import { describe, expect, it } from "vitest";
import {
  applyCommand,
  activePlayer,
  createGame,
  boardView,
  gameLos,
  sustainedOn,
  viewFor,
  type Command,
  type GameState,
  type PlayerId,
} from "../src";
import { cellKey, edgeKey, neighbor, SIDES, stepTarget, type Cell, type Side } from "../src/board";
import type { CardInstance } from "../src/cards";

function newGame(seed = 42) {
  return createGame({ playerIds: ["alice", "bob"], seed, sets: ["basic"] });
}

function must(state: GameState, player: PlayerId, command: Command): GameState {
  const result = applyCommand(state, player, command);
  if (!result.ok) throw new Error(`command failed: ${result.error}`);
  return result.state;
}

function giveCard(state: GameState, playerId: PlayerId, cardId: string, tag = "T", slot = 0): CardInstance {
  const p = state.players.find((p) => p.id === playerId)!;
  const instance = { instanceId: `${cardId}#${tag}`, cardId };
  p.hand[slot] = instance;
  return instance;
}

function toRound2(state: GameState): GameState {
  state = must(state, activePlayer(state).id, { type: "endTurn", draw: 0 });
  state = must(state, activePlayer(state).id, { type: "endTurn", draw: 0 });
  return state;
}

function emptyNeighborCell(state: GameState, of: Cell): { cell: Cell; side: Side } {
  const view = boardView(state);
  for (const side of SIDES) {
    const t = stepTarget(view, of, side);
    if (t.kind !== "step") continue;
    const key = cellKey(t.to);
    if (view.homes.some((h) => cellKey(h) === key)) continue;
    if (state.treasures.some((tr) => tr.position && cellKey(tr.position) === key)) continue;
    if (state.players.some((p) => cellKey(p.position) === key)) continue;
    return { cell: t.to, side };
  }
  throw new Error("no empty neighbor");
}

describe("around the corner", () => {
  it("bends line of sight past a wall that blocks a straight cast", () => {
    let { state } = newGame();
    state = toRound2(state);
    const attacker = activePlayer(state);
    const defender = state.players.find((p) => p.id !== attacker.id)!;
    // Find a hidden cell (no direct LOS) that IS reachable with one bend.
    const view = boardView(state);
    let hidden: Cell | null = null;
    outer: for (const key of Object.keys(view.cells)) {
      const [x, y] = key.split(",").map(Number) as [number, number];
      const cell = { x, y };
      if (gameLos(state, attacker.position, cell)) continue;
      for (const midKey of Object.keys(view.cells)) {
        const [mx, my] = midKey.split(",").map(Number) as [number, number];
        const mid = { x: mx, y: my };
        if (gameLos(state, attacker.position, mid) && gameLos(state, mid, cell)) {
          hidden = cell;
          break outer;
        }
      }
    }
    expect(hidden).not.toBeNull();
    defender.position = hidden!;

    const fb = giveCard(state, attacker.id, "fireball", "F", 0);
    giveCard(state, attacker.id, "around-the-corner", "ATC", 1);
    // Straight cast: refused.
    const straight = applyCommand(state, attacker.id, {
      type: "cast", instanceId: fb.instanceId, target: { kind: "player", playerId: defender.id },
    });
    expect(straight.ok).toBe(false);
    // Bent cast: lands.
    state = must(state, attacker.id, {
      type: "cast", instanceId: fb.instanceId, aroundCornerInstanceId: "around-the-corner#ATC",
      target: { kind: "player", playerId: defender.id },
    });
    state = must(state, defender.id, { type: "pass" });
    expect(state.players.find((p) => p.id === defender.id)!.life).toBe(10);
  });
});

describe("blind", () => {
  it("blinded movement lurches in rolled directions and bumps cost movement", () => {
    let { state } = newGame(7);
    state = toRound2(state);
    const attacker = activePlayer(state);
    const defender = state.players.find((p) => p.id !== attacker.id)!;
    defender.position = { ...attacker.position };
    const bl = giveCard(state, attacker.id, "blind");
    giveCard(state, attacker.id, "number-3", "N", 1);
    state = must(state, attacker.id, {
      type: "cast", instanceId: bl.instanceId, numberInstanceIds: ["number-3#N"],
      target: { kind: "player", playerId: defender.id },
    });
    state = must(state, defender.id, { type: "pass" });
    expect(sustainedOn(state, defender.id, "blind").length).toBe(1);
    state = must(state, attacker.id, { type: "endTurn", draw: 0 });

    // Every move consumes exactly one movement point whether it lands or bumps.
    const before = state.turn.movementUsed;
    state = must(state, defender.id, { type: "move", direction: "N" });
    expect(state.turn.movementUsed).toBe(before + 1);
  });

  it("blinded casts fly in a rolled direction and can miss entirely", () => {
    // Across seeds: a blinded caster aiming at a real target sometimes hits
    // (roll matches), usually misses (attack dissipates, card still spent).
    let hits = 0, misses = 0;
    for (let seed = 1; seed <= 10; seed++) {
      let { state } = newGame(seed);
      state = toRound2(state);
      const attacker = activePlayer(state);
      const defender = state.players.find((p) => p.id !== attacker.id)!;
      // Stand the defender one cell east-ish with LOS.
      const spot = emptyNeighborCell(state, attacker.position);
      defender.position = spot.cell;
      state.sustained.push({
        id: "fx-test", cardId: "blind", casterId: defender.id,
        targetId: attacker.id, remainingTurns: 3, data: {},
      });
      const fb = giveCard(state, attacker.id, "fireball", "F", 0);
      const result = applyCommand(state, attacker.id, {
        type: "cast", instanceId: fb.instanceId, target: { kind: "player", playerId: defender.id },
      });
      expect(result.ok).toBe(true);
      if (!result.ok) continue;
      const dLife = result.state.players.find((p) => p.id === defender.id)!;
      if (result.state.stack) {
        hits++; // the roll matched: attack proceeds normally
      } else {
        misses++;
        expect(result.state.turn.attackUsed).toBe(true); // card spent anyway
      }
      void dLife;
    }
    expect(hits + misses).toBe(10);
    expect(misses).toBeGreaterThan(0);
  });
});

describe("ugly", () => {
  it("drives every visible opponent out of line of sight", () => {
    let { state } = newGame();
    const caster = activePlayer(state);
    const opp = state.players.find((p) => p.id !== caster.id)!;
    opp.position = { ...caster.position }; // same square: definitely in LOS
    const ug = giveCard(state, caster.id, "ugly");
    state = must(state, caster.id, { type: "cast", instanceId: ug.instanceId });
    const after = state.players.find((p) => p.id === opp.id)!;
    expect(gameLos(state, state.players.find((p) => p.id === caster.id)!.position, after.position)).toBe(false);
  });
});

describe("illusion wall", () => {
  function setupIllusion(seed = 42) {
    let { state } = newGame(seed);
    const caster = activePlayer(state);
    const spot = emptyNeighborCell(state, caster.position);
    const key = edgeKey(caster.position, spot.side);
    const iw = giveCard(state, caster.id, "illusion-wall");
    state = must(state, caster.id, {
      type: "cast", instanceId: iw.instanceId,
      target: { kind: "edge", cell: caster.position, side: spot.side },
    });
    return { state, caster: caster.id, key, side: spot.side, cell: spot.cell };
  }

  it("the caster walks through their own illusion; others see a wall", () => {
    const { state, caster, key, side } = setupIllusion();
    // Caster's view knows it's fake; the opponent's view shows a wall.
    const casterView = viewFor(state, caster);
    expect(casterView.knownIllusionEdges).toContain(key);
    const other = state.players.find((p) => p.id !== caster)!.id;
    const otherView = viewFor(state, other);
    expect(otherView.board.edges[key]).toBe("wall");
    // And the caster can move through it freely.
    const after = applyCommand(state, caster, { type: "move", direction: side });
    expect(after.ok).toBe(true);
  });

  it("opponents test the illusion when they bump it — some see through, some believe", () => {
    let believed = 0, sawThrough = 0;
    for (let seed = 1; seed <= 12; seed++) {
      const { state, caster, side } = setupIllusion(seed);
      const other = state.players.find((p) => p.id !== caster)!;
      other.position = { ...state.players.find((p) => p.id === caster)!.position };
      let s = must(state, caster, { type: "endTurn", draw: 0 });
      const result = applyCommand(s, other.id, { type: "move", direction: side });
      if (result.ok) sawThrough++;
      else believed++;
    }
    expect(believed + sawThrough).toBe(12);
    expect(believed).toBeGreaterThan(0);
    expect(sawThrough).toBeGreaterThan(0);
  });

  it("dispel creation removes an illusion wall", () => {
    let { state, caster, key, side } = setupIllusion();
    const me = state.players.find((p) => p.id === caster)!;
    const dc = giveCard(state, caster, "dispel-creation", "DC", 1);
    state = must(state, caster, {
      type: "cast", instanceId: dc.instanceId,
      target: { kind: "edge", cell: me.position, side },
    });
    expect(state.illusionWalls[key]).toBeUndefined();
  });
});

describe("sector manipulation", () => {
  it("rotate sector turns walls and pieces together; the home stays centered", () => {
    let { state } = newGame();
    const me = activePlayer(state);
    const idx = state.board.placements.findIndex(
      (p) => me.position.x >= p.origin.x && me.position.x < p.origin.x + 5 &&
             me.position.y >= p.origin.y && me.position.y < p.origin.y + 5,
    );
    const wallsBefore = Object.values(boardView(state).edges).filter((e) => e === "wall").length;
    const homeBefore = { ...me.home };
    const treasuresBefore = state.treasures.filter((t) => t.owner === me.id).map((t) => ({ ...t.position! }));

    const rs = giveCard(state, me.id, "rotate-sector");
    state = must(state, me.id, {
      type: "cast", instanceId: rs.instanceId,
      target: { kind: "cell", cell: me.position }, params: { clockwise: true },
    });
    const after = state.players.find((p) => p.id === me.id)!;
    // Home star is the exact center: rotation cannot move it.
    expect(cellKey(after.home)).toBe(cellKey(homeBefore));
    // The wizard stood on the home (center) at setup? They may have been
    // anywhere; either way they remain inside the same sector.
    const p = state.board.placements[idx]!;
    expect(after.position.x).toBeGreaterThanOrEqual(p.origin.x);
    expect(after.position.x).toBeLessThan(p.origin.x + 5);
    // Wall count is invariant under rotation.
    const wallsAfter = Object.values(boardView(state).edges).filter((e) => e === "wall").length;
    expect(wallsAfter).toBe(wallsBefore);
    // Treasures rotated with the sector (diagonal flips to the other diagonal
    // or stays, but they remain on the board inside the sector).
    for (const t of state.treasures.filter((t) => t.owner === after.id)) {
      expect(state.board.cells[cellKey(t.position!)]).toBe(true);
    }
    void treasuresBefore;
  });

  it("relocate sector slides everything and keeps adjacency", () => {
    let { state } = newGame(); // 2 players: 5x10 column, sectors at y=0 and y=5
    const me = activePlayer(state);
    const idx = state.board.placements.findIndex(
      (p) => me.position.y >= p.origin.y && me.position.y < p.origin.y + 5,
    );
    const myOrigin = state.board.placements[idx]!.origin;
    const otherIdx = idx === 0 ? 1 : 0;
    const otherOrigin = state.board.placements[otherIdx]!.origin;

    // Move my sector to the EAST side of the other sector (still adjacent).
    const dest = { x: otherOrigin.x + 5, y: otherOrigin.y };
    const posBefore = { ...me.position };
    const rel = giveCard(state, me.id, "relocate-sector");
    state = must(state, me.id, {
      type: "cast", instanceId: rel.instanceId,
      target: { kind: "cell", cell: dest }, params: { cell: me.position },
    });
    const after = state.players.find((p) => p.id === me.id)!;
    const dx = dest.x - myOrigin.x, dy = dest.y - myOrigin.y;
    expect(after.position).toEqual({ x: posBefore.x + dx, y: posBefore.y + dy });
    expect(cellKey(after.home)).toBe(cellKey({ x: after.home.x, y: after.home.y }));
    expect(state.board.placements[idx]!.origin).toEqual(dest);
    // The map reassembled: every treasure/wizard cell exists on the new board.
    for (const t of state.treasures) {
      if (t.position) expect(state.board.cells[cellKey(t.position)]).toBe(true);
    }

    // An island move is refused.
    const rel2 = giveCard(state, me.id, "relocate-sector", "R2");
    const refused = applyCommand(state, me.id, {
      type: "cast", instanceId: rel2.instanceId,
      target: { kind: "cell", cell: { x: 40, y: 40 } }, params: { cell: after.position },
    });
    expect(refused.ok).toBe(false);
  });
});