import { z } from 'zod';
import { supabase } from '@/integrations/supabase/client';

// ============================================
// CENTRALIZED VALIDATION SCHEMAS
// Single source of truth for all entity validation
// ============================================

const currentYear = new Date().getFullYear();

// ============================================
// SHARED IMAGE UPLOAD SCHEMA
// ============================================

const imageAssignmentSchema = z.object({
  uploaded: z.array(z.any()),
  banner_assignment: z.number().int().min(0).nullable().optional(),
  card_assignment: z.number().int().min(0).nullable().optional()
}).optional().default({ uploaded: [], banner_assignment: null, card_assignment: null });

// ============================================
// PARK SCHEMA
// ============================================

export const parkValidationSchema = z.object({
  name: z.string().trim().min(1, 'Park name is required').max(200, 'Name must be less than 200 characters'),
  slug: z.string().trim().min(1, 'Slug is required').regex(/^[a-z0-9-]+$/, 'Slug must contain only lowercase letters, numbers, and hyphens'),
  description: z.string().trim().max(2000, 'Description must be less than 2000 characters').optional().or(z.literal('')),
  park_type: z.string().min(1, 'Park type is required'),
  status: z.string().min(1, 'Status is required'),
  opening_date: z.string().optional().or(z.literal('')).refine((val) => {
    if (!val) return true;
    const date = new Date(val);
    return date <= new Date();
  }, 'Opening date cannot be in the future'),
  opening_date_precision: z.enum(['day', 'month', 'year']).optional(),
  closing_date: z.string().optional().or(z.literal('')),
  closing_date_precision: z.enum(['day', 'month', 'year']).optional(),
  location_id: z.string().uuid().optional().nullable(),
  website_url: z.string().trim().optional().or(z.literal('')).refine((val) => {
    if (!val || val === '') return true;
    return z.string().url().safeParse(val).success;
  }, 'Invalid URL format'),
  phone: z.string().trim().max(50, 'Phone must be less than 50 characters').optional().or(z.literal('')),
  email: z.string().trim().optional().or(z.literal('')).refine((val) => {
    if (!val || val === '') return true;
    return z.string().email().safeParse(val).success;
  }, 'Invalid email format'),
  operator_id: z.string().uuid().optional().nullable(),
  property_owner_id: z.string().uuid().optional().nullable(),
  banner_image_id: z.string().optional(),
  banner_image_url: z.string().optional(),
  card_image_id: z.string().optional(),
  card_image_url: z.string().optional(),
  images: imageAssignmentSchema,
}).refine((data) => {
  if (data.closing_date && data.opening_date) {
    return new Date(data.closing_date) >= new Date(data.opening_date);
  }
  return true;
}, {
  message: 'Closing date must be after opening date',
  path: ['closing_date'],
});

// ============================================
// RIDE SCHEMA
// ============================================

export const rideValidationSchema = z.object({
  name: z.string().trim().min(1, 'Ride name is required').max(200, 'Name must be less than 200 characters'),
  slug: z.string().trim().min(1, 'Slug is required').regex(/^[a-z0-9-]+$/, 'Slug must contain only lowercase letters, numbers, and hyphens'),
  description: z.string().trim().max(2000, 'Description must be less than 2000 characters').optional().or(z.literal('')),
  category: z.string().min(1, 'Category is required'),
  ride_sub_type: z.string().trim().max(100, 'Sub type must be less than 100 characters').optional().or(z.literal('')),
  status: z.string().min(1, 'Status is required'),
  park_id: z.string().uuid().optional().nullable(),
  designer_id: z.string().uuid().optional().nullable(),
  opening_date: z.string().optional().or(z.literal('')),
  opening_date_precision: z.enum(['day', 'month', 'year']).optional(),
  closing_date: z.string().optional().or(z.literal('')),
  closing_date_precision: z.enum(['day', 'month', 'year']).optional(),
  height_requirement: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(0, 'Height requirement must be positive').max(300, 'Height requirement must be less than 300cm').optional()
  ),
  age_requirement: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(0, 'Age requirement must be positive').max(100, 'Age requirement must be less than 100').optional()
  ),
  capacity_per_hour: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(1, 'Capacity must be positive').max(99999, 'Capacity must be less than 100,000').optional()
  ),
  duration_seconds: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(1, 'Duration must be positive').max(86400, 'Duration must be less than 24 hours').optional()
  ),
  max_speed_kmh: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().min(0, 'Speed must be positive').max(500, 'Speed must be less than 500 km/h').optional()
  ),
  max_height_meters: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().min(0, 'Height must be positive').max(200, 'Height must be less than 200 meters').optional()
  ),
  length_meters: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().min(0, 'Length must be positive').max(10000, 'Length must be less than 10km').optional()
  ),
  inversions: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(0, 'Inversions must be positive').max(20, 'Inversions must be less than 20').optional()
  ),
  drop_height_meters: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().min(0, 'Drop height must be positive').max(200, 'Drop height must be less than 200 meters').optional()
  ),
  max_g_force: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().min(-10, 'G-force must be greater than -10').max(10, 'G-force must be less than 10').optional()
  ),
  manufacturer_id: z.string().uuid().optional().nullable(),
  ride_model_id: z.string().uuid().optional().nullable(),
  coaster_type: z.string().optional(),
  seating_type: z.string().optional(),
  intensity_level: z.string().optional(),
  track_material: z.enum(['wood', 'steel', 'hybrid', 'aluminum', 'other']).optional(),
  banner_image_id: z.string().optional(),
  banner_image_url: z.string().optional(),
  card_image_id: z.string().optional(),
  card_image_url: z.string().optional(),
  images: imageAssignmentSchema,
});

// ============================================
// COMPANY SCHEMA (Manufacturer, Designer, Operator, Property Owner)
// ============================================

export const companyValidationSchema = z.object({
  name: z.string().trim().min(1, 'Company name is required').max(200, 'Name must be less than 200 characters'),
  slug: z.string().trim().min(1, 'Slug is required').regex(/^[a-z0-9-]+$/, 'Slug must contain only lowercase letters, numbers, and hyphens'),
  company_type: z.enum(['manufacturer', 'designer', 'operator', 'property_owner']),
  description: z.string().trim().max(2000, 'Description must be less than 2000 characters').optional().or(z.literal('')),
  person_type: z.enum(['company', 'individual', 'firm', 'organization']),
  founded_date: z.string().optional().or(z.literal('')),
  founded_date_precision: z.enum(['day', 'month', 'year']).optional(),
  founded_year: z.preprocess(
    (val) => val === '' || val === null || val === undefined ? undefined : Number(val),
    z.number().int().min(1800, 'Founded year must be after 1800').max(currentYear, `Founded year cannot be after ${currentYear}`).optional()
  ),
  headquarters_location: z.string().trim().max(200, 'Location must be less than 200 characters').optional().or(z.literal('')),
  website_url: z.string().trim().optional().or(z.literal('')).refine((val) => {
    if (!val || val === '') return true;
    return z.string().url().safeParse(val).success;
  }, 'Invalid URL format'),
  banner_image_id: z.string().optional(),
  banner_image_url: z.string().optional(),
  card_image_id: z.string().optional(),
  card_image_url: z.string().optional(),
  images: imageAssignmentSchema,
});

// ============================================
// RIDE MODEL SCHEMA
// ============================================

export const rideModelValidationSchema = z.object({
  name: z.string().trim().min(1, 'Model name is required').max(200, 'Name must be less than 200 characters'),
  slug: z.string().trim().min(1, 'Slug is required').regex(/^[a-z0-9-]+$/, 'Slug must contain only lowercase letters, numbers, and hyphens'),
  category: z.string().min(1, 'Category is required'),
  ride_type: z.string().trim().min(1, 'Ride type is required').max(100, 'Ride type must be less than 100 characters'),
  description: z.string().trim().max(2000, 'Description must be less than 2000 characters').optional().or(z.literal('')),
  manufacturer_id: z.string().uuid('Invalid manufacturer ID').optional(),
});

// ============================================
// PHOTO SCHEMA
// ============================================

export const photoValidationSchema = z.object({
  cloudflare_image_id: z.string().min(1, 'Image ID is required'),
  cloudflare_image_url: z.string().url('Invalid image URL'),
  entity_type: z.string().min(1, 'Entity type is required'),
  entity_id: z.string().uuid('Invalid entity ID'),
  caption: z.string().trim().max(500, 'Caption must be less than 500 characters').optional().or(z.literal('')),
  photographer_credit: z.string().trim().max(200, 'Credit must be less than 200 characters').optional().or(z.literal('')),
});

// ============================================
// MILESTONE/TIMELINE EVENT SCHEMA
// ============================================

export const milestoneValidationSchema = z.object({
  title: z.string().trim().min(1, 'Event title is required').max(200, 'Title must be less than 200 characters'),
  description: z.string().trim().max(2000, 'Description must be less than 2000 characters').optional().or(z.literal('')),
  event_type: z.string().min(1, 'Event type is required'),
  event_date: z.string().min(1, 'Event date is required'),
  event_date_precision: z.enum(['day', 'month', 'year']).optional(),
  entity_type: z.string().min(1, 'Entity type is required'),
  entity_id: z.string().uuid('Invalid entity ID'),
  is_public: z.boolean().optional(),
  display_order: z.number().optional(),
  from_value: z.string().optional(),
  to_value: z.string().optional(),
  from_entity_id: z.string().uuid().optional().nullable(),
  to_entity_id: z.string().uuid().optional().nullable(),
  from_location_id: z.string().uuid().optional().nullable(),
  to_location_id: z.string().uuid().optional().nullable(),
});

// ============================================
// SCHEMA REGISTRY
// ============================================

export const entitySchemas = {
  park: parkValidationSchema,
  ride: rideValidationSchema,
  manufacturer: companyValidationSchema,
  designer: companyValidationSchema,
  operator: companyValidationSchema,
  property_owner: companyValidationSchema,
  ride_model: rideModelValidationSchema,
  photo: photoValidationSchema,
  milestone: milestoneValidationSchema,
};

// ============================================
// VALIDATION RESULT TYPES
// ============================================

export interface ValidationError {
  field: string;
  message: string;
  severity: 'blocking' | 'warning' | 'suggestion';
}

export interface ValidationResult {
  isValid: boolean;
  blockingErrors: ValidationError[];
  warnings: ValidationError[];
  suggestions: ValidationError[];
  allErrors: ValidationError[];
}

// ============================================
// VALIDATION HELPERS
// ============================================

/**
 * Validate entity data against its schema
 * Returns detailed validation result with errors categorized by severity
 */
export async function validateEntityData(
  entityType: keyof typeof entitySchemas,
  data: unknown
): Promise<ValidationResult> {
  const schema = entitySchemas[entityType];
  
  if (!schema) {
    return {
      isValid: false,
      blockingErrors: [{ field: 'entity_type', message: `Unknown entity type: ${entityType}`, severity: 'blocking' }],
      warnings: [],
      suggestions: [],
      allErrors: [{ field: 'entity_type', message: `Unknown entity type: ${entityType}`, severity: 'blocking' }],
    };
  }

  const result = schema.safeParse(data);
  const blockingErrors: ValidationError[] = [];
  const warnings: ValidationError[] = [];
  const suggestions: ValidationError[] = [];

  // Process Zod errors
  if (!result.success) {
    const zodError = result.error as z.ZodError;
    zodError.issues.forEach((issue) => {
      const field = issue.path.join('.');
      blockingErrors.push({
        field: field || 'unknown',
        message: issue.message,
        severity: 'blocking',
      });
    });
  }

  // Add warnings for optional but recommended fields
  const validData = data as Record<string, unknown>;
  if (validData.description && typeof validData.description === 'string' && validData.description.length < 50) {
    warnings.push({
      field: 'description',
      message: 'Description is short. Recommended: 50+ characters',
      severity: 'warning',
    });
  }

  if (entityType === 'park' || entityType === 'ride') {
    if (!validData.description || (typeof validData.description === 'string' && validData.description.trim() === '')) {
      warnings.push({
        field: 'description',
        message: 'No description provided. Adding a description improves content quality',
        severity: 'warning',
      });
    }
  }

  // Check slug uniqueness (async)
  if (validData.slug && typeof validData.slug === 'string') {
    const isSlugUnique = await checkSlugUniqueness(
      entityType, 
      validData.slug, 
      typeof validData.id === 'string' ? validData.id : undefined
    );
    if (!isSlugUnique) {
      blockingErrors.push({
        field: 'slug',
        message: 'This slug is already in use. Please choose a unique slug',
        severity: 'blocking',
      });
    }
  }

  const allErrors = [...blockingErrors, ...warnings, ...suggestions];
  const isValid = blockingErrors.length === 0;

  return {
    isValid,
    blockingErrors,
    warnings,
    suggestions,
    allErrors,
  };
}

/**
 * Check if slug is unique for the entity type
 */
async function checkSlugUniqueness(
  entityType: keyof typeof entitySchemas,
  slug: string,
  excludeId?: string
): Promise<boolean> {
  const tableName = getTableNameFromEntityType(entityType);
  
  try {
    console.log(`Checking slug uniqueness for "${slug}" in ${tableName}, excludeId: ${excludeId}`);
    
    // Query with explicit table name - use simple approach to avoid type instantiation issues
    let result;
    
    switch (tableName) {
      case 'parks':
        result = await supabase.from('parks').select('id').eq('slug', slug).limit(1);
        break;
      case 'rides':
        result = await supabase.from('rides').select('id').eq('slug', slug).limit(1);
        break;
      case 'companies':
        result = await supabase.from('companies').select('id').eq('slug', slug).limit(1);
        break;
      case 'ride_models':
        result = await supabase.from('ride_models').select('id').eq('slug', slug).limit(1);
        break;
      default:
        console.error(`Invalid table name: ${tableName}`);
        return true; // Assume unique on invalid table
    }

    const { data, error } = result;

    if (error) {
      console.error(`Slug uniqueness check failed for ${entityType}:`, error);
      return true; // Assume unique on error to avoid blocking
    }

    // If no data, slug is unique
    if (!data || data.length === 0) {
      console.log(`Slug "${slug}" is unique in ${tableName}`);
      return true;
    }

    // If excludeId provided and matches, it's the same entity (editing)
    if (excludeId && data[0] && data[0].id === excludeId) {
      console.log(`Slug "${slug}" matches current entity (editing mode)`);
      return true;
    }

    // Slug is in use by a different entity
    console.log(`Slug "${slug}" already exists in ${tableName}`);
    return false;
  } catch (error) {
    console.error(`Exception during slug uniqueness check:`, error);
    return true; // Assume unique on error to avoid false positives
  }
}

/**
 * Get database table name from entity type
 */
function getTableNameFromEntityType(entityType: keyof typeof entitySchemas): string {
  switch (entityType) {
    case 'park':
      return 'parks';
    case 'ride':
      return 'rides';
    case 'manufacturer':
    case 'designer':
    case 'operator':
    case 'property_owner':
      return 'companies';
    case 'ride_model':
      return 'ride_models';
    case 'photo':
      return 'photos';
    default:
      return entityType + 's';
  }
}

/**
 * Batch validate multiple items
 */
export async function validateMultipleItems(
  items: Array<{ item_type: string; item_data: unknown; id?: string }>
): Promise<Map<string, ValidationResult>> {
  const results = new Map<string, ValidationResult>();

  await Promise.all(
    items.map(async (item) => {
      const result = await validateEntityData(
        item.item_type as keyof typeof entitySchemas,
        { ...(item.item_data as object), id: item.id }
      );
      const validData = item.item_data as Record<string, unknown>;
      results.set(
        item.id || (typeof validData.slug === 'string' ? validData.slug : ''), 
        result
      );
    })
  );

  return results;
}