import { create } from 'zustand';
import type {
  Selection,
  SelectionType,
  SelectionMode,
  SelectionState,
} from '@/types/selection';

interface SelectionStore extends SelectionState {
  setActiveSelection: (selection: Selection | null) => void;
  setSelectionType: (type: SelectionType) => void;
  setSelectionMode: (mode: SelectionMode) => void;
  setFeather: (feather: number) => void;
  setTolerance: (tolerance: number) => void;
  setMarching: (isMarching: boolean) => void;
  clearSelection: () => void;
  selectAll: () => void;
  invertSelection: () => void;
  expandSelection: (pixels: number) => void;
  contractSelection: (pixels: number) => void;
  featherSelection: (radius: number) => void;
}

export const useSelectionStore = create<SelectionStore>((set) => ({
  activeSelection: null,
  selectionType: 'rectangular',
  selectionMode: 'new',
  feather: 0,
  tolerance: 32,
  isMarching: true,

  setActiveSelection: (selection) =>
    set({
      activeSelection: selection,
    }),

  setSelectionType: (type) =>
    set({
      selectionType: type,
    }),

  setSelectionMode: (mode) =>
    set({
      selectionMode: mode,
    }),

  setFeather: (feather) =>
    set({
      feather: Math.max(0, Math.min(250, feather)),
    }),

  setTolerance: (tolerance) =>
    set({
      tolerance: Math.max(0, Math.min(255, tolerance)),
    }),

  setMarching: (isMarching) =>
    set({
      isMarching,
    }),

  clearSelection: () =>
    set({
      activeSelection: null,
    }),

  selectAll: () =>
    set(() => {
      const { useCanvasStore, useLayerStore } = require('@/store');
      const { width, height } = useCanvasStore.getState();
      const { getActiveLayer } = useLayerStore.getState();
      const activeLayer = getActiveLayer();

      if (!activeLayer) return {};

      // Create a mask that covers the entire canvas
      const maskData = new Uint8Array(width * height).fill(255);

      return {
        activeSelection: {
          id: `selection-${Date.now()}`,
          layerId: activeLayer.id,
          mask: {
            width,
            height,
            data: maskData,
            bounds: {
              x: 0,
              y: 0,
              width,
              height,
            },
          },
          inverted: false,
          feather: 0,
          createdAt: Date.now(),
        },
      };
    }),

  invertSelection: () =>
    set((state) => {
      if (state.activeSelection) {
        return {
          activeSelection: {
            ...state.activeSelection,
            inverted: !state.activeSelection.inverted,
          },
        };
      }
      return state;
    }),

  expandSelection: (pixels) =>
    set((state) => {
      if (!state.activeSelection) return state;

      const { mask } = state.activeSelection;
      const { width, height, data } = mask;
      const newData = new Uint8Array(data.length);

      // Expand selection by dilating the mask
      for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
          const idx = y * width + x;
          let maxValue = data[idx];

          // Check neighbors within radius
          for (let dy = -pixels; dy <= pixels; dy++) {
            for (let dx = -pixels; dx <= pixels; dx++) {
              const nx = x + dx;
              const ny = y + dy;

              if (nx >= 0 && nx < width && ny >= 0 && ny < height) {
                const nidx = ny * width + nx;
                if (data[nidx] > maxValue) {
                  maxValue = data[nidx];
                }
              }
            }
          }

          newData[idx] = maxValue;
        }
      }

      return {
        activeSelection: {
          ...state.activeSelection,
          mask: {
            ...mask,
            data: newData,
          },
        },
      };
    }),

  contractSelection: (pixels) =>
    set((state) => {
      if (!state.activeSelection) return state;

      const { mask } = state.activeSelection;
      const { width, height, data } = mask;
      const newData = new Uint8Array(data.length);

      // Contract selection by eroding the mask
      for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
          const idx = y * width + x;
          let minValue = data[idx];

          // Check neighbors within radius
          for (let dy = -pixels; dy <= pixels; dy++) {
            for (let dx = -pixels; dx <= pixels; dx++) {
              const nx = x + dx;
              const ny = y + dy;

              if (nx >= 0 && nx < width && ny >= 0 && ny < height) {
                const nidx = ny * width + nx;
                if (data[nidx] < minValue) {
                  minValue = data[nidx];
                }
              }
            }
          }

          newData[idx] = minValue;
        }
      }

      return {
        activeSelection: {
          ...state.activeSelection,
          mask: {
            ...mask,
            data: newData,
          },
        },
      };
    }),

  featherSelection: (radius) =>
    set((state) => {
      if (!state.activeSelection) return state;

      const { mask } = state.activeSelection;
      const { width, height, data } = mask;
      const newData = new Uint8Array(data.length);

      // Apply Gaussian blur for feathering
      const sigma = radius / 3;
      const kernelSize = Math.ceil(radius * 2) + 1;
      const kernel: number[] = [];
      let kernelSum = 0;

      // Generate Gaussian kernel
      for (let i = 0; i < kernelSize; i++) {
        const x = i - Math.floor(kernelSize / 2);
        const value = Math.exp(-(x * x) / (2 * sigma * sigma));
        kernel.push(value);
        kernelSum += value;
      }

      // Normalize kernel
      for (let i = 0; i < kernel.length; i++) {
        kernel[i] /= kernelSum;
      }

      // Horizontal pass
      const temp = new Uint8Array(data.length);
      for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
          let sum = 0;
          const halfKernel = Math.floor(kernelSize / 2);

          for (let k = 0; k < kernelSize; k++) {
            const sx = x + k - halfKernel;
            if (sx >= 0 && sx < width) {
              sum += data[y * width + sx] * kernel[k];
            }
          }

          temp[y * width + x] = Math.round(sum);
        }
      }

      // Vertical pass
      for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
          let sum = 0;
          const halfKernel = Math.floor(kernelSize / 2);

          for (let k = 0; k < kernelSize; k++) {
            const sy = y + k - halfKernel;
            if (sy >= 0 && sy < height) {
              sum += temp[sy * width + x] * kernel[k];
            }
          }

          newData[y * width + x] = Math.round(sum);
        }
      }

      return {
        activeSelection: {
          ...state.activeSelection,
          mask: {
            ...mask,
            data: newData,
          },
          feather: radius,
        },
      };
    }),
}));