import Link from "next/link";
import { notFound } from "next/navigation";
import { getTranslations } from "next-intl/server";
import { ArrowLeft, Pencil, Siren, UsersRound } from "lucide-react";
import { Modal } from "@/components/modal";
import { PlanningSuggestions } from "@/components/planning/suggestions-section";
import { SCHEDULABLE_STATUSES } from "@/lib/planning/capacity";
import { ActionForm } from "@/components/work-orders/action-form";
import { buttonCls } from "@/components/work-orders/button-cls";
import {
  ChecklistTab,
  DocumentsTab,
  HistoryTab,
  MaterialTab,
  NotesTab,
  OverviewTab,
  PhotosTab,
  ReportsTab,
  TimesTab,
} from "@/components/work-orders/detail-tabs";
import { WorkOrderBillingTab } from "@/components/billing/work-order-billing-tab";
import { pageContext } from "@/components/work-orders/page-context";
import { Field, inputCls, LinkTabs, StatusBadge } from "@/components/work-orders/ui";
import { WorkOrderFields } from "@/components/work-orders/work-order-fields";
import { WORK_ORDER_STATUSES, type WorkOrderStatus } from "@/lib/work-orders/status";
import { assignAction, transitionAction, updateWorkOrderAction } from "@/server/actions/work_orders/work-orders";
import { ServiceError } from "@/server/services/context";
import { FINAL_STATUSES, PLANNING_LOCKED } from "@/server/services/work-orders/_shared";
import { availableTransitions, getWorkOrderDetail } from "@/server/services/work-orders/detail";
import { customerDisplayName, customerOption, teamOptions, userOptions } from "@/server/services/work-orders/options";
import { listOrderTypes } from "@/server/services/work-orders/settings";
import { billingModuleActive, reasonRequired } from "@/server/services/work-orders/transition";

const TABS = ["overview", "checklist", "material", "times", "photos", "notes", "reports", "billing", "documents", "history"] as const; // L14: billing
type Tab = (typeof TABS)[number];
type SP = Record<string, string | string[] | undefined>;
const one = (v: string | string[] | undefined) => (Array.isArray(v) ? v[0] : v);
const idx = (s: WorkOrderStatus) => WORK_ORDER_STATUSES.indexOf(s);

/** Backoffice work order detail: header with status + next primary action, tabs, popups (assign/edit/reason). */
export default async function WorkOrderDetailPage({ params, searchParams }: { params: Promise<{ id: string }>; searchParams: Promise<SP> }) {
  const { id } = await params;
  const sp = await searchParams;
  const { ctx, locale, tz, can } = await pageContext();
  const t = await getTranslations("workOrders");
  const tc = await getTranslations("common");

  let wo;
  try {
    wo = await getWorkOrderDetail(ctx, id);
  } catch (err) {
    if (err instanceof ServiceError && err.code === "not_found") notFound();
    throw err;
  }

  const tabParam = one(sp.tab);
  const tab: Tab = (TABS as readonly string[]).includes(tabParam ?? "") ? (tabParam as Tab) : "overview";
  const selfHref = `/work-orders/${wo.id}${tab === "overview" ? "" : `?tab=${tab}`}`;
  const withParam = (k: string, v: string) => `/work-orders/${wo.id}?${tab === "overview" ? "" : `tab=${tab}&`}${k}=${v}`;

  const transitions = availableTransitions(ctx, wo.status);
  const canAssign = can("work_order:assign") && !PLANNING_LOCKED.includes(wo.status);
  const canWrite = can("work_order:write") && !FINAL_STATUSES.includes(wo.status);
  const canEditPlanning = can("work_order:write") && !PLANNING_LOCKED.includes(wo.status);
  const assignFirst = canAssign && ["draft", "review_required", "planned"].includes(wo.status);

  // Primary = furthest forward step (never cancel/backward); assignment goes through the popup.
  const forward = transitions.filter((to) => to !== "cancelled" && idx(to) > idx(wo.status) && !(assignFirst && to === "assigned"));
  const primary = assignFirst ? null : forward.sort((a, b) => idx(b) - idx(a))[0] ?? null;
  const secondary = transitions.filter((to) => to !== primary && to !== "cancelled" && !(assignFirst && to === "assigned"));

  const label = (to: WorkOrderStatus) =>
    wo.status === "in_review" && to === "in_progress"
      ? t("transition.correction")
      : wo.status === "released_for_billing" && to === "in_review"
        ? t("transition.revoke")
        : t(`transition.to.${to}`);

  const transitionButton = (to: WorkOrderStatus, variant: "primary" | "outline" | "danger") =>
    reasonRequired(wo.status, to) ? (
      <Link key={to} href={withParam("transition", to)} scroll={false} className={buttonCls(variant)}>
        {label(to)}
      </Link>
    ) : (
      <ActionForm key={to} action={transitionAction} submitLabel={label(to)} pendingLabel={t("transition.pending")} variant={variant} footerClassName="mt-0">
        <input type="hidden" name="workOrderId" value={wo.id} />
        <input type="hidden" name="to" value={to} />
        <input type="hidden" name="baseVersion" value={wo.version} />
        <input type="hidden" name="returnTab" value={tab} />
      </ActionForm>
    );

  // Popups
  const reasonTo = one(sp.transition) as WorkOrderStatus | undefined;
  const showReason = reasonTo && transitions.includes(reasonTo) && reasonRequired(wo.status, reasonTo);
  const showAssign = canAssign && one(sp.assign) === "1";
  const showEdit = canWrite && one(sp.edit) === "1";
  const [teams, users, editData, orderTypes] = await Promise.all([
    showAssign ? teamOptions(ctx) : Promise.resolve([]),
    showAssign ? userOptions(ctx) : Promise.resolve([]),
    showEdit ? customerOption(ctx, wo.customerId) : Promise.resolve(null),
    showEdit ? listOrderTypes(ctx) : Promise.resolve([]),
  ]);

  // L14: with the billing overview active, "billed" is set only there (snapshot + position assignment) → no direct button
  const billingOverviewActive = await billingModuleActive(ctx); // L17: incl. package tier
  const billingTransitions = transitions.filter(
    (to) =>
      (to === "released_for_billing" || (to === "billed" && !billingOverviewActive)) ||
      (wo.status === "in_review" && to === "in_progress") ||
      (wo.status === "released_for_billing" && to === "in_review"),
  );

  const tabProps = { ctx, wo, locale, tz, canEdit: canEditPlanning };

  return (
    <main className="flex-1 p-4 md:p-6">
      <Link href="/work-orders" className="inline-flex min-h-11 items-center gap-1.5 text-[13px] font-semibold text-muted-foreground hover:text-foreground">
        <ArrowLeft className="size-4" aria-hidden />
        {t("detail.back")}
      </Link>

      <header className="shadow-card mt-1 rounded-xl border border-l-4 bg-card p-4 md:p-5" style={{ borderLeftColor: "var(--ui-primary)" }}>
        <div className="flex flex-wrap items-start justify-between gap-4">
          <div className="min-w-0">
            <p className="flex flex-wrap items-center gap-2 text-xs text-muted-foreground">
              <span className="font-mono">{wo.number}</span>
              <span>· {t("detail.version", { version: wo.version })}</span>
              {wo.isEmergency && (
                <span className="inline-flex items-center gap-1 font-semibold text-[var(--risk)]">
                  <Siren className="size-3.5" aria-hidden />
                  {t("emergency")}
                </span>
              )}
            </p>
            <h1 className="mt-1 text-[22px] break-words">{wo.title}</h1>
            <p className="mt-1 text-sm">
              {customerDisplayName(wo.customer)}
              {wo.site && <span className="text-muted-foreground"> · {wo.site.name}</span>}
            </p>
            <div className="mt-2 flex flex-wrap items-center gap-3">
              <StatusBadge status={wo.status} label={t(`status.${wo.status}`)} className="text-sm" />
              <span className="inline-flex items-center gap-1 text-xs text-muted-foreground">
                <UsersRound className="size-3.5" aria-hidden />
                {wo.team?.name ?? t("unassigned")}
              </span>
            </div>
          </div>
          <div className="flex flex-col items-stretch gap-2 sm:items-end">
            <span className="text-xs font-semibold text-muted-foreground">{t("detail.nextStep")}</span>
            <div className="flex flex-wrap gap-2 sm:justify-end">
              {assignFirst && (
                <Link href={withParam("assign", "1")} scroll={false} className={buttonCls("primary")}>
                  {t("detail.assign")}
                </Link>
              )}
              {primary && transitionButton(primary, "primary")}
              {!assignFirst && !primary && <span className="text-sm text-muted-foreground">{t("detail.noActions")}</span>}
            </div>
          </div>
        </div>

        <div className="mt-4 flex flex-wrap items-center gap-2 border-t pt-3">
          {secondary.map((to) => transitionButton(to, "outline"))}
          {canAssign && !assignFirst && (
            <Link href={withParam("assign", "1")} scroll={false} className={buttonCls("outline")}>
              <UsersRound className="size-4" aria-hidden />
              {t("detail.reassign")}
            </Link>
          )}
          {canWrite && (
            <Link href={withParam("edit", "1")} scroll={false} className={buttonCls("outline")}>
              <Pencil className="size-4" aria-hidden />
              {t("detail.edit")}
            </Link>
          )}
          {transitions.includes("cancelled") && (
            <Link href={withParam("transition", "cancelled")} scroll={false} className={`${buttonCls("danger")} sm:ml-auto`}>
              {t("detail.cancel")}
            </Link>
          )}
        </div>
      </header>

      {tab === "overview" && canAssign && SCHEDULABLE_STATUSES.includes(wo.status) && <PlanningSuggestions ctx={ctx} workOrderId={wo.id} locale={locale} tz={tz} />}

      <div className="mt-4">
        <LinkTabs
          label={t("detail.tabs.overview")}
          items={TABS.filter((k) => k !== "billing" || billingOverviewActive).map((k) => ({ href: `/work-orders/${wo.id}${k === "overview" ? "" : `?tab=${k}`}`, label: t(`detail.tabs.${k}`), active: tab === k }))}
        />
      </div>

      <div className="mt-4">
        {tab === "overview" && <OverviewTab {...tabProps} />}
        {tab === "checklist" && <ChecklistTab {...tabProps} />}
        {tab === "material" && <MaterialTab {...tabProps} />}
        {tab === "times" && <TimesTab {...tabProps} />}
        {tab === "photos" && <PhotosTab {...tabProps} />}
        {tab === "notes" && <NotesTab {...tabProps} />}
        {tab === "reports" && (
          <ReportsTab
            {...tabProps}
            billing={
              billingTransitions.length > 0 ? (
                <div className="flex flex-wrap gap-2">
                  {billingTransitions.map((to) => transitionButton(to, to === "released_for_billing" || to === "billed" ? "primary" : "outline"))}
                </div>
              ) : undefined
            }
          />
        )}
        {tab === "billing" && billingOverviewActive && <WorkOrderBillingTab ctx={ctx} wo={wo} locale={locale} tz={tz} />}
        {tab === "documents" && <DocumentsTab {...tabProps} uploadError={one(sp.uploadError)} uploaded={one(sp.uploaded) === "1"} />}
        {tab === "history" && <HistoryTab {...tabProps} />}
      </div>

      {showReason && reasonTo && (
        <Modal title={label(reasonTo)} sub={t("transition.reasonTitle")} closeHref={selfHref} closeLabel={tc("close")}>
          <ActionForm action={transitionAction} submitLabel={t("transition.confirm")} pendingLabel={t("transition.pending")} variant={reasonTo === "cancelled" ? "danger" : "default"} className="p-5">
            <input type="hidden" name="workOrderId" value={wo.id} />
            <input type="hidden" name="to" value={reasonTo} />
            <input type="hidden" name="baseVersion" value={wo.version} />
            <input type="hidden" name="returnTab" value={tab} />
            <Field label={`${t("transition.reason")} *`} htmlFor="tr-reason">
              <textarea id="tr-reason" name="reason" required rows={4} maxLength={2000} placeholder={t("transition.reasonPlaceholder")} className={`${inputCls} py-2`} autoFocus />
            </Field>
          </ActionForm>
        </Modal>
      )}

      {showAssign && (
        <Modal title={t("assign.title")} sub={t("assign.sub")} closeHref={selfHref} closeLabel={tc("close")}>
          {teams.length === 0 ? (
            <p className="p-5 text-sm text-muted-foreground">{t("assign.noTeams")}</p>
          ) : (
            <ActionForm action={assignAction} submitLabel={t("assign.submit")} pendingLabel={t("assign.pending")} variant="primary" className="grid gap-4 p-5 md:grid-cols-2">
              <input type="hidden" name="workOrderId" value={wo.id} />
              <input type="hidden" name="baseVersion" value={wo.version} />
              <Field label={`${t("assign.team")} *`} htmlFor="as-team">
                <select id="as-team" name="teamId" required defaultValue={wo.team?.id ?? ""} className={inputCls}>
                  <option value="">{t("assign.chooseTeam")}</option>
                  {teams.map((tm) => (
                    <option key={tm.id} value={tm.id}>
                      {tm.name}
                    </option>
                  ))}
                </select>
              </Field>
              <Field label={t("assign.teamLead")} htmlFor="as-lead">
                <select id="as-lead" name="teamLeadUserId" defaultValue={wo.teamLead?.id ?? ""} className={inputCls}>
                  <option value="">{t("assign.teamLeadDefault")}</option>
                  {users.map((u) => (
                    <option key={u.id} value={u.id}>
                      {u.name}
                    </option>
                  ))}
                </select>
              </Field>
              <fieldset className="md:col-span-2">
                <legend className="mb-1 text-[13px] font-semibold">{t("assign.members")}</legend>
                <div className="grid gap-x-4 sm:grid-cols-2 lg:grid-cols-3">
                  {users.map((u) => (
                    <label key={u.id} className="flex min-h-11 items-center gap-2.5 text-sm">
                      <input type="checkbox" name="userIds" value={u.id} defaultChecked={wo.assignees.some((a) => a.user.id === u.id)} className="size-5 accent-[var(--ui-primary)]" />
                      {u.name}
                      <span className="text-xs text-muted-foreground">{teams.filter((tm) => tm.members.some((m) => m.user.id === u.id)).map((tm) => tm.name).join(", ")}</span>
                    </label>
                  ))}
                </div>
              </fieldset>
            </ActionForm>
          )}
        </Modal>
      )}

      {showEdit && editData && (
        <Modal title={t("edit.title")} sub={`${wo.number} · ${customerDisplayName(wo.customer)}`} closeHref={selfHref} closeLabel={tc("close")}>
          <ActionForm action={updateWorkOrderAction.bind(null, wo.id)} submitLabel={t("edit.submit")} pendingLabel={t("edit.pending")} className="p-5">
            <input type="hidden" name="baseVersion" value={wo.version} />
            <WorkOrderFields
              mode="edit"
              tz={tz}
              sites={editData.sites.map((s) => ({ id: s.id, name: [s.name, s.city].filter(Boolean).join(" · ") }))}
              contacts={editData.contacts.map((c) => ({ id: c.id, name: c.name }))}
              orderTypes={orderTypes.map((o) => ({ id: o.id, name: o.active ? o.name : `${o.name} (–)` }))}
              defaults={{
                title: wo.title,
                siteId: wo.siteId,
                contactId: wo.contactId,
                orderTypeId: wo.orderTypeId,
                priority: wo.priority,
                plannedStart: wo.plannedStart,
                plannedEnd: wo.plannedEnd,
                description: wo.description,
                scope: wo.scope,
                internalNotes: wo.internalNotes,
                technicianNotes: wo.technicianNotes,
                signatureRequired: wo.signatureRequired,
                billingType: wo.billingType,
                externalOrderNumber: wo.externalOrderNumber,
                offerNumber: wo.offerNumber,
              }}
            />
          </ActionForm>
        </Modal>
      )}
    </main>
  );
}