#include <memory/physical.h>
#include <memory/virtual.h>
#include <memory/addresses.h>
#include <disk/disk.h>
//#include <disk/filesys.h>
#include <screen/gfxmode.h>

#include <fs/fs.h>

uint8_t loadFile(char* filename, void* dest);

__attribute__ ((section("entry")))
void main() {
    // Physical memory manager setup
    uint32_t smapEntryCount = *(uint32_t*)SMAP_ENTRY_COUNT;
    smapEntry_t* smapEntries = (smapEntry_t*)SMAP_ENTRIES;
    smapEntries += smapEntryCount - 1;
    uint32_t totalMemory = smapEntries->baseAddress + smapEntries->length - 1;

    setupPhysicalMemoryManager(MEMMAP_AREA, totalMemory);

    smapEntries = (smapEntry_t*)SMAP_ENTRIES;
    for (uint32_t i = 0; i < smapEntryCount; i++) {
        if (smapEntries[i].type == 1) {
            initMemoryRegion(smapEntries[i].baseAddress, smapEntries[i].length);
        }
    }

    deinitMemoryRegion(0x1000, 0x11000); // Reserve kernel memory (under 0x12000)
    deinitMemoryRegion(MEMMAP_AREA, maxBlocks / BLOCKS_PER_BYTE);

    // Load root dir, find kernel INode and parse it
    superBlock_t* superblock = (superBlock_t*)SUPERBLOCK_LOC;
    superblock->rootInodePtr = BOOT_FIRST_INODE_LOC + sizeof(inode_t);
    diskRead(superblock->firstDataBlock * 8, 8, (void*)SCRATCH_BLOCK_LOC);

    if (loadFile("kernel.bin", (void*)KERNEL_LOC) != 0) __asm__ volatile ("cli; hlt" : : "a"(0xDeadBeef));
    if (loadFile("term16n.fnt", (void*)FONT_LOC) != 0) __asm__ volatile ("cli; hlt" : : "a"(0xDeadBeef));

    // Virtual memory manager setup
    if (setupVirtualMemoryManager() != 0) {
        while (1);
    }

    // Identity map VBE framebuffer
    uint32_t fbSize = (gfxMode->yRes * gfxMode->linearBytesPerScanline) / PAGE_SIZE;
    if (fbSize % PAGE_SIZE > 0) { fbSize++; }
    fbSize *= 2; // Double for hardware
    for (uint32_t i = 0, fbStart = gfxMode->physicalBasePtr; i < fbSize; i++, fbStart += PAGE_SIZE) {
        mapPage((void*)fbStart, (void*)fbStart);
    }
    deinitMemoryRegion(gfxMode->physicalBasePtr, fbSize * BLOCK_SIZE);

    *(uint32_t*)PHYS_MEM_MAX_BLOCKS = maxBlocks;
    *(uint32_t*)PHYS_MEM_USED_BLOCKS = usedBlocks;

    for (uint32_t virt = KERNEL_LOC; virt < 0x400000; virt += PAGE_SIZE) {
        unmapPage((void*)virt);
    }

    __asm__ volatile ("movl %cr3, %ecx; movl %ecx, %cr3");

    *(uint32_t*)CURRENT_PAGE_DIR_ADDR = (uint32_t)currentPd;

    // Call/jump to kernel
    ((void(*)(void))0xC0000000)();
}

uint8_t loadFile(char* filename, void* dest) {
    dirEntry_t* dirEntry = (dirEntry_t*)SCRATCH_BLOCK_LOC;
    while (dirEntry->name[0] != '\0') {
        if (strcmp(dirEntry->name, filename) == 0) break;
        dirEntry++;
    }

    if (dirEntry->name[0] == '\0') return 1;

    inode_t* inode = (inode_t*)BOOT_FIRST_INODE_LOC;
    while (inode->id != dirEntry->id) {
        inode++;
    }

    uint32_t totalBlocks = bytesToBlocks(inode->sizeBytes);
    uint32_t addressOffset = 0;

    for (uint8_t i = 0; i < 4 && totalBlocks > 0; i++) {
        diskRead(inode->extent[i].firstBlock * 8, inode->extent[i].length * 8, dest + addressOffset);
        addressOffset += inode->extent[i].length * FS_BLOCK_SIZE;
        totalBlocks -= inode->extent[i].length;
    }

    if (totalBlocks > 0) {
        // TODO: Indirect extents
    }

    return 0;
}