// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) 2026, The OpenROAD Authors

#include <atomic>
#include <chrono>
#include <cstddef>
#include <functional>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <utility>
#include <variant>
#include <vector>

#include "gtest/gtest.h"
#include "gui/gui.h"
#include "odb/db.h"
#include "odb/geom.h"
#include "tile_generator.h"
#include "web_chart.h"
#include "web_painter.h"
#include "web_viewer_hook.h"
namespace web {
namespace {

TEST(WebPainterTest, RecordsRect)
{
  WebPainter painter(odb::Rect(0, 0, 1000, 1000), 0.256);
  painter.setPen(gui::Painter::kRed, /*cosmetic=*/true);
  painter.setBrush(gui::Painter::kBlue);
  painter.drawRect(odb::Rect(10, 20, 100, 200));

  ASSERT_EQ(painter.ops().size(), 1u);
  const auto* rect = std::get_if<DrawRectOp>(painter.ops().data());
  ASSERT_NE(rect, nullptr);
  EXPECT_EQ(rect->rect.xMin(), 10);
  EXPECT_EQ(rect->rect.yMax(), 200);
  EXPECT_EQ(rect->pen.color.r, 0xff);
  EXPECT_TRUE(rect->pen.cosmetic);
  EXPECT_EQ(rect->brush.color.b, 0xff);
}

TEST(WebPainterTest, RecordsLine)
{
  WebPainter painter(odb::Rect(0, 0, 1000, 1000), 1.0);
  painter.setPen(gui::Painter::kGreen, /*cosmetic=*/false, /*width=*/3);
  painter.drawLine(odb::Point(1, 2), odb::Point(3, 4));

  ASSERT_EQ(painter.ops().size(), 1u);
  const auto* line = std::get_if<DrawLineOp>(painter.ops().data());
  ASSERT_NE(line, nullptr);
  EXPECT_EQ(line->p1.x(), 1);
  EXPECT_EQ(line->p2.y(), 4);
  EXPECT_EQ(line->pen.width, 3);
}

TEST(WebPainterTest, KeepsWideStrokeRectNearTileEdge)
{
  WebPainter painter(odb::Rect(0, 0, 100, 100), 1.0);
  painter.setPen(gui::Painter::kRed, /*cosmetic=*/true, /*width=*/4);
  painter.drawRect(odb::Rect(-2, 10, -1, 20));

  ASSERT_EQ(painter.ops().size(), 1u);
  EXPECT_NE(std::get_if<DrawRectOp>(painter.ops().data()), nullptr);
}

TEST(WebPainterTest, KeepsWideStrokeLineNearTileEdge)
{
  WebPainter painter(odb::Rect(0, 0, 100, 100), 1.0);
  painter.setPen(gui::Painter::kRed, /*cosmetic=*/true, /*width=*/4);
  painter.drawLine(odb::Point(-10, 101), odb::Point(110, 101));

  ASSERT_EQ(painter.ops().size(), 1u);
  EXPECT_NE(std::get_if<DrawLineOp>(painter.ops().data()), nullptr);
}

TEST(WebPainterTest, KeepsWideStrokeCircleNearTileEdge)
{
  WebPainter painter(odb::Rect(0, 0, 100, 100), 1.0);
  painter.setPen(gui::Painter::kRed, /*cosmetic=*/true, /*width=*/4);
  painter.drawCircle(102, 50, 1);

  ASSERT_EQ(painter.ops().size(), 1u);
  EXPECT_NE(std::get_if<DrawCircleOp>(painter.ops().data()), nullptr);
}

TEST(WebPainterTest, SaveRestoreState)
{
  WebPainter painter(odb::Rect(0, 0, 1000, 1000), 1.0);
  painter.setPen(gui::Painter::kRed);
  painter.saveState();
  painter.setPen(gui::Painter::kGreen);
  painter.drawRect(odb::Rect(0, 0, 10, 10));
  painter.restoreState();
  painter.drawRect(odb::Rect(0, 0, 10, 10));

  ASSERT_EQ(painter.ops().size(), 2u);
  const auto* r1 = std::get_if<DrawRectOp>(painter.ops().data());
  const auto* r2 = std::get_if<DrawRectOp>(&painter.ops()[1]);
  ASSERT_NE(r1, nullptr);
  ASSERT_NE(r2, nullptr);
  EXPECT_EQ(r1->pen.color.g, 0xff);  // green
  EXPECT_EQ(r2->pen.color.r, 0xff);  // red (restored)
}

// Helper: register a dummy client so pause() actually blocks
// (with no clients, pause() returns immediately).
static std::size_t registerDummyClient(WebViewerHook& hook)
{
  return hook.sessions().add([](const std::string&) {});
}

TEST(SessionRegistryTest, BroadcastAndWaitNoSessions)
{
  SessionRegistry registry;
  // No sessions registered — should return true immediately.
  EXPECT_TRUE(registry.broadcastAndWait("{}", std::chrono::milliseconds(100)));
}

TEST(SessionRegistryTest, BroadcastAndWaitFencesComplete)
{
  SessionRegistry registry;
  std::string received;

  // Register a session whose SendAndWaitFn invokes the fence only after
  // the simulated write has completed.
  auto token = registry.add(
      [&received](const std::string& json) { received = json; },
      [&received](const std::string& json, std::function<void()> fence) {
        std::thread([&received, json, fence = std::move(fence)]() {
          received = json;
          fence();
        }).detach();
      });

  EXPECT_TRUE(registry.broadcastAndWait(R"({"type":"shutdown"})",
                                        std::chrono::seconds(2)));
  EXPECT_EQ(received, R"({"type":"shutdown"})");
  registry.remove(token);
}

TEST(SessionRegistryTest, BroadcastAndWaitTimesOut)
{
  SessionRegistry registry;

  // Register a session whose SendAndWaitFn silently drops the fence.
  auto token = registry.add(
      [](const std::string&) {},
      [](const std::string&, const std::function<void()>& /*fence*/) {
        /* never called */
      });

  const auto t0 = std::chrono::steady_clock::now();
  EXPECT_FALSE(registry.broadcastAndWait("{}", std::chrono::milliseconds(200)));
  const auto elapsed = std::chrono::steady_clock::now() - t0;

  // Should have waited approximately the timeout, not longer.
  EXPECT_GE(elapsed, std::chrono::milliseconds(150));
  EXPECT_LT(elapsed, std::chrono::seconds(2));
  registry.remove(token);
}

TEST(SessionRegistryTest, BroadcastAndWaitDeadSession)
{
  SessionRegistry registry;
  std::atomic<bool> send_called{false};

  // Register a session whose SendAndWaitFn calls the fence immediately
  // (simulating a dead session that signals right away).
  auto token = registry.add(
      [&send_called](const std::string&) { send_called = true; },
      [&send_called](const std::string&, const std::function<void()>& fence) {
        send_called = true;
        fence();
      });

  EXPECT_TRUE(registry.broadcastAndWait("{}", std::chrono::milliseconds(100)));
  EXPECT_TRUE(send_called);
  registry.remove(token);
}

TEST(SessionRegistryTest, BroadcastAndWaitLegacySendOnly)
{
  SessionRegistry registry;
  std::string received;

  // Register with SendFn only (no SendAndWaitFn) — legacy path.
  auto token
      = registry.add([&received](const std::string& json) { received = json; });

  // Should return true immediately since there are no fenceable sessions.
  EXPECT_TRUE(registry.broadcastAndWait(R"({"ok":true})",
                                        std::chrono::milliseconds(100)));
  EXPECT_EQ(received, R"({"ok":true})");
  registry.remove(token);
}

TEST(SessionRegistryTest, WaitForClientCanBeInterrupted)
{
  SessionRegistry registry;
  std::atomic<bool> interrupted{false};
  std::atomic<bool> waiting{false};
  bool got_client = true;

  std::thread waiter([&]() {
    got_client = registry.waitForClient(/*timeout_seconds=*/30, [&]() {
      waiting.store(true);
      return interrupted.load();
    });
  });

  for (int i = 0; i < 200 && !waiting.load(); ++i) {
    std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
  ASSERT_TRUE(waiting.load());

  const auto t0 = std::chrono::steady_clock::now();
  interrupted.store(true);
  registry.notifyClientWaiters();
  waiter.join();

  const auto elapsed = std::chrono::steady_clock::now() - t0;
  EXPECT_FALSE(got_client);
  EXPECT_LT(elapsed, std::chrono::seconds(5));
}

TEST(WebViewerHookTest, PauseUnblocksOnContinue)
{
  WebViewerHook hook;
  auto token = registerDummyClient(hook);
  std::atomic<bool> resumed{false};
  std::thread waiter([&]() {
    hook.pause(/*timeout_ms=*/0);
    resumed.store(true);
  });

  // Wait up to 500ms for the waiter to be inside pause().  isPaused()
  // should flip to true during that window.
  for (int i = 0; i < 50 && !hook.isPaused(); ++i) {
    std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
  EXPECT_TRUE(hook.isPaused());

  hook.continueExecution();
  waiter.join();
  EXPECT_TRUE(resumed.load());
  EXPECT_FALSE(hook.isPaused());
  hook.sessions().remove(token);
}

TEST(WebViewerHookTest, PauseReturnsWhenNoClientsConnect)
{
  WebViewerHook hook;
  // No registered clients → pause waits for a client, then gives up.
  // Register a client after a short delay to unblock faster.
  std::thread late_register([&]() {
    // Don't register — let the wait-for-client timeout expire.
    // The internal timeout is 30s but we can't speed that up in a
    // unit test without injecting it as a parameter, so just verify
    // that pause() eventually returns and doesn't hang forever.
  });
  late_register.join();
  // Instead, test the fast path: register a client, then remove it
  // before calling pause.  pause() sees no clients and waits, but
  // we add one quickly to unblock.
  std::atomic<bool> done{false};
  std::thread pauser([&]() {
    hook.pause(/*timeout_ms=*/0);
    done.store(true);
  });
  // Give pause() a moment to enter waitForClient, then register.
  std::this_thread::sleep_for(std::chrono::milliseconds(50));
  auto token = registerDummyClient(hook);
  // Now pause is inside the pause CV wait — continue to unblock.
  std::this_thread::sleep_for(std::chrono::milliseconds(50));
  hook.continueExecution();
  pauser.join();
  EXPECT_TRUE(done.load());
  EXPECT_FALSE(hook.isPaused());
  hook.sessions().remove(token);
}

TEST(WebViewerHookTest, ContinueInterruptsWaitForClient)
{
  WebViewerHook hook;
  std::atomic<bool> done{false};
  std::thread pauser([&]() {
    hook.pause(/*timeout_ms=*/0);
    done.store(true);
  });

  // Give pause() a chance to enter the no-client wait.  continueExecution()
  // must wake that path instead of relying on the 30s client-connect timeout.
  std::this_thread::sleep_for(std::chrono::milliseconds(50));
  const auto t0 = std::chrono::steady_clock::now();
  hook.continueExecution();
  pauser.join();

  const auto elapsed = std::chrono::steady_clock::now() - t0;
  EXPECT_TRUE(done.load());
  EXPECT_LT(elapsed, std::chrono::seconds(5));
  EXPECT_FALSE(hook.isPaused());

  const auto token = registerDummyClient(hook);
  const auto t1 = std::chrono::steady_clock::now();
  hook.pause(/*timeout_ms=*/50);
  const auto next_elapsed = std::chrono::steady_clock::now() - t1;
  EXPECT_GE(next_elapsed, std::chrono::milliseconds(40));
  hook.sessions().remove(token);
}

TEST(WebViewerHookTest, DestructorUnblocksPausedThread)
{
  std::atomic<bool> resumed{false};
  std::thread waiter;
  {
    WebViewerHook hook;
    registerDummyClient(hook);
    waiter = std::thread([&]() {
      hook.pause(/*timeout_ms=*/0);
      resumed.store(true);
    });
    // Wait until the thread is definitely inside pause().
    for (int i = 0; i < 200 && !hook.isPaused(); ++i) {
      std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
    ASSERT_TRUE(hook.isPaused())
        << "Thread didn't reach pause() within 2s — test is broken";
  }  // hook destroyed → should signal cv → waiter returns
  waiter.join();
  EXPECT_TRUE(resumed.load());
}

TEST(WebViewerHookTest, PauseTimeoutReturns)
{
  WebViewerHook hook;
  registerDummyClient(hook);
  const auto t0 = std::chrono::steady_clock::now();
  hook.pause(/*timeout_ms=*/50);
  const auto elapsed = std::chrono::steady_clock::now() - t0;
  EXPECT_GE(elapsed, std::chrono::milliseconds(40));
  EXPECT_LT(elapsed, std::chrono::milliseconds(5000));
  EXPECT_FALSE(hook.isPaused());
}

TEST(WebViewerHookTest, SessionBroadcast)
{
  WebViewerHook hook;
  std::vector<std::string> seen;
  std::mutex m;
  const auto token = hook.sessions().add([&](const std::string& s) {
    std::lock_guard<std::mutex> lock(m);
    seen.push_back(s);
  });
  hook.redraw();
  hook.sessions().remove(token);
  hook.redraw();  // should not reach our callback

  std::lock_guard<std::mutex> lock(m);
  ASSERT_EQ(seen.size(), 1u);
  EXPECT_NE(seen[0].find("debug_refresh"), std::string::npos);
}

TEST(WebViewerHookTest, CreatesChartAndTracksIt)
{
  WebViewerHook hook;
  gui::Chart* c1 = hook.createChart("GPL", "iter", {"hpwl", "overflow"});
  ASSERT_NE(c1, nullptr);
  c1->setXAxisFormat("%d");
  c1->addPoint(0, {1.0, 2.0});
  c1->addPoint(1, {3.0, 4.0});

  const auto charts = hook.charts();
  ASSERT_EQ(charts.size(), 1u);
  EXPECT_EQ(charts[0]->name(), "GPL");
  EXPECT_EQ(charts[0]->xAxisFormat(), "%d");
  const auto pts = charts[0]->points();
  ASSERT_EQ(pts.size(), 2u);
  EXPECT_EQ(pts[1].x, 1);
  EXPECT_EQ(pts[1].ys[1], 4.0);
}

TEST(WebRasterizerTest, HonorsCosmeticPenWidth)
{
  std::unique_ptr<odb::dbDatabase, void (*)(odb::dbDatabase*)> db(
      odb::dbDatabase::create(), odb::dbDatabase::destroy);
  TileGenerator gen(db.get(), /*sta=*/nullptr, /*logger=*/nullptr);
  const odb::Rect dbu_tile(0, 0, 256, 256);
  const TileFrame frame{
      .origin_x = 0.0, .origin_y = 0.0, .scale = 1.0, .cull = dbu_tile};

  WebPainter narrow(dbu_tile, 1.0);
  narrow.setPen(gui::Painter::kRed, /*cosmetic=*/true, /*width=*/1);
  narrow.drawLine(odb::Point(10, 128), odb::Point(40, 128));

  WebPainter wide(dbu_tile, 1.0);
  wide.setPen(gui::Painter::kRed, /*cosmetic=*/true, /*width=*/4);
  wide.drawLine(odb::Point(10, 128), odb::Point(40, 128));

  const int image_bytes = 256 * 256 * 4;
  std::vector<unsigned char> narrow_image(image_bytes, 0);
  std::vector<unsigned char> wide_image(image_bytes, 0);
  gen.rasterizeWebPainterOps(narrow_image, narrow.ops(), frame);
  gen.rasterizeWebPainterOps(wide_image, wide.ops(), frame);

  const auto alpha_at
      = [](const std::vector<unsigned char>& image, int x, int y) {
          return image[(y * 256 + x) * 4 + 3];
        };
  const int screen_y = 255 - 128;
  EXPECT_EQ(alpha_at(narrow_image, 20, screen_y - 1), 0);
  EXPECT_GT(alpha_at(wide_image, 20, screen_y - 1), 0);
}

}  // namespace
}  // namespace web