/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2022 Greg Davill
 * Copyright (c) 2023 Denis Krasutski
 *
 * 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.
 *
 * This file is part of the TinyUSB stack.
 */

#include "tusb_option.h"

#if CFG_TUD_ENABLED && defined(TUP_USBIP_WCH_USBHS) && CFG_TUD_WCH_USBIP_USBHS
#include "ch32_usbhs_reg.h"

#include "device/dcd.h"

// Max number of bi-directional endpoints including EP0
#define EP_MAX  16

typedef struct {
  uint8_t* buffer;
  uint16_t total_len;
  uint16_t queued_len;
  uint16_t max_size;
  bool is_last_packet;
  bool is_iso;
} xfer_ctl_t;

typedef enum {
  EP_RESPONSE_ACK,
  EP_RESPONSE_NAK,
} ep_response_list_t;

#define XFER_CTL_BASE(_ep, _dir) &xfer_status[_ep][_dir]
static xfer_ctl_t xfer_status[EP_MAX][2];

#define EP_TX_LEN(ep)     *(volatile uint16_t *)((volatile uint16_t *)&(USBHSD->UEP0_TX_LEN) + (ep) * 2)
#define EP_TX_CTRL(ep)    *(volatile uint8_t *)((volatile uint8_t *)&(USBHSD->UEP0_TX_CTRL) + (ep) * 4)
#define EP_RX_CTRL(ep)    *(volatile uint8_t *)((volatile uint8_t *)&(USBHSD->UEP0_RX_CTRL) + (ep) * 4)
#define EP_RX_MAX_LEN(ep) *(volatile uint16_t *)((volatile uint16_t *)&(USBHSD->UEP0_MAX_LEN) + (ep) * 2)

#define EP_TX_DMA_ADDR(ep) *(volatile uint32_t *)((volatile uint32_t *)&(USBHSD->UEP1_TX_DMA) + (ep - 1))
#define EP_RX_DMA_ADDR(ep) *(volatile uint32_t *)((volatile uint32_t *)&(USBHSD->UEP1_RX_DMA) + (ep - 1))

/* Endpoint Buffer */
TU_ATTR_ALIGNED(4) static uint8_t ep0_buffer[CFG_TUD_ENDPOINT0_SIZE];

static void ep_set_response_and_toggle(uint8_t ep_num, tusb_dir_t ep_dir, ep_response_list_t response_type) {
  if (ep_dir == TUSB_DIR_IN) {
    uint8_t response = (response_type == EP_RESPONSE_ACK) ? USBHS_EP_T_RES_ACK : USBHS_EP_T_RES_NAK;
    if (ep_num == 0) {
      if (response_type == EP_RESPONSE_ACK) {
        if (EP_TX_LEN(ep_num) == 0) {
          EP_TX_CTRL(ep_num) |= USBHS_EP_T_TOG_1;
        } else {
          EP_TX_CTRL(ep_num) ^= USBHS_EP_T_TOG_1;
        }
      }
    }
    if (xfer_status[ep_num][TUSB_DIR_IN].is_iso == true) {
      EP_TX_CTRL(ep_num) = USBHS_EP_T_AUTOTOG;
    } else {
      EP_TX_CTRL(ep_num) = (EP_TX_CTRL(ep_num) & ~(USBHS_EP_T_RES_MASK)) | response;
    }
  } else {
    uint8_t response = (response_type == EP_RESPONSE_ACK) ? USBHS_EP_R_RES_ACK : USBHS_EP_R_RES_NAK;
    if (ep_num == 0) {
      if (response_type == EP_RESPONSE_ACK) {
        if (xfer_status[ep_num][TUSB_DIR_OUT].queued_len == 0) {
          EP_RX_CTRL(ep_num) |= USBHS_EP_R_TOG_1;
        }
      } else {
        EP_RX_CTRL(ep_num) ^= USBHS_EP_R_TOG_1;
      }
    }
    EP_RX_CTRL(ep_num) = (EP_RX_CTRL(ep_num) & ~(USBHS_EP_R_RES_MASK)) | response;
  }
}

static void xfer_data_packet(uint8_t ep_num, tusb_dir_t ep_dir, xfer_ctl_t* xfer) {
  if (ep_dir == TUSB_DIR_IN) {
    uint16_t remaining = xfer->total_len - xfer->queued_len;
    uint16_t next_tx_size = TU_MIN(remaining, xfer->max_size);

    if (ep_num == 0) {
      memcpy(ep0_buffer, &xfer->buffer[xfer->queued_len], next_tx_size);
    } else {
      EP_TX_DMA_ADDR(ep_num) = (uint32_t) &xfer->buffer[xfer->queued_len];
    }

    EP_TX_LEN(ep_num) = next_tx_size;
    xfer->queued_len += next_tx_size;
    if (xfer->queued_len == xfer->total_len) {
      xfer->is_last_packet = true;
    }
    if (xfer->is_iso == true) {
      /* Enable EP to generate ISA_ACT interrupt */
      USBHSD->ENDP_CONFIG |= (USBHS_EP0_T_EN << ep_num);
    }
  } else { /* TUSB_DIR_OUT */
    uint16_t left_to_receive = xfer->total_len - xfer->queued_len;
    uint16_t max_possible_rx_size = TU_MIN(xfer->max_size, left_to_receive);

    if (max_possible_rx_size == left_to_receive) {
      xfer->is_last_packet = true;
    }

    if (ep_num > 0) {
      EP_RX_DMA_ADDR(ep_num) = (uint32_t) &xfer->buffer[xfer->queued_len];
      EP_RX_MAX_LEN(ep_num) = max_possible_rx_size;
    }
  }
  ep_set_response_and_toggle(ep_num, ep_dir, USBHS_EP_R_RES_ACK);
}

void dcd_init(uint8_t rhport, const tusb_rhport_init_t* rh_init) {
  (void) rhport;
  (void) rh_init;

  memset(&xfer_status, 0, sizeof(xfer_status));

  USBHSD->HOST_CTRL = 0x00;
  USBHSD->HOST_CTRL = USBHS_PHY_SUSPENDM;

  USBHSD->CONTROL = 0;

#if TUD_OPT_HIGH_SPEED
  USBHSD->CONTROL = USBHS_DMA_EN | USBHS_INT_BUSY_EN | USBHS_HIGH_SPEED;
#else
  #error OPT_MODE_FULL_SPEED not currently supported on CH32
  USBHSD->CONTROL = USBHS_DMA_EN | USBHS_INT_BUSY_EN | USBHS_FULL_SPEED;
#endif

  USBHSD->INT_EN = 0;
  USBHSD->INT_EN = USBHS_SETUP_ACT_EN | USBHS_TRANSFER_EN | USBHS_BUS_RST_EN | USBHS_SUSPEND_EN | USBHS_ISO_ACT_EN;

  USBHSD->ENDP_CONFIG = USBHS_EP0_T_EN | USBHS_EP0_R_EN;
  USBHSD->ENDP_TYPE = 0x00;
  USBHSD->BUF_MODE = 0x00;

  for (int ep = 0; ep < EP_MAX; ep++) {
    EP_TX_LEN(ep) = 0;
    EP_TX_CTRL(ep) = USBHS_EP_T_AUTOTOG | USBHS_EP_T_RES_NAK;
    EP_RX_CTRL(ep) = USBHS_EP_R_AUTOTOG | USBHS_EP_R_RES_NAK;

    EP_RX_MAX_LEN(ep) = 0;
  }

  USBHSD->UEP0_DMA = (uint32_t) ep0_buffer;
  USBHSD->UEP0_MAX_LEN = CFG_TUD_ENDPOINT0_SIZE;
  xfer_status[0][TUSB_DIR_OUT].max_size = CFG_TUD_ENDPOINT0_SIZE;
  xfer_status[0][TUSB_DIR_IN].max_size = CFG_TUD_ENDPOINT0_SIZE;

  USBHSD->DEV_AD = 0;
  USBHSD->CONTROL |= USBHS_DEV_PU_EN;
}

void dcd_int_enable(uint8_t rhport) {
  (void) rhport;
  NVIC_EnableIRQ(USBHS_IRQn);
}

void dcd_int_disable(uint8_t rhport) {
  (void) rhport;
  NVIC_DisableIRQ(USBHS_IRQn);
}

void dcd_edpt_close_all(uint8_t rhport) {
  (void) rhport;

  for (size_t ep = 1; ep < EP_MAX; ep++) {
    EP_TX_LEN(ep) = 0;
    EP_TX_CTRL(ep) = USBHS_EP_T_AUTOTOG | USBHS_EP_T_RES_NAK;
    EP_RX_CTRL(ep) = USBHS_EP_R_AUTOTOG | USBHS_EP_R_RES_NAK;

    EP_RX_MAX_LEN(ep) = 0;
  }

  USBHSD->ENDP_CONFIG = USBHS_EP0_T_EN | USBHS_EP0_R_EN;
}

void dcd_set_address(uint8_t rhport, uint8_t dev_addr) {
  (void) dev_addr;

  // Response with zlp status
  dcd_edpt_xfer(rhport, 0x80, NULL, 0);
}

void dcd_remote_wakeup(uint8_t rhport) {
  (void) rhport;
}

void dcd_sof_enable(uint8_t rhport, bool en) {
  (void) rhport;
  if (en) {
    USBHSD->INT_EN |= USBHS_SOF_ACT_EN;
  } else {
    USBHSD->INT_EN &= ~(USBHS_SOF_ACT_EN);
  }
}

void dcd_edpt0_status_complete(uint8_t rhport, tusb_control_request_t const* request) {
  (void) rhport;

  if (request->bmRequestType_bit.recipient == TUSB_REQ_RCPT_DEVICE &&
      request->bmRequestType_bit.type == TUSB_REQ_TYPE_STANDARD &&
      request->bRequest == TUSB_REQ_SET_ADDRESS) {
    USBHSD->DEV_AD = (uint8_t) request->wValue;
  }

  EP_TX_CTRL(0) = USBHS_EP_T_RES_NAK | USBHS_EP_T_TOG_0;
  EP_RX_CTRL(0) = USBHS_EP_R_RES_NAK | USBHS_EP_R_TOG_0;
}

bool dcd_edpt_open(uint8_t rhport, tusb_desc_endpoint_t const* desc_edpt) {
  (void) rhport;

  uint8_t const ep_num = tu_edpt_number(desc_edpt->bEndpointAddress);
  tusb_dir_t const dir = tu_edpt_dir(desc_edpt->bEndpointAddress);

  TU_ASSERT(ep_num < EP_MAX);

  if (ep_num == 0) {
    return true;
  }

  xfer_ctl_t* xfer = XFER_CTL_BASE(ep_num, dir);
  xfer->max_size = tu_edpt_packet_size(desc_edpt);

  xfer->is_iso = (desc_edpt->bmAttributes.xfer == TUSB_XFER_ISOCHRONOUS);
  if (dir == TUSB_DIR_OUT) {
    USBHSD->ENDP_CONFIG |= (USBHS_EP0_R_EN << ep_num);
    EP_RX_CTRL(ep_num) = USBHS_EP_R_AUTOTOG | USBHS_EP_R_RES_NAK;
    if (xfer->is_iso == true) {
      USBHSD->ENDP_TYPE |= (USBHS_EP0_R_TYP << ep_num);
    }
    EP_RX_MAX_LEN(ep_num) = xfer->max_size;
  } else {
    if (xfer->is_iso == true) {
      USBHSD->ENDP_TYPE |= (USBHS_EP0_T_TYP << ep_num);
    } else {
      /* Enable all types except Isochronous to avoid ISO_ACT interrupt generation */
      USBHSD->ENDP_CONFIG |= (USBHS_EP0_T_EN << ep_num);
    }
    EP_TX_LEN(ep_num) = 0;
    EP_TX_CTRL(ep_num) = USBHS_EP_T_AUTOTOG | USBHS_EP_T_RES_NAK | USBHS_EP_T_TOG_0;
  }

  return true;
}

void dcd_edpt_close(uint8_t rhport, uint8_t ep_addr) {
  (void) rhport;

  uint8_t const ep_num = tu_edpt_number(ep_addr);
  tusb_dir_t const dir = tu_edpt_dir(ep_addr);

  if (dir == TUSB_DIR_OUT) {
    EP_RX_CTRL(ep_num) = USBHS_EP_R_AUTOTOG | USBHS_EP_R_RES_NAK;
    EP_RX_MAX_LEN(ep_num) = 0;
    USBHSD->ENDP_TYPE &= ~(USBHS_EP0_R_TYP << ep_num);
    USBHSD->ENDP_CONFIG &= ~(USBHS_EP0_R_EN << ep_num);
  } else {  // TUSB_DIR_IN
    EP_TX_CTRL(ep_num) = USBHS_EP_T_AUTOTOG | USBHS_EP_T_RES_NAK | USBHS_EP_T_TOG_0;
    EP_TX_LEN(ep_num) = 0;
    USBHSD->ENDP_TYPE &= ~(USBHS_EP0_T_TYP << ep_num);
    USBHSD->ENDP_CONFIG &= ~(USBHS_EP0_T_EN << ep_num);
  }
}

void dcd_edpt_stall(uint8_t rhport, uint8_t ep_addr) {
  (void) rhport;

  uint8_t const ep_num = tu_edpt_number(ep_addr);
  tusb_dir_t const dir = tu_edpt_dir(ep_addr);

  if (dir == TUSB_DIR_OUT) {
    EP_RX_CTRL(ep_num) = USBHS_EP_R_RES_STALL;
  } else {
    EP_TX_LEN(0) = 0;
    EP_TX_CTRL(ep_num) = USBHS_EP_T_RES_STALL;
  }
}

void dcd_edpt_clear_stall(uint8_t rhport, uint8_t ep_addr) {
  (void) rhport;

  uint8_t const ep_num = tu_edpt_number(ep_addr);
  tusb_dir_t const dir = tu_edpt_dir(ep_addr);

  if (dir == TUSB_DIR_OUT) {
    EP_RX_CTRL(ep_num) = USBHS_EP_R_AUTOTOG | USBHS_EP_R_RES_NAK;
  } else {
    EP_TX_CTRL(ep_num) = USBHS_EP_T_AUTOTOG | USBHS_EP_R_RES_NAK;
  }
}

bool dcd_edpt_xfer(uint8_t rhport, uint8_t ep_addr, uint8_t* buffer, uint16_t total_bytes) {
  (void) rhport;
  uint8_t const ep_num = tu_edpt_number(ep_addr);
  tusb_dir_t const dir = tu_edpt_dir(ep_addr);

  xfer_ctl_t* xfer = XFER_CTL_BASE(ep_num, dir);
  xfer->buffer = buffer;
  xfer->total_len = total_bytes;
  xfer->queued_len = 0;
  xfer->is_last_packet = false;

  xfer_data_packet(ep_num, dir, xfer);

  return true;
}

void dcd_int_handler(uint8_t rhport) {
  (void) rhport;

  uint8_t int_flag = USBHSD->INT_FG;
  uint8_t int_status = USBHSD->INT_ST;

  if (int_flag & (USBHS_ISO_ACT_FLAG | USBHS_TRANSFER_FLAG)) {
    uint8_t const token = int_status & MASK_UIS_TOKEN;

    if (token == USBHS_TOKEN_PID_SOF) {
      uint32_t frame_count = USBHSD->FRAME_NO & USBHS_FRAME_NO_NUM_MASK;
      dcd_event_sof(rhport, frame_count, true);
    }else {
      uint8_t const ep_num = int_status & MASK_UIS_ENDP;
      tusb_dir_t const ep_dir = (token == USBHS_TOKEN_PID_IN) ? TUSB_DIR_IN : TUSB_DIR_OUT;
      uint8_t const ep_addr = tu_edpt_addr(ep_num, ep_dir);
      xfer_ctl_t* xfer = XFER_CTL_BASE(ep_num, ep_dir);

      if (token == USBHS_TOKEN_PID_OUT) {
        uint16_t rx_len = USBHSD->RX_LEN;

        if (ep_num == 0) {
          memcpy(&xfer->buffer[xfer->queued_len], ep0_buffer, rx_len);
        }

        xfer->queued_len += rx_len;
        if (rx_len < xfer->max_size) {
          xfer->is_last_packet = true;
        }
      } else if (token == USBHS_TOKEN_PID_IN) {
        if (xfer->is_iso && xfer->is_last_packet) {
          /* Disable EP to avoid ISO_ACT interrupt generation */
          USBHSD->ENDP_CONFIG &= ~(USBHS_EP0_T_EN << ep_num);
        } else {
          // Do nothing, no need to update xfer->is_last_packet, it is already updated in xfer_data_packet
        }
      }

      if (xfer->is_last_packet == true) {
        ep_set_response_and_toggle(ep_num, ep_dir, EP_RESPONSE_NAK);
        dcd_event_xfer_complete(0, ep_addr, xfer->queued_len, XFER_RESULT_SUCCESS, true);
      } else {
        /* prepare next part of packet to xref */
        xfer_data_packet(ep_num, ep_dir, xfer);
      }
    }

    USBHSD->INT_FG = (int_flag & (USBHS_ISO_ACT_FLAG | USBHS_TRANSFER_FLAG)); /* Clear flag */
  } else if (int_flag & USBHS_SETUP_FLAG) {
    ep_set_response_and_toggle(0, TUSB_DIR_IN, EP_RESPONSE_NAK);
    ep_set_response_and_toggle(0, TUSB_DIR_OUT, EP_RESPONSE_NAK);
    dcd_event_setup_received(0, ep0_buffer, true);

    USBHSD->INT_FG = USBHS_SETUP_FLAG; /* Clear flag */
  } else if (int_flag & USBHS_BUS_RST_FLAG) {
    // TODO CH32 does not detect actual speed at this time (should be known at end of reset)
    // This interrupt probably triggered at start of bus reset
//    tusb_speed_t actual_speed;
//    switch(USBHSD->SPEED_TYPE & USBHS_SPEED_TYPE_MASK){
//      case USBHS_SPEED_TYPE_HIGH:
//        actual_speed = TUSB_SPEED_HIGH;
//        break;
//      case USBHS_SPEED_TYPE_FULL:
//        actual_speed = TUSB_SPEED_FULL;
//        break;
//      case USBHS_SPEED_TYPE_LOW:
//        actual_speed = TUSB_SPEED_LOW;
//        break;
//      default:
//        TU_ASSERT(0,);
//        break;
//    }
//    dcd_event_bus_reset(0, actual_speed, true);

    dcd_event_bus_reset(0, TUSB_SPEED_HIGH, true);

    USBHSD->DEV_AD = 0;
    EP_RX_CTRL(0) = USBHS_EP_R_RES_ACK | USBHS_EP_R_TOG_0;
    EP_TX_CTRL(0) = USBHS_EP_T_RES_NAK | USBHS_EP_T_TOG_0;

    USBHSD->INT_FG = USBHS_BUS_RST_FLAG; /* Clear flag */
  } else if (int_flag & USBHS_SUSPEND_FLAG) {
    dcd_event_t event = {.rhport = rhport, .event_id = DCD_EVENT_SUSPEND};
    dcd_event_handler(&event, true);

    USBHSD->INT_FG = USBHS_SUSPEND_FLAG; /* Clear flag */
  }
}

#endif