#include "raven_spn.h"
#include "spn_regs.h"
#include "delay.h"
#include "bsp.h"
#include "plic/plic_driver.h"

#include <cstdio>
#include <cstdint>
#include <array>
#include <cmath>

using spn =spn_regs<0x90000000>;

#define IOF_ENABLE_TERMINAL (0x30000)

// huge arrays of XSPN input and referance data
extern std::array<uint8_t, 50000> input_data;
extern std::array<double, 10000> ref_data;
constexpr auto ln2 = std::log(2);


typedef void (*function_ptr_t) (void);
//! Instance data for the PLIC.
plic_instance_t g_plic;
std::array<function_ptr_t,PLIC_NUM_INTERRUPTS>  g_ext_interrupt_handlers;


/*! \brief external interrupt handler
 *
 * routes the peripheral interrupts to the the respective handler
 *
 */
extern "C" void handle_m_ext_interrupt() {
    plic_source int_num  = PLIC_claim_interrupt(&g_plic);
    if ((int_num >=1 ) && (int_num < PLIC_NUM_INTERRUPTS))
      g_ext_interrupt_handlers[int_num]();
    else
      exit(1 + (uintptr_t) int_num);
    PLIC_complete_interrupt(&g_plic, int_num);
}
/*! \brief dummy interrupt handler
 *
 */
void no_interrupt_handler (void) {};
/*! \brief configure the per-interrupt handler
 *
 */
void configure_irq(size_t irq_num, function_ptr_t handler, unsigned char prio=1) {
    g_ext_interrupt_handlers[irq_num] = handler;
    // Priority must be set > 0 to trigger the interrupt.
    PLIC_set_priority(&g_plic, irq_num, prio);
    // Have to enable the interrupt both at the GPIO level, and at the PLIC level.
    PLIC_enable_interrupt(&g_plic, irq_num);
}

static void msi_interrupt_handler(){
    printf("INterrupt handler call\n");
}

/*!\brief initializes platform
 *
 */
void platform_init(){
	// UART init section TODO: clarify how to get the functions from init.c?
	GPIO_REG(GPIO_IOF_SEL) &= ~IOF0_UART0_MASK;
	GPIO_REG(GPIO_IOF_EN) |= IOF0_UART0_MASK;
	UART0_REG(UART_REG_TXCTRL) |= UART_TXEN;

    F_CPU=PRCI_measure_mcycle_freq(20, RTC_FREQ);
    printf("core freq at %d Hz\n", F_CPU);
    // initialie interupt & trap handling
    write_csr(mtvec, &trap_entry);

    PLIC_init(&g_plic, PLIC_CTRL_ADDR, PLIC_NUM_INTERRUPTS, PLIC_NUM_PRIORITIES, 0);
    // Disable the machine & timer interrupts until setup is done.
    clear_csr(mie, MIP_MEIP);
    clear_csr(mie, MIP_MTIP);
    for (auto& h:g_ext_interrupt_handlers) h=no_interrupt_handler;
    configure_irq(2, msi_interrupt_handler);
    // Enable interrupts in general.
    set_csr(mstatus, MSTATUS_MIE);
    // Enable the Machine-External bit in MIE
    set_csr(mie, MIP_MEIP);
}

bool double_equals(double a, double b, double epsilon = 0.001)
{
    return std::abs(a - b) < epsilon;
}

void run_xspn() {
	spn::mode_reg() = 0;
	spn::input_length_reg() = 100; 		// each sample consists of 5 uint8 values
	spn::input_addr_reg() = 0x800C0000;
	spn::output_addr_reg() = 0x8001C000;
	spn::num_of_in_beats_reg() = 8;		// Number of AXI4 burst beats needed to load all input data
	spn::num_of_out_beats_reg() = 13;	// Number of AXI4 burst beats needed to store all result data
	spn::start_reg() = 1;
	delayUS(50);
	spn::interrupt_reg() = 1;
}

/*! \brief main function
 *
 */
int main() {
    platform_init();
    spn::mode_reg() = 1;
    spn::start_reg() = 1;
    printf("READOUT HW:0x%x\n", spn::readout_reg());
    spn::interrupt_reg() = 1;

	for (int k = 0; k < 10000; k+=100) {
        // write input samples into the memory
        int * mem_base = (int *) 0x800C0000;
        int offset = k * 5;

        for(size_t i = 0, j = 0; j < 125; i += 4, j++) {
        	*(mem_base+j) = input_data.at(offset+i);
        	*(mem_base+j) |= (input_data.at(offset+i+1) << 8)  & 0x0000FF00;
        	*(mem_base+j) |= (input_data.at(offset+i+2) << 16) & 0x00FF0000;
        	*(mem_base+j) |= (input_data.at(offset+i+3) << 24) & 0xFF000000;
        }

        printf("XSPN process samples %d - %d\n", k, k+100);
    	run_xspn();

    	// read calculation results from the memory
        double * res_base = (double*) 0x8001C000;

        for (int i = 0; i < 100; i++) {
            if (!double_equals(res_base[i] * ln2, ref_data.at(k+i))) {
                printf("XSPN ref %d comparison FAILED\n", k+i);
            }
    	}

	}

	return 0;
}