"""
Inspections router.
Handles inspection lifecycle: start, SSE stream, result, issues, history, trend.

IMPORTANT: Static paths (/batch, /trend) must be registered BEFORE
dynamic paths (/{id}) to avoid routing conflicts.
"""

import json
import logging
from typing import Optional

import httpx
from fastapi import APIRouter, HTTPException, Query
from pydantic import HttpUrl, ValidationError
from sse_starlette.sse import EventSourceResponse

from app.core.database import get_db
from app.core.redis import get_redis, get_current_progress
from app.models.schemas import StartInspectionRequest, StartInspectionResponse
from app.services.inspection_service import InspectionService

logger = logging.getLogger(__name__)

router = APIRouter()


def _get_service() -> InspectionService:
    """Get InspectionService instance."""
    db = get_db()
    redis = get_redis()
    return InspectionService(db=db, redis=redis)


# ============================================================
# POST /api/inspections -- Start inspection
# ============================================================

@router.post("/inspections", status_code=202)
async def start_inspection(request: StartInspectionRequest):
    """
    Start a new web inspection.
    Returns 202 Accepted with inspection_id immediately.
    Inspection runs asynchronously in the background.
    """
    url = str(request.url)

    # Validate URL scheme
    if not url.startswith(("http://", "https://")):
        raise HTTPException(
            status_code=422,
            detail="유효한 URL을 입력해주세요 (http:// 또는 https://로 시작해야 합니다)",
        )

    service = _get_service()

    try:
        inspection_id = await service.start_inspection(
            url,
            accessibility_standard=request.accessibility_standard,
        )
    except httpx.HTTPStatusError as e:
        raise HTTPException(
            status_code=400,
            detail=f"해당 URL에 접근할 수 없습니다 (HTTP {e.response.status_code})",
        )
    except httpx.TimeoutException:
        raise HTTPException(
            status_code=400,
            detail="해당 URL에 접근할 수 없습니다 (응답 시간 초과)",
        )
    except httpx.RequestError as e:
        raise HTTPException(
            status_code=400,
            detail="해당 URL에 접근할 수 없습니다",
        )
    except Exception as e:
        logger.error("Failed to start inspection: %s", str(e))
        raise HTTPException(
            status_code=400,
            detail="해당 URL에 접근할 수 없습니다",
        )

    return StartInspectionResponse(
        inspection_id=inspection_id,
        status="running",
        url=url,
        stream_url=f"/api/inspections/{inspection_id}/stream",
    )


# ============================================================
# GET /api/inspections -- List inspections (history)
# IMPORTANT: This MUST be before /{inspection_id} routes
# ============================================================

@router.get("/inspections")
async def list_inspections(
    page: int = Query(default=1, ge=1),
    limit: int = Query(default=20, ge=1, le=100),
    url: Optional[str] = Query(default=None),
    sort: str = Query(default="-created_at"),
):
    """Get paginated inspection history."""
    service = _get_service()
    result = await service.get_inspection_list(
        page=page,
        limit=limit,
        url_filter=url,
        sort=sort,
    )
    return result


# ============================================================
# GET /api/inspections/trend -- Trend data
# IMPORTANT: Must be before /{inspection_id} to avoid conflict
# ============================================================

@router.get("/inspections/trend")
async def get_trend(
    url: str = Query(..., description="Target URL for trend data"),
    limit: int = Query(default=10, ge=1, le=50),
):
    """Get trend data (score history) for a specific URL."""
    service = _get_service()
    result = await service.get_trend(url=url, limit=limit)
    return result


# ============================================================
# GET /api/inspections/{inspection_id}/stream -- SSE stream
# ============================================================

@router.get("/inspections/{inspection_id}/stream")
async def stream_progress(inspection_id: str):
    """Stream inspection progress via Server-Sent Events."""

    async def event_generator():
        redis = get_redis()
        pubsub = redis.pubsub()
        channel = f"inspection:{inspection_id}:events"

        await pubsub.subscribe(channel)

        try:
            # Send current state immediately (client may connect mid-progress)
            current = await get_current_progress(inspection_id)
            if current:
                # Build initial progress event
                categories = {}
                for cat in ["html_css", "accessibility", "seo", "performance_security"]:
                    cat_progress = int(current.get(f"{cat}_progress", 0))
                    cat_step = current.get(f"{cat}_step", "")
                    cat_status = current.get(f"{cat}_status", "pending")
                    categories[cat] = {
                        "status": cat_status,
                        "progress": cat_progress,
                        "current_step": cat_step,
                    }

                total = sum(c["progress"] for c in categories.values())
                overall = round(total / 4)

                yield {
                    "event": "progress",
                    "data": json.dumps({
                        "inspection_id": inspection_id,
                        "status": "running",
                        "overall_progress": overall,
                        "categories": categories,
                    }, ensure_ascii=False),
                }

            # Listen for Pub/Sub messages
            async for message in pubsub.listen():
                if message["type"] == "message":
                    event_data = json.loads(message["data"])
                    event_type = event_data.pop("event_type", "progress")

                    yield {
                        "event": event_type,
                        "data": json.dumps(event_data, ensure_ascii=False),
                    }

                    # End stream on complete or error
                    if event_type in ("complete", "error"):
                        break

        except Exception as e:
            logger.error("SSE stream error for %s: %s", inspection_id, str(e))
            yield {
                "event": "error",
                "data": json.dumps({
                    "inspection_id": inspection_id,
                    "status": "error",
                    "message": "스트리밍 중 오류가 발생했습니다",
                }, ensure_ascii=False),
            }
        finally:
            await pubsub.unsubscribe(channel)
            await pubsub.aclose()

    return EventSourceResponse(
        event_generator(),
        media_type="text/event-stream",
    )


# ============================================================
# GET /api/inspections/{inspection_id} -- Get result
# ============================================================

@router.get("/inspections/{inspection_id}")
async def get_inspection(inspection_id: str):
    """Get inspection result by ID."""
    service = _get_service()
    result = await service.get_inspection(inspection_id)

    if result is None:
        raise HTTPException(
            status_code=404,
            detail="검사 결과를 찾을 수 없습니다",
        )

    # Remove MongoDB _id field if present
    result.pop("_id", None)
    return result


# ============================================================
# GET /api/inspections/{inspection_id}/issues -- Get issues
# ============================================================

@router.get("/inspections/{inspection_id}/issues")
async def get_issues(
    inspection_id: str,
    category: Optional[str] = Query(default=None),
    severity: Optional[str] = Query(default=None),
):
    """Get filtered issue list for an inspection."""
    service = _get_service()
    result = await service.get_issues(
        inspection_id=inspection_id,
        category=category,
        severity=severity,
    )

    if result is None:
        raise HTTPException(
            status_code=404,
            detail="검사 결과를 찾을 수 없습니다",
        )

    return result