/**
 * @file TriggerEngineGTest.cpp
 * @brief Unit tests for the StreamHub hub-side trigger FSM.
 *
 * @copyright Copyright 2015 F4E | European Joint Undertaking for ITER and
 * the Development of Fusion Energy ('Fusion for Energy').
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved
 * by the European Commission - subsequent versions of the EUPL (the "Licence")
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at: http://ec.europa.eu/idabc/eupl
 *
 * @warning Unless required by applicable law or agreed to in writing,
 * software distributed under the Licence is distributed on an "AS IS"
 * basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the Licence permissions and limitations under the Licence.
 */

#include "TriggerEngine.h"

#include <gtest/gtest.h>

using namespace StreamHub;
using MARTe::float64;

static TriggerConfig MakeConfig(TrigEdge edge, float64 threshold,
                                float64 windowSec, float64 prePercent,
                                TrigAcqMode mode = kTrigNormal) {
    TriggerConfig cfg;
    cfg.signalKey  = "src:sig";
    cfg.edge       = edge;
    cfg.threshold  = threshold;
    cfg.windowSec  = windowSec;
    cfg.prePercent = prePercent;
    cfg.mode       = mode;
    return cfg;
}

TEST(TriggerEngineGTest, TestInitialState) {
    TriggerEngine eng;
    EXPECT_EQ(kTrigIdle, eng.GetState());
    EXPECT_FALSE(eng.GetStopped());
    float64 tt, pre, post;
    EXPECT_FALSE(eng.GetFiredWindow(tt, pre, post));
}

TEST(TriggerEngineGTest, TestIdleIgnoresSamples) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0); /* would fire if armed */
    EXPECT_EQ(kTrigIdle, eng.GetState());
}

TEST(TriggerEngineGTest, TestRisingEdgeFires) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
    eng.CheckSample(1.0, 0.0);  /* primes prevValue */
    eng.CheckSample(2.0, 1.0);  /* 0.0 < 0.5 <= 1.0 → fire */
    EXPECT_EQ(kTrigCollecting, eng.GetState());

    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(2.0, tt);
    EXPECT_DOUBLE_EQ(0.2, pre);   /* 1.0 s × 20 % */
    EXPECT_DOUBLE_EQ(0.8, post);
}

TEST(TriggerEngineGTest, TestFirstSampleNeverFires) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    /* First sample above threshold must only prime the detector */
    eng.CheckSample(1.0, 2.0);
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

TEST(TriggerEngineGTest, TestFallingEdgeFires) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeFalling, 0.5, 1.0, 50.0));
    eng.Arm();
    eng.CheckSample(1.0, 1.0);
    eng.CheckSample(2.0, 1.5);  /* rising: must not fire */
    EXPECT_EQ(kTrigArmed, eng.GetState());
    eng.CheckSample(3.0, 0.2);  /* 1.5 > 0.5 >= 0.2 → fire */
    EXPECT_EQ(kTrigCollecting, eng.GetState());

    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(3.0, tt);
    EXPECT_DOUBLE_EQ(0.5, pre);
    EXPECT_DOUBLE_EQ(0.5, post);
}

TEST(TriggerEngineGTest, TestBothEdgesFire) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeBoth, 0.0, 1.0, 0.0));
    eng.Arm();
    eng.CheckSample(1.0, -1.0);
    eng.CheckSample(2.0, 1.0);  /* rising through 0 */
    EXPECT_EQ(kTrigCollecting, eng.GetState());

    eng.Arm();
    eng.CheckSample(3.0, 1.0);
    eng.CheckSample(4.0, -1.0); /* falling through 0 */
    EXPECT_EQ(kTrigCollecting, eng.GetState());
}

TEST(TriggerEngineGTest, TestNoFireBelowThreshold) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 5.0, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0);
    eng.CheckSample(3.0, 4.9);
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

TEST(TriggerEngineGTest, TestConfigClamping) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.0, 100.0, 150.0));
    TriggerConfig cfg = eng.GetConfig();
    EXPECT_DOUBLE_EQ(60.0, cfg.windowSec);
    EXPECT_DOUBLE_EQ(100.0, cfg.prePercent);

    eng.SetConfig(MakeConfig(kEdgeRising, 0.0, 1.0e-6, -5.0));
    cfg = eng.GetConfig();
    EXPECT_DOUBLE_EQ(1.0e-4, cfg.windowSec);
    EXPECT_DOUBLE_EQ(0.0, cfg.prePercent);
}

TEST(TriggerEngineGTest, TestConfigEpochIncrements) {
    TriggerEngine eng;
    MARTe::uint32 e0 = eng.GetConfigEpoch();
    eng.SetConfig(MakeConfig(kEdgeRising, 0.0, 1.0, 20.0));
    EXPECT_EQ(e0 + 1u, eng.GetConfigEpoch());
    eng.SetConfig(MakeConfig(kEdgeFalling, 1.0, 2.0, 30.0));
    EXPECT_EQ(e0 + 2u, eng.GetConfigEpoch());
}

TEST(TriggerEngineGTest, TestMarkTriggeredOnlyFromCollecting) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));

    /* Not collecting: no-op */
    eng.MarkTriggered();
    EXPECT_EQ(kTrigIdle, eng.GetState());
    eng.Arm();
    eng.MarkTriggered();
    EXPECT_EQ(kTrigArmed, eng.GetState());

    /* Collecting → triggered */
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());
    eng.MarkTriggered();
    EXPECT_EQ(kTrigTriggered, eng.GetState());
}

TEST(TriggerEngineGTest, TestDisarmResetsEverything) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.SetStopped(true);
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    eng.Disarm();
    EXPECT_EQ(kTrigIdle, eng.GetState());
    EXPECT_FALSE(eng.GetStopped());
    float64 tt, pre, post;
    EXPECT_FALSE(eng.GetFiredWindow(tt, pre, post));
}

TEST(TriggerEngineGTest, TestRearmResetsEdgeDetection) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0);
    eng.MarkTriggered();
    ASSERT_EQ(kTrigTriggered, eng.GetState());

    /* Re-arm: first sample only primes even if it crosses the threshold
     * relative to the value seen before the re-arm. */
    eng.Arm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
    eng.CheckSample(3.0, 0.0);
    EXPECT_EQ(kTrigArmed, eng.GetState());
    eng.CheckSample(4.0, 1.0);
    EXPECT_EQ(kTrigCollecting, eng.GetState());
    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(4.0, tt);
}

/* An edge that arrives while a capture is still being collected, or while it is
 * being handed out, used to be dropped on the floor: CheckSample returned early
 * in every state but ARMED, and the automatic rearm then waited for a FRESH
 * edge. The engine is therefore deaf from its own trigger point until the
 * capture has been harvested — a post-window — and then for the holdoff on top.
 *
 * On a sparse pulse train that rounds the capture spacing up to a whole pulse
 * period: at the default 1 s window the blind stretch is 1 s, so a 1 Hz train
 * was caught at 0.5 Hz and a wider window lost whole multiples. Remembering the
 * edge costs nothing, because the capture is built from the edge's own
 * timestamp out of a ring that still holds everything around it. */
TEST(TriggerEngineGTest, TestEdgeDuringCaptureFiresOnRearm) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0)); /* post = 0.8 */
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    /* A second pulse, clear of the capture in flight (1.1 + 0.8 = 1.9). */
    eng.CheckSample(2.4, 0.0);
    eng.CheckSample(2.5, 1.0);

    eng.MarkTriggered();
    eng.Rearm();
    EXPECT_EQ(kTrigCollecting, eng.GetState());

    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(2.5, tt); /* the remembered edge, not the rearm instant */
}

/* The remembered edge must not be one the capture in flight already covers, nor
 * one inside the holdoff — that guard exists to stop the ringing of a single
 * event re-triggering on itself, and it is measured from the trigger point, so
 * the two overlap rather than add. */
TEST(TriggerEngineGTest, TestEdgeInsideOwnCaptureIsNotRemembered) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0)); /* post = 0.8 */
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    /* Inside 1.1 + max(0.8, 0.2 holdoff) = 1.9: the capture owns this stretch. */
    eng.CheckSample(1.4, 0.0);
    eng.CheckSample(1.5, 1.0);

    eng.MarkTriggered();
    eng.Rearm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

/* A holdoff longer than the post-window is what decides the guard interval. */
TEST(TriggerEngineGTest, TestHoldoffOutlastingPostWindowGovernsRearm) {
    TriggerEngine eng;
    TriggerConfig cfg = MakeConfig(kEdgeRising, 0.5, 1.0, 80.0); /* post = 0.2 */
    cfg.holdoffSec = 2.0;
    eng.SetConfig(cfg);
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    /* Past the post-window but inside the holdoff (1.1 + 2.0 = 3.1): ignored. */
    eng.CheckSample(1.9, 0.0);
    eng.CheckSample(2.0, 1.0);
    /* Clear of it: remembered. */
    eng.CheckSample(3.4, 0.0);
    eng.CheckSample(3.5, 1.0);

    eng.MarkTriggered();
    eng.Rearm();
    ASSERT_EQ(kTrigCollecting, eng.GetState());
    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(3.5, tt);
}

/* Only the first qualifying edge is worth keeping; a later one would deliver
 * the same capture a pulse further on and skip the one in between. */
TEST(TriggerEngineGTest, TestFirstQualifyingEdgeWins) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    eng.CheckSample(2.4, 0.0);
    eng.CheckSample(2.5, 1.0); /* first past 1.9 */
    eng.CheckSample(3.4, 0.0);
    eng.CheckSample(3.5, 1.0); /* later, must not displace it */

    eng.MarkTriggered();
    eng.Rearm();
    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(2.5, tt);
}

/* Arm() is the user's own arm: it asks for the next event, not for one that has
 * already been and gone, so it drops anything remembered. */
TEST(TriggerEngineGTest, TestUserArmDiscardsRememberedEdge) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    eng.CheckSample(2.4, 0.0);
    eng.CheckSample(2.5, 1.0);
    eng.MarkTriggered();

    eng.Arm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

/* Reconfiguring drops it too: the edge would be latched against a window it was
 * never judged against. */
TEST(TriggerEngineGTest, TestSetConfigDiscardsRememberedEdge) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    eng.CheckSample(2.4, 0.0);
    eng.CheckSample(2.5, 1.0);
    eng.MarkTriggered();

    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 2.0, 20.0));
    eng.Rearm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

/* The comparator keeps running through the dead time, so the first sample after
 * an automatic rearm is measured against its real predecessor rather than being
 * spent seeding one. A rearm landing mid-pulse would otherwise miss that
 * pulse's edge as well as the ones it slept through. */
TEST(TriggerEngineGTest, TestRearmKeepsTrackingTheLevel) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    /* Falls back low during the capture: no rising edge, nothing remembered,
     * but the level is now known to be 0. */
    eng.CheckSample(2.0, 0.0);
    eng.MarkTriggered();
    eng.Rearm();
    ASSERT_EQ(kTrigArmed, eng.GetState());

    eng.CheckSample(2.1, 1.0); /* 0.0 → 1.0 across 0.5, on the very first sample */
    EXPECT_EQ(kTrigCollecting, eng.GetState());
    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(2.1, tt);
}

/* Idle is genuinely deaf: nothing is tracked and nothing is remembered, so a
 * disarmed hub cannot fire the moment it is armed again. */
TEST(TriggerEngineGTest, TestDisarmDiscardsRememberedEdge) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(1.1, 1.0);
    eng.CheckSample(2.4, 0.0);
    eng.CheckSample(2.5, 1.0);
    eng.MarkTriggered();

    eng.Disarm();
    eng.Rearm();
    EXPECT_EQ(kTrigArmed, eng.GetState());
}

TEST(TriggerEngineGTest, TestStoppedFlag) {
    TriggerEngine eng;
    EXPECT_FALSE(eng.GetStopped());
    eng.SetStopped(true);
    EXPECT_TRUE(eng.GetStopped());
    eng.SetStopped(false);
    EXPECT_FALSE(eng.GetStopped());
}

TEST(TriggerEngineGTest, TestWindowLatchedAtFireTime) {
    TriggerEngine eng;
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 1.0, 20.0));
    eng.Arm();
    eng.CheckSample(1.0, 0.0);
    eng.CheckSample(2.0, 1.0);
    ASSERT_EQ(kTrigCollecting, eng.GetState());

    /* Config edits after the fire must not change the latched window */
    eng.SetConfig(MakeConfig(kEdgeRising, 0.5, 10.0, 50.0));
    float64 tt, pre, post;
    ASSERT_TRUE(eng.GetFiredWindow(tt, pre, post));
    EXPECT_DOUBLE_EQ(0.2, pre);
    EXPECT_DOUBLE_EQ(0.8, post);
}