"use client";

import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { generateNames, scoreName, type Idea, type Style } from "@/lib/generate";
import { DEFAULT_TLDS, TLDS, UNVERIFIABLE_TLDS } from "@/lib/tlds";
import { DEFAULT_REGISTRAR, REGISTRARS, registerUrl } from "@/lib/registrars";
import { generateWithAi, loadAiSettings, type AiSettings } from "@/lib/ai";
import { generateWithPlatformAi } from "@/lib/platform-ai";
import { otmSsoUrl } from "@/lib/otm";
import { loadWishlist, saveWishlist, wishlistAsText, WISHLIST_MAX, type SavedName } from "@/lib/wishlist";

type Availability = "available" | "taken" | "unverified-available" | "unknown";

interface DomainCheck {
  domain: string;
  status: Availability;
  method: "rdap" | "dns" | "none";
  detail?: string;
}

/** How many names to put on screen. Each one costs `selectedTlds.length`
 *  registry lookups, so this is the main dial on how hard we lean on the
 *  registries — keep it modest. */
const NAME_COUNT = 24;

/** Domains per availability request. The route caps at 60; staying under it
 *  means results paint in progressively instead of in one late lump. */
const BATCH = 40;

const STYLES: Array<{ id: Style; label: string; note: string }> = [
  { id: "balanced", label: "Balanced", note: "a bit of everything" },
  { id: "real", label: "Real words", note: "northbakery, axlekit" },
  { id: "coined", label: "Coined", note: "novault, tensora" },
  { id: "short", label: "Short", note: "brevity first" },
];

export default function Finder() {
  const [keywords, setKeywords] = useState("");
  const [style, setStyle] = useState<Style>("balanced");
  const [tlds, setTlds] = useState<string[]>(DEFAULT_TLDS);
  const [registrar, setRegistrar] = useState(DEFAULT_REGISTRAR);
  const [ideas, setIdeas] = useState<Idea[]>([]);
  const [checks, setChecks] = useState<Record<string, DomainCheck>>({});
  const [pending, setPending] = useState<Set<string>>(new Set());
  const [seed, setSeed] = useState(1);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [ai, setAi] = useState<AiSettings | null>(null);
  const [useAi, setUseAi] = useState(false);
  // Platform AI: who's signed in with OTM (null = nobody) and whether this
  // deployment has the gateway wired at all. Fetched once on mount.
  const [account, setAccount] = useState<{ email: string; name: string | null } | null>(null);
  const [platformAi, setPlatformAi] = useState(false);
  const [usePlatformAi, setUsePlatformAi] = useState(true);
  const [signinNote, setSigninNote] = useState<string | null>(null);
  // How many names the last run got from AI vs the built-in generator — shown
  // as a one-line summary so it's obvious whether AI actually contributed
  // (issue #3). null until a run completes.
  const [aiCount, setAiCount] = useState<number | null>(null);
  // Hide names whose every checked extension is taken (issue #3). Persisted.
  const [hideTaken, setHideTaken] = useState(false);
  const [saved, setSaved] = useState<SavedName[]>([]);
  const [savedLoaded, setSavedLoaded] = useState(false);
  const [rechecking, setRechecking] = useState(false);
  const [copied, setCopied] = useState(false);

  // Wishlist: read once on mount, written on every change after that. The
  // `savedLoaded` gate stops the first (empty) render from clobbering storage.
  useEffect(() => {
    setSaved(loadWishlist());
    setSavedLoaded(true);
  }, []);
  useEffect(() => {
    if (savedLoaded) saveWishlist(saved);
  }, [saved, savedLoaded]);

  // Keep saved snapshots current: whenever a lookup resolves a domain that's on
  // the shortlist, copy the fresh status in. Cheap, and it means a name saved
  // while still "checking" ends up with a real answer.
  useEffect(() => {
    setSaved((prev) => {
      let changed = false;
      const next = prev.map((e) => {
        let entry = e;
        for (const d of e.domains) {
          const c = checks[d];
          if (!c) continue;
          const old = entry.checks[d];
          if (old && old.status === c.status && old.detail === c.detail) continue;
          entry = { ...entry, checks: { ...entry.checks, [d]: { status: c.status, method: c.method, detail: c.detail } } };
          changed = true;
        }
        return entry;
      });
      return changed ? next : prev;
    });
  }, [checks]);

  const savedNames = useMemo(() => new Set(saved.map((e) => e.name)), [saved]);

  const toggleSaved = useCallback(
    (name: string, domains: string[]) => {
      setSaved((prev) => {
        if (prev.some((e) => e.name === name)) return prev.filter((e) => e.name !== name);
        if (prev.length >= WISHLIST_MAX) return prev;
        const snapshot: SavedName["checks"] = {};
        for (const d of domains) {
          const c = checks[d];
          if (c) snapshot[d] = { status: c.status, method: c.method, detail: c.detail };
        }
        return [{ name, domains, checks: snapshot, savedAt: new Date().toISOString() }, ...prev];
      });
    },
    [checks],
  );

  const removeSaved = (name: string) => setSaved((prev) => prev.filter((e) => e.name !== name));

  /** Re-query every saved domain. Independent of the main run's cancellation —
   *  a shortlist re-check shouldn't die because the visitor hit "Show me more". */
  const recheckSaved = async () => {
    const domains = Array.from(new Set(saved.flatMap((e) => e.domains)));
    if (domains.length === 0) return;
    setRechecking(true);
    setError(null);
    try {
      for (let i = 0; i < domains.length; i += BATCH) {
        const slice = domains.slice(i, i + BATCH);
        const res = await fetch("/api/availability", {
          method: "POST",
          headers: { "content-type": "application/json" },
          body: JSON.stringify({ domains: slice }),
        });
        if (!res.ok) {
          const body = (await res.json().catch(() => ({}))) as { error?: string };
          setError(body.error ?? `Availability lookup failed (${res.status}).`);
          break;
        }
        const body = (await res.json()) as { results: DomainCheck[] };
        const fresh: Record<string, DomainCheck> = {};
        for (const r of body.results) fresh[r.domain] = r;
        setSaved((prev) =>
          prev.map((e) => {
            const nextChecks = { ...e.checks };
            for (const d of e.domains) {
              const c = fresh[d];
              if (c) nextChecks[d] = { status: c.status, method: c.method, detail: c.detail };
            }
            return { ...e, checks: nextChecks };
          }),
        );
      }
    } catch {
      setError("Could not reach the availability service.");
    } finally {
      setRechecking(false);
    }
  };

  const copySaved = async () => {
    try {
      await navigator.clipboard.writeText(wishlistAsText(saved));
      setCopied(true);
      window.setTimeout(() => setCopied(false), 1500);
    } catch {
      setError("Couldn't copy — your browser blocked clipboard access.");
    }
  };

  // The saved key is read once on mount; Settings lives on its own page, so it
  // can't change underneath us mid-session.
  useEffect(() => {
    setAi(loadAiSettings());
    try {
      setHideTaken(window.localStorage.getItem("names.hideTaken") === "1");
    } catch {
      /* private mode */
    }
  }, []);

  const toggleHideTaken = (v: boolean) => {
    setHideTaken(v);
    try {
      window.localStorage.setItem("names.hideTaken", v ? "1" : "0");
    } catch {
      /* private mode */
    }
  };

  useEffect(() => {
    let alive = true;
    fetch("/api/auth/session", { cache: "no-store" })
      .then((r) => (r.ok ? r.json() : null))
      .then((b: { platformAi?: boolean; user?: { email: string; name: string | null } | null } | null) => {
        if (!alive || !b) return;
        setPlatformAi(Boolean(b.platformAi));
        setAccount(b.user ?? null);
      })
      .catch(() => {});
    // The SSO callback bounces failures back here as ?signin=<reason>.
    const reason = new URLSearchParams(window.location.search).get("signin");
    if (reason) {
      setSigninNote(
        reason === "link_already_used"
          ? "That sign-in link was already used — try again."
          : reason === "not_enabled"
            ? "Sign-in isn't enabled on this deployment."
            : "Sign-in didn't complete — try again.",
      );
      window.history.replaceState(null, "", window.location.pathname);
    }
    return () => {
      alive = false;
    };
  }, []);

  const signOut = async () => {
    await fetch("/api/auth/signout", { method: "POST" }).catch(() => {});
    setAccount(null);
  };

  // Abandon in-flight lookups when a new search starts, so a slow batch from
  // the previous query can't paint stale statuses over the new results.
  const runId = useRef(0);

  const parsedKeywords = useMemo(
    () =>
      keywords
        .split(/[,\s]+/)
        .map((k) => k.trim().toLowerCase())
        .filter(Boolean),
    [keywords],
  );

  /** Every domain a set of ideas implies, in display order. */
  const domainsFor = useCallback(
    (list: Idea[], selected: string[]): string[] => {
      const out: string[] = [];
      for (const idea of list) {
        if (idea.hackTld && idea.hackStem) {
          out.push(`${idea.hackStem}.${idea.hackTld}`);
          continue;
        }
        for (const tld of selected) out.push(`${idea.name}.${tld}`);
      }
      return out;
    },
    [],
  );

  const lookup = useCallback(async (domains: string[], myRun: number) => {
    setPending(new Set(domains));

    for (let i = 0; i < domains.length; i += BATCH) {
      if (runId.current !== myRun) return; // superseded by a newer search
      const slice = domains.slice(i, i + BATCH);
      try {
        const res = await fetch("/api/availability", {
          method: "POST",
          headers: { "content-type": "application/json" },
          body: JSON.stringify({ domains: slice }),
        });
        if (runId.current !== myRun) return;

        if (!res.ok) {
          const body = (await res.json().catch(() => ({}))) as { error?: string };
          setError(body.error ?? `Availability lookup failed (${res.status}).`);
          setPending(new Set());
          return;
        }
        const body = (await res.json()) as { results: DomainCheck[] };
        setChecks((prev) => {
          const next = { ...prev };
          for (const r of body.results) next[r.domain] = r;
          return next;
        });
      } catch {
        if (runId.current !== myRun) return;
        setError("Could not reach the availability service.");
        setPending(new Set());
        return;
      }
      setPending((prev) => {
        const next = new Set(prev);
        for (const d of slice) next.delete(d);
        return next;
      });
    }
  }, []);

  const run = useCallback(
    async (nextSeed: number) => {
      const myRun = ++runId.current;
      setBusy(true);
      setError(null);
      setChecks({});

      let list = generateNames({
        keywords: parsedKeywords,
        style,
        count: NAME_COUNT,
        seed: nextSeed,
      });

      // AI names: the visitor's own key if they saved one and asked us to use
      // it, else the platform gateway if they're signed in with OTM. A failure
      // here is never fatal — the built-in list is already computed.
      const wantsOwnKey = useAi && ai;
      const wantsPlatform = !ai && platformAi && account && usePlatformAi;
      let gotAi = 0;
      if (wantsOwnKey || wantsPlatform) {
        try {
          const aiNames = wantsOwnKey
            ? await generateWithAi(ai, parsedKeywords, style, 16)
            : await generateWithPlatformAi(parsedKeywords, style, 16);
          if (runId.current !== myRun) return;
          const seen = new Set(list.map((i) => i.name));
          const extra: Idea[] = aiNames
            .filter((n) => !seen.has(n))
            .map((name) => ({ name, strategy: "ai" as const, score: scoreName(name, parsedKeywords) }));
          list = [...extra, ...list].slice(0, NAME_COUNT + extra.length);
          gotAi = extra.length;
        } catch (err) {
          setError(
            `AI names unavailable (${err instanceof Error ? err.message : "unknown error"}). Showing built-in suggestions.`,
          );
        }
      }

      if (runId.current !== myRun) return;
      setIdeas(list);
      setAiCount(wantsOwnKey || wantsPlatform ? gotAi : null);
      setBusy(false);
      await lookup(domainsFor(list, tlds), myRun);
    },
    [account, ai, domainsFor, lookup, parsedKeywords, platformAi, style, tlds, useAi, usePlatformAi],
  );

  const onGenerate = () => {
    const next = seed + 1;
    setSeed(next);
    void run(next);
  };

  const toggleTld = (tld: string) => {
    setTlds((prev) => (prev.includes(tld) ? prev.filter((t) => t !== tld) : [...prev, tld]));
  };

  const showsUnverifiable = tlds.some((t) => UNVERIFIABLE_TLDS.includes(t));

  /** A name is "all taken" once every domain we checked for it resolved taken.
   *  Still-checking or unknown names stay visible — hiding is for certainty. */
  const isAllTaken = useCallback(
    (idea: Idea): boolean => {
      const ds = domainsFor([idea], tlds);
      return ds.length > 0 && ds.every((d) => checks[d]?.status === "taken");
    },
    [checks, domainsFor, tlds],
  );
  const visibleIdeas = hideTaken ? ideas.filter((i) => !isAllTaken(i)) : ideas;
  const hiddenCount = ideas.length - visibleIdeas.length;

  return (
    <>
      <div className="field">
        <label htmlFor="keywords">What&rsquo;s the business?</label>
        <input
          id="keywords"
          type="text"
          value={keywords}
          placeholder="auto repair, brake specialist — or just: bakery"
          onChange={(e) => setKeywords(e.target.value)}
          onKeyDown={(e) => {
            if (e.key === "Enter") onGenerate();
          }}
        />
        <p className="hint">
          A few words is plenty. Leave it empty and you&rsquo;ll get an abstract, category-free
          shortlist instead.
        </p>
      </div>

      <div className="field">
        <label>Style</label>
        <div className="chips">
          {STYLES.map((s) => (
            <button
              key={s.id}
              type="button"
              className="chip"
              aria-pressed={style === s.id}
              onClick={() => setStyle(s.id)}
            >
              {s.label}
              <span className="chip-note">{s.note}</span>
            </button>
          ))}
        </div>
      </div>

      <div className="field">
        <label>Extensions to check</label>
        <div className="chips">
          {TLDS.map((t) => (
            <button
              key={t.tld}
              type="button"
              className="chip"
              aria-pressed={tlds.includes(t.tld)}
              title={t.note}
              onClick={() => toggleTld(t.tld)}
            >
              .{t.tld}
            </button>
          ))}
        </div>
      </div>

      <div className="controls">
        <button className="primary" onClick={onGenerate} disabled={busy || tlds.length === 0}>
          {busy ? "Thinking…" : ideas.length ? "Show me more" : "Find names"}
        </button>

        <label
          style={{ display: "inline-flex", alignItems: "center", gap: 8, fontSize: 14, color: "var(--muted)" }}
        >
          Register at
          <select
            value={registrar}
            onChange={(e) => setRegistrar(e.target.value)}
            style={{ width: "auto", padding: "8px 10px", fontSize: 14 }}
          >
            {REGISTRARS.map((r) => (
              <option key={r.id} value={r.id} title={r.note}>
                {r.name}
              </option>
            ))}
          </select>
        </label>

        {ai ? (
          <label
            style={{ display: "inline-flex", alignItems: "center", gap: 8, fontSize: 14, color: "var(--muted)" }}
          >
            <input
              type="checkbox"
              checked={useAi}
              onChange={(e) => setUseAi(e.target.checked)}
              style={{ width: "auto" }}
            />
            Use my {ai.provider === "anthropic" ? "Claude" : "Gemini"} key
          </label>
        ) : platformAi && account ? (
          <label
            style={{ display: "inline-flex", alignItems: "center", gap: 8, fontSize: 14, color: "var(--muted)" }}
            title={`Signed in as ${account.email}`}
          >
            <input
              type="checkbox"
              checked={usePlatformAi}
              onChange={(e) => setUsePlatformAi(e.target.checked)}
              style={{ width: "auto" }}
            />
            AI names
            <button type="button" className="linkish" onClick={signOut} title={`Sign out ${account.email}`}>
              sign out
            </button>
          </label>
        ) : platformAi ? (
          <a className="signin" href={otmSsoUrl("/")} title="Free OTM account · adds AI-generated names">
            Sign in with OTM for AI names →
          </a>
        ) : null}
      </div>

      {tlds.length === 0 ? (
        <p className="notice info">Pick at least one extension to check.</p>
      ) : null}

      {signinNote ? <p className="notice warn">{signinNote}</p> : null}
      {error ? <p className="notice warn">{error}</p> : null}

      {showsUnverifiable && ideas.length > 0 ? (
        <p className="notice info">
          {UNVERIFIABLE_TLDS.filter((t) => tlds.includes(t))
            .map((t) => `.${t}`)
            .join(", ")}{" "}
          {UNVERIFIABLE_TLDS.filter((t) => tlds.includes(t)).length === 1 ? "publishes" : "publish"} no
          RDAP service, so those are checked with a DNS lookup instead and shown in amber as{" "}
          <em>probably free</em>. A registered-but-unused domain looks identical &mdash; confirm at
          the registrar before you count on one.
        </p>
      ) : null}

      {saved.length > 0 ? (
        <section className="wishlist" aria-label="Saved names">
          <div className="wishlist-head">
            <h2>
              Saved <span className="count">{saved.length}</span>
            </h2>
            <div className="wishlist-actions">
              <button type="button" className="mini" onClick={recheckSaved} disabled={rechecking}>
                {rechecking ? "Checking…" : "Re-check"}
              </button>
              <button type="button" className="mini" onClick={copySaved}>
                {copied ? "Copied" : "Copy list"}
              </button>
            </div>
          </div>
          <p className="hint">
            Kept in this browser only. Statuses are from the last time each name was checked
            &mdash; press Re-check before you commit.
          </p>
          <div className="results">
            {saved.map((entry) => (
              <SavedCard key={entry.name} entry={entry} registrar={registrar} onRemove={() => removeSaved(entry.name)} />
            ))}
          </div>
        </section>
      ) : null}

      {ideas.length === 0 ? (
        <p className="empty">
          {busy ? "Working…" : "Describe the business above and press Find names."}
        </p>
      ) : (
        <>
          <div className="results-bar">
            <span className="results-summary">
              {aiCount != null ? (
                <>
                  <span className="ai-badge">AI</span> {aiCount} {aiCount === 1 ? "name" : "names"} ·{" "}
                  {ideas.length - aiCount} built-in
                </>
              ) : (
                <>{ideas.length} names</>
              )}
              {hideTaken && hiddenCount > 0 ? <> · {hiddenCount} taken hidden</> : null}
            </span>
            <label className="results-toggle">
              <input type="checkbox" checked={hideTaken} onChange={(e) => toggleHideTaken(e.target.checked)} />
              Hide taken
            </label>
          </div>
          <div className="results">
            {visibleIdeas.map((idea) => (
              <NameCard
                key={idea.name}
                idea={idea}
                tlds={tlds}
                checks={checks}
                pending={pending}
                registrar={registrar}
                saved={savedNames.has(idea.hackTld && idea.hackStem ? `${idea.hackStem}.${idea.hackTld}` : idea.name)}
                onToggleSave={toggleSaved}
                hideTaken={hideTaken}
              />
            ))}
          </div>
        </>
      )}
    </>
  );
}

function NameCard({
  idea,
  tlds,
  checks,
  pending,
  registrar,
  saved,
  onToggleSave,
  hideTaken,
}: {
  idea: Idea;
  tlds: string[];
  checks: Record<string, DomainCheck>;
  pending: Set<string>;
  registrar: string;
  saved: boolean;
  onToggleSave: (name: string, domains: string[]) => void;
  hideTaken: boolean;
}) {
  const isHack = Boolean(idea.hackTld && idea.hackStem);
  const domains = isHack ? [`${idea.hackStem}.${idea.hackTld}`] : tlds.map((t) => `${idea.name}.${t}`);
  const saveKey = isHack ? domains[0] : idea.name;

  // Dim the whole card only when every extension we checked came back taken.
  const settled = domains.map((d) => checks[d]).filter(Boolean);
  const allTaken = settled.length === domains.length && settled.every((c) => c.status === "taken");

  return (
    <div className={`card${allTaken ? " is-taken" : ""}${saved ? " is-saved" : ""}`}>
      <div className="card-head">
        <div className="card-name">
          {isHack ? (
            <>
              {idea.hackStem}
              <span className="tld">.{idea.hackTld}</span>
            </>
          ) : (
            idea.name
          )}
        </div>
        <button
          type="button"
          className="save"
          aria-pressed={saved}
          title={saved ? "Remove from saved" : "Save for later"}
          aria-label={saved ? `Remove ${saveKey} from saved` : `Save ${saveKey}`}
          onClick={() => onToggleSave(saveKey, domains)}
        >
          {saved ? "★" : "☆"}
        </button>
      </div>

      {domains.map((domain) => {
        const check = checks[domain];
        const isPending = pending.has(domain) && !check;
        const status: Availability | "checking" = isPending ? "checking" : (check?.status ?? "unknown");
        const free = status === "available" || status === "unverified-available";
        if (hideTaken && status === "taken") return null;

        return (
          <div className="card-meta" key={domain}>
            <span className={`status ${status}`} title={check?.detail}>
              {statusIcon(status)} {isHack ? domain : `.${domain.slice(idea.name.length + 1)}`}{" "}
              <span style={{ fontWeight: 400 }}>{statusLabel(status)}</span>
            </span>
            {free ? (
              <a
                className="register-link"
                href={registerUrl(domain, registrar)}
                target="_blank"
                rel="noopener noreferrer"
              >
                Register →
              </a>
            ) : null}
          </div>
        );
      })}

      <span className="strategy">
        {idea.strategy === "ai" ? <span className="ai-badge">AI</span> : null} {strategyLabel(idea.strategy)}
      </span>
    </div>
  );
}

function SavedCard({
  entry,
  registrar,
  onRemove,
}: {
  entry: SavedName;
  registrar: string;
  onRemove: () => void;
}) {
  const isHack = entry.domains.length === 1 && entry.domains[0] === entry.name;
  const settled = entry.domains.map((d) => entry.checks[d]).filter(Boolean);
  const allTaken = settled.length === entry.domains.length && settled.every((c) => c.status === "taken");
  return (
    <div className={`card is-saved${allTaken ? " is-taken" : ""}`}>
      <div className="card-head">
        <div className="card-name">{entry.name}</div>
        <button
          type="button"
          className="save"
          aria-pressed
          title="Remove from saved"
          aria-label={`Remove ${entry.name} from saved`}
          onClick={onRemove}
        >
          ★
        </button>
      </div>
      {entry.domains.map((domain) => {
        const check = entry.checks[domain];
        const status: Availability = check?.status ?? "unknown";
        const free = status === "available" || status === "unverified-available";
        return (
          <div className="card-meta" key={domain}>
            <span className={`status ${status}`} title={check?.detail}>
              {statusIcon(status)} {isHack ? domain : `.${domain.slice(entry.name.length + 1)}`}{" "}
              <span style={{ fontWeight: 400 }}>{statusLabel(status)}</span>
            </span>
            {free ? (
              <a className="register-link" href={registerUrl(domain, registrar)} target="_blank" rel="noopener noreferrer">
                Register →
              </a>
            ) : null}
          </div>
        );
      })}
    </div>
  );
}

function statusIcon(status: Availability | "checking"): string {
  switch (status) {
    case "available":
      return "●";
    case "unverified-available":
      return "◐";
    case "taken":
      return "○";
    case "checking":
      return "…";
    default:
      return "?";
  }
}

function statusLabel(status: Availability | "checking"): string {
  switch (status) {
    case "available":
      return "free";
    case "unverified-available":
      return "probably free";
    case "taken":
      return "taken";
    case "checking":
      return "checking";
    default:
      return "unclear";
  }
}

function strategyLabel(strategy: Idea["strategy"]): string {
  switch (strategy) {
    case "compound":
      return "compound";
    case "suffix-word":
      return "compound";
    case "action":
      return "call to action";
    case "blend":
      return "blend";
    case "coined":
      return "coined";
    case "clipped":
      return "clipped";
    case "root":
      return "classical root";
    case "hack":
      return "domain hack";
    case "ai":
      return "generated";
    default:
      return "";
  }
}