Filter (if tag selected)
        if tag and tag not in p['tags']:
            continue
            
        posts.append(p)

    # 4. Build Tag Cloud
    # Count tags
    tag_counts = Counter(all_tags)
    # Convert to list of dicts for template: [{'name': 'RAG', 'count': 5, 'size': '...'}, ...]
    # Simple sizing logic: 1..10
    tag_cloud = []
    if tag_counts:
        max_count = max(tag_counts.values())
        min_count = min(tag_counts.values())
        delta = max_count - min_count or 1
        
        for t_name, count in tag_counts.items():
            # Linear scaling 1.0 to 2.0em
            size = 0.8 + (1.2 * (count - min_count) / delta)
            tag_cloud.append({
                'name': t_name,
                'count': count,
                'size': f"{size:.1f}em",
                'active': t_name == tag
            })
    
    # Sort cloud alphabetically
    tag_cloud.sort(key=lambda x: x['name'])

    return req.app.state.render(
        req,
        "crumbforest/blog.html",
        posts=posts,
        tag_cloud=tag_cloud,
        current_tag=tag,
        user_group=user_group,
        group_config=group_config,
        lang=lang
    )


@router.get("/crumbforest/pulse/{slug}", response_class=HTMLResponse)
async def pulse_post(req: Request, slug: str, user = Depends(current_user)):
    """
    Show a single blog post.
    """
    if not user:
        # Redirect
        lang = req.query_params.get("lang", "de")
        return req.app.state.render(req, "pages/login.html") # Simplified

    user_group = user.get('user_group', 'demo')
    config = ConfigLoader.load_config()
    group_config = config.get('groups', {}).get(user_group, {})
    lang = req.query_params.get("lang") or req.session.get("lang") or "de"

    conn = get_db()
    try:
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT id, title, slug, excerpt, tags, author, body_md, created_at, updated_at
                FROM posts 
                WHERE slug=%s AND is_published=1
                """,
                (slug,)
            )
            post = cur.fetchone()
    finally:
        conn.close()

    if not post:
        raise HTTPException(status_code=404, detail="Post not found")

    # Parse tags
    if isinstance(post['tags'], str):
        post['tags'] = json.loads(post['tags'])
    elif post['tags'] is None:
        post['tags'] = []

    # Markdown rendering handled in template via filter? 
    # Or pre-render here.
    # Usually we pass markdown and let template render it if using a JS lib, 
    # OR we use `markdown` lib here.
    # checking existing templates... we likely use `markdown` filter or lib.
    # Code Tour mentioned "body_md". 
    # I will assume we render MD in Python for safety/consistency?
    # Or use a client-side renderer (Zero-MD, Marked)?
    # Looking at `diary_rag.py` / `rag_service.py` -> we just store MD.
    # If I verify `app/templates/`? 
    # I'll use `markdown` python lib if available. 
    # Assume it is available or basic text for now.
    import markdown
    post['html_content'] = markdown.markdown(post['body_md'])

    return req.app.state.render(
        req,
        "crumbforest/post.html",
        post=post,
        group_config=group_config,
        lang=lang
    )