import { readFile } from "node:fs/promises";
import { join } from "node:path";
import { fileURLToPath } from "node:url";
import { mapSchema } from "@nengine/core";
import type { MapDef } from "@nengine/core";
import { parse, stringify } from "yaml";
import { describe, expect, it } from "vitest";
import {
  DEFAULT_ERASE_TILE,
  TILE_SIZE,
  UNKNOWN_TILE_COLOR,
  addTileId,
  canRedo,
  canUndo,
  clearHistory,
  collectTileIds,
  createMapModel,
  erase,
  isWalkableTile,
  markSaved,
  paint,
  pointToTile,
  redo,
  resizeMap,
  serialize,
  setSpawn,
  tileAssetId,
  tileColor,
  toggleWalkable,
  undo,
} from "../src/renderer/map-model.js";
import type { MapModel } from "../src/renderer/map-model.js";

const fixturesDir = fileURLToPath(new URL("./fixtures", import.meta.url));

function grid(width: number, height: number, fill = "grass"): string[][] {
  return Array.from({ length: height }, () => Array.from({ length: width }, () => fill));
}

function makeDef(overrides: Partial<MapDef> = {}): MapDef {
  const def: MapDef = {
    id: "t",
    width: 4,
    height: 4,
    tilesetRef: "ts",
    spawn: { x: 1, y: 1 },
    layers: [{ name: "ground", data: grid(4, 4) }],
    ...overrides,
  };
  return def;
}

function model(def: MapDef): MapModel {
  const m = createMapModel(def);
  if (m === null) throw new Error("expected a valid model");
  return m;
}

describe("createMapModel", () => {
  it("builds a model from a valid def without mutating the input", () => {
    const def = makeDef();
    const snapshot = JSON.stringify(def);
    const m = model(def);
    paint(m, 0, 0, "water");
    setSpawn(m, 2, 2);
    toggleWalkable(m, "grass");
    erase(m, 1, 1);
    expect(JSON.stringify(def)).toBe(snapshot);
    expect(m.dirty).toBe(true);
  });

  it("rejects corrupt defs", () => {
    expect(createMapModel({ id: 42 })).toBeNull();
    const badRows = makeDef({ layers: [{ name: "ground", data: grid(4, 2) }] });
    expect(createMapModel(badRows)).toBeNull();
  });

  it("seeds the palette from ids on the map", () => {
    const def = makeDef({ layers: [{ name: "ground", data: grid(4, 4, "tilled") }] });
    def.layers[0].data[0] = ["water", "grass", "tilled", "grass"];
    const m = model(def);
    expect(m.palette).toEqual(["water", "grass", "tilled"]);
  });
});

describe("paint", () => {
  it("writes ground-layer data and marks dirty", () => {
    const m = model(makeDef());
    expect(m.dirty).toBe(false);
    paint(m, 2, 3, "tilled");
    expect(m.def.layers[0].data[3][2]).toBe("tilled");
    expect(m.dirty).toBe(true);
  });

  it("uses the layer named ground", () => {
    const def = makeDef();
    def.layers = [
      { name: "base", data: grid(4, 4, "rock") },
      { name: "ground", data: grid(4, 4) },
    ];
    const m = model(def);
    paint(m, 1, 1, "water");
    expect(m.def.layers[1].data[1][1]).toBe("water");
    expect(m.def.layers[0].data[1][1]).toBe("rock");
  });

  it("falls back to the first layer when ground is absent", () => {
    const def = makeDef({ layers: [{ name: "base", data: grid(4, 4) }] });
    const m = model(def);
    paint(m, 2, 2, "water");
    expect(m.def.layers[0].data[2][2]).toBe("water");
  });

  it("ignores out-of-bounds cells", () => {
    const m = model(makeDef());
    paint(m, -1, 0, "water");
    paint(m, 0, -1, "water");
    paint(m, 99, 0, "water");
    paint(m, 0, 99, "water");
    expect(m.def.layers[0].data[0][0]).toBe("grass");
    expect(m.dirty).toBe(false);
  });

  it("adds a new tile id to the palette", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "rock");
    expect(m.palette).toContain("rock");
    expect(collectTileIds(m)).toContain("rock");
  });
});

describe("erase", () => {
  it("restores the default grass tile when the map uses it", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    erase(m, 0, 0);
    expect(m.def.layers[0].data[0][0]).toBe(DEFAULT_ERASE_TILE);
  });

  it("falls back to the first palette id when grass is absent", () => {
    const def = makeDef({ layers: [{ name: "ground", data: grid(4, 4, "water") }] });
    const m = model(def);
    paint(m, 1, 1, "tilled");
    erase(m, 1, 1);
    expect(m.def.layers[0].data[1][1]).toBe("water");
  });

  it("writes an empty string when the palette is empty", () => {
    const def = makeDef({ layers: [{ name: "ground", data: grid(4, 4, "") }] });
    const m = model(def);
    erase(m, 2, 2);
    expect(m.def.layers[0].data[2][2]).toBe("");
  });
});

describe("setSpawn", () => {
  it("moves the spawn point", () => {
    const m = model(makeDef());
    setSpawn(m, 3, 2);
    expect(m.def.spawn).toEqual({ x: 3, y: 2 });
    expect(m.dirty).toBe(true);
  });

  it("clamps out-of-bounds coordinates", () => {
    const m = model(makeDef());
    setSpawn(m, -5, 2);
    expect(m.def.spawn.x).toBe(0);
    setSpawn(m, 100, 100);
    expect(m.def.spawn).toEqual({ x: 3, y: 3 });
  });

  it("rejects non-integer coordinates", () => {
    const m = model(makeDef());
    setSpawn(m, Number.NaN, 1);
    setSpawn(m, 1.5, 1);
    expect(m.def.spawn).toEqual({ x: 1, y: 1 });
    expect(m.dirty).toBe(false);
  });
});

describe("toggleWalkable", () => {
  it("sets absent ids to false", () => {
    const m = model(makeDef());
    expect(m.def.walkable).toBeUndefined();
    toggleWalkable(m, "grass");
    expect(m.def.walkable?.grass).toBe(false);
    expect(m.dirty).toBe(true);
  });

  it("deletes the key when already false (restores fallback)", () => {
    const m = model(makeDef());
    toggleWalkable(m, "grass");
    toggleWalkable(m, "grass");
    expect(m.def.walkable).toBeUndefined();
  });

  it("sets true entries to false", () => {
    const def = makeDef();
    def.walkable = { grass: true };
    const m = model(def);
    toggleWalkable(m, "grass");
    expect(m.def.walkable?.grass).toBe(false);
  });

  it("keeps unrelated entries when deleting one", () => {
    const def = makeDef();
    def.walkable = { water: false, tilled: false };
    const m = model(def);
    toggleWalkable(m, "water");
    expect(m.def.walkable).toEqual({ tilled: false });
  });

  it("ignores the empty tile id", () => {
    const m = model(makeDef());
    toggleWalkable(m, "");
    expect(m.def.walkable).toBeUndefined();
    expect(m.dirty).toBe(false);
  });
});

describe("addTileId", () => {
  it("registers a palette id without touching the def", () => {
    const m = model(makeDef());
    const defBefore = JSON.stringify(m.def);
    addTileId(m, "sand");
    expect(m.palette).toContain("sand");
    expect(JSON.stringify(m.def)).toBe(defBefore);
    expect(m.dirty).toBe(false);
    addTileId(m, "sand");
    expect(m.palette.filter((id) => id === "sand")).toHaveLength(1);
    addTileId(m, "");
    expect(m.palette).not.toContain("");
  });
});

describe("serialize", () => {
  it("roundtrips model → def → model identity for the same def", () => {
    const def = makeDef({ walkable: { water: false }, tiles: { grass: "grass-1" } });
    const m = model(def);
    const out = serialize(m);
    expect(out).not.toBeNull();
    expect(out).toEqual(def);
    expect(out).not.toBe(m.def);
    expect(mapSchema.safeParse(out as MapDef).success).toBe(true);
  });

  it("returns a fresh object reflecting edits", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "tilled");
    setSpawn(m, 0, 0);
    const out = serialize(m);
    expect(out?.layers[0].data[0][0]).toBe("tilled");
    expect(out?.spawn).toEqual({ x: 0, y: 0 });
  });

  it("rejects an invalid working copy", () => {
    const m = model(makeDef());
    m.def.layers[0].data[0].length = 99;
    expect(serialize(m)).toBeNull();
  });
});

describe("collectTileIds", () => {
  it("collects unique ids from all layers in stable order", () => {
    const def: MapDef = {
      id: "t",
      width: 2,
      height: 2,
      tilesetRef: "ts",
      spawn: { x: 0, y: 0 },
      layers: [
        { name: "ground", data: [["water", "grass"], ["grass", "tilled"]] },
        { name: "deco", data: [["rock", "grass"], ["", "rock"]] },
      ],
    };
    const m = model(def);
    expect(collectTileIds(m)).toEqual(["water", "grass", "tilled", "rock"]);
  });
});

describe("tileColor", () => {
  it("keeps known tiles stable and special-cased", () => {
    expect(tileColor("grass")).toBe("#7cb342");
    expect(tileColor("water")).toBe("#4fc3f7");
    expect(tileColor("tilled")).toBe("#8d6e63");
    expect(tileColor("")).toBe(UNKNOWN_TILE_COLOR);
  });

  it("is stable for unknown ids and format is a hue", () => {
    expect(tileColor("rock")).toBe(tileColor("rock"));
    expect(tileColor("rock")).toMatch(/^hsl\(\d+ 55% 55%\)$/);
    expect(tileColor("rock")).not.toBe(tileColor("sand"));
  });
});

describe("isWalkableTile", () => {
  it("honours declared walkable entries", () => {
    const def = makeDef();
    def.walkable = { water: false, tilled: true };
    const m = model(def);
    expect(isWalkableTile(m, "water")).toBe(false);
    expect(isWalkableTile(m, "tilled")).toBe(true);
  });

  it("falls back to the engine's UNWALKABLE_TILES", () => {
    const m = model(makeDef());
    expect(isWalkableTile(m, "water")).toBe(false);
    expect(isWalkableTile(m, "grass")).toBe(true);
    expect(isWalkableTile(m, "rock")).toBe(true);
  });
});

describe("pointToTile", () => {
  it("maps pixel offsets to grid tiles", () => {
    expect(pointToTile(0, 0)).toEqual({ x: 0, y: 0 });
    expect(pointToTile(31, 31)).toEqual({ x: 0, y: 0 });
    expect(pointToTile(32, 64)).toEqual({ x: 1, y: 2 });
    expect(pointToTile(-5, 3)).toEqual({ x: -1, y: 0 });
    expect(TILE_SIZE).toBe(32);
  });
});

describe("dirty lifecycle", () => {
  it("tracks edits and clears on markSaved", () => {
    const m = model(makeDef());
    expect(m.dirty).toBe(false);
    paint(m, 0, 0, "water");
    expect(m.dirty).toBe(true);
    markSaved(m);
    expect(m.dirty).toBe(false);
    erase(m, 0, 0);
    expect(m.dirty).toBe(true);
    markSaved(m);
    setSpawn(m, 2, 2);
    expect(m.dirty).toBe(true);
    markSaved(m);
    toggleWalkable(m, "grass");
    expect(m.dirty).toBe(true);
    markSaved(m);
    addTileId(m, "sand");
    expect(m.dirty).toBe(false);
  });
});

describe("real map fixture end-to-end", () => {
  it("edits a real farm.yaml through parse → model → serialize → stringify → parse", async () => {
    const text = await readFile(join(fixturesDir, "farm.yaml"), "utf8");
    const m = createMapModel(parse(text));
    expect(m).not.toBeNull();
    if (m === null) throw new Error("fixture must be a valid map");
    expect(mapSchema.safeParse(m.def).success).toBe(true);
    expect(m.def.width).toBe(16);
    expect(m.def.spawn).toEqual({ x: 2, y: 4 });

    paint(m, 0, 0, "grass");
    setSpawn(m, 4, 4);
    toggleWalkable(m, "tilled");

    const out = serialize(m);
    expect(out).not.toBeNull();
    if (out === null) throw new Error("edited fixture must serialize");

    const yaml = stringify(out);
    const reparsed = parse(yaml);
    expect(reparsed).toEqual(out);
    expect(mapSchema.safeParse(reparsed).success).toBe(true);

    const m2 = createMapModel(reparsed);
    expect(m2).not.toBeNull();
    expect(m2?.def.layers[0].data[0][0]).toBe("grass");
    expect(m2?.def.spawn).toEqual({ x: 4, y: 4 });
    expect(m2?.def.walkable).toEqual({ water: false, tilled: false });
    expect(m2?.def.tiles?.water).toBe("water-1");

    expect(await readFile(join(fixturesDir, "farm.yaml"), "utf8")).toBe(text);
  });
});

describe("undo/redo", () => {
  it("paint then undo restores the cell, clears dirty, and redo re-applies", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    expect(m.dirty).toBe(true);
    expect(canUndo(m)).toBe(true);
    expect(undo(m)).toBe(true);
    expect(m.def.layers[0].data[0][0]).toBe("grass");
    expect(m.dirty).toBe(false);
    expect(canUndo(m)).toBe(false);
    expect(redo(m)).toBe(true);
    expect(m.def.layers[0].data[0][0]).toBe("water");
    expect(m.dirty).toBe(true);
  });

  it("erase records its actual write (before/after), not the erase intent", () => {
    const m = model(makeDef());
    paint(m, 2, 2, "water");
    markSaved(m);
    erase(m, 2, 2);
    expect(m.def.layers[0].data[2][2]).toBe("grass");
    expect(undo(m)).toBe(true);
    expect(m.def.layers[0].data[2][2]).toBe("water");
  });

  it("setSpawn undo restores the previous (clamped) coordinates", () => {
    const m = model(makeDef());
    setSpawn(m, 3, 3);
    expect(m.def.spawn).toEqual({ x: 3, y: 3 });
    expect(undo(m)).toBe(true);
    expect(m.def.spawn).toEqual({ x: 1, y: 1 });
  });

  it("toggleWalkable undo restores the record entry (and deletion restores the false entry)", () => {
    const m = model(makeDef());
    toggleWalkable(m, "grass"); // absent → false
    expect(m.def.walkable).toEqual({ grass: false });
    expect(undo(m)).toBe(true);
    expect(m.def.walkable).toBeUndefined();
    toggleWalkable(m, "grass");
    toggleWalkable(m, "grass"); // false → deleted
    expect(m.def.walkable).toBeUndefined();
    expect(undo(m)).toBe(true);
    expect(m.def.walkable).toEqual({ grass: false });
  });

  it("walkable undo restores an earlier unrelated entry of a multi-entry record", () => {
    const m = model(makeDef({ walkable: { water: false } }));
    toggleWalkable(m, "grass");
    undo(m);
    expect(m.def.walkable).toEqual({ water: false });
  });

  it("no-ops never enter the stack: same-value paint, same spawn, out-of-bounds paint", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "grass"); // same value
    paint(m, 99, 99, "water"); // out of bounds
    setSpawn(m, 1, 1); // unchanged (clamped to same)
    expect(m.history.length).toBe(0);
    expect(m.dirty).toBe(false);
  });

  it("ops unwind LIFO and a new op clears the redo stack", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    paint(m, 1, 1, "water");
    undo(m);
    undo(m);
    expect(redo(m)).toBe(true);
    paint(m, 3, 3, "water"); // new op
    expect(canRedo(m)).toBe(false);
    expect(redo(m)).toBe(false);
  });

  it("markSaved is a checkpoint: it clears both stacks and dirty", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    undo(m);
    markSaved(m);
    expect(m.history.length).toBe(0);
    expect(m.future.length).toBe(0);
    expect(m.dirty).toBe(false);
    expect(canUndo(m)).toBe(false);
    expect(canRedo(m)).toBe(false);
  });

  it("undoing everything returns to the saved state (Save button clears)", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    paint(m, 1, 1, "water");
    setSpawn(m, 2, 2);
    expect(m.dirty).toBe(true);
    while (undo(m)) {
      // drain
    }
    expect(m.dirty).toBe(false);
    expect(m.def.spawn).toEqual({ x: 1, y: 1 });
    expect(m.def.layers[0].data[0][0]).toBe("grass");
    expect(m.def.layers[0].data[1][1]).toBe("grass");
  });

  it("palette is additive and does not roll back on undo", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "rock");
    expect(m.palette).toContain("rock");
    undo(m);
    expect(m.palette).toContain("rock");
  });

  it("undo/redo return false on empty stacks", () => {
    const m = model(makeDef());
    expect(undo(m)).toBe(false);
    expect(redo(m)).toBe(false);
  });
});

describe("resizeMap", () => {
  it("grows width/height padding rows and columns with the erase tile", () => {
    const m = model(makeDef());
    expect(resizeMap(m, 6, 5)).toBe(true);
    expect(m.def.width).toBe(6);
    expect(m.def.height).toBe(5);
    expect(m.def.layers[0].data.length).toBe(5);
    for (const row of m.def.layers[0].data) expect(row.length).toBe(6);
    expect(m.def.layers[0].data[4].every((tile) => tile === DEFAULT_ERASE_TILE)).toBe(true);
    expect(serialize(m)).not.toBeNull();
  });

  it("shrinks by truncating and keeps non-square shapes", () => {
    const m = model(makeDef({ width: 8, height: 10, layers: [{ name: "ground", data: grid(8, 10) }] }));
    expect(resizeMap(m, 20, 3)).toBe(true);
    expect(m.def.width).toBe(20);
    expect(m.def.height).toBe(3);
    expect(m.def.layers[0].data.length).toBe(3);
    for (const row of m.def.layers[0].data) expect(row.length).toBe(20);
    expect(serialize(m)).not.toBeNull();
  });

  it("resizes every layer, not just the ground layer", () => {
    const m = model(
      makeDef({ layers: [{ name: "ground", data: grid(4, 4) }, { name: "overlay", data: grid(4, 4, "") }] }),
    );
    expect(resizeMap(m, 6, 6)).toBe(true);
    for (const layer of m.def.layers) {
      expect(layer.data.length).toBe(6);
      for (const row of layer.data) expect(row.length).toBe(6);
    }
  });

  it("clamps an out-of-range spawn into the new bounds", () => {
    const m = model(makeDef({ width: 12, height: 12, spawn: { x: 10, y: 10 }, layers: [{ name: "ground", data: grid(12, 12) }] }));
    expect(resizeMap(m, 4, 4)).toBe(true);
    expect(m.def.spawn).toEqual({ x: 3, y: 3 });
  });

  it("rejects non-positive/non-integer dimensions and unchanged sizes, leaving the def untouched", () => {
    const m = model(makeDef());
    const before = JSON.stringify(m.def);
    expect(resizeMap(m, 0, 4)).toBe(false);
    expect(resizeMap(m, 4, -1)).toBe(false);
    expect(resizeMap(m, 4.5, 4)).toBe(false);
    expect(resizeMap(m, Number.NaN, 4)).toBe(false);
    expect(resizeMap(m, 4, 4)).toBe(false);
    expect(JSON.stringify(m.def)).toBe(before);
    expect(m.history.length).toBe(0);
  });

  it("resize is undoable/redoable via the full-grid snapshot", () => {
    const m = model(makeDef({ width: 8, height: 8, spawn: { x: 6, y: 6 }, layers: [{ name: "ground", data: grid(8, 8) }] }));
    expect(resizeMap(m, 4, 4)).toBe(true);
    expect(undo(m)).toBe(true);
    expect(m.def.width).toBe(8);
    expect(m.def.height).toBe(8);
    expect(m.def.spawn).toEqual({ x: 6, y: 6 });
    expect(m.def.layers[0].data.length).toBe(8);
    expect(m.def.layers[0].data[0].length).toBe(8);
    expect(redo(m)).toBe(true);
    expect(m.def.width).toBe(4);
    expect(serialize(m)).not.toBeNull();
  });
});

describe("tileAssetId", () => {
  it("returns the asset id for a mapped tile and undefined otherwise", () => {
    const m = model(makeDef({ tiles: { grass: "grass-1", water: "water-1" } }));
    expect(tileAssetId(m, "grass")).toBe("grass-1");
    expect(tileAssetId(m, "sand")).toBeUndefined();
  });

  it("returns undefined without a tiles record", () => {
    expect(tileAssetId(model(makeDef()), "grass")).toBeUndefined();
  });
});

describe("clearHistory (bug-fix round)", () => {
  it("drops both stacks but keeps the dirty flag — an edit is an unsaved edit", () => {
    const m = model(makeDef());
    paint(m, 0, 0, "water");
    clearHistory(m);
    expect(m.history.length).toBe(0);
    expect(m.future.length).toBe(0);
    expect(m.dirty).toBe(true); // the painted tile is still unsaved
    expect(canUndo(m)).toBe(false);
    expect(serialize(m)?.layers[0].data[0][0]).toBe("water");
    // markSaved is the only way back to clean.
    markSaved(m);
    expect(m.dirty).toBe(false);
  });
});