import { useEffect, useMemo, useState } from "react";
import { toast } from "sonner";
import type { Attachment, Milestone, Quote } from "../../lib/types";
import { api, nextDashedId } from "../../lib/api";
import { useMaterials, useProjects, useQuotes, useUpdateQuote, useSuppliers } from "../../hooks";
import {
  activeItems,
  formatMaterialTitle,
  itemTermsheetIds,
  materialById,
  supplierById,
} from "../../lib/quoteUtils";
import { faNum, fmtNum } from "../../lib/formatters";
import { groupCommas } from "../../lib/numutil";
import { Button } from "../../components/ui/button";
import {
  Dialog,
  DialogContent,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "../../components/ui/dialog";
import { MilestoneRow } from "../../components/MilestoneRow";
import { FileList } from "../../components/FileList";
import { JalaliDatePicker } from "../../components/JalaliDatePicker";

interface CardDraft {
  domId: string;
  isNew: boolean;
  milestones: Milestone[];
  label: string | null; // null = پیش‌فرض «گزینه N»
}

export interface AcceptModalProps {
  quoteId: string | null;
  onClose: () => void;
}

export function AcceptModal({ quoteId, onClose }: AcceptModalProps) {
  const quotes = useQuotes();
  const suppliers = useSuppliers();
  const materials = useMaterials();
  const projects = useProjects();
  const updateQuote = useUpdateQuote();

  const q = useMemo(() => quotes.find((x) => x.id === quoteId) || null, [quotes, quoteId]);

  const [cards, setCards] = useState<CardDraft[]>([]);
  const [invoices, setInvoices] = useState<Attachment[]>([]);
  const [proformas, setProformas] = useState<Attachment[]>([]);
  const [removedItems, setRemovedItems] = useState<Set<string>>(new Set());
  const [assignments, setAssignments] = useState<Record<string, string>>({});
  const [itemProjectsSel, setItemProjectsSel] = useState<Record<string, string>>({});
  const [acceptDate, setAcceptDate] = useState<string | null>(() => new Date().toISOString());
  const [ready, setReady] = useState(false);

  useMemo(() => {
    if (!q) return;
    const offered = q.termsheets.filter((t) => t.status === "offered");
    setCards(
      offered.map((t) => ({ domId: t.id, isNew: false, milestones: JSON.parse(JSON.stringify(t.milestones)), label: t.label })),
    );
    const rem = new Set<string>();
    q.line_items.forEach((li) => {
      if (li.rejected) rem.add(li.id);
    });
    setRemovedItems(rem);
    setAssignments({});
    const projSel: Record<string, string> = {};
    q.line_items.forEach((li) => {
      const names = (li.projects || []).map((p) => p.name).filter(Boolean);
      projSel[li.id] = li.target_project?.name
        ? li.target_project.name
        : names.length
          ? names[0]
          : q.projects && q.projects.length
            ? q.projects[0]
            : q.project || "";
    });
    setItemProjectsSel(projSel);
    setReady(true);
  }, [q]);

  useEffect(() => {
    if (!quoteId) return;
    let alive = true;
    void api.files
      .list(quoteId, "invoice")
      .then((list) => alive && setInvoices(list))
      .catch(() => alive && setInvoices([]));
    void api.files
      .list(quoteId, "proforma")
      .then((list) => alive && setProformas(list))
      .catch(() => alive && setProformas([]));
    return () => {
      alive = false;
    };
  }, [quoteId]);

  if (!q || !ready) return null;

  const sup = supplierById(suppliers, q.supplier_id);
  const allItems = q.line_items || [];
  const active = activeItems(q);

  const projectOptions = (() => {
    const set = new Set<string>();
    projects.forEach((p) => p.name && set.add(p.name));
    (q.projects || []).forEach((n) => set.add(n));
    if (q.project) set.add(q.project);
    allItems.forEach((li) => (li.projects || []).forEach((p) => p.name && set.add(p.name)));
    return [...set].sort((a, b) => a.localeCompare(b, "fa"));
  })();

  const cardLabel = (c: CardDraft, idx: number) => c.label || `گزینه ${faNum(idx + 1)}`;

  const updateCard = (domId: string, patch: Partial<CardDraft>) => {
    setCards((cs) => cs.map((c) => (c.domId === domId ? { ...c, ...patch } : c)));
  };

  const addNewCard = () => {
    setCards((cs) => [...cs, { domId: "new-ts-" + Date.now(), isNew: true, milestones: [{ when_iso: null, amount: null }], label: null }]);
  };

  const removeCard = (domId: string) => {
    setCards((cs) => cs.filter((c) => c.domId !== domId));
    setAssignments((a) => {
      const next: Record<string, string> = {};
      Object.entries(a).forEach(([liId, dom]) => {
        if (dom !== domId) next[liId] = dom;
      });
      return next;
    });
  };

  const assign = (liId: string, domId: string) => {
    setAssignments((a) => ({ ...a, [liId]: domId }));
  };

  const confirm = () => {
    if (!q) return;

    const next: Quote = JSON.parse(JSON.stringify(q));

    const cardMeta = new Map<string, { milestones: Milestone[]; label: string; existing: Quote["termsheets"][number] | undefined }>();
    cards.forEach((c, idx) => {
      const milestones = c.milestones.filter((m) => m.when_iso || m.amount != null);
      if (!milestones.length) return;
      const existing = next.termsheets.find((t) => t.id === c.domId);
      cardMeta.set(c.domId, {
        milestones,
        label: c.label || `گزینه ${faNum(idx + 1)}`,
        existing,
      });
    });

    if (!cardMeta.size) {
      toast.error("حداقل یک شرایط پرداخت با حداقل یک مرحله پرداخت لازم است.");
      return;
    }

    next.line_items.forEach((li) => {
      if (removedItems.has(li.id)) li.rejected = true;
    });
    const active = activeItems(next);
    if (!active.length) {
      toast.error("همه‌ی قلم‌ها رد شده‌اند؛ حداقل یک قلم لازم است.");
      return;
    }

    const fallbackDom = [...cardMeta.keys()][0];
    const chosenDomIds = new Set<string>();
    active.forEach((li) => {
      const dom = assignments[li.id] || fallbackDom;
      if (dom && cardMeta.has(dom)) chosenDomIds.add(dom);
    });

    const domToFinal: Record<string, string> = {};
    chosenDomIds.forEach((dom) => {
      const meta = cardMeta.get(dom)!;
      if (meta.existing) {
        meta.existing.milestones = meta.milestones;
        meta.existing.status = "accepted";
        domToFinal[dom] = dom;
      } else {
        const newId = nextDashedId("ts", next.termsheets);
        next.termsheets.push({ id: newId, label: meta.label, milestones: meta.milestones, status: "accepted" });
        domToFinal[dom] = newId;
      }
    });

    active.forEach((li) => {
      const dom = assignments[li.id] || fallbackDom;
      const finalId = domToFinal[dom];
      const current = itemTermsheetIds(li).filter((tid) => next.termsheets.some((t) => t.id === tid));
      if (finalId && !current.includes(finalId)) current.push(finalId);
      li.termsheet_ids = current.length ? current : finalId ? [finalId] : current;
      li.accepted_ts_id = finalId || null;
    });

    const usedIds = new Set<string>();
    active.forEach((li) => {
      if (li.accepted_ts_id) usedIds.add(li.accepted_ts_id);
    });
    next.termsheets.forEach((t) => {
      if (t.status === "accepted" && !usedIds.has(t.id)) t.status = "offered";
    });

    // پروژه‌ی هر قلم (تکی هدف خرید) — فقط target_project تنظیم می‌شود؛
    // li.projects و next.projects دست‌نخورده باقی می‌مانند تا پروژه‌های کاندیدای اولیه حفظ شوند
    next.line_items.forEach((li) => {
      if (li.rejected) return;
      const name = itemProjectsSel[li.id];
      if (name === undefined) return;
      li.target_project = name ? { id: "", name } : null;
    });

    const now = new Date().toISOString();
    next.accepted_date = acceptDate || now;
    next.status = "accepted";
    next.events.push({ type: "accepted", occurred_at: now });
    next.invoices = invoices;
    next.proformas = proformas;

    void updateQuote.mutateAsync({ id: q.id, patch: next });
    setReady(false);
    onClose();
  };

  return (
    <Dialog open={!!quoteId} onOpenChange={(o) => !o && onClose()}>
      <DialogContent className="max-w-3xl p-0 gap-0 overflow-hidden bg-slate-50 border-none shadow-2xl rounded-xl">
        <div className="flex flex-col max-h-[85vh] w-full">
          
          {/* هدر ثابت و هم‌تراز */}
          <div className="px-6 py-4 bg-white border-b border-line shrink-0 z-10 text-right">
            <DialogHeader className="p-0 text-right">
              <div className="flex items-center justify-between gap-3">
                <DialogTitle className="text-right text-lg font-bold text-slate-800">
                  پذیرش پیشنهاد — {sup.name}
                </DialogTitle>
                <span className="font-mono text-xs font-bold text-slate-700 bg-slate-100 px-2.5 py-1 rounded-lg border border-line shrink-0 select-all">
                  کد: {q.id.startsWith("PR-") ? q.id : `PR-${q.id}`}
                </span>
              </div>
            </DialogHeader>
            <p className="text-[13px] text-muted mt-1 text-right">
              شرایط پرداخت را ویرایش کنید. سپس هر قلم را به بخش و پروژه دلخواه تخصیص دهید.
            </p>
          </div>

          {/* بدنه اسکرول‌پذیر */}
          <div className="flex-1 overflow-y-auto p-4 md:p-6 space-y-5">
            
            {/* بخش ۱: تنظیم شرایط پرداخت */}
            <section className="bg-white rounded-xl shadow-sm border border-line p-4 md:p-5">
              <h3 className="mb-4 text-[14px] font-bold text-slate-800">۱. تنظیم شرایط پرداخت</h3>
              <div className="flex flex-col gap-4">
                {cards.map((c, idx) => (
                  <div key={c.domId} className="modal-variant bg-slate-50/50 rounded-lg border border-line p-3">
                    <div className="modal-variant-head mb-2 flex items-center justify-between">
                      <span className="variant-num font-semibold text-primary">{cardLabel(c, idx)}</span>
                      <button type="button" className="text-red-500 hover:text-red-700 hover:bg-red-50 rounded-full w-6 h-6 flex items-center justify-center transition-colors" title="حذف" onClick={() => removeCard(c.domId)}>
                        ×
                      </button>
                    </div>
                    <div className="flex flex-col gap-2">
                      {c.milestones.map((m, i) => (
                        <MilestoneRow
                          key={i}
                          milestone={m}
                          onChange={(nextM) => {
                            const ms = [...c.milestones];
                            ms[i] = nextM;
                            updateCard(c.domId, { milestones: ms });
                          }}
                          onRemove={() => updateCard(c.domId, { milestones: c.milestones.filter((_, j) => j !== i) })}
                        />
                      ))}
                    </div>
                    <Button variant="ghost" size="sm" className="mt-3 text-xs text-primary bg-primary/5 hover:bg-primary/10" onClick={() => updateCard(c.domId, { milestones: [...c.milestones, { when_iso: null, amount: null }] })}>
                      ＋ مرحله پرداخت جدید
                    </Button>
                  </div>
                ))}
              </div>
              <Button variant="line" size="sm" className="mt-4 border-dashed border-primary/50 text-primary hover:bg-primary/5" onClick={addNewCard}>
                ＋ افزودن شرایط پرداخت جدید
              </Button>
            </section>

            {/* بخش ۲: تخصیص اقلام */}
            <section className="bg-white rounded-xl shadow-sm border border-line p-4 md:p-5">
              <h3 className="mb-1 text-[14px] font-bold text-slate-800">۲. تخصیص اقلام به شرایط پرداخت</h3>
              <div className="mb-4 text-[12px] text-muted">
                قلمی که می‌خرید را تیک بزنید؛ قلمی که نمی‌خرید را بدون تیک رها کنید تا از معامله حذف شود.
              </div>
              <div className="flex flex-col gap-2">
                {allItems.map((li) => {
                  const removed = removedItems.has(li.id);
                  const m = materialById(materials, li.material_id);
                  return (
                    <div 
                      key={li.id} 
                      className={`accept-item-assign-row flex flex-wrap sm:flex-nowrap items-center gap-3 p-3 rounded-lg border border-line transition-all ${removed ? "bg-slate-50 opacity-60 grayscale" : "bg-white hover:border-primary/30"}`}
                    >
                      <input
                        type="checkbox"
                        className="accent-primary w-4 h-4 rounded cursor-pointer shrink-0"
                        checked={!removed}
                        title="تیک = در معامله می‌ماند"
                        onChange={(e) => {
                          const next = new Set(removedItems);
                          if (e.target.checked) next.delete(li.id);
                          else next.add(li.id);
                          setRemovedItems(next);
                        }}
                      />
                      <div className="flex-1 min-w-[120px]">
                        <div className="text-[13.5px] font-medium text-slate-800">
                          {formatMaterialTitle(m)}
                        </div>
                        <div className="text-[12px] text-muted mt-0.5">
                          {fmtNum(li.quantity)} {li.unit} × {groupCommas(li.unit_price, true)}
                        </div>
                      </div>
                      
                      <select
                        className={`min-w-[160px] h-9 rounded-md border border-line bg-panel px-2.5 py-1.5 font-inherit text-[12px] outline-none transition-all ${!removed ? 'focus:border-primary focus:ring-1 focus:ring-primary' : 'cursor-not-allowed'}`}
                        value={assignments[li.id] || cards[0]?.domId || ""}
                        onChange={(e) => assign(li.id, e.target.value)}
                        disabled={removed}
                      >
                        {cards.map((c, idx) => (
                          <option key={c.domId} value={c.domId}>
                            {cardLabel(c, idx)}
                          </option>
                        ))}
                      </select>
                    </div>
                  );
                })}
                {active.length === 0 && (
                  <div className="mt-2 p-3 bg-red-50 text-red-600 rounded-md text-[13px] font-medium flex items-center gap-2">
                    <span>⚠️</span> همه‌ی قلم‌ها رد شده‌اند — حداقل یک قلم را تیک بزنید.
                  </div>
                )}
              </div>
            </section>

            {/* بخش ۳: تخصیص اقلام به پروژه */}
            <section className="bg-white rounded-xl shadow-sm border border-line p-4 md:p-5">
              <h3 className="mb-1 text-[14px] font-bold text-slate-800">۳. تخصیص اقلام به پروژه‌ها</h3>
              <div className="mb-4 text-[12px] text-muted">
                برای هر متریال خریداری شده، می‌توانید پروژه مربوط به آن را مشخص کنید.
              </div>
              <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
                {allItems
                  .filter((li) => !removedItems.has(li.id))
                  .map((li) => {
                    const m = materialById(materials, li.material_id);
                    return (
                      <div key={li.id} className="rounded-lg border border-line p-3 flex flex-col justify-between hover:border-primary/30 transition-colors">
                        <div className="mb-3 flex items-center justify-between">
                          <span className="text-[13px] font-semibold text-slate-800 truncate">
                            {formatMaterialTitle(m)}
                          </span>
                          <span className="ms-2 text-[11px] text-muted bg-slate-100 px-2 py-0.5 rounded-full whitespace-nowrap">
                            {fmtNum(li.quantity)} {li.unit}
                          </span>
                        </div>
                        {projectOptions.length ? (
                          <select
                            className="w-full h-9 rounded-md border border-line bg-panel px-2.5 py-1.5 font-inherit text-[12px] outline-none focus:border-primary focus:ring-1 focus:ring-primary transition-all"
                            value={itemProjectsSel[li.id] ?? ""}
                            onChange={(e) =>
                              setItemProjectsSel((s) => ({ ...s, [li.id]: e.target.value }))
                            }
                          >
                            {(itemProjectsSel[li.id] ? [] : [{ name: "" }]).map((_, i) => (
                              <option key={i} value="">
                                انتخاب پروژه...
                              </option>
                            ))}
                            {projectOptions.map((n) => (
                              <option key={n} value={n}>
                                {n}
                              </option>
                            ))}
                          </select>
                        ) : (
                          <div className="text-[12px] text-muted bg-slate-50 p-2 rounded-md text-center">پروژه‌ای در سیستم ثبت نشده است.</div>
                        )}
                      </div>
                    );
                  })}
              </div>
            </section>

            {/* بخش ۴: فاکتورها، پیش‌فاکتورها و تاریخ */}
            <section className="bg-white rounded-xl shadow-sm border border-line p-4 md:p-5 space-y-6">
              <div>
                <h3 className="mb-2 text-[14px] font-bold text-slate-800">فاکتورهای اصلی</h3>
                <FileList
                  files={invoices}
                  onChange={setInvoices}
                  upload={(f) => api.files.upload(q.id, "invoice", f)}
                  onDelete={(a) =>
                    a.id &&
                    void api.files.remove(q.id, "invoice", a.id).catch((err) =>
                      toast.error(err instanceof Error ? err.message : "حذف فاکتور ناموفق بود"),
                    )
                  }
                  onDownload={(a) => api.files.download(q.id, "invoice", a.id!, a.name)}
                  loadPreview={(a) => api.files.previewUrl(q.id, "invoice", a.id!)}
                />
              </div>

              <div className="h-px bg-line w-full"></div>

              <div>
                <h3 className="mb-2 text-[14px] font-bold text-slate-800">پیش‌فاکتورها</h3>
                <FileList
                  files={proformas}
                  onChange={setProformas}
                  upload={(f) => api.files.upload(q.id, "proforma", f)}
                  onDelete={(a) =>
                    a.id &&
                    void api.files.remove(q.id, "proforma", a.id).catch((err) =>
                      toast.error(err instanceof Error ? err.message : "حذف پیش‌فاکتور ناموفق بود"),
                    )
                  }
                  onDownload={(a) => api.files.download(q.id, "proforma", a.id!, a.name)}
                  loadPreview={(a) => api.files.previewUrl(q.id, "proforma", a.id!)}
                  label="افزودن پیش‌فاکتور"
                />
              </div>

              <div className="h-px bg-line w-full"></div>

              <div className="max-w-xs">
                <label className="block mb-2 text-[13px] font-bold text-slate-800">تاریخ و زمان پذیرش</label>
                <JalaliDatePicker value={acceptDate} onChange={setAcceptDate} placeholder="تاریخ و ساعت" withTime />
              </div>
            </section>

          </div>

        {/* فوتر ثابت */}
        <div className="px-6 py-4 bg-white border-t border-line shrink-0 z-10">
          <DialogFooter className="flex w-full gap-3 sm:justify-end">
            <Button variant="slate" onClick={onClose} className="w-full sm:w-auto">
              انصراف
            </Button>
            <Button onClick={confirm} className="w-full sm:w-auto">
              ثبت معامله بسته‌شده
            </Button>
          </DialogFooter>
        </div>

        </div>
      </DialogContent>
    </Dialog>
  );
}