import { AnsiColorMode, AnsiTerminalDisplay } from "./ansi.ts";
import { Buffer, describe, expect, it } from "./deps.testing.ts";

function createTestDisplay(): {
  stdout: Buffer;
  stdin: Buffer;
  display: AnsiTerminalDisplay;
} {
  const stdout = new Buffer();
  const stdin = new Buffer();
  const display = new AnsiTerminalDisplay(stdout, stdin);
  return { stdout, stdin, display };
}

describe(AnsiTerminalDisplay, () => {
  it("clears the screen on init", async () => {
    const { stdout, display } = createTestDisplay();
    await display.init();
    checkSequence(stdout, "![2J");
    await display.uninit();
    checkSequence(stdout, "![2J![2J");
  });

  it("writes truecolor characters", async () => {
    const { stdout, display } = createTestDisplay();
    await display.setupPalette([
      { r: 0.0, g: 0.0, b: 0.0 },
      { r: 0.5, g: 0.1, b: 1.0 },
    ], AnsiColorMode.TRUECOLOR);
    await display.setChar({ x: 0, y: 0 }, { ch: "$", fg: 1, bg: 0 });
    checkSequence(stdout, "![38;2;128;26;255m![48;2;0;0;0m![1;1H$");
  });

  it("falls back to 256 colors", async () => {
    const { stdout, display } = createTestDisplay();
    const palette = await display.setupPalette([
      { r: 0.0, g: 0.0, b: 0.0 },
    ], AnsiColorMode.COLORS256);
    await display.setChar({ x: 0, y: 0 }, { ch: "a", fg: 0, bg: 1 });
    await display.setChar({ x: 0, y: 0 }, { ch: "b", fg: 2, bg: 3 });
    checkSequence(stdout, "![38;5;0m![48;5;1m![1;1Ha![38;5;2m![48;5;3m![1;1Hb");

    expect(palette[0]).toEqual({ r: 0, g: 0, b: 0 });
    expect(palette[3]).toEqual({ r: 0.5, g: 0.5, b: 0 });
    expect(palette[14]).toEqual({ r: 0, g: 1, b: 1 });
    expect(palette[67]).toEqual({ r: 0.2, g: 0.4, b: 0.6 });
    expect(palette[234]).toEqual({ r: 0.12, g: 0.12, b: 0.12 });
  });

  it("moves the cursor only when needed", async () => {
    const { stdout, display } = createTestDisplay();
    display.forceSize({ w: 4, h: 3 });
    await display.setChar({ x: 0, y: 0 }, { ch: "a", fg: 0, bg: 0 });
    await display.setChar({ x: 1, y: 0 }, { ch: "b", fg: 0, bg: 0 });
    await display.setChar({ x: 3, y: 0 }, { ch: "c", fg: 0, bg: 0 });
    await display.setChar({ x: 0, y: 1 }, { ch: "d", fg: 0, bg: 0 });
    await display.setChar({ x: 0, y: 2 }, { ch: "e", fg: 0, bg: 0 });
    checkSequence(stdout, "![1;1Hab![1;4Hcd![3;1He");
  });

  it("changes colors only when needed", async () => {
    const { stdout, display } = createTestDisplay();
    display.forceSize({ w: 10, h: 1 });
    await display.setupPalette([
      { r: 0.0, g: 0.0, b: 0.0 },
    ], AnsiColorMode.COLORS256);
    await display.setChar({ x: 0, y: 0 }, { ch: "a", fg: 1, bg: 0 });
    await display.setChar({ x: 1, y: 0 }, { ch: "b", fg: 1, bg: 0 });
    await display.setChar({ x: 2, y: 0 }, { ch: "c", fg: 2, bg: 0 });
    await display.setChar({ x: 3, y: 0 }, { ch: "d", fg: 0, bg: 2 });
    await display.setChar({ x: 4, y: 0 }, { ch: "e", fg: 0, bg: 2 });
    await display.setChar({ x: 5, y: 0 }, { ch: "f", fg: 0, bg: 3 });
    checkSequence(
      stdout,
      "![38;5;1m![48;5;0m![1;1Hab![38;5;2mc![38;5;0m![48;5;2mde![48;5;3mf",
    );
  });
});

function checkSequence(buffer: Buffer, expected: string) {
  const decoded = new TextDecoder().decode(
    buffer.bytes().map((x) => x == 0x1B ? 0x21 : x),
  );
  expect(decoded).toEqual(expected);
}