//---------------------------------------------------------------------------
//
//	SCSI Target Emulator PiSCSI
//	for Raspberry Pi
//
//  Copyright (C) 2022 akuker
//
//	[ Hardware version detection routines ]
//
//---------------------------------------------------------------------------

#include "sbc_version.h"
#include <spdlog/spdlog.h>
#include <fstream>
#include <iostream>
#include <sstream>

SBC_Version::sbc_version_type SBC_Version::sbc_version = sbc_version_type::sbc_unknown;

// TODO: THESE NEED TO BE VALIDATED!!!!
const string SBC_Version::str_raspberry_pi_1    = "Raspberry Pi 1";
const string SBC_Version::str_raspberry_pi_2_3  = "Raspberry Pi 2/3";
const string SBC_Version::str_raspberry_pi_4    = "Raspberry Pi 4";
const string SBC_Version::str_unknown_sbc       = "Unknown SBC";

// The strings in this table should align with the 'model' embedded
// in the device tree. This can be aquired by running:
//     cat /proc/device-tree/model
// Only the first part of the string is checked. Anything following
// will be ignored. For example:
//     "Raspberry Pi 4 Model B" will match with both of the following:
//         - Raspberry Pi 4 Model B Rev 1.4
//         - Raspberry Pi 4 Model B Rev 1.3
// TODO Is there a better way to detect the Pi type than relying on strings?
const map<string, SBC_Version::sbc_version_type, less<>> SBC_Version::proc_device_tree_mapping = {
    {"Raspberry Pi 1 Model ", sbc_version_type::sbc_raspberry_pi_1},
    {"Raspberry Pi 2 Model ", sbc_version_type::sbc_raspberry_pi_2_3},
    {"Raspberry Pi 3 Model ", sbc_version_type::sbc_raspberry_pi_2_3},
    {"Raspberry Pi 4 Model ", sbc_version_type::sbc_raspberry_pi_4},
    {"Raspberry Pi 400 ", sbc_version_type::sbc_raspberry_pi_4},
    {"Raspberry Pi Zero W", sbc_version_type::sbc_raspberry_pi_1},
    {"Raspberry Pi Zero", sbc_version_type::sbc_raspberry_pi_1}
};

const string SBC_Version::m_device_tree_model_path = "/proc/device-tree/model";

//---------------------------------------------------------------------------
//
//	Convert the SBC Version to a printable string
//
//---------------------------------------------------------------------------
string SBC_Version::GetAsString()
{
    switch (sbc_version) {
    case sbc_version_type::sbc_raspberry_pi_1:
        return str_raspberry_pi_1;
    case sbc_version_type::sbc_raspberry_pi_2_3:
        return str_raspberry_pi_2_3;
    case sbc_version_type::sbc_raspberry_pi_4:
        return str_raspberry_pi_4;
    default:
        return str_unknown_sbc;
    }
}

SBC_Version::sbc_version_type SBC_Version::GetSbcVersion()
{
    return sbc_version;
}

//---------------------------------------------------------------------------
//
//	Determine which version of single board computer (Pi) is being used
//  based upon the device tree model string.
//
//---------------------------------------------------------------------------
void SBC_Version::Init()
{
    ifstream input_stream(SBC_Version::m_device_tree_model_path);

    if (input_stream.fail()) {
#if defined(__x86_64__) || defined(__X86__)
        // We expect this to fail on x86
    	spdlog::warn("Detected " + GetAsString());
        sbc_version = sbc_version_type::sbc_unknown;
        return;
#else
        spdlog::error("Failed to open " + SBC_Version::m_device_tree_model_path + ". Are you running as root?");
        throw invalid_argument("Failed to open /proc/device-tree/model");
#endif
    }

    stringstream str_buffer;
    str_buffer << input_stream.rdbuf();
    const string device_tree_model = str_buffer.str();

    for (const auto& [key, value] : proc_device_tree_mapping) {
    	if (device_tree_model.starts_with(key)) {
    		sbc_version = value;
    		spdlog::info("Detected " + GetAsString());
    		return;
    	}
    }

    sbc_version = sbc_version_type::sbc_raspberry_pi_4;
    spdlog::error("Unable to determine single board computer type. Defaulting to Raspberry Pi 4");
}

bool SBC_Version::IsRaspberryPi()
{
    switch (sbc_version) {
    case sbc_version_type::sbc_raspberry_pi_1:
    case sbc_version_type::sbc_raspberry_pi_2_3:
    case sbc_version_type::sbc_raspberry_pi_4:
        return true;
    default:
        return false;
    }
}

// The following functions are only used on the Raspberry Pi
//	(imported from bcm_host.c)
uint32_t SBC_Version::GetDeviceTreeRanges(const char *filename, uint32_t offset)
{
    uint32_t address = ~0;
    if (FILE *fp = fopen(filename, "rb"); fp) {
        fseek(fp, offset, SEEK_SET);
        if (array<uint8_t, 4> buf; fread(buf.data(), 1, buf.size(), fp) == buf.size()) {
            address = (int)buf[0] << 24 | (int)buf[1] << 16 | (int)buf[2] << 8 | (int)buf[3] << 0;
        }
        fclose(fp);
    }
    return address;
}

#if defined __linux__
uint32_t SBC_Version::GetPeripheralAddress(void)
{
    uint32_t address = GetDeviceTreeRanges("/proc/device-tree/soc/ranges", 4);
    if (address == 0) {
        address = GetDeviceTreeRanges("/proc/device-tree/soc/ranges", 8);
    }
    address = (address == (uint32_t)~0) ? 0x20000000 : address;

    return address;
}
#elif defined __NetBSD__
uint32_t SBC_Version::GetPeripheralAddress(void)
{
    char buf[1024];
    size_t len = sizeof(buf);
    uint32_t address;

    if (sysctlbyname("hw.model", buf, &len, NULL, 0) || strstr(buf, "ARM1176JZ-S") != buf) {
        // Failed to get CPU model || Not BCM2835
        // use the address of BCM283[67]
        address = 0x3f000000;
    } else {
        // Use BCM2835 address
        address = 0x20000000;
    }
    return address;
}
#else
uint32_t SBC_Version::GetPeripheralAddress(void)
{
    return 0;
}
#endif