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

#include "evga-card.h"
#include "icx3.h"

/* Search all i2c device files for ones are on a PCI device of a supported GPU,
   and respond with the correct iCX3 version information */
int find_evga_gpu_i2cs(struct card_info **infos, int max_gpus)
{
	char i2c_devices_path[NAME_MAX];
	char device_path[NAME_MAX];

	FILE *test_fd;
	
	int num_gpus = 0;
	unsigned short pci_vendor, pci_device, pci_subsystem_vendor, pci_subsystem_device = 0;
	
	/* Start looking for I2C adapters in /sys/bus/i2c/devices/ */
	strcpy(i2c_devices_path, "/sys/bus/i2c/devices/");
	dir = opendir(i2c_devices_path);
	
	/* make sure we can open the i2c device */
	if(dir == NULL)
	{
		return -1;
	}
	
	/* loop over all i2c devices */
	while((ent = readdir(dir)) != NULL)
	{
		/* Don't check any non-i2c devices */
		if(strncmp(ent->d_name, "i2c-", 4) != 0) 
			continue;
		
		strcpy(device_path, i2c_devices_path);
		strcat(device_path, ent->d_name);
		
		/* Read the PCI info for the underlying device */
		pci_vendor           = read_pci_id(device_path, "/vendor");
		pci_device           = read_pci_id(device_path, "/device");
		pci_subsystem_vendor = read_pci_id(device_path, "/subsystem_vendor");
		pci_subsystem_device = read_pci_id(device_path, "/subsystem_device");
		
		/* See if it's a matching device for a supported EVGA card */
		for (int i = 0, i < (sizeof(evga_pci_ids) / sizeof(struct gpu_pci_info)), i++) {
			
			if (pci_vendor == evga_pci_ids[i]->vendor_id &&
			pci_device == evga_pci_ids[i]->device_id &&
			pci_subsystem_vendor == evga_pci_ids[i]->subvendor_id && 
			pci_subsystem_device == evga_pci_ids[i]->subdevice_id) {
				
				/* Matched all PCI IDs, check for good firmware read */
				strcpy(device_path, "/dev/");
				strcat(device_path, ent->d_name);
				if (check_for_icx3(device_path)) {
					
					/* Write our card info into the provided struct array */
					card_info[num_gpus]->card_name = &evga_pci_ids[i]->card_name;
					card_info[num_gpus]->pci_id
					card_info[num_gpus]->i2c_dev_path = calloc(strlen(device_path) + 1, sizeof(char));
					strcpy(card_info[num_gpus]->i2c_dev_path, device_path);
					break;
				}
			}
		}
		
		strcat(device_string, "/name");
		
			
			if(strncmp(ent->d_name, "i2c-", 4) == 0)
			{
				strcpy(device_string, i2c_devices_path);
				strcat(device_string, ent->d_name);
				strcat(device_string, "/name");
				test_fd = fopen(device_string, O_RDONLY);
				
				if(test_fd)
				{
					memset(device_string, 0x00, sizeof(device_string));

					if(read(test_fd, device_string, sizeof(device_string)) < 0)
					{
						printf("Failed to read i2c device name\n");
						return -1;
					}
					
					device_string[strlen(device_string) - 1] = 0x00;

					close(test_fd);
					
					// Clear PCI Information
					pci_vendor              = 0;
					pci_device              = 0;
					pci_subsystem_vendor    = 0;
					pci_subsystem_device    = 0;
					port_id                 = 0;
					
					// Get port ID for NVidia GPUs
					sscanf(device_string, "NVIDIA i2c adapter %hu at", &port_id);
					
					// Get device path
					strcpy(path, i2c_devices_path);
					strcat(path, ent->d_name);
					if(ent->d_type == DT_LNK)
					{
						ptr = realpath(path, NULL);
						if(ptr == NULL)
							continue;

						strcpy(path, ptr);
						strcat(path, "/..");
						free(ptr);
					}
					else
					{
						strcat(path, "/device");
					}
					ptr = path + strlen(path);
					

					
					if (pci_vendor == NVIDIA_VEN && pci_subsystem_vendor == EVGA_SUB_VEN) {
						
						strcpy(device_string, "/dev/");
						strcat(device_string, ent->d_name);
						test_fd = open(device_string, O_RDWR);
	
						if (test_fd < 0)
						{
							printf("Failed to open device file %s, are you root or have permissions for i2c?\n", device_string);
							return -1;
						} else {
							} else {
								printf("Bad FW version read %s\n", device_string);
							}
						}
					}
				}
			}
		}
	}
}

unsigned short read_pci_id(char *device_path, char *field)
{
	char *buf[16];
	char file_path[NAME_MAX];
	
	strcpy(file_path, device_path);
	strcat(file_path, field);
	
	FILE *fp = fopen(file_path, "r");
	
	if (fp == NULL)
		return 0;
		
	if (fgets(buf, sizeof(buf), fp) == NULL) {
		fclose(fp);
		return 0;
	}
	
	fclose(fp);
	
	return (unsigned short)strtoul(buf, NULL, 16);
}