#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#include "system.h"
#include "config.h"


// buffered stream for reading lines, should perhaps be something smaller
typedef struct
{
	char buffer[4*1024];
	unsigned buffer_pos;
	unsigned buffer_size;
	unsigned buffer_max_size;
	IOHANDLE io;
} LINEREADER;

void linereader_init(LINEREADER *lr, IOHANDLE io)
{
	lr->buffer_max_size = 4*1024;
	lr->buffer_size = 0;
	lr->buffer_pos = 0;
	lr->io = io;
}

char *linereader_get(LINEREADER *lr)
{
	unsigned line_start = lr->buffer_pos;

	while(1)
	{
		if(lr->buffer_pos >= lr->buffer_size)
		{
			// fetch more

			// move the remaining part to the front
			unsigned left = lr->buffer_size - line_start;
			if(line_start > lr->buffer_size)
				left = 0;
			if(left)
				mem_move(lr->buffer, &lr->buffer[line_start], left);
			lr->buffer_pos = left;

			// fill the buffer
			unsigned read = io_read(lr->io, &lr->buffer[lr->buffer_pos], lr->buffer_max_size-lr->buffer_pos);
			lr->buffer_size = left + read;
			line_start = 0;

			if(!read)
			{
				if(left)
				{
					lr->buffer[left] = 0; // return the last line
					lr->buffer_pos = left;
					lr->buffer_size = left;
					return lr->buffer;
				}
				else
					return 0x0; // we are done!
			}
		}
		else
		{
			if(lr->buffer[lr->buffer_pos] == '\n' || lr->buffer[lr->buffer_pos] == '\r')
			{
				// line found
				lr->buffer[lr->buffer_pos] = 0;
				lr->buffer_pos++;
				return &lr->buffer[line_start];
			}
			else
				lr->buffer_pos++;
		}
	}
}

CONFIGURATION config;

void config_reset()
{
    #define MACRO_CONFIG_INT(name,def,min,max) config.name = def;
    #define MACRO_CONFIG_STR(name,len,def) strncpy(config.name, def, len);
 
    #include "config_variables.h" 
 
    #undef MACRO_CONFIG_INT 
    #undef MACRO_CONFIG_STR 
}

void strip_spaces(char **p)
{
	char *s = *p;
	
	while (*s == ' ')
		++s;

	char *end = s + strlen(s);
	while (end > s && *(end - 1) == ' ')
		*--end = 0;
}

void config_set(const char *line)
{
	const char *c = strchr(line, '=');
	if (c)
	{
		char var[256];
		char val[256];

		strcpy(val, c+1);

		mem_copy(var, line, c - line);
		var[c - line] = 0;

		char *var_str = var;
		char *val_str = val;

		strip_spaces(&var_str);
		strip_spaces(&val_str);

		#define MACRO_CONFIG_INT(name,def,min,max) { if (strcmp(#name, var_str) == 0) config_set_ ## name (&config, atoi(val_str)); }
    	#define MACRO_CONFIG_STR(name,len,def) { if (strcmp(#name, var_str) == 0) { config_set_ ## name (&config, val_str); } }
 
    	#include "config_variables.h" 
 
    	#undef MACRO_CONFIG_INT 
    	#undef MACRO_CONFIG_STR 
	}
}

void config_load(const char *filename)
{
	char full_path[1024];
	if (filename[0] == '~')
	{
		char *home = getenv("HOME");
		if (home)
		{
			sprintf(full_path, "%s%s", home, filename+1);
			filename = full_path;
		}
	}

	dbg_msg("config/load", "loading %s", filename);

	IOHANDLE file = io_open(filename, IOFLAG_READ);
	
	if(file)
	{
		char *line;
		LINEREADER lr;
		linereader_init(&lr, file);

		while ((line = linereader_get(&lr)))
			config_set(line);

		io_close(file);
	}
}

void config_save(const char *filename)
{
	char full_path[1024];
	if (filename[0] == '~')
	{
		char *home = getenv("HOME");
		if (home)
		{
			sprintf(full_path, "%s%s", home, filename+1);
			filename = full_path;
		}
	}


	dbg_msg("config/save", "saving config to %s", filename);

	//file_stream file;
	IOHANDLE file = io_open(filename, IOFLAG_WRITE);

	if(file)
	{
#if defined(CONF_FAMILY_WINDOWS)
		const char newline[] = "\r\n";
#else
		const char newline[] = "\n";
#endif
		const int newline_len = sizeof(newline)-1;
		
    	#define MACRO_CONFIG_INT(name,def,min,max) { char str[256]; sprintf(str, "%s=%i%s", #name, config.name, newline); io_write(file, str, strlen(str)); }
    	#define MACRO_CONFIG_STR(name,len,def) { io_write(file, #name, strlen(#name)); io_write(file, "=", 1); io_write(file, config.name, strlen(config.name)); io_write(file, newline, newline_len); }
 
    	#include "config_variables.h" 
 
    	#undef MACRO_CONFIG_INT 
    	#undef MACRO_CONFIG_STR 

		io_close(file);
	}
	else
		dbg_msg("config/save", "couldn't open %s for writing. :(", filename);
}

#define MACRO_CONFIG_INT(name,def,min,max) int config_get_ ## name (CONFIGURATION *c) { return c->name; }
#define MACRO_CONFIG_STR(name,len,def) const char *config_get_ ## name (CONFIGURATION *c) { return c->name; }
#include "config_variables.h"
#undef MACRO_CONFIG_INT
#undef MACRO_CONFIG_STR

#define MACRO_CONFIG_INT(name,def,min,max) void config_set_ ## name (CONFIGURATION *c, int val) { if (val < min) val = min; if (max != 0 && val > max) val = max; c->name = val; }
#define MACRO_CONFIG_STR(name,len,def) void config_set_ ## name (CONFIGURATION *c, const char *str) { strncpy(c->name, str, len-1); c->name[sizeof(c->name)-1] = 0; }
#include "config_variables.h"
#undef MACRO_CONFIG_INT
#undef MACRO_CONFIG_STR