/**
 * KHAELOR
 * File: tests/tui/frame.test.ts
 * Description: Renderer frame-composition tests — settling, damage tracking, cursor parking, sync fallback.
 *
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 */

import { describe, expect, it } from "vitest";
import { composeFrame } from "../../src/tui/renderer/frame.js";

const WIDTH = 80;

describe("composeFrame", () => {
  it("first paint repaints every row and parks the cursor at the caret", () => {
    const frame = composeFrame({
      prevLines: [],
      prevCaretRow: 0,
      next: { lines: ["tail", "status", "composer", "bar"], caretRow: 2, caretCol: 4 },
      settled: [],
      width: WIDTH,
      sync: true,
    });
    expect(frame.repaintedRows).toBe(4);
    expect(frame.lines).toEqual(["tail", "status", "composer", "bar"]);
    expect(frame.caretRow).toBe(2);
    // synchronized-output bracketing
    expect(frame.data.startsWith("\x1b[?2026h")).toBe(true);
    expect(frame.data.endsWith("\x1b[?2026l")).toBe(true);
    // cursor parked: up 1 from last row (row 3 → row 2), column 5 (1-based)
    expect(frame.data).toContain("\x1b[1A");
    expect(frame.data).toContain("\x1b[5G");
  });

  it("repaints only damaged rows on partial update", () => {
    const prev = ["tail", "status", "composer", "bar"];
    const frame = composeFrame({
      prevLines: prev,
      prevCaretRow: 2,
      next: { lines: ["tail", "status CHANGED", "composer", "bar"], caretRow: 2, caretCol: 4 },
      settled: [],
      width: WIDTH,
      sync: true,
    });
    expect(frame.repaintedRows).toBe(1);
    expect(frame.data).toContain("status CHANGED");
    // untouched rows are not re-emitted
    expect(frame.data).not.toContain("composer");
  });

  it("flushes settled blocks above the live region and full-repaints after", () => {
    const frame = composeFrame({
      prevLines: ["old-live", "composer"],
      prevCaretRow: 1,
      next: { lines: ["composer"], caretRow: 0, caretCol: 2 },
      settled: [["▸ Read src/a.ts · 12 lines"], ["✓ src/a.ts  +3 −1"]],
      width: WIDTH,
      sync: true,
    });
    // erase live region before printing settled content
    expect(frame.data).toContain("\x1b[0J");
    const settledIdx = frame.data.indexOf("▸ Read src/a.ts");
    const secondIdx = frame.data.indexOf("✓ src/a.ts");
    const liveIdx = frame.data.indexOf("composer");
    expect(settledIdx).toBeGreaterThan(-1);
    expect(secondIdx).toBeGreaterThan(settledIdx);
    expect(liveIdx).toBeGreaterThan(secondIdx);
    // settled lines end with \r\n so they scroll into scrollback
    expect(frame.data).toContain("▸ Read src/a.ts · 12 lines\r\n");
    expect(frame.repaintedRows).toBe(1); // full repaint of the (1-row) new region
  });

  it("erases below when the live region shrinks", () => {
    const frame = composeFrame({
      prevLines: ["a", "b", "c", "d"],
      prevCaretRow: 2,
      next: { lines: ["a", "b"], caretRow: 1, caretCol: 0 },
      settled: [],
      width: WIDTH,
      sync: true,
    });
    expect(frame.data).toContain("\x1b[0J");
    expect(frame.lines).toEqual(["a", "b"]);
  });

  it("falls back to cursor hide/show bracketing without sync support", () => {
    const frame = composeFrame({
      prevLines: [],
      prevCaretRow: 0,
      next: { lines: ["x"], caretRow: 0, caretCol: 1 },
      settled: [],
      width: WIDTH,
      sync: false,
    });
    expect(frame.data).not.toContain("\x1b[?2026h");
    expect(frame.data.startsWith("\x1b[?25l")).toBe(true);
    expect(frame.data).toContain("\x1b[?25h");
  });

  it("truncates every line to width − 1", () => {
    const long = "y".repeat(200);
    const frame = composeFrame({
      prevLines: [],
      prevCaretRow: 0,
      next: { lines: [long], caretRow: 0, caretCol: 0 },
      settled: [["s".repeat(200)]],
      width: 20,
      sync: true,
    });
    expect(frame.lines[0]).toBe("y".repeat(19));
    expect(frame.data).toContain("s".repeat(19) + "\r\n");
    expect(frame.data).not.toContain("s".repeat(20));
  });

  it("moves from the previous caret row to the live-region origin", () => {
    const frame = composeFrame({
      prevLines: ["a", "b", "c"],
      prevCaretRow: 1,
      next: { lines: ["a", "b", "c"], caretRow: 1, caretCol: 0 },
      settled: [],
      width: WIDTH,
      sync: true,
    });
    expect(frame.data).toContain("\x1b[1F"); // up 1 to origin from caret row 1
    expect(frame.repaintedRows).toBe(0); // nothing changed
  });
});