#include <lunaix/common.h>
#include <lunaix/tty/tty.h>

#include <lunaix/mm/page.h>
#include <lunaix/mm/pmm.h>
#include <lunaix/mm/vmm.h>
#include <lunaix/mm/kalloc.h>
#include <lunaix/spike.h>
#include <lunaix/syslog.h>
#include <lunaix/timer.h>

#include <hal/rtc.h>
#include <hal/apic.h>
#include <hal/ioapic.h>
#include <hal/acpi/acpi.h>

#include <arch/x86/boot/multiboot.h>
#include <arch/x86/idt.h>
#include <arch/x86/interrupts.h>

#include <klibc/stdio.h>

#include <stdint.h>
#include <stddef.h>


extern uint8_t __kernel_start;
extern uint8_t __kernel_end;
extern uint8_t __init_hhk_end;


// Set remotely by kernel/asm/x86/prologue.S
multiboot_info_t* _k_init_mb_info;

LOG_MODULE("INIT");

void
setup_memory(multiboot_memory_map_t* map, size_t map_size);

void
setup_kernel_runtime();

void
lock_reserved_memory();

void
unlock_reserved_memory();

void
_kernel_pre_init() {
    _init_idt();
    intr_routine_init();

    pmm_init(MEM_1MB + (_k_init_mb_info->mem_upper << 10));
    vmm_init();
    rtc_init();

    tty_init((void*)VGA_BUFFER_PADDR);
    tty_set_theme(VGA_COLOR_WHITE, VGA_COLOR_BLACK);
}

void
_kernel_init() {
    kprintf("[MM] Mem: %d KiB, Extended Mem: %d KiB\n",
           _k_init_mb_info->mem_lower,
           _k_init_mb_info->mem_upper);

    unsigned int map_size = _k_init_mb_info->mmap_length / sizeof(multiboot_memory_map_t);
    
    setup_memory((multiboot_memory_map_t*)_k_init_mb_info->mmap_addr, map_size);

    setup_kernel_runtime();
}

void 
_kernel_post_init() {
    size_t hhk_init_pg_count = ((uintptr_t)(&__init_hhk_end)) >> PG_SIZE_BITS;
    kprintf(KINFO "[MM] Releaseing %d pages from 0x0.\n", hhk_init_pg_count);

    // Fuck it, I will no longer bother this little 1MiB
    // I just release 4 pages for my APIC & IOAPIC remappings
    for (size_t i = 0; i < 3; i++) {
        vmm_unmap_page((void*)(i << PG_SIZE_BITS));
    }
    
    // 锁定所有系统预留页（内存映射IO，ACPI之类的），并且进行1:1映射
    lock_reserved_memory();

    acpi_init(_k_init_mb_info);
    uintptr_t ioapic_addr = acpi_get_context()->madt.ioapic->ioapic_addr;

    pmm_mark_page_occupied(FLOOR(__APIC_BASE_PADDR, PG_SIZE_BITS));
    pmm_mark_page_occupied(FLOOR(ioapic_addr, PG_SIZE_BITS));

    vmm_set_mapping(APIC_BASE_VADDR, __APIC_BASE_PADDR, PG_PREM_RW);
    vmm_set_mapping(IOAPIC_BASE_VADDR, ioapic_addr, PG_PREM_RW);

    apic_init();
    ioapic_init();
    timer_init(SYS_TIMER_FREQUENCY_HZ);

    for (size_t i = 256; i < hhk_init_pg_count; i++) {
        vmm_unmap_page((void*)(i << PG_SIZE_BITS));
    }
}

void
lock_reserved_memory() {
    multiboot_memory_map_t* mmaps = _k_init_mb_info->mmap_addr;
    size_t map_size = _k_init_mb_info->mmap_length / sizeof(multiboot_memory_map_t);
    for (unsigned int i = 0; i < map_size; i++) {
        multiboot_memory_map_t mmap = mmaps[i];
        if (mmap.type == MULTIBOOT_MEMORY_AVAILABLE) {
            continue;
        }
        uint8_t* pa = PG_ALIGN(mmap.addr_low);
        size_t pg_num = CEIL(mmap.len_low, PG_SIZE_BITS);
        for (size_t j = 0; j < pg_num; j++)
        {
            vmm_set_mapping((pa + (j << PG_SIZE_BITS)), (pa + (j << PG_SIZE_BITS)), PG_PREM_R);
        }
    }
}

void
unlock_reserved_memory() {
    multiboot_memory_map_t* mmaps = _k_init_mb_info->mmap_addr;
    size_t map_size = _k_init_mb_info->mmap_length / sizeof(multiboot_memory_map_t);
    for (unsigned int i = 0; i < map_size; i++) {
        multiboot_memory_map_t mmap = mmaps[i];
        if (mmap.type == MULTIBOOT_MEMORY_AVAILABLE) {
            continue;
        }
        uint8_t* pa = PG_ALIGN(mmap.addr_low);
        size_t pg_num = CEIL(mmap.len_low, PG_SIZE_BITS);
        for (size_t j = 0; j < pg_num; j++)
        {
            vmm_unmap_page((pa + (j << PG_SIZE_BITS)));
        }
    }
}

// 按照 Memory map 标识可用的物理页
void
setup_memory(multiboot_memory_map_t* map, size_t map_size) {

    // First pass, to mark the physical pages
    for (unsigned int i = 0; i < map_size; i++) {
        multiboot_memory_map_t mmap = map[i];
        kprintf("[MM] Base: 0x%x, len: %u KiB, type: %u\n",
               map[i].addr_low,
               map[i].len_low >> 10,
               map[i].type);
        if (mmap.type == MULTIBOOT_MEMORY_AVAILABLE) {
            // 整数向上取整除法
            uintptr_t pg = map[i].addr_low + 0x0fffU;
            pmm_mark_chunk_free(pg >> PG_SIZE_BITS, map[i].len_low >> PG_SIZE_BITS);
            kprintf(KINFO "[MM] Freed %u pages start from 0x%x\n",
                   map[i].len_low >> PG_SIZE_BITS,
                   pg & ~0x0fffU);
        }
    }

    // 将内核占据的页，包括前1MB，hhk_init 设为已占用
    size_t pg_count = V2P(&__kernel_end) >> PG_SIZE_BITS;
    pmm_mark_chunk_occupied(0, pg_count);
    kprintf(KINFO "[MM] Allocated %d pages for kernel.\n", pg_count);


    size_t vga_buf_pgs = VGA_BUFFER_SIZE >> PG_SIZE_BITS;
    
    // 首先，标记VGA部分为已占用
    pmm_mark_chunk_occupied(VGA_BUFFER_PADDR >> PG_SIZE_BITS, vga_buf_pgs);
    
    // 重映射VGA文本缓冲区（以后会变成显存，i.e., framebuffer）
    for (size_t i = 0; i < vga_buf_pgs; i++)
    {
        vmm_map_page(
            (void*)(VGA_BUFFER_VADDR + (i << PG_SIZE_BITS)), 
            (void*)(VGA_BUFFER_PADDR + (i << PG_SIZE_BITS)), 
            PG_PREM_RW
        );
    }
    
    // 更新VGA缓冲区位置至虚拟地址
    tty_set_buffer((void*)VGA_BUFFER_VADDR);

    kprintf(KINFO "[MM] Mapped VGA to %p.\n", VGA_BUFFER_VADDR);
    
}

void
setup_kernel_runtime() {
    // 为内核创建一个专属栈空间。
    for (size_t i = 0; i < (K_STACK_SIZE >> PG_SIZE_BITS); i++) {
        vmm_alloc_page((void*)(K_STACK_START + (i << PG_SIZE_BITS)), PG_PREM_RW);
    }
    kprintf(KINFO "[MM] Allocated %d pages for stack start at %p\n", K_STACK_SIZE>>PG_SIZE_BITS, K_STACK_START);
    assert_msg(kalloc_init(), "Fail to initialize heap");
}