/*
 * (C) Copyright 2014 Leo C. <erbl259-lmu@yahoo.de>
 *
 * SPDX-License-Identifier:	GPL-2.0
 */

#include "common.h"
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <avr/eeprom.h>

#include "config.h"
#include "debug.h"
#include "xmalloc.h"
#include "crc.h"
#include "getopt-min.h"
#include "command.h"
#include "env.h"


#define ENV_SIZE	(CONFIG_ENV_SIZE - sizeof(uint16_t) -1)
#define ACTIVE_FLAG	1
#define OBSOLETE_FLAG	0

#define ENVLIST_DELETE	(1<<0)


/*
 * Default Environment
 */

#define DELIM 		"\0"

const FLASH char default_env[] = {
	ENV_BAUDRATE	  "=" "115200" DELIM
	ENV_BOOTDELAY	  "=" "3" DELIM
	ENV_BOOTCMD		  "=" "pin ${pins}; loadcpm3; go ${startaddress}" DELIM
	ENV_CPM3_SYSFILE  "=" CONFIG_CPM3_SYSFILE DELIM
	ENV_PINALIAS	  "=" "0:PG5,1:PG4,2:PB4,3:PB5,4:PB6,5:PB7,"
						  "6:PG3,7:PG2,8:PG1,9:PG0,10:PE7" DELIM
	ENV_STARTADDRESS  "=" "0" DELIM
	"pins"			  "=" "2,8 low 9 high 3 2" DELIM
	DELIM
};


/* EEPROM storage */
typedef struct environment_s {
	uint16_t	crc;		/* CRC16 over data bytes	*/
	uint8_t		flags;		/* active/obsolete flags	*/
	char		data[ENV_SIZE]; /* Environment data		*/
} env_t;


/* */
typedef struct env_item_s {
	char * envvar;
} env_item_t;


static uint8_t env_valid;
static env_item_t env_list[CONFIG_ENVVAR_MAX];
static int entrycount;


static
char env_get_char(uint16_t index)
{
	unsigned int off = CONFIG_ENV_OFFSET;
	char ret;

	switch (env_valid) {
	case 2:
		off += CONFIG_ENV_SIZE;
	case 1:
		ret = (char) eeprom_read_byte((const uint8_t *)off + index +
				offsetof(env_t, data));
		break;

	default:
		ret = default_env[index];
	}

	return ret;
}


static const FLASH char *comp_key;

static
int comp_env_items(const void *m1, const void *m2)
{
	env_item_t *ep1 = (env_item_t *) m1;
	env_item_t *ep2 = (env_item_t *) m2;

	if (ep1 == NULL)
		return - strcmp_P(ep2->envvar, comp_key);
	else
		return strcmp(ep1->envvar, ep2->envvar);
}


env_item_t *envlist_search(const MEMX char *name)
{
#ifdef __MEMX
	if (__builtin_avr_flash_segment(name) != -1) {
		comp_key = name;
		return bsearch(0, env_list, entrycount,
				sizeof(env_item_t), comp_env_items);
	} else {

		env_item_t e;
		e.envvar = (char *) name;

		return bsearch(&e, env_list, entrycount,
				sizeof(env_item_t), comp_env_items);
	}
#else
	env_item_t e;
	e.envvar = (char *) name;

	return bsearch(&e, env_list, entrycount,
				sizeof(env_item_t), comp_env_items);
#endif /* __MEMX */
}


static
env_item_t *envlist_enter(env_item_t *e)
{
	const size_t size = sizeof(env_item_t);
	env_item_t *ep;

	ep = bsearch(e, env_list, entrycount,
			size, comp_env_items);

	if (ep == NULL) {
		if (entrycount < CONFIG_ENVVAR_MAX) {

			env_list[entrycount++] = *e;
			qsort(env_list, entrycount, size, comp_env_items);
			ep = bsearch(e, env_list, entrycount,
						size, comp_env_items);
		}
	} else {
		free(ep->envvar);
		ep->envvar = e->envvar;
	}

	return ep;
}


static
int env_item_delete(env_item_t *ep)
{
	if (entrycount == 0)
		return -1;

	free(ep->envvar);

	entrycount--;
	size_t size = sizeof(env_item_t);
	memmove(ep, ep + 1, (env_list - ep)*size + entrycount*size);

	return 0;
}

static
int envlist_delete(const MEMX char *name)
{
	env_item_t *ep = envlist_search(name);

	if (ep != NULL)
		return env_item_delete(ep);

	return 1;
}



static
int envlist_import(uint8_t flags)
{
	uint16_t index;

	int len;
	env_item_t e;
	char *np, c;
	uint_fast8_t ef;

	if ((flags & ENVLIST_DELETE) != 0)
		while (entrycount != 0)
			env_item_delete(&env_list[entrycount-1]);

	for (index = 0; env_get_char(index) != '\0'; ) {
		for (len = 0; env_get_char(index + len) != '\0'; ++len) {
			if ((index + len) >= ENV_SIZE)
				return -1;
		}

		np = (char *) xmalloc(len+1);
		if (np == NULL) {
			printf_P(PSTR("## Can't malloc %d bytes\n"), len+1);
			return 1;
		}
		e.envvar = np;
		ef = 0;
		while ((c = env_get_char(index++)) != '\0') {
			if (!ef && (c == '=')) {
				*np = '\0';
				ef = 1;
			} else
				*np = c;
			np++;
		}
		*np = '\0';
		envlist_enter(&e);
	}


	return 0;
}


static
uint16_t env_crc(uint16_t data_offset)
{
	uint16_t crc;
	uint16_t i;
	char c, c0;

	crc = 0xffff;
	c = 0xff;
	for (i = 0; !(c == 0 && c0 == 0) && i < ENV_SIZE; i++)
	{
		c0 = c;
		c = eeprom_read_byte((const uint8_t *) data_offset + i);
		crc = crc16(crc, c);
	}
	return crc ;
}


/**
 * return valid env
 */
static
int env_check_valid(void)
{
	const uint16_t offset[2] = {CONFIG_ENV_OFFSET,
				    CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE};
	uint_fast8_t flags[2], crc_ok[2];
	int rc;

	/* read FLAGS */
	flags[0] = eeprom_read_byte ((uint8_t *) offset[0] +
				offsetof(env_t, flags));
	flags[1] = eeprom_read_byte ((uint8_t *) offset[1] +
				offsetof(env_t, flags));

	/* check CRC */
	crc_ok[0] = (
		eeprom_read_word((uint16_t *) offset[0] +
				offsetof(env_t, crc))
		== env_crc(offset[0] + offsetof(env_t, data))
	);
	crc_ok[1] = (
		eeprom_read_word((uint16_t *) offset[1] +
				offsetof(env_t, crc))
		== env_crc(offset[1] + offsetof(env_t, data))
	);

	if (!crc_ok[0] && !crc_ok[1]) {
		rc = 0;

	} else if (crc_ok[0] && !crc_ok[1]) {
		rc = 1;
	} else if (!crc_ok[0] && crc_ok[1]) {
		rc = 2;
	} else {
		/* both ok - check serial */
#if 1
		if      (flags[1] == ACTIVE_FLAG && flags[0] != ACTIVE_FLAG)
			rc = 2;
		else if (flags[1] == OBSOLETE_FLAG && flags[0] == 0xFF)
			rc = 2;
		else
			rc = 1;
#else
		if (flags[0] == ACTIVE_FLAG && flags[1] == OBSOLETE_FLAG)
			rc = 1;
		else if (flags[0] == OBSOLETE_FLAG && flags[1] == ACTIVE_FLAG)
			rc = 2;
		else if (flags[0] == 0xFF && flags[1] == 0)
			rc = 2;
		else if (flags[1] == 0xFF && flags[0] == 0)
			rc = 1;
		else /* flags are equal - almost impossible */
			rc = 1;
#endif
	}

	return rc;
}


int env_init(void)
{
	env_valid = env_check_valid();
	if (env_valid == 0) {
		printf_P(PSTR("*** Warning - bad CRC, "
				"using default environment\n\n"));
	}

	envlist_import(ENVLIST_DELETE);
	return 0;
}


char *getenv_str(const MEMX char *name)
{
	env_item_t *ep;
	char *ret = NULL;

	ep = envlist_search(name);
	if (ep != NULL)
		ret = ep->envvar + strlen(ep->envvar) +1;
	return ret;
}

static
int env_item_save(env_item_t *ep, uint16_t offset, int space_left)
{
	int nlen, vlen;
	char *var = ep->envvar;

	nlen = strlen(var);
	if (nlen == 0)
		return 0;
	vlen = strlen(var + nlen + 1);
	if (vlen == 0)
		return 0;
	if (nlen + vlen + 2 > space_left)
		return 0;

	eeprom_update_block(var, (uint8_t *) offset, nlen);
	offset += nlen;
	eeprom_update_byte((uint8_t *) offset++, '=');
	eeprom_update_block(var + nlen +1, (uint8_t *) offset, vlen+1);

	return nlen + vlen + 2;
}


static
int saveenv(void)
{
	unsigned int off     = CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE;
	unsigned int off_red = CONFIG_ENV_OFFSET;
	unsigned int pos;
	int len, left;
	uint16_t crc;
	int rc = 0;

	if (env_valid == 2) {
		off	= CONFIG_ENV_OFFSET;
		off_red	= CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE;
	}

	eeprom_update_byte((uint8_t *) off + offsetof(env_t, flags), 0xff);

	pos = off + offsetof(env_t, data);
	left = ENV_SIZE - 1;
	for (int i = 0 ; i < entrycount; i++) {
		len = env_item_save(&env_list[i], pos, left);
		if (len == 0) {
			return 1;
		}
		pos += len;
		left -= len;
	}
	/* terminate list */
	eeprom_update_byte((uint8_t *) pos, 0);
	crc = env_crc(off + offsetof(env_t, data));
	eeprom_update_word((uint16_t *) off + offsetof(env_t, crc), crc);
	eeprom_update_byte((uint8_t *) off + offsetof(env_t, flags),
					ACTIVE_FLAG);

	if (rc == 0) {
		eeprom_update_byte((uint8_t *) off_red + offsetof(env_t, flags),
					OBSOLETE_FLAG);
		env_valid = (env_valid == 2) ? 1 : 2;
	}

	return rc;
}


static
int env_item_print(env_item_t *ep, bool mode)
{
	int len;
	char *ev = ep->envvar;

	if (mode) {
		len = printf_P(PSTR("setenv %s "), ev) - 7;
		len += printf_P(PSTR("'%s'\n"), ev + len) - 2;
	} else {
	len = printf_P(PSTR("%s="), ev);
	len += printf_P(PSTR("%s\n"), ev + len);
	}
	return len;
}


/*
 * Command interface: print one or all environment variables
 *
 * Returns -1 in case of error, or length of printed string
 */
static
int env_print(const MEMX char *name, bool mode)
{
	int len = -1;

	if (name) {		/* print a single name */

		env_item_t *ep = envlist_search(name);
		if (ep != NULL)
			len = env_item_print(ep, mode);

	} else {		/* print whole list */
		len = 0;
		for (int i = 0 ; i < entrycount; i++) {
			len += env_item_print(&env_list[i], mode);
		}
	}
	return len;
}


/**
 * Set or delete environment variable
 *
 * Set a new environment variable,
 * or replace or delete an existing one.
 *
 * @param flag		(not used)
 * @param argc
 * @param argv[1]	Environment variable to set or delete
 *			if no more args
 * @param argv[2] ...	Value to set it to
 *
 * @return 0 if ok, 1 on error
 */
static
command_ret_t _do_env_set(int flag, int argc, char * const argv[])
{
	int i, len;
	char *name, *value, *valp, *p;
	env_item_t e, *ep;

	(void) flag;

	name = argv[1];
	value = argv[2];

	if (strchr(name, '=')) {
		printf_P(PSTR("## Error: illegal character '='"
		       "in variable name \"%s\"\n"), name);
		return CMD_RET_FAILURE;
	}
	len = strlen(name);
	if (len > CONFIG_SYS_ENV_NAMELEN) {
		printf_P(PSTR("## Error: Variable name \"%s\" too long. "
		       "(max %d characters)\n"), name, CONFIG_SYS_ENV_NAMELEN);
		return CMD_RET_FAILURE;
	}
/*
	env_id++;
*/
	/* Delete only ? */
	if (argc < 3 || argv[2] == NULL) {
		int rc = envlist_delete(name);
		return rc ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
	}

	/*
	 * Insert / replace new value
	 */
	for (i = 2, len += 1; i < argc; ++i)
		len += strlen(argv[i]) + 1;

	value = xmalloc(len);
	if (value == NULL) {
		printf_P(PSTR("## Can't malloc %d bytes\n"), len);
		return CMD_RET_FAILURE;
	}
	strcpy(value, name);
	valp = value + strlen(name) + 1;
	for (i = 2, p = valp; i < argc; ++i) {
		char *v = argv[i];

		while ((*p++ = *v++) != '\0')
			;
		*(p - 1) = ' ';
	}
	if (p != valp)
		*--p = '\0';

	e.envvar = value;
	ep = envlist_enter(&e);
	if (!ep) {
		printf_P(PSTR("## Error inserting \"%s\" variable.\n"),
			name);
		return CMD_RET_FAILURE;
	}

	return CMD_RET_SUCCESS;
}

/**
 * Set an environment variable
 *
 * @param varname	Environment variable to set
 * @param varvalue	Value to set it to
 * @return 0 if ok, 1 on error
 */
static
int setenv(const MEMX char *varname, const char *varvalue)
{
	int rc;

#ifdef __MEMX
	char *tmpname = NULL;
	if (__builtin_avr_flash_segment(varname) != -1) {
		tmpname = malloc(strlen_P(varname)+1);
		if (tmpname == NULL) {
			printf_P(PSTR("setenv: Out of Memory!\n"));
			return 1;
		}
		strcpy_P(tmpname, varname);
	} else
		tmpname = (char *) varname;
#endif

	const char * const argv[3] = { NULL, tmpname, varvalue };
	int argc = 3;

	if (varvalue == NULL || varvalue[0] == '\0')
		--argc;

	rc = (int) _do_env_set(0, argc, (char * const *)argv);

#ifdef __MEMX
	free(tmpname);
#endif
	return rc;
}

/**
 * Set an environment variable to an integer value
 *
 * @param name	Environment variable to set
 * @param value	Value to set it to
 * @param radix	Base
 * @return 0 if ok, 1 on error
 */
static
int setenv_intval(const MEMX char *name, unsigned long value, int radix)
{
	char buf[11];

	ultoa(value, buf, radix);

	return setenv(name, buf);
}

/**
 * Set an environment variable to a decimal integer value
 *
 * @param name	Environment variable to set
 * @param value	Value to set it to
 * @return 0 if ok, 1 on error
 */
int setenv_ulong(const MEMX char *name, unsigned long value)
{
	return setenv_intval(name, value, 10);
}


/**
 * Set an environment variable to a value in hex
 *
 * @param name	Environment variable to set
 * @param value	Value to set it to
 * @return 0 if ok, 1 on error
 */
int setenv_hex(const MEMX char *name, unsigned long value)
{
	return setenv_intval(name, value, 16);
}


/**
 * Decode the integer value of an environment variable and return it.
 *
 * @param name		Name of environemnt variable
 * @param base		Number base to use (normally 10, or 16 for hex)
 * @param default_val	Default value to return if the variable is not
 *			found
 * @return the decoded value, or default_val if not found
 */
unsigned long getenv_ulong(const MEMX char *name, int base, unsigned long default_val)
{
	unsigned long value;
	char *vp, *endp;

	env_item_t *ep = envlist_search(name);

	if (ep != NULL ) {
		vp = ep->envvar + strlen(ep->envvar) +1;
		value = strtoul(vp, &endp, base);
		if (endp != vp)
			return value;
	}

	return default_val;
}


/*
 * Read an environment variable as a boolean
 */
bool getenv_yesno(const MEMX char *name)
{
	char *s = getenv_str(name);

	if (s == NULL)
		return false;

	return strchr_P(PSTR("1yYtT"), *s) != NULL;

/*
	return *s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T' ?
		1 : 0;
*/
}

command_ret_t do_env_print(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	(void) cmdtp; (void) flag;

	bool mode = 0;
	command_ret_t rc = CMD_RET_SUCCESS;

	/* reset getopt() */
	optind = 0;

	int opt;
	while ((opt = getopt(argc, argv, PSTR("s"))) != -1) {
		switch (opt) {
		case 's':
			mode = 1;
			break;
		default: /* '?' */
			return CMD_RET_USAGE;
		}
	}

	if (optind == argc) {
		/* print all env vars */
		int size = env_print(NULL, mode);
		if (size < 0)
			return CMD_RET_FAILURE;
		if (mode == 0)
			printf_P(PSTR("\nEnvironment size: %d/%d bytes\n"),
				size, ENV_SIZE);
		return CMD_RET_SUCCESS;
	}

	/* print selected env vars */
	while (optind < argc) {
		int rc = env_print(argv[optind], mode);
		if (rc < 0) {
			printf_P(PSTR("## Error: \"%s\" not defined\n"), argv[optind]);
			rc = CMD_RET_FAILURE;
		}
		optind++;
	}

	return rc;
}


command_ret_t do_env_set(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	(void) cmdtp;

	if (argc < 2)
		return CMD_RET_USAGE;

	return _do_env_set(flag, argc, argv);
}


command_ret_t do_env_default(cmd_tbl_t *cmdtp, int flag,
			  int argc, char * const argv[])
{
	(void) cmdtp; (void) flag; (void) argc;	(void) argv;

	uint8_t tmp = env_valid;
	env_valid = 0;

	/* Reset the whole environment */
	printf_P(PSTR("## Resetting to default environment\n"));
	envlist_import(ENVLIST_DELETE);

	env_valid = tmp;

	return CMD_RET_SUCCESS;
}


command_ret_t do_env_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	(void) cmdtp; (void) flag; (void) argc;	(void) argv;

	printf_P(PSTR("Saving Environment ...\n"));
	return saveenv() ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
}


#if defined(CONFIG_AUTO_COMPLETE)
int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
{
	ENTRY *match;
	int found, idx;

	idx = 0;
	found = 0;
	cmdv[0] = NULL;

	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
		int vallen = strlen(match->key) + 1;

		if (found >= maxv - 2 || bufsz < vallen)
			break;

		cmdv[found++] = buf;
		memcpy(buf, match->key, vallen);
		buf += vallen;
		bufsz -= vallen;
	}

	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);

	if (idx)
		cmdv[found++] = "...";

	cmdv[found] = NULL;
	return found;
}
#endif