import { useState, useEffect, useCallback } from "react";
import { toast } from "sonner";
import { ImageFile, ConversionSettings } from "@/types";
import { processImage, generateFinalFilename, downloadDataUrl } from "@/lib/image-processor";

export const initialSettings: ConversionSettings = {
  width: "",
  height: "",
  aspectRatio: "custom",
  keepOrientation: true,
  format: "webp",
  quality: 90,
  prefix: "",
  suffix: "",
  useCounter: false,
  counterStart: 1,
  counterDigits: 3,
  useDefaultBaseName: false,
  defaultBaseName: "",
  scaleMode: 'cover',
  objectPosition: 'center center',
};

export function useImageConverter() {
  const [images, setImages] = useState<ImageFile[]>([]);
  const [settings, setSettings] = useState<ConversionSettings>(initialSettings);
  const [isConverting, setIsConverting] = useState(false);
  const [convertingIndex, setConvertingIndex] = useState<number | null>(null);

  useEffect(() => {
    const urls = images.map(img => img.previewUrl);
    return () => {
      urls.forEach(url => URL.revokeObjectURL(url));
    };
  }, [images]);

  const updateSettings = useCallback((newSettings: Partial<ConversionSettings>) => {
    setSettings(prev => ({ ...prev, ...newSettings }));
  }, []);

  const handleFiles = useCallback((files: FileList | null) => {
    if (!files || files.length === 0) return;

    const imageFiles = Array.from(files).filter(file => file.type.startsWith("image/"));
    if (imageFiles.length === 0) {
      toast.error("Keine gültigen Bilddateien gefunden.");
      return;
    }

    const newImageFiles: ImageFile[] = imageFiles.map(file => ({
      file,
      previewUrl: URL.createObjectURL(file),
      filename: settings.useDefaultBaseName && settings.defaultBaseName
        ? settings.defaultBaseName
        : file.name.substring(0, file.name.lastIndexOf(".")),
    }));

    setImages(prev => [...prev, ...newImageFiles]);
    toast.success(`${imageFiles.length} Bild(er) hinzugefügt.`);
  }, [settings.useDefaultBaseName, settings.defaultBaseName]);

  const handleRemoveImage = useCallback((indexToRemove: number) => {
    setImages(prev => {
      const imageToRemove = prev[indexToRemove];
      if (imageToRemove) {
        URL.revokeObjectURL(imageToRemove.previewUrl);
      }
      return prev.filter((_, i) => i !== indexToRemove);
    });
  }, []);

  const handleClearAll = useCallback(() => {
    setImages([]);
    updateSettings({ width: initialSettings.width, height: initialSettings.height });
    toast.info("Alle Bilder gelöscht.");
  }, [updateSettings]);

  const handleFilenameChange = useCallback((index: number, newName: string) => {
    setImages(prev => {
      const newImages = [...prev];
      if (newImages[index]) {
        newImages[index].filename = newName;
      }
      return newImages;
    });
  }, []);

  const handleConvertAndDownloadSingle = useCallback(async (index: number) => {
    setConvertingIndex(index);
    toast.info(`Starte Konvertierung für ${images[index].filename}...`);
    try {
      const imageToConvert = images[index];
      const dataUrl = await processImage(imageToConvert, settings);
      const finalFilename = generateFinalFilename(imageToConvert.filename, settings, index);
      downloadDataUrl(dataUrl, `${finalFilename}.${settings.format}`);
      toast.success(`${imageToConvert.filename} erfolgreich exportiert!`);
    } catch (error) {
      const message = error instanceof Error ? error.message : "Ein unbekannter Fehler ist aufgetreten.";
      toast.error(message);
    } finally {
      setConvertingIndex(null);
    }
  }, [images, settings]);

  const handleConvertAndDownloadAll = useCallback(async () => {
    if (images.length === 0) {
      toast.error("Bitte laden Sie zuerst Bilder hoch.");
      return;
    }
    setIsConverting(true);
    toast.info(`Starte Konvertierung für ${images.length} Bilder...`);

    const conversionPromises = images.map(async (image, index) => {
      try {
        const dataUrl = await processImage(image, settings);
        const finalFilename = generateFinalFilename(image.filename, settings, index);
        downloadDataUrl(dataUrl, `${finalFilename}.${settings.format}`);
      } catch (error) {
        const message = error instanceof Error ? error.message : `Verarbeitung von ${image.filename} fehlgeschlagen`;
        toast.error(message);
        throw error;
      }
    });

    try {
      await Promise.all(conversionPromises);
      toast.success(`Alle ${images.length} Bilder erfolgreich exportiert!`);
    } catch (error) {
      toast.error("Einige Bilder konnten nicht konvertiert werden. Siehe einzelne Fehler.");
    } finally {
      setIsConverting(false);
    }
  }, [images, settings]);

  const handleResetSettings = useCallback(() => {
    setSettings(initialSettings);
    toast.success("Alle Einstellungen wurden auf ihre Standardwerte zurückgesetzt.");
  }, []);

  const handleAspectRatioChange = useCallback((value: string) => {
    updateSettings({ aspectRatio: value });
    if (value === "custom") return;

    const [w, h] = value.split("/").map(Number);
    let newWidth: number, newHeight: number;
    if (w > h) {
      newWidth = 1000; newHeight = Math.round((1000 * h) / w);
    } else if (h > w) {
      newHeight = 1000; newWidth = Math.round((1000 * w) / h);
    } else {
      newWidth = 1000; newHeight = 1000;
    }
    updateSettings({ width: newWidth, height: newHeight });
  }, [updateSettings]);

  const handleSwapDimensions = useCallback(() => {
    updateSettings({ width: settings.height, height: settings.width });
  }, [settings.height, settings.width, updateSettings]);

  const handleApplyDefaultBaseNameToAll = useCallback(() => {
    if (!settings.defaultBaseName) {
      toast.error("Bitte geben Sie einen Standard-Basisnamen zum Anwenden ein.");
      return;
    }
    if (images.length === 0) {
      toast.info("Laden Sie zuerst einige Bilder hoch.");
      return;
    }
    setImages(prev => prev.map(img => ({ ...img, filename: settings.defaultBaseName })));
    toast.success(`Basisname für alle ${images.length} Bilder auf "${settings.defaultBaseName}" gesetzt.`);
  }, [images.length, settings.defaultBaseName]);

  return {
    images,
    settings,
    isConverting,
    convertingIndex,
    updateSettings,
    handleFiles,
    handleRemoveImage,
    handleClearAll,
    handleFilenameChange,
    handleConvertAndDownloadSingle,
    handleConvertAndDownloadAll,
    handleResetSettings,
    handleAspectRatioChange,
    handleSwapDimensions,
    handleApplyDefaultBaseNameToAll,
  };
}