import { beforeEach, describe, expect, it, vi } from "vitest";
import { ChaseGameModel } from "../../src/game/chase/model";
import type { Difficulty, GameGraph } from "../../src/game/chase/types";

const mockedGenerateChaseRound = vi.fn();

vi.mock("../../src/game/chase/generator", () => ({
  generateChaseRound: (...args: unknown[]) => mockedGenerateChaseRound(...args),
}));

function createLineGraph(): GameGraph {
  return {
    nodes: {
      A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
      B: { id: "B", q: 1, r: 0, neighbors: ["A", "C"] },
      C: { id: "C", q: 2, r: 0, neighbors: ["B", "D"] },
      D: { id: "D", q: 3, r: 0, neighbors: ["C"] },
    },
    edgeList: [
      ["A", "B"],
      ["B", "C"],
      ["C", "D"],
    ],
  };
}

function makeRound(seed: number, difficulty: Difficulty) {
  return {
    snapshot: {
      seed,
      difficulty,
      graph: createLineGraph(),
      thiefStartNodeId: "B",
      guardStartNodeId: "D",
      thiefNodeId: "B",
      guardNodeId: "D",
      exitNodeId: "C",
      status: "playing" as const,
    },
    meta: {
      hasEscapePath: true,
      pathLength: 1,
      attemptsUsed: 1,
    },
  };
}

describe("chase game model", () => {
  beforeEach(() => {
    mockedGenerateChaseRound.mockReset();
  });

  it("createWithSeed builds model from generator snapshot contract", () => {
    mockedGenerateChaseRound.mockReturnValue(makeRound(123, "normal"));
    const model = ChaseGameModel.createWithSeed({
      seed: 123,
      difficulty: "normal",
    });

    const state = model.getState();
    expect(state.snapshot.seed).toBe(123);
    expect(state.snapshot.difficulty).toBe("normal");
    expect(state.snapshot.status).toBe("playing");
    expect(state.snapshot.thiefNodeId).toBe("B");
    expect(state.snapshot.guardNodeId).toBe("D");
    expect(state.snapshot.exitNodeId).toBe("C");
    expect(state.turn).toBe(0);
    expect(model.getAvailableMoves()).toEqual(["A", "C"]);
  });

  it("getState returns a defensive deep copy of snapshot", () => {
    mockedGenerateChaseRound.mockReturnValue(makeRound(123, "normal"));
    const model = ChaseGameModel.createWithSeed({ seed: 123, difficulty: "normal" });

    const state = model.getState();
    state.snapshot.thiefNodeId = "A";
    state.snapshot.graph.nodes.B.neighbors.push("D");
    state.snapshot.graph.edgeList.push(["A", "D"]);

    const afterMutation = model.getState();
    expect(afterMutation.snapshot.thiefNodeId).toBe("B");
    expect(afterMutation.snapshot.graph.nodes.B.neighbors).toEqual(["A", "C"]);
    expect(afterMutation.snapshot.graph.edgeList).toEqual([
      ["A", "B"],
      ["B", "C"],
      ["C", "D"],
    ]);
  });

  it("thief move to exit wins and increments winCount", () => {
    mockedGenerateChaseRound.mockReturnValue(makeRound(11, "normal"));
    const model = ChaseGameModel.createWithSeed({ seed: 11, difficulty: "normal" });

    model.moveThief("C");
    const state = model.getState();
    expect(state.snapshot.status).toBe("win");
    expect(state.winCount).toBe(1);
    expect(state.snapshot.thiefNodeId).toBe("C");
    expect(state.turn).toBe(1);
  });

  it("guard moves after thief and can cause lose by capture", () => {
    mockedGenerateChaseRound.mockReturnValue({
      ...makeRound(22, "hard"),
      snapshot: {
        ...makeRound(22, "hard").snapshot,
        thiefStartNodeId: "A",
        thiefNodeId: "A",
        exitNodeId: "D",
        guardStartNodeId: "C",
        guardNodeId: "C",
      },
    });

    const model = ChaseGameModel.createWithSeed({ seed: 22, difficulty: "hard" });
    model.moveThief("B");

    const state = model.getState();
    expect(state.snapshot.guardNodeId).toBe("B");
    expect(state.snapshot.thiefNodeId).toBe("B");
    expect(state.snapshot.status).toBe("lose");
    expect(state.turn).toBe(1);
  });

  it("loses when thief has no legal move after guard turn", () => {
    mockedGenerateChaseRound.mockReturnValue({
      snapshot: {
        seed: 33,
        difficulty: "normal" as const,
        graph: {
          nodes: {
            A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
            B: { id: "B", q: 1, r: 0, neighbors: ["A", "C"] },
            C: { id: "C", q: 2, r: 0, neighbors: ["B"] },
          },
          edgeList: [
            ["A", "B"],
            ["B", "C"],
          ],
        },
        thiefStartNodeId: "A",
        guardStartNodeId: "C",
        thiefNodeId: "A",
        guardNodeId: "C",
        exitNodeId: "C",
        status: "playing" as const,
      },
      meta: { hasEscapePath: true, pathLength: 2, attemptsUsed: 1 },
    });

    const model = ChaseGameModel.createWithSeed({ seed: 33, difficulty: "normal" });
    model.moveThief("B");
    const state = model.getState();
    expect(state.snapshot.status).toBe("lose");
    expect(model.getAvailableMoves()).toEqual([]);
    expect(state.turn).toBe(1);
  });

  it("retryRound restores the same initial round snapshot and keeps winCount", () => {
    mockedGenerateChaseRound.mockReturnValueOnce(makeRound(44, "easy"));

    const model = ChaseGameModel.createWithSeed({ seed: 44, difficulty: "easy" });
    const initialState = model.getState();
    model.moveThief("C");
    expect(model.getState().winCount).toBe(1);

    model.retryRound();
    const state = model.getState();
    expect(state.snapshot).toEqual(initialState.snapshot);
    expect(state.snapshot.status).toBe("playing");
    expect(state.winCount).toBe(1);
    expect(state.turn).toBe(0);
    expect(mockedGenerateChaseRound).toHaveBeenCalledTimes(1);
  });

  it("newRound switches seed/difficulty and keeps winCount", () => {
    mockedGenerateChaseRound
      .mockReturnValueOnce(makeRound(55, "easy"))
      .mockReturnValueOnce(makeRound(99, "hard"));

    const model = ChaseGameModel.createWithSeed({ seed: 55, difficulty: "easy" });
    model.moveThief("C");
    expect(model.getState().winCount).toBe(1);

    model.newRound(99, "hard");
    const state = model.getState();
    expect(state.snapshot.seed).toBe(99);
    expect(state.snapshot.difficulty).toBe("hard");
    expect(state.snapshot.status).toBe("playing");
    expect(state.winCount).toBe(1);
    expect(state.turn).toBe(0);
  });

  it("newRound applies the exact input seed and difficulty to snapshot", () => {
    mockedGenerateChaseRound
      .mockReturnValueOnce(makeRound(70, "normal"))
      .mockReturnValueOnce(makeRound(2027, "easy"));

    const model = ChaseGameModel.createWithSeed({ seed: 70, difficulty: "normal" });
    model.newRound(2027, "easy");

    const state = model.getState();
    expect(state.snapshot.seed).toBe(2027);
    expect(state.snapshot.difficulty).toBe("easy");
  });

  it("retryRound resets rng so same move sequence is reproducible", () => {
    const easyRound = {
      snapshot: {
        seed: 1,
        difficulty: "easy" as const,
        graph: {
          nodes: {
            A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
            B: { id: "B", q: 1, r: 0, neighbors: ["A", "C", "E"] },
            C: { id: "C", q: 2, r: 0, neighbors: ["B", "D"] },
            D: { id: "D", q: 3, r: 0, neighbors: ["C"] },
            E: { id: "E", q: 1, r: 1, neighbors: ["B"] },
          },
          edgeList: [
            ["A", "B"],
            ["B", "C"],
            ["C", "D"],
            ["B", "E"],
          ],
        },
        thiefStartNodeId: "D",
        guardStartNodeId: "B",
        thiefNodeId: "D",
        guardNodeId: "B",
        exitNodeId: "A",
        status: "playing" as const,
      },
      meta: { hasEscapePath: true, pathLength: 3, attemptsUsed: 1 },
    };
    mockedGenerateChaseRound.mockReturnValue(easyRound);
    const model = ChaseGameModel.createWithSeed({ seed: 1, difficulty: "easy" });

    model.moveThief("C");
    const guardAfterFirstRun = model.getState().snapshot.guardNodeId;

    model.retryRound();
    model.moveThief("C");
    const guardAfterRetry = model.getState().snapshot.guardNodeId;

    expect(guardAfterFirstRun).toBe("A");
    expect(guardAfterRetry).toBe("A");
  });

  it("newRound reseeds rng so guard behavior follows new seed", () => {
    const roundForSeed1 = {
      snapshot: {
        seed: 1,
        difficulty: "easy" as const,
        graph: {
          nodes: {
            A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
            B: { id: "B", q: 1, r: 0, neighbors: ["A", "C", "E"] },
            C: { id: "C", q: 2, r: 0, neighbors: ["B", "D"] },
            D: { id: "D", q: 3, r: 0, neighbors: ["C"] },
            E: { id: "E", q: 1, r: 1, neighbors: ["B"] },
          },
          edgeList: [
            ["A", "B"],
            ["B", "C"],
            ["C", "D"],
            ["B", "E"],
          ],
        },
        thiefStartNodeId: "D",
        guardStartNodeId: "B",
        thiefNodeId: "D",
        guardNodeId: "B",
        exitNodeId: "A",
        status: "playing" as const,
      },
      meta: { hasEscapePath: true, pathLength: 3, attemptsUsed: 1 },
    };
    const roundForSeed12 = {
      ...roundForSeed1,
      snapshot: {
        ...roundForSeed1.snapshot,
        seed: 12,
      },
    };
    mockedGenerateChaseRound
      .mockReturnValueOnce(roundForSeed1)
      .mockReturnValueOnce(roundForSeed12);

    const model = ChaseGameModel.createWithSeed({ seed: 1, difficulty: "easy" });
    model.moveThief("C");
    const guardWithSeed1 = model.getState().snapshot.guardNodeId;

    model.newRound(12, "easy");
    model.moveThief("C");
    const guardWithSeed12 = model.getState().snapshot.guardNodeId;

    expect(guardWithSeed1).toBe("A");
    expect(guardWithSeed12).toBe("C");
  });

  it("guard strategy follows difficulty probability rule", () => {
    const baseRound = {
      snapshot: {
        seed: 77,
        difficulty: "hard" as const,
        graph: {
          nodes: {
            A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
            B: { id: "B", q: 1, r: 0, neighbors: ["A", "C", "E"] },
            C: { id: "C", q: 2, r: 0, neighbors: ["B", "D"] },
            D: { id: "D", q: 3, r: 0, neighbors: ["C"] },
            E: { id: "E", q: 1, r: 1, neighbors: ["B"] },
          },
          edgeList: [
            ["A", "B"],
            ["B", "C"],
            ["C", "D"],
            ["B", "E"],
          ],
        },
        thiefStartNodeId: "D",
        guardStartNodeId: "B",
        thiefNodeId: "D",
        guardNodeId: "B",
        exitNodeId: "A",
        status: "playing" as const,
      },
      meta: { hasEscapePath: true, pathLength: 3, attemptsUsed: 1 },
    };
    mockedGenerateChaseRound.mockReturnValue(baseRound);

    const hardModel = ChaseGameModel.createWithSeed(
      { seed: 77, difficulty: "hard" },
      { random: () => 0.99 },
    );
    hardModel.moveThief("C");
    expect(hardModel.getState().snapshot.guardNodeId).toBe("C");

    mockedGenerateChaseRound.mockReturnValue({
      ...baseRound,
      snapshot: {
        ...baseRound.snapshot,
        difficulty: "easy",
        thiefNodeId: "D",
        guardNodeId: "B",
      },
    });
    const easyModel = ChaseGameModel.createWithSeed(
      { seed: 77, difficulty: "easy" },
      { random: () => 0.95 },
    );
    easyModel.moveThief("C");
    expect(easyModel.getState().snapshot.guardNodeId).toBe("E");
  });

  it("normal difficulty boundary uses shortest at 0.85 and non-shortest above", () => {
    const round = {
      snapshot: {
        seed: 88,
        difficulty: "normal" as const,
        graph: {
          nodes: {
            A: { id: "A", q: 0, r: 0, neighbors: ["B"] },
            B: { id: "B", q: 1, r: 0, neighbors: ["A", "C", "E"] },
            C: { id: "C", q: 2, r: 0, neighbors: ["B", "D"] },
            D: { id: "D", q: 3, r: 0, neighbors: ["C"] },
            E: { id: "E", q: 1, r: 1, neighbors: ["B"] },
          },
          edgeList: [
            ["A", "B"],
            ["B", "C"],
            ["C", "D"],
            ["B", "E"],
          ],
        },
        thiefStartNodeId: "D",
        guardStartNodeId: "B",
        thiefNodeId: "D",
        guardNodeId: "B",
        exitNodeId: "A",
        status: "playing" as const,
      },
      meta: { hasEscapePath: true, pathLength: 3, attemptsUsed: 1 },
    };

    mockedGenerateChaseRound.mockReturnValue(round);
    const atBoundary = ChaseGameModel.createWithSeed(
      { seed: 88, difficulty: "normal" },
      { random: () => 0.85 },
    );
    atBoundary.moveThief("C");
    expect(atBoundary.getState().snapshot.guardNodeId).toBe("C");

    mockedGenerateChaseRound.mockReturnValue(round);
    let call = 0;
    const aboveBoundary = ChaseGameModel.createWithSeed(
      { seed: 88, difficulty: "normal" },
      {
        random: () => {
          call += 1;
          return call === 1 ? 0.8501 : 0.9;
        },
      },
    );
    aboveBoundary.moveThief("C");
    expect(aboveBoundary.getState().snapshot.guardNodeId).toBe("E");
  });
});