"""
Company endpoints for API v1.

Provides CRUD operations for Company entities with filtering and search.
"""
from typing import List, Optional
from uuid import UUID
from django.shortcuts import get_object_or_404
from django.db.models import Q
from ninja import Router, Query
from ninja.pagination import paginate, PageNumberPagination

from apps.entities.models import Company
from apps.entities.services.company_submission import CompanySubmissionService
from apps.users.permissions import jwt_auth, require_auth
from ..schemas import (
    CompanyCreate,
    CompanyUpdate,
    CompanyOut,
    CompanyListOut,
    ErrorResponse,
    HistoryListResponse,
    HistoryEventDetailSchema,
    HistoryComparisonSchema,
    HistoryDiffCurrentSchema,
    FieldHistorySchema,
    HistoryActivitySummarySchema,
    RollbackRequestSchema,
    RollbackResponseSchema,
    ErrorSchema
)
from ..services.history_service import HistoryService
from django.core.exceptions import ValidationError
import logging

logger = logging.getLogger(__name__)


router = Router(tags=["Companies"])


class CompanyPagination(PageNumberPagination):
    """Custom pagination for companies."""
    page_size = 50


@router.get(
    "/",
    response={200: List[CompanyOut]},
    summary="List companies",
    description="Get a paginated list of companies with optional filtering"
)
@paginate(CompanyPagination)
def list_companies(
    request,
    search: Optional[str] = Query(None, description="Search by company name"),
    company_type: Optional[str] = Query(None, description="Filter by company type"),
    location_id: Optional[UUID] = Query(None, description="Filter by location"),
    ordering: Optional[str] = Query("-created", description="Sort by field (prefix with - for descending)")
):
    """
    List all companies with optional filters.
    
    **Filters:**
    - search: Search company names (case-insensitive partial match)
    - company_type: Filter by specific company type
    - location_id: Filter by headquarters location
    - ordering: Sort results (default: -created)
    
    **Returns:** Paginated list of companies
    """
    queryset = Company.objects.all()
    
    # Apply search filter
    if search:
        queryset = queryset.filter(
            Q(name__icontains=search) | Q(description__icontains=search)
        )
    
    # Apply company type filter
    if company_type:
        queryset = queryset.filter(company_types__contains=[company_type])
    
    # Apply location filter
    if location_id:
        queryset = queryset.filter(location_id=location_id)
    
    # Apply ordering
    valid_order_fields = ['name', 'created', 'modified', 'founded_date', 'park_count', 'ride_count']
    order_field = ordering.lstrip('-')
    if order_field in valid_order_fields:
        queryset = queryset.order_by(ordering)
    else:
        queryset = queryset.order_by('-created')
    
    return queryset


@router.get(
    "/{company_id}",
    response={200: CompanyOut, 404: ErrorResponse},
    summary="Get company",
    description="Retrieve a single company by ID"
)
def get_company(request, company_id: UUID):
    """
    Get a company by ID.
    
    **Parameters:**
    - company_id: UUID of the company
    
    **Returns:** Company details
    """
    company = get_object_or_404(Company, id=company_id)
    return company


@router.post(
    "/",
    response={201: CompanyOut, 202: dict, 400: ErrorResponse, 401: ErrorResponse},
    summary="Create company",
    description="Create a new company through the Sacred Pipeline (requires authentication)"
)
@require_auth
def create_company(request, payload: CompanyCreate):
    """
    Create a new company through the Sacred Pipeline.
    
    **Authentication:** Required
    
    **Parameters:**
    - payload: Company data (name, company_types, headquarters, etc.)
    
    **Returns:** Created company (moderators) or submission confirmation (regular users)
    
    **Flow:**
    - Moderators: Company created immediately (bypass moderation)
    - Regular users: Submission created, enters moderation queue
    
    **Note:** All companies flow through ContentSubmission pipeline for moderation.
    """
    try:
        user = request.auth
        
        # Create company through Sacred Pipeline
        submission, company = CompanySubmissionService.create_entity_submission(
            user=user,
            data=payload.dict(),
            source='api',
            ip_address=request.META.get('REMOTE_ADDR'),
            user_agent=request.META.get('HTTP_USER_AGENT', '')
        )
        
        # If moderator bypass happened, Company was created immediately
        if company:
            logger.info(f"Company created (moderator): {company.id} by {user.email}")
            return 201, company
        
        # Regular user: submission pending moderation
        logger.info(f"Company submission created: {submission.id} by {user.email}")
        return 202, {
            'submission_id': str(submission.id),
            'status': submission.status,
            'message': 'Company submission pending moderation. You will be notified when it is approved.',
        }
        
    except ValidationError as e:
        return 400, {'detail': str(e)}
    except Exception as e:
        logger.error(f"Error creating company: {e}")
        return 400, {'detail': str(e)}


@router.put(
    "/{company_id}",
    response={200: CompanyOut, 202: dict, 404: ErrorResponse, 400: ErrorResponse, 401: ErrorResponse},
    summary="Update company",
    description="Update an existing company through the Sacred Pipeline (requires authentication)"
)
@require_auth
def update_company(request, company_id: UUID, payload: CompanyUpdate):
    """
    Update a company through the Sacred Pipeline.
    
    **Authentication:** Required
    
    **Parameters:**
    - company_id: UUID of the company
    - payload: Updated company data
    
    **Returns:** Updated company (moderators) or submission confirmation (regular users)
    
    **Flow:**
    - Moderators: Updates applied immediately (bypass moderation)
    - Regular users: Submission created, enters moderation queue
    
    **Note:** All updates flow through ContentSubmission pipeline for moderation.
    """
    try:
        user = request.auth
        company = get_object_or_404(Company, id=company_id)
        
        data = payload.dict(exclude_unset=True)
        
        # Update company through Sacred Pipeline
        submission, updated_company = CompanySubmissionService.update_entity_submission(
            entity=company,
            user=user,
            update_data=data,
            source='api',
            ip_address=request.META.get('REMOTE_ADDR'),
            user_agent=request.META.get('HTTP_USER_AGENT', '')
        )
        
        # If moderator bypass happened, company was updated immediately
        if updated_company:
            logger.info(f"Company updated (moderator): {updated_company.id} by {user.email}")
            return 200, updated_company
        
        # Regular user: submission pending moderation
        logger.info(f"Company update submission created: {submission.id} by {user.email}")
        return 202, {
            'submission_id': str(submission.id),
            'status': submission.status,
            'message': 'Company update pending moderation. You will be notified when it is approved.',
        }
        
    except ValidationError as e:
        return 400, {'detail': str(e)}
    except Exception as e:
        logger.error(f"Error updating company: {e}")
        return 400, {'detail': str(e)}


@router.patch(
    "/{company_id}",
    response={200: CompanyOut, 202: dict, 404: ErrorResponse, 400: ErrorResponse, 401: ErrorResponse},
    summary="Partial update company",
    description="Partially update an existing company through the Sacred Pipeline (requires authentication)"
)
@require_auth
def partial_update_company(request, company_id: UUID, payload: CompanyUpdate):
    """
    Partially update a company through the Sacred Pipeline.
    
    **Authentication:** Required
    
    **Parameters:**
    - company_id: UUID of the company
    - payload: Fields to update (only provided fields are updated)
    
    **Returns:** Updated company (moderators) or submission confirmation (regular users)
    
    **Flow:**
    - Moderators: Updates applied immediately (bypass moderation)
    - Regular users: Submission created, enters moderation queue
    
    **Note:** All updates flow through ContentSubmission pipeline for moderation.
    """
    try:
        user = request.auth
        company = get_object_or_404(Company, id=company_id)
        
        data = payload.dict(exclude_unset=True)
        
        # Update company through Sacred Pipeline
        submission, updated_company = CompanySubmissionService.update_entity_submission(
            entity=company,
            user=user,
            update_data=data,
            source='api',
            ip_address=request.META.get('REMOTE_ADDR'),
            user_agent=request.META.get('HTTP_USER_AGENT', '')
        )
        
        # If moderator bypass happened, company was updated immediately
        if updated_company:
            logger.info(f"Company partially updated (moderator): {updated_company.id} by {user.email}")
            return 200, updated_company
        
        # Regular user: submission pending moderation
        logger.info(f"Company partial update submission created: {submission.id} by {user.email}")
        return 202, {
            'submission_id': str(submission.id),
            'status': submission.status,
            'message': 'Company update pending moderation. You will be notified when it is approved.',
        }
        
    except ValidationError as e:
        return 400, {'detail': str(e)}
    except Exception as e:
        logger.error(f"Error partially updating company: {e}")
        return 400, {'detail': str(e)}


@router.delete(
    "/{company_id}",
    response={200: dict, 202: dict, 404: ErrorResponse, 400: ErrorResponse, 401: ErrorResponse},
    summary="Delete company",
    description="Delete a company through the Sacred Pipeline (requires authentication)"
)
@require_auth
def delete_company(request, company_id: UUID):
    """
    Delete a company through the Sacred Pipeline.
    
    **Authentication:** Required
    
    **Parameters:**
    - company_id: UUID of the company
    
    **Returns:** Deletion confirmation (moderators) or submission confirmation (regular users)
    
    **Flow:**
    - Moderators: Company hard-deleted immediately (removed from database)
    - Regular users: Deletion request created, enters moderation queue
    
    **Deletion Strategy:**
    - Hard Delete: Removes company from database (Company has no status field for soft delete)
    
    **Note:** All deletions flow through ContentSubmission pipeline for moderation.
    **Warning:** Deleting a company may affect related parks and rides.
    """
    try:
        user = request.auth
        company = get_object_or_404(Company, id=company_id)
        
        # Delete company through Sacred Pipeline (hard delete - no status field)
        submission, deleted = CompanySubmissionService.delete_entity_submission(
            entity=company,
            user=user,
            deletion_type='hard',  # Company has no status field
            deletion_reason='',
            source='api',
            ip_address=request.META.get('REMOTE_ADDR'),
            user_agent=request.META.get('HTTP_USER_AGENT', '')
        )
        
        # If moderator bypass happened, deletion was applied immediately
        if deleted:
            logger.info(f"Company deleted (moderator): {company_id} by {user.email}")
            return 200, {
                'message': 'Company deleted successfully',
                'entity_id': str(company_id),
                'deletion_type': 'hard'
            }
        
        # Regular user: deletion pending moderation
        logger.info(f"Company deletion submission created: {submission.id} by {user.email}")
        return 202, {
            'submission_id': str(submission.id),
            'status': submission.status,
            'message': 'Company deletion request pending moderation. You will be notified when it is approved.',
            'entity_id': str(company_id)
        }
        
    except ValidationError as e:
        return 400, {'detail': str(e)}
    except Exception as e:
        logger.error(f"Error deleting company: {e}")
        return 400, {'detail': str(e)}


@router.get(
    "/{company_id}/parks",
    response={200: List[dict], 404: ErrorResponse},
    summary="Get company parks",
    description="Get all parks operated by a company"
)
def get_company_parks(request, company_id: UUID):
    """
    Get parks operated by a company.
    
    **Parameters:**
    - company_id: UUID of the company
    
    **Returns:** List of parks
    """
    company = get_object_or_404(Company, id=company_id)
    parks = company.operated_parks.all().values('id', 'name', 'slug', 'status', 'park_type')
    return list(parks)


@router.get(
    "/{company_id}/rides",
    response={200: List[dict], 404: ErrorResponse},
    summary="Get company rides",
    description="Get all rides manufactured by a company"
)
def get_company_rides(request, company_id: UUID):
    """
    Get rides manufactured by a company.
    
    **Parameters:**
    - company_id: UUID of the company
    
    **Returns:** List of rides
    """
    company = get_object_or_404(Company, id=company_id)
    rides = company.manufactured_rides.all().values('id', 'name', 'slug', 'status', 'ride_category')
    return list(rides)


# ============================================================================
# History Endpoints
# ============================================================================

@router.get(
    '/{company_id}/history/',
    response={200: HistoryListResponse, 404: ErrorSchema},
    summary="Get company history",
    description="Get historical changes for a company"
)
def get_company_history(
    request,
    company_id: UUID,
    page: int = Query(1, ge=1),
    page_size: int = Query(50, ge=1, le=100),
    date_from: Optional[str] = Query(None, description="Filter from date (YYYY-MM-DD)"),
    date_to: Optional[str] = Query(None, description="Filter to date (YYYY-MM-DD)")
):
    """Get history for a company."""
    from datetime import datetime
    
    # Verify company exists
    company = get_object_or_404(Company, id=company_id)
    
    # Parse dates if provided
    date_from_obj = datetime.fromisoformat(date_from).date() if date_from else None
    date_to_obj = datetime.fromisoformat(date_to).date() if date_to else None
    
    # Get history
    offset = (page - 1) * page_size
    events, accessible_count = HistoryService.get_history(
        'company', str(company_id), request.user,
        date_from=date_from_obj, date_to=date_to_obj,
        limit=page_size, offset=offset
    )
    
    # Format events
    formatted_events = []
    for event in events:
        formatted_events.append({
            'id': event['id'],
            'timestamp': event['timestamp'],
            'operation': event['operation'],
            'snapshot': event['snapshot'],
            'changed_fields': event.get('changed_fields'),
            'change_summary': event.get('change_summary', ''),
            'can_rollback': HistoryService.can_rollback(request.user)
        })
    
    # Calculate pagination
    total_pages = (accessible_count + page_size - 1) // page_size
    
    return {
        'entity_id': str(company_id),
        'entity_type': 'company',
        'entity_name': company.name,
        'total_events': accessible_count,
        'accessible_events': accessible_count,
        'access_limited': HistoryService.is_access_limited(request.user),
        'access_reason': HistoryService.get_access_reason(request.user),
        'events': formatted_events,
        'pagination': {
            'page': page,
            'page_size': page_size,
            'total_pages': total_pages,
            'total_items': accessible_count
        }
    }


@router.get(
    '/{company_id}/history/{event_id}/',
    response={200: HistoryEventDetailSchema, 404: ErrorSchema},
    summary="Get specific company history event",
    description="Get detailed information about a specific historical event"
)
def get_company_history_event(request, company_id: UUID, event_id: int):
    """Get a specific history event for a company."""
    company = get_object_or_404(Company, id=company_id)
    event = HistoryService.get_event('company', event_id, request.user)
    
    if not event:
        return 404, {"error": "Event not found or not accessible"}
    
    return {
        'id': event['id'],
        'timestamp': event['timestamp'],
        'operation': event['operation'],
        'entity_id': str(company_id),
        'entity_type': 'company',
        'entity_name': company.name,
        'snapshot': event['snapshot'],
        'changed_fields': event.get('changed_fields'),
        'metadata': event.get('metadata', {}),
        'can_rollback': HistoryService.can_rollback(request.user),
        'rollback_preview': None
    }


@router.get(
    '/{company_id}/history/compare/',
    response={200: HistoryComparisonSchema, 400: ErrorSchema, 404: ErrorSchema},
    summary="Compare two company history events",
    description="Compare two historical events for a company"
)
def compare_company_history(
    request,
    company_id: UUID,
    event1: int = Query(..., description="First event ID"),
    event2: int = Query(..., description="Second event ID")
):
    """Compare two historical events for a company."""
    company = get_object_or_404(Company, id=company_id)
    
    try:
        comparison = HistoryService.compare_events(
            'company', event1, event2, request.user
        )
        
        if not comparison:
            return 404, {"error": "One or both events not found"}
        
        return {
            'entity_id': str(company_id),
            'entity_type': 'company',
            'entity_name': company.name,
            'event1': comparison['event1'],
            'event2': comparison['event2'],
            'differences': comparison['differences'],
            'changed_field_count': comparison['changed_field_count'],
            'unchanged_field_count': comparison['unchanged_field_count'],
            'time_between': comparison['time_between']
        }
    except ValueError as e:
        return 400, {"error": str(e)}


@router.get(
    '/{company_id}/history/{event_id}/diff-current/',
    response={200: HistoryDiffCurrentSchema, 404: ErrorSchema},
    summary="Compare historical event with current state",
    description="Compare a historical event with the current company state"
)
def diff_company_history_with_current(request, company_id: UUID, event_id: int):
    """Compare historical event with current company state."""
    company = get_object_or_404(Company, id=company_id)
    
    try:
        diff = HistoryService.compare_with_current(
            'company', event_id, company, request.user
        )
        
        if not diff:
            return 404, {"error": "Event not found"}
        
        return {
            'entity_id': str(company_id),
            'entity_type': 'company',
            'entity_name': company.name,
            'event': diff['event'],
            'current_state': diff['current_state'],
            'differences': diff['differences'],
            'changed_field_count': diff['changed_field_count'],
            'time_since': diff['time_since']
        }
    except ValueError as e:
        return 404, {"error": str(e)}


@router.post(
    '/{company_id}/history/{event_id}/rollback/',
    response={200: RollbackResponseSchema, 400: ErrorSchema, 403: ErrorSchema},
    summary="Rollback company to historical state",
    description="Rollback company to a historical state (Moderators/Admins only)"
)
def rollback_company(request, company_id: UUID, event_id: int, payload: RollbackRequestSchema):
    """
    Rollback company to a historical state.
    
    **Permission:** Moderators, Admins, Superusers only
    """
    # Check authentication
    if not request.user or not request.user.is_authenticated:
        return 401, {"error": "Authentication required"}
    
    # Check rollback permission
    if not HistoryService.can_rollback(request.user):
        return 403, {"error": "Only moderators and administrators can perform rollbacks"}
    
    company = get_object_or_404(Company, id=company_id)
    
    try:
        result = HistoryService.rollback_to_event(
            company, 'company', event_id, request.user,
            fields=payload.fields,
            comment=payload.comment,
            create_backup=payload.create_backup
        )
        return result
    except (ValueError, PermissionError) as e:
        return 400, {"error": str(e)}


@router.get(
    '/{company_id}/history/field/{field_name}/',
    response={200: FieldHistorySchema, 404: ErrorSchema},
    summary="Get field-specific history",
    description="Get history of changes to a specific company field"
)
def get_company_field_history(request, company_id: UUID, field_name: str):
    """Get history of changes to a specific company field."""
    company = get_object_or_404(Company, id=company_id)
    
    history = HistoryService.get_field_history(
        'company', str(company_id), field_name, request.user
    )
    
    return {
        'entity_id': str(company_id),
        'entity_type': 'company',
        'entity_name': company.name,
        'field': field_name,
        'field_type': 'CharField',  # Could introspect this
        **history
    }


@router.get(
    '/{company_id}/history/summary/',
    response={200: HistoryActivitySummarySchema, 404: ErrorSchema},
    summary="Get company activity summary",
    description="Get activity summary for a company"
)
def get_company_activity_summary(request, company_id: UUID):
    """Get activity summary for a company."""
    company = get_object_or_404(Company, id=company_id)
    
    summary = HistoryService.get_activity_summary(
        'company', str(company_id), request.user
    )
    
    return {
        'entity_id': str(company_id),
        'entity_type': 'company',
        'entity_name': company.name,
        **summary
    }