import {
  BadRequestException,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import type {
  CreateDealRequest,
  DealDto,
  DealLineItemInput,
  MoveDealRequest,
  UpdateDealRequest,
} from '@mento/shared';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import { PipelinesService } from './pipelines.service';
import { toJsonCustomFields } from '../common/custom-fields';
import { NotificationsService } from '../notifications/notifications.service';
import { AutomationsService } from '../automations/automations.service';
import { MessageAutomationsService } from '../message-automations/message-automations.service';
import { WebhooksService } from '../public-api/webhooks.service';
import {
  type Actor,
  canReassignOwner,
  dealAccessWhere,
  ownerWhere,
  resolveOwnerId,
} from '../common/record-scope';

const dealInclude = {
  person: { select: { id: true, firstName: true, lastName: true } },
  company: { select: { id: true, name: true } },
  owner: { select: { id: true, fullName: true } },
  createdBy: { select: { id: true, fullName: true } },
  assignees: { select: { id: true, fullName: true } },
  lineItems: { orderBy: { position: 'asc' as const } },
} satisfies Prisma.DealInclude;

type DealActor = Pick<
  Actor,
  'userId' | 'role' | 'dataVisibility' | 'visibleUserIds'
>;

@Injectable()
export class DealsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly pipelines: PipelinesService,
    private readonly notifications: NotificationsService,
    private readonly automations: AutomationsService,
    private readonly messageAutomations: MessageAutomationsService,
    private readonly webhooks: WebhooksService,
  ) {}

  async get(
    organizationId: string,
    id: string,
    actor: DealActor,
  ): Promise<DealDto> {
    const row = await this.findDeal(organizationId, id, actor);
    return this.pipelines.toDealDto(row);
  }

  async create(
    organizationId: string,
    actor: DealActor,
    dto: CreateDealRequest,
  ): Promise<DealDto> {
    const pipeline =
      dto.pipelineId != null
        ? await this.prisma.pipeline.findFirst({
            where: { id: dto.pipelineId, organizationId },
            include: { stages: { orderBy: { position: 'asc' } } },
          })
        : null;

    const resolvedPipeline =
      pipeline ??
      (await this.prisma.pipeline.findFirst({
        where: { organizationId, isDefault: true },
        include: { stages: { orderBy: { position: 'asc' } } },
      }));

    if (!resolvedPipeline) {
      await this.pipelines.ensureDefaultPipeline(organizationId);
      return this.create(organizationId, actor, dto);
    }

    const stage =
      (dto.stageId
        ? resolvedPipeline.stages.find((s) => s.id === dto.stageId)
        : resolvedPipeline.stages.find((s) => !s.isWon && !s.isLost)) ??
      resolvedPipeline.stages[0];

    if (!stage) {
      throw new BadRequestException('مسیر فروش مرحله‌ای ندارد');
    }

    await this.assertLinks(organizationId, actor, dto.personId, dto.companyId);
    if (dto.lineItems?.length) {
      await this.assertProducts(organizationId, dto.lineItems);
    }
    const assigneeIds = await this.normalizeAssigneeIds(
      organizationId,
      dto.assigneeIds,
    );

    const maxPos = await this.prisma.deal.aggregate({
      where: { organizationId, stageId: stage.id },
      _max: { position: true },
    });

    const status = stage.isWon ? 'won' : stage.isLost ? 'lost' : 'open';
    const amountFromLines = sumLineItems(dto.lineItems);
    const currency =
      dto.lineItems?.[0]?.currency?.trim() ||
      (dto.currency ?? 'IRR').trim() ||
      'IRR';

    const created = await this.prisma.deal.create({
      data: {
        organizationId,
        pipelineId: resolvedPipeline.id,
        stageId: stage.id,
        title: dto.title.trim(),
        amount:
          amountFromLines != null
            ? new Prisma.Decimal(amountFromLines)
            : dto.amount == null || Number.isNaN(Number(dto.amount))
              ? null
              : new Prisma.Decimal(dto.amount),
        currency,
        status,
        source: emptyToNull(dto.source),
        notes: emptyToNull(dto.notes),
        tags: normalizeTags(dto.tags),
        isStale: dto.isStale ?? false,
        isRotten: dto.isRotten ?? false,
        customFields: toJsonCustomFields(dto.customFields),
        expectedCloseAt: dto.expectedCloseAt
          ? new Date(dto.expectedCloseAt)
          : null,
        code: emptyToNull(dto.code),
        probability: normalizeProbability(dto.probability),
        sourceDetail: emptyToNull(dto.sourceDetail),
        referrer: emptyToNull(dto.referrer),
        lostReason: emptyToNull(dto.lostReason),
        lostNote: emptyToNull(dto.lostNote),
        closedAt: dto.closedAt
          ? new Date(dto.closedAt)
          : status !== 'open'
            ? new Date()
            : null,
        createdById: actor.userId,
        personId: emptyToNull(dto.personId ?? null),
        companyId: emptyToNull(dto.companyId ?? null),
        ownerId: resolveOwnerId(actor, dto.ownerId),
        position: (maxPos._max.position ?? -1) + 1,
        ...(assigneeIds.length
          ? { assignees: { connect: assigneeIds.map((id) => ({ id })) } }
          : {}),
        ...(dto.lineItems?.length
          ? {
              lineItems: {
                create: dto.lineItems.map((item, index) => ({
                  productId: emptyToNull(item.productId ?? null),
                  name: item.name.trim(),
                  quantity: new Prisma.Decimal(item.quantity),
                  unitPrice: new Prisma.Decimal(item.unitPrice),
                  currency: (item.currency ?? currency).trim() || 'IRR',
                  position: index,
                })),
              },
            }
          : {}),
      },
      include: dealInclude,
    });

    const createdCtx = {
      organizationId,
      entityType: 'deal' as const,
      entityId: created.id,
      title: created.title,
      personId: created.personId,
      companyId: created.companyId,
      dealId: created.id,
      ownerId: created.ownerId,
    };
    await this.automations.runTrigger('deal_created', createdCtx);
    await this.messageAutomations.onEvent('deal_created', createdCtx);
    this.webhooks.emit(organizationId, 'deal.created', {
      id: created.id,
      title: created.title,
      status: created.status,
      amount: created.amount == null ? null : Number(created.amount),
      currency: created.currency,
      stageId: created.stageId,
      pipelineId: created.pipelineId,
    });

    return this.pipelines.toDealDto(created);
  }

  async update(
    organizationId: string,
    id: string,
    actor: DealActor,
    dto: UpdateDealRequest,
  ): Promise<DealDto> {
    await this.ensureExists(organizationId, id, actor);
    await this.assertLinks(organizationId, actor, dto.personId, dto.companyId);
    if (dto.lineItems) {
      await this.assertProducts(organizationId, dto.lineItems);
    }

    const data: Prisma.DealUncheckedUpdateInput = {};
    if (dto.title !== undefined) data.title = dto.title.trim();
    if ('amount' in dto && dto.lineItems === undefined) {
      data.amount =
        dto.amount == null || Number.isNaN(Number(dto.amount))
          ? null
          : new Prisma.Decimal(dto.amount);
    }
    if (dto.currency !== undefined && dto.lineItems === undefined) {
      data.currency = dto.currency.trim() || 'IRR';
    }
    if ('source' in dto) data.source = emptyToNull(dto.source);
    if ('notes' in dto) data.notes = emptyToNull(dto.notes);
    if (dto.tags !== undefined) data.tags = normalizeTags(dto.tags);
    if (dto.isStale !== undefined) data.isStale = dto.isStale;
    if (dto.isRotten !== undefined) data.isRotten = dto.isRotten;
    if ('customFields' in dto) {
      data.customFields = toJsonCustomFields(dto.customFields);
    }
    if ('lostReason' in dto) data.lostReason = emptyToNull(dto.lostReason);
    if ('lostNote' in dto) data.lostNote = emptyToNull(dto.lostNote);
    if ('code' in dto) data.code = emptyToNull(dto.code);
    if ('probability' in dto) data.probability = normalizeProbability(dto.probability);
    if ('sourceDetail' in dto) data.sourceDetail = emptyToNull(dto.sourceDetail);
    if ('referrer' in dto) data.referrer = emptyToNull(dto.referrer);
    if ('closedAt' in dto) data.closedAt = dto.closedAt ? new Date(dto.closedAt) : null;
    if ('expectedCloseAt' in dto) {
      data.expectedCloseAt = dto.expectedCloseAt
        ? new Date(dto.expectedCloseAt)
        : null;
    }
    if ('personId' in dto) data.personId = emptyToNull(dto.personId ?? null);
    if ('companyId' in dto) data.companyId = emptyToNull(dto.companyId ?? null);
    if (dto.ownerId !== undefined && canReassignOwner(actor.role)) {
      data.ownerId = resolveOwnerId(actor, dto.ownerId);
    }

    let assigneeConnect: { id: string }[] | undefined;
    if (dto.assigneeIds !== undefined) {
      const assigneeIds = await this.normalizeAssigneeIds(
        organizationId,
        dto.assigneeIds,
      );
      assigneeConnect = assigneeIds.map((uid) => ({ id: uid }));
    }

    if (dto.lineItems !== undefined) {
      const total = sumLineItems(dto.lineItems);
      data.amount =
        total == null ? null : new Prisma.Decimal(total);
      if (dto.lineItems[0]?.currency) {
        data.currency = dto.lineItems[0].currency.trim() || 'IRR';
      }
    }

    await this.prisma.$transaction(async (tx) => {
      if (dto.lineItems !== undefined) {
        await tx.dealLineItem.deleteMany({ where: { dealId: id } });
        if (dto.lineItems.length) {
          const currency =
            (typeof data.currency === 'string' ? data.currency : null) ||
            'IRR';
          await tx.dealLineItem.createMany({
            data: dto.lineItems.map((item, index) => ({
              dealId: id,
              productId: emptyToNull(item.productId ?? null),
              name: item.name.trim(),
              quantity: new Prisma.Decimal(item.quantity),
              unitPrice: new Prisma.Decimal(item.unitPrice),
              currency: (item.currency ?? currency).trim() || 'IRR',
              position: index,
            })),
          });
        }
      }
      await tx.deal.update({
        where: { id },
        data: {
          ...data,
          ...(assigneeConnect
            ? { assignees: { set: assigneeConnect } }
            : {}),
        },
      });
    });

    const updated = await this.get(organizationId, id, actor);
    this.webhooks.emit(organizationId, 'deal.updated', {
      id: updated.id,
      title: updated.title,
      status: updated.status,
      amount: updated.amount,
      currency: updated.currency,
      stageId: updated.stageId,
      pipelineId: updated.pipelineId,
    });
    return updated;
  }

  async move(
    organizationId: string,
    id: string,
    actor: DealActor,
    dto: MoveDealRequest,
  ): Promise<DealDto> {
    const deal = await this.prisma.deal.findFirst({
      where: { id, organizationId, ...dealAccessWhere(actor) },
      select: {
        id: true,
        title: true,
        pipelineId: true,
        stageId: true,
        ownerId: true,
        status: true,
        personId: true,
        companyId: true,
      },
    });
    if (!deal) throw new NotFoundException('معامله پیدا نشد');

    const stage = await this.prisma.pipelineStage.findFirst({
      where: { id: dto.stageId, pipelineId: deal.pipelineId },
    });
    if (!stage) {
      throw new BadRequestException('مرحله در این مسیر فروش معتبر نیست');
    }

    const status = stage.isWon ? 'won' : stage.isLost ? 'lost' : 'open';
    const position =
      dto.position ??
      ((
        await this.prisma.deal.aggregate({
          where: { organizationId, stageId: stage.id, NOT: { id } },
          _max: { position: true },
        })
      )._max.position ?? -1) + 1;

    const row = await this.prisma.deal.update({
      where: { id },
      data: {
        stageId: stage.id,
        position,
        status,
        lostReason: stage.isLost ? undefined : null,
        ...(status !== deal.status
          ? { closedAt: status === 'open' ? null : new Date() }
          : {}),
      },
      include: dealInclude,
    });

    if (deal.ownerId && deal.stageId !== stage.id) {
      await this.notifications.create({
        organizationId,
        userId: deal.ownerId,
        type: 'deal_moved',
        title: 'جابه‌جایی معامله در مسیر فروش',
        body: `«${deal.title}» به مرحله «${stage.name}» منتقل شد`,
        link: `/deals/${deal.id}`,
        entityType: 'deal',
        entityId: deal.id,
      });
    }

    if (deal.stageId !== stage.id) {
      const ctx = {
        organizationId,
        entityType: 'deal' as const,
        entityId: deal.id,
        title: deal.title,
        personId: deal.personId,
        companyId: deal.companyId,
        dealId: deal.id,
        ownerId: deal.ownerId,
      };
      await this.automations.runTrigger('deal_stage_changed', ctx);
      await this.messageAutomations.onEvent('deal_stage_changed', ctx);
      if (status === 'won' && deal.status !== 'won') {
        await this.automations.runTrigger('deal_won', ctx);
        await this.messageAutomations.onEvent('deal_won', ctx);
        this.webhooks.emit(organizationId, 'deal.won', {
          id: deal.id,
          title: deal.title,
          stageId: dto.stageId,
        });
      }
      if (status === 'lost' && deal.status !== 'lost') {
        await this.automations.runTrigger('deal_lost', ctx);
        await this.messageAutomations.onEvent('deal_lost', ctx);
        this.webhooks.emit(organizationId, 'deal.lost', {
          id: deal.id,
          title: deal.title,
          stageId: dto.stageId,
        });
      }
    }

    return this.pipelines.toDealDto(row);
  }

  async remove(
    organizationId: string,
    id: string,
    actor: DealActor,
  ): Promise<void> {
    await this.ensureExists(organizationId, id, actor);
    await this.prisma.deal.delete({ where: { id } });
  }

  private async ensureExists(
    organizationId: string,
    id: string,
    actor: DealActor,
  ) {
    const found = await this.prisma.deal.findFirst({
      where: { id, organizationId, ...dealAccessWhere(actor) },
      select: { id: true },
    });
    if (!found) throw new NotFoundException('معامله پیدا نشد');
  }

  private async findDeal(
    organizationId: string,
    id: string,
    actor: DealActor,
  ) {
    const row = await this.prisma.deal.findFirst({
      where: { id, organizationId, ...dealAccessWhere(actor) },
      include: dealInclude,
    });
    if (!row) throw new NotFoundException('معامله پیدا نشد');
    return row;
  }

  private async normalizeAssigneeIds(
    organizationId: string,
    raw?: string[] | null,
  ): Promise<string[]> {
    const ids = [
      ...new Set((raw ?? []).map((id) => id.trim()).filter(Boolean)),
    ];
    if (!ids.length) return [];
    const count = await this.prisma.user.count({
      where: { organizationId, id: { in: ids }, isActive: true },
    });
    if (count !== ids.length) {
      throw new BadRequestException('یکی از مسئولان انتخاب‌شده معتبر نیست');
    }
    return ids;
  }

  private async assertProducts(
    organizationId: string,
    items: DealLineItemInput[],
  ) {
    const ids = [
      ...new Set(
        items
          .map((i) => emptyToNull(i.productId ?? null))
          .filter((id): id is string => Boolean(id)),
      ),
    ];
    if (!ids.length) return;
    const count = await this.prisma.product.count({
      where: { organizationId, id: { in: ids } },
    });
    if (count !== ids.length) {
      throw new BadRequestException('یکی از محصولات انتخاب‌شده معتبر نیست');
    }
  }

  private async assertLinks(
    organizationId: string,
    actor: DealActor,
    personId?: string | null,
    companyId?: string | null,
  ) {
    const pId = emptyToNull(personId ?? null);
    const cId = emptyToNull(companyId ?? null);
    const scope = ownerWhere(actor);
    if (pId) {
      const person = await this.prisma.person.findFirst({
        where: { id: pId, organizationId, ...scope },
        select: { id: true },
      });
      if (!person) throw new BadRequestException('شخص انتخاب‌شده معتبر نیست');
    }
    if (cId) {
      const company = await this.prisma.company.findFirst({
        where: { id: cId, organizationId, ...scope },
        select: { id: true },
      });
      if (!company) throw new BadRequestException('شرکت انتخاب‌شده معتبر نیست');
    }
  }
}

function emptyToNull(value?: string | null): string | null {
  if (value == null) return null;
  const trimmed = value.trim();
  return trimmed.length ? trimmed : null;
}

function normalizeProbability(value?: number | null): number | null {
  if (value == null || Number.isNaN(Number(value))) return null;
  return Math.max(0, Math.min(100, Math.round(Number(value))));
}

function normalizeTags(tags?: string[]): string[] {
  if (!tags?.length) return [];
  const seen = new Set<string>();
  const out: string[] = [];
  for (const raw of tags) {
    const tag = raw.trim();
    if (!tag) continue;
    const key = tag.toLowerCase();
    if (seen.has(key)) continue;
    seen.add(key);
    out.push(tag.slice(0, 40));
  }
  return out.slice(0, 20);
}

function sumLineItems(items?: DealLineItemInput[]): number | null {
  if (!items?.length) return null;
  return items.reduce(
    (sum, item) => sum + Number(item.quantity) * Number(item.unitPrice),
    0,
  );
}