/* ScummVM - Scumm Interpreter
 * Copyright (C) 2004 The ScummVM project
 *
 * The ReInherit Engine is (C)2000-2003 by Daniel Balsom.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header$
 *
 */

// Configuration Variable Module
#include "saga.h"
#include "reinherit.h"

#include "console_mod.h"

#include "cvar_mod.h"
#include "cvar.h"

namespace Saga {

R_CVAR *CVHashTbl[R_CVAR_HASHLEN];

static const char *CVAR_ErrMsg[] = {
	"No Error",
	"Not implememented.",
	"Memory allocation failed",
	"Value overflowed while parsing",
	"Invalid numeric constant",
	"Value overflows destination type",
	"Assignment of negative value to unsigned variable",
	"Value outside of specified bounds",
	"Invalid string literal",
	"Invalid type for assignment",
	"Variable is read-only",
	"Not a valid function"
};

enum CVAR_Errors {
	CVERR_NONE,
	CVERR_NOTIMPL,
	CVERR_MEM,
	CVERR_PARSEOVERFLOW,
	CVERR_INVALID,
	CVERR_DESTOVERFLOW,
	CVERR_SIGN,
	CVERR_BOUND,
	CVERR_STRING,
	CVERR_TYPE,
	CVERR_READONLY,
	CVERR_NOTFUNC
};

static enum CVAR_Errors CVAR_ErrorState;

//Returns the appropriate cvar error string
int CVAR_GetError(const char **err_str) {
	*err_str = CVAR_ErrMsg[CVAR_ErrorState];
	return CVAR_ErrorState;
}
// Frees the cvar hash table
int CVAR_Shutdown() {
	R_CVAR *walk_ptr;
	R_CVAR *temp_ptr;
	int i;

	debug(0, "CVAR_Shutdown(): Deleting cvar hash table.");

	for (i = 0; i < R_CVAR_HASHLEN; i++) {
		for (walk_ptr = CVHashTbl[i]; walk_ptr; walk_ptr = temp_ptr) {
			temp_ptr = walk_ptr->next;
			free(walk_ptr);
		}
	}

	return R_SUCCESS;
}

// Returns hash index for string 'str'.
// Cannot fail.
unsigned int CVAR_HashString(const char *str) {
	unsigned int index;

	for (index = 0; *str != '\0'; str++) {
		index = *str + 31 * index;
	}

	return index % R_CVAR_HASHLEN;
}

// Adds a copy of the given cvar into the hash table.
// Returns R_SUCCESS if cvar was added, R_MEM if allocation failed.
int CVAR_Add(int index, R_CVAR *cvar) {
	R_CVAR *new_cvar;
	R_CVAR *temp_ptr;

	new_cvar = (R_CVAR *)malloc(sizeof(R_CVAR));

	if (new_cvar == NULL) {
		CVAR_ErrorState = CVERR_MEM;
		return R_MEM;
	}

	memcpy(new_cvar, cvar, sizeof(R_CVAR));

	if (CVHashTbl[index] == NULL) {
		CVHashTbl[index] = new_cvar;
		new_cvar->next = NULL;
	} else {
		temp_ptr = CVHashTbl[index];
		CVHashTbl[index] = new_cvar;
		new_cvar->next = temp_ptr;
	}

	CVAR_ErrorState = CVERR_NONE;
	return R_SUCCESS;
}

// Attempts to execute the specified console function with the given argument
// string.
// Returns R_FAILURE if cvar_func is not a valid console function
int CVAR_Exec(R_CVAR_P cvar_func, char *r_value) {
	int cf_argc = 0;
	char **cf_argv = NULL;
	int max_args;

	if (cvar_func->type != R_CVAR_FUNC) {
		CVAR_ErrorState = CVERR_NOTFUNC;
		return R_FAILURE;
	}

	cf_argc = EXPR_GetArgs(r_value, &cf_argv);

	if (cf_argc < cvar_func->t.func.min_args) {
		CON_Print("Too few arguments to function.");
		if (cf_argv)
			free(cf_argv);
		return R_FAILURE;
	}

	max_args = cvar_func->t.func.max_args;
	if ((max_args > -1) && (cf_argc > max_args)) {
		CON_Print("Too many arguments to function.");
		if (cf_argv)
			free(cf_argv);
		return R_FAILURE;
	}

	// Call function
	(cvar_func->t.func.func_p) (cf_argc, cf_argv);

	if (cf_argv)
		free(cf_argv);

	return R_SUCCESS;
}

// Attempts to assign the value contained in the string 'r_value' to cvar.
// Returns R_FAILURE if there was an error parsing 'r_value'
int CVAR_SetValue(R_CVAR_P cvar, char *r_value) {
	long int int_param;
	unsigned long uint16_param;

	char *end_p;
	ptrdiff_t scan_len;
	int r_value_len;

	r_value_len = strlen(r_value);

	if (cvar->flags & R_CVAR_READONLY) {
		CVAR_ErrorState = CVERR_READONLY;
		return R_FAILURE;
	}

	switch (cvar->type) {
	case R_CVAR_INT:
		int_param = strtol(r_value, &end_p, 10);
		if ((int_param == LONG_MIN) || (int_param == LONG_MAX)) {
			CVAR_ErrorState = CVERR_PARSEOVERFLOW;
			return R_FAILURE;
		}
		scan_len = end_p - r_value;

		if (int_param == 0) {
			if (!scan_len || r_value[scan_len - 1] != '0') {
				// strtol() returned 0, but string isn't "0". Invalid.
				CVAR_ErrorState = CVERR_INVALID;
				return R_FAILURE;
			}
		}

		if (scan_len != r_value_len) {
			// Entire string wasn't converted...Invalid
			CVAR_ErrorState = CVERR_INVALID;
			return R_FAILURE;
		}

		if ((int_param < CV_INTMIN) || (int_param > CV_INTMAX)) {
			// Overflows destination type
			CVAR_ErrorState = CVERR_DESTOVERFLOW;
			return R_FAILURE;
		}

		// Ignore bounds if equal
		if (cvar->t.i.lbound != cvar->t.i.ubound) {
			if ((int_param < cvar->t.i.lbound) || (int_param > cvar->t.i.ubound)) {
				// Value is outside of cvar bounds 
				CVAR_ErrorState = CVERR_BOUND;
				return R_FAILURE;
			}
		}

		*(cvar->t.i.var_p) = (cv_int_t) int_param;

#ifdef R_CVAR_TRACE
		printf("Set cvar to value %ld.\n", int_param);
#endif

		break;
	case R_CVAR_UINT:
		if (*r_value == '-') {
			CVAR_ErrorState = CVERR_SIGN;
			return R_FAILURE;
		}

		uint16_param = strtoul(r_value, &end_p, 10);
		if (uint16_param == ULONG_MAX) {
			CVAR_ErrorState = CVERR_PARSEOVERFLOW;
			return R_FAILURE;
		}

		scan_len = end_p - r_value;
		if (uint16_param == 0) {
			if (!scan_len || r_value[scan_len - 1] != '0') {
				// strtol() returned 0, but string isn't "0". Invalid.
				CVAR_ErrorState = CVERR_INVALID;
				return R_FAILURE;
			}
		}

		if (scan_len != r_value_len) {
			// Entire string wasn't converted...Invalid 
			CVAR_ErrorState = CVERR_INVALID;
			return R_FAILURE;
		}

		if (uint16_param > CV_UINTMAX) {
			// Overflows destination type 
			CVAR_ErrorState = CVERR_DESTOVERFLOW;
			return R_FAILURE;
		}

		// Ignore bounds if equal
		if (cvar->t.ui.lbound != cvar->t.ui.ubound) {
			if ((uint16_param < cvar->t.ui.lbound) || (uint16_param > cvar->t.ui.ubound)) {
				// Value is outside cvar bounds 
				CVAR_ErrorState = CVERR_BOUND;
				return R_FAILURE;
			}
		}

		*(cvar->t.ui.var_p) = (cv_uint16_t) uint16_param;
#ifdef R_CVAR_TRACE
		printf("Set cvar to value %lu.\n", uint16_param);
#endif
		break;
	case R_CVAR_FLOAT:
		CVAR_ErrorState = CVERR_NOTIMPL;
		return R_FAILURE;
		break;
	case R_CVAR_STRING:
		if (strrchr(r_value, '\"') != NULL) {
			CVAR_ErrorState = CVERR_STRING;
			return R_FAILURE;
		}
		strncpy(cvar->t.s.var_str, r_value, cvar->t.s.ubound);
		if (cvar->t.s.ubound < r_value_len) {
			cvar->t.s.var_str[cvar->t.s.ubound] = 0;
		}
#ifdef R_CVAR_TRACE
		printf("Set cvar to value \"%s\".\n", cvar->t.s.var_str);
#endif
		break;
	default:
		CVAR_ErrorState = CVERR_TYPE;
		return R_FAILURE;
		break;
	}
	CVAR_ErrorState = CVERR_NONE;
	return R_SUCCESS;
}

// Given a cvar name this function returns a pointer to the appropriate 
// cvar structure or NULL if no match was found.
R_CVAR_P CVAR_Find(const char *var_str) {
	R_CVAR *walk_ptr;
	int hash;

	hash = CVAR_HashString(var_str);
#ifdef R_CVAR_TRACE
	printf("Performing lookup on hash bucket %d.\n", hash);
#endif
	walk_ptr = CVHashTbl[hash];
	while (walk_ptr != NULL) {
		if (strcmp(var_str, walk_ptr->name) == 0) {
			return walk_ptr;
		}
		walk_ptr = walk_ptr->next;
	}

	return NULL;
}

int CVAR_IsFunc(R_CVAR_P cvar_func) {
	if (cvar_func->type == R_CVAR_FUNC)
		return 1;
	else
		return 0;
}

// Registers a console function 'cvar' 
// (could think of a better place to put these...?)
int CVAR_RegisterFunc(cv_func_t func, const char *func_name,
					 const char *func_argstr, uint16 flags, int min_args, int max_args) {
	R_CVAR new_cvar;
	int hash;

	new_cvar.name = func_name;
	new_cvar.type = R_CVAR_FUNC;
	new_cvar.section = NULL;
	new_cvar.flags = flags;
	new_cvar.t.func.func_p = func;
	new_cvar.t.func.func_argstr = func_argstr;
	new_cvar.t.func.min_args = min_args;
	new_cvar.t.func.max_args = max_args;
	hash = CVAR_HashString(func_name);

#ifdef R_CVAR_TRACE
	printf("Added FUNC cvar to hash bucket %d.\n", hash);
#endif

	return CVAR_Add(hash, &new_cvar);
}

// Registers an integer type cvar.
int CVAR_Register_I(cv_int_t * var_p, const char *var_name,
					const char *section, uint16 flags, cv_int_t lbound, cv_int_t ubound) {

	R_CVAR new_cvar;
	int hash;

	new_cvar.name = var_name;
	new_cvar.type = R_CVAR_INT;
	new_cvar.section = section;
	new_cvar.flags = flags;
	new_cvar.t.i.var_p = var_p;
	new_cvar.t.i.lbound = lbound;
	new_cvar.t.i.ubound = ubound;
	hash = CVAR_HashString(var_name);

#ifdef R_CVAR_TRACE
	printf("Added INT cvar to hash bucket %d.\n", hash);
#endif

	return CVAR_Add(hash, &new_cvar);
}

// Registers an unsigned integer type cvar.
int CVAR_Register_UI(cv_uint16_t * var_p, const char *var_name,
					const char *section, uint16 flags, cv_uint16_t lbound, cv_uint16_t ubound) {
	R_CVAR new_cvar;
	int hash;

	new_cvar.name = var_name;
	new_cvar.type = R_CVAR_UINT;
	new_cvar.section = section;
	new_cvar.flags = flags;
	new_cvar.t.ui.var_p = var_p;
	new_cvar.t.ui.lbound = lbound;
	new_cvar.t.ui.ubound = ubound;
	hash = CVAR_HashString(var_name);

#ifdef R_CVAR_TRACE
	printf("Added UNSIGNED INT ccvar to hash bucket %d.\n", hash);
#endif

	return CVAR_Add(hash, &new_cvar);
}

// Registers a floating point type cvar.
int CVAR_Register_F(cv_float_t * var_p, const char *var_name,
					const char *section, uint16 flags, cv_float_t lbound, cv_float_t ubound) {
	R_CVAR new_cvar;
	int hash;

	new_cvar.name = var_name;
	new_cvar.type = R_CVAR_FLOAT;
	new_cvar.section = section;
	new_cvar.flags = flags;
	new_cvar.t.f.var_p = var_p;
	new_cvar.t.f.lbound = lbound;
	new_cvar.t.f.ubound = ubound;
	hash = CVAR_HashString(var_name);

#ifdef R_CVAR_TRACE
	printf("Added FLOAT cvar to hash bucket %d.\n", hash);
#endif

	return CVAR_Add(hash, &new_cvar);
}

// Registers a string type cvar. Storage must be provided in var_p for 'ubound'
// characters plus 1 for NUL char. 
int CVAR_Register_S(cv_char_t * var_str, const char *var_name, const char *section, uint16 flags, int ubound) {
	R_CVAR new_cvar;
	int hash;

	new_cvar.name = var_name;
	new_cvar.type = R_CVAR_STRING;
	new_cvar.section = section;
	new_cvar.flags = flags;
	new_cvar.t.s.var_str = var_str;
	new_cvar.t.s.ubound = ubound;
	hash = CVAR_HashString(var_name);

#ifdef R_CVAR_TRACE
	printf("Added UNSIGNED INT var to hash bucket %d.\n", hash);
#endif

	return CVAR_Add(hash, &new_cvar);
}

// Displays the value and type of the given cvar to the console.
int CVAR_Print(R_CVAR_P con_cvar) {
	switch (con_cvar->type) {

	case R_CVAR_INT:
		CON_Print("\"%s\"(i) = %d", con_cvar->name, *(con_cvar->t.i.var_p));
		break;

	case R_CVAR_UINT:
		CON_Print("\"%s\"(ui) = %u", con_cvar->name, *(con_cvar->t.ui.var_p));
		break;

	case R_CVAR_FLOAT:
		CON_Print("\"%s\"(ui) = %f", con_cvar->name, *(con_cvar->t.f.var_p));
		break;

	case R_CVAR_STRING:
		CON_Print("\"%s\"(s) = \"%s\"", con_cvar->name, con_cvar->t.s.var_str);
		break;

	case R_CVAR_FUNC:
		if (con_cvar->t.func.func_argstr) {
			CON_Print("\"%s\"(func) Args: %s", con_cvar->name, con_cvar->t.func.func_argstr);
		} else {
			CON_Print("\"%s\"(func) No arguments.", con_cvar->name);
		}
		break;

	default:
		CON_Print("Invalid variable type.\n");
		break;
	}

	return R_SUCCESS;
}

} // End of namespace Saga