/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Paul Sokolovsky
 * Copyright (c) Quectel Wireless Solution, Co., Ltd.All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "py/runtime.h"
#include "py/stream.h"
#include "extmod/moduwebsocket.h"

#if MICROPY_PY_UWEBSOCKET

enum { FRAME_HEADER, FRAME_OPT, PAYLOAD, CONTROL };

enum { BLOCKING_WRITE = 0x80 };

typedef struct _mp_obj_websocket_t {
 mp_obj_base_t base;
 mp_obj_t sock;
 uint32_t msg_sz;
 byte mask[4];
 byte state;
 byte to_recv;
 byte mask_pos;
 byte buf_pos;
 byte buf[6];
 byte opts;
 // Copy of last data frame flags
 byte ws_flags;
 // Copy of current frame flags
 byte last_flags;
} mp_obj_websocket_t;

STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode);

STATIC mp_obj_t websocket_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 mp_arg_check_num(n_args, n_kw, 1, 2, false);
 mp_get_stream_raise(args[0], MP_STREAM_OP_READ | MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
 mp_obj_websocket_t *o = m_new_obj(mp_obj_websocket_t);
 o->base.type = type;
 o->sock = args[0];
 o->state = FRAME_HEADER;
 o->to_recv = 2;
 o->mask_pos = 0;
 o->buf_pos = 0;
 o->opts = FRAME_TXT;
 if (n_args > 1 && args[1] == mp_const_true) {
 o->opts |= BLOCKING_WRITE;
 }
 return MP_OBJ_FROM_PTR(o);
}

STATIC mp_uint_t websocket_read(mp_obj_t self_in, void *buf, mp_uint_t size, int *errcode) {
 mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
 const mp_stream_p_t *stream_p = mp_get_stream(self->sock);
 while (1) {
 if (self->to_recv != 0) {
 mp_uint_t out_sz = stream_p->read(self->sock, self->buf + self->buf_pos, self->to_recv, errcode);
 if (out_sz == 0 || out_sz == MP_STREAM_ERROR) {
 return out_sz;
 }
 self->buf_pos += out_sz;
 self->to_recv -= out_sz;
 if (self->to_recv != 0) {
 *errcode = MP_EAGAIN;
 return MP_STREAM_ERROR;
 }
 }

 switch (self->state) {
 case FRAME_HEADER: {
 // TODO: Split frame handling below is untested so far, so conservatively disable it
 assert(self->buf[0] & 0x80);

 // "Control frames MAY be injected in the middle of a fragmented message."
 // So, they must be processed before data frames (and not alter
 // self->ws_flags)
 byte frame_type = self->buf[0];
 self->last_flags = frame_type;
 frame_type &= FRAME_OPCODE_MASK;

 if ((self->buf[0] & FRAME_OPCODE_MASK) == FRAME_CONT) {
 // Preserve previous frame type
 self->ws_flags = (self->ws_flags & FRAME_OPCODE_MASK) | (self->buf[0] & ~FRAME_OPCODE_MASK);
 } else {
 self->ws_flags = self->buf[0];
 }

 // Reset mask in case someone will use "simplified" protocol
 // without masks.
 memset(self->mask, 0, sizeof(self->mask));

 int to_recv = 0;
 size_t sz = self->buf[1] & 0x7f;
 if (sz == 126) {
 // Msg size is next 2 bytes
 to_recv += 2;
 } else if (sz == 127) {
 // Msg size is next 8 bytes
 assert(0);
 }
 if (self->buf[1] & 0x80) {
 // Next 4 bytes is mask
 to_recv += 4;
 }

 self->buf_pos = 0;
 self->to_recv = to_recv;
 self->msg_sz = sz; // May be overridden by FRAME_OPT
 if (to_recv != 0) {
 self->state = FRAME_OPT;
 } else {
 if (frame_type >= FRAME_CLOSE) {
 self->state = CONTROL;
 } else {
 self->state = PAYLOAD;
 }
 }
 continue;
 }

 case FRAME_OPT: {
 if ((self->buf_pos & 3) == 2) {
 // First two bytes are message length
 self->msg_sz = (self->buf[0] << 8) | self->buf[1];
 }
 if (self->buf_pos >= 4) {
 // Last 4 bytes is mask
 memcpy(self->mask, self->buf + self->buf_pos - 4, 4);
 }
 self->buf_pos = 0;
 if ((self->last_flags & FRAME_OPCODE_MASK) >= FRAME_CLOSE) {
 self->state = CONTROL;
 } else {
 self->state = PAYLOAD;
 }
 continue;
 }

 case PAYLOAD:
 case CONTROL: {
 mp_uint_t out_sz = 0;
 if (self->msg_sz == 0) {
 // In case message had zero payload
 goto no_payload;
 }

 size_t sz = MIN(size, self->msg_sz);
 out_sz = stream_p->read(self->sock, buf, sz, errcode);
 if (out_sz == 0 || out_sz == MP_STREAM_ERROR) {
 return out_sz;
 }

 sz = out_sz;
 for (byte *p = buf; sz--; p++) {
 *p ^= self->mask[self->mask_pos++ & 3];
 }

 self->msg_sz -= out_sz;
 if (self->msg_sz == 0) {
 byte last_state;
 no_payload:
 last_state = self->state;
 self->state = FRAME_HEADER;
 self->to_recv = 2;
 self->mask_pos = 0;
 self->buf_pos = 0;

 // Handle control frame
 if (last_state == CONTROL) {
 byte frame_type = self->last_flags & FRAME_OPCODE_MASK;
 if (frame_type == FRAME_CLOSE) {
 static const char close_resp[2] = {0x88, 0};
 int err;
 websocket_write(self_in, close_resp, sizeof(close_resp), &err);
 return 0;
 }

 // DEBUG_printf("Finished receiving ctrl message %x, ignoring\n", self->last_flags);
 continue;
 }
 }

 if (out_sz != 0) {
 return out_sz;
 }
 // Empty (data) frame received is not EOF
 continue;
 }

 }
 }
}

STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
 mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
 assert(size < 0x10000);
 byte header[4] = {0x80 | (self->opts & FRAME_OPCODE_MASK)};
 int hdr_sz;
 if (size < 126) {
 header[1] = size;
 hdr_sz = 2;
 } else {
 header[1] = 126;
 header[2] = size >> 8;
 header[3] = size & 0xff;
 hdr_sz = 4;
 }

 mp_obj_t dest[3];
 if (self->opts & BLOCKING_WRITE) {
 mp_load_method(self->sock, MP_QSTR_setblocking, dest);
 dest[2] = mp_const_true;
 mp_call_method_n_kw(1, 0, dest);
 }

 mp_uint_t out_sz = mp_stream_write_exactly(self->sock, header, hdr_sz, errcode);
 if (*errcode == 0) {
 out_sz = mp_stream_write_exactly(self->sock, buf, size, errcode);
 }

 if (self->opts & BLOCKING_WRITE) {
 dest[2] = mp_const_false;
 mp_call_method_n_kw(1, 0, dest);
 }

 if (*errcode != 0) {
 return MP_STREAM_ERROR;
 }
 return out_sz;
}

STATIC mp_uint_t websocket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
 mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
 switch (request) {
 case MP_STREAM_CLOSE:
 // TODO: Send close signaling to the other side, otherwise it's
 // abrupt close (connection abort).
 mp_stream_close(self->sock);
 return 0;
 case MP_STREAM_GET_DATA_OPTS:
 return self->ws_flags & FRAME_OPCODE_MASK;
 case MP_STREAM_SET_DATA_OPTS: {
 int cur = self->opts & FRAME_OPCODE_MASK;
 self->opts = (self->opts & ~FRAME_OPCODE_MASK) | (arg & FRAME_OPCODE_MASK);
 return cur;
 }
 default:
 *errcode = MP_EINVAL;
 return MP_STREAM_ERROR;
 }
}

STATIC const mp_rom_map_elem_t websocket_locals_dict_table[] = {
 { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
 { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
 { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
 { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
 { MP_ROM_QSTR(MP_QSTR_ioctl), MP_ROM_PTR(&mp_stream_ioctl_obj) },
 { MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&mp_stream_close_obj) },
};
STATIC MP_DEFINE_CONST_DICT(websocket_locals_dict, websocket_locals_dict_table);

STATIC const mp_stream_p_t websocket_stream_p = {
 .read = websocket_read,
 .write = websocket_write,
 .ioctl = websocket_ioctl,
};

STATIC const mp_obj_type_t websocket_type = {
 { &mp_type_type },
 .name = MP_QSTR_websocket,
 .make_new = websocket_make_new,
 .protocol = &websocket_stream_p,
 .locals_dict = (void *)&websocket_locals_dict,
};

STATIC const mp_rom_map_elem_t uwebsocket_module_globals_table[] = {
 { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_uwebsocket) },
 { MP_ROM_QSTR(MP_QSTR_websocket), MP_ROM_PTR(&websocket_type) },
};

STATIC MP_DEFINE_CONST_DICT(uwebsocket_module_globals, uwebsocket_module_globals_table);

const mp_obj_module_t mp_module_uwebsocket = {
 .base = { &mp_type_module },
 .globals = (mp_obj_dict_t *)&uwebsocket_module_globals,
};

#endif // MICROPY_PY_UWEBSOCKET