#include "../kernel/vfs.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <klog.h>

static char** names;
static uint32_t* offsets;
static long* sizes;
static uint32_t num_files;
static FILE* initrd_fd;

static char drv(fs_op op,FILE* stream,void* data1,void* data2) {
  if (op==FSOP_MOUNT) {
    return 1;
  }
  if (op==FSOP_OPEN) {
    char file_exists=0;
    for (uint32_t i=0;i<num_files;i++) {
      if (strcmp(names[i],stream->path)==0) {
        file_exists=1;
      }
    }
    return file_exists;
  }
  if (op==FSOP_GETC) {
    uint32_t i;
    for (i=0;i<num_files;i++) {
      if (strcmp(names[i],stream->path)==0) {
        break;
      }
    }
    if (stream->pos>=sizes[i]) {
      *((int*)data1)=EOF;
      stream->eof=1;
      return 1;
    }
    fseek(initrd_fd,offsets[i]+stream->pos,SEEK_SET);
    *((int*)data1)=fgetc(initrd_fd);
    stream->pos+=1;
    return 1;
  }
  if (op==FSOP_CLOSE) {
    return 1;
  }
  return 0;
}

void initrd_init() {
  initrd_fd=fopen("/dev/initrd","r");
  if (!initrd_fd) {
    klog("PANIC","Cannot open initrd!");
    for(;;) {}
  }
  uint32_t max_files=32;
  num_files=0;
  names=malloc(sizeof(char*)*32);
  offsets=malloc(sizeof(uint32_t)*32);
  sizes=malloc(sizeof(long)*32);
  for (uint32_t i=0;;i++) {
      if (i==max_files) {
        names=realloc(names,sizeof(char*)*(max_files+32));
        offsets=realloc(offsets,sizeof(uint32_t)*(max_files+32));
        sizes=realloc(sizes,sizeof(long)*(max_files+32));
        max_files+=32;
      }
      uint32_t name_size;
      fread(&name_size,4,1,initrd_fd);
      if (name_size==0) {
        break;
      }
      char* name=malloc(sizeof(char)*(name_size+1));
      fread(name,1,name_size+1,initrd_fd);
      long contents_size;
      fread(&contents_size,4,1,initrd_fd);
      long datapos=ftell(initrd_fd);
      fseek(initrd_fd,contents_size,SEEK_CUR);
      names[i]=name;
      offsets[i]=datapos;
      sizes[i]=contents_size;
      num_files++;
  }
  fseek(initrd_fd,0,SEEK_SET);
  register_fs(drv,"initrd");
}