/* Initializes a new thread context. Note that this doesn't set up a
 * thread itself, it just creates the data structure that exists in
 * MoarVM per thread. */
MVMThreadContext * MVM_tc_create(MVMThreadContext *parent, MVMInstance *instance) {
    MVMThreadContext *tc = MVM_calloc(1, sizeof(MVMThreadContext));
    MVMint32 i;

    /* Associate with VM instance. */
    tc->instance = instance;

    /* Set up GC nursery. We only allocate tospace initially, and allocate
     * fromspace the first time this thread GCs, provided it ever does. */
    tc->nursery_tospace_size = MVM_gc_new_thread_nursery_size(instance);
    tc->nursery_tospace     = MVM_calloc(1, tc->nursery_tospace_size);
    tc->nursery_alloc       = tc->nursery_tospace;
    tc->nursery_alloc_limit = (char *)tc->nursery_alloc + tc->nursery_tospace_size;

    /* Set up temporary root handling. */
    tc->num_temproots   = 0;
    tc->alloc_temproots = MVM_TEMP_ROOT_BASE_ALLOC;
    tc->temproots       = MVM_malloc(sizeof(MVMCollectable **) * tc->alloc_temproots);

    /* Set up intergenerational root handling. */
    tc->num_gen2roots   = 0;
    tc->alloc_gen2roots = 64;
    tc->gen2roots       = MVM_malloc(sizeof(MVMCollectable *) * tc->alloc_gen2roots);

    /* Set up the second generation allocator. */
    tc->gen2 = MVM_gc_gen2_create(instance);

    /* The fixed size allocator also keeps pre-thread state. */
    MVM_fixed_size_create_thread(tc);

    /* Allocate an initial call stack region for the thread. */
    MVM_callstack_region_init(tc);

    /* Initialize random number generator state. */
    MVM_proc_seed(tc, (MVM_platform_now() / 10000) * MVM_proc_getpid(tc));

    /* Allocate temporary big integers. */
    for (i = 0; i < MVM_NUM_TEMP_BIGINTS; i++) {
        tc->temp_bigints[i] = MVM_malloc(sizeof(mp_int));
        mp_init(tc->temp_bigints[i]);
    }

    /* Initialize frame sequence numbers */
    tc->next_frame_nr = 0;
    tc->current_frame_nr = 0;

    /* Initialize last_payload, so we can be sure it's never NULL and don't
     * need to check. */
    tc->last_payload = instance->VMNull;

    /* Initialize plugin_guard_args so we never have to do a NULL check */
    tc->plugin_guard_args = instance->VMNull;

    /* Note that these two assignments above are repeated in
     * MVM_6model_bootstrap because VMNull doesn't exist yet when the very
     * first tc is created. */

    return tc;
}

/* Initializes a new thread context. Note that this doesn't set up a
 * thread itself, it just creates the data structure that exists in
 * MoarVM per thread. */
MVMThreadContext * MVM_tc_create(MVMThreadContext *parent, MVMInstance *instance) {
    MVMThreadContext *tc = MVM_calloc(1, sizeof(MVMThreadContext));

    /* Associate with VM instance. */
    tc->instance = instance;

    /* Use default loop for main thread; create a new one for others. */
    if (instance->main_thread) {
        int r;

        tc->loop = MVM_calloc(1, sizeof(uv_loop_t));
        r = uv_loop_init(tc->loop);
        if (r < 0) {
            MVM_free(tc->loop);
            MVM_free(tc);
            MVM_exception_throw_adhoc(parent, "Could not create a new Thread: %s", uv_strerror(r));
        }
    } else {
        tc->loop = uv_default_loop();
    }

    /* Set up GC nursery. We only allocate tospace initially, and allocate
     * fromspace the first time this thread GCs, provided it ever does. */
    tc->nursery_tospace     = MVM_calloc(1, MVM_NURSERY_SIZE);
    tc->nursery_alloc       = tc->nursery_tospace;
    tc->nursery_alloc_limit = (char *)tc->nursery_alloc + MVM_NURSERY_SIZE;

    /* Set up temporary root handling. */
    tc->num_temproots   = 0;
    tc->alloc_temproots = MVM_TEMP_ROOT_BASE_ALLOC;
    tc->temproots       = MVM_malloc(sizeof(MVMCollectable **) * tc->alloc_temproots);

    /* Set up intergenerational root handling. */
    tc->num_gen2roots   = 0;
    tc->alloc_gen2roots = 64;
    tc->gen2roots       = MVM_malloc(sizeof(MVMCollectable *) * tc->alloc_gen2roots);

    /* Set up the second generation allocator. */
    tc->gen2 = MVM_gc_gen2_create(instance);

    /* Allocate an initial call stack region for the thread. */
    MVM_callstack_region_init(tc);

    /* Initialize random number generator state. */
    MVM_proc_seed(tc, (MVM_platform_now() / 10000) * MVM_proc_getpid(tc));

    /* Initialize frame sequence numbers */
    tc->next_frame_nr = 0;
    tc->current_frame_nr = 0;

    /* Initialize last_payload, so we can be sure it's never NULL and don't
     * need to check. */
    tc->last_payload = instance->VMNull;

    return tc;
}

/* Creates a new decoding stream. */
MVMDecodeStream * MVM_string_decodestream_create(MVMThreadContext *tc, MVMint32 encoding, MVMint64 abs_byte_pos) {
    MVMDecodeStream *ds = MVM_calloc(1, sizeof(MVMDecodeStream));
    ds->encoding        = encoding;
    ds->abs_byte_pos    = abs_byte_pos;
    MVM_unicode_normalizer_init(tc, &(ds->norm), MVM_NORMALIZE_NFG);
    return ds;
}

/* Make a copy of the callsite. */
MVMCallsite * MVM_args_copy_callsite(MVMThreadContext *tc, MVMArgProcContext *ctx) {
    MVMCallsite      *res   = MVM_calloc(1, sizeof(MVMCallsite));
    MVMCallsiteEntry *flags = NULL;
    MVMCallsiteEntry *src_flags;
    MVMint32 fsize;

    if (ctx->arg_flags) {
        fsize = ctx->flag_count;
        src_flags = ctx->arg_flags;
    }
    else {
        fsize = ctx->callsite->flag_count;
        src_flags = ctx->callsite->arg_flags;
    }

    if (fsize) {
        flags = MVM_malloc(fsize * sizeof(MVMCallsiteEntry));
        memcpy(flags, src_flags, fsize * sizeof(MVMCallsiteEntry));
    }
    res->flag_count = fsize;
    res->arg_flags = flags;
    res->arg_count = ctx->arg_count;
    res->num_pos   = ctx->num_pos;
    return res;
}

void * MVM_region_alloc(MVMThreadContext *tc, MVMRegionAlloc *al, size_t bytes) {
    char *result = NULL;

#if !defined(MVM_CAN_UNALIGNED_INT64) || !defined(MVM_CAN_UNALIGNED_NUM64)
    /* Round up size to next multiple of 8, to ensure alignment. */
    bytes = (bytes + 7) & ~7;
#endif

    if (al->block != NULL && (al->block->alloc + bytes) < al->block->limit) {
        result = al->block->alloc;
        al->block->alloc += bytes;
    } else {
        /* No block, or block was full. Add another. */
        MVMRegionBlock *block = MVM_malloc(sizeof(MVMRegionBlock));
        size_t buffer_size = al->block == NULL
            ? MVM_REGIONALLOC_FIRST_MEMBLOCK_SIZE
            : MVM_REGIONALLOC_MEMBLOCK_SIZE;
        if (buffer_size < bytes)
            buffer_size = bytes;
        block->buffer = MVM_calloc(1, buffer_size);
        block->alloc  = block->buffer;
        block->limit  = block->buffer + buffer_size;
        block->prev   = al->block;
        al->block     = block;

        /* Now allocate out of it. */
        result = block->alloc;
        block->alloc += bytes;
    }
    return result;
}

/* Opens a file, returning a synchronous file handle. */
MVMObject * MVM_file_open_fh(MVMThreadContext *tc, MVMString *filename, MVMString *mode) {
    char          * const fname  = MVM_string_utf8_encode_C_string(tc, filename);
    char          * const fmode  = MVM_string_utf8_encode_C_string(tc, mode);
    MVMOSHandle   * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOFileData * const data   = MVM_calloc(1, sizeof(MVMIOFileData));
    uv_fs_t req;
    uv_file fd;

    /* Resolve mode description to flags. */
    int flag;
    if (!resolve_open_mode(&flag, fmode)) {
        char *waste[] = { fmode, NULL };
        MVM_free(fname);
        MVM_exception_throw_adhoc_free(tc, waste, "Invalid open mode: %s", fmode);
    }
    MVM_free(fmode);

    /* Try to open the file. */
    if ((fd = uv_fs_open(tc->loop, &req, (const char *)fname, flag, DEFAULT_MODE, NULL)) < 0) {
        char *waste[] = { fname, NULL };
        MVM_exception_throw_adhoc_free(tc, waste, "Failed to open file %s: %s", fname, uv_strerror(req.result));
    }

    /* Set up handle. */
    data->fd          = fd;
    data->filename    = fname;
    data->encoding    = MVM_encoding_type_utf8;
    result->body.ops  = &op_table;
    result->body.data = data;

    return (MVMObject *)result;
}

/* Log that we're entering a new frame. */
void MVM_profile_log_enter(MVMThreadContext *tc, MVMStaticFrame *sf, MVMuint64 mode) {
    MVMProfileThreadData *ptd = get_thread_data(tc);

    /* Try to locate the entry node, if it's in the call graph already. */
    MVMProfileCallNode *pcn = NULL;
    MVMuint32 i;
    if (ptd->current_call)
        for (i = 0; i < ptd->current_call->num_succ; i++)
            if (ptd->current_call->succ[i]->sf == sf)
                pcn = ptd->current_call->succ[i];

    /* If we didn't find a call graph node, then create one and add it to the
     * graph. */
    if (!pcn) {
        pcn     = MVM_calloc(1, sizeof(MVMProfileCallNode));
        pcn->sf = sf;
        if (ptd->current_call) {
            MVMProfileCallNode *pred = ptd->current_call;
            pcn->pred = pred;
            if (pred->num_succ == pred->alloc_succ) {
                pred->alloc_succ += 8;
                pred->succ = MVM_realloc(pred->succ,
                    pred->alloc_succ * sizeof(MVMProfileCallNode *));
            }
            pred->succ[pred->num_succ] = pcn;
            pred->num_succ++;
        }
        else {
            if (!ptd->call_graph)
                ptd->call_graph = pcn;
        }
    }

    /* Increment entry counts. */
    pcn->total_entries++;
    switch (mode) {
        case MVM_PROFILE_ENTER_SPESH:
            pcn->specialized_entries++;
            break;
        case MVM_PROFILE_ENTER_SPESH_INLINE:
            pcn->specialized_entries++;
            pcn->inlined_entries++;
            break;
        case MVM_PROFILE_ENTER_JIT:
            pcn->jit_entries++;
            break;
        case MVM_PROFILE_ENTER_JIT_INLINE:
            pcn->jit_entries++;
            pcn->inlined_entries++;
            break;
    }
    pcn->entry_mode = mode;

    /* Log entry time; clear skip time. */
    pcn->cur_entry_time = uv_hrtime();
    pcn->cur_skip_time  = 0;

    /* The current call graph node becomes this one. */
    ptd->current_call = pcn;
}

MVMObject * MVM_io_socket_create(MVMThreadContext *tc, MVMint64 listen) {
    MVMOSHandle         * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOSyncSocketData * const data   = MVM_calloc(1, sizeof(MVMIOSyncSocketData));
    result->body.ops  = &op_table;
    result->body.data = data;
    return (MVMObject *)result;
}

static MVMObject * socket_accept(MVMThreadContext *tc, MVMOSHandle *h) {
    MVMIOSyncSocketData *data = (MVMIOSyncSocketData *)h->body.data;
    Socket s;

    unsigned int interval_id = MVM_telemetry_interval_start(tc, "syncsocket accept");
    do {
        MVM_gc_mark_thread_blocked(tc);
        s = accept(data->handle, NULL, NULL);
        MVM_gc_mark_thread_unblocked(tc);
    } while(s == -1 && errno == EINTR);
    if (MVM_IS_SOCKET_ERROR(s)) {
        MVM_telemetry_interval_stop(tc, interval_id, "syncsocket accept failed");
        throw_error(tc, s, "accept socket connection");
    }
    else {
        MVMOSHandle * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc,
                tc->instance->boot_types.BOOTIO);
        MVMIOSyncSocketData * const data = MVM_calloc(1, sizeof(MVMIOSyncSocketData));
        data->handle = s;
        result->body.ops  = &op_table;
        result->body.data = data;
        MVM_telemetry_interval_stop(tc, interval_id, "syncsocket accept succeeded");
        return (MVMObject *)result;
    }
}

/* Allocate a piece of memory from the spesh graph's buffer. Deallocated when
 * the spesh graph is. */
void * MVM_spesh_alloc(MVMThreadContext *tc, MVMSpeshGraph *g, size_t bytes) {
    char *result = NULL;

#if !defined(MVM_CAN_UNALIGNED_INT64) || !defined(MVM_CAN_UNALIGNED_NUM64)
    /* Round up size to next multiple of 8, to ensure alignment. */
    bytes = (bytes + 7) & ~7;
#endif

    if (g->mem_block) {
        MVMSpeshMemBlock *block = g->mem_block;
        if (block->alloc + bytes < block->limit) {
            result = block->alloc;
            block->alloc += bytes;
        }
    }
    if (!result) {
        /* No block, or block was full. Add another. */
        MVMSpeshMemBlock *block = MVM_malloc(sizeof(MVMSpeshMemBlock));
        block->buffer = MVM_calloc(MVM_SPESH_MEMBLOCK_SIZE, 1);
        block->alloc  = block->buffer;
        block->limit  = block->buffer + MVM_SPESH_MEMBLOCK_SIZE;
        block->prev   = g->mem_block;
        g->mem_block  = block;

        /* Now allocate out of it. */
        if (bytes > MVM_SPESH_MEMBLOCK_SIZE) {
            MVM_spesh_graph_destroy(tc, g);
            MVM_exception_throw_adhoc(tc, "MVM_spesh_alloc: requested oversized block");
        }
        result = block->alloc;
        block->alloc += bytes;
    }
    return result;
}

/* Gets the current thread's profiling data structure, creating it if needed. */
static MVMProfileThreadData * get_thread_data(MVMThreadContext *tc) {
    if (!tc->prof_data) {
        tc->prof_data = MVM_calloc(1, sizeof(MVMProfileThreadData));
        tc->prof_data->start_time = uv_hrtime();
    }
    return tc->prof_data;
}

/* Finishes up reading and exploding of a frame. */
void MVM_bytecode_finish_frame(MVMThreadContext *tc, MVMCompUnit *cu,
                               MVMStaticFrame *sf, MVMint32 dump_only) {
    MVMuint32 j;
    MVMuint8 *pos;
    MVMuint16 slvs;

    /* Ensure we've not already done this. */
    if (sf->body.fully_deserialized)
        return;

    /* Acquire the update mutex on the CompUnit. */
    MVM_reentrantmutex_lock(tc, (MVMReentrantMutex *)cu->body.update_mutex);

    /* Ensure no other thread has done this for us in the mean time. */
    if (sf->body.fully_deserialized) {
        MVM_reentrantmutex_unlock(tc, (MVMReentrantMutex *)cu->body.update_mutex);
        return;
    }

    /* Locate start of frame body. */
    pos = sf->body.frame_data_pos;

    /* Get the number of static lex values we'll need to apply. */
    slvs = read_int16(pos, 40);

    /* Skip past header. */
    pos += FRAME_HEADER_SIZE;

    /* Read the local types. */
    if (sf->body.num_locals) {
        sf->body.local_types = MVM_malloc(sizeof(MVMuint16) * sf->body.num_locals);
        for (j = 0; j < sf->body.num_locals; j++)
            sf->body.local_types[j] = read_int16(pos, 2 * j);
        pos += 2 * sf->body.num_locals;
    }

    /* Read the lexical types. */
    if (sf->body.num_lexicals) {
        /* Allocate names hash and types list. */
        sf->body.lexical_types = MVM_malloc(sizeof(MVMuint16) * sf->body.num_lexicals);

        /* Read in data. */
        if (sf->body.num_lexicals) {
            sf->body.lexical_names_list = MVM_malloc(sizeof(MVMLexicalRegistry *) * sf->body.num_lexicals);
        }
        for (j = 0; j < sf->body.num_lexicals; j++) {
            MVMString *name = get_heap_string(tc, cu, NULL, pos, 6 * j + 2);
            MVMLexicalRegistry *entry = MVM_calloc(1, sizeof(MVMLexicalRegistry));

            MVM_ASSIGN_REF(tc, &(sf->common.header), entry->key, name);
            sf->body.lexical_names_list[j] = entry;
            entry->value = j;

            sf->body.lexical_types[j] = read_int16(pos, 6 * j);
            MVM_string_flatten(tc, name);
            MVM_HASH_BIND(tc, sf->body.lexical_names, name, entry)
        }
        pos += 6 * sf->body.num_lexicals;
    }

/* Creates the allocator data structure with bins. */
MVMFixedSizeAlloc * MVM_fixed_size_create(MVMThreadContext *tc) {
    int init_stat;
    MVMFixedSizeAlloc *al = MVM_malloc(sizeof(MVMFixedSizeAlloc));
    al->size_classes = MVM_calloc(MVM_FSA_BINS, sizeof(MVMFixedSizeAllocSizeClass));
    if ((init_stat = uv_mutex_init(&(al->complex_alloc_mutex))) < 0)
        MVM_exception_throw_adhoc(tc, "Failed to initialize mutex: %s",
                                  uv_strerror(init_stat));
    return al;
}

/* Opens a file, returning a synchronous file handle. */
MVMObject * MVM_file_handle_from_fd(MVMThreadContext *tc, uv_file fd) {
    MVMOSHandle   * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOFileData * const data   = MVM_calloc(1, sizeof(MVMIOFileData));
    data->fd          = fd;
    data->encoding    = MVM_encoding_type_utf8;
    result->body.ops  = &op_table;
    result->body.data = data;
    return (MVMObject *)result;
}

/* Wraps a libuv stream (likely, libuv pipe or TTY) up in a sync stream. */
MVMObject * MVM_io_syncstream_from_uvstream(MVMThreadContext *tc, uv_stream_t *handle) {
    MVMOSHandle         * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOSyncStreamData * const data   = MVM_calloc(1, sizeof(MVMIOSyncStreamData));
    data->handle      = handle;
    data->encoding    = MVM_encoding_type_utf8;
    data->sep         = '\n';
    result->body.ops  = &op_table;
    result->body.data = data;
    return (MVMObject *)result;
}

MVMObject * MVM_io_socket_create(MVMThreadContext *tc, MVMint64 listen) {
    MVMOSHandle         * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOSyncSocketData * const data   = MVM_calloc(1, sizeof(MVMIOSyncSocketData));
    data->ss.handle   = NULL;
    data->ss.encoding = MVM_encoding_type_utf8;
    MVM_string_decode_stream_sep_default(tc, &(data->ss.sep_spec));
    result->body.ops  = &op_table;
    result->body.data = data;
    return (MVMObject *)result;
}

/* Adds another char result buffer into the decoding stream. */
void MVM_string_decodestream_add_chars(MVMThreadContext *tc, MVMDecodeStream *ds, MVMGrapheme32 *chars, MVMint32 length) {
    MVMDecodeStreamChars *new_chars = MVM_calloc(1, sizeof(MVMDecodeStreamChars));
    new_chars->chars  = chars;
    new_chars->length = length;
    if (ds->chars_tail)
        ds->chars_tail->next = new_chars;
    ds->chars_tail = new_chars;
    if (!ds->chars_head)
        ds->chars_head = new_chars;
}

/* Creates a new decoding stream. */
MVMDecodeStream * MVM_string_decodestream_create(MVMThreadContext *tc, MVMint32 encoding,
        MVMint64 abs_byte_pos, MVMint32 translate_newlines) {
    MVMDecodeStream *ds = MVM_calloc(1, sizeof(MVMDecodeStream));
    ds->encoding        = encoding;
    ds->abs_byte_pos    = abs_byte_pos;
    MVM_unicode_normalizer_init(tc, &(ds->norm), MVM_NORMALIZE_NFG);
    if (translate_newlines)
        MVM_unicode_normalizer_translate_newlines(tc, &(ds->norm));
    ds->result_size_guess = 64;
    return ds;
}

/* Opens a file, returning a synchronous file handle. */
MVMObject * MVM_file_open_fh(MVMThreadContext *tc, MVMString *filename, MVMString *mode) {
    char * const fname = MVM_string_utf8_c8_encode_C_string(tc, filename);
    int fd;
    int flag;
    STAT statbuf;

    /* Resolve mode description to flags. */
    char * const fmode  = MVM_string_utf8_encode_C_string(tc, mode);
    if (!resolve_open_mode(&flag, fmode)) {
        char *waste[] = { fname, fmode, NULL };
        MVM_exception_throw_adhoc_free(tc, waste,
            "Invalid open mode for file %s: %s", fname, fmode);
    }
    MVM_free(fmode);

    /* Try to open the file. */
#ifdef _WIN32
    flag |= _O_BINARY;
#endif
    if ((fd = open((const char *)fname, flag, DEFAULT_MODE)) == -1) {
        char *waste[] = { fname, NULL };
        const char *err = strerror(errno);
        MVM_exception_throw_adhoc_free(tc, waste, "Failed to open file %s: %s", fname, err);
    }

    /*  Check that we didn't open a directory by accident.
        If fstat fails, just move on: Most of the documented error cases should
        already have triggered when opening the file, and we can't do anything
        about the others; a failure also does not necessarily imply that the
        file descriptor cannot be used for reading/writing. */
    if (fstat(fd, &statbuf) == 0 && (statbuf.st_mode & S_IFMT) == S_IFDIR) {
        char *waste[] = { fname, NULL };
        if (close(fd) == -1) {
            const char *err = strerror(errno);
            MVM_exception_throw_adhoc_free(tc, waste,
                "Tried to open directory %s, which we failed to close: %s",
                fname, err);
        }
        MVM_exception_throw_adhoc_free(tc, waste, "Tried to open directory %s", fname);
    }

    /* Set up handle. */
    MVM_free(fname);
    {
        MVMIOFileData * const data   = MVM_calloc(1, sizeof(MVMIOFileData));
        MVMOSHandle   * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc,
            tc->instance->boot_types.BOOTIO);
        data->fd          = fd;
        data->seekable    = MVM_platform_lseek(fd, 0, SEEK_CUR) != -1;
        result->body.ops  = &op_table;
        result->body.data = data;
        return (MVMObject *)result;
    }
}

/* Opens a file, returning a synchronous file handle. */
MVMObject * MVM_file_handle_from_fd(MVMThreadContext *tc, int fd) {
    MVMOSHandle   * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);
    MVMIOFileData * const data   = MVM_calloc(1, sizeof(MVMIOFileData));
    data->fd          = fd;
    data->seekable    = MVM_platform_lseek(fd, 0, SEEK_CUR) != -1;
    result->body.ops  = &op_table;
    result->body.data = data;
#ifdef _WIN32
    _setmode(fd, _O_BINARY);
#endif
    return (MVMObject *)result;
}