#include <stdint.h>
#include "ext2.h"
#include "lib/logger/log.h"

#define FOOLOS_MODULE_NAME "elf"
#define EI_NIDENT 16


typedef uint32_t Elf32_Addr;
typedef uint32_t Elf32_Off;
typedef uint16_t Elf32_Section;
typedef uint16_t Elf32_Versym;
typedef unsigned char Elf_Byte;
typedef uint16_t Elf32_Half;
typedef int32_t Elf32_Sword;
typedef uint32_t Elf32_Word;
typedef int64_t Elf32_Sxword;
typedef uint64_t Elf32_Xword;


typedef struct
{

        unsigned char   e_ident[EI_NIDENT];
        Elf32_Half      e_type;
        Elf32_Half      e_machine;
        Elf32_Word      e_version;
        Elf32_Addr      e_entry;
        Elf32_Off       e_phoff;
        Elf32_Off       e_shoff;
        Elf32_Word      e_flags;
        Elf32_Half      e_ehsize;
        Elf32_Half      e_phentsize;
        Elf32_Half      e_phnum;
        Elf32_Half      e_shentsize;
        Elf32_Half      e_shnum;
        Elf32_Half      e_shstrndx;

}
Elf32_Ehdr;


typedef struct {
       Elf32_Word      sh_name;
       Elf32_Word      sh_type;
       Elf32_Word      sh_flags;
       Elf32_Addr      sh_addr;
       Elf32_Off       sh_offset;
       Elf32_Word      sh_size;
       Elf32_Word      sh_link;
       Elf32_Word      sh_info;
       Elf32_Word      sh_addralign;
       Elf32_Word      sh_entsize;
} Elf32_Shdr;

typedef struct {

       Elf32_Word      p_type;
       Elf32_Off       p_offset;
       Elf32_Addr      p_vaddr;
       Elf32_Addr      p_paddr;
       Elf32_Word      p_filesz;
       Elf32_Word      p_memsz;
       Elf32_Word      p_flags;
       Elf32_Word      p_align;
} 
Elf32_Phdr;

// returns elf entry point
uint32_t load_elf(char *name, uint32_t *alloc)
{
    uint32_t ext2_ramimage= fs_get_root_ext2_ramimage();

    int inode_nr=ext2_filename_to_inode(ext2_ramimage,name);
    if(inode_nr<1)return 0;

    //TODO: load ELF binary and move this to own compilation unit
    
    //load binary
//    uint32_t vaddr=0x08048000;
    uint32_t vaddr=0x08000000;

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"loading %s",name);
    ext2_check(ext2_ramimage);
    ext2_inode_content(ext2_ramimage,inode_nr,vaddr,0x100000); // load 1mb;
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"ELF File loaded to final destination.");

    Elf32_Ehdr *elf;
    elf=vaddr;

    if(elf->e_ident[0]!=0x7f||elf->e_ident[1]!='E'||elf->e_ident[2]!='L'||elf->e_ident[3]!='F')
	panic(FOOLOS_MODULE_NAME,"ELF mismatch!?");

    
    /*
    log(FOOLOS_MODULE_NAME, FOOLOS_LOG_INFO, 
	    "elf id: class=%d, data=%d, version=%d osabi=%d abiv=%d ",
	    elf->e_ident[4],elf->e_ident[5],elf->e_ident[6],
	    elf->e_ident[7],elf->e_ident[8]);

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf type: 0x%04x",elf->e_type);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf machine: 0x%04x",elf->e_machine);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf version: %d",elf->e_version);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf entry: 0x%08X",elf->e_entry);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf ph-offset: 0x%08X",elf->e_phoff);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf sh-offset: 0x%08X",elf->e_shoff);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf flags: 0x%08X",elf->e_flags);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf eh-size (bytes): %d",elf->e_ehsize);

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf ph-ent-size(bytes): %d",elf->e_phentsize);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf ph-num: %d",elf->e_phnum);

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf sh-ent-size(byte): %d",elf->e_shentsize);
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf sh-num: %d",elf->e_shnum);

    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"elf sh-strndx: %d",elf->e_shstrndx);
    */

    // iterate over section headers
    for(int phidx=0;phidx<elf->e_phnum;phidx++)
    {	
	Elf32_Phdr *phdr=vaddr+elf->e_phoff+phidx*elf->e_phentsize;

	if(phidx==0)
	{
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"text: 0x%08X-0x%08X",phdr->p_vaddr,phdr->p_vaddr+phdr->p_filesz);
	}

	if(phidx==1)
	{


	    /*
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"-- PROGRAMM HEADER %d --",phidx+1);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"p-type: %d",phdr->p_type);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"p-offset: 0x%08X",phdr->p_offset);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"p-vaddr: 0x%08X",phdr->p_vaddr);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"p-filesz: 0x%08X",phdr->p_filesz);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"p-memsz: 0x%08X",phdr->p_memsz);
	    */
	    
	    
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"data: 0x%08X-0x%08X",phdr->p_vaddr,phdr->p_vaddr+phdr->p_filesz);
	    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_DEBUG,"bss: 0x%08X-0x%08X",phdr->p_vaddr+phdr->p_filesz,phdr->p_vaddr+phdr->p_memsz);

	    // let's copy the rw- data block
	    uint32_t *data=vaddr+phdr->p_offset;
	    for(uint32_t *addr=phdr->p_vaddr; addr<=phdr->p_vaddr+phdr->p_filesz; addr++)
	    {
		*addr=*data;
		data++;
	    }

	    // let's zero init bss and set alloc (heap) just right after it! 
	    for(uint32_t *addr=phdr->p_vaddr+phdr->p_filesz; addr<=phdr->p_vaddr+phdr->p_memsz; addr++)
	    {
		*addr=0;
	    }

	    *alloc=phdr->p_vaddr+phdr->p_memsz;
	}


    }

    return elf->e_entry;

}