"""FastAPI application - LeoCRM backend."""

from __future__ import annotations

import time
import traceback
from contextlib import asynccontextmanager

from fastapi import FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles
from starlette.middleware.base import BaseHTTPMiddleware
import os

from app.config import get_settings
from app.core.db import close_engine, get_engine
from app.core.middleware import CSRFMiddleware
from app.core.monitoring import record_error, record_request
from app.core.service_container import get_container
from app.plugins.registry import get_registry
from app.routes import (
    ai_copilot,
    auth,
    companies,
    contacts,
    health,
    import_export,
    metrics,
    notifications,
    plugins,
    roles,
    tenants,
    users,
    workflows,
)


class RequestLoggingMiddleware(BaseHTTPMiddleware):
    """Structured logging + Prometheus metrics for every HTTP request."""

    async def dispatch(self, request: Request, call_next):
        start_time = time.perf_counter()
        method = request.method
        path = request.url.path

        # Extract tenant_id from session cookie if available (best-effort)
        tenant_id = None

        try:
            response = await call_next(request)
        except Exception as exc:
            duration_ms = (time.perf_counter() - start_time) * 1000
            tb_str = traceback.format_exc()
            record_error(
                event="unhandled_exception",
                method=method,
                path=path,
                status_code=500,
                error=str(exc),
                traceback_str=tb_str,
                tenant_id=tenant_id,
            )
            raise

        duration_ms = (time.perf_counter() - start_time) * 1000
        status_code = response.status_code

        # Try to get tenant_id from response headers or request state
        # (set by auth middleware/dependency — best-effort, never log credentials)
        record_request(
            method=method,
            path=path,
            status_code=status_code,
            duration_ms=duration_ms,
            tenant_id=tenant_id,
        )

        return response


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan: startup and shutdown."""
    # Initialize service container
    container = get_container()
    await container.initialize()

    # Initialize plugin registry and discover built-in plugins
    registry = get_registry()
    registry.initialize(get_engine(), app)
    registry.discover_builtins()

    yield

    await close_engine()


def create_app() -> FastAPI:
    """Create and configure the FastAPI application."""
    settings = get_settings()
    app = FastAPI(title="LeoCRM", version="1.0.0", lifespan=lifespan)

    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.cors_origin_list,
        allow_credentials=True,
        allow_methods=["GET", "POST", "PATCH", "PUT", "DELETE", "OPTIONS"],
        allow_headers=["Authorization", "Content-Type", "X-CSRF-Token", "X-Tenant-ID"],
        max_age=3600,
    )
    app.add_middleware(CSRFMiddleware)
    app.add_middleware(RequestLoggingMiddleware)

    app.include_router(health.router)
    app.include_router(metrics.router)
    app.include_router(auth.router)
    app.include_router(users.router)
    app.include_router(roles.router)
    app.include_router(tenants.router)
    app.include_router(notifications.router)
    app.include_router(companies.router)
    app.include_router(contacts.router)
    app.include_router(import_export.router)
    app.include_router(plugins.router)
    app.include_router(ai_copilot.router)
    app.include_router(workflows.router)

    # ─── Serve frontend static files (SPA) ───────────────────────────────
    # Mount built frontend assets (JS, CSS, images)
    frontend_dist = os.path.join(os.path.dirname(__file__), "..", "frontend", "dist")
    if os.path.isdir(frontend_dist):
        # Serve static assets at /assets
        assets_path = os.path.join(frontend_dist, "assets")
        if os.path.isdir(assets_path):
            app.mount("/assets", StaticFiles(directory=assets_path), name="assets")

        # SPA catch-all: serve index.html for all non-API routes
        @app.get("/{full_path:path}")
        async def spa_spa(full_path: str):
            """Serve index.html for all non-API routes (SPA fallback)."""
            # Don't intercept API routes
            if full_path.startswith(("api/", "docs", "openapi", "redoc")):
                raise HTTPException(status_code=404, detail="Not Found")
            index_path = os.path.join(frontend_dist, "index.html")
            if os.path.isfile(index_path):
                return FileResponse(index_path)
            raise HTTPException(status_code=404, detail="Frontend not built")

    return app


app = create_app()