"""
Email Management Router
API endpoints for email viewing, classification, and rule management
"""

import logging
from fastapi import APIRouter, HTTPException, Query
from typing import List, Optional
from pydantic import BaseModel
from datetime import datetime, date

from app.core.database import execute_query, execute_insert
from app.services.email_processor_service import EmailProcessorService

logger = logging.getLogger(__name__)

router = APIRouter()


# Pydantic Models
class EmailListItem(BaseModel):
    id: int
    message_id: str
    subject: str
    sender_email: str
    sender_name: Optional[str]
    received_date: datetime
    classification: Optional[str]
    confidence_score: Optional[float]
    status: str
    is_read: bool
    has_attachments: bool
    attachment_count: int
    rule_name: Optional[str] = None
    supplier_name: Optional[str] = None
    customer_name: Optional[str] = None


class EmailDetail(BaseModel):
    id: int
    message_id: str
    subject: str
    sender_email: str
    sender_name: Optional[str]
    recipient_email: Optional[str]
    cc: Optional[str]
    body_text: Optional[str]
    body_html: Optional[str]
    received_date: datetime
    folder: str
    classification: Optional[str]
    confidence_score: Optional[float]
    status: str
    is_read: bool
    has_attachments: bool
    attachment_count: int
    rule_id: Optional[int]
    supplier_id: Optional[int]
    customer_id: Optional[int]
    linked_case_id: Optional[int]
    extracted_invoice_number: Optional[str]
    extracted_amount: Optional[float]
    extracted_due_date: Optional[date]
    auto_processed: bool
    created_at: datetime
    updated_at: datetime


class EmailRule(BaseModel):
    id: Optional[int] = None
    name: str
    description: Optional[str]
    conditions: dict
    action_type: str
    action_params: Optional[dict] = {}
    priority: int = 100
    enabled: bool = True
    match_count: int = 0
    last_matched_at: Optional[datetime]


class ProcessingStats(BaseModel):
    status: str
    fetched: int = 0
    saved: int = 0
    classified: int = 0
    rules_matched: int = 0
    errors: int = 0


# Email Endpoints
@router.get("/emails", response_model=List[EmailListItem])
async def list_emails(
    status: Optional[str] = Query(None),
    classification: Optional[str] = Query(None),
    limit: int = Query(50, le=500),
    offset: int = Query(0, ge=0)
):
    """Get list of emails with filtering"""
    try:
        where_clauses = ["em.deleted_at IS NULL"]
        params = []
        
        if status:
            where_clauses.append("em.status = %s")
            params.append(status)
        
        if classification:
            where_clauses.append("em.classification = %s")
            params.append(classification)
        
        where_sql = " AND ".join(where_clauses)
        
        query = f"""
            SELECT 
                em.id, em.message_id, em.subject, em.sender_email, em.sender_name,
                em.received_date, em.classification, em.confidence_score, em.status,
                em.is_read, em.has_attachments, em.attachment_count,
                er.name as rule_name,
                v.name as supplier_name,
                NULL as customer_name
            FROM email_messages em
            LEFT JOIN email_rules er ON em.rule_id = er.id
            LEFT JOIN vendors v ON em.supplier_id = v.id
            WHERE {where_sql}
            ORDER BY em.received_date DESC
            LIMIT %s OFFSET %s
        """
        
        params.extend([limit, offset])
        result = execute_query(query, tuple(params))
        
        return result
    
    except Exception as e:
        logger.error(f"❌ Error listing emails: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.get("/emails/{email_id}", response_model=EmailDetail)
async def get_email(email_id: int):
    """Get email detail by ID"""
    try:
        query = """
            SELECT * FROM email_messages 
            WHERE id = %s AND deleted_at IS NULL
        """
        result = execute_query(query, (email_id,))
        
        if not result:
            raise HTTPException(status_code=404, detail="Email not found")
        
        # Mark as read
        update_query = "UPDATE email_messages SET is_read = true WHERE id = %s"
        execute_query(update_query, (email_id,))
        
        return result[0]
    
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"❌ Error getting email {email_id}: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/emails/process")
async def process_emails():
    """Manually trigger email processing"""
    try:
        processor = EmailProcessorService()
        stats = await processor.process_inbox()
        
        return {
            "success": True,
            "message": "Email processing completed",
            "stats": stats
        }
    
    except Exception as e:
        logger.error(f"❌ Email processing failed: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/emails/{email_id}/reprocess")
async def reprocess_email(email_id: int):
    """Manually reprocess a single email (reclassify + rematch rules)"""
    try:
        processor = EmailProcessorService()
        await processor.reprocess_email(email_id)
        
        return {
            "success": True,
            "message": f"Email {email_id} reprocessed successfully"
        }
    
    except Exception as e:
        logger.error(f"❌ Error reprocessing email {email_id}: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.put("/emails/{email_id}/classify")
async def update_classification(email_id: int, classification: str):
    """Manually update email classification"""
    try:
        valid_classifications = [
            'invoice', 'freight_note', 'order_confirmation', 'time_confirmation',
            'case_notification', 'customer_email', 'bankruptcy', 'general', 'spam', 'unknown'
        ]
        
        if classification not in valid_classifications:
            raise HTTPException(status_code=400, detail=f"Invalid classification. Must be one of: {valid_classifications}")
        
        query = """
            UPDATE email_messages 
            SET classification = %s, 
                classification_date = CURRENT_TIMESTAMP
            WHERE id = %s AND deleted_at IS NULL
        """
        execute_query(query, (classification, email_id))
        
        return {
            "success": True,
            "message": f"Email {email_id} classified as '{classification}'"
        }
    
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"❌ Error updating classification: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/emails/{email_id}")
async def delete_email(email_id: int):
    """Soft delete email"""
    try:
        query = """
            UPDATE email_messages 
            SET deleted_at = CURRENT_TIMESTAMP
            WHERE id = %s
        """
        execute_query(query, (email_id,))
        
        return {
            "success": True,
            "message": f"Email {email_id} deleted"
        }
    
    except Exception as e:
        logger.error(f"❌ Error deleting email: {e}")
        raise HTTPException(status_code=500, detail=str(e))


# Email Rules Endpoints
@router.get("/email-rules", response_model=List[EmailRule])
async def list_rules():
    """Get all email rules"""
    try:
        query = """
            SELECT * FROM email_rules 
            ORDER BY priority ASC, name ASC
        """
        result = execute_query(query)
        return result
    
    except Exception as e:
        logger.error(f"❌ Error listing rules: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/email-rules", response_model=EmailRule)
async def create_rule(rule: EmailRule):
    """Create new email rule"""
    try:
        query = """
            INSERT INTO email_rules 
            (name, description, conditions, action_type, action_params, priority, enabled, created_by_user_id)
            VALUES (%s, %s, %s, %s, %s, %s, %s, 1)
            RETURNING *
        """
        
        import json
        result = execute_query(query, (
            rule.name,
            rule.description,
            json.dumps(rule.conditions),
            rule.action_type,
            json.dumps(rule.action_params or {}),
            rule.priority,
            rule.enabled
        ))
        
        if result:
            logger.info(f"✅ Created email rule: {rule.name}")
            return result[0]
        else:
            raise HTTPException(status_code=500, detail="Failed to create rule")
    
    except Exception as e:
        logger.error(f"❌ Error creating rule: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.put("/email-rules/{rule_id}", response_model=EmailRule)
async def update_rule(rule_id: int, rule: EmailRule):
    """Update existing email rule"""
    try:
        import json
        query = """
            UPDATE email_rules 
            SET name = %s, 
                description = %s, 
                conditions = %s, 
                action_type = %s, 
                action_params = %s, 
                priority = %s, 
                enabled = %s
            WHERE id = %s
            RETURNING *
        """
        
        result = execute_query(query, (
            rule.name,
            rule.description,
            json.dumps(rule.conditions),
            rule.action_type,
            json.dumps(rule.action_params or {}),
            rule.priority,
            rule.enabled,
            rule_id
        ))
        
        if result:
            logger.info(f"✅ Updated email rule {rule_id}")
            return result[0]
        else:
            raise HTTPException(status_code=404, detail="Rule not found")
    
    except Exception as e:
        logger.error(f"❌ Error updating rule: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/email-rules/{rule_id}")
async def delete_rule(rule_id: int):
    """Delete email rule"""
    try:
        query = "DELETE FROM email_rules WHERE id = %s"
        execute_query(query, (rule_id,))
        
        return {
            "success": True,
            "message": f"Rule {rule_id} deleted"
        }
    
    except Exception as e:
        logger.error(f"❌ Error deleting rule: {e}")
        raise HTTPException(status_code=500, detail=str(e))


# Statistics Endpoint
@router.get("/emails/stats/summary")
async def get_email_stats():
    """Get email processing statistics"""
    try:
        query = """
            SELECT 
                COUNT(*) as total_emails,
                COUNT(CASE WHEN status = 'new' THEN 1 END) as new_emails,
                COUNT(CASE WHEN status = 'processed' THEN 1 END) as processed_emails,
                COUNT(CASE WHEN classification = 'invoice' THEN 1 END) as invoices,
                COUNT(CASE WHEN classification = 'time_confirmation' THEN 1 END) as time_confirmations,
                COUNT(CASE WHEN classification = 'spam' THEN 1 END) as spam_emails,
                COUNT(CASE WHEN auto_processed THEN 1 END) as auto_processed,
                AVG(confidence_score) as avg_confidence
            FROM email_messages
            WHERE deleted_at IS NULL
        """
        
        result = execute_query(query)
        return result[0] if result else {}
    
    except Exception as e:
        logger.error(f"❌ Error getting stats: {e}")
        raise HTTPException(status_code=500, detail=str(e))