"use client";

import { zodResolver } from "@hookform/resolvers/zod";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { ChevronDown, Download, FileText, Plus, Save, ShieldCheck, UploadCloud, X } from "lucide-react";
import { useEffect, useMemo, useRef, useState } from "react";
import { Controller, useFieldArray, useForm, useWatch } from "react-hook-form";
import { z } from "zod";
import { useAuth } from "@/components/auth";
import { apiGet, apiSend, Contact, Customer, Device, Equipment, Location, Paginated, ValidationItem } from "@/lib/api";

const triState = ["yes", "no", "na"] as const;
const today = new Date().toISOString().slice(0, 10);

const checklistTexts = [
  "Gebrauchsanweisung und Herstellerdokumentation vorhanden",
  "Wartungsnachweise vollstaendig",
  "Kalibrierzertifikate der Pruefmittel gueltig",
  "Aufstellbedingungen dokumentiert",
  "Wasserqualitaet dokumentiert",
  "Chargendokumentation nachvollziehbar",
  "Routinekontrollen definiert",
  "Freigabeverfahren beschrieben",
  "Personal eingewiesen",
  "Abweichungen bewertet"
];

const performanceTexts = [
  "Vakuumtest entspricht Vorgaben",
  "Bowie-Dick / Leerkammerprofil entspricht Vorgaben",
  "Temperaturband innerhalb Spezifikation",
  "Haltezeit erreicht",
  "Druckverlauf plausibel",
  "Trocknungsergebnis akzeptabel",
  "Beladungsmuster reproduzierbar",
  "Sensorpositionen dokumentiert"
];

const attachmentCategories = [
  "Aufbereitungsraum",
  "reiner Bereich",
  "unreiner Bereich",
  "Sterilisator",
  "Beladung",
  "Sensorposition",
  "Chargenprotokoll",
  "Indikator",
  "Zertifikat",
  "Kalibrierschein",
  "Winlog-Auswertung"
];

const schema = z.object({
  report_number: z.string().min(3),
  validation_type: z.string().min(1),
  project: z.string().min(1),
  performed_on: z.string().min(1),
  test_location: z.string().min(1),
  examiner_name: z.string().min(1),
  participants: z.string().optional(),
  status: z.string().min(1),
  result: z.string().min(1),
  customer_id: z.string().min(1),
  location_id: z.string().optional().nullable(),
  contact_id: z.string().optional().nullable(),
  operator_name: z.string().optional(),
  device_id: z.string().min(1),
  equipment_ids: z.array(z.string()),
  environment_conditions: z.record(z.unknown()),
  documentation_checklist: z.array(z.record(z.unknown())),
  performance_checklist: z.array(z.record(z.unknown())),
  programs: z.array(z.record(z.unknown())),
  loading_patterns: z.array(z.record(z.unknown())),
  measurement_data: z.array(z.record(z.unknown())),
  drying: z.record(z.unknown()),
  recommendations: z.array(z.record(z.unknown())),
  attachments: z.array(z.record(z.unknown()))
});

type FormValues = z.infer<typeof schema>;

function checklist(items: string[]) {
  return items.map((text, index) => ({ number: index + 1, text, value: "na", comment: "" }));
}

function defaults(reportNumber = ""): FormValues {
  return {
    report_number: reportNumber,
    validation_type: "Erstvalidierung",
    project: "",
    performed_on: today,
    test_location: "",
    examiner_name: "",
    participants: "",
    status: "draft",
    result: "offen",
    customer_id: "",
    location_id: "",
    contact_id: "",
    operator_name: "",
    device_id: "",
    equipment_ids: [],
    environment_conditions: {
      room_temperature: "",
      humidity: "",
      test_time: "",
      checks: [
        { text: "Raumbedingungen stabil", value: "na", comment: "" },
        { text: "Aufstellort frei zugaenglich", value: "na", comment: "" },
        { text: "Medienversorgung verfuegbar", value: "na", comment: "" }
      ]
    },
    documentation_checklist: checklist(checklistTexts),
    performance_checklist: checklist(performanceTexts),
    programs: [
      { name: "Vakuumtest", selected: false, custom: false },
      { name: "Bowie-Dick / Leerkammerprofil", selected: false, custom: false },
      { name: "134 C hohl verpackt", selected: false, custom: false }
    ],
    loading_patterns: [1, 2, 3].map((run) => ({ run, pattern: "", description: "", images: [] })),
    measurement_data: ["Vakuumtest", "Leerkammerprofil", "Testlauf 1", "Testlauf 2", "Testlauf 3"].map((name) => ({
      name,
      start_time: "",
      end_time: "",
      duration: "",
      leak_rate: "",
      min_temperature: "",
      max_temperature: "",
      temperature_band: "",
      equilibration_time: "",
      holding_time: "",
      pressure: "",
      result: "",
      imports: []
    })),
    drying: { start_weight: "", end_weight: "", difference: "", rating: "", comment: "" },
    recommendations: [],
    attachments: []
  };
}

function Accordion({ title, children, defaultOpen = false }: { title: string; children: React.ReactNode; defaultOpen?: boolean }) {
  const [open, setOpen] = useState(defaultOpen);
  return (
    <section className="rounded-lg border border-border bg-surface shadow-soft">
      <button type="button" onClick={() => setOpen((value) => !value)} className="flex w-full items-center justify-between px-5 py-4 text-left text-lg font-semibold">
        {title}
        <ChevronDown className={`h-5 w-5 transition ${open ? "rotate-180" : ""}`} />
      </button>
      {open && <div className="border-t border-border p-5">{children}</div>}
    </section>
  );
}

function Field({ label, children }: { label: string; children: React.ReactNode }) {
  return <label className="block"><span className="text-sm font-medium text-text">{label}</span><div className="mt-2">{children}</div></label>;
}

const inputClass = "h-12 w-full rounded-lg border border-border bg-white px-4 outline-none focus:border-primary";
const selectClass = inputClass;
const areaClass = "min-h-24 w-full rounded-lg border border-border bg-white px-4 py-3 outline-none focus:border-primary";

export default function ValidationsPage() {
  const { token } = useAuth();
  const client = useQueryClient();
  const [draftId, setDraftId] = useState<string | null>(null);
  const [lastSaved, setLastSaved] = useState<string>("");
  const autosaveTimer = useRef<ReturnType<typeof setTimeout> | null>(null);

  const nextNumber = useQuery({ queryKey: ["next-report-number", token], queryFn: () => apiGet<{ report_number: string }>("/validations/next-report-number", token ?? ""), enabled: Boolean(token) });
  const customers = useQuery({ queryKey: ["customers-options", token], queryFn: () => apiGet<Paginated<Customer>>("/customers?page=1&page_size=100", token ?? ""), enabled: Boolean(token) });
  const locations = useQuery({ queryKey: ["locations-options", token], queryFn: () => apiGet<Paginated<Location>>("/locations?page=1&page_size=100", token ?? ""), enabled: Boolean(token) });
  const contacts = useQuery({ queryKey: ["contacts-options", token], queryFn: () => apiGet<Paginated<Contact>>("/contacts?page=1&page_size=100", token ?? ""), enabled: Boolean(token) });
  const devices = useQuery({ queryKey: ["devices-options", token], queryFn: () => apiGet<Paginated<Device>>("/devices?page=1&page_size=100", token ?? ""), enabled: Boolean(token) });
  const equipment = useQuery({ queryKey: ["equipment-options", token], queryFn: () => apiGet<Paginated<Equipment>>("/equipment?page=1&page_size=100", token ?? ""), enabled: Boolean(token) });

  const form = useForm<FormValues>({ resolver: zodResolver(schema), defaultValues: defaults() });
  const watched = useWatch({ control: form.control });
  const selectedDevice = devices.data?.items.find((item) => item.id === form.watch("device_id"));
  const selectedEquipment = equipment.data?.items.filter((item) => form.watch("equipment_ids").includes(item.id)) ?? [];
  const recommendations = useFieldArray({ control: form.control, name: "recommendations" });
  const attachments = useFieldArray({ control: form.control, name: "attachments" });

  useEffect(() => {
    if (nextNumber.data?.report_number && !form.getValues("report_number")) {
      form.setValue("report_number", nextNumber.data.report_number);
    }
  }, [form, nextNumber.data]);

  const saveMutation = useMutation({
    mutationFn: (values: FormValues) => apiSend<ValidationItem>(draftId ? `/validations/${draftId}` : "/validations", token ?? "", draftId ? "PUT" : "POST", values),
    onSuccess: (item) => {
      setDraftId(item.id);
      setLastSaved(new Date().toLocaleTimeString("de-DE", { hour: "2-digit", minute: "2-digit" }));
      client.invalidateQueries({ queryKey: ["dashboard"] });
    }
  });

  useEffect(() => {
    if (!token || !watched.report_number || !watched.customer_id || !watched.device_id || !watched.project || !watched.performed_on) return;
    if (autosaveTimer.current) clearTimeout(autosaveTimer.current);
    autosaveTimer.current = setTimeout(() => {
      const values = form.getValues();
      saveMutation.mutate(values);
    }, 2500);
    return () => {
      if (autosaveTimer.current) clearTimeout(autosaveTimer.current);
    };
  }, [form, saveMutation, token, watched]);

  const customerOptions = customers.data?.items ?? [];
  const selectedCustomer = customerOptions.find((item) => item.id === form.watch("customer_id"));
  const filteredLocations = (locations.data?.items ?? []).filter((item) => !form.watch("customer_id") || item.customer_id === form.watch("customer_id"));
  const filteredContacts = (contacts.data?.items ?? []).filter((item) => !form.watch("customer_id") || item.customer_id === form.watch("customer_id"));
  const filteredDevices = (devices.data?.items ?? []).filter((item) => !form.watch("customer_id") || item.customer_id === form.watch("customer_id"));

  const calibrationWarnings = useMemo(() => selectedEquipment.filter((item) => item.calibration_due_on && item.calibration_due_on < today), [selectedEquipment]);

  function submit(values: FormValues) {
    saveMutation.mutate(values);
  }

  function addFiles(files: FileList | null, category: string) {
    if (!files) return;
    Array.from(files).forEach((file, index) => attachments.append({ category, filename: file.name, description: "", order: attachments.fields.length + index + 1, preview: URL.createObjectURL(file) }));
  }

  return (
    <form onSubmit={form.handleSubmit(submit)} className="space-y-5 pb-28">
      <header>
        <h1 className="text-3xl font-semibold text-text">Validierungsbericht</h1>
        <p className="mt-2 text-text-light">Eine responsive Seite fuer Erfassung, Pruefung und Berichtserstellung.</p>
      </header>

      <Accordion title="1. Allgemeine Angaben" defaultOpen>
        <div className="grid gap-4 md:grid-cols-2">
          <Field label="Berichtsnummer"><input className={inputClass} {...form.register("report_number")} /></Field>
          <Field label="Validierungsart"><select className={selectClass} {...form.register("validation_type")}><option>Erstvalidierung</option><option>Revalidierung</option><option>Leistungsbeurteilung</option><option>Sonderpruefung</option></select></Field>
          <Field label="Projekt"><input className={inputClass} {...form.register("project")} /></Field>
          <Field label="Pruefdatum"><input type="date" className={inputClass} {...form.register("performed_on")} /></Field>
          <Field label="Pruefungsort"><input className={inputClass} {...form.register("test_location")} /></Field>
          <Field label="Pruefer"><input className={inputClass} {...form.register("examiner_name")} /></Field>
          <Field label="Mitwirkende Personen"><textarea className={areaClass} {...form.register("participants")} /></Field>
          <Field label="Status"><select className={selectClass} {...form.register("status")}><option value="draft">Entwurf</option><option value="in_progress">In Pruefung</option><option value="ready_for_report">Bericht bereit</option><option value="completed">Abgeschlossen</option></select></Field>
          <Field label="Gesamtergebnis"><select className={selectClass} {...form.register("result")}><option value="offen">Offen</option><option value="bestanden">Bestanden</option><option value="nicht_bestanden">Nicht bestanden</option><option value="mit_auflagen">Mit Auflagen</option></select></Field>
        </div>
      </Accordion>

      <Accordion title="2. Kunde und Standort">
        <div className="grid gap-4 md:grid-cols-2">
          <Field label="Kunde"><select className={selectClass} {...form.register("customer_id")}><option value="">Bitte waehlen</option>{customerOptions.map((item) => <option key={item.id} value={item.id}>{item.name}</option>)}</select></Field>
          <Field label="Standort"><select className={selectClass} {...form.register("location_id")}><option value="">Bitte waehlen</option>{filteredLocations.map((item) => <option key={item.id} value={item.id}>{item.name}</option>)}</select></Field>
          <Field label="Ansprechpartner"><select className={selectClass} {...form.register("contact_id")}><option value="">Bitte waehlen</option>{filteredContacts.map((item) => <option key={item.id} value={item.id}>{item.full_name}</option>)}</select></Field>
          <Field label="Betreiber"><input className={inputClass} {...form.register("operator_name")} /></Field>
          <Field label="QM-/Hygienebeauftragter"><input className={inputClass} value={[selectedCustomer?.quality_manager, selectedCustomer?.hygiene_officer].filter(Boolean).join(" / ")} readOnly /></Field>
        </div>
      </Accordion>

      <Accordion title="3. Geraet">
        <Field label="Geraet"><select className={selectClass} {...form.register("device_id")}><option value="">Bitte waehlen</option>{filteredDevices.map((item) => <option key={item.id} value={item.id}>{item.manufacturer} {item.model} - {item.serial_number}</option>)}</select></Field>
        <div className="mt-4 grid gap-4 md:grid-cols-3">{[
          ["Hersteller", selectedDevice?.manufacturer],
          ["Modell", selectedDevice?.model],
          ["Seriennummer", selectedDevice?.serial_number],
          ["Baujahr", selectedDevice?.year_built],
          ["Inbetriebnahme", selectedDevice?.commissioned_on],
          ["Kammervolumen", selectedDevice?.chamber_volume_liters],
          ["Dampferzeugung", selectedDevice?.steam_generation],
          ["Wasseraufbereitung", selectedDevice?.water_treatment],
          ["Dokumentation", selectedDevice?.documentation],
          ["Lieferant", selectedDevice?.supplier]
        ].map(([label, value]) => <div key={label as string} className="rounded-lg border border-border bg-background p-4"><p className="text-xs text-text-light">{label}</p><p className="mt-1 font-medium">{String(value ?? "-")}</p></div>)}</div>
      </Accordion>

      <Accordion title="4. Pruefmittel">
        <Controller control={form.control} name="equipment_ids" render={({ field }) => (
          <div className="grid gap-3 md:grid-cols-2">
            {(equipment.data?.items ?? []).map((item) => {
              const expired = Boolean(item.calibration_due_on && item.calibration_due_on < today);
              return <label key={item.id} className="flex items-start gap-3 rounded-lg border border-border p-4"><input type="checkbox" className="mt-1 h-5 w-5" checked={field.value.includes(item.id)} onChange={(event) => field.onChange(event.target.checked ? [...field.value, item.id] : field.value.filter((id: string) => id !== item.id))} /><span><strong>{item.kind}</strong><br />{item.serial_number} · {item.calibrated_on ?? "-"} · {item.status}{expired && <span className="ml-2 text-danger">Kalibrierung abgelaufen</span>}</span></label>;
            })}
          </div>
        )} />
        {calibrationWarnings.length > 0 && <p className="mt-4 rounded-lg border border-danger/30 bg-danger/5 p-4 text-danger">Mindestens ein ausgewaehltes Pruefmittel hat eine abgelaufene Kalibrierung.</p>}
      </Accordion>

      <Accordion title="5. Umgebungsbedingungen">
        <div className="grid gap-4 md:grid-cols-3">
          <Field label="Raumtemperatur"><input className={inputClass} {...form.register("environment_conditions.room_temperature")} /></Field>
          <Field label="relative Luftfeuchtigkeit"><input className={inputClass} {...form.register("environment_conditions.humidity")} /></Field>
          <Field label="Pruefzeit"><input className={inputClass} {...form.register("environment_conditions.test_time")} /></Field>
        </div>
        {[0, 1, 2].map((index) => <ChecklistRow key={index} form={form} path={`environment_conditions.checks.${index}`} />)}
      </Accordion>

      <Accordion title="6. Dokumentations- und Leistungschecklisten">
        <h3 className="font-semibold">Dokumentation</h3>{checklistTexts.map((_, index) => <ChecklistRow key={index} form={form} path={`documentation_checklist.${index}`} />)}
        <h3 className="mt-6 font-semibold">Leistung</h3>{performanceTexts.map((_, index) => <ChecklistRow key={index} form={form} path={`performance_checklist.${index}`} />)}
      </Accordion>

      <Accordion title="7. Programme">
        {[0, 1, 2].map((index) => <ProgramRow key={index} form={form} index={index} />)}
        <button type="button" onClick={() => form.setValue("programs", [...form.getValues("programs"), { name: "", selected: true, custom: true }])} className="mt-4 inline-flex items-center gap-2 rounded-lg border border-border px-4 py-3 font-semibold"><Plus className="h-4 w-4" /> Eigenes Programm</button>
      </Accordion>

      <Accordion title="8. Beladungsmuster">
        {[0, 1, 2].map((index) => <LoadingRun key={index} form={form} index={index} />)}
      </Accordion>

      <Accordion title="9. Messdaten">
        {[0, 1, 2, 3, 4].map((index) => <MeasurementBlock key={index} form={form} index={index} />)}
      </Accordion>

      <Accordion title="10. Trocknung">
        <div className="grid gap-4 md:grid-cols-2">
          {["start_weight", "end_weight", "difference", "rating"].map((name) => <Field key={name} label={name}><input className={inputClass} {...form.register(`drying.${name}`)} /></Field>)}
          <Field label="Bemerkung"><textarea className={areaClass} {...form.register("drying.comment")} /></Field>
        </div>
      </Accordion>

      <Accordion title="11. Empfehlungen und Auflagen">
        {recommendations.fields.map((field, index) => <div key={field.id} className="mb-3 grid gap-3 rounded-lg border border-border p-4 md:grid-cols-4"><input className={inputClass} placeholder="Nummer" {...form.register(`recommendations.${index}.number`)} /><input className={inputClass} placeholder="Text" {...form.register(`recommendations.${index}.text`)} /><input type="date" className={inputClass} {...form.register(`recommendations.${index}.deadline`)} /><input className={inputClass} placeholder="Status" {...form.register(`recommendations.${index}.status`)} /></div>)}
        <button type="button" onClick={() => recommendations.append({ number: recommendations.fields.length + 1, text: "", deadline: "", status: "offen" })} className="inline-flex items-center gap-2 rounded-lg border border-border px-4 py-3 font-semibold"><Plus className="h-4 w-4" /> Zeile hinzufuegen</button>
      </Accordion>

      <Accordion title="12. Bilder und Anlagen">
        <div className="grid gap-3 md:grid-cols-2">{attachmentCategories.map((category) => <label key={category} className="rounded-lg border border-dashed border-primary/40 p-4"><UploadCloud className="mb-2 h-5 w-5 text-primary" />{category}<input type="file" multiple className="mt-3 block w-full text-sm" onChange={(event) => addFiles(event.target.files, category)} /></label>)}</div>
        <div className="mt-5 grid gap-3 md:grid-cols-2">{attachments.fields.map((field, index) => <div key={field.id} className="rounded-lg border border-border p-4"><div className="flex justify-between gap-3"><strong>{String(form.watch(`attachments.${index}.filename`) ?? "")}</strong><button type="button" onClick={() => attachments.remove(index)}><X className="h-4 w-4 text-danger" /></button></div><input className={`${inputClass} mt-3`} placeholder="Beschreibung" {...form.register(`attachments.${index}.description`)} /><input className={`${inputClass} mt-3`} placeholder="Reihenfolge" {...form.register(`attachments.${index}.order`)} /></div>)}</div>
      </Accordion>

      <div className="fixed inset-x-0 bottom-0 z-40 border-t border-border bg-surface/95 px-4 py-3 shadow-soft backdrop-blur">
        <div className="mx-auto flex max-w-7xl flex-wrap items-center justify-between gap-3">
          <span className="text-sm text-text-light">{lastSaved ? `Automatisch gespeichert um ${lastSaved}` : "Autosave aktiv, sobald Pflichtfelder ausgefuellt sind."}</span>
          <div className="flex flex-wrap gap-2">
            <button type="submit" className="inline-flex h-12 items-center gap-2 rounded-lg border border-border px-4 font-semibold"><Save className="h-4 w-4" /> Entwurf speichern</button>
            <button type="button" onClick={() => form.setValue("status", "ready_for_report")} className="inline-flex h-12 items-center gap-2 rounded-lg border border-border px-4 font-semibold"><ShieldCheck className="h-4 w-4" /> Validierung pruefen</button>
            <button type="button" className="inline-flex h-12 items-center gap-2 rounded-lg bg-primary px-4 font-semibold text-white shadow-soft"><FileText className="h-4 w-4" /> Bericht erzeugen</button>
            <button type="button" className="inline-flex h-12 items-center gap-2 rounded-lg border border-border px-4 font-semibold"><Download className="h-4 w-4" /> Bericht herunterladen</button>
          </div>
        </div>
      </div>
    </form>
  );
}

function ChecklistRow({ form, path }: { form: ReturnType<typeof useForm<FormValues>>; path: string }) {
  return <div className="mt-3 grid gap-3 rounded-lg border border-border p-4 md:grid-cols-[1fr_180px_1fr]"><input className={inputClass} readOnly {...form.register(`${path}.text` as never)} /><select className={selectClass} {...form.register(`${path}.value` as never)}>{triState.map((value) => <option key={value} value={value}>{value === "yes" ? "Ja" : value === "no" ? "Nein" : "Nicht zutreffend"}</option>)}</select><input className={inputClass} placeholder="Kommentar" {...form.register(`${path}.comment` as never)} /></div>;
}

function ProgramRow({ form, index }: { form: ReturnType<typeof useForm<FormValues>>; index: number }) {
  return <div className="mb-3 grid gap-3 rounded-lg border border-border p-4 md:grid-cols-[80px_1fr]"><input type="checkbox" className="h-6 w-6" {...form.register(`programs.${index}.selected`)} /><input className={inputClass} {...form.register(`programs.${index}.name`)} /></div>;
}

function LoadingRun({ form, index }: { form: ReturnType<typeof useForm<FormValues>>; index: number }) {
  return <div className="mb-4 rounded-lg border border-border p-4"><h3 className="font-semibold">Testlauf {index + 1}</h3><div className="mt-3 grid gap-3 md:grid-cols-2"><input className={inputClass} placeholder="Beladungsmuster" {...form.register(`loading_patterns.${index}.pattern`)} /><input className={inputClass} placeholder="Beschreibung" {...form.register(`loading_patterns.${index}.description`)} /><input type="file" multiple className="rounded-lg border border-border p-3 md:col-span-2" /></div></div>;
}

function MeasurementBlock({ form, index }: { form: ReturnType<typeof useForm<FormValues>>; index: number }) {
  const fields = ["start_time", "end_time", "duration", "leak_rate", "min_temperature", "max_temperature", "temperature_band", "equilibration_time", "holding_time", "pressure", "result"];
  return <div className="mb-4 rounded-lg border border-border p-4"><h3 className="font-semibold">{String(form.watch(`measurement_data.${index}.name`) ?? "")}</h3><div className="mt-3 grid gap-3 md:grid-cols-3">{fields.map((field) => <input key={field} className={inputClass} placeholder={field} {...form.register(`measurement_data.${index}.${field}`)} />)}<input type="file" multiple accept=".csv,.pdf" className="rounded-lg border border-border p-3 md:col-span-3" /></div></div>;
}