import Phaser from 'phaser';
import { MutableSignal } from 'boardgame-core';
import {
  type GridInventory,
  type InventoryItem,
  type GameItemMeta,
  type RunState,
  type CellKey,
  validatePlacement,
  removeItemFromGrid,
  placeItem,
  moveItem,
  rotateItem,
  transformShape,
} from 'boardgame-core/samples/slay-the-spire-like';

const ITEM_COLORS = [0x3388ff, 0xff8833, 0x33ff88, 0xff3388, 0x8833ff, 0x33ffff, 0xffff33, 0xff6633];

export interface InventoryWidgetOptions {
  scene: Phaser.Scene;
  gameState: MutableSignal<RunState>;
  x: number;
  y: number;
  cellSize: number;
  gridGap?: number;
  isLocked?: boolean;
}

interface DragState {
  itemId: string;
  itemShape: InventoryItem<GameItemMeta>['shape'];
  itemTransform: InventoryItem<GameItemMeta>['transform'];
  itemMeta: InventoryItem<GameItemMeta>['meta'];
  ghostContainer: Phaser.GameObjects.Container;
  previewGraphics: Phaser.GameObjects.Graphics;
}

interface LostItem {
  id: string;
  container: Phaser.GameObjects.Container;
}

export class InventoryWidget {
  private scene: Phaser.Scene;
  private gameState: MutableSignal<RunState>;
  private container: Phaser.GameObjects.Container;
  private cellSize: number;
  private gridGap: number;
  private gridX = 0;
  private gridY = 0;
  private isLocked: boolean;

  private itemContainers = new Map<string, Phaser.GameObjects.Container>();
  private itemGraphics = new Map<string, Phaser.GameObjects.Graphics>();
  private itemTexts = new Map<string, Phaser.GameObjects.Text>();
  private colorMap = new Map<string, number>();
  private colorIdx = 0;

  private gridGraphics!: Phaser.GameObjects.Graphics;
  private dragState: DragState | null = null;
  private lostItems = new Map<string, LostItem>();

  private pointerMoveHandler: (pointer: Phaser.Input.Pointer) => void;
  private pointerUpHandler: (pointer: Phaser.Input.Pointer) => void;

  constructor(options: InventoryWidgetOptions) {
    this.scene = options.scene;
    this.gameState = options.gameState;
    this.cellSize = options.cellSize;
    this.gridGap = options.gridGap ?? 2;
    this.isLocked = options.isLocked ?? false;

    const inventory = this.gameState.value.inventory;
    const gridW = inventory.width * this.cellSize + (inventory.width - 1) * this.gridGap;
    const gridH = inventory.height * this.cellSize + (inventory.height - 1) * this.gridGap;

    this.container = this.scene.add.container(options.x, options.y);

    this.drawGridBackground(inventory.width, inventory.height, gridW, gridH);
    this.drawItems();
    this.setupInput();

    this.pointerMoveHandler = this.onPointerMove.bind(this);
    this.pointerUpHandler = this.onPointerUp.bind(this);

    this.scene.events.once('shutdown', () => this.destroy());
  }

  private getInventory(): GridInventory<GameItemMeta> {
    return this.gameState.value.inventory as unknown as GridInventory<GameItemMeta>;
  }

  private drawGridBackground(width: number, height: number, gridW: number, gridH: number): void {
    this.gridGraphics = this.scene.add.graphics();

    for (let y = 0; y < height; y++) {
      for (let x = 0; x < width; x++) {
        const px = this.gridX + x * (this.cellSize + this.gridGap);
        const py = this.gridY + y * (this.cellSize + this.gridGap);

        this.gridGraphics.fillStyle(0x1a1a2e);
        this.gridGraphics.fillRect(px, py, this.cellSize, this.cellSize);
        this.gridGraphics.lineStyle(2, 0x444477);
        this.gridGraphics.strokeRect(px, py, this.cellSize, this.cellSize);
      }
    }

    this.container.add(this.gridGraphics);
  }

  private drawItems(): void {
    const inventory = this.getInventory();

    for (const [itemId, item] of inventory.items) {
      if (this.itemContainers.has(itemId)) continue;
      this.createItemVisuals(itemId, item);
    }
  }

  private createItemVisuals(itemId: string, item: InventoryItem<GameItemMeta>): void {
    const color = this.colorMap.get(itemId) ?? ITEM_COLORS[this.colorIdx++ % ITEM_COLORS.length];
    this.colorMap.set(itemId, color);

    const graphics = this.scene.add.graphics();
    this.itemGraphics.set(itemId, graphics);

    const cells = this.getItemCells(item);
    for (const cell of cells) {
      const px = this.gridX + cell.x * (this.cellSize + this.gridGap);
      const py = this.gridY + cell.y * (this.cellSize + this.gridGap);

      graphics.fillStyle(color);
      graphics.fillRect(px + 1, py + 1, this.cellSize - 2, this.cellSize - 2);
      graphics.lineStyle(2, 0xffffff);
      graphics.strokeRect(px, py, this.cellSize, this.cellSize);
    }

    const firstCell = cells[0];
    const name = item.meta?.itemData.name ?? item.id;
    const fontSize = Math.max(10, Math.floor(this.cellSize / 5));
    const text = this.scene.add.text(
      this.gridX + firstCell.x * (this.cellSize + this.gridGap) + this.cellSize / 2,
      this.gridY + firstCell.y * (this.cellSize + this.gridGap) + this.cellSize / 2,
      name,
      { fontSize: `${fontSize}px`, color: '#fff', fontStyle: 'bold' }
    ).setOrigin(0.5);
    this.itemTexts.set(itemId, text);

    const hitRect = new Phaser.Geom.Rectangle(
      this.gridX + firstCell.x * (this.cellSize + this.gridGap),
      this.gridY + firstCell.y * (this.cellSize + this.gridGap),
      this.cellSize, this.cellSize
    );

    const container = this.scene.add.container(0, 0);
    container.add(graphics);
    container.add(text);
    container.setInteractive(hitRect, Phaser.Geom.Rectangle.Contains);

    container.on('pointerdown', (pointer: Phaser.Input.Pointer) => {
      if (this.isLocked) return;
      if (this.dragState) return;
      if (pointer.button === 0) {
        this.startDrag(itemId, pointer);
      }
    });

    this.itemContainers.set(itemId, container);
    this.container.add(container);
  }

  private getItemCells(item: InventoryItem<GameItemMeta>): { x: number; y: number }[] {
    const cells: { x: number; y: number }[] = [];
    const { offset } = item.transform;
    for (let y = 0; y < item.shape.height; y++) {
      for (let x = 0; x < item.shape.width; x++) {
        if (item.shape.grid[y]?.[x]) {
          cells.push({ x: x + offset.x, y: y + offset.y });
        }
      }
    }
    return cells;
  }

  private setupInput(): void {
    this.scene.input.on('pointermove', this.pointerMoveHandler);
    this.scene.input.on('pointerup', this.pointerUpHandler);
    this.scene.input.on('pointerdown', this.onPointerDown.bind(this));
  }

  private onPointerDown(pointer: Phaser.Input.Pointer): void {
    if (!this.dragState) return;
    if (pointer.button === 1) {
      this.rotateDraggedItem();
    }
  }

  private startDrag(itemId: string, pointer: Phaser.Input.Pointer): void {
    const inventory = this.getInventory();
    const item = inventory.items.get(itemId);
    if (!item) return;

    this.gameState.produce(state => {
      removeItemFromGrid(state.inventory, itemId);
    });
    this.removeItemVisuals(itemId);

    const ghostContainer = this.scene.add.container(pointer.x, pointer.y).setDepth(1000);
    const ghostGraphics = this.scene.add.graphics();
    const color = this.colorMap.get(itemId) ?? 0x888888;

    for (let y = 0; y < item.shape.height; y++) {
      for (let x = 0; x < item.shape.width; x++) {
        if (item.shape.grid[y]?.[x]) {
          ghostGraphics.fillStyle(color, 0.7);
          ghostGraphics.fillRect(x * (this.cellSize + this.gridGap), y * (this.cellSize + this.gridGap), this.cellSize - 2, this.cellSize - 2);
          ghostGraphics.lineStyle(2, 0xffffff);
          ghostGraphics.strokeRect(x * (this.cellSize + this.gridGap), y * (this.cellSize + this.gridGap), this.cellSize, this.cellSize);
        }
      }
    }
    ghostContainer.add(ghostGraphics);

    const previewGraphics = this.scene.add.graphics().setDepth(999).setAlpha(0.5);

    this.dragState = {
      itemId,
      itemShape: item.shape,
      itemTransform: { ...item.transform, offset: { ...item.transform.offset } },
      itemMeta: item.meta,
      ghostContainer,
      previewGraphics,
    };
  }

  private rotateDraggedItem(): void {
    if (!this.dragState) return;

    const currentRotation = (this.dragState.itemTransform.rotation + 90) % 360;
    this.dragState.itemTransform = {
      ...this.dragState.itemTransform,
      rotation: currentRotation,
    };

    this.updateGhostVisuals();
  }

  private updateGhostVisuals(): void {
    if (!this.dragState) return;

    this.dragState.ghostContainer.removeAll(true);
    const ghostGraphics = this.scene.add.graphics();
    const color = this.colorMap.get(this.dragState.itemId) ?? 0x888888;

    const cells = transformShape(this.dragState.itemShape, this.dragState.itemTransform);
    for (const cell of cells) {
      ghostGraphics.fillStyle(color, 0.7);
      ghostGraphics.fillRect(cell.x * (this.cellSize + this.gridGap), cell.y * (this.cellSize + this.gridGap), this.cellSize - 2, this.cellSize - 2);
      ghostGraphics.lineStyle(2, 0xffffff);
      ghostGraphics.strokeRect(cell.x * (this.cellSize + this.gridGap), cell.y * (this.cellSize + this.gridGap), this.cellSize, this.cellSize);
    }
    this.dragState.ghostContainer.add(ghostGraphics);
  }

  private onPointerMove(pointer: Phaser.Input.Pointer): void {
    if (!this.dragState) return;

    this.dragState.ghostContainer.setPosition(pointer.x, pointer.y);

    const gridCell = this.getWorldGridCell(pointer.x, pointer.y);
    this.dragState.previewGraphics.clear();

    if (gridCell) {
      const inventory = this.getInventory();
      const testTransform = { ...this.dragState.itemTransform, offset: { x: gridCell.x, y: gridCell.y } };
      const validation = validatePlacement(inventory, this.dragState.itemShape, testTransform);

      const cells = transformShape(this.dragState.itemShape, testTransform);
      for (const cell of cells) {
        const px = this.gridX + cell.x * (this.cellSize + this.gridGap);
        const py = this.gridY + cell.y * (this.cellSize + this.gridGap);

        if (validation.valid) {
          this.dragState.previewGraphics.fillStyle(0x33ff33, 0.3);
          this.dragState.previewGraphics.fillRect(px, py, this.cellSize, this.cellSize);
          this.dragState.previewGraphics.lineStyle(2, 0x33ff33);
          this.dragState.previewGraphics.strokeRect(px, py, this.cellSize, this.cellSize);
        } else {
          this.dragState.previewGraphics.fillStyle(0xff3333, 0.3);
          this.dragState.previewGraphics.fillRect(px, py, this.cellSize, this.cellSize);
          this.dragState.previewGraphics.lineStyle(2, 0xff3333);
          this.dragState.previewGraphics.strokeRect(px, py, this.cellSize, this.cellSize);
        }
      }
    }
  }

  private onPointerUp(pointer: Phaser.Input.Pointer): void {
    if (!this.dragState) return;

    const gridCell = this.getWorldGridCell(pointer.x, pointer.y);
    const inventory = this.getInventory();

    this.dragState.ghostContainer.destroy();
    this.dragState.previewGraphics.destroy();

    if (gridCell) {
      const testTransform = { ...this.dragState.itemTransform, offset: { x: gridCell.x, y: gridCell.y } };
      const validation = validatePlacement(inventory, this.dragState.itemShape, testTransform);

      if (validation.valid) {
        this.gameState.produce(state => {
          const item: InventoryItem<GameItemMeta> = {
            id: this.dragState!.itemId,
            shape: this.dragState!.itemShape,
            transform: testTransform,
            meta: this.dragState!.itemMeta,
          };
          placeItem(state.inventory, item);
        });
        this.createItemVisualsFromDrag();
      } else {
        this.createLostItem();
      }
    } else {
      this.createLostItem();
    }

    this.dragState = null;
  }

  private createItemVisualsFromDrag(): void {
    if (!this.dragState) return;
    const inventory = this.getInventory();
    const item = inventory.items.get(this.dragState.itemId);
    if (item) {
      this.createItemVisuals(this.dragState.itemId, item);
    }
  }

  private getWorldGridCell(worldX: number, worldY: number): { x: number; y: number } | null {
    const localX = worldX - this.container.x - this.gridX;
    const localY = worldY - this.container.y - this.gridY;

    const cellX = Math.floor(localX / (this.cellSize + this.gridGap));
    const cellY = Math.floor(localY / (this.cellSize + this.gridGap));

    return { x: cellX, y: cellY };
  }

  private createLostItem(): void {
    if (!this.dragState) return;

    const container = this.scene.add.container(
      this.dragState.ghostContainer.x,
      this.dragState.ghostContainer.y
    ).setDepth(500);

    const graphics = this.scene.add.graphics();
    const color = this.colorMap.get(this.dragState.itemId) ?? 0x888888;

    const cells = transformShape(this.dragState.itemShape, this.dragState.itemTransform);
    for (const cell of cells) {
      graphics.fillStyle(color, 0.5);
      graphics.fillRect(cell.x * (this.cellSize + this.gridGap), cell.y * (this.cellSize + this.gridGap), this.cellSize - 2, this.cellSize - 2);
      graphics.lineStyle(2, 0xff4444);
      graphics.strokeRect(cell.x * (this.cellSize + this.gridGap), cell.y * (this.cellSize + this.gridGap), this.cellSize, this.cellSize);
    }
    container.add(graphics);

    const name = this.dragState.itemMeta?.itemData.name ?? this.dragState.itemId;
    const text = this.scene.add.text(0, -20, `${name} (lost)`, {
      fontSize: '12px',
      color: '#ff4444',
      fontStyle: 'italic',
    }).setOrigin(0.5);
    container.add(text);

    this.lostItems.set(this.dragState.itemId, { id: this.dragState.itemId, container });
  }

  private removeItemVisuals(itemId: string): void {
    this.itemContainers.get(itemId)?.destroy();
    this.itemGraphics.get(itemId)?.destroy();
    this.itemTexts.get(itemId)?.destroy();
    this.itemContainers.delete(itemId);
    this.itemGraphics.delete(itemId);
    this.itemTexts.delete(itemId);
  }

  public setLocked(locked: boolean): void {
    this.isLocked = locked;
  }

  public getLostItems(): string[] {
    return Array.from(this.lostItems.keys());
  }

  public clearLostItems(): void {
    for (const lost of this.lostItems.values()) {
      lost.container.destroy();
    }
    this.lostItems.clear();
  }

  public refresh(): void {
    const inventory = this.getInventory();

    for (const itemId of this.itemContainers.keys()) {
      if (!inventory.items.has(itemId)) {
        this.removeItemVisuals(itemId);
      }
    }

    for (const [itemId, item] of inventory.items) {
      if (!this.itemContainers.has(itemId)) {
        this.createItemVisuals(itemId, item);
      }
    }
  }

  public destroy(): void {
    this.scene.input.off('pointermove', this.pointerMoveHandler);
    this.scene.input.off('pointerup', this.pointerUpHandler);

    if (this.dragState) {
      this.dragState.ghostContainer.destroy();
      this.dragState.previewGraphics.destroy();
      this.dragState = null;
    }

    this.clearLostItems();

    for (const container of this.itemContainers.values()) {
      container.destroy();
    }
    this.itemContainers.clear();
    this.itemGraphics.clear();
    this.itemTexts.clear();

    this.gridGraphics.destroy();
    this.container.destroy();
  }
}