"use client";
 import React from "react";
 import { useRouter } from "next/navigation";
 import { api } from "@/lib/api";
 import { Input } from "@/components/ui/input";
 import { Button } from "@/components/ui/button";

 export default function TransmittalNew() {
   const router = useRouter();
   const [draftId, setDraftId] = React.useState(null);
   const [saving, setSaving] = React.useState(false);
   const [savedAt, setSavedAt] = React.useState(null);
   const [error, setError] = React.useState("");
   const [form, setForm] = React.useState({
     subject: "", number: "", to_party: "", sent_date: "", description: ""
   });
   const [errs, setErrs] = React.useState({});

   const validate = (f) => {
     const e = {};
     if (!f.subject?.trim()) e.subject = "กรุณากรอกเรื่อง (Subject)";
     if (!f.to_party?.trim()) e.to_party = "กรุณาระบุผู้รับ (To)";
     if (!f.sent_date) e.sent_date = "กรุณาระบุวันที่ส่ง";
     return e;
   };

   const tRef = React.useRef(0);
   React.useEffect(() => {
     clearTimeout(tRef.current);
     tRef.current = window.setTimeout(async () => {
       const e = validate(form);
       setErrs(e);
       try {
         setSaving(true);
         if (!draftId) {
           const res = await api("/transmittals", { method: "POST", body: { ...form, status: "draft" } });
           setDraftId(res.id);
         } else {
           await api(`/transmittals/${draftId}`, { method: "PATCH", body: { ...form, status: "draft" } });
         }
         setSavedAt(new Date());
       } catch (err) {
         setError(err.message || "บันทึกฉบับร่างไม่สำเร็จ");
       } finally {
         setSaving(false);
       }
     }, 800);
     return () => clearTimeout(tRef.current);
   }, [form, draftId]);

   const onSubmit = async (e) => {
     e.preventDefault();
     const eobj = validate(form);
     setErrs(eobj);
     if (Object.keys(eobj).length) return;
     try {
       setSaving(true);
       const id = draftId
         ? (await api(`/transmittals/${draftId}`, { method: "PATCH", body: { ...form, status: "submitted" } })).id || draftId
         : (await api("/transmittals", { method: "POST", body: { ...form, status: "submitted" } })).id;
       router.replace(`/transmittals`);
     } catch (err) {
       setError(err.message || "ส่ง Transmittal ไม่สำเร็จ");
     } finally {
       setSaving(false);
     }
   };

   return (
     <form onSubmit={onSubmit} className="space-y-4 rounded-2xl p-5 bg-white">
       <div className="text-lg font-semibold">สร้าง Transmittal</div>
       {error && <div className="text-sm text-red-600">{error}</div>}
       <div className="grid md:grid-cols-2 gap-3">
         <div>
           <label className="text-sm">เรื่อง (Subject) *</label>
           <Input value={form.subject} onChange={(e)=>setForm(f=>({...f, subject:e.target.value}))}/>
           {errs.subject && <div className="text-xs text-red-600 mt-1">{errs.subject}</div>}
         </div>
         <div>
           <label className="text-sm">เลขที่ (ถ้ามี)</label>
           <Input value={form.number} onChange={(e)=>setForm(f=>({...f, number:e.target.value}))}/>
         </div>
         <div>
           <label className="text-sm">ถึง (To) *</label>
           <Input value={form.to_party} onChange={(e)=>setForm(f=>({...f, to_party:e.target.value}))}/>
           {errs.to_party && <div className="text-xs text-red-600 mt-1">{errs.to_party}</div>}
         </div>
         <div>
           <label className="text-sm">วันที่ส่ง *</label>
           <input type="date" className="border rounded-xl p-2 w-full" value={form.sent_date}
                  onChange={(e)=>setForm(f=>({...f, sent_date:e.target.value}))}/>
           {errs.sent_date && <div className="text-xs text-red-600 mt-1">{errs.sent_date}</div>}
         </div>
       </div>
       <div>
         <label className="text-sm">รายละเอียด</label>
         <textarea rows={5} className="border rounded-xl p-2 w-full"
                   value={form.description} onChange={(e)=>setForm(f=>({...f, description:e.target.value}))}/>
       </div>
       <div className="flex items-center gap-3">
         <Button type="submit" disabled={saving}>ส่ง Transmittal</Button>
         <span className="text-sm opacity-70">
           {saving ? "กำลังบันทึก…" : savedAt ? `บันทึกล่าสุด ${savedAt.toLocaleTimeString()}` : "ยังไม่เคยบันทึก"}
         </span>
       </div>
     </form>
   );
 }