#include "dolphin/os/OS.h"
#include "dolphin/os/OSReboot.h"

static void* SaveStart = NULL;
static void* SaveEnd = NULL;
static volatile BOOL Prepared;

extern u32 OS_RESET_CODE AT_ADDRESS(0x800030F0);
extern u8 OS_REBOOT_BOOL AT_ADDRESS(0x800030E2); // unknown function, set to true by __OSReboot
extern u32 UNK_817FFFF8 AT_ADDRESS(0x817FFFF8);
extern u32 UNK_817FFFFC AT_ADDRESS(0x817FFFFC);

#define OS_BOOTROM_ADDR 0x81300000

typedef struct _ApploaderHeader {
    /* 0x00 */ char date[16];
    /* 0x10 */ u32 entry;
    /* 0x14 */ u32 size;
    /* 0x18 */ u32 rebootSize;
    /* 0x1C */ u32 reserved2;
} ApploaderHeader; // Size: 0x20

static ApploaderHeader Header ALIGN_DECL(32);

ASM static void Run(register u32 addr) {
    nofralloc

    sync
    isync
    mtlr addr
    blr
}

void ReadApploader(DVDCommandBlock* dvdCmd, void* addr, u32 offset, u32 numBytes);

void ReadApploader(DVDCommandBlock* dvdCmd, void* addr, u32 offset, u32 numBytes) {
    /* Not sure if this inline is correct - might need to call other inlines */
    while (Prepared == FALSE) {
    }
    DVDReadAbsAsyncForBS(dvdCmd, addr, numBytes, offset + 0x2440, NULL);

    while (TRUE) {
        switch (dvdCmd->state) {
        case 0:
            break;
        case 1:
        default:
            continue;
        case -1:
        case 2:
        case 3:
        case 4:
        case 5:
        case 6:
        case 7:
        case 8:
        case 9:
        case 10:
        case 11:
            __OSDoHotReset(UNK_817FFFFC);
            continue;
        }
        break;
    }
}

static void Callback(s32 result, struct DVDCommandBlock* block) { Prepared = TRUE; }

void __OSReboot(u32 resetCode, u32 bootDol) {
    OSContext exceptionContext;
    DVDCommandBlock dvdCmd;
    DVDCommandBlock dvdCmd2;
    u32 numBytes;
    u32 offset;

    OSDisableInterrupts();

    UNK_817FFFFC = 0;
    UNK_817FFFF8 = 0;
    OS_REBOOT_BOOL = TRUE;
    BOOT_REGION_START = (u32)SaveStart;
    BOOT_REGION_END = (u32)SaveEnd;
    OSClearContext(&exceptionContext);
    OSSetCurrentContext(&exceptionContext);
    DVDInit();
    DVDSetAutoInvalidation(TRUE);

    __DVDPrepareResetAsync(Callback);

    if (!DVDCheckDisk()) {
        __OSDoHotReset(UNK_817FFFFC);
    }

    __OSMaskInterrupts(0xffffffe0);
    __OSUnmaskInterrupts(0x400);

    OSEnableInterrupts();

    offset = 0;
    numBytes = 32;
    ReadApploader(&dvdCmd, (void*)&Header, offset, numBytes);

    offset = Header.size + 0x20;
    numBytes = OSRoundUp32B(Header.rebootSize);
    ReadApploader(&dvdCmd2, (void*)(OS_BOOTROM_ADDR), offset, numBytes);

    ICInvalidateRange((void*)(OS_BOOTROM_ADDR), numBytes);
    OSDisableInterrupts();
    ICFlashInvalidate();
    Run(OS_BOOTROM_ADDR);
}

void OSSetSaveRegion(void* start, void* end) {
    SaveStart = start;
    SaveEnd = end;
}