/*
Copyright 2017-2023 Ian Jauslin

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#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;
}