import asyncio
import json
import logging
import uuid
from datetime import datetime

from . import order_reader, validation_service, import_service, sqlite_service
from ..config import settings

logger = logging.getLogger(__name__)

# Sync state
_sync_lock = asyncio.Lock()
_current_sync = None  # dict with run_id, status, progress info

# SSE subscriber system
_subscribers: list[asyncio.Queue] = []


def subscribe() -> asyncio.Queue:
    """Subscribe to sync events. Returns a queue that will receive event dicts."""
    q = asyncio.Queue()
    _subscribers.append(q)
    return q


def unsubscribe(q: asyncio.Queue):
    """Unsubscribe from sync events."""
    try:
        _subscribers.remove(q)
    except ValueError:
        pass


async def _emit(event: dict):
    """Push an event to all subscriber queues."""
    for q in _subscribers:
        try:
            q.put_nowait(event)
        except asyncio.QueueFull:
            pass


async def get_sync_status():
    """Get current sync status."""
    if _current_sync:
        return {**_current_sync}
    return {"status": "idle"}


async def prepare_sync(id_pol: int = None, id_sectie: int = None) -> dict:
    """Prepare a sync run - creates run_id and sets initial state.
    Returns {"run_id": ..., "status": "starting"} or {"error": ...} if already running.
    """
    global _current_sync
    if _sync_lock.locked():
        return {"error": "Sync already running", "run_id": _current_sync.get("run_id") if _current_sync else None}

    run_id = datetime.now().strftime("%Y%m%d_%H%M%S") + "_" + uuid.uuid4().hex[:6]
    _current_sync = {
        "run_id": run_id,
        "status": "running",
        "started_at": datetime.now().isoformat(),
        "progress": "Starting..."
    }
    return {"run_id": run_id, "status": "starting"}


async def run_sync(id_pol: int = None, id_sectie: int = None, run_id: str = None) -> dict:
    """Run a full sync cycle. Returns summary dict."""
    global _current_sync

    if _sync_lock.locked():
        return {"error": "Sync already running"}

    async with _sync_lock:
        # Use provided run_id or generate one
        if not run_id:
            run_id = datetime.now().strftime("%Y%m%d_%H%M%S") + "_" + uuid.uuid4().hex[:6]
            _current_sync = {
                "run_id": run_id,
                "status": "running",
                "started_at": datetime.now().isoformat(),
                "progress": "Reading JSON files..."
            }

        _current_sync["progress"] = "Reading JSON files..."
        await _emit({"type": "phase", "run_id": run_id, "message": "Reading JSON files..."})

        try:
            # Step 1: Read orders
            orders, json_count = order_reader.read_json_orders()
            await sqlite_service.create_sync_run(run_id, json_count)
            await _emit({"type": "phase", "run_id": run_id, "message": f"Found {len(orders)} orders in {json_count} files"})

            if not orders:
                await sqlite_service.update_sync_run(run_id, "completed", 0, 0, 0, 0)
                summary = {"run_id": run_id, "status": "completed", "message": "No orders found", "json_files": json_count}
                await _emit({"type": "completed", "run_id": run_id, "summary": summary})
                return summary

            _current_sync["progress"] = f"Validating {len(orders)} orders..."
            await _emit({"type": "phase", "run_id": run_id, "message": f"Validating {len(orders)} orders..."})

            # Step 2a: Find new orders (not yet in Oracle)
            all_order_numbers = [o.number for o in orders]
            new_orders = await asyncio.to_thread(
                validation_service.find_new_orders, all_order_numbers
            )

            # Step 2b: Validate SKUs (blocking Oracle call -> run in thread)
            all_skus = order_reader.get_all_skus(orders)
            validation = await asyncio.to_thread(validation_service.validate_skus, all_skus)
            importable, skipped = validation_service.classify_orders(orders, validation)

            await _emit({"type": "phase", "run_id": run_id, "message": f"{len(importable)} importable, {len(skipped)} skipped (missing SKUs)"})

            # Step 2c: Build SKU context from skipped orders
            sku_context = {}  # {sku: {"orders": [], "customers": []}}
            for order, missing_skus_list in skipped:
                customer = order.billing.company_name or \
                    f"{order.billing.firstname} {order.billing.lastname}"
                for sku in missing_skus_list:
                    if sku not in sku_context:
                        sku_context[sku] = {"orders": [], "customers": []}
                    if order.number not in sku_context[sku]["orders"]:
                        sku_context[sku]["orders"].append(order.number)
                    if customer not in sku_context[sku]["customers"]:
                        sku_context[sku]["customers"].append(customer)

            # Track missing SKUs with context
            for sku in validation["missing"]:
                product_name = ""
                for order in orders:
                    for item in order.items:
                        if item.sku == sku:
                            product_name = item.name
                            break
                    if product_name:
                        break
                ctx = sku_context.get(sku, {})
                await sqlite_service.track_missing_sku(
                    sku, product_name,
                    order_count=len(ctx.get("orders", [])),
                    order_numbers=json.dumps(ctx.get("orders", [])) if ctx.get("orders") else None,
                    customers=json.dumps(ctx.get("customers", [])) if ctx.get("customers") else None,
                )

            # Step 2d: Pre-validate prices for importable articles
            id_pol = id_pol or settings.ID_POL
            if id_pol and importable:
                _current_sync["progress"] = "Validating prices..."
                await _emit({"type": "phase", "run_id": run_id, "message": "Validating prices..."})
                # Gather all CODMATs from importable orders
                all_codmats = set()
                for order in importable:
                    for item in order.items:
                        if item.sku in validation["mapped"]:
                            # Mapped SKUs resolve to codmat via ARTICOLE_TERTI (handled by import)
                            pass
                        elif item.sku in validation["direct"]:
                            all_codmats.add(item.sku)
                # For mapped SKUs, we'd need the ARTICOLE_TERTI lookup - direct SKUs = codmat
                if all_codmats:
                    price_result = await asyncio.to_thread(
                        validation_service.validate_prices, all_codmats, id_pol
                    )
                    if price_result["missing_price"]:
                        logger.info(
                            f"Auto-adding price 0 for {len(price_result['missing_price'])} "
                            f"direct articles in policy {id_pol}"
                        )
                        await asyncio.to_thread(
                            validation_service.ensure_prices,
                            price_result["missing_price"], id_pol
                        )

            # Step 3: Record skipped orders + emit events
            for order, missing_skus in skipped:
                customer = order.billing.company_name or \
                    f"{order.billing.firstname} {order.billing.lastname}"
                await sqlite_service.add_import_order(
                    sync_run_id=run_id,
                    order_number=order.number,
                    order_date=order.date,
                    customer_name=customer,
                    status="SKIPPED",
                    missing_skus=missing_skus,
                    items_count=len(order.items)
                )
                await _emit({
                    "type": "order_result", "run_id": run_id,
                    "order_number": order.number, "customer_name": customer,
                    "status": "SKIPPED", "missing_skus": missing_skus,
                    "items_count": len(order.items), "progress": f"0/{len(importable)}"
                })

            # Step 4: Import valid orders
            imported_count = 0
            error_count = 0

            for i, order in enumerate(importable):
                progress_str = f"{i+1}/{len(importable)}"
                _current_sync["progress"] = f"Importing {progress_str}: #{order.number}"

                result = await asyncio.to_thread(
                    import_service.import_single_order,
                    order, id_pol=id_pol, id_sectie=id_sectie
                )
                customer = order.billing.company_name or \
                    f"{order.billing.firstname} {order.billing.lastname}"

                if result["success"]:
                    imported_count += 1
                    await sqlite_service.add_import_order(
                        sync_run_id=run_id,
                        order_number=order.number,
                        order_date=order.date,
                        customer_name=customer,
                        status="IMPORTED",
                        id_comanda=result["id_comanda"],
                        id_partener=result["id_partener"],
                        items_count=len(order.items)
                    )
                    await _emit({
                        "type": "order_result", "run_id": run_id,
                        "order_number": order.number, "customer_name": customer,
                        "status": "IMPORTED", "items_count": len(order.items),
                        "id_comanda": result["id_comanda"], "progress": progress_str
                    })
                else:
                    error_count += 1
                    await sqlite_service.add_import_order(
                        sync_run_id=run_id,
                        order_number=order.number,
                        order_date=order.date,
                        customer_name=customer,
                        status="ERROR",
                        id_partener=result.get("id_partener"),
                        error_message=result["error"],
                        items_count=len(order.items)
                    )
                    await _emit({
                        "type": "order_result", "run_id": run_id,
                        "order_number": order.number, "customer_name": customer,
                        "status": "ERROR", "error_message": result["error"],
                        "items_count": len(order.items), "progress": progress_str
                    })

                # Safety: stop if too many errors
                if error_count > 10:
                    logger.warning("Too many errors, stopping sync")
                    break

            # Step 5: Update sync run
            status = "completed" if error_count <= 10 else "failed"
            await sqlite_service.update_sync_run(
                run_id, status, len(orders), imported_count, len(skipped), error_count
            )

            summary = {
                "run_id": run_id,
                "status": status,
                "json_files": json_count,
                "total_orders": len(orders),
                "new_orders": len(new_orders),
                "imported": imported_count,
                "skipped": len(skipped),
                "errors": error_count,
                "missing_skus": len(validation["missing"])
            }

            logger.info(
                f"Sync {run_id} completed: {imported_count} imported, "
                f"{len(skipped)} skipped, {error_count} errors"
            )
            await _emit({"type": "completed", "run_id": run_id, "summary": summary})
            return summary

        except Exception as e:
            logger.error(f"Sync {run_id} failed: {e}")
            await sqlite_service.update_sync_run(run_id, "failed", 0, 0, 0, 1, error_message=str(e))
            _current_sync["error"] = str(e)
            await _emit({"type": "failed", "run_id": run_id, "error": str(e)})
            return {"run_id": run_id, "status": "failed", "error": str(e)}
        finally:
            # Keep _current_sync for 10 seconds so status endpoint can show final result
            async def _clear_current_sync():
                await asyncio.sleep(10)
                global _current_sync
                _current_sync = None
            asyncio.ensure_future(_clear_current_sync())


def stop_sync():
    """Signal sync to stop. Currently sync runs to completion."""
    # For now, sync runs are not cancellable mid-flight.
    # Future: use an asyncio.Event for cooperative cancellation.
    pass