#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>

#include "wasm_c_api.h"

#define own

const int N_THREADS = 10;
const int N_REPS = 3;

// A function to be called from Wasm code.
own wasm_trap_t *
callback(const wasm_val_vec_t *args, wasm_val_vec_t *results)
{
    assert(args->data[0].kind == WASM_I32);
    printf("> Thread %d running\n", args->data[0].of.i32);
    return NULL;
}

typedef struct {
    wasm_engine_t *engine;
    wasm_shared_module_t *module;
    int id;
} thread_args;

void *
run(void *args_abs)
{
    thread_args *args = (thread_args *)args_abs;

    // Rereate store and module.
    own wasm_store_t *store = wasm_store_new(args->engine);
    own wasm_module_t *module = wasm_module_obtain(store, args->module);

    // Run the example N times.
    for (int i = 0; i < N_REPS; ++i) {
        usleep(100000);

        // Create imports.
        own wasm_functype_t *func_type =
            wasm_functype_new_1_0(wasm_valtype_new_i32());
        own wasm_func_t *func = wasm_func_new(store, func_type, callback);
        wasm_functype_delete(func_type);

        wasm_val_t val = WASM_I32_VAL((int32_t)args->id);
        own wasm_globaltype_t *global_type =
            wasm_globaltype_new(wasm_valtype_new_i32(), WASM_CONST);
        own wasm_global_t *global = wasm_global_new(store, global_type, &val);
        wasm_globaltype_delete(global_type);

        // Instantiate.
        wasm_extern_t *externs[] = {
            wasm_func_as_extern(func),
            wasm_global_as_extern(global),
        };
        wasm_extern_vec_t imports = WASM_ARRAY_VEC(externs);
        own wasm_instance_t *instance =
            wasm_instance_new(store, module, &imports, NULL);
        if (!instance) {
            printf("> Error instantiating module!\n");
            return NULL;
        }

        wasm_func_delete(func);
        wasm_global_delete(global);

        // Extract export.
        own wasm_extern_vec_t exports;
        wasm_instance_exports(instance, &exports);
        if (exports.size == 0) {
            printf("> Error accessing exports!\n");
            return NULL;
        }
        const wasm_func_t *run_func = wasm_extern_as_func(exports.data[0]);
        if (run_func == NULL) {
            printf("> Error accessing export!\n");
            return NULL;
        }

        wasm_instance_delete(instance);

        // Call.
        wasm_val_vec_t empty = WASM_EMPTY_VEC;
        wasm_trap_t *trap = wasm_func_call(run_func, &empty, &empty);
        if (trap) {
            printf("> Error calling function!\n");
            wasm_trap_delete(trap);
            return NULL;
        }

        wasm_extern_vec_delete(&exports);
    }

    wasm_module_delete(module);
    wasm_store_delete(store);

    free(args_abs);

    return NULL;
}

int
main(int argc, const char *argv[])
{
    // Initialize.
    wasm_engine_t *engine = wasm_engine_new();

    // Load binary.
#if WASM_ENABLE_AOT != 0 && WASM_ENABLE_INTERP == 0
    FILE *file = fopen("threads.aot", "rb");
#else
    FILE *file = fopen("threads.wasm", "rb");
#endif
    if (!file) {
        printf("> Error loading module!\n");
        return 1;
    }

    int ret = fseek(file, 0L, SEEK_END);
    if (ret == -1) {
        printf("> Error loading module!\n");
        fclose(file);
        return 1;
    }

    long file_size = ftell(file);
    if (file_size == -1) {
        printf("> Error loading module!\n");
        fclose(file);
        return 1;
    }

    ret = fseek(file, 0L, SEEK_SET);
    if (ret == -1) {
        printf("> Error loading module!\n");
        fclose(file);
        return 1;
    }

    wasm_byte_vec_t binary;
    wasm_byte_vec_new_uninitialized(&binary, file_size);
    if (fread(binary.data, file_size, 1, file) != 1) {
        printf("> Error loading module!\n");
        return 1;
    }
    fclose(file);

    // Compile and share.
    own wasm_store_t *store = wasm_store_new(engine);
    own wasm_module_t *module = wasm_module_new(store, &binary);
    if (!module) {
        printf("> Error compiling module!\n");
        return 1;
    }

    wasm_byte_vec_delete(&binary);

    own wasm_shared_module_t *shared = wasm_module_share(module);

    wasm_module_delete(module);
    wasm_store_delete(store);

    // Spawn threads.
    pthread_t threads[N_THREADS];
    for (int i = 0; i < N_THREADS; i++) {
        thread_args *args = malloc(sizeof(thread_args));
        args->id = i;
        args->engine = engine;
        args->module = shared;
        printf("Initializing thread %d...\n", i);
        pthread_create(&threads[i], NULL, &run, args);
    }

    for (int i = 0; i < N_THREADS; i++) {
        printf("Waiting for thread: %d\n", i);
        pthread_join(threads[i], NULL);
    }

    wasm_shared_module_delete(shared);
    wasm_engine_delete(engine);

    return 0;
}