#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdatomic.h>
#include <signal.h>
#include <unistd.h>
#include <pthread.h>
#include <time.h>
#include <setjmp.h>
#include "engine.h"

static volatile int keep_running = 1;
static jmp_buf segv_jmp;
static volatile int segv_caught = 0;

static void handle_sigint(int sig) {
    (void)sig;
    keep_running = 0;
}

// SIGSEGV handler to catch segfaults gracefully
static void handle_sigsegv(int sig) {
    (void)sig;
    segv_caught = 1;
    longjmp(segv_jmp, 1);
}

static Engine *create_stress_engine(void) {
    Engine *engine = (Engine *)calloc(1, sizeof(Engine));
    assert(engine != NULL);
    
    engine->control_channel = 0;
    engine->sample_rate = 48000;
    engine->quantize_mode = QUANTIZE_OFF;
    engine->quantize_threshold = 0;
    engine->queued_triggers = NULL;
    
    command_queue_init(&engine->command_queue);
    
    atomic_store(&engine->quantize_mode_atomic, (int)QUANTIZE_OFF);
    atomic_store(&engine->quantize_threshold_atomic, 0);
    
    engine->transport = (Transport *)calloc(1, sizeof(Transport));
    assert(engine->transport != NULL);
    transport_init(engine->transport, 48000);
    
    for (int i = 0; i < MAX_CLIPS; i++) {
        engine->clips[i].state = CLIP_EMPTY;
        engine->clips[i].buffer = (float *)calloc(MAX_BUFFER_SIZE, sizeof(float));
        assert(engine->clips[i].buffer != NULL);
        engine->clips[i].buffer_size = 0;
        engine->clips[i].write_position = 0;
        engine->clips[i].read_position = 0;
    }
    
    return engine;
}

static void destroy_stress_engine(Engine *engine) {
    if (engine) {
        // Free queued triggers first
        QueuedTrigger *qt = engine->queued_triggers;
        while (qt) {
            QueuedTrigger *next = qt->next;
            free(qt);
            qt = next;
        }
        engine->queued_triggers = NULL;
        
        if (engine->transport) {
            transport_cleanup(engine->transport);
            free(engine->transport);
            engine->transport = NULL;
        }
        for (int i = 0; i < MAX_CLIPS; i++) {
            free(engine->clips[i].buffer);
            engine->clips[i].buffer = NULL;
        }
        free(engine);
    }
}

// Random microsleep to expose race conditions
static void random_sleep_us(void) {
    struct timespec ts = {
        .tv_sec = 0,
        .tv_nsec = (rand() % 10000) * 100  // 0-999 microseconds
    };
    nanosleep(&ts, NULL);
}

// Stress test 1: Rapid clip triggers via command queue
static void stress_command_queue(void) {
    printf("Stress test 1: Rapid command queue submission...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 100000;
    int success = 0;
    int dropped = 0;
    for (int i = 0; i < num_ops; i++) {
        int clip_idx = i % MAX_CLIPS;
        int ret = engine_submit_command(engine, CMD_TRIGGER_CLIP, clip_idx, 0);
        if (ret == 0) {
            success++;
        } else {
            dropped++;
        }
        
        // Process commands periodically to prevent queue overflow
        if (i % 100 == 0) {
            engine_process_commands(engine);
        }
    }
    
    assert(success > 0);
    printf("  Submitted %d commands, %d succeeded, %d dropped\n", num_ops, success, dropped);
    
    // Process all commands
    engine_process_commands(engine);
    
    // Verify no commands left
    CommandQueue *q = &engine->command_queue;
    unsigned int write = atomic_load(&q->write_index);
    unsigned int read = atomic_load(&q->read_index);
    assert(write == read);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 2: Mix of clip and scene triggers
static void stress_mixed_triggers(void) {
    printf("Stress test 2: Mixed clip/scene triggers...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 50000;
    int success = 0;
    int dropped = 0;
    for (int i = 0; i < num_ops; i++) {
        int ret;
        if (i % 3 == 0) {
            int scene_idx = (i / 3) % MAX_SCENES;
            ret = engine_submit_command(engine, CMD_TRIGGER_SCENE, scene_idx, 0);
        } else {
            int clip_idx = i % MAX_CLIPS;
            ret = engine_submit_command(engine, CMD_TRIGGER_CLIP, clip_idx, 0);
        }
        if (ret == 0) {
            success++;
        } else {
            dropped++;
        }
        
        if (i % 50 == 0) {
            engine_process_commands(engine);
        }
    }
    
    assert(success > 0);
    printf("  Submitted %d commands, %d succeeded, %d dropped\n", num_ops, success, dropped);
    
    engine_process_commands(engine);
    
    CommandQueue *q = &engine->command_queue;
    assert(atomic_load(&q->write_index) == atomic_load(&q->read_index));
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 3: Queue overflow (should not crash)
static void stress_queue_overflow(void) {
    printf("Stress test 3: Queue overflow (should drop gracefully)...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = MAX_QUEUED_COMMANDS * 10;
    int dropped = 0;
    for (int i = 0; i < num_ops; i++) {
        int ret = engine_submit_command(engine, CMD_TRIGGER_CLIP, i % MAX_CLIPS, 0);
        if (ret != 0) dropped++;
    }
    
    assert(dropped > 0);
    printf("  Dropped %d commands (expected)\n", dropped);
    
    engine_process_commands(engine);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 4: Trigger pool exhaustion (simulate many MIDI notes)
static void stress_trigger_pool(void) {
    printf("Stress test 4: Trigger pool exhaustion...\n");
    Engine *engine = create_stress_engine();
    
    engine->transport->state = TRANSPORT_PLAYING;
    atomic_store(&engine->transport->state_atomic, TRANSPORT_PLAYING);
    engine->quantize_mode = QUANTIZE_BEAT;
    atomic_store(&engine->quantize_mode_atomic, (int)QUANTIZE_BEAT);
    
    int num_triggers = 10000;
    for (int i = 0; i < num_triggers; i++) {
        queue_trigger(engine, i % MAX_CLIPS, false, 100);
        
        // Periodically process to prevent memory exhaustion
        if (i % 1000 == 0) {
            QueuedTrigger *qt = engine->queued_triggers;
            int processed = 0;
            while (qt && processed < 500) {
                QueuedTrigger *next = qt->next;
                free(qt);
                qt = next;
                processed++;
            }
            engine->queued_triggers = qt;
        }
    }
    
    int count = 0;
    QueuedTrigger *qt = engine->queued_triggers;
    while (qt) {
        count++;
        qt = qt->next;
    }
    assert(count > 0);
    printf("  Queued %d triggers\n", count);
    
    qt = engine->queued_triggers;
    while (qt) {
        QueuedTrigger *next = qt->next;
        free(qt);
        qt = next;
    }
    engine->queued_triggers = NULL;
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 5: Undo/Redo stress
static void stress_undo_redo(void) {
    printf("Stress test 5: Undo/Redo stress...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 10000;
    int success = 0;
    int dropped = 0;
    for (int i = 0; i < num_ops; i++) {
        int clip_idx = i % MAX_CLIPS;
        int ret = engine_submit_command(engine, CMD_TRIGGER_CLIP, clip_idx, 0);
        if (ret == 0) success++; else dropped++;
        engine_process_commands(engine);
        
        if (i % 2 == 0) {
            ret = engine_submit_command(engine, CMD_UNDO, 0, 0);
            if (ret == 0) success++; else dropped++;
            engine_process_commands(engine);
        }
        
        // Rapid undo/redo cycles
        if (i % 10 == 0) {
            for (int j = 0; j < 5; j++) {
                engine_submit_command(engine, CMD_UNDO, 0, 0);
                engine_submit_command(engine, CMD_REDO, 0, 0);
            }
            engine_process_commands(engine);
        }
    }
    
    assert(success > 0);
    printf("  Submitted %d commands, %d succeeded, %d dropped\n", num_ops * 2, success, dropped);
    
    for (int i = 0; i < 1000; i++) {
        engine_submit_command(engine, CMD_REDO, 0, 0);
        engine_process_commands(engine);
    }
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 6: Transport state changes
static void stress_transport(void) {
    printf("Stress test 6: Transport state changes...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 50000;
    for (int i = 0; i < num_ops; i++) {
        switch (i % 5) {
            case 0:
                engine_submit_command(engine, CMD_TRANSPORT_PLAY, 0, 0);
                break;
            case 1:
                engine_submit_command(engine, CMD_TRANSPORT_PAUSE, 0, 0);
                break;
            case 2:
                engine_submit_command(engine, CMD_TRANSPORT_STOP, 0, 0);
                break;
            case 3:
                engine_submit_command(engine, CMD_TRANSPORT_TOGGLE_PLAY, 0, 0);
                break;
            case 4:
                engine_submit_command(engine, CMD_SET_CLOCK_SOURCE, (int)CLOCK_SOURCE_MIDI, 0);
                break;
        }
        
        if (i % 10 == 0) {
            engine_process_commands(engine);
        }
    }
    
    engine_process_commands(engine);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 7: Quantize mode changes
static void stress_quantize(void) {
    printf("Stress test 7: Quantize mode changes...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 50000;
    for (int i = 0; i < num_ops; i++) {
        QuantizeMode mode = (QuantizeMode)(i % 3);
        engine_submit_command(engine, CMD_SET_QUANTIZE_MODE, (int)mode, 0);
        engine_submit_command(engine, CMD_SET_QUANTIZE_THRESHOLD, 0, (jack_nframes_t)(i * 100));
        
        if (i % 5 == 0) {
            engine_submit_command(engine, CMD_TRIGGER_CLIP, i % MAX_CLIPS, 0);
        }
        
        if (i % 50 == 0) {
            engine_process_commands(engine);
        }
    }
    
    engine_process_commands(engine);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 8: Reset clips while triggering
static void stress_reset_while_triggering(void) {
    printf("Stress test 8: Reset clips while triggering...\n");
    Engine *engine = create_stress_engine();
    
    int num_ops = 10000;
    for (int i = 0; i < num_ops; i++) {
        int clip_idx = i % MAX_CLIPS;
        engine_submit_command(engine, CMD_TRIGGER_CLIP, clip_idx, 0);
        
        if (i % 3 == 0) {
            engine_submit_command(engine, CMD_RESET_CLIP, clip_idx, 0);
        }
        
        if (i % 5 == 0) {
            engine_submit_command(engine, CMD_TRIGGER_SCENE, i % MAX_SCENES, 0);
        }
        
        if (i % 10 == 0) {
            engine_process_commands(engine);
        }
    }
    
    engine_process_commands(engine);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 9: Null pointer handling
static void stress_null_pointers(void) {
    printf("Stress test 9: Null pointer handling...\n");
    
    // Call all functions with NULL engine
    engine_trigger_clip(NULL, 0);
    engine_trigger_scene(NULL, 0);
    engine_reset_clip(NULL, 0);
    engine_set_quantize_mode(NULL, QUANTIZE_OFF);
    engine_set_quantize_threshold(NULL, 0);
    engine_transport_stop(NULL);
    engine_transport_toggle_play(NULL);
    engine_set_clock_source(NULL, CLOCK_SOURCE_INTERNAL);
    engine_undo(NULL);
    engine_redo(NULL);
    engine_undo_action(NULL);
    engine_redo_action(NULL);
    engine_cleanup(NULL);
    engine_process_commands(NULL);
    queue_trigger(NULL, 0, false, 0);
    
    // Call with invalid indices
    Engine *engine = create_stress_engine();
    engine_trigger_clip(engine, -1);
    engine_trigger_clip(engine, MAX_CLIPS);
    engine_trigger_scene(engine, -1);
    engine_trigger_scene(engine, MAX_SCENES);
    engine_reset_clip(engine, -1);
    engine_reset_clip(engine, MAX_CLIPS);
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 10: Memory corruption detection
static void stress_memory_corruption(void) {
    printf("Stress test 10: Memory corruption detection...\n");
    
    // Rapid create/destroy cycles
    for (int i = 0; i < 1000; i++) {
        Engine *temp = create_stress_engine();
        destroy_stress_engine(temp);
    }
    
    // Stress with large allocations
    for (int i = 0; i < 100; i++) {
        float *big_buffer = (float *)calloc(MAX_BUFFER_SIZE * 10, sizeof(float));
        if (big_buffer) {
            free(big_buffer);
        }
    }
    
    printf("  PASSED\n");
}

// Stress test 11: Concurrent command submission (multi-threaded)
typedef struct {
    Engine *engine;
    int thread_id;
    int num_ops;
    int *success;
    int *dropped;
} ThreadArg;

static void *thread_worker(void *arg) {
    ThreadArg *targ = (ThreadArg *)arg;
    Engine *engine = targ->engine;
    int local_success = 0;
    int local_dropped = 0;
    
    for (int i = 0; i < targ->num_ops; i++) {
        int clip_idx = (targ->thread_id * 1000 + i) % MAX_CLIPS;
        int ret = engine_submit_command(engine, CMD_TRIGGER_CLIP, clip_idx, 0);
        if (ret == 0) {
            local_success++;
        } else {
            local_dropped++;
        }
        
        // Random sleep to increase chance of race conditions
        if (i % 100 == 0) {
            random_sleep_us();
        }
    }
    
    *targ->success = local_success;
    *targ->dropped = local_dropped;
    return NULL;
}

static void stress_concurrent(void) {
    printf("Stress test 11: Concurrent command submission (multi-threaded)...\n");
    Engine *engine = create_stress_engine();
    
    #define NUM_THREADS 8
    pthread_t threads[NUM_THREADS];
    ThreadArg args[NUM_THREADS];
    int successes[NUM_THREADS];
    int droppes[NUM_THREADS];
    
    int ops_per_thread = 10000;
    
    for (int t = 0; t < NUM_THREADS; t++) {
        args[t].engine = engine;
        args[t].thread_id = t;
        args[t].num_ops = ops_per_thread;
        args[t].success = &successes[t];
        args[t].dropped = &droppes[t];
        pthread_create(&threads[t], NULL, thread_worker, &args[t]);
    }
    
    // Wait for all worker threads to finish before processing commands
    for (int t = 0; t < NUM_THREADS; t++) {
        pthread_join(threads[t], NULL);
    }
    
    // Process all submitted commands
    engine_process_commands(engine);
    
    int total_success = 0;
    int total_dropped = 0;
    for (int t = 0; t < NUM_THREADS; t++) {
        total_success += successes[t];
        total_dropped += droppes[t];
    }
    
    printf("  %d threads, %d ops each, %d succeeded, %d dropped\n", 
           NUM_THREADS, ops_per_thread, total_success, total_dropped);
    
    CommandQueue *q = &engine->command_queue;
    assert(atomic_load(&q->write_index) >= atomic_load(&q->read_index));
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 12: Boundary conditions
static void stress_boundary(void) {
    printf("Stress test 12: Boundary conditions...\n");
    Engine *engine = create_stress_engine();
    
    // Test with transport in various states
    for (int state = 0; state < 3; state++) {
        engine->transport->state = (TransportState)state;
        atomic_store(&engine->transport->state_atomic, state);
        
        // Submit commands while transport is in each state
        for (int i = 0; i < 1000; i++) {
            engine_submit_command(engine, CMD_TRIGGER_CLIP, i % MAX_CLIPS, 0);
            engine_submit_command(engine, CMD_TRIGGER_SCENE, i % MAX_SCENES, 0);
            engine_submit_command(engine, CMD_RESET_CLIP, i % MAX_CLIPS, 0);
        }
        engine_process_commands(engine);
    }
    
    // Test with all quantize modes
    for (int mode = 0; mode < 3; mode++) {
        engine->quantize_mode = (QuantizeMode)mode;
        atomic_store(&engine->quantize_mode_atomic, mode);
        
        for (int i = 0; i < 1000; i++) {
            queue_trigger(engine, i % MAX_CLIPS, false, 100);
        }
        
        // Clean up
        QueuedTrigger *qt = engine->queued_triggers;
        while (qt) {
            QueuedTrigger *next = qt->next;
            free(qt);
            qt = next;
        }
        engine->queued_triggers = NULL;
    }
    
    destroy_stress_engine(engine);
    printf("  PASSED\n");
}

// Stress test 13: Rapid create/destroy with operations
static void stress_create_destroy(void) {
    printf("Stress test 13: Rapid create/destroy with operations...\n");
    
    for (int i = 0; i < 500; i++) {
        Engine *engine = create_stress_engine();
        
        // Do some operations
        for (int j = 0; j < 100; j++) {
            engine_submit_command(engine, CMD_TRIGGER_CLIP, j % MAX_CLIPS, 0);
            engine_submit_command(engine, CMD_TRANSPORT_TOGGLE_PLAY, 0, 0);
            engine_submit_command(engine, CMD_SET_QUANTIZE_MODE, j % 3, 0);
        }
        engine_process_commands(engine);
        
        // Queue some triggers
        for (int j = 0; j < 50; j++) {
            queue_trigger(engine, j % MAX_CLIPS, false, 100);
        }
        
        destroy_stress_engine(engine);
    }
    
    printf("  PASSED\n");
}

int main(void) {
    signal(SIGINT, handle_sigint);
    signal(SIGSEGV, handle_sigsegv);
    
    printf("Running JACK Looper stress tests (nuclear grade)...\n\n");
    
    // Set up segfault protection
    if (setjmp(segv_jmp) == 0) {
        stress_command_queue();
    } else {
        printf("  SEGFAULT CAUGHT in stress_command_queue!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_mixed_triggers();
    } else {
        printf("  SEGFAULT CAUGHT in stress_mixed_triggers!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_queue_overflow();
    } else {
        printf("  SEGFAULT CAUGHT in stress_queue_overflow!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_trigger_pool();
    } else {
        printf("  SEGFAULT CAUGHT in stress_trigger_pool!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_undo_redo();
    } else {
        printf("  SEGFAULT CAUGHT in stress_undo_redo!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_transport();
    } else {
        printf("  SEGFAULT CAUGHT in stress_transport!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_quantize();
    } else {
        printf("  SEGFAULT CAUGHT in stress_quantize!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_reset_while_triggering();
    } else {
        printf("  SEGFAULT CAUGHT in stress_reset_while_triggering!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_null_pointers();
    } else {
        printf("  SEGFAULT CAUGHT in stress_null_pointers!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_memory_corruption();
    } else {
        printf("  SEGFAULT CAUGHT in stress_memory_corruption!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_concurrent();
    } else {
        printf("  SEGFAULT CAUGHT in stress_concurrent!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_boundary();
    } else {
        printf("  SEGFAULT CAUGHT in stress_boundary!\n");
        return 1;
    }
    
    if (setjmp(segv_jmp) == 0) {
        stress_create_destroy();
    } else {
        printf("  SEGFAULT CAUGHT in stress_create_destroy!\n");
        return 1;
    }
    
    printf("\nAll stress tests passed!\n");
    return 0;
}