"""Analysis endpoints for processing arguments, extracting topics, and predicting stance"""

from fastapi import APIRouter, HTTPException, Header, UploadFile, File, Form
from typing import Optional, List, Union
import logging
import csv
import io
import json
from datetime import datetime

from services.analysis_service import analysis_service
from models.analysis import (
    AnalysisRequest,
    AnalysisResponse,
    AnalysisResult,
    GetAnalysisRequest,
    GetAnalysisResponse,
)

router = APIRouter()
logger = logging.getLogger(__name__)


def parse_csv_file(file_content: bytes) -> List[str]:
    """
    Parse CSV file and extract arguments
    
    Args:
        file_content: CSV file content as bytes
        
    Returns:
        List of argument strings
    """
    try:
        # Decode bytes to string
        content = file_content.decode('utf-8')
        
        # Parse CSV
        csv_reader = csv.reader(io.StringIO(content))
        arguments = []
        
        # Skip header row if present, extract arguments from first column or 'argument' column
        rows = list(csv_reader)
        if len(rows) == 0:
            return []
        
        # Check if first row is header
        header = rows[0] if rows else []
        start_idx = 1 if any(col.lower() in ['argument', 'text', 'content'] for col in header) else 0
        
        # Find argument column index
        arg_col_idx = 0
        if start_idx == 1:
            for idx, col in enumerate(header):
                if col.lower() in ['argument', 'text', 'content']:
                    arg_col_idx = idx
                    break
        
        # Extract arguments
        for row in rows[start_idx:]:
            if row and len(row) > arg_col_idx:
                arg = row[arg_col_idx].strip()
                if arg:  # Only add non-empty arguments
                    arguments.append(arg)
        
        return arguments
        
    except Exception as e:
        logger.error(f"Error parsing CSV file: {str(e)}")
        raise ValueError(f"Failed to parse CSV file: {str(e)}")


@router.post("", response_model=AnalysisResponse, tags=["Analysis"])
async def analyse_arguments(
    request: AnalysisRequest,
    x_user_id: Optional[str] = Header(None, alias="X-User-ID")
):
    """
    Analyze arguments: extract topics and predict stance (JSON body)
    
    - **X-User-ID**: User UUID (required in header)
    - **arguments**: List of argument texts in JSON body
    
    Returns analysis results with extracted topics and stance predictions
    """
    if not x_user_id:
        raise HTTPException(status_code=400, detail="X-User-ID header is required")
    
    try:
        arguments = request.arguments
        logger.info(f"Received {len(arguments)} arguments from JSON body")
        
        # Analyze arguments
        results = analysis_service.analyze_arguments(
            user_id=x_user_id,
            arguments=arguments
        )
        
        # Convert to response models
        analysis_results = [
            AnalysisResult(**result) for result in results
        ]
        
        logger.info(f"Analysis completed: {len(analysis_results)} results")
        
        return AnalysisResponse(
            results=analysis_results,
            total_processed=len(analysis_results),
            timestamp=datetime.now().isoformat()
        )
        
    except HTTPException:
        raise
    except ValueError as e:
        logger.error(f"Validation error: {str(e)}")
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.error(f"Analysis error: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Analysis failed: {str(e)}")


@router.post("/csv", response_model=AnalysisResponse, tags=["Analysis"])
async def analyse_arguments_csv(
    file: UploadFile = File(...),
    x_user_id: Optional[str] = Header(None, alias="X-User-ID")
):
    """
    Analyze arguments from CSV file: extract topics and predict stance
    
    - **X-User-ID**: User UUID (required in header)
    - **file**: CSV file with arguments
    
    Returns analysis results with extracted topics and stance predictions
    """
    if not x_user_id:
        raise HTTPException(status_code=400, detail="X-User-ID header is required")
    
    try:
        # Read CSV file
        file_content = await file.read()
        arguments = parse_csv_file(file_content)
        
        if not arguments:
            raise HTTPException(
                status_code=400,
                detail="CSV file is empty or contains no valid arguments"
            )
        
        logger.info(f"Parsed {len(arguments)} arguments from CSV file")
        
        # Analyze arguments
        results = analysis_service.analyze_arguments(
            user_id=x_user_id,
            arguments=arguments
        )
        
        # Convert to response models
        analysis_results = [
            AnalysisResult(**result) for result in results
        ]
        
        logger.info(f"Analysis completed: {len(analysis_results)} results")
        
        return AnalysisResponse(
            results=analysis_results,
            total_processed=len(analysis_results),
            timestamp=datetime.now().isoformat()
        )
        
    except HTTPException:
        raise
    except ValueError as e:
        logger.error(f"Validation error: {str(e)}")
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.error(f"Analysis error: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Analysis failed: {str(e)}")


@router.get("", response_model=GetAnalysisResponse, tags=["Analysis"])
async def get_analysis_results(
    limit: int = 100,
    offset: int = 0,
    x_user_id: Optional[str] = Header(None, alias="X-User-ID")
):
    """
    Get user's analysis results
    
    - **X-User-ID**: User UUID (required in header)
    - **limit**: Maximum number of results to return (default: 100, max: 1000)
    - **offset**: Number of results to skip (default: 0)
    
    Returns paginated analysis results
    """
    if not x_user_id:
        raise HTTPException(status_code=400, detail="X-User-ID header is required")
    
    try:
        results = analysis_service.get_user_analysis_results(
            user_id=x_user_id,
            limit=limit,
            offset=offset
        )
        
        # Convert to response models
        analysis_results = [
            AnalysisResult(**result) for result in results
        ]
        
        return GetAnalysisResponse(
            results=analysis_results,
            total=len(analysis_results),
            limit=limit,
            offset=offset
        )
        
    except Exception as e:
        logger.error(f"Error getting analysis results: {str(e)}")
        raise HTTPException(status_code=500, detail=f"Failed to get analysis results: {str(e)}")