import { randomUUID } from "node:crypto";
import type { Report } from "@prisma/client";
import { z } from "zod";
import { FIELD_EDITABLE, type WorkOrderStatus } from "@/lib/work-orders/status";
import { dateKeyToDbDate, localDateKey } from "@/lib/reports/dates";
import { assertCan, ServiceError, type ServiceCtx } from "@/server/services/context";
import { nextNumber } from "@/server/services/numbering";
import { requireVisibleWorkOrder } from "@/server/services/work-orders/visibility";
// TODO(merge L2): import from "@/server/services/work-orders/transition" and ".../guards"
import { getCompletionBlockers } from "@/server/services/work-orders/completion";
import { transitionWorkOrder } from "@/server/services/work-orders/transition";
import { buildReportContent, tenantTimeZone } from "./build-content";
import { auditReport, reportAuditView } from "./common";

export const createReportSchema = z.object({
  workOrderId: z.string().min(1).max(64),
  reportDate: z
    .string()
    .regex(/^\d{4}-\d{2}-\d{2}$/)
    .optional(),
  clientId: z.string().min(1).max(64).optional(),
});
export type CreateReportInput = z.input<typeof createReportSchema>;
export type CreateReportResult = { report: Report; created: boolean };

async function byClientId(ctx: ServiceCtx, clientId?: string): Promise<Report | null> {
  if (!clientId) return null;
  return ctx.db.report.findFirst({ where: { clientId } });
}

async function createDraft(
  ctx: ServiceCtx,
  args: { workOrderId: string; type: "daily" | "completion"; dateKey: string; clientId?: string },
): Promise<Report> {
  const reportNumber = await nextNumber(ctx.db, ctx.tenantId, "report");
  const content = await buildReportContent(ctx, {
    workOrderId: args.workOrderId,
    type: args.type,
    reportDate: args.dateKey,
    reportNumber,
    version: 1,
    technicianUserId: ctx.userId,
  });
  const report = await ctx.db.report.create({
    data: {
      tenantId: ctx.tenantId,
      workOrderId: args.workOrderId,
      type: args.type,
      reportDate: dateKeyToDbDate(args.dateKey),
      version: 1,
      lineageId: randomUUID(),
      status: "draft",
      content,
      createdById: ctx.userId,
      clientId: args.clientId ?? null,
    },
  });
  await auditReport(ctx, "create", report.id, null, { ...reportAuditView(report), reportNumber });
  return report;
}

/**
 * Tagesbericht (Spec §16.3): draft for one calendar day, work order → daily_report_created, order stays open.
 * Idempotent per (work order, day): an existing draft/rejected report of that day is returned.
 */
export async function createDailyReport(ctx: ServiceCtx, raw: CreateReportInput): Promise<CreateReportResult> {
  assertCan(ctx, "report:write");
  const input = createReportSchema.parse(raw);
  const dup = await byClientId(ctx, input.clientId);
  if (dup) return { report: dup, created: false };

  const wo = await requireVisibleWorkOrder(ctx, input.workOrderId, { id: true, status: true });
  const dateKey = input.reportDate ?? localDateKey(new Date(), await tenantTimeZone(ctx));

  const existing = await ctx.db.report.findFirst({
    where: { workOrderId: wo.id, type: "daily", reportDate: dateKeyToDbDate(dateKey), status: { not: "superseded" } },
    orderBy: { version: "desc" },
  });
  if (existing) {
    if (existing.status === "draft" || existing.status === "rejected") return { report: existing, created: false };
    throw new ServiceError("conflict", "daily report for this day already submitted");
  }

  const status = wo.status as WorkOrderStatus;
  // one daily report per order and day → stable occurrence id for L6 mail deduplication
  const eventData = { occurrenceId: `${wo.id}:${dateKey}` };
  if (status === "paused" || status === "waiting_material") {
    await transitionWorkOrder(ctx, { workOrderId: wo.id, to: "in_progress" });
    await transitionWorkOrder(ctx, { workOrderId: wo.id, to: "daily_report_created", eventData });
  } else if (status === "in_progress") {
    await transitionWorkOrder(ctx, { workOrderId: wo.id, to: "daily_report_created", eventData });
  } else if (status !== "daily_report_created") {
    throw new ServiceError("invalid", `work order is ${status}`);
  }

  const report = await createDraft(ctx, { workOrderId: wo.id, type: "daily", dateKey, clientId: input.clientId });
  return { report, created: true };
}

/**
 * Abschlussbericht (Spec §17): checks completion guards first (blocked → CompletionBlocker[] in details).
 * One completion lineage per work order; changes after approval go through createNewVersion.
 */
export async function createCompletionReport(ctx: ServiceCtx, raw: CreateReportInput): Promise<CreateReportResult> {
  assertCan(ctx, "report:write");
  const input = createReportSchema.parse(raw);
  const dup = await byClientId(ctx, input.clientId);
  if (dup) return { report: dup, created: false };

  const wo = await requireVisibleWorkOrder(ctx, input.workOrderId, { id: true, status: true });
  const existing = await ctx.db.report.findFirst({
    where: { workOrderId: wo.id, type: "completion", status: { not: "superseded" } },
    orderBy: { version: "desc" },
  });
  if (existing) {
    if (existing.status === "draft" || existing.status === "rejected") return { report: existing, created: false };
    throw new ServiceError("conflict", `completion report is ${existing.status}`);
  }
  if (!FIELD_EDITABLE.includes(wo.status as WorkOrderStatus)) throw new ServiceError("invalid", `work order is ${wo.status}`);

  const blockers = await getCompletionBlockers(ctx, wo.id);
  if (blockers.length) throw new ServiceError("blocked", "completion blocked", blockers);

  const dateKey = input.reportDate ?? localDateKey(new Date(), await tenantTimeZone(ctx));
  const report = await createDraft(ctx, { workOrderId: wo.id, type: "completion", dateKey, clientId: input.clientId });
  return { report, created: true };
}