import asyncio
import html as html_mod
import json as _json
import logging
import os
import re
import secrets
import string
from contextlib import asynccontextmanager
from pathlib import Path

import mistune
from fastapi import Depends, FastAPI, HTTPException, Request, WebSocket
from fastapi.responses import FileResponse, HTMLResponse, JSONResponse, StreamingResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel, Field
from starlette.middleware.base import BaseHTTPMiddleware

from backend.collab import authenticate_websocket, collab_manager
from backend.image_processor import preprocess_images
from backend.indexer import (
    build_index,
    find_file_in_index,
    get_vault_data,
    handle_file_move,
    remove_single_file,
    update_single_file,
)
from backend.openapi_docs import (
    API_DESCRIPTION,
    TAGS_METADATA,
    enrich_openapi_schema,
    render_api_landing,
)
from backend.search import (
    init_inverted_index,
)
from backend.semantic_search import init_semantic_index
from backend.services.backups import get_backup_dir as service_get_backup_dir
from backend.services.errors import ServiceError
from backend.services.sanitizer import sanitize_html

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(name)s] %(levelname)s: %(message)s",
)
logger = logging.getLogger("obsigate")


# ---------------------------------------------------------------------------
# Pydantic response models : voir backend.schemas (vaults/history : #85 T8)
# ---------------------------------------------------------------------------


# Filesystem mutation + search / suggest / graph models : voir backend.schemas (#85 T5, T6b)

class BackupEntry(BaseModel):
    """A single backup version of a file."""
    timestamp: int = Field(description="Unix timestamp of when the backup was created")
    datetime: str = Field(description="ISO 8601 datetime string")
    size: int = Field(description="File size in bytes")
    filename: str = Field(description="Backup filename on disk")


class BackupListResponse(BaseModel):
    """Response listing all available backups for a file."""
    vault: str = Field(description="Vault name")
    path: str = Field(description="Relative file path")
    backups: list[BackupEntry] = Field(description="Available backups, newest first")


class DiffRequest(BaseModel):
    """Request parameters for generating a diff."""
    version: int = Field(description="Timestamp of the backup version to compare")
    compare_with: int | None = Field(default=None, description="Timestamp of another backup version. If omitted, compares with the current file.")


# ---------------------------------------------------------------------------
# SSE Manager — voir backend.sse (ROADMAP #85 T4, instance partagée)
# ---------------------------------------------------------------------------
# ---------------------------------------------------------------------------

from backend.search_executor import (
    get_search_executor,
    init_search_executor,
    shutdown_search_executor,
)
from backend.sse import sse_manager

# ---------------------------------------------------------------------------
# Application lifespan (replaces deprecated on_event)
# ---------------------------------------------------------------------------
from backend.watcher import VaultWatcher
from backend.watcher_state import get_watcher, set_watcher

# File watcher : handle partagé via backend.watcher_state (ROADMAP #85 T8).


async def _on_vault_change(events: list):
    """Callback invoked by VaultWatcher when files change in watched vaults.

    Processes each event (create/modify/delete/move) and updates the index
    incrementally, then broadcasts SSE notifications.
    """
    updated_vaults = set()
    changes = []

    for event in events:
        vault_name = event["vault"]
        event_type = event["type"]
        src = event["src"]
        dest = event.get("dest")

        try:
            if event_type in ("created", "modified"):
                result = await update_single_file(vault_name, src)
                if result:
                    changes.append({"action": "updated", "vault": vault_name, "path": result["path"]})
                    updated_vaults.add(vault_name)

            elif event_type == "deleted":
                result = await remove_single_file(vault_name, src)
                if result:
                    changes.append({"action": "deleted", "vault": vault_name, "path": result["path"]})
                    updated_vaults.add(vault_name)

            elif event_type == "moved":
                result = await handle_file_move(vault_name, src, dest)
                if result:
                    changes.append({"action": "moved", "vault": vault_name, "path": result["path"]})
                    updated_vaults.add(vault_name)

        except Exception as e:
            logger.error(f"Error processing {event_type} event for {src}: {e}")

    if changes:
        await sse_manager.broadcast("index_updated", {
            "vaults": list(updated_vaults),
            "changes": changes,
            "total_changes": len(changes),
        })
        logger.info(f"Hot-reload: {len(changes)} change(s) in {list(updated_vaults)}")


# ---------------------------------------------------------------------------
# Authentication bootstrap
# ---------------------------------------------------------------------------

def bootstrap_admin():
    """Create the initial admin account if no users exist.

    Reads OBSIGATE_ADMIN_USER and OBSIGATE_ADMIN_PASSWORD from environment.
    If no password is set, generates a random one and logs it ONCE.
    Only runs when auth is enabled and no users.json exists yet.
    """
    from backend.auth.middleware import is_auth_enabled
    from backend.auth.user_store import create_user, has_users

    if not is_auth_enabled():
        return

    if has_users():
        return  # Users already exist, skip

    admin_user = os.environ.get("OBSIGATE_ADMIN_USER", "admin")
    admin_pass = os.environ.get("OBSIGATE_ADMIN_PASSWORD", "")

    if not admin_pass:
        # Generate a random password and display it ONCE in logs
        admin_pass = "".join(
            secrets.choice(string.ascii_letters + string.digits)
            for _ in range(16)
        )
        logger.warning("=" * 60)
        logger.warning("PREMIER DÉMARRAGE — Compte admin créé automatiquement")
        logger.warning(f"  Utilisateur : {admin_user}")
        logger.warning(f"  Mot de passe : {admin_pass}")
        logger.warning("CHANGEZ CE MOT DE PASSE dès la première connexion !")
        logger.warning("=" * 60)

    try:
        create_user(admin_user, admin_pass, role="admin", vaults=["*"])
        logger.info(f"Admin '{admin_user}' créé avec succès")
    except PermissionError as e:
        logger.critical("=" * 60)
        logger.critical("DÉMARRAGE IMPOSSIBLE : Erreur de permission sur le dossier 'data'")
        logger.critical("L'indexation et l'authentification ne peuvent pas fonctionner.")
        logger.critical("FIX : Vérifiez les droits du volume /app/data sur l'hôte.")
        logger.critical("Exemple : sudo chown -R 1000:1000 /DOCKER_CONFIG/ObsiGate/data")
        logger.critical("=" * 60)
        raise e


# ---------------------------------------------------------------------------
# Security headers middleware
# ---------------------------------------------------------------------------

class SecurityHeadersMiddleware(BaseHTTPMiddleware):
    """Add security headers to all HTTP responses."""

    async def dispatch(self, request, call_next):
        response = await call_next(request)
        response.headers["X-Content-Type-Options"] = "nosniff"
        response.headers["X-Frame-Options"] = "SAMEORIGIN"
        response.headers["X-XSS-Protection"] = "1; mode=block"
        response.headers["Referrer-Policy"] = "strict-origin-when-cross-origin"
        # A route may set a stricter per-response policy (e.g. ``sandbox`` for
        # standalone SVG, #108-B3); keep it instead of overwriting it.
        if "Content-Security-Policy" not in response.headers:
            response.headers["Content-Security-Policy"] = (
                "default-src 'self'; "
                "script-src 'self' 'unsafe-inline' blob: https://cdnjs.cloudflare.com https://unpkg.com https://esm.sh https://cdn.jsdelivr.net https://static.cloudflareinsights.com; "
                "style-src 'self' 'unsafe-inline' https://cdnjs.cloudflare.com https://fonts.googleapis.com https://cdn.jsdelivr.net https://esm.sh; "
                "img-src 'self' data: blob:; "
                "connect-src 'self' blob: https://esm.sh https://unpkg.com https://cdnjs.cloudflare.com https://fonts.googleapis.com https://fonts.gstatic.com https://cdn.jsdelivr.net; "
                "font-src 'self' data: https://fonts.gstatic.com https://esm.sh; "
                "worker-src 'self' blob:; "
                "frame-src 'self' blob:; "
                "object-src 'none'; "
                "base-uri 'self'; "
                "form-action 'self'; "
                "frame-ancestors 'self';"
            )
        # Static assets are NOT content-hashed, so they must revalidate:
        # ``immutable``/long max-age made Cloudflare and mobile browsers serve
        # a stale build for a year (the service worker cache compounded it).
        # ``no-cache`` keeps caching but forces revalidation (ETag/Last-Modified).
        if request.url.path.startswith("/static/"):
            response.headers["Cache-Control"] = "no-cache"
        return response


def _guard_insecure_auth() -> None:
    """Warn or refuse to start when authentication is disabled (BUG-037).

    With ``OBSIGATE_AUTH_ENABLED=false`` every request is served as an
    anonymous admin. That is convenient for local use but dangerous when the
    process is reachable from a network. Binding to a non-loopback host
    without the explicit ``OBSIGATE_ALLOW_INSECURE=true`` opt-in is refused.
    """
    from backend.auth.middleware import (
        bind_host_from_argv,
        is_auth_enabled,
        is_insecure_mode_allowed,
        is_loopback_host,
    )

    if is_auth_enabled():
        return

    if is_insecure_mode_allowed():
        logger.warning(
            "Authentication is DISABLED and OBSIGATE_ALLOW_INSECURE=true: every request "
            "is treated as an anonymous administrator. Do not expose this instance."
        )
        return

    host = bind_host_from_argv()
    if not is_loopback_host(host):
        raise RuntimeError(
            "Refusing to start: authentication is disabled (OBSIGATE_AUTH_ENABLED=false) "
            f"while binding to a non-loopback address ('{host}'). This would expose an "
            "unauthenticated instance with admin access. Enable authentication, or set "
            "OBSIGATE_ALLOW_INSECURE=true if you really know what you are doing."
        )

    logger.warning(
        "Authentication is DISABLED (OBSIGATE_AUTH_ENABLED=false): every request is "
        "treated as an anonymous administrator. This is only safe on a trusted, "
        "loopback-only deployment."
    )


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan: build index on startup, cleanup on shutdown."""
    # Thread pool for offloading CPU-bound search from the event loop.
    # Sized to 2 workers so concurrent searches don't starve other requests.
    init_search_executor()

    # BUG-037: refuse to expose an unauthenticated instance on a public bind.
    _guard_insecure_auth()

    # Bootstrap admin account if needed
    bootstrap_admin()

    logger.info("ObsiGate starting — building index in background...")

    async def _progress_cb(event_type: str, data: dict):
        await sse_manager.broadcast("index_" + event_type, data)

    async def _background_startup():
        logger.info("Background indexing started")
        await build_index(_progress_cb)

        # Build inverted index in a thread pool to avoid blocking the event loop.
        # The inverted index rebuild is CPU-bound (tokenization, indexing) and
        # would freeze HTTP responses if run in the async event loop.
        loop = asyncio.get_running_loop()
        await loop.run_in_executor(get_search_executor(), init_inverted_index)
        # Build the semantic (embedding) index in the same background thread pool.
        await loop.run_in_executor(get_search_executor(), init_semantic_index)

        # BUG-040: extract the PDF text deferred during the scan now that the
        # index and inverted index are queryable (keeps startup non-blocking).
        from backend.indexer import enrich_pdf_texts
        await enrich_pdf_texts()

        # Scan for plugins in all vaults
        logger.info("Scanning for plugins...")
        from backend.indexer import vault_config
        from backend.plugins import get_plugin_registry
        registry = get_plugin_registry()
        for vault_name, cfg in vault_config.items():
            vault_path = cfg.get("path")
            if vault_path:
                try:
                    plugins = registry.scan_vault(vault_name, vault_path)
                    logger.info(f"Vault '{vault_name}': found {len(plugins)} plugin(s)")
                    from backend.plugins import emit_vault_mounted
                    emit_vault_mounted(vault_name, vault_path)
                except Exception as e:
                    logger.warning(f"Plugin scan failed for vault '{vault_name}': {e}")

        # Start file watcher (handle partagé : voir backend.watcher_state)
        config = _load_config()
        watcher_enabled = config.get("watcher_enabled", True)
        if watcher_enabled:
            use_polling = config.get("watcher_use_polling", False)
            polling_interval = config.get("watcher_polling_interval", 5.0)
            debounce = config.get("watcher_debounce", 2.0)
            watcher = VaultWatcher(
                on_file_change=_on_vault_change,
                debounce_seconds=debounce,
                use_polling=use_polling,
                polling_interval=polling_interval,
            )
            from backend.indexer import vault_config
            vaults_to_watch = {name: cfg["path"] for name, cfg in vault_config.items()}
            await watcher.start(vaults_to_watch)
            set_watcher(watcher)
            logger.info("File watcher started in background.")
        else:
            logger.info("File watcher disabled by configuration.")

        logger.info("Background startup complete.")

    asyncio.create_task(_background_startup())

    logger.info("ObsiGate ready (listening for requests while indexing).")
    yield

    # Shutdown
    await collab_manager.stop()
    watcher = get_watcher()
    if watcher:
        await watcher.stop()
        set_watcher(None)
    shutdown_search_executor()


from backend.version import get_version

app = FastAPI(
    title="ObsiGate API",
    version=get_version(),
    lifespan=lifespan,
    description=API_DESCRIPTION.strip(),
    openapi_tags=TAGS_METADATA,
    docs_url="/docs",
    redoc_url="/redoc",
    openapi_url="/openapi.json",
    contact={"name": "ObsiGate", "url": "https://git.dracodev.net/Projets/ObsiGate"},
    license_info={"name": "MIT"},
)

# Enrich the auto-generated OpenAPI 3.1 schema (#72): tags per category,
# examples, security schemes and documented error responses.
_original_openapi = app.openapi


def _custom_openapi():
    if app.openapi_schema:
        return app.openapi_schema
    schema = _original_openapi()
    app.openapi_schema = enrich_openapi_schema(schema)
    return app.openapi_schema


app.openapi = _custom_openapi  # type: ignore[method-assign]


@app.exception_handler(ServiceError)
async def _service_error_handler(request: Request, exc: ServiceError):
    """Map shared-layer domain errors to HTTP responses (``{"detail": ...}``)."""
    return JSONResponse(status_code=exc.status, content={"detail": exc.message})

# GZip compression — reduces bandwidth by ~70% for text responses
# Custom wrapper: skip compression for SSE streams (/api/events)
from fastapi.middleware.gzip import GZipMiddleware
from starlette.types import Receive, Scope, Send


class SSESafeGZipMiddleware(GZipMiddleware):
    """GZip middleware that skips SSE (Server-Sent Events) streams.

    GZip buffering breaks incremental streaming required by SSE.
    We detect SSE endpoints by path and bypass compression entirely.
    """
    # SSE endpoints that must not be buffered by GZip.
    _SSE_PATHS = (
        "/api/events",
        "/api/admin/stream",
        "/api/ai/bookslm/chat",
        "/api/ai/bookslm/agent",
        "/mcp",
    )

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
            if scope["type"] == "http" and scope.get("path") in self._SSE_PATHS:
                # Bypass GZip: passthrough directly to the inner app
                await self.app(scope, receive, send)
            else:
                await super().__call__(scope, receive, send)

app.add_middleware(SSESafeGZipMiddleware, minimum_size=1000)

# Security headers on all responses
app.add_middleware(SecurityHeadersMiddleware)

# Auth router
# Multi-format export (HTML / MD bundle / ePub) — voir backend.routers.files_media (#85 T6c).
from backend.ai_routes import router as ai_router
from backend.auth.middleware import (
    check_vault_access,
    require_admin,
    require_auth,
)
from backend.auth.router import router as auth_router
from backend.bookslm_routes import router as bookslm_router
from backend.routers.backups import router as backups_router
from backend.routers.config import _load_config
from backend.routers.config import router as config_router
from backend.routers.conflicts import router as conflicts_router
from backend.routers.files_media import router as files_media_router
from backend.routers.files_read import router as files_read_router
from backend.routers.files_write import router as files_write_router
from backend.routers.health import router as health_router
from backend.routers.history import router as history_router
from backend.routers.search import router as search_router
from backend.routers.sharing import router as sharing_router
from backend.routers.vaults import router as vaults_router
from backend.routers.webhooks import router as webhooks_router
from backend.secret_redactor import redact_file_content
from backend.skills_routes import router as skills_router

app.include_router(auth_router)
app.include_router(ai_router)
app.include_router(bookslm_router)
app.include_router(skills_router)
app.include_router(health_router)  # ROADMAP #85 T1 — System / health
app.include_router(history_router)  # ROADMAP #85 T8 — History
app.include_router(search_router)  # ROADMAP #85 T5 — Search
app.include_router(backups_router)  # ROADMAP #85 T4 — Backups
app.include_router(conflicts_router)  # ROADMAP #85 T8 — Conflicts
app.include_router(config_router)  # ROADMAP #85 T7 — Config
app.include_router(files_read_router)  # ROADMAP #85 T6a — Files read
app.include_router(files_media_router)  # ROADMAP #85 T6c — Media/export
app.include_router(files_write_router)  # ROADMAP #85 T6b — Files write
app.include_router(webhooks_router)  # ROADMAP #85 T2 — Webhooks
app.include_router(sharing_router)  # ROADMAP #85 T3 — Sharing
app.include_router(vaults_router)  # ROADMAP #85 T8 — Vaults

# Admin Dashboard endpoints (system stats, audit logs, backups, stream)
try:
    from backend.admin import router as admin_router
    app.include_router(admin_router)
    logger.info("Admin dashboard router mounted at /api/admin/*")
except ImportError as e:
    logger.warning(f"Could not load admin dashboard router: {e}")

# Push Notifications endpoints (Web Push API + VAPID)
try:
    from backend.push import router as push_router
    app.include_router(push_router)
    logger.info("Push notifications router mounted at /api/push/*")
except ImportError as e:
    logger.warning(f"Could not load push notifications router: {e}")

# Plugins system endpoints
try:
    from backend.plugins import router as plugins_router
    app.include_router(plugins_router)
    logger.info("Plugins router mounted at /api/plugins/*")
except ImportError as e:
    logger.warning(f"Could not load plugins router: {e}")

# MCP server (Streamable HTTP) for external clients (#79 phase E)
try:
    from backend.mcp.server import McpMount, mcp_app
    app.router.routes.append(McpMount(mcp_app))
    logger.info("MCP server mounted at /mcp")
except Exception as e:  # pragma: no cover - optional dependency
    logger.warning(f"Could not mount MCP server: {e}")

# Resolve frontend path relative to this file
FRONTEND_DIR = Path(__file__).resolve().parent.parent / "frontend"


# ---------------------------------------------------------------------------
# API documentation landing page (#72)
# ---------------------------------------------------------------------------

@app.get("/api", include_in_schema=False, response_class=HTMLResponse)
@app.get("/api/", include_in_schema=False, response_class=HTMLResponse)
async def api_docs_landing():
    """Human-friendly API documentation landing page (links to /docs, /redoc)."""
    return HTMLResponse(render_api_landing(get_version()))


# ---------------------------------------------------------------------------
# Path safety helper : voir backend.routers.helpers (#85 T6a, T6c)
# ---------------------------------------------------------------------------


def _resolve_safe_path(vault_root: Path, relative_path: str | None) -> Path:
    """Resolve a relative path safely within the vault root.

    Thin wrapper around the shared :func:`backend.services.paths.resolve_safe_path`
    (single implementation used by both routes and tools). The raised
    :class:`ServiceError` is mapped to an ``HTTPException`` response by the
    global exception handler in this module.

    Args:
        vault_root: The vault's root directory (absolute).
        relative_path: The user-supplied relative path.

    Returns:
        Resolved absolute ``Path``.
    """
    from backend.services.paths import resolve_safe_path as _service_resolve

    return _service_resolve(vault_root, relative_path)


def _backup_file(file_path: Path, vault_name: str, relative_path: str):
    """Create a timestamped backup of a file before modification.

    Thin wrapper around :func:`backend.services.backups.create_backup`
    (single implementation used by both routes and tools). Backups are stored
    in ``{backup_root}/{vault}/{relative_path}.{timestamp}.bak``; the operation
    is best-effort and never blocks the caller.
    """
    from backend.services.backups import create_backup

    create_backup(file_path, vault_name, relative_path)


def _check_vault_writable(vault_root: Path) -> bool:
    """Check if a vault is writable (not mounted read-only).
    
    Args:
        vault_root: The vault's root directory (absolute).
    
    Returns:
        True if the vault is writable, False otherwise.
    """
    return os.access(vault_root, os.W_OK)


# ---------------------------------------------------------------------------
# Markdown rendering helpers (singleton renderer)
# ---------------------------------------------------------------------------

import unicodedata


def _heading_slugify(text: str) -> str:
    """Generate a URL-safe slug from heading text.

    Matches the JavaScript slugify algorithm exactly using
    Unicode-aware character classification:
    1. Strip HTML tags (e.g. wikilink spans rendered inside headings)
    2. Decode HTML entities (e.g. ``&`` → ``&``)
    3. Lowercase
    4. NFD normalize + strip combining marks
    5. Keep only Unicode letters, numbers, spaces, hyphens
    6. Replace spaces with hyphens, collapse multiple hyphens

    Args:
        text: The heading text content (may contain inline HTML).

    Returns:
        A URL-safe slug string.
    """
    # Strip any inline HTML so it does not pollute the slug
    text = re.sub(r"<[^>]+>", "", text)
    # Decode HTML entities so &amp; becomes & before slugification
    text = html_mod.unescape(text)
    text = text.lower()
    text = unicodedata.normalize("NFD", text)
    text = "".join(ch for ch in text if not unicodedata.combining(ch))
    # Unicode-aware: keep letters (L*), numbers (N*), spaces, and hyphens
    cleaned = []
    for ch in text:
        cat = unicodedata.category(ch)
        if cat.startswith('L') or cat.startswith('N') or ch in (' ', '-'):
            cleaned.append(ch)
    text = "".join(cleaned)
    text = re.sub(r"\s+", "-", text)
    text = re.sub(r"-+", "-", text)
    result = text.strip("-")
    return result if result else "heading"


def _add_heading_ids(html: str) -> str:
    """Post-process rendered HTML to add IDs to heading tags.

    Adds an ``id`` attribute to every ``<h1>`` through ``<h6>`` tag
    using a slug generated from the heading's text content.
    Duplicate slugs get a ``-2``, ``-3``, etc. suffix.

    Args:
        html: Rendered HTML string.

    Returns:
        HTML with heading IDs injected.
    """
    used_ids: dict[str, int] = {}

    def _replace_heading(match):
        tag = match.group(1)
        content = match.group(2)
        slug = _heading_slugify(content)
        count = used_ids.get(slug, 0)
        used_ids[slug] = count + 1
        if count > 0:
            slug = f"{slug}-{count + 1}"
        return f'<{tag} id="{slug}">{content}</{tag}>'

    # Match h1-h6 tags with text content (no existing id attribute)
    return re.sub(
        r'<(h[1-6])>([^<]*(?:<(?!/?h[1-6])[^<]*)*)</h[1-6]>',
        _replace_heading,
        html,
    )


# Cached mistune renderer — avoids re-creating on every request
_markdown_renderer = mistune.create_markdown(
    escape=False,
    plugins=["table", "strikethrough", "footnotes", "task_lists"],
)


def _convert_wikilinks(content: str, current_vault: str) -> str:
    """Convert ``[[wikilinks]]`` and ``[[target|display]]`` to clickable HTML.

    Supports:
    - Internal file links: ``[[My Note]]`` / ``[[My Note|display]]``
    - Same-document anchors: ``[[#Heading]]`` / ``[[#Heading|display]]``

    Resolved file links get a ``data-vault`` / ``data-path`` attribute pair.
    Anchor links target the slugified heading ID in the current document.
    Unresolved links are rendered as ``<span class="wikilink-missing">``.

    Args:
        content: Markdown string potentially containing wikilinks.
        current_vault: Active vault name for resolution priority.

    Returns:
        Markdown string with wikilinks replaced by HTML anchors.
    """
    def _replace(match):
        target = match.group(1).strip()
        display = match.group(2).strip() if match.group(2) else target

        # Same-document anchor link: [[#Heading|display]]
        if target.startswith("#"):
            anchor_text = target[1:].strip()
            anchor_slug = _heading_slugify(anchor_text)
            link_display = display if display != target else anchor_text
            return f'<a class="wikilink-anchor" href="#{anchor_slug}">{link_display}</a>'

        found = find_file_in_index(target, current_vault)
        if found:
            return (
                f'<a class="wikilink" href="#" '
                f'data-vault="{found["vault"]}" '
                f'data-path="{found["path"]}">{display}</a>'
            )
        return f'<span class="wikilink-missing">{display}</span>'

    pattern = r'\[\[([^\]|]+)(?:\|([^\]]+))?\]\]'
    return re.sub(pattern, _replace, content)


def _normalize_line_breaks(text: str) -> str:
    """Convert single newlines to hard breaks (matching Obsidian default behavior).

    In standard Markdown, a single ``\\n`` is a "soft break" — it renders as a space,
    not a visible line break.  Obsidian defaults to treating single newlines as hard
    breaks (equivalent to ``<br>``).  This function pre-processes the Markdown source
    so that mistune renders standalone lines on separate rows, while still honouring
    blank lines as paragraph separators.

    Fenced code blocks (`` ``` ``) are left untouched so their internal newlines are
    preserved verbatim.
    """
    parts = re.split(r"(```[\s\S]*?```)", text)
    for i, part in enumerate(parts):
        if part.startswith("```"):
            continue  # Protect fenced code blocks
        # Single \n (not preceded or followed by another \n) → two spaces + \n
        parts[i] = re.sub(r"(?<!\n)\n(?!\n)", "  \n", part)
    return "".join(parts)


def _render_markdown(raw_md: str, vault_name: str, current_file_path: Path | None = None) -> str:
    """Render a markdown string to HTML with wikilink and image support.

    Uses the cached singleton mistune renderer for performance.

    Args:
        raw_md: Raw markdown text (frontmatter already stripped).
        vault_name: Current vault for wikilink resolution context.
        current_file_path: Absolute path to the current markdown file.

    Returns:
        HTML string.
    """
    # Get vault data for image resolution
    vault_data = get_vault_data(vault_name)
    vault_root = Path(vault_data["path"]) if vault_data else None
    attachments_path = vault_data.get("config", {}).get("attachmentsPath") if vault_data else None

    # Redact secrets before rendering (P0 security)
    raw_md = redact_file_content(raw_md, str(current_file_path) if current_file_path else "")

    # Preprocess images first
    if vault_root:
        raw_md = preprocess_images(raw_md, vault_name, vault_root, current_file_path, attachments_path)
    
    # Convert wikilinks
    converted = _convert_wikilinks(raw_md, vault_name)
    
    # Normalize line breaks to match Obsidian behavior (single \n → hard break)
    converted = _normalize_line_breaks(converted)
    
    rendered = _markdown_renderer(converted)
    
    # Add heading IDs for TOC navigation
    rendered = _add_heading_ids(rendered)

    # Sanitize: raw HTML in vault content must never reach the DOM (BUG-021).
    rendered = sanitize_html(rendered)

    return rendered


# ---------------------------------------------------------------------------
# API Endpoints — System / health : voir backend.routers.health (#85 T1)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Vaults : voir backend.routers.vaults (#85 T8)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# History (recent / bookmarks / saved-searches) : voir backend.routers.history (#85 T8)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# File browse & read endpoints : voir backend.routers.files_read (#85 T6a)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# File PDF / export / guide / media endpoints : voir backend.routers.files_media (#85 T6c)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# File & directory mutations : voir backend.routers.files_write (#85 T6b)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# File creation and rename endpoints : voir backend.routers.files_write (#85 T6b)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# File creation and rename endpoints : voir backend.routers.files_write (#85 T6b)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Backup & Diff endpoints
# ---------------------------------------------------------------------------

def _get_backup_dir(vault_name: str, relative_path: str) -> Path:
    """Return the directory where backups for a specific file are stored.

    Thin wrapper around :func:`backend.services.backups.get_backup_dir`
    (single implementation used by both routes and tools).
    """
    return service_get_backup_dir(vault_name, relative_path)


# ---------------------------------------------------------------------------
# File-level backup endpoints : voir backend.routers.backups (#85 T4)
# ---------------------------------------------------------------------------

# File backlinks + view endpoints : voir backend.routers.files_read (#85 T6a)


# Range helper : voir backend.routers.helpers.stream_file_with_range (#85 T6c)

# PDF stream/info endpoints : voir backend.routers.files_media (#85 T6c)


# ---------------------------------------------------------------------------
# Search / suggest / graph / index-reload : voir backend.routers.search (#85 T5)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# SSE endpoint — Server-Sent Events stream
# ---------------------------------------------------------------------------

@app.get(
    "/api/events",
    response_class=StreamingResponse,
    responses={200: {"content": {"text/event-stream": {}}, "description": "Server-Sent Events stream"}},
)
async def api_events(current_user=Depends(require_auth)):
    """SSE stream for real-time index update notifications.

    Sends keepalive comments every 30s. Events:
    - ``index_updated``: partial index change (file create/modify/delete/move)
    - ``index_reloaded``: full re-index completed
    - ``vault_added``: new vault added dynamically
    - ``vault_removed``: vault removed dynamically
    """
    queue = await sse_manager.connect()

    async def event_generator():
        try:
            # Send initial connection event
            yield f"event: connected\ndata: {_json.dumps({'sse_clients': sse_manager.client_count})}\n\n"
            while True:
                try:
                    msg = await asyncio.wait_for(queue.get(), timeout=30.0)
                    yield f"event: {msg['event']}\ndata: {msg['data']}\n\n"
                except asyncio.TimeoutError:
                    # Keepalive comment
                    yield ": keepalive\n\n"
                except asyncio.CancelledError:
                    break
        finally:
            sse_manager.disconnect(queue)

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no",
        },
    )


# ---------------------------------------------------------------------------
# Dynamic vault management endpoints : voir backend.routers.vaults (#85 T8)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Image / media / attachments / vault-settings : voir backend.routers.files_media (#85 T6c)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Vault Settings API — Display preferences : voir backend.routers.files_media (#85 T6c)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Backup Management API
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Global backup endpoints : voir backend.routers.backups (#85 T4)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Configuration API : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# AI API Keys : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Tool & connected-source keys (#103) : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# AI Models : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# AI Models : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Diagnostics API : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Dashboard endpoint (aggregated stats) : voir backend.routers.config (#85 T7)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Webhook CRUD endpoints : voir backend.routers.webhooks (#85 T2)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Share (public document) endpoints : voir backend.routers.sharing (#85 T3)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Syncthing conflict endpoints : voir backend.routers.conflicts (#85 T8)
# ---------------------------------------------------------------------------


# ---------------------------------------------------------------------------
# Real-time collaboration — WebSocket endpoint (ROADMAP #62)
# ---------------------------------------------------------------------------

@app.websocket("/ws/collab/{vault_name}/{path:path}")
async def collab_websocket(websocket: WebSocket, vault_name: str, path: str):
    """Real-time collaborative editing over WebSocket (ROADMAP #62).

    One *room* is created per ``vault::path``; all clients editing the same
    file share Yjs/CRDT updates, awareness (cursors/selection) and a debounced
    server-side persistence of the markdown content.

    Authentication is performed manually (FastAPI ``Depends`` do not run for
    WebSocket routes) and vault access is enforced per connection.
    """
    from backend.services.errors import ServiceError
    from backend.services.vaults import get_vault_root

    user = authenticate_websocket(websocket)
    if user is None:
        await websocket.close(code=4401)
        return

    if not check_vault_access(vault_name, user):
        await websocket.close(code=4403)
        return

    try:
        vault_root = get_vault_root(vault_name)
        file_path = _resolve_safe_path(vault_root, path)
    except ServiceError:
        await websocket.close(code=4404)
        return

    if not file_path.exists() or not file_path.is_file():
        await websocket.close(code=4404)
        return

    await websocket.accept()
    await collab_manager.connect(websocket, vault_name, path, file_path, user)


# ---------------------------------------------------------------------------
# Static files & SPA fallback
# ---------------------------------------------------------------------------

if FRONTEND_DIR.exists():
    # ``Cache-Control`` for /static is set by SecurityHeadersMiddleware (no-cache).
    app.mount("/static", StaticFiles(directory=str(FRONTEND_DIR)), name="static")

    @app.get("/sw.js")
    async def serve_service_worker():
        """Serve the service worker for PWA support."""
        sw_file = FRONTEND_DIR / "sw.js"
        if sw_file.exists():
            return FileResponse(
                sw_file,
                media_type="application/javascript",
                headers={
                    "Cache-Control": "no-cache, no-store, must-revalidate",
                    "Service-Worker-Allowed": "/"
                }
            )
        raise HTTPException(status_code=404, detail="Service worker not found")

    @app.get("/manifest.json")
    async def serve_manifest():
        """Serve the PWA manifest."""
        manifest_file = FRONTEND_DIR / "manifest.json"
        if manifest_file.exists():
            return FileResponse(
                manifest_file,
                media_type="application/manifest+json",
                headers={"Cache-Control": "no-cache"}
            )
        raise HTTPException(status_code=404, detail="Manifest not found")

    @app.get("/popout/{vault_name}/{path:path}")
    async def serve_popout(vault_name: str, path: str):
        """Serve the minimalist popout page for a specific file."""
        popout_file = FRONTEND_DIR / "popout.html"
        if popout_file.exists():
            return HTMLResponse(content=popout_file.read_text(encoding="utf-8"), headers={"Cache-Control": "no-cache"})
        raise HTTPException(status_code=404, detail="Popout template not found")

    @app.get("/editor-poc")
    async def serve_editor_poc():
        """Serve the standalone Editor POC page (multi-zone toolbar demo)."""
        poc_file = FRONTEND_DIR / "editor-poc.html"
        if poc_file.exists():
            return HTMLResponse(content=poc_file.read_text(encoding="utf-8"), headers={"Cache-Control": "no-cache"})
        raise HTTPException(status_code=404, detail="Editor POC not found")

    @app.get("/admin.html", response_class=HTMLResponse)
    async def serve_admin_page(_current_user=Depends(require_admin)):
        """Serve the admin dashboard page (ROADMAP #71) — admin-gated.

        Must be declared BEFORE the SPA catch-all ``/{full_path:path}`` or the
        admin page would be shadowed by ``index.html`` (the reported bug: the
        Admin menu kept returning to the main page).
        """
        admin_file = FRONTEND_DIR / "admin.html"
        if admin_file.exists():
            return HTMLResponse(content=admin_file.read_text(encoding="utf-8"), headers={"Cache-Control": "no-cache"})
        raise HTTPException(status_code=404, detail="Admin page not found")

    @app.get("/{full_path:path}")
    async def serve_spa(full_path: str):
        """Serve the SPA index.html for all non-API routes."""
        index_file = FRONTEND_DIR / "index.html"
        if index_file.exists():
            return HTMLResponse(content=index_file.read_text(encoding="utf-8"), headers={"Cache-Control": "no-cache"})
        raise HTTPException(status_code=404, detail="Frontend not found")