/**
 * ID Mapping Domain - Validation
 * 
 * Pure business validation functions for ID mappings.
 * These functions contain no infrastructure dependencies (no DB, no HTTP, no logging).
 */

import { z } from "zod";
import {
  createMappingRequestSchema,
  updateMappingRequestSchema,
  userIdMappingSchema,
} from "./schema";
import type {
  CreateMappingRequest,
  UpdateMappingRequest,
  UserIdMapping,
  MappingValidationResult,
} from "./contract";

/**
 * Validate a create mapping request format
 */
export function validateCreateRequest(request: CreateMappingRequest): MappingValidationResult {
  const validationResult = createMappingRequestSchema.safeParse(request);

  if (validationResult.success) {
    const warnings: string[] = [];
    if (!request.sfAccountId) {
      warnings.push("Salesforce account ID not provided - mapping will be incomplete");
    }
    return { isValid: true, errors: [], warnings };
  }

  const errors = validationResult.error.issues.map(issue => issue.message);
  return { isValid: false, errors, warnings: [] };
}

/**
 * Validate an update mapping request format
 */
export function validateUpdateRequest(
  userId: string,
  request: UpdateMappingRequest
): MappingValidationResult {
  // First validate userId
  const userIdValidation = z.string().uuid().safeParse(userId);
  if (!userIdValidation.success) {
    return {
      isValid: false,
      errors: ["User ID must be a valid UUID"],
      warnings: [],
    };
  }

  // Then validate the update request
  const validationResult = updateMappingRequestSchema.safeParse(request);

  if (validationResult.success) {
    return { isValid: true, errors: [], warnings: [] };
  }

  const errors = validationResult.error.issues.map(issue => issue.message);
  return { isValid: false, errors, warnings: [] };
}

/**
 * Validate an existing mapping
 */
export function validateExistingMapping(mapping: UserIdMapping): MappingValidationResult {
  const validationResult = userIdMappingSchema.safeParse(mapping);

  if (validationResult.success) {
    const warnings: string[] = [];
    if (!mapping.sfAccountId) {
      warnings.push("Mapping is missing Salesforce account ID");
    }
    return { isValid: true, errors: [], warnings };
  }

  const errors = validationResult.error.issues.map(issue => issue.message);
  return { isValid: false, errors, warnings: [] };
}

/**
 * Validate bulk mappings
 */
export function validateBulkMappings(
  mappings: CreateMappingRequest[]
): Array<{ index: number; validation: MappingValidationResult }> {
  return mappings.map((mapping, index) => ({
    index,
    validation: validateCreateRequest(mapping),
  }));
}

/**
 * Validate no conflicts exist with existing mappings
 * Business rule: Each userId, whmcsClientId should be unique
 */
export function validateNoConflicts(
  request: CreateMappingRequest,
  existingMappings: UserIdMapping[]
): MappingValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  // First validate the request format
  const formatValidation = validateCreateRequest(request);
  if (!formatValidation.isValid) {
    return formatValidation;
  }

  // Check for conflicts
  const duplicateUser = existingMappings.find(m => m.userId === request.userId);
  if (duplicateUser) {
    errors.push(`User ${request.userId} already has a mapping`);
  }

  const duplicateWhmcs = existingMappings.find(m => m.whmcsClientId === request.whmcsClientId);
  if (duplicateWhmcs) {
    errors.push(
      `WHMCS client ${request.whmcsClientId} is already mapped to user ${duplicateWhmcs.userId}`
    );
  }

  if (request.sfAccountId) {
    const duplicateSf = existingMappings.find(m => m.sfAccountId === request.sfAccountId);
    if (duplicateSf) {
      warnings.push(
        `Salesforce account ${request.sfAccountId} is already mapped to user ${duplicateSf.userId}`
      );
    }
  }

  return { isValid: errors.length === 0, errors, warnings };
}

/**
 * Validate deletion constraints
 * Business rule: Warn about data access impacts
 */
export function validateDeletion(mapping: UserIdMapping | null | undefined): MappingValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!mapping) {
    errors.push("Cannot delete non-existent mapping");
    return { isValid: false, errors, warnings };
  }

  // Validate the mapping format
  const formatValidation = validateExistingMapping(mapping);
  if (!formatValidation.isValid) {
    return formatValidation;
  }

  warnings.push(
    "Deleting this mapping will prevent access to WHMCS/Salesforce data for this user"
  );
  if (mapping.sfAccountId) {
    warnings.push(
      "This mapping includes Salesforce integration - deletion will affect case management"
    );
  }

  return { isValid: true, errors, warnings };
}

/**
 * Sanitize and normalize a create mapping request
 * 
 * Note: This performs basic string trimming before validation.
 * The schema handles validation; this is purely for data cleanup.
 */
export function sanitizeCreateRequest(request: CreateMappingRequest): CreateMappingRequest {
  return {
    userId: request.userId?.trim(),
    whmcsClientId: request.whmcsClientId,
    sfAccountId: request.sfAccountId?.trim() || undefined,
  };
}

/**
 * Sanitize and normalize an update mapping request
 * 
 * Note: This performs basic string trimming before validation.
 * The schema handles validation; this is purely for data cleanup.
 */
export function sanitizeUpdateRequest(request: UpdateMappingRequest): UpdateMappingRequest {
  const sanitized: Partial<UpdateMappingRequest> = {};

  if (request.whmcsClientId !== undefined) {
    sanitized.whmcsClientId = request.whmcsClientId;
  }

  if (request.sfAccountId !== undefined) {
    sanitized.sfAccountId = request.sfAccountId?.trim() || undefined;
  }

  return sanitized;
}