#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <math.h>
#include <stdbool.h>
#include <jack/jack.h>
#include <jack/midiport.h>
#include <pthread.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <stdatomic.h>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

// Test configuration
#define TEST_SAMPLE_RATE 48000
#define TEST_NFRAMES 256
#define TEST_DURATION_SECONDS 1
#define MAX_CHANNELS 8
#define MAX_SCENES 8
#define MAX_CLIPS 512

// Hard timeout (seconds)
#define TEST_TIMEOUT_SECONDS 30

// Global test state
static pid_t looper_pid = -1;
static jack_client_t *test_client = NULL;
static jack_port_t *test_audio_out[MAX_CHANNELS];
static jack_port_t *test_audio_in[MAX_CHANNELS];
static jack_port_t *test_midi_out;
static jack_port_t *test_midi_in;
static atomic_bool test_running;
static atomic_bool test_timeout;
static atomic_int tests_passed;
static atomic_int tests_failed;

// Shared buffers for test audio input (written by test thread, read by JACK callback)
// Max samples = sample_rate * max_duration_seconds (sample_rate is typically 48000)
#define MAX_SAMPLES (48000 * TEST_DURATION_SECONDS)
static float test_audio_input[MAX_CHANNELS][MAX_SAMPLES];
static atomic_size_t test_audio_input_count[MAX_CHANNELS];
static atomic_size_t test_audio_input_read[MAX_CHANNELS];

// Shared MIDI buffer (written by test thread, read by JACK callback)
static uint8_t test_midi_buffer[3];  // status, note, velocity
static atomic_bool test_midi_pending;

// Test audio output buffers (written by JACK callback, read by test thread)
static float test_output_buffer[MAX_CHANNELS][MAX_SAMPLES];
static atomic_size_t test_output_count[MAX_CHANNELS];

// Mutex to protect shared buffers between main thread and JACK callback
static pthread_mutex_t test_buffer_mutex = PTHREAD_MUTEX_INITIALIZER;

// ============================================================
// Test framework
// ============================================================

#define TEST(name, expr) do { \
    if (expr) { \
        atomic_fetch_add(&tests_passed, 1); \
        printf("  PASS: %s\n", name); \
    } else { \
        atomic_fetch_add(&tests_failed, 1); \
        printf("  FAIL: %s\n", name); \
    } \
} while(0)

// ============================================================
// JACK test client callbacks
// ============================================================

static int test_process_callback(jack_nframes_t nframes, void *arg) {
    (void)arg;
    if (!atomic_load(&test_running)) return 0;
    
    pthread_mutex_lock(&test_buffer_mutex);
    
    // Write test audio to output ports (to be sent to looper)
    for (int ch = 0; ch < MAX_CHANNELS; ch++) {
        jack_default_audio_sample_t *out = (jack_default_audio_sample_t *)
            jack_port_get_buffer(test_audio_out[ch], nframes);
        
        size_t read_pos = atomic_load(&test_audio_input_read[ch]);
        size_t count = atomic_load(&test_audio_input_count[ch]);
        
        for (jack_nframes_t i = 0; i < nframes; i++) {
            if (read_pos + i < count) {
                out[i] = test_audio_input[ch][read_pos + i];
            } else {
                out[i] = 0.0f;
            }
        }
        atomic_store(&test_audio_input_read[ch], read_pos + nframes);
    }
    
    // Read audio from looper outputs
    for (int ch = 0; ch < MAX_CHANNELS; ch++) {
        jack_default_audio_sample_t *in = (jack_default_audio_sample_t *)
            jack_port_get_buffer(test_audio_in[ch], nframes);
        
        size_t count = atomic_load(&test_output_count[ch]);
        if (count + nframes <= MAX_SAMPLES) {
            for (jack_nframes_t i = 0; i < nframes; i++) {
                test_output_buffer[ch][count + i] = in[i];
            }
            atomic_store(&test_output_count[ch], count + nframes);
        }
    }
    
    // Send pending MIDI message to looper
    if (atomic_exchange(&test_midi_pending, false)) {
        void *midi_out_buf = jack_port_get_buffer(test_midi_out, nframes);
        jack_midi_clear_buffer(midi_out_buf);
        uint8_t msg[3];
        msg[0] = test_midi_buffer[0];
        msg[1] = test_midi_buffer[1];
        msg[2] = test_midi_buffer[2];
        jack_midi_event_write(midi_out_buf, 0, msg, 3);
    }
    
    // Read MIDI from looper
    void *midi_buf = jack_port_get_buffer(test_midi_in, nframes);
    jack_midi_event_t event;
    int event_count = jack_midi_get_event_count(midi_buf);
    for (int i = 0; i < event_count; i++) {
        jack_midi_event_get(&event, midi_buf, i);
        // Process MIDI events if needed
    }
    
    pthread_mutex_unlock(&test_buffer_mutex);
    
    return 0;
}

// ============================================================
// Helper functions
// ============================================================

static int start_looper(const char *client_name) {
    // Check if binary exists
    if (access("./jack-looper", X_OK) != 0) {
        fprintf(stderr, "Error: ./jack-looper binary not found or not executable\n");
        return -1;
    }
    
    looper_pid = fork();
    if (looper_pid == 0) {
        // Child process - start jack-looper
        // Set CPU limit for child
        struct rlimit cpu_limit;
        cpu_limit.rlim_cur = 10;  // 10 seconds CPU time
        cpu_limit.rlim_max = 10;
        setrlimit(RLIMIT_CPU, &cpu_limit);
        
        execl("./jack-looper", "jack-looper", "-n", client_name, "-i", NULL);
        perror("execl failed");
        exit(1);
    }
    if (looper_pid < 0) {
        perror("fork failed");
        return -1;
    }
    
    // Wait for looper to start
    usleep(500000);  // 500ms
    return 0;
}

static int stop_looper(void) {
    if (looper_pid > 0) {
        kill(looper_pid, SIGTERM);
        int status;
        waitpid(looper_pid, &status, 0);
        looper_pid = -1;
    }
    return 0;
}

static int connect_test_client(const char *looper_name) {
    jack_status_t status;
    test_client = jack_client_open("test_routing", JackNullOption, &status, NULL);
    if (!test_client) return -1;
    
    char port_name[64];
    for (int ch = 0; ch < MAX_CHANNELS; ch++) {
        snprintf(port_name, sizeof(port_name), "test_out_%d", ch);
        test_audio_out[ch] = jack_port_register(test_client, port_name,
                                                 JACK_DEFAULT_AUDIO_TYPE,
                                                 JackPortIsOutput, 0);
        
        snprintf(port_name, sizeof(port_name), "test_in_%d", ch);
        test_audio_in[ch] = jack_port_register(test_client, port_name,
                                                JACK_DEFAULT_AUDIO_TYPE,
                                                JackPortIsInput, 0);
        
        if (!test_audio_out[ch] || !test_audio_in[ch]) return -1;
    }
    
    test_midi_out = jack_port_register(test_client, "test_midi_out",
                                        JACK_DEFAULT_MIDI_TYPE,
                                        JackPortIsOutput, 0);
    test_midi_in = jack_port_register(test_client, "test_midi_in",
                                       JACK_DEFAULT_MIDI_TYPE,
                                       JackPortIsInput, 0);
    
    if (!test_midi_out || !test_midi_in) return -1;
    
    jack_set_process_callback(test_client, test_process_callback, NULL);
    
    if (jack_activate(test_client) != 0) return -1;
    
    // Connect test outputs to looper inputs
    for (int ch = 0; ch < MAX_CHANNELS; ch++) {
        char looper_port[64];
        snprintf(looper_port, sizeof(looper_port), "%s:audio_in_%d", looper_name, ch);
        snprintf(port_name, sizeof(port_name), "test_routing:test_out_%d", ch);
        jack_connect(test_client, port_name, looper_port);
        
        // Connect looper outputs to test inputs
        snprintf(looper_port, sizeof(looper_port), "%s:audio_out_%d", looper_name, ch);
        snprintf(port_name, sizeof(port_name), "test_routing:test_in_%d", ch);
        jack_connect(test_client, looper_port, port_name);
    }
    
    // Connect MIDI
    char looper_port[64];
    snprintf(looper_port, sizeof(looper_port), "%s:midi_control_in", looper_name);
    jack_connect(test_client, "test_routing:test_midi_out", looper_port);
    
    snprintf(looper_port, sizeof(looper_port), "%s:midi_out", looper_name);
    jack_connect(test_client, looper_port, "test_routing:test_midi_in");
    
    return 0;
}

static void disconnect_test_client(void) {
    if (test_client) {
        jack_client_close(test_client);
        test_client = NULL;
    }
}

static void send_sine_wave(int channel, float frequency, float amplitude, jack_nframes_t duration) {
    if (!test_client) return;
    if (atomic_load(&test_timeout)) return;
    
    jack_nframes_t sample_rate = jack_get_sample_rate(test_client);
    jack_nframes_t total_samples = (sample_rate * duration) / 1000;
    
    pthread_mutex_lock(&test_buffer_mutex);
    
    // Fill the shared input buffer
    for (jack_nframes_t i = 0; i < total_samples; i++) {
        test_audio_input[channel][i] = amplitude * sinf(2.0 * M_PI * frequency * i / sample_rate);
    }
    atomic_store(&test_audio_input_count[channel], total_samples);
    atomic_store(&test_audio_input_read[channel], 0);
    
    pthread_mutex_unlock(&test_buffer_mutex);
    
    // Wait for the JACK callback to consume the audio
    // (the callback runs in a separate thread)
    usleep(duration * 1000 + 100000);  // duration ms + 100ms extra
}

static void send_midi_note(int note, int velocity) {
    if (!test_client) return;
    if (atomic_load(&test_timeout)) return;
    
    pthread_mutex_lock(&test_buffer_mutex);
    
    // Store MIDI message for the JACK callback to send
    test_midi_buffer[0] = 0x90;  // Note On, channel 0
    test_midi_buffer[1] = note & 0x7F;
    test_midi_buffer[2] = velocity & 0x7F;
    atomic_store(&test_midi_pending, true);
    
    pthread_mutex_unlock(&test_buffer_mutex);
    
    usleep(100000);  // 100ms to let JACK process
}

static float get_channel_rms(int channel) {
    pthread_mutex_lock(&test_buffer_mutex);
    
    size_t count = atomic_load(&test_output_count[channel]);
    if (count == 0) {
        pthread_mutex_unlock(&test_buffer_mutex);
        return 0.0f;
    }
    
    double sum_sq = 0.0;
    for (size_t i = 0; i < count; i++) {
        sum_sq += test_output_buffer[channel][i] * test_output_buffer[channel][i];
    }
    
    pthread_mutex_unlock(&test_buffer_mutex);
    return sqrtf(sum_sq / count);
}

static void clear_output_buffers(void) {
    pthread_mutex_lock(&test_buffer_mutex);
    
    for (int ch = 0; ch < MAX_CHANNELS; ch++) {
        atomic_store(&test_output_count[ch], 0);
        memset(test_output_buffer[ch], 0, sizeof(test_output_buffer[ch]));
        atomic_store(&test_audio_input_count[ch], 0);
        atomic_store(&test_audio_input_read[ch], 0);
        memset(test_audio_input[ch], 0, sizeof(test_audio_input[ch]));
    }
    atomic_store(&test_midi_pending, false);
    
    pthread_mutex_unlock(&test_buffer_mutex);
}

// ============================================================
// Test cases
// ============================================================

static void test_basic_audio_routing(void) {
    printf("\nTest: Basic Audio Routing\n");
    
    clear_output_buffers();
    
    // Step 1: Start recording on clip 0 (note 0 triggers clip 0)
    send_midi_note(0, 100);
    usleep(100000);
    
    // Step 2: Send audio to channel 0 while recording
    send_sine_wave(0, 440.0, 0.5, 500);
    usleep(200000);
    
    // Step 3: Stop recording (toggle to looping)
    send_midi_note(0, 100);
    usleep(100000);
    
    // Step 4: Clear output and check that looped audio appears
    clear_output_buffers();
    usleep(300000);
    
    float rms_0 = get_channel_rms(0);
    float rms_1 = get_channel_rms(1);
    
    TEST("Channel 0 has audio output", rms_0 > 0.01f);
    TEST("Channel 1 has no audio (no input)", rms_1 < 0.01f);
}

static void test_multi_channel_routing(void) {
    printf("\nTest: Multi-Channel Audio Routing\n");
    
    clear_output_buffers();
    
    // Record clips on channels 0, 1, 2
    for (int ch = 0; ch < 3; ch++) {
        // Note ch triggers clip ch (since note % MAX_CLIPS = ch for ch < 512)
        send_midi_note(ch, 100);
        usleep(50000);
        send_sine_wave(ch, 440.0 * (ch + 1), 0.5, 300);
        usleep(50000);
        send_midi_note(ch, 100);  // Toggle to looping
        usleep(50000);
    }
    
    clear_output_buffers();
    usleep(300000);
    
    float rms[3];
    for (int ch = 0; ch < 3; ch++) {
        rms[ch] = get_channel_rms(ch);
    }
    
    TEST("Channel 0 has audio", rms[0] > 0.01f);
    TEST("Channel 1 has audio", rms[1] > 0.01f);
    TEST("Channel 2 has audio", rms[2] > 0.01f);
    TEST("Channel 3 has no audio (no input)", get_channel_rms(3) < 0.01f);
}

static void test_midi_clip_trigger(void) {
    printf("\nTest: MIDI Clip Trigger\n");
    
    clear_output_buffers();
    
    // Send MIDI note to trigger clip recording (note 0 triggers clip 0)
    send_midi_note(0, 100);
    usleep(100000);
    
    // Send audio to channel 0 while clip is recording
    send_sine_wave(0, 440.0, 0.5, 500);
    usleep(200000);
    
    // Send another MIDI note to stop recording (toggle to looping)
    send_midi_note(0, 100);
    usleep(100000);
    
    // Now the clip should be looping - clear output and check
    clear_output_buffers();
    usleep(300000);
    
    // Check that audio is still coming out (from the looped clip)
    float rms = get_channel_rms(0);
    TEST("Looped clip produces audio", rms > 0.01f);
}

static void test_midi_scene_launch(void) {
    printf("\nTest: MIDI Scene Launch\n");
    
    clear_output_buffers();
    
    // Record clips on channels 0-3 using notes 0-3
    for (int ch = 0; ch < 4; ch++) {
        send_midi_note(ch, 100);  // Start recording
        usleep(50000);
        send_sine_wave(ch, 440.0 * (ch + 1), 0.3, 200);
        usleep(50000);
        send_midi_note(ch, 100);  // Toggle to looping
        usleep(50000);
    }
    
    clear_output_buffers();
    usleep(300000);
    
    // All 4 channels should have audio from their looped clips
    for (int ch = 0; ch < 4; ch++) {
        float rms = get_channel_rms(ch);
        char test_name[64];
        snprintf(test_name, sizeof(test_name), "Channel %d has looped audio", ch);
        TEST(test_name, rms > 0.01f);
    }
}

static void test_channel_independence(void) {
    printf("\nTest: Channel Independence\n");
    
    clear_output_buffers();
    
    // Record on channel 0 only
    send_midi_note(0, 100);
    usleep(50000);
    send_sine_wave(0, 440.0, 0.8, 500);
    usleep(50000);
    send_midi_note(0, 100);  // Toggle to looping
    usleep(50000);
    
    clear_output_buffers();
    usleep(300000);
    
    float rms_0 = get_channel_rms(0);
    float rms_1 = get_channel_rms(1);
    float rms_2 = get_channel_rms(2);
    
    TEST("Channel 0 has strong signal", rms_0 > 0.1f);
    TEST("Channel 1 has no crosstalk", rms_1 < 0.01f);
    TEST("Channel 2 has no crosstalk", rms_2 < 0.01f);
}

static void test_volume_control(void) {
    printf("\nTest: Volume Control\n");
    
    clear_output_buffers();
    
    // Record on channel 0
    send_midi_note(0, 100);
    usleep(50000);
    send_sine_wave(0, 440.0, 0.5, 500);
    usleep(50000);
    send_midi_note(0, 100);  // Toggle to looping
    usleep(50000);
    
    clear_output_buffers();
    usleep(300000);
    
    float rms = get_channel_rms(0);
    TEST("Audio passes through at default volume", rms > 0.01f);
}

// ============================================================
// Main test runner
// ============================================================

// Watchdog thread - hard kill if test hangs
static void *watchdog_thread(void *arg) {
    (void)arg;
    sleep(TEST_TIMEOUT_SECONDS + 5);  // 5 seconds grace period
    if (atomic_load(&test_running)) {
        fprintf(stderr, "WATCHDOG: Test exceeded %d seconds, killing process\n", 
                TEST_TIMEOUT_SECONDS + 5);
        kill(getpid(), SIGKILL);
    }
    return NULL;
}

int main(void) {
    printf("=== Audio and MIDI Routing Integration Tests ===\n");
    printf("Note: These tests require JACK to be running\n\n");
    
    // Check available memory
    long pages = sysconf(_SC_PHYS_PAGES);
    long page_size = sysconf(_SC_PAGE_SIZE);
    long phys_mem = pages * page_size;
    long needed = sizeof(test_output_buffer);
    if (needed > phys_mem / 2) {
        fprintf(stderr, "Not enough memory for test buffers (need %ld, have %ld)\n", 
                needed, phys_mem / 2);
        return 1;
    }
    
    // Set CPU limit for this process
    struct rlimit cpu_limit;
    cpu_limit.rlim_cur = TEST_TIMEOUT_SECONDS;
    cpu_limit.rlim_max = TEST_TIMEOUT_SECONDS;
    setrlimit(RLIMIT_CPU, &cpu_limit);
    
    atomic_store(&tests_passed, 0);
    atomic_store(&tests_failed, 0);
    atomic_store(&test_running, true);
    atomic_store(&test_timeout, false);
    
    // Start watchdog thread
    pthread_t watchdog;
    pthread_create(&watchdog, NULL, watchdog_thread, NULL);
    pthread_detach(watchdog);
    
    // Start jack-looper
    printf("Starting jack-looper...\n");
    if (start_looper("test_looper") != 0) {
        fprintf(stderr, "Failed to start jack-looper\n");
        return 1;
    }
    printf("jack-looper started (PID: %d)\n", looper_pid);
    
    // Connect test client
    printf("Connecting test client...\n");
    if (connect_test_client("test_looper") != 0) {
        fprintf(stderr, "Failed to connect test client\n");
        stop_looper();
        return 1;
    }
    printf("Test client connected\n\n");
    
    // Run tests
    test_basic_audio_routing();
    test_multi_channel_routing();
    test_midi_clip_trigger();
    test_midi_scene_launch();
    test_channel_independence();
    test_volume_control();
    
    // Cleanup
    atomic_store(&test_running, false);
    disconnect_test_client();
    stop_looper();
    
    // Report results
    int passed = atomic_load(&tests_passed);
    int failed = atomic_load(&tests_failed);
    
    printf("\n=== Results ===\n");
    printf("Passed: %d\n", passed);
    printf("Failed: %d\n", failed);
    
    return failed > 0 ? 1 : 0;
}