"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";
import { managerEditPo } from "./manager-po-edit-actions";
import { LineItemsEditor } from "@/components/po/po-line-items-editor";
import { TC_DEFAULTS, TC_FIXED_LINE } from "@/lib/validations/po";
import type { LineItemInput } from "@/lib/validations/po";
import type { Vendor, PurchaseOrder } from "@prisma/client";
import type { CostCentreOption, AccountGroup } from "@/app/(portal)/po/new/new-po-form";

type SerializedLineItem = {
  id: string;
  poId: string;
  name: string;
  description: string | null;
  quantity: number;
  unit: string;
  size: string | null;
  unitPrice: number;
  totalPrice: number;
  gstRate: number;
  sortOrder: number;
  productId: string | null;
};

type PoFull = Omit<PurchaseOrder, "totalAmount"> & {
  totalAmount: number;
  lineItems: SerializedLineItem[];
  vessel: { id: string; name: string } | null;
  account: { id: string; name: string; code: string };
  vendor: { id: string; name: string; vendorId: string | null } | null;
};

interface Props {
  po: PoFull;
  costCentres: CostCentreOption[];
  initialCostCentreRef: string;
  accounts: AccountGroup[];
  vendors: Vendor[];
}

const INPUT =
  "w-full rounded-lg border border-amber-300 bg-amber-50 px-3 py-2 text-sm focus:border-amber-500 focus:outline-none focus:ring-2 focus:ring-amber-400/30 placeholder:text-neutral-400";
const LABEL = "block text-xs font-semibold text-amber-800 mb-1";

export function ManagerEditPoForm({ po, costCentres, initialCostCentreRef, accounts, vendors }: Props) {
  const router = useRouter();
  const [editing, setEditing] = useState(false);
  const [pending, setPending] = useState(false);
  const [error, setError] = useState("");
  const [saved, setSaved] = useState(false);

  const extPo = po as typeof po & {
    piQuotationNo?: string | null; piQuotationDate?: Date | null;
    requisitionNo?: string | null; requisitionDate?: Date | null;
    placeOfDelivery?: string | null;
    tcDelivery?: string | null; tcDispatch?: string | null;
    tcInspection?: string | null; tcTransitInsurance?: string | null;
    tcPaymentTerms?: string | null; tcOthers?: string | null;
  };

  const [lineItems, setLineItems] = useState<LineItemInput[]>(
    po.lineItems.map((li) => ({
      name: li.name,
      description: li.description ?? undefined,
      quantity: li.quantity,
      unit: li.unit,
      size: li.size ?? undefined,
      unitPrice: li.unitPrice,
      gstRate: li.gstRate,
    }))
  );

  function isoDate(d: Date | null | undefined) {
    if (!d) return "";
    return new Date(d).toISOString().split("T")[0];
  }

  async function handleSave() {
    setPending(true);
    setError("");
    const form = document.getElementById("mgr-edit-po-form") as HTMLFormElement;
    const data = new FormData(form);
    lineItems.forEach((item, i) => {
      data.set(`lineItems[${i}].name`, item.name);
      data.set(`lineItems[${i}].description`, item.description ?? "");
      data.set(`lineItems[${i}].quantity`, String(item.quantity));
      data.set(`lineItems[${i}].unit`, item.unit);
      data.set(`lineItems[${i}].size`, item.size ?? "");
      data.set(`lineItems[${i}].unitPrice`, String(item.unitPrice));
      data.set(`lineItems[${i}].gstRate`, String(item.gstRate ?? 0.18));
    });

    const result = await managerEditPo(po.id, data);
    if ("error" in result) {
      setError(result.error);
      setPending(false);
    } else {
      setSaved(true);
      setEditing(false);
      setPending(false);
      router.refresh();
    }
  }

  if (!editing) {
    return (
      <div className="mt-2 rounded-lg border border-amber-200 bg-amber-50 px-6 py-4">
        {saved && (
          <p className="mb-3 text-xs text-amber-700 bg-amber-100 border border-amber-200 rounded px-3 py-1.5">
            PO updated. Original values are preserved in the activity trail.
          </p>
        )}
        <button
          onClick={() => setEditing(true)}
          className="text-sm text-amber-700 hover:text-amber-900 font-semibold underline underline-offset-2"
        >
          ✏️ Edit PO (Manager)
        </button>
        <p className="mt-1 text-xs text-amber-600">
          Edit any field on this PO. Original values will be saved to the audit trail.
        </p>
      </div>
    );
  }

  return (
    <div className="mt-2 rounded-lg border-2 border-amber-400 bg-amber-50">
      {/* Header */}
      <div className="flex items-center justify-between px-6 py-4 border-b border-amber-200">
        <div>
          <p className="text-sm font-bold text-amber-800 uppercase tracking-wide">Manager — Editing PO</p>
          <p className="text-xs text-amber-600 mt-0.5">All changes will be saved to the audit trail with the original values.</p>
        </div>
        <button
          onClick={() => { setEditing(false); setError(""); }}
          className="text-xs text-amber-700 hover:text-amber-900 underline"
        >
          Cancel
        </button>
      </div>

      <form id="mgr-edit-po-form" className="p-6 space-y-6" onSubmit={(e) => e.preventDefault()}>

        {/* Order Information */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Order Information</h3>
          <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
            <div className="sm:col-span-2">
              <label className={LABEL}>Title <span className="text-danger">*</span></label>
              <input name="title" required defaultValue={po.title} className={INPUT} />
            </div>
            <div>
              <label className={LABEL}>Cost Centre <span className="text-danger">*</span></label>
              <select name="costCentreRef" required defaultValue={initialCostCentreRef} className={INPUT}>
                <optgroup label="Vessels">
                  {costCentres.filter((c) => c.group === "Vessels").map((c) => (
                    <option key={c.ref} value={c.ref}>{c.label}</option>
                  ))}
                </optgroup>
                <optgroup label="Sites">
                  {costCentres.filter((c) => c.group === "Sites").map((c) => (
                    <option key={c.ref} value={c.ref}>{c.label}</option>
                  ))}
                </optgroup>
              </select>
            </div>
            <div>
              <label className={LABEL}>Accounting Code <span className="text-danger">*</span></label>
              <select name="accountId" required defaultValue={po.accountId} className={INPUT}>
                {accounts.map(({ group, items }) => (
                  <optgroup key={group} label={group}>
                    {items.map((a) => <option key={a.id} value={a.id}>{a.code} — {a.name}</option>)}
                  </optgroup>
                ))}
              </select>
            </div>
            <div>
              <label className={LABEL}>Project Code</label>
              <input name="projectCode" defaultValue={po.projectCode ?? ""} className={INPUT} placeholder="Optional" />
            </div>
            <div>
              <label className={LABEL}>Delivery Date Required</label>
              <input name="dateRequired" type="date" defaultValue={isoDate(po.dateRequired)} className={INPUT} />
            </div>
          </div>
        </section>

        {/* Quotation Reference */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Quotation Reference</h3>
          <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
            <div>
              <label className={LABEL}>PI / Quotation No.</label>
              <input name="piQuotationNo" defaultValue={extPo.piQuotationNo ?? ""} className={INPUT} placeholder="e.g. Verbal" />
            </div>
            <div>
              <label className={LABEL}>PI / Quotation Date</label>
              <input name="piQuotationDate" type="date" defaultValue={isoDate(extPo.piQuotationDate)} className={INPUT} />
            </div>
          </div>
        </section>

        {/* Requisition */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Requisition</h3>
          <div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
            <div>
              <label className={LABEL}>Vessel / Office Requisition No.</label>
              <input name="requisitionNo" defaultValue={extPo.requisitionNo ?? ""} className={INPUT} placeholder="Optional" />
            </div>
            <div>
              <label className={LABEL}>Requisition Date</label>
              <input name="requisitionDate" type="date" defaultValue={isoDate(extPo.requisitionDate)} className={INPUT} />
            </div>
          </div>
        </section>

        {/* Delivery */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Delivery</h3>
          <label className={LABEL}>Place of Delivery</label>
          <textarea name="placeOfDelivery" rows={2} defaultValue={extPo.placeOfDelivery ?? ""} className={INPUT} />
        </section>

        {/* Vendor */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Vendor</h3>
          <label className={LABEL}>Vendor</label>
          <select name="vendorId" defaultValue={po.vendorId ?? ""} className={INPUT}>
            <option value="">No vendor selected</option>
            {vendors.map((v) => (
              <option key={v.id} value={v.id}>
                {v.name} {v.vendorId ? `(${v.vendorId})` : "(unverified)"}
              </option>
            ))}
          </select>
        </section>

        {/* Line Items */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Line Items</h3>
          <div className="rounded-lg border border-amber-200 bg-white p-4">
            <LineItemsEditor items={lineItems} onChange={setLineItems} />
          </div>
        </section>

        {/* Terms & Conditions */}
        <section>
          <h3 className="text-xs font-bold text-amber-800 uppercase tracking-wider mb-3">Terms &amp; Conditions</h3>
          <div className="space-y-2.5">
            <div className="rounded-lg bg-amber-100 border border-amber-200 px-3 py-2 text-xs text-amber-700 select-none">
              <span className="font-semibold">1.</span> {TC_FIXED_LINE}
            </div>
            {([
              { n: 2, label: "Delivery",             name: "tcDelivery",         key: "tcDelivery" },
              { n: 3, label: "Dispatch Instructions", name: "tcDispatch",         key: "tcDispatch" },
              { n: 4, label: "Inspection",            name: "tcInspection",       key: "tcInspection" },
              { n: 5, label: "Transit Insurance",     name: "tcTransitInsurance", key: "tcTransitInsurance" },
              { n: 6, label: "Payment Terms",         name: "tcPaymentTerms",     key: "tcPaymentTerms" },
            ] as const).map(({ n, label, name, key }) => (
              <div key={name} className="flex items-center gap-3">
                <span className="w-5 shrink-0 text-xs font-semibold text-amber-700 text-right">{n}.</span>
                <label className="w-44 shrink-0 text-xs font-semibold text-amber-800">{label}</label>
                <input
                  name={name}
                  defaultValue={(extPo[key] ?? TC_DEFAULTS[key]) as string}
                  className={INPUT}
                />
              </div>
            ))}
            <div className="flex items-start gap-3">
              <span className="w-5 shrink-0 text-xs font-semibold text-amber-700 text-right mt-2">7.</span>
              <label className="w-44 shrink-0 text-xs font-semibold text-amber-800 mt-2">Others</label>
              <textarea
                name="tcOthers"
                rows={2}
                defaultValue={(extPo.tcOthers ?? TC_DEFAULTS.tcOthers) as string}
                className={INPUT}
              />
            </div>
          </div>
        </section>

        {error && (
          <p className="text-sm text-danger-700 bg-danger-50 rounded-lg px-3 py-2">{error}</p>
        )}

        <div className="flex items-center gap-3 pt-2 border-t border-amber-200">
          <button
            type="button"
            onClick={handleSave}
            disabled={pending}
            className="rounded-lg bg-amber-600 px-5 py-2.5 text-sm font-semibold text-white hover:bg-amber-700 disabled:opacity-60 transition-colors"
          >
            {pending ? "Saving…" : "Save Changes"}
          </button>
          <button
            type="button"
            onClick={() => { setEditing(false); setError(""); }}
            disabled={pending}
            className="rounded-lg border border-neutral-300 bg-white px-4 py-2.5 text-sm font-medium text-neutral-700 hover:bg-neutral-50 disabled:opacity-60"
          >
            Cancel
          </button>
        </div>
      </form>
    </div>
  );
}
