"use client";

import { useEffect, useState } from "react";
import Link from "next/link";
import { AppShell } from "@/components/app-shell";
import { Input } from "@/components/ui/input";
import {
  useMissingPrecedents,
  type MissingPrecedentStatus,
} from "@/lib/api/missing-precedents";
import { MissingPrecedentsTable } from "@/components/missing-precedents/missing-precedents-table";

/**
 * Missing-precedents page (TaskMaster #35).
 *
 * Surfaces citations that party briefs invoke but which aren't yet in the
 * precedent_library. A status filter (chips) narrows the table; each row uses
 * the same table component. Drawer (sheet) opens on row click with metadata +
 * upload form that routes to internal_decision_upload (ערר/בל"מ citations) or
 * precedent_library_upload (court rulings).
 */

type StatusFilter = MissingPrecedentStatus | "all";

const STATUS_CHIPS: { value: StatusFilter; label: string }[] = [
  { value: "open", label: "פתוח" },
  { value: "uploaded", label: "הועלה" },
  { value: "closed", label: "נסגר" },
  { value: "irrelevant", label: "לא-רלוונטי" },
  { value: "all", label: "הכל" },
];

export default function MissingPrecedentsPage() {
  const [caseNumber, setCaseNumber] = useState("");
  const [legalTopic, setLegalTopic] = useState("");
  const [filter, setFilter] = useState<StatusFilter>("open");

  /* Debounce the filters so the table fires one query after the user stops
   * typing — not one per keystroke. Each intermediate value used to
   * round-trip to the API (and a non-existent case number errored mid-typing). */
  const [caseNumberQ, setCaseNumberQ] = useState("");
  const [legalTopicQ, setLegalTopicQ] = useState("");
  useEffect(() => {
    const t = setTimeout(() => setCaseNumberQ(caseNumber.trim()), 350);
    return () => clearTimeout(t);
  }, [caseNumber]);
  useEffect(() => {
    const t = setTimeout(() => setLegalTopicQ(legalTopic.trim()), 350);
    return () => clearTimeout(t);
  }, [legalTopic]);

  const counts = useMissingPrecedents({ limit: 1 });
  const byStatus = counts.data?.by_status ?? {};

  return (
    <AppShell>
      <section className="space-y-6">
        <header className="space-y-3">
          <nav className="text-[0.78rem] text-ink-muted">
            <Link href="/" className="hover:text-gold-deep">בית</Link>
            <span aria-hidden> · </span>
            <span className="text-navy">פסיקה חסרה בקורפוס</span>
          </nav>

          {/* title + inline open-count pill (mockup 09 `.open-count`) */}
          <div className="flex items-baseline gap-3.5 flex-wrap">
            <h1 className="text-navy mb-0">פסיקה חסרה בקורפוס</h1>
            {byStatus.open ? (
              <span className="inline-flex items-baseline gap-1.5 rounded-lg border border-rule bg-warn-bg px-3.5 py-1">
                <span className="text-lg font-bold text-warn tabular-nums leading-none">
                  {byStatus.open}
                </span>
                <span className="text-[0.8rem] text-ink-soft">פתוחים</span>
              </span>
            ) : null}
          </div>
          <p className="text-ink-muted text-sm max-w-3xl leading-relaxed">
            פסיקה שצוטטה בכתבי-הטענות אך אינה קיימת בקורפוס. השלמתה מאפשרת
            אימות-הלכה ועיגון-מקור (INV-AH). סוכן המחקר רושם פערים אוטומטית;
            היו&quot;ר סוגר אותם על־ידי העלאת המסמך — ניתוב אוטומטי בין הקורפוס
            הסמכותי (פסקי דין) להחלטות ועדות ערר.
          </p>
        </header>

        <div className="h-[2px] bg-gradient-to-l from-transparent via-gold to-transparent" />

        {/* shared filters */}
        <div className="flex items-end gap-3 flex-wrap">
          <div className="flex-1 min-w-[200px]">
            <label className="block text-[0.78rem] text-ink-muted mb-1.5">תיק (מספר ערר)</label>
            <Input
              value={caseNumber}
              onChange={(e) => setCaseNumber(e.target.value)}
              placeholder="1017-03-26"
              dir="rtl"
            />
          </div>
          <div className="flex-1 min-w-[200px]">
            <label className="block text-[0.78rem] text-ink-muted mb-1.5">נושא משפטי</label>
            <Input
              value={legalTopic}
              onChange={(e) => setLegalTopic(e.target.value)}
              placeholder="זכות עמידה"
              dir="rtl"
            />
          </div>
        </div>

        {/* status filter chips (mockup 09 `.filters`) — active = navy filled */}
        <div className="flex items-center gap-2 flex-wrap">
          {STATUS_CHIPS.map((c) => {
            const active = filter === c.value;
            const count =
              c.value === "all"
                ? undefined
                : (byStatus[c.value as MissingPrecedentStatus] ?? 0);
            return (
              <button
                key={c.value}
                type="button"
                onClick={() => setFilter(c.value)}
                aria-pressed={active}
                className={`rounded-full border px-4 py-1.5 text-[0.82rem] transition-colors ${
                  active
                    ? "bg-navy text-white border-navy font-semibold"
                    : "bg-surface text-ink-soft border-rule font-medium hover:bg-rule-soft/50"
                }`}
              >
                {c.label}
                {count ? (
                  <span className="ms-1.5 tabular-nums opacity-80">({count})</span>
                ) : null}
              </button>
            );
          })}
        </div>

        <MissingPrecedentsTable
          status={filter === "all" ? "" : filter}
          caseNumber={caseNumberQ || undefined}
          legalTopic={legalTopicQ || undefined}
        />

        {/* lifecycle note (mockup 09 `.lifecycle`) */}
        <div className="rounded-lg border border-rule bg-parchment px-5 py-3.5 text-[0.82rem] text-ink-muted leading-7">
          <b className="text-ink-soft">מחזור-חיים:</b>{" "}
          <LifecycleChip tone="open">פתוח</LifecycleChip> →{" "}
          <LifecycleChip tone="up">הועלה</LifecycleChip> →{" "}
          <LifecycleChip tone="closed">נסגר</LifecycleChip>. פריט נפתח אוטומטית
          בעת חילוץ ציטוט שאין לו תקדים בקורפוס; בהעלאת פסק-הדין הוא מקושר לרשומת
          הפסיקה דרך{" "}
          <code className="rounded border border-rule bg-surface px-1.5 py-0.5 text-[0.75rem] text-gold-deep" dir="ltr">
            linked_case_law_id
          </code>{" "}
          ונסגר. פריט שאינו רלוונטי מסומן{" "}
          <LifecycleChip tone="na">לא-רלוונטי</LifecycleChip> מבלי שתידרש העלאה.
        </div>
      </section>
    </AppShell>
  );
}

type LifecycleTone = "open" | "up" | "closed" | "na";

function LifecycleChip({
  tone,
  children,
}: {
  tone: LifecycleTone;
  children: React.ReactNode;
}) {
  const cls: Record<LifecycleTone, string> = {
    open: "bg-warn-bg text-warn",
    up: "bg-info-bg text-info",
    closed: "bg-success-bg text-success",
    na: "bg-rule-soft text-ink-muted",
  };
  return (
    <span className={`inline-block rounded-full px-2.5 py-0.5 text-[0.72rem] font-semibold ${cls[tone]}`}>
      {children}
    </span>
  );
}
