import { useEffect, useMemo, useState } from "react";
import { CheckCircle2, FileAudio, FolderOpen, Gauge, Music2 } from "lucide-react";
import { Button } from "../components/Button";
import { FileDropzone } from "../components/FileDropzone";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "../components/Select";
import { convertAudioFileToMp3 } from "../helpers/audioProcessing";
import {
  downloadBlob,
  sanitizeFilename,
  saveBlobToDirectory,
  type WritableDirectoryHandle,
} from "../helpers/mp3Tags";
import {
  ensureDirectoryWritePermission,
  loadOutputDirectory,
  saveOutputDirectory,
} from "../helpers/directoryStore";
import { loadSpotiRipSettings } from "../helpers/spotiripSettings";
import { addLibraryHistory } from "../helpers/libraryHistory";
import styles from "./convert.module.css";
import { MobileNav } from "../components/MobileNav";

type ConvertItem = {
  id: string;
  file: File;
  status: "ready" | "converting" | "saved" | "error";
  output?: string;
  error?: string;
};

export default function ConvertPage() {
  const [settings] = useState(() => loadSpotiRipSettings());
  const [items, setItems] = useState<ConvertItem[]>([]);
  const [bitrate, setBitrate] = useState(settings.mp3Bitrate);
  const [directory, setDirectory] = useState<WritableDirectoryHandle>();
  const [working, setWorking] = useState(false);
  const [message, setMessage] = useState<string>();

  useEffect(() => {
    loadOutputDirectory().then(setDirectory).catch(() => undefined);
  }, []);

  const readyCount = useMemo(() => items.filter((item) => item.status === "ready" || item.status === "error").length, [items]);

  function addFiles(files: File[]) {
    setItems((current) => [
      ...current,
      ...files
        .filter((file) => !current.some((item) => item.id === `${file.name}-${file.size}-${file.lastModified}`))
        .map((file) => ({
          id: `${file.name}-${file.size}-${file.lastModified}`,
          file,
          status: "ready" as const,
        })),
    ]);
  }

  async function chooseFolder() {
    const picker = (window as typeof window & {
      showDirectoryPicker?: () => Promise<WritableDirectoryHandle>;
    }).showDirectoryPicker;
    if (!picker) {
      setMessage("Direct folder writing is unavailable in this browser; normal downloads will be used.");
      return;
    }
    try {
      const selected = await picker();
      setDirectory(selected);
      await saveOutputDirectory(selected);
      setMessage(`Output folder: ${selected.name}`);
    } catch {
    }
  }

  async function convertAll() {
    const pending = items.filter((item) => item.status === "ready" || item.status === "error");
    if (!pending.length || working) return;
    setWorking(true);
    setMessage(undefined);

    let activeDirectory = directory;
    if (activeDirectory && !(await ensureDirectoryWritePermission(activeDirectory))) {
      activeDirectory = undefined;
      setDirectory(undefined);
      setMessage("Folder permission was not granted; converted files will download normally.");
    }

    let completed = 0;
    for (const item of pending) {
      setItems((current) => current.map((entry) => entry.id === item.id ? { ...entry, status: "converting", error: undefined } : entry));
      try {
        const mp3 = await convertAudioFileToMp3(item.file, bitrate);
        const base = sanitizeFilename(item.file.name.replace(/\.[^.]+$/, "")) || "Converted Audio";
        const filename = base + ".mp3";
        const output = activeDirectory
          ? await saveBlobToDirectory(activeDirectory, filename, mp3)
          : (downloadBlob(filename, mp3), filename);
        setItems((current) => current.map((entry) => entry.id === item.id ? { ...entry, status: "saved", output } : entry));
        completed += 1;
      } catch (reason) {
        const detail = reason instanceof Error ? reason.message : "Conversion failed.";
        setItems((current) => current.map((entry) => entry.id === item.id ? { ...entry, status: "error", error: detail } : entry));
      }
    }

    if (completed > 0) {
      addLibraryHistory({
        kind: "convert",
        title: `Converted ${completed} file${completed === 1 ? "" : "s"} to MP3`,
        trackCount: completed,
      });
      setMessage(
        activeDirectory
          ? `Converted ${completed} file${completed === 1 ? "" : "s"} to “${activeDirectory.name}”.`
          : `Converted ${completed} file${completed === 1 ? "" : "s"} and prepared browser downloads.`,
      );
    }
    setWorking(false);
  }

  return (
    <main className={styles.page}>
      <header className={styles.topbar}>
        <span>Local Converter</span>
      </header>

      <section className={styles.heading}>
        <div>
          <span>LOCAL AUDIO TOOLS</span>
          <h1>Convert to MP3</h1>
          <p>Convert audio files on your device without uploading the full source file to SpotiRip.</p>
        </div>
        <div className={styles.controls}>
          <div className={styles.bitrate}>
            <Gauge size={16} />
            <Select value={String(bitrate)} onValueChange={(value) => setBitrate(Number(value) as 128 | 192 | 256 | 320)}>
              <SelectTrigger aria-label="MP3 bitrate"><SelectValue /></SelectTrigger>
              <SelectContent>
                <SelectItem value="128">128 kbps</SelectItem>
                <SelectItem value="192">192 kbps</SelectItem>
                <SelectItem value="256">256 kbps</SelectItem>
                <SelectItem value="320">320 kbps</SelectItem>
              </SelectContent>
            </Select>
          </div>
          <Button variant="outline" onClick={chooseFolder}><FolderOpen size={16} /> {directory?.name || "Output folder"}</Button>
        </div>
      </section>

      {message ? <div className={styles.notice}>{message}</div> : null}

      <section className={styles.panel}>
        <FileDropzone
          accept=".wav,.m4a,.aac,.ogg,.mp3,audio/wav,audio/mp4,audio/aac,audio/ogg,audio/mpeg"
          maxFiles={100}
          maxSize={250 * 1024 * 1024}
          onFilesSelected={addFiles}
          icon={<FileAudio size={38} />}
          title="Drop audio files here"
          subtitle="WAV, M4A, AAC, OGG or MP3 · conversion happens on this device"
        />

        <div className={styles.toolbar}>
          <span>{items.length} file{items.length === 1 ? "" : "s"} · {readyCount} waiting</span>
          <Button disabled={!readyCount || working} onClick={convertAll}>
            <Music2 size={16} /> {working ? "Converting…" : "Convert to MP3"}
          </Button>
        </div>

        <div className={styles.list}>
          {items.map((item, index) => (
            <div className={styles.row} key={item.id}>
              <span className={styles.index}>{String(index + 1).padStart(2, "0")}</span>
              <div>
                <strong>{item.file.name}</strong>
                <span>{(item.file.size / 1024 / 1024).toFixed(1)} MB</span>
              </div>
              <div className={styles.state}>
                {item.status === "saved" ? <><CheckCircle2 size={14} /> {item.output}</> :
                 item.status === "converting" ? "Converting…" :
                 item.status === "error" ? item.error : "Ready"}
              </div>
            </div>
          ))}
          {!items.length ? <div className={styles.empty}>Add audio files above to create an MP3 conversion queue.</div> : null}
        </div>
      </section>
      <MobileNav />
    </main>
  );
}