#include "../include/acpi.h"
#include "../include/graphics.h"
#include "../include/memory.h"
#include "../include/io.h"
#include "../include/timer.h"

struct FADT *fadt;
struct DSDT_vals dsdt;
void *dsdt_ptr;

void *findRSDP() {
    printf("ACPI: searching RSDP");
    uint8_t * mem = (uint8_t * )
    0x000E0000;
    while ((unsigned int) mem != 0x000FFFFF) {
        if (memcmp(mem, "RSD PTR ", 8) == 0) {
            uint8_t * bptr = (uint8_t * )
            mem;
            uint8_t check = 0;
            for (unsigned int i = 0; i < sizeof(struct RSDPDescriptor); i++) {
                check += *bptr;
                bptr++;
            }
            if (((struct RSDPDescriptor *) mem)->Revision >= 1) {
                check = 0;
                uint8_t * bptr20 = (uint8_t * )
                mem;
                for (unsigned int j = 0; j < sizeof(struct RSDPDescriptor20); j++) {
                    check += *bptr20;
                    bptr20++;
                }
            }
            if (!check) {
                printf("Done, RSDP found on 0x%08x", mem);
                return mem;
            } else {
                printf("error: ACPI RSDP checksum is invalid.");
            }
        }
        mem++;
    }
    printf("RSDP not found.");
    return 0;
}

int acpi_check_hdr(uint8_t *table, const char *sig, int n) {
    if (memcmp(table, sig, n) != 0)
        return 1;
    uint8_t checksum = 0;
    if (checksum == 0)
        return 0;
    return 1;
}

void parse_dsdt() {
    if (fadt == 0) {
        printf("ACPI: FADT not found!");
    }
    if (acpi_check_hdr((uint8_t * )(int)fadt->Dsdt, "DSDT", 4)!=0){
        printf("ACPI: Invalid DSDT signature!");
    }
    dsdt_ptr = (void *) fadt->Dsdt;
    dsdt.length = ((struct ACPISDTHeader *) dsdt_ptr)->Length - sizeof(struct ACPISDTHeader);
    int i;
    for (i = 0; i <= dsdt.length; i++) {
        if (memcmp(dsdt_ptr + sizeof(struct ACPISDTHeader) + i, "_S5_", 4) == 0) {
            dsdt.S5_object = dsdt_ptr + i;
            break;
        }
    }
    if (i == dsdt.length) {
        printf("ACPI: No S5 object in DSDT.");
    }
}

void parse_acpi(void *mem) {
    struct RSDPDescriptor *rsdp = mem;
    struct RSDT *rsdt = (struct RSDT *) (rsdp->RsdtAddress);
    int i = 0;
    if (acpi_check_hdr((uint8_t * )(int)rsdt, "RSDT", 4)!=0)
    {
        printf("ACPI: Invalid RSDT signature.");
    }
    while (acpi_check_hdr((uint8_t * )(&rsdt->PointerToOtherSDT)[i], "FACP", 4) != 0 && i <= 64)
        i++;
    if (i < 64) {
        fadt = (struct FADT *) (&rsdt->PointerToOtherSDT)[i];
    } else {
        printf("ACPI: FADT not found!");
    }
    const char *pm_profile_strings[9] = {"unspecified", "desktop", "notebook", "mobile", "workstation",
                                         "enterprice server", "SOHO server", "appliance PC", "perfomance server"};
    printf("This PC's power management profile is %s",
           (fadt->PreferredPowerManagementProfile < 8) ? pm_profile_strings[fadt->PreferredPowerManagementProfile]
                                                       : "unknown, field is in reserved value");
    //Then parse the DSDT and enable ACPI.
    parse_dsdt();
    acpi_enable();
}

void parse_acpi20(void *mem) {
    struct RSDPDescriptor20 *rsdp = (struct RSDPDescriptor20 *) mem;
    struct XSDT *xsdt = (struct XSDT *) (int) (rsdp->XsdtAddress);
    int i = 0;
    while (acpi_check_hdr((uint8_t * )(int)(&xsdt->PointerToOtherSDT)[i], "FACP", 4)!=0 && i <= 64)
    i++;
    if (i < 64) {
        fadt = (struct FADT *) (int) (&xsdt->PointerToOtherSDT)[i];
    } else {
        printf("ACPI: FADT not found!");
    }
    parse_dsdt();
    acpi_enable();
}

void acpi_enable() {
    printf("ACPI: Trying to enable ACPI...");
    if ((inw(fadt->PM1aControlBlock) >> 1 & 1) == 0) {
        printf("ACPI already enabled");
        return;
    }
    outb(fadt->SMI_CommandPort, fadt->AcpiEnable);
    int i;
    for (i = 0; i < 300; i++) {
        if ((inw(fadt->PM1aControlBlock) & 1) == 0)
            break;
        clock_sleep(4);
    }
    if ((inw(fadt->PM1aControlBlock) & 1) != 0) {
        printf("Failed to enable ACPI.");
    }
    printf("ACPI: ACPI enabled!");
}

void init_acpi() {
    struct RSDPDescriptor *rsdp = findRSDP();
    if (rsdp == NULL) {
        printf("\nNo ACPI on this computer.");
    }
    if (rsdp->Revision >= 1) {
        parse_acpi20((void *) rsdp);
        return;
    }
    parse_acpi((void *) rsdp);
}