"""
Annotation API router.
Provides CRUD endpoints for annotation management.
"""
import uuid
import json
from typing import List, Optional
from fastapi import APIRouter, HTTPException, status, Query
from database import get_db_connection
from schemas.annotation import AnnotationCreate, AnnotationUpdate, AnnotationResponse
from models import Annotation

router = APIRouter(
    prefix="/api/annotations",
    tags=["annotations"]
)


@router.get("", response_model=List[AnnotationResponse])
async def list_annotations(
    task_id: Optional[str] = Query(None, description="Filter by task ID"),
    user_id: Optional[str] = Query(None, description="Filter by user ID")
):
    """
    List all annotations with optional filters.
    
    Args:
        task_id: Optional task ID filter
        user_id: Optional user ID filter
    
    Returns:
        List of annotations matching the filters
    """
    with get_db_connection() as conn:
        cursor = conn.cursor()
        
        # Build query with filters
        query = """
            SELECT 
                id,
                task_id,
                user_id,
                result,
                created_at,
                updated_at
            FROM annotations
            WHERE 1=1
        """
        params = []
        
        if task_id:
            query += " AND task_id = ?"
            params.append(task_id)
        
        if user_id:
            query += " AND user_id = ?"
            params.append(user_id)
        
        query += " ORDER BY created_at DESC"
        
        cursor.execute(query, params)
        rows = cursor.fetchall()
        
        annotations = []
        for row in rows:
            # Parse JSON result
            result = json.loads(row["result"]) if isinstance(row["result"], str) else row["result"]
            
            annotations.append(AnnotationResponse(
                id=row["id"],
                task_id=row["task_id"],
                user_id=row["user_id"],
                result=result,
                created_at=row["created_at"],
                updated_at=row["updated_at"]
            ))
        
        return annotations


@router.post("", response_model=AnnotationResponse, status_code=status.HTTP_201_CREATED)
async def create_annotation(annotation: AnnotationCreate):
    """
    Create a new annotation.
    
    Args:
        annotation: Annotation creation data
    
    Returns:
        Created annotation with generated ID
    
    Raises:
        HTTPException: 404 if task not found
    """
    # Generate unique ID
    annotation_id = f"ann_{uuid.uuid4().hex[:12]}"
    
    with get_db_connection() as conn:
        cursor = conn.cursor()
        
        # Verify task exists
        cursor.execute("SELECT id FROM tasks WHERE id = ?", (annotation.task_id,))
        if not cursor.fetchone():
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Task with id '{annotation.task_id}' not found"
            )
        
        # Serialize result to JSON
        result_json = json.dumps(annotation.result)
        
        # Insert new annotation
        cursor.execute("""
            INSERT INTO annotations (id, task_id, user_id, result)
            VALUES (?, ?, ?, ?)
        """, (
            annotation_id,
            annotation.task_id,
            annotation.user_id,
            result_json
        ))
        
        # Fetch the created annotation
        cursor.execute("""
            SELECT id, task_id, user_id, result, created_at, updated_at
            FROM annotations
            WHERE id = ?
        """, (annotation_id,))
        
        row = cursor.fetchone()
        
        # Parse JSON result
        result = json.loads(row["result"]) if isinstance(row["result"], str) else row["result"]
        
        return AnnotationResponse(
            id=row["id"],
            task_id=row["task_id"],
            user_id=row["user_id"],
            result=result,
            created_at=row["created_at"],
            updated_at=row["updated_at"]
        )


@router.get("/{annotation_id}", response_model=AnnotationResponse)
async def get_annotation(annotation_id: str):
    """
    Get annotation by ID.
    
    Args:
        annotation_id: Annotation unique identifier
    
    Returns:
        Annotation details
    
    Raises:
        HTTPException: 404 if annotation not found
    """
    with get_db_connection() as conn:
        cursor = conn.cursor()
        
        # Get annotation
        cursor.execute("""
            SELECT id, task_id, user_id, result, created_at, updated_at
            FROM annotations
            WHERE id = ?
        """, (annotation_id,))
        
        row = cursor.fetchone()
        
        if not row:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Annotation with id '{annotation_id}' not found"
            )
        
        # Parse JSON result
        result = json.loads(row["result"]) if isinstance(row["result"], str) else row["result"]
        
        return AnnotationResponse(
            id=row["id"],
            task_id=row["task_id"],
            user_id=row["user_id"],
            result=result,
            created_at=row["created_at"],
            updated_at=row["updated_at"]
        )


@router.put("/{annotation_id}", response_model=AnnotationResponse)
async def update_annotation(annotation_id: str, annotation: AnnotationUpdate):
    """
    Update an existing annotation.
    
    Args:
        annotation_id: Annotation unique identifier
        annotation: Annotation update data
    
    Returns:
        Updated annotation details
    
    Raises:
        HTTPException: 404 if annotation not found
    """
    with get_db_connection() as conn:
        cursor = conn.cursor()
        
        # Check if annotation exists
        cursor.execute("SELECT id FROM annotations WHERE id = ?", (annotation_id,))
        if not cursor.fetchone():
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Annotation with id '{annotation_id}' not found"
            )
        
        # Serialize result to JSON
        result_json = json.dumps(annotation.result)
        
        # Update annotation
        cursor.execute("""
            UPDATE annotations
            SET result = ?, updated_at = CURRENT_TIMESTAMP
            WHERE id = ?
        """, (result_json, annotation_id))
        
        # Fetch and return updated annotation
        cursor.execute("""
            SELECT id, task_id, user_id, result, created_at, updated_at
            FROM annotations
            WHERE id = ?
        """, (annotation_id,))
        
        row = cursor.fetchone()
        
        # Parse JSON result
        result = json.loads(row["result"]) if isinstance(row["result"], str) else row["result"]
        
        return AnnotationResponse(
            id=row["id"],
            task_id=row["task_id"],
            user_id=row["user_id"],
            result=result,
            created_at=row["created_at"],
            updated_at=row["updated_at"]
        )


@router.get("/tasks/{task_id}/annotations", response_model=List[AnnotationResponse])
async def get_task_annotations(task_id: str):
    """
    Get all annotations for a specific task.
    
    Args:
        task_id: Task unique identifier
    
    Returns:
        List of annotations belonging to the task
    
    Raises:
        HTTPException: 404 if task not found
    """
    with get_db_connection() as conn:
        cursor = conn.cursor()
        
        # Verify task exists
        cursor.execute("SELECT id FROM tasks WHERE id = ?", (task_id,))
        if not cursor.fetchone():
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Task with id '{task_id}' not found"
            )
        
        # Get all annotations for the task
        cursor.execute("""
            SELECT id, task_id, user_id, result, created_at, updated_at
            FROM annotations
            WHERE task_id = ?
            ORDER BY created_at DESC
        """, (task_id,))
        
        rows = cursor.fetchall()
        
        annotations = []
        for row in rows:
            # Parse JSON result
            result = json.loads(row["result"]) if isinstance(row["result"], str) else row["result"]
            
            annotations.append(AnnotationResponse(
                id=row["id"],
                task_id=row["task_id"],
                user_id=row["user_id"],
                result=result,
                created_at=row["created_at"],
                updated_at=row["updated_at"]
            ))
        
        return annotations