import { useEffect, useState, useCallback } from "react";
import { useTranslation } from "react-i18next";
import {
  Info,
  RefreshCw,
  Download,
  CheckCircle,
  AlertCircle,
  RotateCcw,
  Loader2,
} from "lucide-react";
import { useUpdater } from "../../hooks/useUpdater";

export default function UpdateCard() {
  const { t, i18n } = useTranslation();
  const { state, checkForUpdate, downloadAndInstall, installAndRestart } =
    useUpdater();
  const [releaseNotes, setReleaseNotes] = useState<string | null>(null);

  const fetchReleaseNotes = useCallback(
    (targetVersion: string) => {
      const file =
        i18n.language === "fr" ? "/CHANGELOG.fr.md" : "/CHANGELOG.md";
      fetch(file)
        .then((r) => r.text())
        .then((text) => {
          const escaped = targetVersion.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
          const re = new RegExp(
            `^## \\[?${escaped}\\]?.*$\\n([\\s\\S]*?)(?=^## |$(?!\\n))`,
            "m",
          );
          const match = text.match(re);
          setReleaseNotes(match ? match[1].trim() : null);
        })
        .catch(() => setReleaseNotes(null));
    },
    [i18n.language],
  );

  useEffect(() => {
    if (state.status === "available" && state.version) {
      fetchReleaseNotes(state.version);
    }
  }, [state.status, state.version, fetchReleaseNotes]);

  const progressPercent =
    state.contentLength && state.contentLength > 0
      ? Math.round((state.progress / state.contentLength) * 100)
      : null;

  return (
    <div className="bg-[var(--card)] border border-[var(--border)] rounded-xl p-6 space-y-4">
      <h2 className="text-lg font-semibold flex items-center gap-2">
        <Info size={18} />
        {t("settings.updates.title")}
      </h2>

      {state.status === "idle" && (
        <button
          onClick={checkForUpdate}
          className="flex items-center gap-2 px-4 py-2 bg-[var(--primary)] text-white rounded-lg hover:opacity-90 transition-opacity"
        >
          <RefreshCw size={16} />
          {t("settings.updates.checkButton")}
        </button>
      )}

      {state.status === "checking" && (
        <div className="flex items-center gap-2 text-[var(--muted-foreground)]">
          <Loader2 size={16} className="animate-spin" />
          {t("settings.updates.checking")}
        </div>
      )}

      {state.status === "notEntitled" && (
        <div className="flex items-start gap-2 text-sm text-[var(--muted-foreground)]">
          <AlertCircle size={16} className="mt-0.5 shrink-0" />
          <p>{t("settings.updates.notEntitled")}</p>
        </div>
      )}

      {state.status === "upToDate" && (
        <div className="flex items-center justify-between">
          <div className="flex items-center gap-2 text-[var(--positive)]">
            <CheckCircle size={16} />
            {t("settings.updates.upToDate")}
          </div>
          <button
            onClick={checkForUpdate}
            className="text-sm text-[var(--muted-foreground)] hover:text-[var(--foreground)] transition-colors"
          >
            <RefreshCw size={14} />
          </button>
        </div>
      )}

      {state.status === "available" && (
        <div className="space-y-3">
          <p>
            {t("settings.updates.available", { version: state.version })}
          </p>
          {(() => {
            const notes = releaseNotes || state.body;
            if (!notes) return null;
            return (
              <div className="space-y-2">
                <h3 className="text-sm font-semibold text-[var(--foreground)]">
                  {t("settings.updates.releaseNotes")}
                </h3>
                <div className="max-h-48 overflow-y-auto rounded-lg bg-[var(--background)] border border-[var(--border)] p-3 text-sm text-[var(--muted-foreground)] space-y-1">
                  {notes.split("\n").map((line, i) => {
                    const trimmed = line.trim();
                    if (!trimmed) return <div key={i} className="h-2" />;
                    if (trimmed.startsWith("### "))
                      return (
                        <p
                          key={i}
                          className="font-semibold text-[var(--foreground)] mt-2"
                        >
                          {trimmed.slice(4)}
                        </p>
                      );
                    if (trimmed.startsWith("## "))
                      return (
                        <p
                          key={i}
                          className="font-bold text-[var(--foreground)] mt-2"
                        >
                          {trimmed.slice(3)}
                        </p>
                      );
                    if (trimmed.startsWith("- "))
                      return (
                        <p key={i} className="pl-3">
                          {"• "}
                          {trimmed.slice(2).replace(/\*\*(.+?)\*\*/g, "$1")}
                        </p>
                      );
                    return <p key={i}>{trimmed}</p>;
                  })}
                </div>
              </div>
            );
          })()}
          <button
            onClick={downloadAndInstall}
            className="flex items-center gap-2 px-4 py-2 bg-[var(--primary)] text-white rounded-lg hover:opacity-90 transition-opacity"
          >
            <Download size={16} />
            {t("settings.updates.downloadButton")}
          </button>
        </div>
      )}

      {state.status === "downloading" && (
        <div className="space-y-2">
          <div className="flex items-center gap-2 text-[var(--muted-foreground)]">
            <Loader2 size={16} className="animate-spin" />
            {t("settings.updates.downloading")}
            {progressPercent !== null && <span>{progressPercent}%</span>}
          </div>
          <div className="w-full bg-[var(--border)] rounded-full h-2">
            <div
              className="bg-[var(--primary)] h-2 rounded-full transition-all duration-300"
              style={{ width: `${progressPercent ?? 0}%` }}
            />
          </div>
        </div>
      )}

      {state.status === "readyToInstall" && (
        <div className="space-y-3">
          <p className="text-[var(--positive)]">
            {t("settings.updates.readyToInstall")}
          </p>
          <button
            onClick={installAndRestart}
            className="flex items-center gap-2 px-4 py-2 bg-[var(--positive)] text-white rounded-lg hover:opacity-90 transition-opacity"
          >
            <RotateCcw size={16} />
            {t("settings.updates.installButton")}
          </button>
        </div>
      )}

      {state.status === "installing" && (
        <div className="flex items-center gap-2 text-[var(--muted-foreground)]">
          <Loader2 size={16} className="animate-spin" />
          {t("settings.updates.installing")}
        </div>
      )}

      {state.status === "error" && (
        <div className="space-y-3">
          <div className="flex items-center gap-2 text-[var(--negative)]">
            <AlertCircle size={16} />
            {t("settings.updates.error")}
          </div>
          <p className="text-sm text-[var(--muted-foreground)]">{state.error}</p>
          <button
            onClick={checkForUpdate}
            className="flex items-center gap-2 px-4 py-2 border border-[var(--border)] rounded-lg hover:bg-[var(--border)] transition-colors"
          >
            <RotateCcw size={16} />
            {t("settings.updates.retryButton")}
          </button>
        </div>
      )}
    </div>
  );
}