#include <stdint.h>
#include <stddef.h>

#include <drivers/pci.h>
#include <port_io.h>
#include <stdio.h>

#define PCI_CONFIG_ADDRESS 0xCF8
#define PCI_CONFIG_DATA 0xCFC

uint32_t pci_config_read(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset)
{
    uint32_t address = 0;
    address |= (bus << 16);         // Bus number (bits 23-16)
    address |= (device << 11);      // Device number (bits 15-11)
    address |= (function << 8);     // Function number (bits 10-8)
    address |= (offset & 0xFC);    // Register offset (bits 7-0)
    address |= (1 << 31);           // Enable configuration access

    outl(PCI_CONFIG_ADDRESS, address);  // Write address to PCI config space
    return inl(PCI_CONFIG_DATA);        // Read data from PCI config space
}

void pci_config_write(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint32_t value)
{
    uint32_t address = 0x80000000 | (bus << 16) | (device << 11) | (function << 8) | (offset & 0xFC);
    outl(PCI_CONFIG_ADDRESS, address); // Send the address to PCI config space
    outl(PCI_CONFIG_DATA, value); // Write data to PCI config space
}

void pci_enumerate()
{
    for (uint16_t bus = 0; bus < 256; bus++) // Maximum 256 buses
    {
        for (uint8_t device = 0; device < 32; device++) // Maximum 32 devices per bus
        {
            for (uint8_t function = 0; function < 8; function++) // Maximum 8 functions per device
            {
                uint32_t vendor_id = pci_config_read(bus, device, function, 0x00);
                if (vendor_id == 0xFFFFFFFF) continue; // No device present

                uint32_t device_id = pci_config_read(bus, device, function, 0x02);
                uint32_t class_code = pci_config_read(bus, device, function, 0x08);
                printf("Found PCI device: Vendor ID: 0x%X Device ID: 0x%X Class: 0x%X\n", vendor_id, device_id, class_code);
                
                printf("0x%X", class_code);
                printf(" --- ");
                printf("0x%X\n", (class_code >> 8));
                
                
                if ((class_code >> 8) == 0x0C) {
                    printf("Found USB controller (Class: 0x%02X)\n", class_code);
                    // Now, you can initialize and configure the USB controller.
                }

            }
        }
    }
}