/* eslint-disable max-lines-per-function -- 申请 / 审批共用字段状态与上限校验，集中便于审计 */
import {
  type ApplyCustomerFieldInput,
  type ApproveCustomerFieldInput,
  CUSTOMER_GEN_FIELD_LIMIT,
  type CustomerField,
  type CustomerFieldListItem,
  type CustomerFieldListQuery,
  ErrorCode,
  type ListResponse,
  ulid,
} from '@lingxi/shared';
import { Inject, Injectable } from '@nestjs/common';
import { Prisma } from '@prisma/client';

import { AppException } from '../../common/errors/app-exception';
import type { ScopeContext } from '../../common/security/scope/scope-context';
import { isCustomerVisible, requireScopeContext } from '../../common/security/scope/scope-context';
import type { PrismaService } from '../../infra/prisma/prisma.service';
import { PRISMA } from '../../infra/tokens';
import { type CustomerFieldRow, toCustomerField } from './client.mapper';

const FIELD_INCLUDE = {
  applicant: { select: { name: true } },
  approver: { select: { name: true } },
} satisfies Prisma.CustomerFieldInclude;

const FIELD_LIST_INCLUDE = {
  ...FIELD_INCLUDE,
  customer: {
    select: {
      id: true,
      name: true,
      shortName: true,
      industry: { include: { parent: true } },
    },
  },
} satisfies Prisma.CustomerFieldInclude;

function industryPath(customer: {
  industry: { name: string; parent: { name: string } | null };
}): string {
  return customer.industry.parent === null
    ? customer.industry.name
    : `${customer.industry.parent.name} / ${customer.industry.name}`;
}

/**
 * 客户级字段（A3-BE-04）：基础字段走 customers.custom_fields（≤10，免审批）；
 * 本表只承载进入生成 / 需要审批的字段（≤5）。
 */
@Injectable()
export class CustomerFieldsService {
  constructor(@Inject(PRISMA) private readonly prisma: PrismaService) {}

  async list(
    query: CustomerFieldListQuery,
    scopeInput: ScopeContext | null,
  ): Promise<ListResponse<CustomerFieldListItem>> {
    const scope = requireScopeContext(scopeInput);
    const rows = await this.prisma.customerField.findMany({
      where: {
        customer: {
          deletedAt: null,
          ...(scope.customerIds === null ? {} : { id: { in: [...scope.customerIds] } }),
        },
        ...(query.customer_id === undefined ? {} : { customerId: query.customer_id }),
        ...(query.status === 'all'
          ? {}
          : {
              status:
                query.status === 'pending'
                  ? 'PENDING'
                  : query.status === 'active'
                    ? 'ACTIVE'
                    : query.status === 'rejected'
                      ? 'REJECTED'
                      : 'DISABLED',
            }),
      },
      include: FIELD_LIST_INCLUDE,
      orderBy: [{ status: 'asc' }, { appliedAt: 'desc' }],
      take: query.limit + 1,
      ...(query.cursor === undefined ? {} : { cursor: { id: query.cursor }, skip: 1 }),
    });
    const page = rows.slice(0, query.limit);
    const next = rows.length > query.limit ? (page[page.length - 1]?.id ?? null) : null;
    return {
      items: page.map((row) => ({
        ...toCustomerField(row as CustomerFieldRow),
        customerName: row.customer.name,
        customerShortName: row.customer.shortName,
        industryPath: industryPath(row.customer),
      })),
      next_cursor: next,
    };
  }

  async listByCustomer(
    customerId: string,
    scopeInput: ScopeContext | null,
  ): Promise<CustomerField[]> {
    const scope = requireScopeContext(scopeInput);
    if (!isCustomerVisible(scope, customerId)) {
      throw new AppException({ code: ErrorCode.NOT_FOUND, message: '客户不存在' });
    }
    const rows = await this.prisma.customerField.findMany({
      where: { customerId, customer: { deletedAt: null } },
      include: FIELD_INCLUDE,
      orderBy: [{ status: 'asc' }, { appliedAt: 'desc' }],
    });
    return rows.map((row) => toCustomerField(row as CustomerFieldRow));
  }

  async apply(
    customerId: string,
    input: ApplyCustomerFieldInput,
    actorId: string,
    scopeInput: ScopeContext | null,
  ): Promise<CustomerField> {
    const scope = requireScopeContext(scopeInput);
    if (!isCustomerVisible(scope, customerId)) {
      throw new AppException({ code: ErrorCode.NOT_FOUND, message: '客户不存在' });
    }
    const customer = await this.prisma.customer.findFirst({
      where: { id: customerId, deletedAt: null },
      select: { id: true, status: true },
    });
    if (customer === null) {
      throw new AppException({ code: ErrorCode.NOT_FOUND, message: '客户不存在' });
    }
    if (customer.status !== 'ACTIVE') {
      throw new AppException({
        code: ErrorCode.STATE_NOT_ALLOWED,
        message: customer.status === 'PAUSED' ? '客户已暂停，字段只读' : '客户已结束，字段只读归档',
      });
    }
    const duplicate = await this.prisma.customerField.findUnique({
      where: { customerId_code: { customerId, code: input.code } },
      select: { id: true },
    });
    if (duplicate !== null) {
      throw new AppException({
        code: ErrorCode.DUPLICATE_SUBMIT,
        message: '该客户下字段编码已存在',
      });
    }
    if (input.entersGeneration) {
      const used = await this.genUsedCount(customerId);
      if (used >= CUSTOMER_GEN_FIELD_LIMIT) {
        throw new AppException({
          code: ErrorCode.PARAM_INVALID,
          message: `进入生成字段已达 ${CUSTOMER_GEN_FIELD_LIMIT} 个上限，请先停用或驳回其他字段`,
        });
      }
    }
    const id = ulid();
    await this.prisma.customerField.create({
      data: {
        id,
        customerId,
        name: input.name,
        code: input.code,
        type: input.type,
        options: input.options,
        purpose: input.purpose,
        entersGeneration: input.entersGeneration,
        status: input.entersGeneration ? 'PENDING' : 'ACTIVE',
        applicantUserId: actorId,
        ...(input.entersGeneration ? {} : { approvedAt: new Date(), approverUserId: actorId }),
      },
    });
    const row = await this.prisma.customerField.findUniqueOrThrow({
      where: { id },
      include: FIELD_INCLUDE,
    });
    return toCustomerField(row);
  }

  async approve(
    id: string,
    input: ApproveCustomerFieldInput,
    actorId: string,
    scopeInput: ScopeContext | null,
  ): Promise<CustomerField> {
    const scope = requireScopeContext(scopeInput);
    const existing = await this.prisma.customerField.findUnique({
      where: { id },
      include: { customer: { select: { id: true, deletedAt: true } } },
    });
    // eslint-disable-next-line @typescript-eslint/prefer-optional-chain -- 保留显式 null 分支，跨客户统一 404
    if (existing === null || existing.customer.deletedAt !== null) {
      throw new AppException({ code: ErrorCode.NOT_FOUND, message: '字段申请不存在' });
    }
    if (!isCustomerVisible(scope, existing.customerId)) {
      throw new AppException({ code: ErrorCode.NOT_FOUND, message: '字段申请不存在' });
    }
    if (existing.status !== 'PENDING') {
      throw new AppException({ code: ErrorCode.STATE_NOT_ALLOWED, message: '该申请已处理' });
    }
    if (input.decision === 'approve' && existing.entersGeneration) {
      const used = await this.genUsedCount(existing.customerId, id);
      if (used >= CUSTOMER_GEN_FIELD_LIMIT) {
        throw new AppException({
          code: ErrorCode.PARAM_INVALID,
          message: `进入生成字段已达 ${CUSTOMER_GEN_FIELD_LIMIT} 个上限，审批后仍超限`,
        });
      }
    }
    await this.prisma.customerField.update({
      where: { id },
      data:
        input.decision === 'approve'
          ? {
              status: 'ACTIVE',
              approverUserId: actorId,
              approvedAt: new Date(),
              rejectReason: null,
            }
          : {
              status: 'REJECTED',
              approverUserId: actorId,
              approvedAt: new Date(),
              rejectReason: input.reason ?? '',
            },
    });
    const row = await this.prisma.customerField.findUniqueOrThrow({
      where: { id },
      include: FIELD_INCLUDE,
    });
    return toCustomerField(row);
  }

  private async genUsedCount(customerId: string, excludeId?: string): Promise<number> {
    return this.prisma.customerField.count({
      where: {
        customerId,
        entersGeneration: true,
        status: { not: 'REJECTED' },
        ...(excludeId === undefined ? {} : { id: { not: excludeId } }),
      },
    });
  }
}