import os
import markdown
from fastapi import APIRouter, Request, HTTPException, Depends
from fastapi.responses import HTMLResponse

from deps import current_user

router = APIRouter()

# Whitelist allowed files. 
# We look for them in the root directory relative to 'app' parent.
# Since app is in /app inside docker, the root volume mount is usually at /app or mapped.
# Code Tour Step 828 shows 'app/main.py' path analysis.
# If workdir is /app (docker), and files are in /app (root of repo mapped to /app), then "README.md" is at "./README.md".

ALLOWED_DOCS = {
    "README.md": "Start Guide (Readme)",
    "QUICKSTART.md": "Schnellstart",
    "HANDBUCH.md": "Benutzerhandbuch",
    "CODE_TOUR.md": "Code Tour (Dev)",
    "ARCHITECTURE_ROLES_GROUPS.md": "Architektur",
    "DIARY_RAG_README.md": "Tagebuch & RAG Info",
    "CrumbTech.md": "Technische Details",
    "QDRANT_ACCESS.md": "Vektor DB Access",
    "docs_git.md": "Guide - Git & Versionierung",
    "deploy_security_fixes.sh": "Security Script (Source)" # Maybe viewing scripts is cool too? Let's stick to MD for now.
}

from config import get_settings


@router.get("/docs", response_class=HTMLResponse)
async def list_docs(req: Request):
    """
    List available documentation files dynamically.
    """
    base_path = _get_docs_base_path()
    
    # 1. Pinned Docs (from whitelist)
    pinned = []
    pinned_paths = set()

    for filename, title in ALLOWED_DOCS.items():
        # Check root level only for pinned items (simpler, or check recursively and pin first?)
        # Legacy behavior was pinned items are usually in root.
        # Let's verify existence.
        full_path = _find_file_recursive(base_path, filename)
        if full_path:
            # We want the relative path as the ID
            rel_path = os.path.relpath(full_path, base_path)
            pinned.append({"name": title, "file": rel_path})
            pinned_paths.add(rel_path)

    # 2. All other docs (dynamic scan)
    library = []
    
    if os.path.exists(base_path):
        for root, dirs, files in os.walk(base_path):
            for file in files:
                if file.endswith(".md"):
                    full_path = os.path.join(root, file)
                    rel_path = os.path.relpath(full_path, base_path)
                    
                    if rel_path not in pinned_paths:
                        # Improved Naming: File name + Parent Dir if nested
                        # e.g. crumbcodex/README.md -> "Crumbcodex / Readme"
                        parent = os.path.basename(root)
                        safe_name = file.replace(".md", "").replace("-", " ").title()
                        
                        if parent and parent != os.path.basename(base_path) and parent != "docs": 
                            # If deeper than root
                            display_name = f"{parent.title()} / {safe_name}"
                        else:
                            display_name = safe_name
                            
                        library.append({"name": display_name, "file": rel_path})

    # Combine
    all_docs = pinned + sorted(library, key=lambda x: x["name"])

    return req.app.state.render(
        req,
        "pages/docs_index.html",
        docs=all_docs,
        page_title="Dokumentation"
    )

@router.get("/docs/{file_path:path}", response_class=HTMLResponse)
async def view_doc(req: Request, file_path: str):
    """
    Render a specific markdown file. specific via relative path.
    """
    # Security: Prevent traversal up
    if ".." in file_path:
        raise HTTPException(400, "Invalid path.")

    base_path = _get_docs_base_path()
    full_path = os.path.join(base_path, file_path)
    
    if not os.path.exists(full_path) or not os.path.isfile(full_path):
        # Fallback: maybe it was a legacy link with just filename?
        # Try finding it recursively if direct path fails
        found = _find_file_recursive(base_path, os.path.basename(file_path))
        if found:
            full_path = found
        else:
            raise HTTPException(404, "File not on server.")
        
    try:
        with open(full_path, "r", encoding="utf-8") as f:
            content = f.read()
            
        html_content = markdown.markdown(
            content, 
            extensions=['tables', 'fenced_code', 'nl2br']
        )
        
        # Determine Title
        filename = os.path.basename(full_path)
        # Check if pinned to get nice title
        title = filename.replace(".md", "").replace("-", " ").title()
        for k, v in ALLOWED_DOCS.items():
            if k == filename:
                title = v
                break
        
        return req.app.state.render(
            req,
            "pages/doc_viewer.html",
            doc_title=title,
            doc_content=html_content,
            filename=file_path # Keep full path for context? Or filename? Template uses it for back link maybe?
        )
        
    except Exception as e:
        raise HTTPException(500, f"Error rendering document: {e}")

def _get_docs_base_path():
    try:
        settings = get_settings()
        base_path = settings.docs_path
    except:
        base_path = "docs"
        
    if not os.path.isabs(base_path) and not os.path.exists(base_path):
         if os.path.exists("/docs_root"):
            base_path = "/docs_root"
         else:
            base_path = "."
    return base_path

def _find_file(base_path, filename):
    """Legacy helper: find in base or level 1 subdirs."""
    return _find_file_recursive(base_path, filename)

def _find_file_recursive(base_path, filename):
    """Find file recursively in base_path."""
    # 1. Direct check
    direct = os.path.join(base_path, filename)
    if os.path.exists(direct) and os.path.isfile(direct):
        return direct
        
    # 2. Walk
    for root, dirs, files in os.walk(base_path):
        if filename in files:
            return os.path.join(root, filename)
            
    return None