import {
  BadRequestException,
  ForbiddenException,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import type { AuthUser } from '../common/decorators/current-user.decorator';
import { BIZ_TYPE } from '../bidding/bid-workflow';
import { SealService } from '../seal/seal.service';
import { CONTRACT_BIZ, CONTRACT_STATUS, canAccessContract, canEditContract, milestoneSumOk } from './contract-workflow';
import { nextBizNo } from '../system/numbering';
import { assertCanSeeOwner, ownerScope, withAnd } from '../common/data-scope';
import { BUDGET_CATEGORY, PROJECT_STATUS, splitEven } from '../project/project-workflow';

const USER_SELECT = { id: true, displayName: true, username: true };

const DETAIL_INCLUDE = {
  bidCase: { select: { id: true, bidNo: true, name: true, status: true, quoteAmount: true, party: { select: { name: true } } } },
  legalEntity: true,
  createdBy: { select: USER_SELECT },
  milestones: { include: { invoice: true }, orderBy: { dueAt: 'asc' as const } },
  reviewers: {
    include: { user: { select: USER_SELECT } },
    orderBy: { decidedAt: 'asc' as const },
  },
  actionLogs: {
    include: { actor: { select: USER_SELECT } },
    orderBy: { createdAt: 'asc' as const },
  },
  sealRequests: { orderBy: { createdAt: 'desc' as const } },
  invoices: true,
  projects: true,
};

type Tx = Prisma.TransactionClient;

export type CreateContractInput = {
  bidCaseId?: string;
  legalEntityId?: string;
  amount: number;
  name?: string;
  partyA?: string;
  partyB?: string;
  remark?: string;
  contractNo?: string;
  kind?: string;
};

export type UpdateContractInput = {
  name?: string;
  amount?: number;
  partyA?: string;
  partyB?: string;
  remark?: string;
  nasPath?: string;
  contractNo?: string;
};

function officialContractNo(raw?: string | null) {
  const n = (raw || '').trim();
  if (!n || n === '待填' || n === '-' || n === '—') return '';
  return n;
}

export type MilestoneInput = {
  name: string;
  ratio: number;
  dueAt?: string;
  trigger?: string;
};

export type ReviewInput = {
  result: 'APPROVED' | 'REJECTED';
  comment?: string;
};

export type SealInput = {
  sealType: string;
  reason: string;
  takeOut?: boolean;
  returnAt?: string;
};

@Injectable()
export class ContractService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly seals: SealService,
  ) {}

  assertAccess(user: AuthUser) {
    if (!canAccessContract(user.roles, user.permissions)) {
      throw new ForbiddenException('无权访问合同管理');
    }
  }

  async list(user: AuthUser, page: number, pageSize: number, keyword?: string, bucket?: string) {
    this.assertAccess(user);
    const where: Prisma.ContractWhereInput = { tenantId: '1' };
    if (bucket === 'tender' || bucket === 'bid' || bucket === 'approval') {
      where.OR = [{ kind: 'TENDER' }, { bidCaseId: { not: null } }];
    }
    if (bucket === 'direct') {
      where.kind = 'DIRECT';
    }
    if (bucket === 'incremental' || bucket === 'other') {
      where.kind = 'OTHER';
      where.bidCaseId = null;
    }
    if (keyword) {
      where.AND = [
        {
          OR: [
            { name: { contains: keyword } },
            { contractNo: { contains: keyword } },
            { partyA: { contains: keyword } },
            { partyB: { contains: keyword } },
          ],
        },
      ];
    }
    const scoped = withAnd(where, (await ownerScope(this.prisma, user, 'createdById')) as Record<string, unknown>);
    const [items, total] = await this.prisma.$transaction([
      this.prisma.contract.findMany({
        where: scoped,
        include: {
          bidCase: {
            select: {
              id: true,
              bidNo: true,
              externalNo: true,
              name: true,
              party: { select: { name: true } },
              createdBy: { select: USER_SELECT },
            },
          },
          legalEntity: true,
          createdBy: { select: USER_SELECT },
          projects: { select: { id: true, projectNo: true, status: true } },
          milestones: true,
        },
        orderBy: { createdAt: 'desc' },
        skip: (page - 1) * pageSize,
        take: pageSize,
      }),
      this.prisma.contract.count({ where: scoped }),
    ]);
    return { items, page, pageSize, total };
  }

  async get(id: string, user: AuthUser) {
    this.assertAccess(user);
    const row = await this.prisma.contract.findFirst({
      where: { id, tenantId: '1' },
      include: DETAIL_INCLUDE,
    });
    if (!row) throw new NotFoundException('合同不存在');
    await assertCanSeeOwner(this.prisma, user, row.createdById);
    const files = await this.prisma.fileAsset.findMany({
      where: { tenantId: '1', bizId: id, bizType: { startsWith: 'CONTRACT' } },
      orderBy: { createdAt: 'asc' },
    });
    return { ...row, files, myActions: this.myActions(row, user) };
  }

  async createIncremental(dto: CreateContractInput, user: AuthUser) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) {
      throw new ForbiddenException('无权起草合同');
    }
    const name = dto.name?.trim();
    if (!name) throw new BadRequestException('请填写合同名称');
    if (!dto.amount || dto.amount <= 0) throw new BadRequestException('请填写合同金额');
    const kind = dto.kind === 'TENDER' || dto.kind === 'DIRECT' ? dto.kind : 'OTHER';
    const contract = await this.prisma.$transaction(async (tx) => {
      const entity = dto.legalEntityId
        ? await tx.legalEntity.findFirst({ where: { id: dto.legalEntityId, tenantId: '1' } })
        : (await tx.legalEntity.findFirst({ where: { tenantId: '1', isDefault: true } })) ||
          (await tx.legalEntity.findFirst({ where: { tenantId: '1' } }));
      if (dto.legalEntityId && !entity) throw new NotFoundException('我方主体不存在');
      if (kind === 'TENDER' && dto.bidCaseId) {
        const bid = await tx.bidCase.findFirst({ where: { id: dto.bidCaseId, tenantId: '1' } });
        if (!bid) throw new NotFoundException('投标事项不存在');
        const existing = await tx.contract.findFirst({
          where: {
            bidCaseId: bid.id,
            status: { in: [CONTRACT_STATUS.DRAFT, CONTRACT_STATUS.PENDING, CONTRACT_STATUS.APPROVED] },
          },
        });
        if (existing) {
          throw new BadRequestException('该中标事项已自动生成合同草稿，请到合同管理完善后提交审批');
        }
      }
      const contractNo = officialContractNo(dto.contractNo) || null;
      if (contractNo) {
        const clash = await tx.contract.findFirst({ where: { tenantId: '1', contractNo } });
        if (clash) throw new BadRequestException('该合同编号已存在');
      }
      const created = await tx.contract.create({
        data: {
          tenantId: '1',
          contractNo,
          name,
          kind,
          bidCaseId: kind === 'TENDER' ? dto.bidCaseId || undefined : undefined,
          legalEntityId: entity?.id,
          amount: dto.amount,
          partyA: dto.partyA?.trim() || undefined,
          partyB: dto.partyB?.trim() || entity?.name || undefined,
          remark: dto.remark,
          status: CONTRACT_STATUS.DRAFT,
          createdById: user.id,
        },
      });
      const label = kind === 'TENDER' ? '投标合同' : kind === 'DIRECT' ? '直签合同' : '其他合同';
      await this.log(tx, created.id, user.id, 'CREATE', undefined, CONTRACT_STATUS.DRAFT, `新建${label}`);
      return created;
    });
    return this.get(contract.id, user);
  }

  async createFromBid(dto: CreateContractInput, user: AuthUser) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) {
      throw new ForbiddenException('无权起草合同');
    }
    if (!dto.bidCaseId) throw new BadRequestException('请选择投标事项');
    if (!dto.amount || dto.amount <= 0) {
      throw new BadRequestException('请填写合同金额');
    }
    const contract = await this.prisma.$transaction(async (tx) => {
      const bid = await tx.bidCase.findFirst({
        where: { id: dto.bidCaseId, tenantId: '1' },
        include: { party: true, legalEntity: true },
      });
      if (!bid) throw new NotFoundException('投标事项不存在');
      if (bid.status !== 'WON') {
        throw new BadRequestException('只有中标事项可以转合同');
      }
      const existing = await tx.contract.findFirst({
        where: {
          bidCaseId: bid.id,
          status: { in: [CONTRACT_STATUS.DRAFT, CONTRACT_STATUS.PENDING, CONTRACT_STATUS.APPROVED] },
        },
      });
      if (existing) {
        throw new BadRequestException('该中标事项已自动生成合同草稿，请到合同管理完善后提交审批');
      }
      const contractNo = officialContractNo(dto.contractNo) || null;
      if (contractNo) {
        const clash = await tx.contract.findFirst({ where: { tenantId: '1', contractNo } });
        if (clash) throw new BadRequestException('该合同编号已存在');
      }
      const created = await tx.contract.create({
        data: {
          tenantId: '1',
          contractNo,
          name: dto.name?.trim() || bid.name,
          bidCaseId: bid.id,
          legalEntityId: bid.legalEntityId,
          amount: dto.amount,
          partyA: dto.partyA?.trim() || bid.party?.name || undefined,
          partyB: dto.partyB?.trim() || bid.legalEntity?.name || undefined,
          remark: dto.remark,
          kind: 'TENDER',
          status: CONTRACT_STATUS.DRAFT,
          createdById: user.id,
        },
      });
      await tx.todoTask.updateMany({
        where: {
          status: 'OPEN',
          bizType: BIZ_TYPE.CONVERT_CONTRACT,
          bizId: { in: [bid.id, created.id] },
        },
        data: { status: 'DONE' },
      });
      await this.log(tx, created.id, user.id, 'CREATE', undefined, CONTRACT_STATUS.DRAFT, `由 ${bid.bidNo} 转合同`);
      return created;
    });
    return this.get(contract.id, user);
  }

  async update(id: string, user: AuthUser, dto: UpdateContractInput) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) throw new ForbiddenException('无权修改合同');
    const row = await this.require(id);
    if (row.status !== CONTRACT_STATUS.DRAFT && row.status !== CONTRACT_STATUS.REJECTED) {
      throw new BadRequestException('当前状态不能修改');
    }
    const contractNo = dto.contractNo === undefined ? undefined : officialContractNo(dto.contractNo) || null;
    if (contractNo) {
      const clash = await this.prisma.contract.findFirst({
        where: { tenantId: '1', contractNo, id: { not: id } },
      });
      if (clash) throw new BadRequestException('该合同编号已存在');
    }
    await this.prisma.contract.update({
      where: { id },
      data: {
        name: dto.name?.trim() || undefined,
        amount: dto.amount,
        partyA: dto.partyA?.trim() || undefined,
        partyB: dto.partyB?.trim() || undefined,
        remark: dto.remark,
        nasPath: dto.nasPath,
        contractNo,
        status: CONTRACT_STATUS.DRAFT,
      },
    });
    await this.prisma.contractActionLog.create({
      data: {
        contractId: id,
        actorId: user.id,
        action: 'UPDATE',
        fromStatus: row.status,
        toStatus: CONTRACT_STATUS.DRAFT,
      },
    });
    return this.get(id, user);
  }

  async replaceMilestones(id: string, user: AuthUser, items: MilestoneInput[]) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) throw new ForbiddenException('无权修改收款条款');
    const row = await this.require(id);
    if (row.status !== CONTRACT_STATUS.DRAFT && row.status !== CONTRACT_STATUS.REJECTED) {
      throw new BadRequestException('当前状态不能改收款条款');
    }
    if (!items?.length) throw new BadRequestException('请至少填写一条收款条款');
    const ratios = items.map((i) => Number(i.ratio));
    if (ratios.some((n) => !Number.isFinite(n) || n <= 0)) {
      throw new BadRequestException('比例必须大于 0');
    }
    if (!milestoneSumOk(ratios)) {
      throw new BadRequestException('收款条款比例合计必须为 100%');
    }
    await this.prisma.$transaction(async (tx) => {
      await tx.paymentMilestone.deleteMany({ where: { contractId: id } });
      await tx.paymentMilestone.createMany({
        data: items.map((i) => ({
          contractId: id,
          name: i.name,
          ratio: i.ratio,
          dueAt: i.dueAt ? new Date(i.dueAt) : null,
          trigger: i.trigger || null,
        })),
      });
      await tx.contract.update({
        where: { id },
        data: { status: CONTRACT_STATUS.DRAFT },
      });
      await this.log(tx, id, user.id, 'MILESTONES', row.status, CONTRACT_STATUS.DRAFT, `更新 ${items.length} 条收款条款`);
    });
    return this.get(id, user);
  }

  async createSeal(id: string, user: AuthUser, dto: SealInput) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) throw new ForbiddenException('无权申请用章');
    if (!dto.sealType?.trim() || !dto.reason?.trim()) {
      throw new BadRequestException('请填写印章类型和事由');
    }
    const row = await this.require(id);
    if (row.status === CONTRACT_STATUS.APPROVED) {
      throw new BadRequestException('合同已通过，用章请走证照用章模块补登记');
    }
    await this.prisma.sealRequest.create({
      data: {
        tenantId: '1',
        sealType: dto.sealType.trim(),
        reason: dto.reason.trim(),
        contractId: row.id,
        bidCaseId: row.bidCaseId,
        applicantId: user.id,
        takeOut: Boolean(dto.takeOut),
        returnAt: dto.returnAt ? new Date(dto.returnAt) : null,
        status: 'PENDING',
      },
    });
    await this.prisma.contractActionLog.create({
      data: {
        contractId: id,
        actorId: user.id,
        action: 'SEAL_REQUEST',
        comment: `${dto.sealType}：${dto.reason}`,
      },
    });
    return this.get(id, user);
  }

  async submit(id: string, user: AuthUser) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) throw new ForbiddenException('无权提交合同审批');
    await this.prisma.$transaction(async (tx) => {
      const row = await tx.contract.findFirst({
        where: { id, tenantId: '1' },
        include: { milestones: true, sealRequests: true, reviewers: true },
      });
      if (!row) throw new NotFoundException('合同不存在');
      if (row.status !== CONTRACT_STATUS.DRAFT && row.status !== CONTRACT_STATUS.REJECTED) {
        throw new BadRequestException('当前状态不能提交审批');
      }
      if (Number(row.amount) <= 0) throw new BadRequestException('请填写合同金额');
      if (!officialContractNo(row.contractNo)) {
        throw new BadRequestException('请先填写正式合同编号，不要用系统自动号');
      }
      const ratios = row.milestones.map((m) => Number(m.ratio));
      if (!ratios.length || !milestoneSumOk(ratios)) {
        throw new BadRequestException('请先保存合计为 100% 的收款条款');
      }
      if (!row.sealRequests.length) {
        throw new BadRequestException('提交审批前请先申请用章，必须关联本合同');
      }
      const approvers = await tx.user.findMany({
        where: {
          tenantId: '1',
          status: 'ACTIVE',
          roles: { some: { role: { code: { in: ['owner', 'biz_director'] } } } },
        },
      });
      const ids = [...new Set(approvers.map((u) => u.id))];
      if (!ids.length) throw new BadRequestException('没有可审批的企业负责人或商务总监');
      await tx.contract.update({
        where: { id },
        data: { status: CONTRACT_STATUS.PENDING, submittedAt: new Date() },
      });
      await tx.contractReviewer.deleteMany({ where: { contractId: id } });
      await tx.contractReviewer.createMany({
        data: ids.map((userId) => ({ contractId: id, userId })),
      });
      await tx.approvalTask.createMany({
        data: ids.map((assigneeId) => ({
          tenantId: '1',
          title: `合同审批：${row.name}`,
          bizType: CONTRACT_BIZ.APPROVAL,
          bizId: id,
          assigneeId,
        })),
      });
      await tx.todoTask.updateMany({
        where: {
          status: 'OPEN',
          bizType: BIZ_TYPE.CONVERT_CONTRACT,
          bizId: { in: [id, row.bidCaseId].filter(Boolean) as string[] },
        },
        data: { status: 'DONE' },
      });
      await this.log(tx, id, user.id, 'SUBMIT', row.status, CONTRACT_STATUS.PENDING, '提交合同审批（含用章）');
    });
    return this.get(id, user);
  }

  async review(id: string, user: AuthUser, dto: ReviewInput) {
    this.assertAccess(user);
    if (dto.result === 'REJECTED' && !dto.comment?.trim()) {
      throw new BadRequestException('驳回请填写意见');
    }
    await this.prisma.$transaction(async (tx) => {
      const row = await tx.contract.findFirst({
        where: { id, tenantId: '1' },
        include: { reviewers: true, bidCase: { include: { expenses: true, party: { select: { name: true } } } }, sealRequests: true },
      });
      if (!row) throw new NotFoundException('合同不存在');
      if (row.status !== CONTRACT_STATUS.PENDING) {
        throw new BadRequestException('当前不是待审批状态');
      }
      const mine = row.reviewers.find((r) => r.userId === user.id && r.result === 'PENDING');
      if (!mine) throw new ForbiddenException('没有待办的合同审批');
      await tx.contractReviewer.update({
        where: { id: mine.id },
        data: {
          result: dto.result,
          comment: dto.comment?.trim() || null,
          decidedAt: new Date(),
        },
      });
      await tx.approvalTask.updateMany({
        where: {
          bizId: id,
          assigneeId: user.id,
          status: 'PENDING',
          bizType: CONTRACT_BIZ.APPROVAL,
        },
        data: { status: dto.result === 'APPROVED' ? 'APPROVED' : 'REJECTED' },
      });

      if (dto.result === 'REJECTED') {
        await tx.contract.update({
          where: { id },
          data: { status: CONTRACT_STATUS.DRAFT },
        });
        await tx.approvalTask.updateMany({
          where: { bizId: id, status: 'PENDING' },
          data: { status: 'CANCELLED' },
        });
        await tx.contractReviewer.updateMany({
          where: { contractId: id, result: 'PENDING' },
          data: { result: 'CANCELLED' },
        });
        await this.log(tx, id, user.id, 'REJECT', CONTRACT_STATUS.PENDING, CONTRACT_STATUS.DRAFT, dto.comment!.trim());
        return;
      }

      await this.log(tx, id, user.id, 'APPROVE', CONTRACT_STATUS.PENDING, undefined, dto.comment?.trim() || '同意');
      const pending = await tx.contractReviewer.count({
        where: { contractId: id, result: 'PENDING' },
      });
      if (pending > 0) return;

      await this.seals.applyContractApproved(tx, id);
      const presales = (row.bidCase?.expenses || []).reduce(
        (s, e) => s + Number(e.amount),
        0,
      );
      const existingProject = await tx.project.findFirst({ where: { contractId: row.id } });
      const contractAmount = Number(row.amount || 0);
      let project = existingProject;
      if (existingProject) {
        const patch: Prisma.ProjectUpdateInput = {
          presalesCost: presales,
          partyName: row.partyA || row.bidCase?.party?.name || existingProject.partyName,
        };
        if (contractAmount > 0) patch.amount = contractAmount;
        if (existingProject.status === PROJECT_STATUS.NOT_STARTED) {
          patch.status = PROJECT_STATUS.ACTIVE;
        }
        project = await tx.project.update({ where: { id: existingProject.id }, data: patch });
        const budgetCount = await tx.projectBudget.count({ where: { projectId: existingProject.id } });
        if (contractAmount > 0 && budgetCount === 0) {
          const split = splitEven(contractAmount);
          await tx.projectBudget.createMany({
            data: [
              { projectId: existingProject.id, category: BUDGET_CATEGORY.BUSINESS, amount: split.business },
              { projectId: existingProject.id, category: BUDGET_CATEGORY.TECH, amount: split.tech },
            ],
          });
        }
      } else {
        const projectNo = await nextBizNo(tx, 'PRJ', (start) =>
          tx.project.count({ where: { projectNo: { startsWith: start } } }),
        );
        project = await tx.project.create({
          data: {
            tenantId: '1',
            projectNo,
            name: row.name,
            contractId: row.id,
            partyName: row.partyA || row.bidCase?.party?.name || null,
            status: PROJECT_STATUS.ACTIVE,
            presalesCost: presales,
          },
        });
        if (contractAmount > 0) {
          const split = splitEven(contractAmount);
          await tx.projectBudget.createMany({
            data: [
              { projectId: project.id, category: BUDGET_CATEGORY.BUSINESS, amount: split.business },
              { projectId: project.id, category: BUDGET_CATEGORY.TECH, amount: split.tech },
            ],
          });
        }
      }
      if (row.bidCaseId) {
        await tx.expenseClaim.updateMany({
          where: { bidCaseId: row.bidCaseId },
          data: { projectId: project.id },
        });
      }
      await tx.contract.update({
        where: { id },
        data: {
          status: CONTRACT_STATUS.APPROVED,
          approvedAt: new Date(),
          signedAt: new Date(),
        },
      });
      await this.log(
        tx,
        id,
        user.id,
        'APPROVED',
        CONTRACT_STATUS.PENDING,
        CONTRACT_STATUS.APPROVED,
        existingProject
          ? `合同通过，项目 ${project.projectNo} 已在中标时立项，继承售前成本 ${presales}`
          : `立项 ${project.projectNo}，继承售前成本 ${presales}`,
      );
    });
    return this.get(id, user);
  }

  async decideApproval(approvalId: string, user: AuthUser, dto: ReviewInput) {
    const task = await this.prisma.approvalTask.findFirst({
      where: { id: approvalId, tenantId: '1' },
    });
    if (!task) throw new NotFoundException('审批任务不存在');
    if (task.assigneeId !== user.id) throw new ForbiddenException('这不是你的审批');
    if (task.status !== 'PENDING') throw new BadRequestException('该审批已办理');
    if (task.bizType !== CONTRACT_BIZ.APPROVAL || !task.bizId) {
      throw new BadRequestException('不是合同审批');
    }
    return this.review(task.bizId, user, dto);
  }

  async moveKind(id: string, user: AuthUser, kind: string) {
    this.assertAccess(user);
    if (!canEditContract(user.roles)) throw new ForbiddenException('无权调整合同分类');
    const normalized = String(kind || '').trim().toUpperCase();
    if (!['TENDER', 'DIRECT', 'OTHER'].includes(normalized)) {
      throw new BadRequestException('合同分类只能是投标合同、直签合同或其他合同');
    }
    const row = await this.require(id);
    if (row.status !== CONTRACT_STATUS.DRAFT && row.status !== CONTRACT_STATUS.REJECTED) {
      throw new BadRequestException('仅草稿或已驳回合同可以调整分类');
    }
    const updated = await this.prisma.contract.update({ where: { id }, data: { kind: normalized } });
    return this.get(updated.id, user);
  }

  private async require(id: string) {
    const row = await this.prisma.contract.findFirst({ where: { id, tenantId: '1' } });
    if (!row) throw new NotFoundException('合同不存在');
    return row;
  }

  private async log(
    tx: Tx,
    contractId: string,
    actorId: string,
    action: string,
    fromStatus?: string,
    toStatus?: string,
    comment?: string,
  ) {
    await tx.contractActionLog.create({
      data: { contractId, actorId, action, fromStatus, toStatus, comment },
    });
  }

  private myActions(
    row: {
      status: string;
      reviewers: { userId: string; result: string }[];
      milestones: unknown[];
      sealRequests: unknown[];
      projects: unknown[];
    },
    user: AuthUser,
  ) {
    const editable =
      (row.status === CONTRACT_STATUS.DRAFT || row.status === CONTRACT_STATUS.REJECTED) &&
      canEditContract(user.roles);
    return {
      canEdit: editable,
      canSubmit: editable,
      canRequestSeal: editable,
      canReview: Boolean(
        row.status === CONTRACT_STATUS.PENDING &&
          row.reviewers.some((r) => r.userId === user.id && r.result === 'PENDING'),
      ),
    };
  }
}