#include <ranges>
#include <bcm2835.h>

#include "util.hpp"

/* ADDRESS SETUP TIME
 * depends on clock frequency, see datasheet.  max 150@2MHz
 * address is set after setup time (tADS) and is being hold for address hold time (tAH)
 * 
 * 
 */
constexpr uint64_t addressSetupTimeUS = 1;  // 300e-9 s

class EEPROM {
    EEPROM(const IOPins& ioPins, const AddressPins& addressPins, const Pin& pinCEb, const Pin& pinWEb, const Pin& pinOEb) {
        
    }
}

void initPins() {
    // set to input and pullup
    auto setPinsInput = []<std::ranges::forward_range T>(const T& t) {
        for (auto it = t.begin(); it != t.end(); it++) {
            bcm2835_gpio_fsel(*it, BCM2835_GPIO_FSEL_INPT);
            /* bcm2835_gpio_set_pud(*it,  BCM2835_GPIO_PUD_UP); */
            bcm2835_gpio_set_pud(*it,  BCM2835_GPIO_PUD_OFF);
        }
    };
    setPinsInput(addressPins);
    setPinsInput(dataPins);
    setPinsInput(controlPins);
}


void setIODirection(uint8_t direction) {
    for (int i = 0; i < dataPins.size(); i++) {
        bcm2835_gpio_fsel(dataPins.at(i), direction);
    }
}


bool isChipEnabled() {
    return !bcm2835_gpio_lev(CEb);
}

inline bool isRead() {
    return bcm2835_gpio_lev(RWb);
}


uint16_t readAddress() {
    uint16_t address = 0;
    for (int i = 0; i < addressPins.size(); i++) {
        address |= (bcm2835_gpio_lev(addressPins.at(i)) << i);
    }
    return address;
}

uint8_t readData() {
    uint8_t address = 0;
    for (int i = 0; i < dataPins.size(); i++) {
        address |= (bcm2835_gpio_lev(dataPins.at(i)) << i);
    }
    return address;
}

inline void waitForFallingEdge(uint8_t pin) {
    while (bcm2835_gpio_lev(pin) == LOW);
    while (bcm2835_gpio_lev(pin) == HIGH);
}
inline void waitForRisingEdge(uint8_t pin) {
    while (bcm2835_gpio_lev(pin) == HIGH);
    while (bcm2835_gpio_lev(pin) == LOW);
}
inline void waitForEdge(uint8_t pin) {
    if (bcm2835_gpio_lev(pin) == HIGH) {
        while (bcm2835_gpio_lev(pin) == HIGH);
        return;
    }
    else {
        while (bcm2835_gpio_lev(pin) == LOW);
        return;
    }
}

/**
 * @brief Simulate an AT28C256 EEPROM
 * @details
 *  While the CEb is low, constantly read the address and put the corresponding data on the bus.
 *  While CEb is high, set data pins to input.
 */
void simulateEEPROM(std::stop_token token, std::array<char, UINT16_MAX> data) {
    initPins();
    printf("Begin EEPROM simulation\n");

    uint16_t lastAddress = 0;
    bool outputActive = false;

    while (!token.stop_requested()) {
        uint16_t currentAddress = readAddress();
        bool chipEnabled = isChipEnabled();
        if (chipEnabled && (!outputActive || (currentAddress != lastAddress))) {
            setIODirection(BCM2835_GPIO_FSEL_OUTP);
            outputActive = true;

            uint32_t valueMask = byteToMask(data.at(currentAddress), dataPins);
            bcm2835_gpio_write_mask(valueMask, ioMask);
            /* std::cout << ">-" << gz::toBinString(currentAddress) << "[" << gz::toHexString(currentAddress) << "]-" << gz::toBinString(data.at(currentAddress)) << "[" << gz::toHexString(static_cast<uint16_t>(data.at(currentAddress)), 2) << "]"; */
            /* std::cout << std::endl; */
        }

        if (!chipEnabled && outputActive) {
            setIODirection(BCM2835_GPIO_FSEL_INPT);
            outputActive = false;
        }

        lastAddress = currentAddress;
    }
    printf("End EEPROM simulation\n");
}