import { describe, it, expect } from "vitest";
import { parseShapeString } from "@/samples/slay-the-spire-like/system/utils/parse-shape";
import { IDENTITY_TRANSFORM } from "@/samples/slay-the-spire-like/system/utils/shape-collision";
import {
  createGridInventory,
  placeItem,
  removeItem,
  moveItem,
  rotateItem,
  flipItem,
  getOccupiedCellSet,
  getItemAtCell,
  getAdjacentItems,
  validatePlacement,
  type InventoryItem,
} from "@/samples/slay-the-spire-like/system/grid-inventory";
import { createItemIn } from "@/samples/slay-the-spire-like/system/grid-inventory/factory";
import type {
  GameItem,
  GameItemMeta,
} from "@/samples/slay-the-spire-like/system/grid-inventory/types";
import type {
  CardData,
  ItemData,
} from "@/samples/slay-the-spire-like/system/types";

/**
 * Helper: create a minimal CardData for testing.
 */
function createTestCardData(id: string, name: string, desc: string): CardData {
  return {
    id,
    name,
    desc,
    type: "item",
    costType: "energy",
    costCount: 1,
    targetType: "enemy",
    effects: [],
  };
}

/**
 * Helper: create a minimal ItemData for testing.
 */
function createTestItemData(
  id: string,
  name: string,
  shapeStr: string,
  desc: string,
): ItemData {
  return {
    id,
    type: "weapon",
    name,
    shape: shapeStr,
    card: createTestCardData(id, name, desc),
    price: 10,
    description: desc,
  };
}

/**
 * Helper: create a test inventory item.
 */
function createTestItem(
  id: string,
  shapeStr: string,
  transform = IDENTITY_TRANSFORM,
): InventoryItem<Record<string, never>> {
  const shape = parseShapeString(shapeStr);
  return {
    id,
    shape,
    transform: { ...transform },
  };
}

describe("grid-inventory", () => {
  describe("createGridInventory", () => {
    it("should create an empty inventory with correct dimensions", () => {
      const inv = createGridInventory(6, 4);
      expect(inv.width).toBe(6);
      expect(inv.height).toBe(4);
      expect(inv.items.size).toBe(0);
      expect(inv.occupiedCells.size).toBe(0);
    });
  });

  describe("placeItem", () => {
    it("should place a single-cell item", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "o");
      placeItem(inv, item);

      expect(inv.items.size).toBe(1);
      expect(inv.items.has("sword")).toBe(true);
      expect(inv.occupiedCells.has("0,0")).toBe(true);
    });

    it("should place a multi-cell item", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("axe", "oee");
      placeItem(inv, item);

      expect(inv.items.size).toBe(1);
      expect(inv.occupiedCells.size).toBe(3);
      expect(inv.occupiedCells.has("0,0")).toBe(true);
      expect(inv.occupiedCells.has("1,0")).toBe(true);
      expect(inv.occupiedCells.has("2,0")).toBe(true);
    });

    it("should place multiple items", () => {
      const inv = createGridInventory(6, 4);
      const itemA = createTestItem("a", "o");
      const itemB = createTestItem("b", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 3, y: 0 },
      });
      placeItem(inv, itemA);
      placeItem(inv, itemB);

      expect(inv.items.size).toBe(2);
      expect(inv.occupiedCells.size).toBe(2);
      expect(inv.occupiedCells.has("0,0")).toBe(true);
      expect(inv.occupiedCells.has("3,0")).toBe(true);
    });
  });

  describe("removeItem", () => {
    it("should remove an item and free its cells", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "oee");
      placeItem(inv, item);

      removeItem(inv, "sword");

      expect(inv.items.size).toBe(0);
      expect(inv.occupiedCells.size).toBe(0);
    });

    it("should only free the removed item's cells", () => {
      const inv = createGridInventory(6, 4);
      const itemA = createTestItem("a", "o");
      const itemB = createTestItem("b", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 0 },
      });
      placeItem(inv, itemA);
      placeItem(inv, itemB);

      removeItem(inv, "a");

      expect(inv.items.size).toBe(1);
      expect(inv.occupiedCells.size).toBe(1);
      expect(inv.occupiedCells.has("0,0")).toBe(false);
      expect(inv.occupiedCells.has("2,0")).toBe(true);
    });

    it("should do nothing for non-existent item", () => {
      const inv = createGridInventory(6, 4);
      removeItem(inv, "nonexistent");
      expect(inv.items.size).toBe(0);
    });
  });

  describe("validatePlacement", () => {
    it("should return valid for empty board", () => {
      const inv = createGridInventory(6, 4);
      const shape = parseShapeString("o");
      const result = validatePlacement(inv, shape, IDENTITY_TRANSFORM);
      expect(result).toEqual({ valid: true });
    });

    it("should return invalid for out of bounds", () => {
      const inv = createGridInventory(6, 4);
      const shape = parseShapeString("o");
      const result = validatePlacement(inv, shape, {
        ...IDENTITY_TRANSFORM,
        offset: { x: 6, y: 0 },
      });
      expect(result).toEqual({ valid: false, reason: "超出边界" });
    });

    it("should return invalid for collision with existing item", () => {
      const inv = createGridInventory(6, 4);
      const existing = createTestItem("a", "oee");
      placeItem(inv, existing);

      const shape = parseShapeString("o");
      const result = validatePlacement(inv, shape, IDENTITY_TRANSFORM);
      expect(result).toEqual({ valid: false, reason: "与已有物品重叠" });
    });

    it("should return valid when there is room nearby", () => {
      const inv = createGridInventory(6, 4);
      const existing = createTestItem("a", "o");
      placeItem(inv, existing);

      const shape = parseShapeString("o");
      const result = validatePlacement(inv, shape, {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: 0 },
      });
      expect(result).toEqual({ valid: true });
    });
  });

  describe("moveItem", () => {
    it("should move item to a new position", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "o");
      placeItem(inv, item);

      const result = moveItem(inv, "sword", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 5, y: 3 },
      });

      expect(result).toEqual({ success: true });
      expect(inv.occupiedCells.has("0,0")).toBe(false);
      expect(inv.occupiedCells.has("5,3")).toBe(true);
      expect(item.transform.offset).toEqual({ x: 5, y: 3 });
    });

    it("should reject move that goes out of bounds", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "o");
      placeItem(inv, item);

      const result = moveItem(inv, "sword", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 6, y: 0 },
      });

      expect(result).toEqual({ success: false, reason: "超出边界" });
      expect(inv.occupiedCells.has("0,0")).toBe(true);
      expect(item.transform.offset).toEqual({ x: 0, y: 0 });
    });

    it("should reject move that collides with another item", () => {
      const inv = createGridInventory(6, 4);
      const itemA = createTestItem("a", "o");
      const itemB = createTestItem("b", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 0 },
      });
      placeItem(inv, itemA);
      placeItem(inv, itemB);

      const result = moveItem(inv, "b", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: 0 },
      });

      expect(result).toEqual({ success: false, reason: "与已有物品重叠" });
      expect(inv.occupiedCells.has("2,0")).toBe(true);
    });

    it("should return error for non-existent item", () => {
      const inv = createGridInventory(6, 4);
      const result = moveItem(inv, "ghost", IDENTITY_TRANSFORM);
      expect(result).toEqual({ success: false, reason: "物品不存在" });
    });

    it("should move multi-cell item correctly", () => {
      const inv = createGridInventory(6, 4);
      // oes: cells at (0,0), (1,0), (1,1)
      const item = createTestItem("axe", "oes");
      placeItem(inv, item);

      const newTransform = { ...IDENTITY_TRANSFORM, offset: { x: 3, y: 1 } };
      moveItem(inv, "axe", newTransform);

      // Old cells should be freed
      expect(inv.occupiedCells.has("0,0")).toBe(false);
      expect(inv.occupiedCells.has("1,0")).toBe(false);
      expect(inv.occupiedCells.has("1,1")).toBe(false);
      // New cells: (0,0)+offset(3,1)=(3,1), (1,0)+(3,1)=(4,1), (1,1)+(3,1)=(4,2)
      expect(inv.occupiedCells.has("3,1")).toBe(true);
      expect(inv.occupiedCells.has("4,1")).toBe(true);
      expect(inv.occupiedCells.has("4,2")).toBe(true);
    });
  });

  describe("rotateItem", () => {
    it("should rotate item by 90 degrees", () => {
      const inv = createGridInventory(6, 4);
      // Horizontal line: (0,0), (1,0)
      const item = createTestItem("bar", "oe", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: 1 }, // Place away from edge so rotation stays in bounds
      });
      placeItem(inv, item);

      const result = rotateItem(inv, "bar", 90);

      expect(result).toEqual({ success: true });
      expect(item.transform.rotation).toBe(90);
    });

    it("should reject rotation that goes out of bounds", () => {
      const inv = createGridInventory(3, 3);
      // Item at the edge: place a 2-wide item at x=1
      const item = createTestItem("bar", "oe", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: 0 },
      });
      placeItem(inv, item);

      // Rotating 90° would make it vertical starting at (1,0), going to (1,-1) -> out of bounds
      const result = rotateItem(inv, "bar", 90);

      expect(result).toEqual({ success: false, reason: "超出边界" });
    });

    it("should reject rotation that collides", () => {
      const inv = createGridInventory(4, 4);
      const itemA = createTestItem("a", "o");
      const itemB = createTestItem("b", "oe", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 0 },
      });
      placeItem(inv, itemA);
      placeItem(inv, itemB);

      // Rotating b 90° would place cells at (2,0) and (2,-1) -> (2,-1) is out of bounds
      // Let's try a different scenario: rotate b 270° -> (2,0) and (2,1) which is fine
      // But rotating to collide with a at (0,0)... need item close to a
      const itemC = createTestItem("c", "os", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: 0 },
      });
      placeItem(inv, itemC);

      // Rotating c 90° would give cells at (1,0) and (0,0) -> collision with a
      const result = rotateItem(inv, "c", 90);
      expect(result).toEqual({ success: false, reason: "与已有物品重叠" });
    });

    it("should return error for non-existent item", () => {
      const inv = createGridInventory(6, 4);
      const result = rotateItem(inv, "ghost", 90);
      expect(result).toEqual({ success: false, reason: "物品不存在" });
    });
  });

  describe("flipItem", () => {
    it("should flip item horizontally", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("bar", "oe");
      placeItem(inv, item);

      const result = flipItem(inv, "bar", "x");

      expect(result).toEqual({ success: true });
      expect(item.transform.flipX).toBe(true);
    });

    it("should flip item vertically", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("bar", "os");
      placeItem(inv, item);

      const result = flipItem(inv, "bar", "y");

      expect(result).toEqual({ success: true });
      expect(item.transform.flipY).toBe(true);
    });

    it("should reject flip that causes collision", () => {
      // oes local cells: (0,0),(1,0),(1,1). flipY: (0,1),(1,1),(1,0).
      // Place flipper at offset (0,2): world cells (0,2),(1,2),(1,3).
      // flipY gives local (0,1),(1,1),(1,0) + offset(0,2) = (0,3),(1,3),(1,2) — same cells rearranged.
      // Need asymmetric shape where flip changes world position.
      // Use oes at offset (0,0): cells (0,0),(1,0),(1,1). flipY: (0,1),(1,1),(1,0).
      // Place blocker at (0,1) — which is NOT occupied by oes initially.
      const inv = createGridInventory(4, 4);
      const blocker = createTestItem("blocker", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: 1 },
      });
      // oes at (0,1): cells (0,1),(1,1),(1,2). This overlaps blocker at (0,1)!
      // Let me try: blocker at (1,0), flipper at offset (0,2).
      // flipper oes at (0,2): (0,2),(1,2),(1,3). blocker at (1,0) — no overlap.
      // flipY: local (0,1),(1,1),(1,0) + offset(0,2) = (0,3),(1,3),(1,2). No collision with (1,0).
      //
      // Simpler: oe shape (width=2, height=1). flipY with height=1 is identity. Use os (width=1, height=2).
      // os: (0,0),(0,1). flipY: (0,1),(0,0) — same cells.
      // Need width>1 and height>1 asymmetric shape: oes
      //
      // Place flipper at (0,0): cells (0,0),(1,0),(1,1). Place blocker at (0,1) — but (0,1) is not occupied.
      // flipY: (0,1),(1,1),(1,0). (0,1) hits blocker!
      const inv2 = createGridInventory(4, 4);
      const blocker2 = createTestItem("blocker", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: 1 },
      });
      const flipper2 = createTestItem("flipper", "oes"); // at (0,0): (0,0),(1,0),(1,1)
      placeItem(inv2, blocker2);
      placeItem(inv2, flipper2);

      const result = flipItem(inv2, "flipper", "y");
      expect(result).toEqual({ success: false, reason: "与已有物品重叠" });
    });

    it("should return error for non-existent item", () => {
      const inv = createGridInventory(6, 4);
      const result = flipItem(inv, "ghost", "x");
      expect(result).toEqual({ success: false, reason: "物品不存在" });
    });
  });

  describe("getOccupiedCellSet", () => {
    it("should return a copy of occupied cells", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("a", "oe");
      placeItem(inv, item);

      const cells = getOccupiedCellSet(inv);
      expect(cells).toEqual(new Set(["0,0", "1,0"]));

      // Mutating the copy should not affect the original
      cells.clear();
      expect(inv.occupiedCells.size).toBe(2);
    });
  });

  describe("getItemAtCell", () => {
    it("should return item at occupied cell", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "oee");
      placeItem(inv, item);

      const found = getItemAtCell(inv, 1, 0);
      expect(found).toBeDefined();
      expect(found!.id).toBe("sword");
    });

    it("should return undefined for empty cell", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("sword", "o");
      placeItem(inv, item);

      const found = getItemAtCell(inv, 5, 5);
      expect(found).toBeUndefined();
    });

    it("should return correct item when multiple items exist", () => {
      const inv = createGridInventory(6, 4);
      const itemA = createTestItem("a", "o");
      const itemB = createTestItem("b", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 3, y: 2 },
      });
      placeItem(inv, itemA);
      placeItem(inv, itemB);

      expect(getItemAtCell(inv, 0, 0)!.id).toBe("a");
      expect(getItemAtCell(inv, 3, 2)!.id).toBe("b");
    });
  });

  describe("getAdjacentItems", () => {
    it("should return orthogonally adjacent items", () => {
      const inv = createGridInventory(6, 4);
      const center = createTestItem("center", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 2 },
      });
      const top = createTestItem("top", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 1 },
      });
      const left = createTestItem("left", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: 2 },
      });
      const right = createTestItem("right", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 3, y: 2 },
      });
      const bottom = createTestItem("bottom", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 2, y: 3 },
      });
      const diagonal = createTestItem("diagonal", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: 1 },
      });

      placeItem(inv, center);
      placeItem(inv, top);
      placeItem(inv, left);
      placeItem(inv, right);
      placeItem(inv, bottom);
      placeItem(inv, diagonal);

      const adj = getAdjacentItems(inv, "center");
      expect(adj.size).toBe(4);
      expect(adj.has("top")).toBe(true);
      expect(adj.has("left")).toBe(true);
      expect(adj.has("right")).toBe(true);
      expect(adj.has("bottom")).toBe(true);
      expect(adj.has("diagonal")).toBe(false);
    });

    it("should return empty for item with no neighbors", () => {
      const inv = createGridInventory(6, 4);
      const item = createTestItem("alone", "o");
      placeItem(inv, item);

      const adj = getAdjacentItems(inv, "alone");
      expect(adj.size).toBe(0);
    });

    it("should return empty for non-existent item", () => {
      const inv = createGridInventory(6, 4);
      const adj = getAdjacentItems(inv, "ghost");
      expect(adj.size).toBe(0);
    });

    it("should handle multi-cell items with multiple adjacencies", () => {
      const inv = createGridInventory(6, 4);
      // Horizontal bar at (0,0)-(1,0)
      const bar = createTestItem("bar", "oe");
      // Item above left cell
      const topA = createTestItem("topA", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: -1 },
      });
      // Item above right cell
      const topB = createTestItem("topB", "o", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 1, y: -1 },
      });

      placeItem(inv, bar);
      placeItem(inv, topA);
      placeItem(inv, topB);

      const adj = getAdjacentItems(inv, "bar");
      expect(adj.size).toBe(2);
      expect(adj.has("topA")).toBe(true);
      expect(adj.has("topB")).toBe(true);
    });
  });

  describe("integration: fill a 4x6 backpack", () => {
    it("should place items fitting a slay-the-spire-like backpack", () => {
      const inv = createGridInventory(4, 6);

      // Sword: 1x3 horizontal at (0,0)
      const sword = createTestItem("sword", "oee");
      // Shield: 2x2 at (0,1)
      const shield = createTestItem("shield", "oes", {
        ...IDENTITY_TRANSFORM,
        offset: { x: 0, y: 1 },
      });

      expect(validatePlacement(inv, sword.shape, sword.transform)).toEqual({
        valid: true,
      });
      placeItem(inv, sword);

      expect(validatePlacement(inv, shield.shape, shield.transform)).toEqual({
        valid: true,
      });
      placeItem(inv, shield);

      expect(inv.items.size).toBe(2);
      expect(inv.occupiedCells.size).toBe(6); // sword(3) + shield(3)

      // Adjacent items should detect each other
      const adjSword = getAdjacentItems(inv, "sword");
      expect(adjSword.has("shield")).toBe(true);

      const adjShield = getAdjacentItems(inv, "shield");
      expect(adjShield.has("sword")).toBe(true);
    });
  });

  describe("createItemIn", () => {
    it("should place item at first valid position", () => {
      const inv = createGridInventory<GameItemMeta>(6, 4);
      const itemData = createTestItemData("sword", "长剑", "oee", "攻击");

      const result = createItemIn(inv, "sword-1", itemData);

      expect(result).toEqual({ success: true });
      expect(inv.items.size).toBe(1);
      expect(inv.occupiedCells.size).toBe(3); // shape "oee" has 3 cells
      expect(inv.items.get("sword-1")?.meta?.itemData.id).toBe("sword");
    });

    it("should skip occupied cells and find next valid position", () => {
      const inv = createGridInventory<GameItemMeta>(6, 4);

      // Place first item manually at origin
      const firstItem = createTestItem(
        "existing",
        "oee",
      ) as unknown as GameItem;
      placeItem(inv, firstItem);

      const itemData = createTestItemData("shield", "盾牌", "o", "防御");

      const result = createItemIn(inv, "shield-1", itemData);

      expect(result).toEqual({ success: true });
      // Shield should be at x=3, y=0 (first available spot after "oee" at x=0-2)
      const placedItem = inv.items.get("shield-1");
      expect(placedItem?.transform.offset).toEqual({ x: 3, y: 0 });
    });

    it("should return error when no valid placement exists", () => {
      const inv = createGridInventory<GameItemMeta>(3, 3);

      // Fill the grid completely with 1x1 items
      for (let i = 0; i < 9; i++) {
        const itemData = createTestItemData(`item${i}`, `物品${i}`, "o", "");
        createItemIn(inv, `item-${i}`, itemData);
      }

      // Try to place one more item
      const itemData = createTestItemData("overflow", "溢出", "oee", "");
      const result = createItemIn(inv, "overflow-1", itemData);

      expect(result).toEqual({ success: false, reason: "无可用位置" });
    });

    it("should handle multi-cell items correctly", () => {
      const inv = createGridInventory<GameItemMeta>(4, 4);
      const itemData = createTestItemData("lshape", "L形", "oes", "特殊");

      const result = createItemIn(inv, "lshape-1", itemData);

      expect(result).toEqual({ success: true });
      expect(inv.items.size).toBe(1);
      // Shape "oes" has 3 cells
      expect(inv.occupiedCells.size).toBe(3);
    });

    it("should not place item when inventory is completely full", () => {
      const inv = createGridInventory<GameItemMeta>(2, 2);

      // Fill with 1x1 items
      const itemData = createTestItemData("small", "小物品", "o", "");
      createItemIn(inv, "small-1", itemData);
      createItemIn(inv, "small-2", itemData);
      createItemIn(inv, "small-3", itemData);
      createItemIn(inv, "small-4", itemData);

      // Grid is now full
      const overflowItem = createTestItemData("overflow", "溢出", "o", "");
      const result = createItemIn(inv, "overflow-5", overflowItem);

      expect(result).toEqual({ success: false, reason: "无可用位置" });
      expect(inv.items.size).toBe(4);
    });
  });
});