#include "moar.h"

#ifndef _WIN32

    #include <sys/wait.h>

#endif

/* This heavily re-uses the logic from syncstream, but with different close

 * and gc_free semantics. */

/* Closes the pipe. */

static MVMint64 do_close(MVMThreadContext *tc, MVMIOSyncPipeData *data) {

#ifdef _WIN32

    DWORD status = 0;

#else

    int status = 0;

#endif

    if (!data) return 0;

    if (data->ss.handle == NULL || uv_is_closing((uv_handle_t*)data->ss.handle))

        return 0;

    /* closing the in-/output std filehandle will shutdown the child process. */

    uv_unref((uv_handle_t*)data->ss.handle);

    uv_close((uv_handle_t*)data->ss.handle, NULL);

    if (data->process) {

#ifdef _WIN32

        if (!uv_is_closing((uv_handle_t*)data->process))

            uv_process_close(tc->loop, data->process);

        GetExitCodeProcess(data->process->process_handle, &status);

        status = status << 8;

#else

        pid_t wpid;

        do

            wpid = waitpid(data->process->pid, &status, 0);

        while (wpid == -1 && errno == EINTR);

#endif

    }

    if (!status && data->process->data) {

        status = *(MVMint64*)data->process->data;

        MVM_free(data->process->data);

        data->process->data = NULL;

    }

    uv_unref((uv_handle_t *)data->process);

    uv_run(tc->loop, UV_RUN_DEFAULT);

    data->process   = NULL;

    data->ss.handle = NULL;

    MVM_free(data);

    return (MVMint64)status;

}

static MVMint64 closefh(MVMThreadContext *tc, MVMOSHandle *h) {

    MVMIOSyncPipeData *data = (MVMIOSyncPipeData *)h->body.data;

    h->body.data = NULL; /* data will be freed by do_close */

    return do_close(tc, data);

}

/* Operations aiding process spawning and I/O handling. */

static void bind_stdio_handle(MVMThreadContext *tc, MVMOSHandle *h, uv_stdio_container_t *stdio) {

    MVMIOSyncPipeData *data = (MVMIOSyncPipeData *)h->body.data;

    stdio->flags            = UV_INHERIT_STREAM;

    stdio->data.stream      = data->ss.handle;

}

/* Frees data associated with the pipe, closing it if needed. */

static void gc_free(MVMThreadContext *tc, MVMObject *h, void *d) {

    MVMIOSyncPipeData *data = (MVMIOSyncPipeData *)d;

    do_close(tc, data);

}

/* Get native file descriptor. */

static MVMint64 mvm_fileno(MVMThreadContext *tc, MVMOSHandle *h) {

    MVMIOSyncPipeData *data = (MVMIOSyncPipeData *)h->body.data;

    uv_os_fd_t fd;

    if (uv_fileno((uv_handle_t *)data->ss.handle, &fd) >= 0)

        return (MVMint64)fd;

    return -1;

}

/* IO ops table, populated with functions. */

static const MVMIOClosable     closable      = { closefh };

static const MVMIOSyncReadable sync_readable = { MVM_io_syncstream_read_bytes,

                                                 MVM_io_syncstream_eof };

static const MVMIOSyncWritable sync_writable = { MVM_io_syncstream_write_bytes,

                                                 MVM_io_syncstream_flush,

                                                 MVM_io_syncstream_truncate };

static const MVMIOSeekable          seekable = { MVM_io_syncstream_seek,

                                                 MVM_io_syncstream_tell };

static const MVMIOPipeable     pipeable      = { bind_stdio_handle };

static const MVMIOIntrospection introspection = { NULL, mvm_fileno };

static const MVMIOOps op_table = {

    &closable,

    &sync_readable,

    &sync_writable,

    NULL,

    NULL,

    NULL,

    &seekable,

    NULL,

    &pipeable,

    NULL,

    &introspection,

    NULL,

    NULL,

    gc_free

};

/* Creates a sync pipe handle. */

MVMObject * MVM_io_syncpipe(MVMThreadContext *tc) {

    MVMOSHandle       * const result = (MVMOSHandle *)MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTIO);

    MVMIOSyncPipeData * const data   = MVM_calloc(1, sizeof(MVMIOSyncPipeData));

    uv_pipe_t *handle = MVM_malloc(sizeof(uv_pipe_t));

    uv_pipe_init(tc->loop, handle, 0);

    data->ss.handle   = (uv_stream_t *)handle;

    result->body.ops  = &op_table;

    result->body.data = data;

    return (MVMObject *)result;

}