import { describe, expect, test } from "vitest";
import {
  decodePeachScript,
  encodePeachScript,
  isPeachScript,
  normalisePeachScript,
} from "./peachScript";
import { IMPORT_LIMITS } from "../shared/import-limits";

describe("peachScript decode size bound (PB-26-010)", () => {
  test("decode rejects input above MAX_JSON_BYTES before allocating", () => {
    // Build an oversized valid PeachScript string without the spread-arg
    // limit: repeat a 1K-char chunk past the 10 MiB bound.
    const chunk = String.fromCodePoint(0xe000).repeat(1024);
    const tooLarge = chunk.repeat(
      Math.floor(IMPORT_LIMITS.MAX_JSON_BYTES / 1024) + 1,
    );
    expect(tooLarge.length).toBeGreaterThan(IMPORT_LIMITS.MAX_JSON_BYTES);
    expect(() => decodePeachScript(tooLarge)).toThrow(
      "PEACHSCRIPT_TOO_LARGE",
    );
  });

  test("decode accepts input at the bound", () => {
    const atLimit = String.fromCodePoint(
      ...Array.from({ length: 64 }, () => 0xe041),
    );
    expect(decodePeachScript(atLimit).length).toBe(64);
  });
});

describe("peachScript", () => {
  test("byte 0 maps to U+E000", () => {
    const out = encodePeachScript(new Uint8Array([0]));
    expect(out.codePointAt(0)).toBe(0xe000);
  });

  test("byte 255 maps to U+E0FF", () => {
    const out = encodePeachScript(new Uint8Array([255]));
    expect(out.codePointAt(0)).toBe(0xe0ff);
  });

  test("round-trip identity for all 256 byte values", () => {
    const bytes = new Uint8Array(256);
    for (let i = 0; i < 256; i++) bytes[i] = i;
    const encoded = encodePeachScript(bytes);
    const decoded = decodePeachScript(encoded);
    expect(decoded).toEqual(bytes);
  });

  test("empty bytes round-trip to empty string and back", () => {
    expect(encodePeachScript(new Uint8Array())).toBe("");
    expect(decodePeachScript("")).toEqual(new Uint8Array());
  });

  test("decode throws on character outside PUA range", () => {
    expect(() => decodePeachScript("hello")).toThrow("INVALID_PEACHSCRIPT_CHARACTER");
    expect(() => decodePeachScript(String.fromCodePoint(0xe100))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
    expect(() => decodePeachScript(String.fromCodePoint(0xdfff))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  test("random-payload round-trip preserves bytes", () => {
    const payload = crypto.getRandomValues(new Uint8Array(2048));
    const decoded = decodePeachScript(encodePeachScript(payload));
    expect(decoded).toEqual(payload);
  });

  test("normalisePeachScript strips whitespace", () => {
    const encoded = encodePeachScript(new Uint8Array([1, 2, 3, 4]));
    const wrapped = encoded.slice(0, 2) + "\n  " + encoded.slice(2);
    expect(normalisePeachScript(wrapped)).toBe(encoded);
  });

  test("isPeachScript accepts only PUA strings", () => {
    expect(isPeachScript(encodePeachScript(new Uint8Array([1, 2, 3])))).toBe(true);
    expect(isPeachScript("")).toBe(false);
    expect(isPeachScript("hello")).toBe(false);
    const mixed = encodePeachScript(new Uint8Array([1])) + "x";
    expect(isPeachScript(mixed)).toBe(false);
  });
});

describe("peachScript fuzz corpus", () => {
  // Off-by-one boundary — U+E100 is one above the valid ceiling U+E0FF
  test("rejects U+E100 (off-by-one out of range)", () => {
    expect(() => decodePeachScript(String.fromCodePoint(0xe100))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  test("rejects U+E200 (far out of range)", () => {
    expect(() => decodePeachScript(String.fromCodePoint(0xe200))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  // Surrogate code points — below the valid PUA range U+E000..U+E0FF
  test("rejects lone low surrogate U+DFFF", () => {
    expect(() => decodePeachScript(String.fromCodePoint(0xdfff))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  test("rejects lone high surrogate U+D800", () => {
    expect(() => decodePeachScript(String.fromCodePoint(0xd800))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  // Real Mayan numerals are U+1D2E0..U+1D2F3 — outside PUA codec range
  test("rejects U+1D2E0 (real Mayan numeral — outside codec range)", () => {
    expect(() => decodePeachScript("\u{1D2E0}")).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  // BOM and Unicode direction/zero-width marks mid-stream
  test("rejects BOM (U+FEFF) mid-stream", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41, 0x42]));
    // U+FEFF = BOM, inject between two valid runes
    const withBOM = encoded[0] + String.fromCodePoint(0xfeff) + encoded[1];
    expect(() => decodePeachScript(withBOM)).toThrow("INVALID_PEACHSCRIPT_CHARACTER");
  });

  test("rejects RTL mark (U+200F) mid-stream", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41]));
    // U+200F = RIGHT-TO-LEFT MARK
    expect(() => decodePeachScript(encoded + String.fromCodePoint(0x200f))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  test("rejects zero-width non-joiner (U+200C)", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41]));
    // U+200C = ZERO WIDTH NON-JOINER
    expect(() => decodePeachScript(encoded + String.fromCodePoint(0x200c))).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });

  // Whitespace — the raw decoder is strict; normalisation is a separate step
  test("rejects space between valid rune characters", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41, 0x42]));
    const withSpace = encoded[0] + " " + encoded[1];
    expect(() => decodePeachScript(withSpace)).toThrow("INVALID_PEACHSCRIPT_CHARACTER");
  });

  test("rejects newline between valid rune characters", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41, 0x42]));
    const withNewline = encoded[0] + "\n" + encoded[1];
    expect(() => decodePeachScript(withNewline)).toThrow("INVALID_PEACHSCRIPT_CHARACTER");
  });

  // Boundary bytes must round-trip correctly
  test("byte 0x00 round-trips correctly", () => {
    const data = new Uint8Array([0x00]);
    expect(decodePeachScript(encodePeachScript(data))).toEqual(data);
  });

  test("byte 0xFE round-trips correctly", () => {
    const data = new Uint8Array([0xfe]);
    expect(decodePeachScript(encodePeachScript(data))).toEqual(data);
  });

  test("byte 0xFF round-trips correctly", () => {
    const data = new Uint8Array([0xff]);
    expect(decodePeachScript(encodePeachScript(data))).toEqual(data);
  });

  // 1 KiB pseudo-random round-trip
  test("1 KiB deterministic payload round-trips", () => {
    const data = new Uint8Array(1024);
    for (let i = 0; i < 1024; i++) data[i] = (i * 37 + 13) % 256;
    expect(decodePeachScript(encodePeachScript(data))).toEqual(data);
  });

  // DoS resistance — the decoder must fail on the first invalid character,
  // not after scanning the whole input. U+E100 > 0xE0FF fails on char 0.
  test("rejects large all-invalid input in well under 50 ms", () => {
    const invalid = String.fromCodePoint(0xe100).repeat(10_000);
    const start = Date.now();
    expect(() => decodePeachScript(invalid)).toThrow("INVALID_PEACHSCRIPT_CHARACTER");
    expect(Date.now() - start).toBeLessThan(50);
  });

  // Copy-paste hostility — smart quote prefix (U+201C = LEFT DOUBLE QUOTATION MARK)
  test("rejects left double quotation mark (U+201C) prefix", () => {
    const encoded = encodePeachScript(new Uint8Array([0x41]));
    expect(() => decodePeachScript(String.fromCodePoint(0x201c) + encoded)).toThrow(
      "INVALID_PEACHSCRIPT_CHARACTER"
    );
  });
});