#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "io.h"
#include "navier-stokes.h"

// write complex vector indexed by k1,k2 to file
int write_vec(_Complex double* vec, int K1, int K2, FILE* file){
  int kx,ky;

  // do nothing if there is no file
  if(file==NULL){
    return 0;
  }

  for(kx=0;kx<=K1;kx++){
    for(ky=(kx>0 ? -K2 : 1);ky<=K2;ky++){
      fprintf(file,"% 3d % 3d % .15e % .15e\n",kx,ky,__real__ vec[klookup_sym(kx,ky,K2)],__imag__ vec[klookup_sym(kx,ky,K2)]);
    }
  }

  return 0;
}

// write complex vector indexed by k1,k2 to file in binary format
int write_vec_bin(_Complex double* vec, int K1, int K2, FILE* file){
  // do nothing if there is no file
  if(file==NULL){
    return 0;
  }

  fwrite(vec, sizeof(_Complex double), K1*(2*K2+1)+K2, file);

  return 0;
}

// read complex vector indexed by k1,k2 from file
int read_vec(_Complex double* out, int K1, int K2, FILE* file){
  int kx,ky;
  double r,i;
  char* line;
  unsigned int len=256;
  unsigned int pos=0;
  char* line_realloc;
  char c;
  int ret;
  unsigned int counter=0;
  bool commented=false;

  // error if there is no file (this should not happen)
  if (file==NULL){
    fprintf(stderr,"error reading input from file (this is a bug, contact Ian at ian.jauslin@rutgers.edu!)\n");
    return -1;
  }

  // allocate line buffer
  line=calloc(sizeof(char), len);

  while(1){
    c=fgetc(file);

    // end of file
    if (feof(file)){
      break;
    }

    // newline: read line and reset buffer
    if(c=='\n' || c=='\r'){
      // increment line counter
      counter++;

      // read entry
      // ignore empty lines
      if(pos>0){
	ret=sscanf(line, "%d %d %le %le", &kx, &ky, &r, &i);

	// errors
	if(ret!=4){
	  fprintf(stderr, "warning: line %d does not match the input format: '%s', skipping\n", counter, line);
	}
	else{
	  if(kx>K1 || kx<-K1 || ky>K2 || ky<-K2){
	    fprintf(stderr, "warning: reading line %d: kx or ky out of bounds: %d,%d, skipping\n", counter, kx, ky);
	  }
	  else if (kx<0){
	    fprintf(stderr, "warning: reading line %d: kx should be >=0, got %d, skipping\n", counter, kx);
	  }
	  else if (kx==0 && ky<=0){
	    fprintf(stderr, "warning: reading line %d: if kx==0 then ky should be >0, got kx=%d ky=%d, skipping\n", counter, kx, ky);
	  }
	  else{
	    // set output
	    out[klookup_sym(kx, ky, K2)]=r+i*I;
	  }
	}
      }

      // reset buffer
      pos=0;
      line[pos]='\0';
      commented=false;
    }
    // comment: stop reading
    else if (c=='#'){
      commented=true;
    }
    // add to buffer (unless we are in a comment)
    else if (!(commented)){
      // check that there is room in buffer
      if(pos==len){
	// too short: reallocate
	line_realloc=calloc(sizeof(char), 2*len);
	for(pos=0;pos<len;pos++){
	  line_realloc[pos]=line[pos];
	}
	free(line);
	line=line_realloc;
	len=2*len;
      }

      // add c to line
      line[pos]=c;
      pos++;
      line[pos]='\0';
    }
  }

  free(line);

  return 0;
}

// read complex vector indexed by k1,k2 from file in binary format
int read_vec_bin(_Complex double* out, int K1, int K2, FILE* file){
  char c;
  int ret;

  // do nothing if there is no file
  if(file==NULL){
    return 0;
  }

  // seek past initial comments
  while(true){
    ret=fscanf(file, "%c", &c);
    if (ret==1 && c=='#'){
      // find endline
      while(true){
	ret=fscanf(file, "%c", &c);
	// end of file
	if (ret==0) {
	  // no data
	  return 0;
	}

	if (c=='\n'){
	  break;
	}
      }
    } else {
      if (ret==1){
	// backtrack
	fseek(file, -sizeof(char), SEEK_CUR);
      }
      // past comments
      break;
    }
  }

  fread(out, sizeof(_Complex double), K1*(2*K2+1)+K2, file);

  return 0;
}

// remove an entry from params string (inplace)
int remove_entry(
  char* param_str,
  char* entry
){
  char* ptr;
  char* rw_ptr;
  char* bfr;
  char* entry_ptr=entry;
  int go=1;

  for(ptr=param_str, rw_ptr=ptr; *ptr!='\0'; ptr++){
    for(bfr=ptr,entry_ptr=entry; *bfr==*entry_ptr; bfr++, entry_ptr++){
      // check if reached end of entry
      if(*(bfr+1)=='=' && *(entry_ptr+1)=='\0'){
	go=0;
	break;
      }
    }
    if(go==1){
      *rw_ptr=*ptr;
      rw_ptr++;
    }
    //reset
    if(*ptr==';'){
      go=1;
    }
  }
  *rw_ptr='\0';

  // remove trailing ';'
  if (param_str[strlen(param_str)-1]==';'){
    *(param_str+(strlen(param_str)-1))='\0';
  }

  return 0;
}