hp-prod-tracker/src/lib/services/assignment-service.ts

import { prisma } from "@/lib/prisma";
import type { AssignmentRole } from "@/generated/prisma/client";
import { emitAssignmentCreated } from "@/lib/automation/event-bus";

// Register automation handler (side-effect import)
import "@/lib/services/automation-service";

export async function assignUserToStage(
  deliverableStageId: string,
  userId: string,
  role: AssignmentRole = "LEAD",
  options: { dryRun?: boolean } = {}
) {
  // Validate stage and user exist
  const [stage, user] = await Promise.all([
    prisma.deliverableStage.findUnique({
      where: { id: deliverableStageId },
      include: {
        template: true,
        deliverable: {
          select: {
            id: true,
            name: true,
            project: { select: { id: true, name: true, organizationId: true } },
          },
        },
      },
    }),
    prisma.user.findUnique({
      where: { id: userId },
      select: { id: true, name: true, email: true, maxCapacity: true },
    }),
  ]);

  if (!stage) throw new Error("Stage not found");
  if (!user) throw new Error("User not found");

  // Check for existing assignment
  const existing = await prisma.stageAssignment.findUnique({
    where: { deliverableStageId_userId: { deliverableStageId, userId } },
  });

  if (options.dryRun) {
    return {
      dryRun: true,
      action: existing ? "update_role" : "create_assignment",
      stageName: stage.template.name,
      userName: user.name || user.email,
      role,
    };
  }

  const result = await prisma.stageAssignment.upsert({
    where: {
      deliverableStageId_userId: { deliverableStageId, userId },
    },
    update: { role },
    create: { deliverableStageId, userId, role },
    include: { user: true, deliverableStage: { include: { template: true } } },
  });

  // Emit automation event (non-blocking)
  emitAssignmentCreated(stage!.deliverable.project.organizationId, {
    assignmentId: result.id,
    stageId: deliverableStageId,
    stageName: stage!.template.name,
    userId,
    userName: user!.name || user!.email,
    deliverableId: stage!.deliverable.id,
    projectId: stage!.deliverable.project.id,
  }).catch((err) => {
    console.error("[Automation] Failed to emit assignment.created:", err);
  });

  return result;
}

export async function removeAssignment(
  deliverableStageId: string,
  userId: string
) {
  return prisma.stageAssignment.delete({
    where: {
      deliverableStageId_userId: { deliverableStageId, userId },
    },
  });
}

export async function getMyWork(userId: string) {
  return prisma.stageAssignment.findMany({
    where: { userId },
    include: {
      deliverableStage: {
        include: {
          template: true,
          deliverable: {
            include: {
              project: { select: { id: true, name: true, projectCode: true } },
            },
          },
        },
      },
    },
    orderBy: { createdAt: "desc" },
  });
}

// ─── Bulk Operations ────────────────────────────────────

export interface BulkAssignItem {
  deliverableStageId: string;
  userId: string;
  role?: AssignmentRole;
}

export interface BulkAssignResult {
  total: number;
  succeeded: {
    deliverableStageId: string;
    stageName: string;
    userId: string;
    userName: string;
  }[];
  failed: {
    deliverableStageId: string;
    userId: string;
    reason: string;
  }[];
}

/**
 * Assign multiple artists to stages in a single transaction.
 * When dryRun is true, validates and returns preview without executing.
 */
export async function bulkAssignArtists(
  items: BulkAssignItem[],
  options: { dryRun?: boolean } = {}
): Promise<BulkAssignResult> {
  if (items.length === 0) {
    return { total: 0, succeeded: [], failed: [] };
  }

  // Fetch all referenced stages and users in bulk
  const stageIds = [...new Set(items.map((i) => i.deliverableStageId))];
  const userIds = [...new Set(items.map((i) => i.userId))];

  const [stages, users] = await Promise.all([
    prisma.deliverableStage.findMany({
      where: { id: { in: stageIds } },
      include: {
        template: true,
        deliverable: {
          select: {
            id: true,
            name: true,
            project: { select: { id: true, name: true, organizationId: true } },
          },
        },
      },
    }),
    prisma.user.findMany({
      where: { id: { in: userIds } },
      select: { id: true, name: true, email: true },
    }),
  ]);

  const stageMap = new Map(stages.map((s) => [s.id, s]));
  const userMap = new Map(users.map((u) => [u.id, u]));

  const succeeded: BulkAssignResult["succeeded"] = [];
  const failed: BulkAssignResult["failed"] = [];

  for (const item of items) {
    const stage = stageMap.get(item.deliverableStageId);
    if (!stage) {
      failed.push({
        deliverableStageId: item.deliverableStageId,
        userId: item.userId,
        reason: "Stage not found",
      });
      continue;
    }

    const user = userMap.get(item.userId);
    if (!user) {
      failed.push({
        deliverableStageId: item.deliverableStageId,
        userId: item.userId,
        reason: "User not found",
      });
      continue;
    }

    succeeded.push({
      deliverableStageId: item.deliverableStageId,
      stageName: stage.template.name,
      userId: item.userId,
      userName: user.name || user.email,
    });
  }

  if (options.dryRun) {
    return { total: items.length, succeeded, failed };
  }

  // Execute all valid assignments in a transaction
  if (succeeded.length > 0) {
    await prisma.$transaction(async (tx) => {
      for (const item of items) {
        if (!stageMap.has(item.deliverableStageId) || !userMap.has(item.userId))
          continue;
        await tx.stageAssignment.upsert({
          where: {
            deliverableStageId_userId: {
              deliverableStageId: item.deliverableStageId,
              userId: item.userId,
            },
          },
          update: { role: item.role || "LEAD" },
          create: {
            deliverableStageId: item.deliverableStageId,
            userId: item.userId,
            role: item.role || "LEAD",
          },
        });
      }
    });
  }

  // Emit automation events AFTER transaction commits
  if (succeeded.length > 0 && !options.dryRun) {
    for (const item of succeeded) {
      const stage = stageMap.get(item.deliverableStageId);
      if (!stage) continue;
      emitAssignmentCreated(stage.deliverable.project.organizationId, {
        assignmentId: `${item.deliverableStageId}:${item.userId}`,
        stageId: item.deliverableStageId,
        stageName: item.stageName,
        userId: item.userId,
        userName: item.userName,
        deliverableId: stage.deliverable.id,
        projectId: stage.deliverable.project.id,
      }).catch((err) => {
        console.error("[Automation] Failed to emit assignment.created (bulk):", err);
      });
    }
  }

  return { total: items.length, succeeded, failed };
}