import { BadRequestException, Inject, Injectable } from '@nestjs/common';
import {
  CUSTOMER_GATEWAY_POLICIES_REPOSITORY,
  type CreatePolicyInput,
  type CustomerGatewayPoliciesRepository,
  type CustomerGatewayPolicySummary,
  type PolicyMatchMode,
  type PolicyStatus,
  type UpdatePolicyInput
} from './customer-gateway-policies.repository.js';

interface CreatePolicyDto {
  lineGroupId?: unknown;
  name?: unknown;
  priority?: unknown;
  callerMode?: unknown;
  callerValue?: unknown;
  calleeMode?: unknown;
  calleeValue?: unknown;
  status?: unknown;
}

interface UpdatePolicyDto {
  lineGroupId?: unknown;
  name?: unknown;
  priority?: unknown;
  callerMode?: unknown;
  callerValue?: unknown;
  calleeMode?: unknown;
  calleeValue?: unknown;
  status?: unknown;
}

interface ReorderDto {
  policyIds?: unknown;
}

@Injectable()
export class CustomerGatewayPoliciesService {
  constructor(@Inject(CUSTOMER_GATEWAY_POLICIES_REPOSITORY) private readonly policies: CustomerGatewayPoliciesRepository) {}

  list(gatewayId: string): Promise<CustomerGatewayPolicySummary[]> {
    return this.policies.list(gatewayId);
  }

  create(gatewayId: string, body: CreatePolicyDto, actorId?: string): Promise<CustomerGatewayPolicySummary> {
    const callerMode = body.callerMode === undefined ? 'ANY' : this.matchMode(body.callerMode, 'callerMode');
    const calleeMode = body.calleeMode === undefined ? 'ANY' : this.matchMode(body.calleeMode, 'calleeMode');
    const input: CreatePolicyInput = {
      gatewayId,
      lineGroupId: this.limitedString(body.lineGroupId, 'lineGroupId', 32),
      name: this.limitedString(body.name, 'name', 120),
      priority: body.priority === undefined ? undefined : this.priority(body.priority),
      callerMode,
      callerValue: this.matchValue(callerMode, body.callerValue, 'callerValue'),
      calleeMode,
      calleeValue: this.matchValue(calleeMode, body.calleeValue, 'calleeValue'),
      status: body.status === undefined ? 'ENABLED' : this.status(body.status),
      actorId
    };
    return this.policies.create(input);
  }

  update(policyId: string, body: UpdatePolicyDto, actorId?: string): Promise<CustomerGatewayPolicySummary> {
    const callerMode = body.callerMode === undefined ? undefined : this.matchMode(body.callerMode, 'callerMode');
    const calleeMode = body.calleeMode === undefined ? undefined : this.matchMode(body.calleeMode, 'calleeMode');
    const input: UpdatePolicyInput = {
      lineGroupId: body.lineGroupId === undefined ? undefined : this.limitedString(body.lineGroupId, 'lineGroupId', 32),
      name: body.name === undefined ? undefined : this.limitedString(body.name, 'name', 120),
      priority: body.priority === undefined ? undefined : this.priority(body.priority),
      callerMode,
      callerValue: callerMode === undefined ? (body.callerValue === undefined ? undefined : this.nullableString(body.callerValue, 'callerValue', 64)) : this.matchValue(callerMode, body.callerValue, 'callerValue'),
      calleeMode,
      calleeValue: calleeMode === undefined ? (body.calleeValue === undefined ? undefined : this.nullableString(body.calleeValue, 'calleeValue', 64)) : this.matchValue(calleeMode, body.calleeValue, 'calleeValue'),
      status: body.status === undefined ? undefined : this.status(body.status),
      actorId
    };
    return this.policies.update(policyId, input);
  }

  remove(policyId: string, actorId?: string): Promise<CustomerGatewayPolicySummary> {
    return this.policies.softDelete(policyId, actorId);
  }

  reorder(gatewayId: string, body: ReorderDto, actorId?: string): Promise<CustomerGatewayPolicySummary[]> {
    if (!Array.isArray(body.policyIds) || body.policyIds.length === 0) {
      throw new BadRequestException({ code: 'POLICY_IDS_INVALID', message: 'policyIds must be a non-empty array.' });
    }
    return this.policies.reorder(
      gatewayId,
      body.policyIds.map((id) => this.limitedString(id, 'policyIds', 32)),
      actorId
    );
  }

  private limitedString(value: unknown, field: string, maxLength: number): string {
    if (typeof value !== 'string' || value.trim().length === 0) {
      throw new BadRequestException({ code: 'VALIDATION_ERROR', message: `${field} is required.` });
    }
    const trimmed = value.trim();
    if (trimmed.length > maxLength) {
      throw new BadRequestException({ code: 'VALIDATION_ERROR', message: `${field} is too long.` });
    }
    return trimmed;
  }

  private nullableString(value: unknown, field: string, maxLength: number): string | null {
    if (value === null) {
      return null;
    }
    return this.limitedString(value, field, maxLength);
  }

  private matchMode(value: unknown, field: string): PolicyMatchMode {
    if (value !== 'ANY' && value !== 'EQUALS' && value !== 'PREFIX') {
      throw new BadRequestException({ code: 'MATCH_MODE_INVALID', message: `${field} is invalid.` });
    }
    return value;
  }

  private matchValue(mode: PolicyMatchMode, value: unknown, field: string): string | null {
    if (mode === 'ANY') {
      return null;
    }
    const text = this.limitedString(value, field, 64);
    if (!/^[0-9A-Za-z+*#.-]+$/.test(text)) {
      throw new BadRequestException({ code: 'MATCH_VALUE_INVALID', message: `${field} contains invalid characters.` });
    }
    return text;
  }

  private priority(value: unknown): number {
    if (typeof value !== 'number' || !Number.isInteger(value) || value < 1 || value > 10000) {
      throw new BadRequestException({ code: 'PRIORITY_INVALID', message: 'priority must be an integer from 1 to 10000.' });
    }
    return value;
  }

  private status(value: unknown): PolicyStatus {
    if (value !== 'ENABLED' && value !== 'DISABLED') {
      throw new BadRequestException({ code: 'STATUS_INVALID', message: 'Status is invalid.' });
    }
    return value;
  }
}