/*
Main Source File
*/
#include "i2c_target.h"
#include "ti/devices/msp/peripherals/hw_dac12.h"
#include "ti/driverlib/dl_adc12.h"
#include "ti/driverlib/dl_gpio.h"
#include "ti/driverlib/dl_i2c.h"
#include "ti/driverlib/m0p/dl_core.h"
#include "ti_msp_dl_config.h"
#include "ti/comm_modules/i2c/controller/i2c_comm_controller.h"
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "multiplexer.h"
#include "adc.h"
#include "dac.h"
#include "battery.h"
#include "i2c_target.h"
#include "cc_cv_charging.h"
#include <ti/drivers/GPIO.h>


I2C_Instance gI2C;
I2C_ResponseInfo gResponse;
BatteryData battery_data;


/*Interrupt for MCU -> ADC
* CASE: DL_I2C_IIDX_CONTROLLER_RX_DONE: ADC Reception Complete
    - ADC has finished sending data and it's fully received.
    - gI2C.rxMsg.len = gI2C.rxMsg.ptr:
        - Stores the received data length in the response buffer.
    - I2C_decodeResponse():
        - Decodes the received response.
    - gI2C.status = I2C_STATUS_RX_COMPLETE:
        - Marks reception is complete.
* CASE: DL_I2C_IIDX_CONTROLLER_TX_DONE: Data Transmit to ADC complete
    - DL_I2C_disableInterrupt(..): Disables the TXFIFO interrupt since data is now sent
* CASE: DL_I2C_IIDX_CONTROLLER_RXFIFO_TRIGGER: Receive Data in FIFO
    - The I2C Receive FIFO has data ready to be read.
    - while (DL_I2C_isControllerRXFIFOEmpty(...) != true): Loops until the RX FIFOis empty (READ all available bytes)
    - Inside the while loop:
        - If buffer has SPACE, store the received byte
        - Prints each received byte in HEXADECIMAL format for debugging
        - IF BUFFER is FULL, avoids OVERFLOW by discarding extra byte.
* CASE: DL_I2C_IIDX_CONTROLLER_TXFIFO_TRIGGER: Transmit Data in FIFO
        - If there is still data to send:
        gI2C.txMsg.ptr += DL_I2C_fillControllerTXFIFO(I2C_controller_INST, &gI2C.txMsg.buffer[gI2C.txMsg.ptr], gI2C.txMsg.len - gI2C.txMsg.ptr);

*/
void I2C_controller_INST_IRQHandler(void)
{   
    //printf("I2C Interrupt Triggered to ADC!\n");
    switch (DL_I2C_getPendingInterrupt(I2C_controller_INST)) 
    {   /*START Condition*/
        case DL_I2C_IIDX_CONTROLLER_START:
            //gTxADCcount= 0;
            gRxADCcount= 0;
            DL_I2C_flushControllerTXFIFO(I2C_controller_INST);
            break;

        case DL_I2C_IIDX_CONTROLLER_RXFIFO_TRIGGER:
            gI2C.status= I2C_STATUS_RX_INPROGRESS;
            /* Store bytes received from target in Rx Msg Buffer */
            while (DL_I2C_isControllerRXFIFOEmpty(I2C_controller_INST) != true) {
                if (gRxADCcount< gRxADClen) {
                        gRxPacket[gRxADCcount] = DL_I2C_receiveControllerData(I2C_controller_INST);
                        printf("Received Byte[%d]: 0x%02X\n", gRxADCcount, gRxPacket[gRxADCcount]);  // Debug print
                        gRxADCcount++;
                                      
                } else {
                    //printf("ERROR: RX Buffer Overflow! ptr=%d MAX_BUFFER_SIZE=%d\n", gI2C.rxMsg.ptr, MAX_BUFFER_SIZE);
                    /* Ignore and remove from FIFO if the buffer is full */
                    DL_I2C_receiveControllerData(I2C_controller_INST);
                }
            }
            if (gRxADCcount >= gRxADClen){
                //printf("ADC Bytes Received!\n");
                gRxComplete = true;
                DL_I2C_enableInterrupt(I2C_controller_INST, DL_I2C_INTERRUPT_CONTROLLER_STOP);
                
            }
            break;
        /*TRANSMIT data to ADC*/
        case DL_I2C_IIDX_CONTROLLER_TXFIFO_TRIGGER:
            //printf("TX FIFO with data!\n"); 
            gI2C.status= I2C_STATUS_TX_INPROGRESS;
            if(gTxADCcount<gTxADClen){
                gTxADCcount+= DL_I2C_fillControllerTXFIFO(I2C_controller_INST, &gTxPacket[gTxADCcount], (gTxADClen-gTxADCcount));
            } else{
                /*Prevent overflow and just ignore data*/
                DL_I2C_fillTargetTXFIFO(I2C_controller_INST, (uint8_t[]){0x00}, 1);
                gTxComplete= true;
            }
            break;
        /*STOP condition*/
        case DL_I2C_IIDX_CONTROLLER_STOP:
            gTxComplete= true;
            gRxComplete = true;
            //printf("I2C Stop Detected- RX Complete");
            break;
        case DL_I2C_IIDX_CONTROLLER_ARBITRATION_LOST:
            //printf("Interrupt index for I2C controller Arbitration Lost!\n");
            break;
        case DL_I2C_IIDX_CONTROLLER_NACK:
            //printf("I2C NACK Received\n");
            if((gI2C.status== I2C_STATUS_RX_STARTED)|| (gI2C.status= I2C_STATUS_TX_STARTED)){
                gI2C.status= I2C_STATUS_ERROR;
            }
            break;
        default:
            break;
    }
}

/**** Interrupt for Pi to MCU ****/

void I2C_target_INST_IRQHandler(void) {

    //printf("I2C Interrupt Triggered to MCU (TARGET)!\n");
    uint8_t receivedCommand= 0;
    uint32_t status = DL_I2C_getPendingInterrupt(I2C_target_INST);
    //ADC_PARAMS params;
    switch (status) {

        /* START condition detected */
        case DL_I2C_IIDX_TARGET_START:
            piTxCount= 0;
            piRxCount= 0;
            piTxComplete= false;
            DL_I2C_flushTargetTXFIFO(I2C_target_INST);
            break;

        /* STOP condition detected */
        case DL_I2C_IIDX_TARGET_STOP:
            piTxComplete= true;
            piRxComplete = true;
            DL_I2C_flushTargetTXFIFO(I2C_target_INST);
            break;

        /* TX FIFO trigger (Pi is reading data from MCU) */
        /* GET battery status is triggered when command is 0x01
           - Pi on request of 0x01 will get a response of the battery status for all the slots
           - Battery_StateUpdate function is called, which in turn calls the Battery_ReadState funtion to set the state of the batteries
        -Pi on command of [0x02, slot_id] will GET the 'Battery Data' which is voltage, current and temperature for a given slot.
            - MCU reads the slot_id from Pi using DL_I2C_receiveTargetData()
            - piTxCount is set to 0
            - piTxLen is the sizeof BatteryData struct which is 7 bytes
            - If the requested slot is correct then:
                - battery pointer variable points to the memory of the requested slot
                - the values of voltage, current and temperature are then stored in battery_data struct
            - Once the values are in BatteryData struct we wait for the bus to be free
            - Next we send the BatteryData to Pi using DL_I2C_fillTargetRXFIFO()
            - Reset the RX counter for the next data.
        */
        case DL_I2C_IIDX_TARGET_TXFIFO_TRIGGER:
            printf("Pi GET data from MCU!\n");
            if(!DL_I2C_isTargetRXFIFOEmpty(I2C_target_INST)){
                receivedCommand= DL_I2C_receiveTargetData(I2C_target_INST);
                printf("Received Command: 0x%02X\n", receivedCommand);

                if (receivedCommand == CMD_GET_BATTERY_STATUS){
                    printf("Battery status received.\n");
                    //Battery_StateUpdate();
                    piTxCount= 0;
                    piTxLen= NUM_SLOTS;
                    piTxComplete = false;
                    // Prepare data to be sent to Pi:
                    for(uint8_t slot= 0; slot < NUM_SLOTS; slot++){
                        // Read the battery status for each slot
                        Battery_ReadState(slot);
                        piTxPacket[slot]= batteries[slot].state;
                    }
                    //Filling up the FIFO
                    if(piTxCount < piTxLen){
                        while (DL_I2C_getTargetStatus(I2C_target_INST) & DL_I2C_TARGET_STATUS_BUS_BUSY);
                        piTxCount += DL_I2C_fillTargetTXFIFO(I2C_target_INST, &piTxPacket[piTxCount], (piTxLen-piTxCount));     
                    }
                    else {
                    /*
                    * Fill FIFO with 0x00 if more data is requested than expected piTxLen
                    */
                    while (
                        DL_I2C_transmitTargetDataCheck(I2C_target_INST, 0x00) != false);
                    }
                    piTxComplete= true;
                }
                else if (receivedCommand == CMD_GET_BATTERY_DATA){

                    uint8_t requestedSlot= DL_I2C_receiveTargetData(I2C_target_INST);
                    while (DL_I2C_getTargetStatus(I2C_target_INST) & DL_I2C_TARGET_STATUS_BUS_BUSY);
                    printf("Battery Data Requested for Slot %d!\n", requestedSlot);
                        piTxCount= 0;
                        piTxLen= sizeof(BatteryData);
                        BatteryData battery_data;
                        if(requestedSlot < NUM_SLOTS){
                            Battery *battery= &batteries[requestedSlot];
                            battery_data.slot_id = battery-> slot_id;
                            battery_data.voltage= battery-> voltage;
                            battery_data.current= battery-> current;
                            battery_data.temperature= battery-> temperature;

                            while (DL_I2C_getTargetStatus(I2C_target_INST) & DL_I2C_TARGET_STATUS_BUS_BUSY);

                            DL_I2C_fillTargetTXFIFO(I2C_target_INST, (uint8_t *)&battery_data, sizeof(BatteryData));

                            //piTxCount += DL_I2C_fillTargetTXFIFO(I2C_target_INST, (uint8_t*)&battery_data, piTxLen);

                            piTxComplete= true;

                            while (DL_I2C_getTargetStatus(I2C_target_INST) & DL_I2C_TARGET_STATUS_BUS_BUSY);

                            if(piTxCount >= piTxLen){
                            piTxComplete= true;
                            piTxCount=0;
                            }

                        } else{
                            printf("Invalid Slot ID: %d\n.", requestedSlot);
                        }
                    
                }
        }
            
            break;

         /* TARGET_Rx FIFO trigger (Pi is writing data to MCU) */
         /*Pi SET battery data limits for each slot, where:
         - RXFIFO buffer is filled if the command from Pi is 0x03
         - Creating a temporary buffer named ´rxbuffer´
         - sizeof(BatteryLimitMsg): 11 bytes (1 byte: slot_id, 2 bytes: min_voltage; max_voltage; cut_off_current; capacitance; charge_fraction)
         - rx_buffer stores the data from Pi.
         - if all the expected bytes are received from Pi then,
            - memcpy() to copy the block of address from the temporary buffer to the BatteryLimitMsg structure
            - Why?, A: It copies the specified number of bytes from one memory location to another regardless of the type of the data stored.
            - verify if the received slot_id is less than NUM_SLOTS, where slot_id count starts from 0 then:
                - create a pointer variable for 'Battery' 
                - battery_limits.slot_id: index of the battery slot to be updated
                - &batteries[battery_limits.slot_id]: gets the memory address of the battery in that slot
                - Accessing the structure members of Battery using -> operator. This allows efficient access to the structure's members 
                without directly using the structure variable.

         */
        case DL_I2C_IIDX_TARGET_RXFIFO_TRIGGER:
            printf("Pi SET Battery limit to MCU.....\n");
            if(!DL_I2C_isTargetRXFIFOEmpty(I2C_target_INST)){
                receivedCommand= DL_I2C_receiveTargetData(I2C_target_INST);
                printf("Received Command: 0x%02X\n", receivedCommand);
                if(receivedCommand == CMD_SET_BATTERY_LIMIT){
                uint8_t rx_buffer[sizeof(BatteryLimitMsg)];
                uint8_t index= 0;

                while (!DL_I2C_isTargetRXFIFOEmpty(I2C_target_INST)){
                    if(index < sizeof(BatteryLimitMsg)){
                        rx_buffer[index]= DL_I2C_receiveTargetData(I2C_target_INST);
                        printf("Received Byte[%d]: 0x%02X\n", index, rx_buffer[index]); 
                        index++;
                        
                    }
                    else{
                        DL_I2C_receiveTargetData(I2C_target_INST);
                    }
                }

                printf("Total Bytes Received: %d (Expected: %d)\n", index, sizeof(BatteryLimitMsg));

                if(index == sizeof(BatteryLimitMsg)){
                    printf("Received Battery Limits.\n");
                    BatteryLimitMsg battery_limits;
                    memcpy(&battery_limits, rx_buffer, sizeof(BatteryLimitMsg));
                    if(battery_limits.slot_id < NUM_SLOTS){
                        Battery *battery = &batteries[battery_limits.slot_id];
                        battery -> min_voltage = battery_limits.min_voltage;
                        battery -> max_voltage = battery_limits.max_voltage;
                        battery -> cut_off_current = battery_limits.cut_off_current;
                        battery -> capacitance = battery_limits.capacitance;
                        battery -> charge_fraction = battery_limits.charge_fraction;
                        printf("\n Received Battery Limits for slot %d: \n", battery_limits.slot_id);
                        printf("  Min Voltage:      %d mV (0x%04X)\n", battery_limits.min_voltage, battery_limits.min_voltage);
                        printf("  Max Voltage:      %d mV (0x%04X)\n", battery_limits.max_voltage, battery_limits.max_voltage);
                        printf("  Cutoff Current:   %d mA (0x%04X)\n", battery_limits.cut_off_current, battery_limits.cut_off_current);
                        printf("  Capacitance:      %d µF (0x%04X)\n", battery_limits.capacitance, battery_limits.capacitance);
                        printf("  Charge Fraction:  %d%% (0x%02X)\n", battery_limits.charge_fraction, battery_limits.charge_fraction);
                    }
                }

                }

            }
            
            break;
    
        /* Arbitration lost or NACK */
        case DL_I2C_IIDX_TARGET_ARBITRATION_LOST:
            printf("Arbitration Lost.\n");
            break;
        default:
            printf("Unknown Interrupt.\n");
            break;
    }
}

/********MAIN function*************/

int main(void)
{
    // Initialize System and I2C
    SYSCFG_DL_init();

    // Initialize battery array and default params
    Battery_Init();
    
    //Reset_I2C_Bus();
    //NVIC_EnableIRQ(I2C_target_INST_INT_IRQN);
    NVIC_EnableIRQ(I2C_controller_INST_INT_IRQN);

    printf("............System Configuration Enabled...............\n");
    
    //Multiplexer
    Multiplexer_SelectChannel(I2C_CHANNEL);
    I2C_scanBus();
    I2C_init(&gI2C);

    // *Configure ADC for voltage: Channel 1 and Channel 2*
    /*ADC_PARAMS adc_voltage_params={
        .channel= 1,
        .resolution= 12,
        .continuous= 1,
        .gain= 1
    };
    
    ADC_PARAMS adc_current_params={
        .channel= 2,
        .resolution= 12,
        .continuous= 1,
        .gain= 1
    };*/
    
    
    //ADC_SetConfigurationBytes(adc_voltage_params); 
    //delay_cycles(50000);
    //ADC_SetConfigurationBytes(adc_current_params);
    //delay_cycles(50000);

    while (1)
    {   //Looping through the ADC Channels
        Battery_UpdateADCReading();
        delay_cycles(100000);
          
        //Battery_UpdateCurrent(adc_current_params);
        //delay_cycles(50000);

        //CC-CV Cycle: maximum cycles is not yet implemented
        //for(uint8_t slot_id= 0; slot_id < NUM_SLOTS; slot_id++){
        //    CC_CV_ControlCharging(slot_id);
        //}  

        //DAC_fastWrite(CHANNEL_A_VALUE);   

    }   

}