// tests for the key-state tracker: tests/test_keystate.cpp
//
// The properties under test are the ones that decide whether the target machine
// ends up with a key stuck down: idempotence, transition preservation, rollover,
// and that clear() really clears.
#include <cstring>

#include "keystate.h"
#include "test.h"

using kr::KeyboardReport;
using kr::KeyboardState;

namespace {

// A report as 8 hex-byte triples, for readable assertions.
void hexreport(const KeyboardReport &r, char out[32]) {
  static const char kHex[] = "0123456789abcdef";
  const uint8_t bytes[8] = {r.modifiers, r.reserved, r.keys[0], r.keys[1], r.keys[2],
                            r.keys[3],    r.keys[4],  r.keys[5]};
  for (int i = 0; i < 8; i++) {
    out[3 * i] = kHex[bytes[i] >> 4];
    out[3 * i + 1] = kHex[bytes[i] & 0xF];
    out[3 * i + 2] = i == 7 ? '\0' : ' ';
  }
  out[23] = '\0';
}

}  // namespace

int main() {
  char h1[32], h2[32];

  CASE("empty state is all zeroes");
  {
    KeyboardState s;
    CHECK(!s.dirty());
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 00 00 00 00 00 00");
  }

  CASE("reserved byte is always zero");
  {
    KeyboardState s;
    const uint8_t keys[] = {kr::kUsageA};
    s.apply(kr::kModLctrl | kr::kModRgui, keys, 1);
    CHECK_EQ(s.report().reserved, 0);
    CHECK_EQ(s.report().modifiers, kr::kModLctrl | kr::kModRgui);
  }

  CASE("apply is idempotent -- same state twice dirties nothing");
  {
    KeyboardState s;
    const uint8_t keys[] = {kr::kUsageA, kr::kUsageZ};
    s.apply(kr::kModLshift, keys, 2);
    CHECK(s.dirty());
    s.ackDirty();
    s.apply(kr::kModLshift, keys, 2);
    CHECK(!s.dirty());
    s.apply(kr::kModLshift, keys, 2);
    CHECK(!s.dirty());
  }

  CASE("duplicates collapse, order is preserved");
  {
    KeyboardState s;
    const uint8_t keys[] = {kr::kUsageA, kr::kUsageA, kr::kUsageZ};
    s.apply(0, keys, 3);
    CHECK_EQ(s.held(), 2u);
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 04 1d 00 00 00 00");
    CHECK(s.isDown(kr::kUsageA));
    CHECK(s.isDown(kr::kUsageZ));
  }

  CASE("usage 0x00 is not a key");
  {
    KeyboardState s;
    const uint8_t keys[] = {0x00, kr::kUsageEnter, 0x00};
    s.apply(0, keys, 3);
    CHECK_EQ(s.held(), 1u);
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 28 00 00 00 00 00");
  }

  CASE("a distinct transition always produces a distinct report");
  {
    // A fast tap: press then release. Both states have to be reportable, or the
    // keypress vanishes and the target never sees the character.
    KeyboardState s;
    const uint8_t down[] = {kr::kUsageA};
    s.apply(0, down, 1);
    CHECK(s.dirty());
    s.ackDirty();
    const uint8_t none = 0;
    s.apply(0, &none, 0);
    CHECK(s.dirty());
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 00 00 00 00 00 00");
  }

  CASE("modifiers alone are a reportable change");
  {
    KeyboardState s;
    s.apply(kr::kModLalt, nullptr, 0);
    CHECK(s.dirty());
    CHECK_EQ(s.modifiers(), kr::kModLalt);
    s.apply(0, nullptr, 0);
    CHECK(s.dirty());
  }

  CASE("six keys is exactly the limit");
  {
    KeyboardState s;
    const uint8_t keys[] = {0x04, 0x05, 0x06, 0x07, 0x08, 0x09};
    s.apply(0, keys, 6);
    CHECK(!s.rollover());
    CHECK_EQ(s.held(), 6u);
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 04 05 06 07 08 09");
  }

  CASE("a seventh key reports ErrorRollOver in every slot");
  {
    KeyboardState s;
    const uint8_t keys[] = {0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A};
    s.apply(0, keys, 7);
    CHECK(s.rollover());
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 01 01 01 01 01 01");
    // ... and releasing back under the limit reports the real keys again, so the
    // host is never left with a phantom key held down.
    const uint8_t six[] = {0x04, 0x05, 0x06, 0x07, 0x08, 0x09};
    s.apply(0, six, 6);
    CHECK(!s.rollover());
    hexreport(s.report(), h2);
    CHECK_STR(h2, "00 00 04 05 06 07 08 09");
  }

  CASE("more keys than we track still cannot wedge the state");
  {
    KeyboardState s;
    uint8_t keys[40];
    for (size_t i = 0; i < sizeof(keys); i++) keys[i] = static_cast<uint8_t>(0x04 + (i % 0x1A));
    s.apply(0xFF, keys, sizeof(keys));
    CHECK(s.rollover());
    CHECK(s.held() <= kr::kMaxTrackedKeys);
    s.clear();
    CHECK_EQ(s.held(), 0u);
    CHECK_EQ(s.modifiers(), 0);
  }

  CASE("clear releases everything; a repeat clear adds nothing");
  {
    KeyboardState s;
    const uint8_t keys[] = {kr::kUsageA, kr::kUsageSpace};
    s.apply(kr::kModLctrl | kr::kModLshift, keys, 2);
    s.ackDirty();
    s.clear();
    CHECK(s.dirty());            // the all-keys-up report still has to go out
    hexreport(s.report(), h1);
    CHECK_STR(h1, "00 00 00 00 00 00 00 00");
    s.ackDirty();
    s.clear();
    CHECK(!s.dirty());           // nothing changed, so no pointless second report
    s.apply(kr::kModLctrl, nullptr, 0);
    CHECK(s.dirty());            // ... and a real change after a clear is still seen
  }

  CASE("makeReport builds the Ctrl+Alt+Del chord byte-exactly");
  {
    const uint8_t del = kr::kUsageDelForward;
    const KeyboardReport r =
        kr::makeReport(kr::kModLctrl | kr::kModLalt, &del, 1);
    hexreport(r, h1);
    // 05 = LCtrl|LAlt, 4C = "Delete Forward". This is the exact sequence Windows
    // accepts as the secure attention sequence and logind sees as CAD.
    CHECK_STR(h1, "05 00 4c 00 00 00 00 00");
  }

  CASE("makeReport rolls over on more than six keys");
  {
    const uint8_t keys[] = {0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A};
    const KeyboardReport r = kr::makeReport(0, keys, 7);
    CHECK_EQ(r.keys[0], kr::kUsageErrorRollover);
    CHECK_EQ(r.keys[5], kr::kUsageErrorRollover);
  }

  CASE("reportsEqual distinguishes modifiers and slots");
  {
    KeyboardReport a = {0, 0, {4, 5, 0, 0, 0, 0}};
    KeyboardReport b = a;
    CHECK(kr::reportsEqual(a, b));
    b.modifiers = kr::kModLshift;
    CHECK(!kr::reportsEqual(a, b));
    b = a;
    b.keys[2] = 9;
    CHECK(!kr::reportsEqual(a, b));
  }

  return report("keystate");
}