import { useEffect, useRef } from 'react';
import { useLayerStore } from '@/store';
import { toast } from '@/lib/toast-utils';

const AUTO_SAVE_KEY = 'paint-ui-autosave';
const AUTO_SAVE_INTERVAL = 30000; // 30 seconds

interface AutoSaveData {
  timestamp: number;
  layers: any[];
}

/**
 * Auto-save hook - saves project to localStorage periodically
 */
export function useAutoSave() {
  const { layers } = useLayerStore();
  const lastSaveRef = useRef<number>(0);
  const saveTimeoutRef = useRef<NodeJS.Timeout | null>(null);

  // Save project to localStorage
  const saveProject = () => {
    try {
      const saveData: AutoSaveData = {
        timestamp: Date.now(),
        layers: layers.map((layer) => ({
          ...layer,
          canvas: layer.canvas ? layer.canvas.toDataURL() : null,
          mask: layer.mask?.canvas ? {
            ...layer.mask,
            canvas: layer.mask.canvas.toDataURL(),
          } : null,
        })),
      };

      localStorage.setItem(AUTO_SAVE_KEY, JSON.stringify(saveData));
      lastSaveRef.current = Date.now();
    } catch (error) {
      console.error('Auto-save failed:', error);
    }
  };

  // Auto-save on interval
  useEffect(() => {
    if (layers.length === 0) return;

    // Clear existing timeout
    if (saveTimeoutRef.current) {
      clearTimeout(saveTimeoutRef.current);
    }

    // Schedule next save
    saveTimeoutRef.current = setTimeout(() => {
      saveProject();
    }, AUTO_SAVE_INTERVAL);

    return () => {
      if (saveTimeoutRef.current) {
        clearTimeout(saveTimeoutRef.current);
      }
    };
  }, [layers]);

  return {
    saveProject,
    lastSave: lastSaveRef.current,
  };
}

/**
 * Check if auto-saved project exists
 */
export function hasAutoSave(): boolean {
  if (typeof window === 'undefined') return false;
  return localStorage.getItem(AUTO_SAVE_KEY) !== null;
}

/**
 * Load auto-saved project
 */
export async function loadAutoSave(): Promise<boolean> {
  try {
    const saved = localStorage.getItem(AUTO_SAVE_KEY);
    if (!saved) return false;

    const data: AutoSaveData = JSON.parse(saved);
    const { clearLayers, createLayer } = useLayerStore.getState();

    // Clear existing layers
    clearLayers();

    // Restore layers
    for (const savedLayer of data.layers) {
      const layer = createLayer({
        name: savedLayer.name,
        width: savedLayer.width,
        height: savedLayer.height,
        x: savedLayer.x,
        y: savedLayer.y,
        opacity: savedLayer.opacity,
        blendMode: savedLayer.blendMode,
      });

      // Restore canvas
      if (savedLayer.canvas && layer.canvas) {
        const img = new Image();
        await new Promise((resolve, reject) => {
          img.onload = resolve;
          img.onerror = reject;
          img.src = savedLayer.canvas;
        });

        const ctx = layer.canvas.getContext('2d');
        if (ctx) {
          ctx.drawImage(img, 0, 0);
        }
      }

      // Restore mask
      if (savedLayer.mask?.canvas) {
        const maskCanvas = document.createElement('canvas');
        maskCanvas.width = savedLayer.width;
        maskCanvas.height = savedLayer.height;

        const maskImg = new Image();
        await new Promise((resolve, reject) => {
          maskImg.onload = resolve;
          maskImg.onerror = reject;
          maskImg.src = savedLayer.mask.canvas;
        });

        const maskCtx = maskCanvas.getContext('2d');
        if (maskCtx) {
          maskCtx.drawImage(maskImg, 0, 0);
        }

        useLayerStore.getState().updateLayer(layer.id, {
          mask: {
            canvas: maskCanvas,
            enabled: savedLayer.mask.enabled,
            inverted: savedLayer.mask.inverted,
          },
        });
      }

      // Restore other properties
      useLayerStore.getState().updateLayer(layer.id, {
        visible: savedLayer.visible,
        locked: savedLayer.locked,
        order: savedLayer.order,
      });
    }

    const date = new Date(data.timestamp);
    toast.success(`Auto-save restored from ${date.toLocaleTimeString()}`);
    return true;
  } catch (error) {
    console.error('Failed to load auto-save:', error);
    toast.error('Failed to restore auto-save');
    return false;
  }
}

/**
 * Clear auto-save
 */
export function clearAutoSave(): void {
  if (typeof window !== 'undefined') {
    localStorage.removeItem(AUTO_SAVE_KEY);
  }
}

/**
 * Get auto-save timestamp
 */
export function getAutoSaveTime(): Date | null {
  if (typeof window === 'undefined') return null;

  const saved = localStorage.getItem(AUTO_SAVE_KEY);
  if (!saved) return null;

  try {
    const data: AutoSaveData = JSON.parse(saved);
    return new Date(data.timestamp);
  } catch {
    return null;
  }
}