import {
  BadRequestException,
  Injectable,
  Logger,
  NotFoundException,
} from '@nestjs/common';
import type {
  AutomationAction,
  AutomationConditionField,
  AutomationConditionOp,
  AutomationNotifyChannel,
  AutomationRuleConfig,
  AutomationRuleDto,
  AutomationStep,
  AutomationTrigger,
  CreateAutomationRuleRequest,
  UpdateAutomationRuleRequest,
} from '@mento/shared';
import {
  MAX_AUTOMATION_STEPS,
  automationStepToConfig,
  firstAutomationAction,
  isAutomationCondition,
  normalizeAutomationSteps,
  packAutomationConfig,
} from '@mento/shared';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import { NotificationsService } from '../notifications/notifications.service';
import { LoyaltyService } from '../loyalty/loyalty.service';
import { SmsService } from '../common/sms.service';

export type AutomationContext = {
  organizationId: string;
  entityType: 'deal' | 'ticket';
  entityId: string;
  title: string;
  personId?: string | null;
  companyId?: string | null;
  dealId?: string | null;
  ownerId?: string | null;
  assigneeId?: string | null;
};

type AutomationFacts = {
  amount: number | null;
  hasPerson: boolean;
  hasCompany: boolean;
  ticketPriority: string | null;
};

@Injectable()
export class AutomationsService {
  private readonly logger = new Logger(AutomationsService.name);

  constructor(
    private readonly prisma: PrismaService,
    private readonly notifications: NotificationsService,
    private readonly loyalty: LoyaltyService,
    private readonly sms: SmsService,
  ) {}

  async list(organizationId: string): Promise<AutomationRuleDto[]> {
    const rows = await this.prisma.automationRule.findMany({
      where: { organizationId },
      orderBy: [{ isActive: 'desc' }, { updatedAt: 'desc' }],
    });
    return rows.map((r) => this.toDto(r));
  }

  async create(
    organizationId: string,
    dto: CreateAutomationRuleRequest,
  ): Promise<AutomationRuleDto> {
    const steps = resolveSteps(dto.action, dto.config);
    const action = firstAutomationAction(steps);
    if (!action) throw new BadRequestException('حداقل یک عمل لازم است');
    const row = await this.prisma.automationRule.create({
      data: {
        organizationId,
        name: dto.name.trim(),
        trigger: dto.trigger,
        action,
        isActive: dto.isActive ?? true,
        config: packAutomationConfig(steps) as Prisma.InputJsonValue,
      },
    });
    return this.toDto(row);
  }

  async update(
    organizationId: string,
    id: string,
    dto: UpdateAutomationRuleRequest,
  ): Promise<AutomationRuleDto> {
    const existing = await this.prisma.automationRule.findFirst({
      where: { id, organizationId },
    });
    if (!existing) throw new NotFoundException('قانون پیدا نشد');

    const shouldRewriteChain =
      dto.action !== undefined || dto.config !== undefined;
    const steps = shouldRewriteChain
      ? resolveSteps(
          (dto.action ?? existing.action) as AutomationAction,
          dto.config ?? asConfig(existing.config),
        )
      : null;
    const nextAction = steps ? firstAutomationAction(steps) : null;
    if (steps && !nextAction) {
      throw new BadRequestException('حداقل یک عمل لازم است');
    }

    const row = await this.prisma.automationRule.update({
      where: { id },
      data: {
        ...(dto.name !== undefined ? { name: dto.name.trim() } : {}),
        ...(dto.trigger !== undefined ? { trigger: dto.trigger } : {}),
        ...(dto.isActive !== undefined ? { isActive: dto.isActive } : {}),
        ...(steps && nextAction
          ? {
              action: nextAction,
              config: packAutomationConfig(steps) as Prisma.InputJsonValue,
            }
          : {}),
      },
    });
    return this.toDto(row);
  }

  async remove(organizationId: string, id: string): Promise<void> {
    const existing = await this.prisma.automationRule.findFirst({
      where: { id, organizationId },
    });
    if (!existing) throw new NotFoundException('قانون پیدا نشد');
    await this.prisma.automationRule.delete({ where: { id } });
  }

  async runTrigger(
    trigger: AutomationTrigger,
    ctx: AutomationContext,
  ): Promise<void> {
    const rules = await this.prisma.automationRule.findMany({
      where: {
        organizationId: ctx.organizationId,
        isActive: true,
        trigger,
      },
    });
    const facts = await this.loadFacts(ctx);
    for (const rule of rules) {
      try {
        const config = asConfig(rule.config);
        const steps = normalizeAutomationSteps(
          rule.action as AutomationAction,
          config,
        );
        for (const step of steps) {
          if (isAutomationCondition(step)) {
            if (!matchCondition(step, facts)) break;
            continue;
          }
          if (!step.action) continue;
          await this.execute(step.action, automationStepToConfig(step), ctx);
        }
      } catch {
        // قوانین نباید شکست عملیات اصلی را ایجاد کنند
      }
    }
  }

  private async loadFacts(ctx: AutomationContext): Promise<AutomationFacts> {
    if (ctx.entityType === 'deal') {
      const deal = await this.prisma.deal.findFirst({
        where: { id: ctx.entityId, organizationId: ctx.organizationId },
        select: { amount: true, personId: true, companyId: true },
      });
      return {
        amount: deal?.amount != null ? Number(deal.amount) : null,
        hasPerson: Boolean(deal?.personId ?? ctx.personId),
        hasCompany: Boolean(deal?.companyId ?? ctx.companyId),
        ticketPriority: null,
      };
    }
    const ticket = await this.prisma.ticket.findFirst({
      where: { id: ctx.entityId, organizationId: ctx.organizationId },
      select: { priority: true, personId: true, companyId: true },
    });
    return {
      amount: null,
      hasPerson: Boolean(ticket?.personId ?? ctx.personId),
      hasCompany: Boolean(ticket?.companyId ?? ctx.companyId),
      ticketPriority: ticket?.priority ?? null,
    };
  }

  private async execute(
    action: AutomationAction,
    config: AutomationRuleConfig,
    ctx: AutomationContext,
  ) {
    const title =
      (config.title?.trim() || defaultTitle(action, ctx.title)).slice(0, 200);

    if (action === 'create_activity') {
      const assigneeId =
        config.assigneeId?.trim() ||
        ctx.assigneeId ||
        ctx.ownerId ||
        null;
      await this.prisma.activity.create({
        data: {
          organizationId: ctx.organizationId,
          type: (config.activityType as never) || 'task',
          title,
          description: config.body?.trim() || null,
          personId: ctx.personId ?? null,
          companyId: ctx.companyId ?? null,
          dealId: ctx.dealId ?? (ctx.entityType === 'deal' ? ctx.entityId : null),
          assigneeId,
        },
      });
      if (assigneeId) {
        await this.notifications.create({
          organizationId: ctx.organizationId,
          userId: assigneeId,
          type: 'automation',
          title: 'فعالیت خودکار',
          body: title,
          link:
            ctx.entityType === 'deal'
              ? `/deals/${ctx.entityId}`
              : `/tickets/${ctx.entityId}`,
          entityType: ctx.entityType,
          entityId: ctx.entityId,
        });
      }
      return;
    }

    if (action === 'create_notification') {
      await this.executeNotify(title, config, ctx);
      return;
    }

    if (action === 'add_loyalty_points') {
      const points = Math.max(1, Math.trunc(config.points ?? 100));
      if (!ctx.personId) return;
      await this.loyalty.addPointsByOrg(
        ctx.organizationId,
        ctx.personId,
        points,
      );
    }
  }

  private async executeNotify(
    title: string,
    config: AutomationRuleConfig,
    ctx: AutomationContext,
  ) {
    const channel: AutomationNotifyChannel = config.notifyChannel ?? 'app';
    const wantApp = channel === 'app' || channel === 'both';
    const wantSms = channel === 'sms' || channel === 'both';
    const smsText = (config.body?.trim() || title).slice(0, 160);
    const link =
      ctx.entityType === 'deal'
        ? `/deals/${ctx.entityId}`
        : `/tickets/${ctx.entityId}`;

    if (config.notifyTarget === 'person') {
      if (wantSms) {
        const person = ctx.personId
          ? await this.prisma.person.findFirst({
              where: {
                id: ctx.personId,
                organizationId: ctx.organizationId,
              },
              select: { mobile: true, phone: true },
            })
          : null;
        await this.sendAutomationSms(person?.mobile || person?.phone, smsText);
      }
      return;
    }

    const userId =
      config.notifyUserId?.trim() ||
      ctx.assigneeId ||
      ctx.ownerId ||
      null;
    if (!userId) return;

    if (wantApp) {
      await this.notifications.create({
        organizationId: ctx.organizationId,
        userId,
        type: 'automation',
        title,
        body: config.body?.trim() || ctx.title,
        link,
        entityType: ctx.entityType,
        entityId: ctx.entityId,
      });
    }

    if (wantSms) {
      const user = await this.prisma.user.findFirst({
        where: { id: userId, organizationId: ctx.organizationId },
        select: { mobile: true },
      });
      await this.sendAutomationSms(user?.mobile, smsText);
    }
  }

  private async sendAutomationSms(
    mobile: string | null | undefined,
    text: string,
  ) {
    if (!mobile) {
      this.logger.warn('Automation SMS skipped: no mobile');
      return;
    }
    if (!this.sms.isConfigured()) {
      this.logger.warn('Automation SMS skipped: SMS not configured');
      return;
    }
    const result = await this.sms.sendSmsDetailed(mobile, text);
    if (!result.ok) {
      this.logger.warn(`Automation SMS failed: ${result.reason ?? 'unknown'}`);
    }
  }

  private toDto(row: {
    id: string;
    name: string;
    isActive: boolean;
    trigger: string;
    action: string;
    config: unknown;
    createdAt: Date;
    updatedAt: Date;
  }): AutomationRuleDto {
    return {
      id: row.id,
      name: row.name,
      isActive: row.isActive,
      trigger: row.trigger as AutomationTrigger,
      action: row.action as AutomationAction,
      config: asConfig(row.config),
      createdAt: row.createdAt.toISOString(),
      updatedAt: row.updatedAt.toISOString(),
    };
  }
}

function asConfig(raw: unknown): AutomationRuleConfig {
  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return {};
  return raw as AutomationRuleConfig;
}

function resolveSteps(
  action: AutomationAction,
  config?: AutomationRuleConfig,
): AutomationStep[] {
  const steps = normalizeAutomationSteps(action, config);
  if (!firstAutomationAction(steps)) {
    throw new BadRequestException('حداقل یک عمل لازم است');
  }
  if (steps.length > MAX_AUTOMATION_STEPS) {
    throw new BadRequestException(
      `حداکثر ${MAX_AUTOMATION_STEPS} عمل در یک قانون مجاز است`,
    );
  }
  return steps;
}

function matchCondition(step: AutomationStep, facts: AutomationFacts): boolean {
  const field: AutomationConditionField = step.conditionField ?? 'has_person';
  const op: AutomationConditionOp = step.conditionOp ?? 'is_set';

  if (field === 'deal_amount') {
    const amount = facts.amount;
    const value = Number(step.conditionValue);
    if (amount == null || !Number.isFinite(value)) return false;
    if (op === 'gte') return amount >= value;
    if (op === 'lte') return amount <= value;
    if (op === 'eq') return amount === value;
    if (op === 'neq') return amount !== value;
    return false;
  }

  if (field === 'has_person') {
    return op === 'is_empty' ? !facts.hasPerson : facts.hasPerson;
  }

  if (field === 'has_company') {
    return op === 'is_empty' ? !facts.hasCompany : facts.hasCompany;
  }

  if (field === 'ticket_priority') {
    const current = facts.ticketPriority;
    const value = String(step.conditionValue ?? '');
    if (op === 'neq') return current !== value;
    return current === value;
  }

  return false;
}

function defaultTitle(action: AutomationAction, entityTitle: string) {
  if (action === 'create_activity') return `پیگیری خودکار: ${entityTitle}`;
  if (action === 'create_notification') return `اتوماسیون: ${entityTitle}`;
  return entityTitle;
}