"use client";

import { useActionState, useEffect, useState } from "react";
import { Loader2, Save } from "lucide-react";
import { toast } from "sonner";

import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select";
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetFooter,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet";
import { Textarea } from "@/components/ui/textarea";
import { createLoanAction } from "@/lib/appwrite/loan-actions";
import { initialLoanState } from "@/lib/appwrite/loan-types";
import { formatTRY } from "@/lib/format";
import { ScopeToggle } from "@/components/finance/scope-toggle";

import type { BankAccountOption } from "./types";

const NONE = "__none__";

function computeMonthly(principal: number, ratePct: number, n: number): number {
  if (!principal || !n) return 0;
  const r = ratePct / 100;
  if (r === 0) return Number((principal / n).toFixed(2));
  const factor = Math.pow(1 + r, n);
  return Number(((principal * r * factor) / (factor - 1)).toFixed(2));
}

export function LoanFormSheet({
  open,
  onOpenChange,
  bankAccounts,
}: {
  open: boolean;
  onOpenChange: (v: boolean) => void;
  bankAccounts: BankAccountOption[];
}) {
  const [state, formAction, isPending] = useActionState(createLoanAction, initialLoanState);
  const [principal, setPrincipal] = useState(0);
  const [rate, setRate] = useState(2.5);
  const [term, setTerm] = useState(24);

  useEffect(() => {
    if (state.ok) {
      toast.success("Kredi kaydedildi, taksitler oluşturuldu.");
      onOpenChange(false);
    } else if (state.error) {
      toast.error(state.error);
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [state]);

  const monthly = computeMonthly(principal, rate, term);
  const total = monthly * term;
  const today = new Date().toISOString().slice(0, 10);

  return (
    <Sheet open={open} onOpenChange={onOpenChange}>
      <SheetContent className="flex w-full flex-col gap-0 p-0 sm:max-w-xl">
        <SheetHeader className="border-b px-6 py-4">
          <SheetTitle>Yeni kredi</SheetTitle>
          <SheetDescription>
            Kaydedince {term || 0} adet taksit otomatik hesaplanır ve eklenir.
          </SheetDescription>
        </SheetHeader>

        <form
          action={(fd) => {
            if (fd.get("bankAccountId") === NONE) fd.set("bankAccountId", "");
            formAction(fd);
          }}
          className="flex flex-1 flex-col"
        >
          <div className="flex-1 space-y-4 overflow-y-auto px-6 py-5">
            <ScopeToggle />

            <div className="grid gap-4 md:grid-cols-2">
              <div className="grid gap-2">
                <Label htmlFor="bankName">Banka *</Label>
                <Input id="bankName" name="bankName" required placeholder="Garanti BBVA" />
                {state.fieldErrors?.bankName && (
                  <p className="text-destructive text-xs">{state.fieldErrors.bankName}</p>
                )}
              </div>
              <div className="grid gap-2">
                <Label htmlFor="loanType">Tür</Label>
                <Select name="loanType" defaultValue="consumer">
                  <SelectTrigger id="loanType">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="consumer">İhtiyaç</SelectItem>
                    <SelectItem value="vehicle">Taşıt</SelectItem>
                    <SelectItem value="housing">Konut</SelectItem>
                    <SelectItem value="commercial">Ticari</SelectItem>
                    <SelectItem value="kmh">KMH</SelectItem>
                    <SelectItem value="other">Diğer</SelectItem>
                  </SelectContent>
                </Select>
              </div>
            </div>

            <div className="grid gap-2">
              <Label htmlFor="loanName">Kredi adı *</Label>
              <Input id="loanName" name="loanName" required placeholder="Örn. Ofis kredisi" />
            </div>

            <div className="grid gap-2">
              <Label htmlFor="bankAccountId">Bağlı hesap</Label>
              <Select name="bankAccountId" defaultValue={NONE} disabled={bankAccounts.length === 0}>
                <SelectTrigger id="bankAccountId">
                  <SelectValue placeholder={bankAccounts.length === 0 ? "Önce hesap ekleyin" : "Yok"} />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value={NONE}>Yok</SelectItem>
                  {bankAccounts.map((b) => (
                    <SelectItem key={b.id} value={b.id}>
                      {b.label}
                    </SelectItem>
                  ))}
                </SelectContent>
              </Select>
              <p className="text-muted-foreground text-xs">
                Taksit ödemeleri seçilen hesaba expense olarak yazılır.
              </p>
            </div>

            <div className="grid gap-4 md:grid-cols-3">
              <div className="grid gap-2">
                <Label htmlFor="principal">Anapara (₺) *</Label>
                <Input
                  id="principal"
                  name="principal"
                  type="number"
                  step="0.01"
                  min="0.01"
                  required
                  value={principal || ""}
                  onChange={(e) => setPrincipal(Number(e.target.value) || 0)}
                />
                {state.fieldErrors?.principal && (
                  <p className="text-destructive text-xs">{state.fieldErrors.principal}</p>
                )}
              </div>
              <div className="grid gap-2">
                <Label htmlFor="interestRate">Aylık faiz %</Label>
                <Input
                  id="interestRate"
                  name="interestRate"
                  type="number"
                  step="0.01"
                  min="0"
                  max="100"
                  required
                  value={rate}
                  onChange={(e) => setRate(Number(e.target.value) || 0)}
                />
              </div>
              <div className="grid gap-2">
                <Label htmlFor="termMonths">Vade (ay) *</Label>
                <Input
                  id="termMonths"
                  name="termMonths"
                  type="number"
                  min="1"
                  max="480"
                  required
                  value={term}
                  onChange={(e) => setTerm(Number(e.target.value) || 0)}
                />
              </div>
            </div>

            <div className="grid gap-4 md:grid-cols-2">
              <div className="grid gap-2">
                <Label htmlFor="startDate">Başlangıç *</Label>
                <Input
                  id="startDate"
                  name="startDate"
                  type="date"
                  defaultValue={today}
                  required
                />
              </div>
              <div className="grid gap-2">
                <Label htmlFor="paymentDay">Ödeme günü (1-28)</Label>
                <Input
                  id="paymentDay"
                  name="paymentDay"
                  type="number"
                  min="1"
                  max="28"
                  defaultValue={1}
                />
              </div>
            </div>

            <div className="bg-muted/40 rounded-md border p-3 text-sm">
              <div className="flex items-center justify-between">
                <span className="text-muted-foreground">Aylık taksit</span>
                <span className="font-medium tabular-nums">{formatTRY(monthly)}</span>
              </div>
              <div className="flex items-center justify-between">
                <span className="text-muted-foreground">Toplam ödeme</span>
                <span className="font-medium tabular-nums">{formatTRY(total)}</span>
              </div>
              <div className="flex items-center justify-between">
                <span className="text-muted-foreground">Toplam faiz</span>
                <span className="tabular-nums">{formatTRY(Math.max(0, total - principal))}</span>
              </div>
            </div>

            <div className="grid gap-2">
              <Label htmlFor="notes">Notlar</Label>
              <Textarea id="notes" name="notes" rows={3} placeholder="Sözleşme no, kefiller, vb." />
            </div>
          </div>

          <SheetFooter className="border-t bg-muted/30 px-6 py-4">
            <div className="flex w-full justify-end gap-2">
              <Button type="button" variant="outline" onClick={() => onOpenChange(false)} disabled={isPending}>
                Vazgeç
              </Button>
              <Button type="submit" disabled={isPending}>
                {isPending ? (
                  <>
                    <Loader2 className="size-4 animate-spin" />
                    Oluşturuluyor...
                  </>
                ) : (
                  <>
                    <Save className="size-4" />
                    Krediyi kaydet
                  </>
                )}
              </Button>
            </div>
          </SheetFooter>
        </form>
      </SheetContent>
    </Sheet>
  );
}