import { DragEvent, ReactElement, useEffect, useMemo, useRef, useState } from "react";
import type { AppSettings, DebridFallbackProvider, DebridProvider, DownloadItem, PackageEntry, UiSnapshot, UpdateCheckResult } from "../shared/types";

type Tab = "collector" | "downloads" | "settings";

const emptySnapshot = (): UiSnapshot => ({
  settings: {
    token: "",
    megaLogin: "",
    megaPassword: "",
    bestToken: "",
    allDebridToken: "",
    rememberToken: true,
    providerPrimary: "realdebrid",
    providerSecondary: "megadebrid",
    providerTertiary: "bestdebrid",
    autoProviderFallback: true,
    outputDir: "",
    packageName: "",
    autoExtract: true,
    extractDir: "",
    createExtractSubfolder: true,
    hybridExtract: true,
    cleanupMode: "none",
    extractConflictMode: "overwrite",
    removeLinkFilesAfterExtract: false,
    removeSamplesAfterExtract: false,
    enableIntegrityCheck: true,
    autoResumeOnStart: true,
    autoReconnect: false,
    reconnectWaitSeconds: 45,
    completedCleanupPolicy: "never",
    maxParallel: 4,
    speedLimitEnabled: false,
    speedLimitKbps: 0,
    speedLimitMode: "global",
    updateRepo: "",
    autoUpdateCheck: true
  },
  session: {
    version: 2,
    packageOrder: [],
    packages: {},
    items: {},
    runStartedAt: 0,
    totalDownloadedBytes: 0,
    summaryText: "",
    reconnectUntil: 0,
    reconnectReason: "",
    paused: false,
    running: false,
    updatedAt: Date.now()
  },
  summary: null,
  speedText: "Geschwindigkeit: 0 B/s",
  etaText: "ETA: --",
  canStart: true,
  canStop: false,
  canPause: false
});

const cleanupLabels: Record<string, string> = {
  never: "Nie",
  immediate: "Sofort",
  on_start: "Beim App-Start",
  package_done: "Sobald Paket fertig ist"
};

const providerLabels: Record<DebridProvider, string> = {
  realdebrid: "Real-Debrid",
  megadebrid: "Mega-Debrid",
  bestdebrid: "BestDebrid",
  alldebrid: "AllDebrid"
};

const fallbackProviderOptions: Array<{ value: DebridFallbackProvider; label: string }> = [
  { value: "none", label: "Kein Fallback" },
  { value: "realdebrid", label: providerLabels.realdebrid },
  { value: "megadebrid", label: providerLabels.megadebrid },
  { value: "bestdebrid", label: providerLabels.bestdebrid },
  { value: "alldebrid", label: providerLabels.alldebrid }
];

function formatSpeedMbps(speedBps: number): string {
  const mbps = Math.max(0, speedBps) / (1024 * 1024);
  return `${mbps.toFixed(2)} MB/s`;
}

export function App(): ReactElement {
  const [snapshot, setSnapshot] = useState<UiSnapshot>(emptySnapshot);
  const [tab, setTab] = useState<Tab>("collector");
  const [linksRaw, setLinksRaw] = useState("");
  const [statusToast, setStatusToast] = useState("");
  const [settingsDraft, setSettingsDraft] = useState<AppSettings>(emptySnapshot().settings);
  const latestStateRef = useRef<UiSnapshot | null>(null);
  const stateFlushTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  const toastTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  const showToast = (message: string, timeoutMs = 2200): void => {
    setStatusToast(message);
    if (toastTimerRef.current) {
      clearTimeout(toastTimerRef.current);
    }
    toastTimerRef.current = setTimeout(() => {
      setStatusToast("");
      toastTimerRef.current = null;
    }, timeoutMs);
  };

  useEffect(() => {
    let unsubscribe: (() => void) | null = null;
    void window.rd.getSnapshot().then((state) => {
      setSnapshot(state);
      setSettingsDraft(state.settings);
      if (state.settings.autoUpdateCheck) {
        void window.rd.checkUpdates().then((result) => {
          void handleUpdateResult(result, "startup");
        }).catch(() => undefined);
      }
    }).catch((error) => {
      showToast(`Snapshot konnte nicht geladen werden: ${String(error)}`, 2800);
    });
    unsubscribe = window.rd.onStateUpdate((state) => {
      latestStateRef.current = state;
      if (stateFlushTimerRef.current) {
        return;
      }
      stateFlushTimerRef.current = setTimeout(() => {
        stateFlushTimerRef.current = null;
        if (latestStateRef.current) {
          setSnapshot(latestStateRef.current);
          latestStateRef.current = null;
        }
      }, 220);
    });
    return () => {
      if (stateFlushTimerRef.current) {
        clearTimeout(stateFlushTimerRef.current);
        stateFlushTimerRef.current = null;
      }
      if (toastTimerRef.current) {
        clearTimeout(toastTimerRef.current);
        toastTimerRef.current = null;
      }
      if (unsubscribe) {
        unsubscribe();
      }
    };
  }, []);

  const packages = useMemo(() => snapshot.session.packageOrder
    .map((id: string) => snapshot.session.packages[id])
    .filter(Boolean), [snapshot]);

  const handleUpdateResult = async (result: UpdateCheckResult, source: "manual" | "startup"): Promise<void> => {
    if (result.error) {
      if (source === "manual") {
        showToast(`Update-Check fehlgeschlagen: ${result.error}`, 2800);
      }
      return;
    }

    if (!result.updateAvailable) {
      if (source === "manual") {
        showToast(`Kein Update verfügbar (v${result.currentVersion})`, 2000);
      }
      return;
    }

    const approved = window.confirm(
      `Update verfügbar: ${result.latestTag} (aktuell v${result.currentVersion})\n\nJetzt automatisch herunterladen und installieren?`
    );
    if (!approved) {
      showToast(`Update verfügbar: ${result.latestTag}`, 2600);
      return;
    }

    const install = await window.rd.installUpdate();
    if (install.started) {
      showToast("Updater gestartet - App wird geschlossen", 2600);
      return;
    }

    showToast(`Auto-Update fehlgeschlagen: ${install.message}`, 3200);
  };

  const onSaveSettings = async (): Promise<void> => {
    try {
      await window.rd.updateSettings(settingsDraft);
      showToast("Settings gespeichert", 1800);
    } catch (error) {
      showToast(`Settings konnten nicht gespeichert werden: ${String(error)}`, 2800);
    }
  };

  const onCheckUpdates = async (): Promise<void> => {
    try {
      const result = await window.rd.checkUpdates();
      await handleUpdateResult(result, "manual");
    } catch (error) {
      showToast(`Update-Check fehlgeschlagen: ${String(error)}`, 2800);
    }
  };

  const onAddLinks = async (): Promise<void> => {
    try {
      await window.rd.updateSettings(settingsDraft);
      const result = await window.rd.addLinks({ rawText: linksRaw, packageName: settingsDraft.packageName });
      if (result.addedLinks > 0) {
        showToast(`${result.addedPackages} Paket(e), ${result.addedLinks} Link(s) hinzugefügt`);
        setLinksRaw("");
      } else {
        showToast("Keine gültigen Links gefunden");
      }
    } catch (error) {
      showToast(`Fehler beim Hinzufügen: ${String(error)}`, 2600);
    }
  };

  const onImportDlc = async (): Promise<void> => {
    try {
      const files = await window.rd.pickContainers();
      if (files.length === 0) {
        return;
      }
      await window.rd.updateSettings(settingsDraft);
      const result = await window.rd.addContainers(files);
      showToast(`DLC importiert: ${result.addedPackages} Paket(e), ${result.addedLinks} Link(s)`);
    } catch (error) {
      showToast(`Fehler beim DLC-Import: ${String(error)}`, 2600);
    }
  };

  const onDrop = async (event: DragEvent<HTMLTextAreaElement>): Promise<void> => {
    event.preventDefault();
    const files = Array.from(event.dataTransfer.files ?? []) as File[];
    const dlc = files
      .filter((file) => file.name.toLowerCase().endsWith(".dlc"))
      .map((file) => (file as unknown as { path?: string }).path)
      .filter((value): value is string => !!value);
    if (dlc.length === 0) {
      return;
    }
    try {
      await window.rd.updateSettings(settingsDraft);
      const result = await window.rd.addContainers(dlc);
      showToast(`Drag-and-Drop: ${result.addedPackages} Paket(e), ${result.addedLinks} Link(s)`);
    } catch (error) {
      showToast(`Fehler bei Drag-and-Drop: ${String(error)}`, 2600);
    }
  };

  const setBool = (key: keyof AppSettings, value: boolean): void => {
    setSettingsDraft((prev: AppSettings) => ({ ...prev, [key]: value }));
  };

  const setText = (key: keyof AppSettings, value: string): void => {
    setSettingsDraft((prev: AppSettings) => ({ ...prev, [key]: value }));
  };

  const setNum = (key: keyof AppSettings, value: number): void => {
    setSettingsDraft((prev: AppSettings) => ({ ...prev, [key]: value }));
  };

  const performQuickAction = async (action: () => Promise<unknown>): Promise<void> => {
    try {
      await action();
    } catch (error) {
      showToast(`Fehler: ${String(error)}`, 2600);
    }
  };

  return (
    <div className="app-shell">
      <header className="top-header">
        <div className="title-block">
          <h1>Debrid Download Manager</h1>
          <span>Multi-Provider Workflow</span>
        </div>
        <div className="metrics">
          <div>{snapshot.speedText}</div>
          <div>{snapshot.etaText}</div>
        </div>
      </header>

      <section className="control-strip">
        <div className="buttons">
          <button
            className="btn accent"
            disabled={!snapshot.canStart}
            onClick={async () => {
              await performQuickAction(async () => {
                await window.rd.updateSettings(settingsDraft);
                await window.rd.start();
              });
            }}
          >Start</button>
          <button className="btn" disabled={!snapshot.canPause} onClick={() => { void performQuickAction(() => window.rd.togglePause()); }}>
            {snapshot.session.paused ? "Resume" : "Pause"}
          </button>
          <button className="btn" disabled={!snapshot.canStop} onClick={() => { void performQuickAction(() => window.rd.stop()); }}>Stop</button>
          <button className="btn" onClick={() => { void performQuickAction(() => window.rd.clearAll()); }}>Alles leeren</button>
        </div>
        <div className="speed-config">
          <label>
            <input
              type="checkbox"
              checked={settingsDraft.speedLimitEnabled}
              onChange={(event) => setBool("speedLimitEnabled", event.target.checked)}
            />
            Speed-Limit
          </label>
          <input
            type="number"
            min={0}
            max={500000}
            value={settingsDraft.speedLimitKbps}
            onChange={(event) => setNum("speedLimitKbps", Number(event.target.value) || 0)}
          />
          <span>KB/s</span>
          <select value={settingsDraft.speedLimitMode} onChange={(event) => setText("speedLimitMode", event.target.value)}>
            <option value="global">global</option>
            <option value="per_download">per_download</option>
          </select>
        </div>
      </section>

      <nav className="tabs">
        <button className={tab === "collector" ? "tab active" : "tab"} onClick={() => setTab("collector")}>Linksammler</button>
        <button className={tab === "downloads" ? "tab active" : "tab"} onClick={() => setTab("downloads")}>Downloads</button>
        <button className={tab === "settings" ? "tab active" : "tab"} onClick={() => setTab("settings")}>Settings</button>
      </nav>

      <main className="tab-content">
        {tab === "collector" && (
          <section className="grid-two">
            <article className="card wide">
              <h3>Linksammler</h3>
              <div className="link-actions">
                <button className="btn" onClick={onImportDlc}>DLC import</button>
                <button className="btn accent" onClick={onAddLinks}>Zur Queue hinzufügen</button>
              </div>
              <textarea
                value={linksRaw}
                onChange={(event) => setLinksRaw(event.target.value)}
                onDragOver={(event) => event.preventDefault()}
                onDrop={onDrop}
                placeholder="# package: Release-Name\nhttps://...\nhttps://..."
              />
              <p className="hint">.dlc einfach auf das Feld ziehen oder per Button importieren.</p>
            </article>
          </section>
        )}

        {tab === "downloads" && (
          <section className="downloads-view">
            {packages.length === 0 && <div className="empty">Noch keine Pakete in der Queue.</div>}
            {packages.map((pkg) => (
              <PackageCard
                key={pkg.id}
                pkg={pkg}
                items={pkg.itemIds.map((id) => snapshot.session.items[id]).filter(Boolean)}
                onCancel={() => { void performQuickAction(() => window.rd.cancelPackage(pkg.id)); }}
              />
            ))}
          </section>
        )}

        {tab === "settings" && (
          <section className="settings-shell">
            <article className="card settings-toolbar">
              <div className="settings-toolbar-copy">
                <h3>Einstellungen</h3>
                <span>Kompakt, schnell auffindbar und direkt speicherbar.</span>
              </div>
              <div className="settings-toolbar-actions">
                <button className="btn" onClick={onCheckUpdates}>Updates prüfen</button>
                <button className="btn accent" onClick={onSaveSettings}>Settings speichern</button>
              </div>
            </article>

            <section className="settings-grid">
              <article className="card settings-card">
                <h3>Provider & Zugang</h3>
                <label>Real-Debrid API Token</label>
                <input type="password" value={settingsDraft.token} onChange={(event) => setText("token", event.target.value)} />
                <label>Mega-Debrid Login</label>
                <input value={settingsDraft.megaLogin} onChange={(event) => setText("megaLogin", event.target.value)} />
                <label>Mega-Debrid Passwort</label>
                <input type="password" value={settingsDraft.megaPassword} onChange={(event) => setText("megaPassword", event.target.value)} />
                <label>BestDebrid API Token</label>
                <input type="password" value={settingsDraft.bestToken} onChange={(event) => setText("bestToken", event.target.value)} />
                <label>AllDebrid API Key</label>
                <input type="password" value={settingsDraft.allDebridToken} onChange={(event) => setText("allDebridToken", event.target.value)} />

                <div className="field-grid three">
                  <div>
                    <label>Primär</label>
                    <select value={settingsDraft.providerPrimary} onChange={(event) => setText("providerPrimary", event.target.value)}>
                      {Object.entries(providerLabels).map(([key, label]) => (
                        <option key={key} value={key}>{label}</option>
                      ))}
                    </select>
                  </div>
                  <div>
                    <label>Sekundär</label>
                    <select value={settingsDraft.providerSecondary} onChange={(event) => setText("providerSecondary", event.target.value)}>
                      {fallbackProviderOptions.map((option) => (
                        <option key={option.value} value={option.value}>{option.label}</option>
                      ))}
                    </select>
                  </div>
                  <div>
                    <label>Tertiär</label>
                    <select value={settingsDraft.providerTertiary} onChange={(event) => setText("providerTertiary", event.target.value)}>
                      {fallbackProviderOptions.map((option) => (
                        <option key={option.value} value={option.value}>{option.label}</option>
                      ))}
                    </select>
                  </div>
                </div>

                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.autoProviderFallback} onChange={(event) => setBool("autoProviderFallback", event.target.checked)} /> Bei Fehler/Fair-Use automatisch zum nächsten Provider wechseln</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.rememberToken} onChange={(event) => setBool("rememberToken", event.target.checked)} /> Zugangsdaten lokal speichern</label>
              </article>

              <article className="card settings-card">
                <h3>Pfade & Paketierung</h3>
                <label>Download-Ordner</label>
                <div className="input-row">
                  <input value={settingsDraft.outputDir} onChange={(event) => setText("outputDir", event.target.value)} />
                  <button
                    className="btn"
                    onClick={() => {
                      void performQuickAction(async () => {
                        const selected = await window.rd.pickFolder();
                        if (selected) {
                          setText("outputDir", selected);
                        }
                      });
                    }}
                  >Wählen</button>
                </div>
                <label>Paketname (optional)</label>
                <input value={settingsDraft.packageName} onChange={(event) => setText("packageName", event.target.value)} />
                <label>Entpacken nach</label>
                <div className="input-row">
                  <input value={settingsDraft.extractDir} onChange={(event) => setText("extractDir", event.target.value)} />
                  <button
                    className="btn"
                    onClick={() => {
                      void performQuickAction(async () => {
                        const selected = await window.rd.pickFolder();
                        if (selected) {
                          setText("extractDir", selected);
                        }
                      });
                    }}
                  >Wählen</button>
                </div>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.autoExtract} onChange={(event) => setBool("autoExtract", event.target.checked)} /> Auto-Extract</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.hybridExtract} onChange={(event) => setBool("hybridExtract", event.target.checked)} /> Hybrid-Extract</label>
              </article>

              <article className="card settings-card">
                <h3>Queue, Limits & Reconnect</h3>
                <div className="field-grid two">
                  <div>
                    <label>Max. Downloads</label>
                    <input type="number" min={1} max={50} value={settingsDraft.maxParallel} onChange={(event) => setNum("maxParallel", Number(event.target.value) || 1)} />
                  </div>
                  <div>
                    <label>Reconnect-Wartezeit (Sek.)</label>
                    <input type="number" min={10} max={600} value={settingsDraft.reconnectWaitSeconds} onChange={(event) => setNum("reconnectWaitSeconds", Number(event.target.value) || 45)} />
                  </div>
                </div>
                <div className="field-grid two">
                  <div>
                    <label>Speed-Limit (KB/s)</label>
                    <input type="number" min={0} max={500000} value={settingsDraft.speedLimitKbps} onChange={(event) => setNum("speedLimitKbps", Number(event.target.value) || 0)} />
                  </div>
                  <div>
                    <label>Speed-Modus</label>
                    <select value={settingsDraft.speedLimitMode} onChange={(event) => setText("speedLimitMode", event.target.value)}>
                      <option value="global">global</option>
                      <option value="per_download">per_download</option>
                    </select>
                  </div>
                </div>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.speedLimitEnabled} onChange={(event) => setBool("speedLimitEnabled", event.target.checked)} /> Speed-Limit aktivieren</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.autoReconnect} onChange={(event) => setBool("autoReconnect", event.target.checked)} /> Automatischer Reconnect</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.autoResumeOnStart} onChange={(event) => setBool("autoResumeOnStart", event.target.checked)} /> Auto-Resume beim Start</label>
              </article>

              <article className="card settings-card">
                <h3>Integrität, Cleanup & Updates</h3>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.enableIntegrityCheck} onChange={(event) => setBool("enableIntegrityCheck", event.target.checked)} /> SFV/CRC/MD5/SHA1 prüfen</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.removeLinkFilesAfterExtract} onChange={(event) => setBool("removeLinkFilesAfterExtract", event.target.checked)} /> Link-Dateien nach Entpacken entfernen</label>
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.removeSamplesAfterExtract} onChange={(event) => setBool("removeSamplesAfterExtract", event.target.checked)} /> Samples nach Entpacken entfernen</label>
                <label>Fertiggestellte Downloads entfernen</label>
                <select value={settingsDraft.completedCleanupPolicy} onChange={(event) => setText("completedCleanupPolicy", event.target.value)}>
                  {Object.entries(cleanupLabels).map(([key, label]) => (
                    <option key={key} value={key}>{label}</option>
                  ))}
                </select>
                <div className="field-grid two">
                  <div>
                    <label>Cleanup nach Entpacken</label>
                    <select value={settingsDraft.cleanupMode} onChange={(event) => setText("cleanupMode", event.target.value)}>
                      <option value="none">keine Archive löschen</option>
                      <option value="trash">Archive in Papierkorb</option>
                      <option value="delete">Archive löschen</option>
                    </select>
                  </div>
                  <div>
                    <label>Konfliktmodus</label>
                    <select value={settingsDraft.extractConflictMode} onChange={(event) => setText("extractConflictMode", event.target.value)}>
                      <option value="overwrite">überschreiben</option>
                      <option value="skip">überspringen</option>
                      <option value="rename">umbenennen</option>
                      <option value="ask">nachfragen</option>
                    </select>
                  </div>
                </div>
                <label>GitHub Repo</label>
                <input value={settingsDraft.updateRepo} onChange={(event) => setText("updateRepo", event.target.value)} />
                <label className="toggle-line"><input type="checkbox" checked={settingsDraft.autoUpdateCheck} onChange={(event) => setBool("autoUpdateCheck", event.target.checked)} /> Beim Start auf Updates prüfen</label>
              </article>
            </section>
          </section>
        )}
      </main>

      {statusToast && <div className="toast">{statusToast}</div>}
    </div>
  );
}

function PackageCard({ pkg, items, onCancel }: { pkg: PackageEntry; items: DownloadItem[]; onCancel: () => void }): ReactElement {
  const done = items.filter((item) => item.status === "completed").length;
  const failed = items.filter((item) => item.status === "failed").length;
  const cancelled = items.filter((item) => item.status === "cancelled").length;
  const total = Math.max(1, items.length);
  const progress = Math.floor((done / total) * 100);

  return (
    <article className="package-card">
      <header>
        <div>
          <h4>{pkg.name}</h4>
          <span>{done}/{total} fertig · {failed} Fehler · {cancelled} abgebrochen</span>
        </div>
        <button className="btn danger" onClick={onCancel}>Paket abbrechen</button>
      </header>
      <div className="progress">
        <div style={{ width: `${progress}%` }} />
      </div>
      <table>
        <thead>
          <tr>
            <th className="col-file">Datei</th>
            <th className="col-provider">Provider</th>
            <th className="col-status">Status</th>
            <th className="col-progress">Fortschritt</th>
            <th className="col-speed">Speed</th>
            <th className="col-retries">Retries</th>
          </tr>
        </thead>
        <tbody>
          {items.map((item) => (
            <tr key={item.id}>
              <td className="col-file" title={item.fileName}>{item.fileName}</td>
              <td className="col-provider">{item.provider ? providerLabels[item.provider] : "-"}</td>
              <td className="col-status" title={item.fullStatus}>{item.fullStatus}</td>
              <td className="col-progress num">{item.progressPercent}%</td>
              <td className="col-speed num">{formatSpeedMbps(item.speedBps)}</td>
              <td className="col-retries num">{item.retries}</td>
            </tr>
          ))}
        </tbody>
      </table>
    </article>
  );
}