/* Copyright (c) 2014, Vsevolod Stakhov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *       * Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *       * Redistributions in binary form must reproduce the above copyright
 *         notice, this list of conditions and the following disclaimer in the
 *         documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "ucl.h"
#include "ucl_internal.h"
#include "ucl_chartable.h"

#ifdef HAVE_FLOAT_H
#include <float.h>
#endif
#ifdef HAVE_MATH_H
#include <math.h>
#endif

extern const struct ucl_emitter_operations ucl_standartd_emitter_ops[];

static const struct ucl_emitter_context ucl_standard_emitters[] = {
	[UCL_EMIT_JSON] = {
		.name = "json",
		.id = UCL_EMIT_JSON,
		.func = NULL,
		.ops = &ucl_standartd_emitter_ops[UCL_EMIT_JSON]},
	[UCL_EMIT_JSON_COMPACT] = {.name = "json_compact", .id = UCL_EMIT_JSON_COMPACT, .func = NULL, .ops = &ucl_standartd_emitter_ops[UCL_EMIT_JSON_COMPACT]},
	[UCL_EMIT_CONFIG] = {.name = "config", .id = UCL_EMIT_CONFIG, .func = NULL, .ops = &ucl_standartd_emitter_ops[UCL_EMIT_CONFIG]},
	[UCL_EMIT_YAML] = {.name = "yaml", .id = UCL_EMIT_YAML, .func = NULL, .ops = &ucl_standartd_emitter_ops[UCL_EMIT_YAML]},
	[UCL_EMIT_MSGPACK] = {.name = "msgpack", .id = UCL_EMIT_MSGPACK, .func = NULL, .ops = &ucl_standartd_emitter_ops[UCL_EMIT_MSGPACK]}};

static inline void
_ucl_emitter_free(void *p)
{

	free(p);
}

/**
 * Get standard emitter context for a specified emit_type
 * @param emit_type type of emitter
 * @return context or NULL if input is invalid
 */
const struct ucl_emitter_context *
ucl_emit_get_standard_context(enum ucl_emitter emit_type)
{
	if (emit_type >= UCL_EMIT_JSON && emit_type < UCL_EMIT_MAX) {
		return &ucl_standard_emitters[emit_type];
	}

	return NULL;
}

/**
 * Serialise string
 * @param str string to emit
 * @param buf target buffer
 */
void ucl_elt_string_write_json(const char *str, size_t size,
							   struct ucl_emitter_context *ctx)
{
	const char *p = str, *c = str;
	size_t len = 0;
	const struct ucl_emitter_functions *func = ctx->func;

	func->ucl_emitter_append_character('"', 1, func->ud);

	while (size) {
		if (ucl_test_character(*p, (UCL_CHARACTER_JSON_UNSAFE |
									UCL_CHARACTER_DENIED |
									UCL_CHARACTER_WHITESPACE_UNSAFE))) {
			if (len > 0) {
				func->ucl_emitter_append_len(c, len, func->ud);
			}
			switch (*p) {
			case '\n':
				func->ucl_emitter_append_len("\\n", 2, func->ud);
				break;
			case '\r':
				func->ucl_emitter_append_len("\\r", 2, func->ud);
				break;
			case '\b':
				func->ucl_emitter_append_len("\\b", 2, func->ud);
				break;
			case '\t':
				func->ucl_emitter_append_len("\\t", 2, func->ud);
				break;
			case '\f':
				func->ucl_emitter_append_len("\\f", 2, func->ud);
				break;
			case '\v':
				func->ucl_emitter_append_len("\\u000B", 6, func->ud);
				break;
			case '\\':
				func->ucl_emitter_append_len("\\\\", 2, func->ud);
				break;
			case ' ':
				func->ucl_emitter_append_character(' ', 1, func->ud);
				break;
			case '"':
				func->ucl_emitter_append_len("\\\"", 2, func->ud);
				break;
			default:
				/* Emit unicode unknown character */
				func->ucl_emitter_append_len("\\uFFFD", 6, func->ud);
				break;
			}
			len = 0;
			c = ++p;
		}
		else {
			p++;
			len++;
		}
		size--;
	}

	if (len > 0) {
		func->ucl_emitter_append_len(c, len, func->ud);
	}

	func->ucl_emitter_append_character('"', 1, func->ud);
}

void ucl_elt_string_write_squoted(const char *str, size_t size,
								  struct ucl_emitter_context *ctx)
{
	const char *p = str, *c = str;
	size_t len = 0;
	const struct ucl_emitter_functions *func = ctx->func;

	/*
	 * Check if the string contains a backslash followed by a single quote.
	 * The squoted parser treats \' as an escape sequence, but there is no
	 * way to escape a literal backslash in squoted strings (the parser's
	 * default case for \<other> preserves both characters). Fall back to
	 * double-quoted output to avoid roundtrip corruption.
	 */
	{
		const char *scan = str;
		size_t remaining = size;
		while (remaining > 1) {
			if (scan[0] == '\\' && scan[1] == '\'') {
				ucl_elt_string_write_json(str, size, ctx);
				return;
			}
			scan++;
			remaining--;
		}
	}

	func->ucl_emitter_append_character('\'', 1, func->ud);

	while (size) {
		if (*p == '\'') {
			if (len > 0) {
				func->ucl_emitter_append_len(c, len, func->ud);
			}

			len = 0;
			func->ucl_emitter_append_len("\\\'", 2, func->ud);
			c = ++p;
		}
		else {
			p++;
			len++;
		}
		size--;
	}

	if (len > 0) {
		func->ucl_emitter_append_len(c, len, func->ud);
	}

	func->ucl_emitter_append_character('\'', 1, func->ud);
}

void ucl_elt_string_write_multiline(const char *str, size_t size,
									struct ucl_emitter_context *ctx)
{
	const struct ucl_emitter_functions *func = ctx->func;

	/*
	 * If the string contains "\nEOD\n", the heredoc would be prematurely
	 * closed on re-parse.  Fall back to JSON-style escaping in that case.
	 */
	if (size >= 4) {
		const char *found = str;
		const char *send = str + size - 4;
		while (found <= send) {
			found = memchr(found, '\n', send - found + 1);
			if (found == NULL) {
				break;
			}
			if (memcmp(found + 1, "EOD", 3) == 0 &&
				(found + 4 >= str + size || found[4] == '\n')) {
				ucl_elt_string_write_json(str, size, ctx);
				return;
			}
			found++;
		}
	}

	func->ucl_emitter_append_len("<<EOD\n", sizeof("<<EOD\n") - 1, func->ud);
	func->ucl_emitter_append_len(str, size, func->ud);
	func->ucl_emitter_append_len("\nEOD", sizeof("\nEOD") - 1, func->ud);
}

/*
 * Generic utstring output
 */
static int
ucl_utstring_append_character(unsigned char c, size_t len, void *ud)
{
	UT_string *buf = ud;

	if (len == 1) {
		utstring_append_c(buf, c);
	}
	else {
		utstring_reserve(buf, len + 1);
		memset(&buf->d[buf->i], c, len);
		buf->i += len;
		buf->d[buf->i] = '\0';
	}

	return 0;
}

static int
ucl_utstring_append_len(const unsigned char *str, size_t len, void *ud)
{
	UT_string *buf = ud;

	utstring_append_len(buf, str, len);

	return 0;
}

static int
ucl_utstring_append_int(int64_t val, void *ud)
{
	UT_string *buf = ud;

	utstring_printf(buf, "%jd", (intmax_t) val);
	return 0;
}

static int
ucl_utstring_append_double(double val, void *ud)
{
	UT_string *buf = ud;
	const double delta = 0.0000001;

	if (val == (double) (int) val) {
		utstring_printf(buf, "%.1lf", val);
	}
	else if (fabs(val - (double) (int) val) < delta) {
		/* Write at maximum precision */
		utstring_printf(buf, "%.*lg", DBL_DIG, val);
	}
	else {
		utstring_printf(buf, "%lf", val);
	}

	return 0;
}

/*
 * Generic file output
 */
static int
ucl_file_append_character(unsigned char c, size_t len, void *ud)
{
	FILE *fp = ud;

	while (len--) {
		fputc(c, fp);
	}

	return 0;
}

static int
ucl_file_append_len(const unsigned char *str, size_t len, void *ud)
{
	FILE *fp = ud;

	fwrite(str, len, 1, fp);

	return 0;
}

static int
ucl_file_append_int(int64_t val, void *ud)
{
	FILE *fp = ud;

	fprintf(fp, "%jd", (intmax_t) val);

	return 0;
}

static int
ucl_file_append_double(double val, void *ud)
{
	FILE *fp = ud;
	const double delta = 0.0000001;

	if (val == (double) (int) val) {
		fprintf(fp, "%.1lf", val);
	}
	else if (fabs(val - (double) (int) val) < delta) {
		/* Write at maximum precision */
		fprintf(fp, "%.*lg", DBL_DIG, val);
	}
	else {
		fprintf(fp, "%lf", val);
	}

	return 0;
}

/*
 * Generic file descriptor writing functions
 */
static int
ucl_fd_append_character(unsigned char c, size_t len, void *ud)
{
	int fd = *(int *) ud;
	unsigned char *buf;

	if (len == 1) {
		return write(fd, &c, 1);
	}
	else {
		buf = malloc(len);
		if (buf == NULL) {
			/* Fallback */
			while (len--) {
				if (write(fd, &c, 1) == -1) {
					return -1;
				}
			}
		}
		else {
			memset(buf, c, len);
			if (write(fd, buf, len) == -1) {
				free(buf);
				return -1;
			}
			free(buf);
		}
	}

	return 0;
}

static int
ucl_fd_append_len(const unsigned char *str, size_t len, void *ud)
{
	int fd = *(int *) ud;

	return write(fd, str, len);
}

static int
ucl_fd_append_int(int64_t val, void *ud)
{
	int fd = *(int *) ud;
	char intbuf[64];

	snprintf(intbuf, sizeof(intbuf), "%jd", (intmax_t) val);
	return write(fd, intbuf, strlen(intbuf));
}

static int
ucl_fd_append_double(double val, void *ud)
{
	int fd = *(int *) ud;
	const double delta = 0.0000001;
	char nbuf[64];

	if (val == (double) (int) val) {
		snprintf(nbuf, sizeof(nbuf), "%.1lf", val);
	}
	else if (fabs(val - (double) (int) val) < delta) {
		/* Write at maximum precision */
		snprintf(nbuf, sizeof(nbuf), "%.*lg", DBL_DIG, val);
	}
	else {
		snprintf(nbuf, sizeof(nbuf), "%lf", val);
	}

	return write(fd, nbuf, strlen(nbuf));
}

struct ucl_emitter_functions *
ucl_object_emit_memory_funcs(void **pmem)
{
	struct ucl_emitter_functions *f;
	UT_string *s;

	f = calloc(1, sizeof(*f));

	if (f != NULL) {
		f->ucl_emitter_append_character = ucl_utstring_append_character;
		f->ucl_emitter_append_double = ucl_utstring_append_double;
		f->ucl_emitter_append_int = ucl_utstring_append_int;
		f->ucl_emitter_append_len = ucl_utstring_append_len;
		f->ucl_emitter_free_func = _ucl_emitter_free;
		utstring_new(s);
		f->ud = s;
		*pmem = s->d;
		s->pd = pmem;
	}

	return f;
}

struct ucl_emitter_functions *
ucl_object_emit_file_funcs(FILE *fp)
{
	struct ucl_emitter_functions *f;

	f = calloc(1, sizeof(*f));

	if (f != NULL) {
		f->ucl_emitter_append_character = ucl_file_append_character;
		f->ucl_emitter_append_double = ucl_file_append_double;
		f->ucl_emitter_append_int = ucl_file_append_int;
		f->ucl_emitter_append_len = ucl_file_append_len;
		f->ucl_emitter_free_func = NULL;
		f->ud = fp;
	}

	return f;
}

struct ucl_emitter_functions *
ucl_object_emit_fd_funcs(int fd)
{
	struct ucl_emitter_functions *f;
	int *ip;

	f = calloc(1, sizeof(*f));

	if (f != NULL) {
		ip = malloc(sizeof(fd));
		if (ip == NULL) {
			free(f);
			return NULL;
		}

		memcpy(ip, &fd, sizeof(fd));
		f->ucl_emitter_append_character = ucl_fd_append_character;
		f->ucl_emitter_append_double = ucl_fd_append_double;
		f->ucl_emitter_append_int = ucl_fd_append_int;
		f->ucl_emitter_append_len = ucl_fd_append_len;
		f->ucl_emitter_free_func = _ucl_emitter_free;
		f->ud = ip;
	}

	return f;
}

void ucl_object_emit_funcs_free(struct ucl_emitter_functions *f)
{
	if (f != NULL) {
		if (f->ucl_emitter_free_func != NULL) {
			f->ucl_emitter_free_func(f->ud);
		}
		free(f);
	}
}


unsigned char *
ucl_object_emit_single_json(const ucl_object_t *obj)
{
	UT_string *buf = NULL;
	unsigned char *res = NULL;

	if (obj == NULL) {
		return NULL;
	}

	utstring_new(buf);

	if (buf != NULL) {
		switch (obj->type) {
		case UCL_OBJECT:
			ucl_utstring_append_len("object", 6, buf);
			break;
		case UCL_ARRAY:
			ucl_utstring_append_len("array", 5, buf);
			break;
		case UCL_INT:
			ucl_utstring_append_int(obj->value.iv, buf);
			break;
		case UCL_FLOAT:
		case UCL_TIME:
			ucl_utstring_append_double(obj->value.dv, buf);
			break;
		case UCL_NULL:
			ucl_utstring_append_len("null", 4, buf);
			break;
		case UCL_BOOLEAN:
			if (obj->value.iv) {
				ucl_utstring_append_len("true", 4, buf);
			}
			else {
				ucl_utstring_append_len("false", 5, buf);
			}
			break;
		case UCL_STRING:
			ucl_utstring_append_len(obj->value.sv, obj->len, buf);
			break;
		case UCL_USERDATA:
			ucl_utstring_append_len("userdata", 8, buf);
			break;
		}
		res = utstring_body(buf);
		free(buf);
	}

	return res;
}

#define LONG_STRING_LIMIT 80

bool ucl_maybe_long_string(const ucl_object_t *obj)
{
	if (obj->len > LONG_STRING_LIMIT || (obj->flags & UCL_OBJECT_MULTILINE)) {
		/* String is long enough, so search for newline characters in it */
		if (memchr(obj->value.sv, '\n', obj->len) != NULL) {
			return true;
		}
	}

	return false;
}