"use client";

import Link from "next/link";
import { useParams, useRouter } from "next/navigation";
import { useCallback, useEffect, useMemo, useState } from "react";

import { api } from "@/lib/api/client";
import type { components } from "@/lib/api/schema";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";

type Person = components["schemas"]["PersonRead"];
type Event = components["schemas"]["EventRead"];
type Relationship = components["schemas"]["RelationshipRead"];
type Qualifier = components["schemas"]["ParentChildQualifier"];
type RelCreate = components["schemas"]["RelationshipCreate"];
type Source = components["schemas"]["SourceRead"];
type Citation = components["schemas"]["CitationRead"];
type CitationCreate = components["schemas"]["CitationCreate"];

const fieldCls = "h-9 rounded-md border border-[var(--border)] bg-[var(--surface)] px-2 text-sm";
const QUALIFIERS: Qualifier[] = ["biological", "adoptive", "step", "foster", "donor", "guardian"];

export default function PersonDetailPage() {
  const router = useRouter();
  const params = useParams<{ id: string; personId: string }>();
  const treeId = params.id;
  const personId = params.personId;

  const [person, setPerson] = useState<Person | null>(null);
  const [people, setPeople] = useState<Person[]>([]);
  const [events, setEvents] = useState<Event[]>([]);
  const [rels, setRels] = useState<Relationship[]>([]);
  const [sources, setSources] = useState<Source[]>([]);
  const [citations, setCitations] = useState<Citation[]>([]);
  const [ready, setReady] = useState(false);

  const [evType, setEvType] = useState("birth");
  const [evDate, setEvDate] = useState("");

  const [relKind, setRelKind] = useState<"parent" | "child" | "partner" | "sibling">("parent");
  const [relOther, setRelOther] = useState("");
  const [relQual, setRelQual] = useState<Qualifier>("biological");

  // Inline citation form: which fact is being cited ("p" = person, `e:<id>`).
  const [citeFor, setCiteFor] = useState<string | null>(null);
  const [citeSource, setCiteSource] = useState("");
  const [citePage, setCitePage] = useState("");

  const load = useCallback(async () => {
    const p = await api.GET("/api/v1/trees/{tree_id}/persons/{person_id}", {
      params: { path: { tree_id: treeId, person_id: personId } },
    });
    if (p.response.status === 401) {
      router.push("/login");
      return;
    }
    setPerson(p.data ?? null);
    const [all, ev, rl, src, cit] = await Promise.all([
      api.GET("/api/v1/trees/{tree_id}/persons", { params: { path: { tree_id: treeId } } }),
      api.GET("/api/v1/trees/{tree_id}/persons/{person_id}/events", {
        params: { path: { tree_id: treeId, person_id: personId } },
      }),
      api.GET("/api/v1/trees/{tree_id}/persons/{person_id}/relationships", {
        params: { path: { tree_id: treeId, person_id: personId } },
      }),
      api.GET("/api/v1/trees/{tree_id}/sources", { params: { path: { tree_id: treeId } } }),
      api.GET("/api/v1/trees/{tree_id}/citations", { params: { path: { tree_id: treeId } } }),
    ]);
    setPeople(all.data ?? []);
    setEvents(ev.data ?? []);
    setRels(rl.data ?? []);
    setSources(src.data ?? []);
    setCitations(cit.data ?? []);
    setReady(true);
  }, [router, treeId, personId]);

  useEffect(() => {
    load();
  }, [load]);

  const nameOf = useMemo(() => {
    const m = new Map(people.map((p) => [p.id, p.primary_name ?? "Unnamed"]));
    return (id: string) => m.get(id) ?? "Unknown";
  }, [people]);
  const sourceName = useMemo(() => {
    const m = new Map(sources.map((s) => [s.id, s.title]));
    return (id: string) => m.get(id) ?? "source";
  }, [sources]);

  const others = people.filter((p) => p.id !== personId);
  const parents = rels.filter((r) => r.type === "parent_child" && r.person_to_id === personId);
  const children = rels.filter((r) => r.type === "parent_child" && r.person_from_id === personId);
  const partners = rels.filter((r) => r.type === "partnership");
  const siblings = rels.filter((r) => r.type === "sibling");
  const eventCites = (id: string) => citations.filter((c) => c.event_id === id);
  const personCites = citations.filter((c) => c.person_id === personId);

  async function addEvent(e: React.FormEvent) {
    e.preventDefault();
    if (!evType.trim()) return;
    const { error } = await api.POST("/api/v1/trees/{tree_id}/events", {
      params: { path: { tree_id: treeId } },
      body: { event_type: evType, person_id: personId, date_value: evDate || null },
    });
    if (!error) {
      setEvDate("");
      load();
    }
  }
  async function removeEvent(id: string) {
    await api.DELETE("/api/v1/trees/{tree_id}/events/{event_id}", {
      params: { path: { tree_id: treeId, event_id: id } },
    });
    load();
  }

  async function addRel(e: React.FormEvent) {
    e.preventDefault();
    if (!relOther) return;
    let body: RelCreate;
    if (relKind === "parent") {
      body = { type: "parent_child", person_from_id: relOther, person_to_id: personId, qualifier: relQual };
    } else if (relKind === "child") {
      body = { type: "parent_child", person_from_id: personId, person_to_id: relOther, qualifier: relQual };
    } else if (relKind === "partner") {
      body = { type: "partnership", person_from_id: personId, person_to_id: relOther };
    } else {
      body = { type: "sibling", person_from_id: personId, person_to_id: relOther };
    }
    const { error } = await api.POST("/api/v1/trees/{tree_id}/relationships", {
      params: { path: { tree_id: treeId } },
      body,
    });
    if (!error) {
      setRelOther("");
      load();
    }
  }
  async function removeRel(id: string) {
    await api.DELETE("/api/v1/trees/{tree_id}/relationships/{relationship_id}", {
      params: { path: { tree_id: treeId, relationship_id: id } },
    });
    load();
  }

  async function addCitation(target: Partial<CitationCreate>) {
    if (!citeSource) return;
    const body: CitationCreate = { source_id: citeSource, page: citePage || null, ...target };
    const { error } = await api.POST("/api/v1/trees/{tree_id}/citations", {
      params: { path: { tree_id: treeId } },
      body,
    });
    if (!error) {
      setCiteFor(null);
      setCiteSource("");
      setCitePage("");
      load();
    }
  }
  async function removeCitation(id: string) {
    await api.DELETE("/api/v1/trees/{tree_id}/citations/{citation_id}", {
      params: { path: { tree_id: treeId, citation_id: id } },
    });
    load();
  }

  if (!ready) return <p className="text-[var(--muted)]">Loading…</p>;
  if (!person) return <p className="text-[var(--muted)]">Not found.</p>;

  // Inline "cite" control: a badge with count, a toggle, and the picker form.
  function citeControl(key: string, target: Partial<CitationCreate>, cites: Citation[]) {
    return (
      <span className="inline-flex items-center gap-2">
        {cites.length > 0 && (
          <span
            className="rounded bg-bronze/15 px-1.5 py-0.5 text-xs text-bronze"
            title={cites.map((c) => sourceName(c.source_id)).join(", ")}
          >
            ✓ {cites.length} sourced
          </span>
        )}
        {citeFor === key ? (
          <form
            onSubmit={(e) => {
              e.preventDefault();
              addCitation(target);
            }}
            className="inline-flex items-center gap-1"
          >
            <select
              className={fieldCls}
              value={citeSource}
              onChange={(e) => setCiteSource(e.target.value)}
            >
              <option value="">— source —</option>
              {sources.map((s) => (
                <option key={s.id} value={s.id}>
                  {s.title}
                </option>
              ))}
            </select>
            <input
              className={`${fieldCls} w-24`}
              placeholder="page"
              value={citePage}
              onChange={(e) => setCitePage(e.target.value)}
            />
            <Button type="submit" size="sm">
              cite
            </Button>
            <button
              type="button"
              onClick={() => setCiteFor(null)}
              className="text-xs text-[var(--muted)]"
            >
              cancel
            </button>
          </form>
        ) : sources.length === 0 ? (
          <Link href={`/trees/${treeId}/sources`} className="text-xs text-[var(--muted)] hover:underline">
            + add a source first
          </Link>
        ) : (
          <button
            type="button"
            onClick={() => {
              setCiteFor(key);
              setCiteSource("");
              setCitePage("");
            }}
            className="text-xs text-bronze hover:underline"
          >
            + cite
          </button>
        )}
      </span>
    );
  }

  const relGroup = (label: string, items: Relationship[], otherId: (r: Relationship) => string) =>
    items.length > 0 && (
      <div>
        <h3 className="text-sm font-semibold text-bronze">{label}</h3>
        <ul className="mt-1 space-y-1">
          {items.map((r) => (
            <li key={r.id} className="flex items-center justify-between text-sm">
              <Link href={`/trees/${treeId}/persons/${otherId(r)}`} className="hover:underline">
                {nameOf(otherId(r))}
                {r.qualifier ? <span className="text-[var(--muted)]"> · {r.qualifier}</span> : null}
              </Link>
              <button
                onClick={() => removeRel(r.id)}
                className="text-[var(--muted)] hover:text-bronze"
                aria-label="Remove"
              >
                ×
              </button>
            </li>
          ))}
        </ul>
      </div>
    );

  return (
    <div className="space-y-6">
      <Link href={`/trees/${treeId}`} className="text-sm text-[var(--muted)] hover:underline">
        ← Back to tree
      </Link>

      <div className="flex flex-wrap items-center justify-between gap-2">
        <h1 className="text-3xl font-semibold">{person.primary_name ?? "Unnamed person"}</h1>
        {citeControl("p", { person_id: personId }, personCites)}
      </div>

      <Card>
        <CardHeader>
          <CardTitle className="text-base">Life events</CardTitle>
        </CardHeader>
        <CardContent className="space-y-4">
          {events.length === 0 ? (
            <p className="text-sm text-[var(--muted)]">No events yet.</p>
          ) : (
            <ul className="space-y-2">
              {events.map((ev) => (
                <li key={ev.id} className="flex flex-wrap items-center justify-between gap-2 text-sm">
                  <span>
                    <span className="font-medium capitalize">{ev.event_type}</span>
                    {ev.date_value ? (
                      <span className="text-[var(--muted)]"> — {ev.date_value}</span>
                    ) : null}
                  </span>
                  <span className="flex items-center gap-3">
                    {citeControl(`e:${ev.id}`, { event_id: ev.id }, eventCites(ev.id))}
                    <button
                      onClick={() => removeEvent(ev.id)}
                      className="text-[var(--muted)] hover:text-bronze"
                      aria-label="Remove"
                    >
                      ×
                    </button>
                  </span>
                </li>
              ))}
            </ul>
          )}
          <form onSubmit={addEvent} className="flex flex-wrap gap-2">
            <Input className="w-36" placeholder="Event type" value={evType} onChange={(e) => setEvType(e.target.value)} />
            <Input className="w-40" placeholder="Date (e.g. ABT 1850)" value={evDate} onChange={(e) => setEvDate(e.target.value)} />
            <Button type="submit">Add event</Button>
          </form>
        </CardContent>
      </Card>

      <Card>
        <CardHeader>
          <CardTitle className="text-base">Relationships</CardTitle>
        </CardHeader>
        <CardContent className="space-y-4">
          {rels.length === 0 ? (
            <p className="text-sm text-[var(--muted)]">No relationships yet.</p>
          ) : (
            <div className="grid gap-4 sm:grid-cols-2">
              {relGroup("Parents", parents, (r) => r.person_from_id)}
              {relGroup("Children", children, (r) => r.person_to_id)}
              {relGroup("Partners", partners, (r) =>
                r.person_from_id === personId ? r.person_to_id : r.person_from_id,
              )}
              {relGroup("Siblings", siblings, (r) =>
                r.person_from_id === personId ? r.person_to_id : r.person_from_id,
              )}
            </div>
          )}

          {others.length === 0 ? (
            <p className="text-sm text-[var(--muted)]">Add more people to the tree to link them.</p>
          ) : (
            <form onSubmit={addRel} className="flex flex-wrap items-center gap-2">
              <span className="text-sm text-[var(--muted)]">Add</span>
              <select className={fieldCls} value={relKind} onChange={(e) => setRelKind(e.target.value as typeof relKind)}>
                <option value="parent">parent</option>
                <option value="child">child</option>
                <option value="partner">partner</option>
                <option value="sibling">sibling</option>
              </select>
              <select className={fieldCls} value={relOther} onChange={(e) => setRelOther(e.target.value)}>
                <option value="">— person —</option>
                {others.map((p) => (
                  <option key={p.id} value={p.id}>
                    {p.primary_name ?? "Unnamed"}
                  </option>
                ))}
              </select>
              {(relKind === "parent" || relKind === "child") && (
                <select className={fieldCls} value={relQual} onChange={(e) => setRelQual(e.target.value as Qualifier)}>
                  {QUALIFIERS.map((q) => (
                    <option key={q} value={q}>
                      {q}
                    </option>
                  ))}
                </select>
              )}
              <Button type="submit">Link</Button>
            </form>
          )}
        </CardContent>
      </Card>
    </div>
  );
}
