"""Data export/import endpoints."""

import csv
import io
import json
from datetime import datetime
from typing import Any, List
from fastapi import APIRouter, Depends, HTTPException, status, UploadFile, File, Response
from fastapi.responses import StreamingResponse
from sqlalchemy.orm import Session
from pydantic import BaseModel

from app.dependencies import get_db, get_current_superuser
from app.models.user import User
from app.models.audit_log import AuditLog
from app import crud, schemas


router = APIRouter()


class ImportResult(BaseModel):
    """Import operation result."""
    success: int = 0
    failed: int = 0
    errors: List[str] = []


# =============================================================================
# EXPORT ENDPOINTS
# =============================================================================

@router.get("/users/csv")
def export_users_csv(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
):
    """
    Export all users to CSV format.
    """
    users = db.query(User).all()

    # Create CSV in memory
    output = io.StringIO()
    writer = csv.writer(output)

    # Header
    writer.writerow([
        "id", "username", "email", "is_active", "is_superuser",
        "totp_enabled", "created_at", "last_login"
    ])

    # Data rows
    for user in users:
        writer.writerow([
            user.id,
            user.username,
            user.email,
            user.is_active,
            user.is_superuser,
            user.totp_enabled,
            user.created_at.isoformat() if user.created_at else "",
            user.last_login.isoformat() if user.last_login else ""
        ])

    output.seek(0)

    # Log export
    crud.audit_log.log_action(
        db,
        user_id=current_user.id,
        username=current_user.username,
        action="export",
        resource_type="users",
        details={"format": "csv", "count": len(users)},
        status="success"
    )

    return StreamingResponse(
        iter([output.getvalue()]),
        media_type="text/csv",
        headers={
            "Content-Disposition": f"attachment; filename=users_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.csv"
        }
    )


@router.get("/users/json")
def export_users_json(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
):
    """
    Export all users to JSON format.
    """
    users = db.query(User).all()

    data = {
        "exported_at": datetime.utcnow().isoformat(),
        "exported_by": current_user.username,
        "count": len(users),
        "users": [
            {
                "id": user.id,
                "username": user.username,
                "email": user.email,
                "is_active": user.is_active,
                "is_superuser": user.is_superuser,
                "totp_enabled": user.totp_enabled,
                "permissions": user.permissions,
                "created_at": user.created_at.isoformat() if user.created_at else None,
                "last_login": user.last_login.isoformat() if user.last_login else None
            }
            for user in users
        ]
    }

    # Log export
    crud.audit_log.log_action(
        db,
        user_id=current_user.id,
        username=current_user.username,
        action="export",
        resource_type="users",
        details={"format": "json", "count": len(users)},
        status="success"
    )

    content = json.dumps(data, indent=2)

    return Response(
        content=content,
        media_type="application/json",
        headers={
            "Content-Disposition": f"attachment; filename=users_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.json"
        }
    )


@router.get("/settings/json")
def export_settings_json(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
):
    """
    Export all settings to JSON format.
    """
    from app.models.settings import Settings

    settings_list = db.query(Settings).all()

    data = {
        "exported_at": datetime.utcnow().isoformat(),
        "exported_by": current_user.username,
        "count": len(settings_list),
        "settings": {
            setting.key: setting.value
            for setting in settings_list
        }
    }

    # Log export
    crud.audit_log.log_action(
        db,
        user_id=current_user.id,
        username=current_user.username,
        action="export",
        resource_type="settings",
        details={"format": "json", "count": len(settings_list)},
        status="success"
    )

    content = json.dumps(data, indent=2)

    return Response(
        content=content,
        media_type="application/json",
        headers={
            "Content-Disposition": f"attachment; filename=settings_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.json"
        }
    )


@router.get("/audit/csv")
def export_audit_csv(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
    days: int = 30
):
    """
    Export audit logs to CSV format.
    """
    from datetime import timedelta

    since = datetime.utcnow() - timedelta(days=days)
    logs = db.query(AuditLog).filter(AuditLog.created_at >= since).all()

    # Create CSV in memory
    output = io.StringIO()
    writer = csv.writer(output)

    # Header
    writer.writerow([
        "id", "user_id", "username", "action", "resource_type",
        "resource_id", "status", "ip_address", "created_at"
    ])

    # Data rows
    for log in logs:
        writer.writerow([
            log.id,
            log.user_id,
            log.username,
            log.action,
            log.resource_type,
            log.resource_id,
            log.status,
            log.ip_address,
            log.created_at.isoformat() if log.created_at else ""
        ])

    output.seek(0)

    return StreamingResponse(
        iter([output.getvalue()]),
        media_type="text/csv",
        headers={
            "Content-Disposition": f"attachment; filename=audit_logs_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.csv"
        }
    )


# =============================================================================
# IMPORT ENDPOINTS
# =============================================================================

@router.post("/users/json", response_model=ImportResult)
async def import_users_json(
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
):
    """
    Import users from JSON file.
    Only creates new users, does not update existing ones.
    """
    result = ImportResult()

    try:
        content = await file.read()
        data = json.loads(content.decode())
    except json.JSONDecodeError as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Invalid JSON file: {str(e)}"
        )

    users_data = data.get("users", [])
    if not users_data:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="No users found in file"
        )

    for user_data in users_data:
        try:
            username = user_data.get("username")
            email = user_data.get("email")

            # Check if user already exists
            if crud.user.get_by_username(db, username=username):
                result.errors.append(f"User '{username}' already exists")
                result.failed += 1
                continue

            if crud.user.get_by_email(db, email=email):
                result.errors.append(f"Email '{email}' already exists")
                result.failed += 1
                continue

            # Create user with a default password (must be changed)
            import secrets
            temp_password = secrets.token_urlsafe(16)

            user_create = schemas.UserCreate(
                username=username,
                email=email,
                password=temp_password,
                is_active=user_data.get("is_active", True),
                is_superuser=user_data.get("is_superuser", False),
                permissions=user_data.get("permissions")
            )

            crud.user.create(db, obj_in=user_create)
            result.success += 1

        except Exception as e:
            result.errors.append(f"Error importing user: {str(e)}")
            result.failed += 1

    # Log import
    crud.audit_log.log_action(
        db,
        user_id=current_user.id,
        username=current_user.username,
        action="import",
        resource_type="users",
        details={
            "format": "json",
            "success": result.success,
            "failed": result.failed
        },
        status="success" if result.failed == 0 else "partial"
    )

    return result


@router.post("/settings/json", response_model=ImportResult)
async def import_settings_json(
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_superuser),
):
    """
    Import settings from JSON file.
    Updates existing settings and creates new ones.
    """
    result = ImportResult()

    try:
        content = await file.read()
        data = json.loads(content.decode())
    except json.JSONDecodeError as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Invalid JSON file: {str(e)}"
        )

    settings_data = data.get("settings", {})
    if not settings_data:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="No settings found in file"
        )

    for key, value in settings_data.items():
        try:
            crud.settings.update_setting(db, key=key, value=value)
            result.success += 1
        except Exception as e:
            result.errors.append(f"Error importing setting '{key}': {str(e)}")
            result.failed += 1

    # Log import
    crud.audit_log.log_action(
        db,
        user_id=current_user.id,
        username=current_user.username,
        action="import",
        resource_type="settings",
        details={
            "format": "json",
            "success": result.success,
            "failed": result.failed
        },
        status="success" if result.failed == 0 else "partial"
    )

    return result