import { type NextRequest } from "next/server";
import { prisma } from "@/lib/prisma";
import { ok, errorResponse, requireRole, parseJson, ApiError } from "@/lib/api";
import { CloseOperationSchema } from "@/lib/schemas";
import { audit } from "@/lib/audit";
import { clientIp } from "@/lib/request";

/**
 * Complete an operation. Only the current claim holder may close, and if
 * the operation is flagged qcRequired the payload must include an inline
 * QC block (pass/fail + optional measurements). Close does four things
 * atomically:
 *
 *   1. marks the operation completed + records completedAt,
 *   2. closes the open TimeLog with unitsProcessed / note if provided,
 *   3. writes a QCRecord if this op requires QC (or if the operator passed
 *      one in voluntarily),
 *   4. audits the close for later reporting.
 */
export async function POST(req: NextRequest, ctx: { params: Promise<{ id: string }> }) {
  try {
    const actor = await requireRole("operator");
    const { id } = await ctx.params;
    const body = await parseJson(req, CloseOperationSchema);

    const existing = await prisma.operation.findUnique({
      where: { id },
      select: {
        id: true,
        status: true,
        kind: true,
        claimedByUserId: true,
        qcRequired: true,
        unitsCompleted: true,
        part: {
          select: {
            qty: true,
            assembly: { select: { qty: true } },
          },
        },
      },
    });
    if (!existing) throw new ApiError(404, "not_found", "Operation not found");
    if (existing.claimedByUserId !== actor.id) {
      throw new ApiError(409, "not_claim_holder", "Only the current operator can complete this step");
    }
    if (existing.status !== "in_progress") {
      throw new ApiError(409, "op_not_active", "Step is not active");
    }
    // Dedicated QC ops (kind="qc") are all-about-QC — always demand the inline
    // payload. Regular work ops only demand it when the template/op was flagged
    // qcRequired. Either way, without a QC block we short-circuit.
    const qcMandatory = existing.kind === "qc" || existing.qcRequired;
    if (qcMandatory && !body.qc) {
      throw new ApiError(
        400,
        "qc_required",
        existing.kind === "qc"
          ? "QC result is required to complete an inspection step"
          : "This step requires an inline QC check before completing",
      );
    }

    // --- Partial vs fully-done detection --------------------------------
    // The operator hits "Done" but may have only produced some of the
    // assembly.qty × part.qty total units (e.g. end-of-shift handoff). In
    // that case the step should end up `partial` so the NEXT operator can
    // resume it — NOT `completed`, which locks it and requires admin to
    // reset. We infer the operator's intent from the units they typed in:
    //
    //   units == 0 (blank)  → "trust me, it's done" → completed
    //   units >= remaining  → math agrees → completed
    //   units <  remaining  → partial (clear claim, no completedAt)
    //
    // QC-required ops still demand a QC record even on partial close —
    // that's about material checks, not about finishing the batch.
    // QC ops don't track units at all; treat them as "done" by default.
    const units = body.unitsProcessed ?? 0;
    const totalUnits = existing.part.assembly.qty * existing.part.qty;
    const remaining = Math.max(0, totalUnits - existing.unitsCompleted);
    const isQcOp = existing.kind === "qc";
    const wouldFinish = isQcOp || units === 0 || units >= remaining;

    // QC failure short-circuits the usual partial-vs-complete decision: the
    // step moves to `qc_failed` which blocks further work until an admin
    // clears it via /api/v1/operations/:id/qc-reset. We still log the QC
    // record + close the timelog so the failure is on the paper trail.
    const qcFailed = body.qc !== undefined && body.qc.passed === false;
    const nextStatus: "completed" | "partial" | "qc_failed" = qcFailed
      ? "qc_failed"
      : wouldFinish
        ? "completed"
        : "partial";

    const now = new Date();
    await prisma.$transaction(async (tx) => {
      const openLog = await tx.timeLog.findFirst({
        where: { operationId: id, operatorId: actor.id, endedAt: null },
        orderBy: { startedAt: "desc" },
      });
      if (openLog) {
        await tx.timeLog.update({
          where: { id: openLog.id },
          data: {
            endedAt: now,
            unitsProcessed: body.unitsProcessed ?? null,
            note: body.note ?? null,
          },
        });
      }
      if (body.qc) {
        await tx.qCRecord.create({
          data: {
            operationId: id,
            operatorId: actor.id,
            kind: "inline",
            passed: body.qc.passed,
            measurements: body.qc.measurements ?? null,
            notes: body.qc.notes ?? null,
          },
        });
      }
      // unitsCompleted is cumulative across pause/resume cycles; on close we
      // add this session's batch so the total reflects everything the step
      // actually produced. Partial + qc_failed close release the claim so the
      // next operator (or admin, in the fail case) can act; completed close
      // sets completedAt for reporting.
      await tx.operation.update({
        where: { id },
        data: {
          status: nextStatus,
          completedAt: nextStatus === "completed" ? now : null,
          claimedByUserId: null,
          claimedAt: null,
          ...(units > 0 ? { unitsCompleted: { increment: units } } : {}),
        },
      });
    });

    const op = await prisma.operation.findUnique({ where: { id } });
    const action =
      nextStatus === "completed"
        ? "close_op"
        : nextStatus === "qc_failed"
          ? "qc_fail_op"
          : "partial_close_op";
    await audit({
      actorId: actor.id,
      action,
      entity: "Operation",
      entityId: id,
      after: {
        status: nextStatus,
        unitsProcessed: body.unitsProcessed ?? null,
        unitsRemaining: Math.max(0, remaining - units),
        qcPassed: body.qc?.passed ?? null,
      },
      ipAddress: clientIp(req),
    });

    return ok({
      operation: op,
      partial: nextStatus === "partial",
      qcFailed: nextStatus === "qc_failed",
    });
  } catch (err) {
    return errorResponse(err);
  }
}