import { ArrowLeft, Pencil, Save, Trash2 } from "lucide-react";
import { FormEvent, useEffect, useMemo, useState } from "react";
import { toast } from "sonner";
import { Alert } from "@/components/ui/alert";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from "@/components/ui/dialog";
import { Input } from "@/components/ui/input";
import { Textarea } from "@/components/ui/textarea";
import { CopyTicketButton } from "@/components/CopyTicketButton";
import { HelpLink } from "@/components/HelpLink";
import { OrganizationSelect } from "@/components/OrganizationSelect";
import {
  createSession,
  deleteSession,
  getTicketDetails,
  getTicketPeriod,
  updateSessionBilling,
  updateSessionDetails,
  updateTicket,
  updateTicketDayBilling
} from "../api";
import { currentDay, currentMonth, formatDate, formatDateTime, formatMinutes, formatTimeRange } from "../format";
import type { BillingStatus, PeriodType, SessionEntry, TicketDetailPeriodType, TicketPeriod, WorkType } from "../types";
import { cn } from "@/lib/utils";

type TicketDetailPageProps = {
  periodType: TicketDetailPeriodType;
  period: string;
  ticketId: string;
  onNavigate: (to: string) => void;
  onOpenTicketChange?: (ticket: {
    key: string;
    ticketId: string;
    ticketNumber: string;
    periodType: TicketDetailPeriodType;
    period: string;
    path: string;
    dirty: boolean;
  }) => void;
};

type TicketSessionFormState = {
  organizationId: string;
  organizationName: string | null;
  activity: string;
  workType: WorkType;
  day: string;
  startTime: string;
  endTime: string;
};

function emptyTicketSessionForm(): TicketSessionFormState {
  return {
    organizationId: "",
    organizationName: null,
    activity: "",
    workType: "support",
    day: currentDay(),
    startTime: "09:00",
    endTime: "09:30"
  };
}

function BillingButtons({
  session,
  disabled,
  loading,
  onChange
}: {
  session: SessionEntry;
  disabled: boolean;
  loading: boolean;
  onChange: (status: BillingStatus) => void;
}) {
  const status = session.billing_status;

  return (
    <div className="grid grid-cols-2 gap-1.5 sm:inline-grid">
      <Button
        type="button"
        size="sm"
        variant={status === "billed" ? "default" : "secondary"}
        disabled={loading || (disabled && status !== "billed")}
        onClick={() => onChange(status === "billed" ? null : "billed")}
        className={cn("h-8", status === "billed" ? "" : "bg-secondary/70")}
      >
        Abgerechnet
      </Button>
      <Button
        type="button"
        size="sm"
        variant={status === "non_billable" ? "default" : "secondary"}
        disabled={loading || (disabled && status !== "non_billable")}
        onClick={() => onChange(status === "non_billable" ? null : "non_billable")}
        className={cn("h-8", status === "non_billable" ? "" : "bg-secondary/70")}
      >
        Nicht abrechenbar
      </Button>
    </div>
  );
}

function sessionDayKey(value: string) {
  const date = new Date(value);
  return `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, "0")}-${String(date.getDate()).padStart(2, "0")}`;
}

function toDateLocalValue(value: string) {
  const date = new Date(value);
  const offsetMs = date.getTimezoneOffset() * 60_000;
  return new Date(date.getTime() - offsetMs).toISOString().slice(0, 10);
}

function toTimeLocalValue(value: string) {
  const date = new Date(value);
  const offsetMs = date.getTimezoneOffset() * 60_000;
  return new Date(date.getTime() - offsetMs).toISOString().slice(11, 16);
}

function formatHoursInput(minutes?: number | null) {
  if (minutes === null || minutes === undefined) {
    return "";
  }

  return new Intl.NumberFormat("de-DE", { maximumFractionDigits: 2 }).format(minutes / 60);
}

function parseHoursInput(value: string) {
  const trimmed = value.trim();

  if (!trimmed) {
    return null;
  }

  if (/[,.]$/.test(trimmed)) {
    return undefined;
  }

  const hours = Number(trimmed.replace(",", "."));

  if (!Number.isFinite(hours) || hours < 0) {
    return undefined;
  }

  return Math.round(hours * 60);
}

function isPartialHoursInput(value: string) {
  return /^\d*(?:[,.]\d*)?$/.test(value.trim());
}

export function TicketDetailPage({ periodType, period, ticketId, onNavigate, onOpenTicketChange }: TicketDetailPageProps) {
  const initialGlobalMonthFilter = periodType === "all" && period !== "all" ? period : currentMonth();
  const [data, setData] = useState<TicketPeriod | null>(null);
  const [loadingId, setLoadingId] = useState<string | null>(null);
  const [deletingId, setDeletingId] = useState<string | null>(null);
  const [savingTicket, setSavingTicket] = useState(false);
  const [editTicketNumber, setEditTicketNumber] = useState("");
  const [editOrganizationId, setEditOrganizationId] = useState("");
  const [editOrganizationName, setEditOrganizationName] = useState<string | null>(null);
  const [editWorkType, setEditWorkType] = useState<WorkType>("support");
  const [editingSession, setEditingSession] = useState<SessionEntry | null>(null);
  const [editSessionOrganizationId, setEditSessionOrganizationId] = useState("");
  const [editSessionOrganizationName, setEditSessionOrganizationName] = useState<string | null>(null);
  const [editSessionActivity, setEditSessionActivity] = useState("");
  const [editSessionWorkType, setEditSessionWorkType] = useState<WorkType>("support");
  const [editSessionDay, setEditSessionDay] = useState("");
  const [editSessionStartTime, setEditSessionStartTime] = useState("");
  const [editSessionEndTime, setEditSessionEndTime] = useState("");
  const [savingSessionDetails, setSavingSessionDetails] = useState(false);
  const [dayBillingInputs, setDayBillingInputs] = useState<Record<string, string>>({});
  const [savingDayBillingKey, setSavingDayBillingKey] = useState<string | null>(null);
  const [ticketSession, setTicketSession] = useState<TicketSessionFormState>(() => emptyTicketSessionForm());
  const [savingTicketSession, setSavingTicketSession] = useState(false);
  const [globalMonthFilter, setGlobalMonthFilter] = useState(initialGlobalMonthFilter);
  const [globalStatusFilter, setGlobalStatusFilter] = useState<"all" | "open" | "billed" | "non_billable">("all");
  const [globalSourceFilter, setGlobalSourceFilter] = useState<"all" | "manual" | "recurring">("all");

  async function load() {
    try {
      setData(
        periodType === "all"
          ? await getTicketDetails(ticketId, {
              month: globalMonthFilter,
              status: globalStatusFilter,
              source: globalSourceFilter
            })
          : await getTicketPeriod(periodType, period, ticketId)
      );
    } catch (error) {
      toast.error("Ticket konnte nicht geladen werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    }
  }

  useEffect(() => {
    void load();
  }, [periodType, period, ticketId, globalMonthFilter, globalStatusFilter, globalSourceFilter]);

  useEffect(() => {
    if (periodType !== "all") {
      return;
    }

    setGlobalMonthFilter(period !== "all" ? period : currentMonth());
  }, [periodType, period, ticketId]);

  useEffect(() => {
    const nextInputs = Object.fromEntries((data?.dayBillings ?? []).map((billing) => [billing.day, formatHoursInput(billing.billed_minutes)]));
    setDayBillingInputs(nextInputs);
  }, [data?.dayBillings]);

  useEffect(() => {
    if (!data?.ticket) {
      return;
    }

    setEditTicketNumber(data.ticket.ticket_number);
    setEditOrganizationId(data.ticket.organization_id ?? "");
    setEditOrganizationName(data.ticket.organization_name ?? null);
    setEditWorkType(data.ticket.work_type ?? "support");
    setTicketSession((current) => ({
      ...current,
      organizationId: data.ticket.organization_id ?? current.organizationId,
      organizationName: data.ticket.organization_name ?? current.organizationName,
      workType: data.ticket.work_type ?? current.workType
    }));
  }, [data?.ticket]);

  const ticket = data?.ticket;
  const isGlobalTicket = periodType === "all";
  const isPeriodClosed = Boolean(data?.closed);
  const periodLabel = periodType === "month" ? "Monat" : periodType === "day" ? "Tag" : "Ticket";
  const sessionsScopeLabel = isGlobalTicket
    ? globalMonthFilter === "all"
      ? "im gesamten Ticketverlauf"
      : `im Monat ${globalMonthFilter}`
    : `im ${periodLabel.toLowerCase()} ${period}`;
  const teamspaceLabel = isGlobalTicket || periodType === "month" ? "Teamspace gesamt" : "Teamspace Tag";
  const availableMonths = data?.availableMonths ?? [];
  const selectedMonthHasSessions = availableMonths.some((month) => month.month === globalMonthFilter);
  const dayBillingMap = useMemo(() => new Map((data?.dayBillings ?? []).map((billing) => [billing.day, billing.billed_minutes])), [data?.dayBillings]);
  const savedDayBillingInput = (day: string) => formatHoursInput(dayBillingMap.get(day));
  const isDayBillingDirty = (day: string) => (dayBillingInputs[day] ?? "") !== savedDayBillingInput(day);
  const sessionGroups = useMemo(() => {
    const groups = new Map<
      string,
      { key: string; label: string; totalMinutes: number; nonBillableMinutes: number; openMinutes: number; sessions: SessionEntry[] }
    >();

    for (const session of data?.sessions ?? []) {
      const key = sessionDayKey(session.started_at);
      const group = groups.get(key);
      const billedMinutes = session.billing_status === "billed" ? session.rounded_minutes : 0;
      const nonBillableMinutes = session.billing_status === "non_billable" ? session.rounded_minutes : 0;
      const openMinutes = session.billing_status === null ? session.rounded_minutes : 0;

      if (group) {
        group.sessions.push(session);
        group.totalMinutes += billedMinutes;
        group.nonBillableMinutes += nonBillableMinutes;
        group.openMinutes += openMinutes;
        continue;
      }

      groups.set(key, {
        key,
        label: formatDate(session.started_at),
        totalMinutes: billedMinutes,
        nonBillableMinutes,
        openMinutes,
        sessions: [session]
      });
    }

    return Array.from(groups.values());
  }, [data?.sessions]);
  const periodTotalMinutes = sessionGroups.reduce((sum, group) => sum + group.totalMinutes, 0);
  const periodTeamspaceMinutes = Array.from(dayBillingMap.values()).reduce((sum, minutes) => sum + Number(minutes ?? 0), 0);
  const ticketDataDirty = Boolean(
    ticket &&
      (editTicketNumber !== ticket.ticket_number ||
        editOrganizationId !== (ticket.organization_id ?? "") ||
        editWorkType !== (ticket.work_type ?? "support"))
  );
  const hasUnsavedChanges = ticketDataDirty || sessionGroups.some((group) => isDayBillingDirty(group.key));

  useEffect(() => {
    if (!ticket) {
      return;
    }

    const ticketMonth = isGlobalTicket ? globalMonthFilter : periodType === "day" ? period.slice(0, 7) : period;

    onOpenTicketChange?.({
      key: `ticket:${ticket.id}`,
      ticketId: ticket.id,
      ticketNumber: ticket.ticket_number,
      periodType: "all",
      period: ticketMonth,
      path: `/tickets/${ticket.id}?month=${ticketMonth}`,
      dirty: hasUnsavedChanges
    });
  }, [ticket, periodType, period, isGlobalTicket, globalMonthFilter, hasUnsavedChanges, onOpenTicketChange]);

  async function setBilling(sessionId: string, billingStatus: BillingStatus) {
    if (isPeriodClosed && billingStatus !== null) {
      toast.warning("Monat ist abgeschlossen", {
        description: "Öffne den Monat zuerst wieder, um Bewertungen zu ändern."
      });
      return;
    }

    setLoadingId(sessionId);
    try {
      await updateSessionBilling(sessionId, billingStatus);
      await load();
    } catch (error) {
      toast.error("Status konnte nicht gespeichert werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setLoadingId(null);
    }
  }

  async function saveDayBilling(day: string) {
    if (!ticket) {
      return;
    }

    if (isPeriodClosed) {
      toast.warning("Monat ist abgeschlossen", {
        description: "Öffne den Monat zuerst wieder, um Teamspace-Zeiten zu ändern."
      });
      return;
    }

    const parsedMinutes = parseHoursInput(dayBillingInputs[day] ?? "");

    if (parsedMinutes === undefined) {
      toast.error("Teamspace-Zeit prüfen", {
        description: "Bitte Stunden als positive Zahl eintragen, z.B. 1,5."
      });
      return;
    }

    const currentMinutes = dayBillingMap.get(day) ?? null;

    if (parsedMinutes === currentMinutes) {
      return;
    }

    setSavingDayBillingKey(day);
    try {
      await updateTicketDayBilling(ticket.id, day, parsedMinutes);
      toast.success("Zeit gespeichert");
      await load();
    } catch (error) {
      toast.error("Zeit konnte nicht gespeichert werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setSavingDayBillingKey(null);
    }
  }

  async function saveTicketData(event: FormEvent) {
    event.preventDefault();

    if (!ticket) {
      return;
    }

    if (!editOrganizationId) {
      toast.error("Organisation wählen");
      return;
    }

    setSavingTicket(true);
    try {
      await updateTicket(ticket.id, {
        ticketNumber: editTicketNumber,
        organizationId: editOrganizationId,
        workType: editWorkType
      });
      toast.success("Ticketdaten gespeichert", {
        description: "Organisation und Art wurden auf die vorhandenen Sessions übernommen."
      });
      await load();
    } catch (error) {
      toast.error("Ticketdaten konnten nicht gespeichert werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setSavingTicket(false);
    }
  }

  async function submitTicketSession(event: FormEvent) {
    event.preventDefault();

    if (!ticket) {
      return;
    }

    const effectiveOrganizationId = ticket.organization_id ?? ticketSession.organizationId;
    const effectiveWorkType = ticket.work_type ?? ticketSession.workType;

    if (!effectiveOrganizationId) {
      toast.error("Organisation wählen");
      return;
    }

    const startedAt = new Date(`${ticketSession.day}T${ticketSession.startTime}:00`);
    const endedAt = new Date(`${ticketSession.day}T${ticketSession.endTime}:00`);

    if (Number.isNaN(startedAt.getTime()) || Number.isNaN(endedAt.getTime())) {
      toast.error("Datum oder Uhrzeit prüfen");
      return;
    }

    if (endedAt <= startedAt) {
      toast.error("Ende muss nach Beginn liegen");
      return;
    }

    const durationSeconds = Math.floor((endedAt.getTime() - startedAt.getTime()) / 1000);

    setSavingTicketSession(true);

    try {
      await createSession({
        ticketNumber: ticket.ticket_number,
        organizationId: effectiveOrganizationId,
        activity: ticketSession.activity,
        workType: effectiveWorkType,
        startedAt: startedAt.toISOString(),
        endedAt: endedAt.toISOString(),
        durationSeconds
      });
      toast.success("Session nachgetragen", {
        description: "Der Eintrag wurde diesem Ticket zugeordnet. Betroffene Abschlüsse wurden wieder geöffnet."
      });
      setTicketSession({
        ...emptyTicketSessionForm(),
        organizationId: ticket.organization_id ?? "",
        organizationName: ticket.organization_name ?? null,
        workType: ticket.work_type ?? "support",
        day: ticketSession.day
      });
      await load();
    } catch (error) {
      toast.error("Session konnte nicht nachgetragen werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setSavingTicketSession(false);
    }
  }

  function openSessionEditor(session: SessionEntry) {
    setEditingSession(session);
    setEditSessionOrganizationId(session.organization_id ?? "");
    setEditSessionOrganizationName(session.organization_name ?? null);
    setEditSessionActivity(session.activity);
    setEditSessionWorkType(session.work_type);
    setEditSessionDay(toDateLocalValue(session.started_at));
    setEditSessionStartTime(toTimeLocalValue(session.started_at));
    setEditSessionEndTime(toTimeLocalValue(session.ended_at));
  }

  async function saveSessionData(event: FormEvent) {
    event.preventDefault();

    if (!editingSession) {
      return;
    }

    if (!editSessionOrganizationId) {
      toast.error("Organisation wählen");
      return;
    }

    const startedAt = new Date(`${editSessionDay}T${editSessionStartTime}:00`);
    const endedAt = new Date(`${editSessionDay}T${editSessionEndTime}:00`);

    if (Number.isNaN(startedAt.getTime()) || Number.isNaN(endedAt.getTime())) {
      toast.error("Beginn und Ende prüfen");
      return;
    }

    if (endedAt <= startedAt) {
      toast.error("Ende muss nach Beginn liegen");
      return;
    }

    setSavingSessionDetails(true);
    try {
      await updateSessionDetails(editingSession.id, {
        organizationId: editSessionOrganizationId,
        activity: editSessionActivity,
        workType: editSessionWorkType,
        startedAt: startedAt.toISOString(),
        endedAt: endedAt.toISOString()
      });
      toast.success("Session aktualisiert");
      setEditingSession(null);
      await load();
    } catch (error) {
      toast.error("Session konnte nicht gespeichert werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setSavingSessionDetails(false);
    }
  }

  async function removeSession(session: SessionEntry) {
    const confirmed = window.confirm(`Session vom ${formatDateTime(session.started_at)} wirklich löschen?`);

    if (!confirmed) {
      return;
    }

    setDeletingId(session.id);
    try {
      const result = await deleteSession(session.id);

      if (result.deleted.ticketDeleted || result.deleted.userTicketEmpty) {
        toast.success("Letzte Session gelöscht", {
          description: result.deleted.ticketDeleted ? "Das leere Ticket wurde entfernt." : "Für dich gibt es zu diesem Ticket keine Einträge mehr."
        });
        onNavigate("/analysis");
        return;
      }

      toast.success("Session gelöscht", {
        description: "Betroffene Abschlüsse wurden wieder geöffnet."
      });
      await load();
    } catch (error) {
      toast.error("Session konnte nicht gelöscht werden", {
        description: error instanceof Error ? error.message : "Unbekannter Fehler"
      });
    } finally {
      setDeletingId(null);
    }
  }

  return (
    <div className="space-y-4">
      <div className="flex flex-col gap-3 lg:flex-row lg:items-end lg:justify-between">
        <div>
          <Button variant="ghost" size="sm" className="-ml-2 mb-1 h-8" onClick={() => onNavigate("/analysis")}>
            <ArrowLeft className="size-4" />
            Zur Auswertung
          </Button>
          <div className="flex flex-wrap items-center gap-2">
            <h2 className="text-xl font-semibold tracking-normal sm:text-2xl">{ticket?.ticket_number ?? "Ticket"}</h2>
            {ticket?.ticket_number ? <CopyTicketButton ticketNumber={ticket.ticket_number} /> : null}
            {(periodType === "month" || (isGlobalTicket && globalMonthFilter !== "all")) && data?.closed ? <Badge variant="outline">Monat geschlossen</Badge> : null}
          </div>
          <p className="text-sm text-muted-foreground">Sessions {sessionsScopeLabel}</p>
        </div>

        <Badge variant={data?.openCount === 0 ? "success" : "warning"}>
          {data?.openCount === 0 ? "Bewertet" : `${data?.openCount ?? 0} offen`}
        </Badge>
      </div>

      {(periodType === "month" || (isGlobalTicket && globalMonthFilter !== "all")) && data?.closed ? (
        <Alert variant="success" className="py-3 text-sm">
          Dieser Monat ist abgeschlossen. Bewertungen und Änderungen sind geschützt, bis du den Monat im Monatsabschluss wieder öffnest.
        </Alert>
      ) : null}

      {isGlobalTicket ? (
        <Card>
          <CardHeader className="p-4">
            <CardTitle>Filter</CardTitle>
            <CardDescription>Grenzt die Sessionliste dieses Tickets ein. Die Ticketdaten selbst bleiben global.</CardDescription>
          </CardHeader>
          <CardContent className="grid gap-3 px-4 pb-4 md:grid-cols-3">
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="ticket-month-filter">Monat</label>
              <select
                id="ticket-month-filter"
                className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                value={globalMonthFilter}
                onChange={(event) => setGlobalMonthFilter(event.currentTarget.value)}
              >
                <option value="all">Alle Monate</option>
                {globalMonthFilter !== "all" && !selectedMonthHasSessions ? <option value={globalMonthFilter}>{globalMonthFilter} (0)</option> : null}
                {availableMonths.map((month) => (
                  <option key={month.month} value={month.month}>
                    {month.month} ({month.session_count})
                  </option>
                ))}
              </select>
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="ticket-status-filter">Bewertung</label>
              <select
                id="ticket-status-filter"
                className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                value={globalStatusFilter}
                onChange={(event) => setGlobalStatusFilter(event.currentTarget.value as typeof globalStatusFilter)}
              >
                <option value="all">Alle Bewertungen</option>
                <option value="open">Offen</option>
                <option value="billed">Abgerechnet</option>
                <option value="non_billable">Nicht abrechenbar</option>
              </select>
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="ticket-source-filter">Quelle</label>
              <select
                id="ticket-source-filter"
                className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                value={globalSourceFilter}
                onChange={(event) => setGlobalSourceFilter(event.currentTarget.value as typeof globalSourceFilter)}
              >
                <option value="all">Alle Quellen</option>
                <option value="manual">Manuell</option>
                <option value="recurring">Fixe Abrechnung</option>
              </select>
            </div>
          </CardContent>
        </Card>
      ) : null}

      <Card>
        <CardHeader className="p-4">
          <div className="flex items-start justify-between gap-3">
            <div>
              <CardTitle>Ticketdaten</CardTitle>
              <CardDescription>Änderungen an Organisation und Art werden auf alle vorhandenen Sessions dieses Tickets übernommen.</CardDescription>
            </div>
            <HelpLink anchor="ticketdaten" label="Hilfe zu Ticketdaten" />
          </div>
        </CardHeader>
        <CardContent className="px-4 pb-4">
          <form className="grid gap-3 lg:grid-cols-[180px_minmax(220px,1fr)_180px_auto] lg:items-end" onSubmit={saveTicketData}>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="edit-ticket-number">Ticketnummer</label>
              <Input id="edit-ticket-number" value={editTicketNumber} onChange={(event) => setEditTicketNumber(event.currentTarget.value)} required />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="edit-ticket-organization">Organisation</label>
              {ticket?.customer_name && !ticket.organization_id ? (
                <p className="text-xs text-muted-foreground">Bisheriger Freitext: {ticket.customer_name}</p>
              ) : null}
              <OrganizationSelect
                value={editOrganizationId}
                selectedName={editOrganizationName}
                onChange={(organization) => {
                  setEditOrganizationId(organization.id);
                  setEditOrganizationName(organization.name);
                }}
                required
              />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="edit-ticket-work-type">Art</label>
              <select
                id="edit-ticket-work-type"
                className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                value={editWorkType}
                onChange={(event) => setEditWorkType(event.currentTarget.value as WorkType)}
              >
                <option value="support">Support</option>
                <option value="consulting">Consulting</option>
              </select>
            </div>
            <Button type="submit" disabled={savingTicket}>
              <Save className="size-4" />
              {savingTicket ? "Speichert..." : "Speichern"}
            </Button>
          </form>
        </CardContent>
      </Card>

      <Card>
        <CardHeader className="gap-3 p-4 sm:flex-row sm:items-start sm:justify-between sm:space-y-0">
          <div>
            <CardTitle>Session-Einträge</CardTitle>
            <CardDescription>Wähle für jede Session genau eine Bewertung aus oder lösche falsche Einträge.</CardDescription>
          </div>
          <div className="flex flex-wrap items-center gap-2">
            <div className="flex items-center gap-2 rounded-md border bg-muted/30 px-3 py-2 text-sm">
              <span className="text-muted-foreground">Abgerechnet</span>
              <span className="font-semibold">{formatMinutes(periodTotalMinutes)}</span>
            </div>
            <div className="flex items-center gap-2 rounded-md border bg-muted/30 px-3 py-2 text-sm">
              <span className="text-muted-foreground">{teamspaceLabel}</span>
              <span className="font-semibold">{formatMinutes(periodTeamspaceMinutes)}</span>
            </div>
            <HelpLink anchor="ticketdetail" label="Hilfe zur Ticketdetailansicht" />
          </div>
        </CardHeader>
        <CardContent className="px-4 pb-4">
          <div className="space-y-3">
            {sessionGroups.map((group) => (
              <div key={group.key} className="rounded-md border bg-background">
                <div className="flex flex-col gap-2 border-b bg-muted/40 px-3 py-2 sm:flex-row sm:items-center sm:justify-between">
                  <p className="font-medium">{group.label}</p>
                  <div className="flex flex-wrap items-center gap-2">
                    <Badge variant="outline">Tag abgerechnet {formatMinutes(group.totalMinutes)}</Badge>
                    {group.nonBillableMinutes > 0 ? <Badge variant="secondary">Nicht {formatMinutes(group.nonBillableMinutes)}</Badge> : null}
                    {group.openMinutes > 0 ? <Badge variant="warning">Offen {formatMinutes(group.openMinutes)}</Badge> : null}
                    <div className="flex items-center gap-2 text-xs text-muted-foreground">
                      <label htmlFor={`crm-billing-${group.key}`}>Teamspace</label>
                      <Input
                        id={`crm-billing-${group.key}`}
                        type="text"
                        className="h-7 w-24 bg-background text-right"
                        autoComplete="off"
                        inputMode="decimal"
                        value={dayBillingInputs[group.key] ?? ""}
                        disabled={isPeriodClosed || savingDayBillingKey === group.key}
                        placeholder="0"
                        onChange={(event) => {
                          const nextValue = event.currentTarget.value;

                          if (!isPartialHoursInput(nextValue)) {
                            return;
                          }

                          setDayBillingInputs((current) => ({
                            ...current,
                            [group.key]: nextValue
                          }));
                        }}
                        onKeyDown={(event) => {
                          if (event.key === "Enter") {
                            event.preventDefault();
                          }
                        }}
                      />
                      <span>h</span>
                      <Button
                        type="button"
                        size="sm"
                        className={cn("h-7 w-[104px]", !isDayBillingDirty(group.key) && "invisible")}
                        disabled={isPeriodClosed || !isDayBillingDirty(group.key) || savingDayBillingKey === group.key}
                        onMouseDown={(event) => event.preventDefault()}
                        onClick={() => void saveDayBilling(group.key)}
                      >
                        <Save className="size-3.5" />
                        {savingDayBillingKey === group.key ? "Speichert..." : "Speichern"}
                      </Button>
                    </div>
                  </div>
                </div>
                <div className="space-y-1.5 p-2 sm:p-3">
                  {group.sessions.map((session) => (
                    <div key={session.id} className="ml-3 rounded-md border bg-card/40 p-2 sm:ml-6">
                      <div className="grid gap-2 lg:grid-cols-[140px_minmax(0,1fr)_90px_auto_auto] lg:items-center">
                        <div className="text-sm text-muted-foreground">
                          {formatTimeRange(session.started_at, session.ended_at)}
                        </div>
                        <div className="min-w-0">
                          <p className="whitespace-pre-wrap break-words text-sm font-medium">{session.activity}</p>
                        </div>
                        <div className="flex flex-wrap gap-1">
                          <Badge variant="outline" className="w-fit">{formatMinutes(session.rounded_minutes)}</Badge>
                          {session.recurring_billing_id ? <Badge variant="secondary">fix</Badge> : null}
                        </div>
                        <BillingButtons
                          session={session}
                          disabled={isPeriodClosed}
                          loading={loadingId === session.id}
                          onChange={(value) => setBilling(session.id, value)}
                        />
                        <div className="flex gap-1 lg:justify-end">
                          <Button size="icon" variant="ghost" className="size-8" onClick={() => openSessionEditor(session)}>
                            <Pencil className="size-4" />
                            <span className="sr-only">Session bearbeiten</span>
                          </Button>
                          <Button
                            size="icon"
                            variant="ghost"
                            className="size-8 text-destructive hover:text-destructive"
                            disabled={deletingId === session.id}
                            onClick={() => removeSession(session)}
                          >
                            <Trash2 className="size-4" />
                            <span className="sr-only">Session löschen</span>
                          </Button>
                        </div>
                      </div>
                    </div>
                  ))}
                </div>
              </div>
            ))}
          </div>

          {data?.sessions.length === 0 ? (
            <p className="py-8 text-center text-sm text-muted-foreground">Keine Sessions für dieses Ticket im gewählten Filter.</p>
          ) : null}
        </CardContent>
      </Card>
      <Card>
        <CardHeader className="p-4">
          <div className="flex items-start justify-between gap-3">
            <div>
              <CardTitle>Session nachtragen</CardTitle>
              <CardDescription>Neue Zeit direkt diesem Ticket zuordnen.</CardDescription>
            </div>
            <HelpLink anchor="session-nachtragen" label="Hilfe zum Nachtragen von Sessions" />
          </div>
        </CardHeader>
        <CardContent className="px-4 pb-4">
          <form className="space-y-4" onSubmit={submitTicketSession}>
            {ticket?.organization_id && ticket.work_type ? (
              <div className="grid gap-2 rounded-md border bg-muted/30 p-3 text-sm sm:grid-cols-[1fr_auto] sm:items-center">
                <span className="font-medium">{ticket.organization_name ?? ticket.customer_name}</span>
                <Badge variant="outline">{ticket.work_type === "support" ? "Support" : "Consulting"}</Badge>
              </div>
            ) : (
              <div className="grid gap-3 lg:grid-cols-[minmax(220px,1fr)_180px]">
                <div className="space-y-2">
                  <label className="text-sm font-medium">Organisation</label>
                  {ticket?.customer_name && !ticket.organization_id ? (
                    <p className="text-xs text-muted-foreground">Bisheriger Freitext: {ticket.customer_name}</p>
                  ) : null}
                  <OrganizationSelect
                    value={ticketSession.organizationId}
                    selectedName={ticketSession.organizationName}
                    onChange={(organization) =>
                      setTicketSession({
                        ...ticketSession,
                        organizationId: organization.id,
                        organizationName: organization.name
                      })
                    }
                    required
                  />
                </div>
                <div className="space-y-2">
                  <label className="text-sm font-medium" htmlFor="ticket-session-work-type">
                    Art
                  </label>
                  <select
                    id="ticket-session-work-type"
                    className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                    value={ticketSession.workType}
                    onChange={(event) => setTicketSession({ ...ticketSession, workType: event.currentTarget.value as WorkType })}
                  >
                    <option value="support">Support</option>
                    <option value="consulting">Consulting</option>
                  </select>
                </div>
              </div>
            )}

            <div className="grid gap-3 lg:grid-cols-[150px_120px_120px_minmax(220px,1fr)_auto] lg:items-end">
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="ticket-session-day">
                  Datum
                </label>
                <Input
                  id="ticket-session-day"
                  type="date"
                  value={ticketSession.day}
                  onChange={(event) => setTicketSession({ ...ticketSession, day: event.currentTarget.value })}
                  required
                />
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="ticket-session-start">
                  Von
                </label>
                <Input
                  id="ticket-session-start"
                  type="time"
                  value={ticketSession.startTime}
                  onChange={(event) => setTicketSession({ ...ticketSession, startTime: event.currentTarget.value })}
                  required
                />
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="ticket-session-end">
                  Bis
                </label>
                <Input
                  id="ticket-session-end"
                  type="time"
                  value={ticketSession.endTime}
                  onChange={(event) => setTicketSession({ ...ticketSession, endTime: event.currentTarget.value })}
                  required
                />
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="ticket-session-activity">
                  Tätigkeit
                </label>
                <Textarea
                  id="ticket-session-activity"
                  className="min-h-20"
                  value={ticketSession.activity}
                  onChange={(event) => setTicketSession({ ...ticketSession, activity: event.currentTarget.value })}
                  required
                />
              </div>
              <Button type="submit" disabled={savingTicketSession}>
                <Save className="size-4" />
                {savingTicketSession ? "Speichert..." : "Nachtragen"}
              </Button>
            </div>
          </form>
        </CardContent>
      </Card>

      
      {data && data.openCount > 0 ? (
        <p className="text-sm text-muted-foreground">
          Noch {data.openCount} Session(s) ohne Auswahl. Erst wenn im Monat keine Sessions mehr offen sind, kann der Monat abgeschlossen werden.
        </p>
      ) : null}

      <Dialog open={Boolean(editingSession)} onOpenChange={(open) => !open && setEditingSession(null)}>
        <DialogContent className="max-h-[calc(100dvh-2rem)] w-[calc(100vw-2rem)] overflow-y-auto p-5 sm:max-w-2xl">
          <DialogHeader className="pr-8">
            <DialogTitle>Session bearbeiten</DialogTitle>
            <DialogDescription>Beginn, Ende, Tätigkeit und Stammdaten dieses Eintrags nachträglich korrigieren.</DialogDescription>
          </DialogHeader>
          <form className="space-y-4 overflow-x-hidden" onSubmit={saveSessionData}>
            <div className="grid gap-3 sm:grid-cols-3">
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="session-day">Datum</label>
                <Input
                  id="session-day"
                  type="date"
                  value={editSessionDay}
                  onChange={(event) => setEditSessionDay(event.currentTarget.value)}
                  required
                />
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="session-start-time">Von</label>
                <Input
                  id="session-start-time"
                  type="time"
                  value={editSessionStartTime}
                  onChange={(event) => setEditSessionStartTime(event.currentTarget.value)}
                  required
                />
              </div>
              <div className="space-y-2">
                <label className="text-sm font-medium" htmlFor="session-end-time">Bis</label>
                <Input
                  id="session-end-time"
                  type="time"
                  value={editSessionEndTime}
                  onChange={(event) => setEditSessionEndTime(event.currentTarget.value)}
                  required
                />
              </div>
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="session-organization">Organisation</label>
              {editingSession?.customer_name && !editingSession.organization_id ? (
                <p className="text-xs text-muted-foreground">Bisheriger Freitext: {editingSession.customer_name}</p>
              ) : null}
              <OrganizationSelect
                value={editSessionOrganizationId}
                selectedName={editSessionOrganizationName}
                onChange={(organization) => {
                  setEditSessionOrganizationId(organization.id);
                  setEditSessionOrganizationName(organization.name);
                }}
                required
              />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="session-activity">Tätigkeit</label>
              <Textarea
                id="session-activity"
                className="min-h-24 resize-y"
                value={editSessionActivity}
                onChange={(event) => setEditSessionActivity(event.currentTarget.value)}
                required
              />
            </div>
            <div className="space-y-2">
              <label className="text-sm font-medium" htmlFor="session-work-type">Art</label>
              <select
                id="session-work-type"
                className="h-8 w-full rounded-lg border border-input bg-background px-2 text-sm focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
                value={editSessionWorkType}
                disabled={Boolean(editingSession?.recurring_billing_id)}
                onChange={(event) => setEditSessionWorkType(event.currentTarget.value as WorkType)}
              >
                <option value="support">Support</option>
                <option value="consulting">Consulting</option>
              </select>
            </div>
            <div className="flex justify-end">
              <Button type="submit" disabled={savingSessionDetails}>
                <Save className="size-4" />
                {savingSessionDetails ? "Speichert..." : "Session speichern"}
              </Button>
            </div>
          </form>
        </DialogContent>
      </Dialog>
    </div>
  );
}