#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdbool.h>
#include <errno.h>
#include <sys/auxv.h>
#include <asm/hwcap.h>

#include "../common/global.h"
#include "udev.h"
#include "midr.h"
#include "uarch.h"
#include "soc.h"

struct cache* get_cache_info(struct cpuInfo* cpu) {
  struct cache* cach = emalloc(sizeof(struct cache));
  init_cache_struct(cach);

  cach->max_cache_level = 2;
  for(int i=0; i < cach->max_cache_level + 1; i++) {
    cach->cach_arr[i]->exists = true;
    cach->cach_arr[i]->num_caches = 1;
    cach->cach_arr[i]->size = 0;
  }

  return cach;
}

struct frequency* get_frequency_info(uint32_t core) {
  struct frequency* freq = emalloc(sizeof(struct frequency));

  freq->base = UNKNOWN_FREQ;
  freq->max = get_max_freq_from_file(core, false);

  return freq;
}

struct topology* get_topology_info(struct cpuInfo* cpu, struct cache* cach, uint32_t* midr_array, int socket_idx, int ncores) {
  struct topology* topo = emalloc(sizeof(struct topology));
  init_topology_struct(topo, cach);

  int sockets_seen = 0;
  int first_core_idx = 0;
  int currrent_core_idx = 0;
  int cores_in_socket = 0;

  while(socket_idx + 1 > sockets_seen) {
    if(midr_array[first_core_idx] == midr_array[currrent_core_idx] && currrent_core_idx < ncores) {
      currrent_core_idx++;
      cores_in_socket++;
    }
    else {
      topo->total_cores = cores_in_socket;
      cores_in_socket = 0;
      first_core_idx = currrent_core_idx;
      sockets_seen++;
    }
  }

  return topo;
}

bool cores_are_equal(int c1pos, int c2pos, uint32_t* midr_array, int32_t* freq_array) {
  return midr_array[c1pos] == midr_array[c2pos] && freq_array[c1pos] == freq_array[c2pos];
}

uint32_t fill_ids_from_midr(uint32_t* midr_array, int32_t* freq_array, uint32_t* ids_array, int len) {
  uint32_t latest_id = 0;
  bool found;
  ids_array[0] = latest_id;

  for (int i = 1; i < len; i++) {
    int j = 0;
    found = false;

    for (j = 0; j < len && !found; j++) {
      if (i != j && cores_are_equal(i, j, midr_array, freq_array)) {
        if(j > i) {
          latest_id++;
          ids_array[i] = latest_id;
        }
        else {
          ids_array[i] = ids_array[j];
        }
        found = true;
      }
    }
    if(!found) {
      latest_id++;
      ids_array[i] = latest_id;
    }
  }

  return latest_id+1;
}

void init_cpu_info(struct cpuInfo* cpu) {
  cpu->next_cpu = NULL;
}

// We assume all cpus share the same hardware
// capabilities but I'm not sure it is always
// true...
// ARM32 https://elixir.bootlin.com/linux/latest/source/arch/arm/include/uapi/asm/hwcap.h
// ARM64 https://elixir.bootlin.com/linux/latest/source/arch/arm64/include/uapi/asm/hwcap.h
struct features* get_features_info() {
  struct features* feat = emalloc(sizeof(struct features));
  bool *ptr = &(feat->AES);
  for(uint32_t i = 0; i < sizeof(struct features)/sizeof(bool); i++, ptr++) {
    *ptr = false;
  }

  errno = 0;
  long hwcaps = getauxval(AT_HWCAP);

  if(errno == ENOENT) {
    printWarn("Unable to retrieve AT_HWCAP using getauxval");
  }
#ifdef __aarch64__
  else {
    feat->AES = hwcaps & HWCAP_AES;
    feat->CRC32 = hwcaps & HWCAP_CRC32;
    feat->SHA1 = hwcaps & HWCAP_SHA1;
    feat->SHA2 = hwcaps & HWCAP_SHA2;
    feat->NEON = hwcaps & HWCAP_ASIMD;
  }
#else
  else {
    feat->NEON = hwcaps & HWCAP_NEON;
  }

  hwcaps = getauxval(AT_HWCAP2);
  if(errno == ENOENT) {
    printWarn("Unable to retrieve AT_HWCAP2 using getauxval");
  }
  else {
    feat->AES = hwcaps & HWCAP2_AES;
    feat->CRC32 = hwcaps & HWCAP2_CRC32;
    feat->SHA1 = hwcaps & HWCAP2_SHA1;
    feat->SHA2 = hwcaps & HWCAP2_SHA2;
  }
#endif

  return feat;
}

struct cpuInfo* get_cpu_info() {
  struct cpuInfo* cpu = emalloc(sizeof(struct cpuInfo));
  init_cpu_info(cpu);

  int ncores = get_ncores_from_cpuinfo();
  bool success = false;
  int32_t* freq_array = emalloc(sizeof(uint32_t) * ncores);
  uint32_t* midr_array = emalloc(sizeof(uint32_t) * ncores);
  uint32_t* ids_array = emalloc(sizeof(uint32_t) * ncores);

  for(int i=0; i < ncores; i++) {
    midr_array[i] = get_midr_from_cpuinfo(i, &success);

    if(!success) {
      printWarn("Unable to fetch MIDR for core %d. This is probably because the core is offline", i);
      midr_array[i] = midr_array[0];
    }

    freq_array[i] = get_max_freq_from_file(i, false);
    if(freq_array[i] == UNKNOWN_FREQ) {
      printWarn("Unable to fetch max frequency for core %d. This is probably because the core is offline", i);
      freq_array[i] = freq_array[0];
    }
  }
  uint32_t sockets = fill_ids_from_midr(midr_array, freq_array, ids_array, ncores);

  struct cpuInfo* ptr = cpu;
  int midr_idx = 0;
  int tmp_midr_idx = 0;
  for(uint32_t i=0; i < sockets; i++) {
    if(i > 0) {
      ptr->next_cpu = emalloc(sizeof(struct cpuInfo));
      ptr = ptr->next_cpu;
      init_cpu_info(ptr);

      tmp_midr_idx = midr_idx;
      while(cores_are_equal(midr_idx, tmp_midr_idx, midr_array, freq_array)) tmp_midr_idx++;
      midr_idx = tmp_midr_idx;
    }

    ptr->midr = midr_array[midr_idx];
    ptr->arch = get_uarch_from_midr(ptr->midr, ptr);

    ptr->feat = get_features_info();
    ptr->freq = get_frequency_info(midr_idx);
    ptr->cach = get_cache_info(ptr);
    ptr->topo = get_topology_info(ptr, ptr->cach, midr_array, i, ncores);
  }

  cpu->num_cpus = sockets;
  cpu->hv = emalloc(sizeof(struct hypervisor));
  cpu->hv->present = false;
  cpu->soc = get_soc();

  return cpu;
}

char* get_str_topology(struct cpuInfo* cpu, struct topology* topo, bool dual_socket) {
  uint32_t size = 3+7+1;
  char*  string = emalloc(sizeof(char)*size);
  snprintf(string, size, "%d cores", topo->total_cores);

  return string;
}

bool get_peak_performance(struct cpuInfo* cpu, double* flops) {
  struct cpuInfo* ptr = cpu;

  //First check we have consistent data
  for(int i=0; i < cpu->num_cpus; ptr = ptr->next_cpu, i++) {
    if(get_freq(ptr->freq) == UNKNOWN_FREQ) {
      return false;
    }
  }

  *flops = 0.0;

  ptr = cpu;
  for(int i=0; i < cpu->num_cpus; ptr = ptr->next_cpu, i++) {
    *flops += ptr->topo->total_cores * (get_freq(ptr->freq) * 1000000);
  }
  if(cpu->feat->NEON) *flops = *flops * 4;

  return true;
}

char* get_str_features(struct cpuInfo* cpu) {
  struct features* feat = cpu->feat;
  char* string = emalloc(sizeof(char) * 25);
  uint32_t len = 0;

  if(feat->NEON) {
    strcat(string, "NEON,");
    len += 5;
  }
  if(feat->SHA1) {
    strcat(string, "SHA1,");
    len += 5;
  }
  if(feat->SHA2) {
    strcat(string, "SHA2,");
    len += 5;
  }
  if(feat->AES) {
    strcat(string, "AES,");
    len += 4;
  }
  if(feat->CRC32) {
    strcat(string, "CRC32,");
    len += 6;
  }

  if(len > 0) {
    string[len-1] = '\0';
    return string;
  }
  else
    return NULL;
}

void print_debug(struct cpuInfo* cpu) {
  int ncores = get_ncores_from_cpuinfo();
  bool success = false;

  for(int i=0; i < ncores; i++) {
    printf("[Core %d] ", i);
    long freq = get_max_freq_from_file(i, false);
    uint32_t midr = get_midr_from_cpuinfo(i, &success);
    if(!success) {
      printWarn("Unable to fetch MIDR for core %d. This is probably because the core is offline", i);
      printf("0x%.8X ", get_midr_from_cpuinfo(0, &success));
    }
    else {
      printf("0x%.8X ", midr);
    }
    if(freq == UNKNOWN_FREQ) {
      printWarn("Unable to fetch max frequency for core %d. This is probably because the core is offline", i);
      printf("%ld MHz\n", get_max_freq_from_file(0, false));
    }
    else {
      printf("%ld MHz\n", freq);
    }
  }
}

void free_topo_struct(struct topology* topo) {
  free(topo);
}