/******************************************************************************
 *
 *  Copyright 2004-2012 Broadcom Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/******************************************************************************
 *
 *  This file contains the PAN main functions and state machine.
 *
 ******************************************************************************/
#include <bluetooth/log.h>

#include <cstddef>
#include <cstdint>
#include <cstring>

#include "bta/pan/bta_pan_int.h"
#include "bta_pan_api.h"
#include "osi/include/fixed_queue.h"
#include "stack/include/bt_hdr.h"

using namespace bluetooth;

/*****************************************************************************
 * Constants and types
 ****************************************************************************/

/* state machine action enumeration list */
enum {
  BTA_PAN_API_CLOSE,
  BTA_PAN_TX_PATH,
  BTA_PAN_RX_PATH,
  BTA_PAN_TX_FLOW,
  BTA_PAN_WRITE_BUF,
  BTA_PAN_CONN_OPEN,
  BTA_PAN_CONN_CLOSE,
  BTA_PAN_FREE_BUF,
  BTA_PAN_IGNORE,
  BTA_PAN_MAX_ACTIONS
};

/* type for action functions */
typedef void (*tBTA_PAN_ACTION)(tBTA_PAN_SCB* p_scb, tBTA_PAN_DATA* p_data);

/* action function list */
const tBTA_PAN_ACTION bta_pan_action[] = {
        bta_pan_api_close, bta_pan_tx_path,   bta_pan_rx_path,    bta_pan_tx_flow,
        bta_pan_write_buf, bta_pan_conn_open, bta_pan_conn_close, bta_pan_free_buf,
};

/* state table information */
#define BTA_PAN_ACTIONS 1    /* number of actions */
#define BTA_PAN_NEXT_STATE 1 /* position of next state */
#define BTA_PAN_NUM_COLS 2   /* number of columns in state tables */

/* state table for listen state */
const uint8_t bta_pan_st_idle[][BTA_PAN_NUM_COLS] = {
        /* API_CLOSE */ {BTA_PAN_API_CLOSE, BTA_PAN_IDLE_ST},
        /* CI_TX_READY */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* CI_RX_READY */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* CI_TX_FLOW */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* CI_RX_WRITE */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* CI_RX_WRITEBUF */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* PAN_CONN_OPEN */ {BTA_PAN_CONN_OPEN, BTA_PAN_OPEN_ST},
        /* PAN_CONN_CLOSE */ {BTA_PAN_CONN_OPEN, BTA_PAN_IDLE_ST},
        /* FLOW_ENABLE */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
        /* BNEP_DATA */ {BTA_PAN_IGNORE, BTA_PAN_IDLE_ST},
};

/* state table for open state */
const uint8_t bta_pan_st_open[][BTA_PAN_NUM_COLS] = {
        /* API_CLOSE */ {BTA_PAN_API_CLOSE, BTA_PAN_OPEN_ST},
        /* CI_TX_READY */ {BTA_PAN_TX_PATH, BTA_PAN_OPEN_ST},
        /* CI_RX_READY */ {BTA_PAN_RX_PATH, BTA_PAN_OPEN_ST},
        /* CI_TX_FLOW */ {BTA_PAN_TX_FLOW, BTA_PAN_OPEN_ST},
        /* CI_RX_WRITE */ {BTA_PAN_IGNORE, BTA_PAN_OPEN_ST},
        /* CI_RX_WRITEBUF */ {BTA_PAN_WRITE_BUF, BTA_PAN_OPEN_ST},
        /* PAN_CONN_OPEN */ {BTA_PAN_IGNORE, BTA_PAN_OPEN_ST},
        /* PAN_CONN_CLOSE */ {BTA_PAN_CONN_CLOSE, BTA_PAN_IDLE_ST},
        /* FLOW_ENABLE */ {BTA_PAN_RX_PATH, BTA_PAN_OPEN_ST},
        /* BNEP_DATA */ {BTA_PAN_TX_PATH, BTA_PAN_OPEN_ST},
};

/* state table for closing state */
const uint8_t bta_pan_st_closing[][BTA_PAN_NUM_COLS] = {
        /* API_CLOSE */ {BTA_PAN_IGNORE, BTA_PAN_CLOSING_ST},
        /* CI_TX_READY */ {BTA_PAN_TX_PATH, BTA_PAN_CLOSING_ST},
        /* CI_RX_READY */ {BTA_PAN_RX_PATH, BTA_PAN_CLOSING_ST},
        /* CI_TX_FLOW */ {BTA_PAN_TX_FLOW, BTA_PAN_CLOSING_ST},
        /* CI_RX_WRITE */ {BTA_PAN_IGNORE, BTA_PAN_CLOSING_ST},
        /* CI_RX_WRITEBUF */ {BTA_PAN_FREE_BUF, BTA_PAN_CLOSING_ST},
        /* PAN_CONN_OPEN */ {BTA_PAN_IGNORE, BTA_PAN_CLOSING_ST},
        /* PAN_CONN_CLOSE */ {BTA_PAN_CONN_CLOSE, BTA_PAN_IDLE_ST},
        /* FLOW_ENABLE */ {BTA_PAN_RX_PATH, BTA_PAN_CLOSING_ST},
        /* BNEP_DATA */ {BTA_PAN_TX_PATH, BTA_PAN_CLOSING_ST},
};

/* type for state table */
typedef const uint8_t (*tBTA_PAN_ST_TBL)[BTA_PAN_NUM_COLS];

/* state table */
const tBTA_PAN_ST_TBL bta_pan_st_tbl[] = {bta_pan_st_idle, bta_pan_st_open, bta_pan_st_closing};

/*****************************************************************************
 * Global data
 ****************************************************************************/

/* PAN control block */
tBTA_PAN_CB bta_pan_cb;

/*******************************************************************************
 *
 * Function         bta_pan_scb_alloc
 *
 * Description      Allocate a PAN server control block.
 *
 *
 * Returns          pointer to the scb, or NULL if none could be allocated.
 *
 ******************************************************************************/
tBTA_PAN_SCB* bta_pan_scb_alloc(void) {
  tBTA_PAN_SCB* p_scb = &bta_pan_cb.scb[0];
  int i;

  for (i = 0; i < BTA_PAN_NUM_CONN; i++, p_scb++) {
    if (!p_scb->in_use) {
      p_scb->in_use = true;
      log::verbose("bta_pan_scb_alloc {}", i);
      break;
    }
  }

  if (i == BTA_PAN_NUM_CONN) {
    /* out of scbs */
    p_scb = NULL;
    log::warn("Out of scbs");
  }
  return p_scb;
}

/*******************************************************************************
 *
 * Function         bta_pan_sm_execute
 *
 * Description      State machine event handling function for PAN
 *
 *
 * Returns          void
 *
 ******************************************************************************/
static void bta_pan_sm_execute(tBTA_PAN_SCB* p_scb, uint16_t event, tBTA_PAN_DATA* p_data) {
  tBTA_PAN_ST_TBL state_table;
  uint8_t action;
  int i;

  log::verbose("PAN scb={} event=0x{:x} state={}", bta_pan_scb_to_idx(p_scb), event, p_scb->state);

  /* look up the state table for the current state */
  state_table = bta_pan_st_tbl[p_scb->state];

  event &= 0x00FF;

  /* set next state */
  p_scb->state = state_table[event][BTA_PAN_NEXT_STATE];

  /* execute action functions */
  for (i = 0; i < BTA_PAN_ACTIONS; i++) {
    action = state_table[event][i];
    log::assert_that(action < BTA_PAN_MAX_ACTIONS, "assert failed: action < BTA_PAN_MAX_ACTIONS");
    if (action == BTA_PAN_IGNORE) {
      continue;
    }
    (*bta_pan_action[action])(p_scb, p_data);
  }
}

/*******************************************************************************
 *
 * Function         bta_pan_api_enable
 *
 * Description      Handle an API enable event.
 *
 *
 * Returns          void
 *
 ******************************************************************************/
static void bta_pan_api_enable(tBTA_PAN_DATA* p_data) {
  /* initialize control block */
  memset(&bta_pan_cb, 0, sizeof(bta_pan_cb));

  /* store callback function */
  bta_pan_cb.p_cback = p_data->api_enable.p_cback;
  bta_pan_enable(p_data);
}

/*******************************************************************************
 *
 * Function         bta_pan_api_disable
 *
 * Description      Handle an API disable event.
 *
 *
 * Returns          void
 *
 ******************************************************************************/
static void bta_pan_api_disable(tBTA_PAN_DATA* /* p_data */) { bta_pan_disable(); }

/*******************************************************************************
 *
 * Function         bta_pan_api_open
 *
 * Description      Handle an API listen event.
 *
 *
 * Returns          void
 *
 ******************************************************************************/
static void bta_pan_api_open(tBTA_PAN_DATA* p_data) {
  tBTA_PAN_SCB* p_scb;
  tBTA_PAN bta_pan;

  /* allocate an scb */
  p_scb = bta_pan_scb_alloc();
  if (p_scb != NULL) {
    bta_pan_open(p_scb, p_data);
  } else {
    bta_pan.open.bd_addr = p_data->api_open.bd_addr;
    bta_pan.open.status = BTA_PAN_FAIL;
    bta_pan_cb.p_cback(BTA_PAN_OPEN_EVT, &bta_pan);
  }
}
/*******************************************************************************
 *
 * Function         bta_pan_scb_dealloc
 *
 * Description      Deallocate a link control block.
 *
 *
 * Returns          void
 *
 ******************************************************************************/
void bta_pan_scb_dealloc(tBTA_PAN_SCB* p_scb) {
  log::verbose("bta_pan_scb_dealloc {}", bta_pan_scb_to_idx(p_scb));
  fixed_queue_free(p_scb->data_queue, NULL);
  memset(p_scb, 0, sizeof(tBTA_PAN_SCB));
}

/*******************************************************************************
 *
 * Function         bta_pan_scb_to_idx
 *
 * Description      Given a pointer to an scb, return its index.
 *
 *
 * Returns          Index of scb.
 *
 ******************************************************************************/
uint8_t bta_pan_scb_to_idx(tBTA_PAN_SCB* p_scb) { return ((uint8_t)(p_scb - bta_pan_cb.scb)) + 1; }

/*******************************************************************************
 *
 * Function         bta_pan_scb_by_handle
 *
 * Description      Find scb associated with handle.
 *
 *
 * Returns          Pointer to scb or NULL if not found.
 *
 ******************************************************************************/
tBTA_PAN_SCB* bta_pan_scb_by_handle(uint16_t handle) {
  tBTA_PAN_SCB* p_scb = &bta_pan_cb.scb[0];
  uint8_t i;

  for (i = 0; i < BTA_PAN_NUM_CONN; i++, p_scb++) {
    if (p_scb->handle == handle) {
      return p_scb;
      ;
    }
  }

  log::warn("No scb for handle {}", handle);

  return NULL;
}

/*******************************************************************************
 *
 * Function         bta_pan_hdl_event
 *
 * Description      Data gateway main event handling function.
 *
 *
 * Returns          void
 *
 ******************************************************************************/
bool bta_pan_hdl_event(const BT_HDR_RIGID* p_msg) {
  tBTA_PAN_SCB* p_scb;
  bool freebuf = true;

  switch (p_msg->event) {
    /* handle enable event */
    case BTA_PAN_API_ENABLE_EVT:
      bta_pan_api_enable((tBTA_PAN_DATA*)p_msg);
      break;

    /* handle disable event */
    case BTA_PAN_API_DISABLE_EVT:
      bta_pan_api_disable((tBTA_PAN_DATA*)p_msg);
      break;

    /* handle set role event */
    case BTA_PAN_API_SET_ROLE_EVT:
      bta_pan_set_role((tBTA_PAN_DATA*)p_msg);
      break;

    /* handle open event */
    case BTA_PAN_API_OPEN_EVT:
      bta_pan_api_open((tBTA_PAN_DATA*)p_msg);
      break;

    /* events that require buffer not be released */
    case BTA_PAN_CI_RX_WRITEBUF_EVT:
      freebuf = false;
      p_scb = bta_pan_scb_by_handle(p_msg->layer_specific);
      if (p_scb != NULL) {
        bta_pan_sm_execute(p_scb, p_msg->event, (tBTA_PAN_DATA*)p_msg);
      }
      break;

    /* all other events */
    default:
      p_scb = bta_pan_scb_by_handle(p_msg->layer_specific);
      if (p_scb != NULL) {
        bta_pan_sm_execute(p_scb, p_msg->event, (tBTA_PAN_DATA*)p_msg);
      }
      break;
  }
  return freebuf;
}