/*
  Copyright 2011-2020 David Robillard <http://drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#ifndef SERD_READER_H
#define SERD_READER_H

#include "byte_source.h"
#include "stack.h"

#include "serd/serd.h"

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

#if defined(__GNUC__)
#    define SERD_LOG_FUNC(fmt, arg1) __attribute__((format(printf, fmt, arg1)))
#else
#    define SERD_LOG_FUNC(fmt, arg1)
#endif

#ifdef SERD_STACK_CHECK
#    define SERD_STACK_ASSERT_TOP(reader, ref) \
            assert(ref == reader->allocs[reader->n_allocs - 1]);
#else
#    define SERD_STACK_ASSERT_TOP(reader, ref)
#endif

/* Reference to a node in the stack (we can not use pointers since the
   stack may be reallocated, invalidating any pointers to elements).
*/
typedef size_t Ref;

typedef struct {
	Ref                 graph;
	Ref                 subject;
	Ref                 predicate;
	Ref                 object;
	Ref                 datatype;
	Ref                 lang;
	SerdStatementFlags* flags;
} ReadContext;

struct SerdReaderImpl {
	void*             handle;
	void              (*free_handle)(void* ptr);
	SerdBaseSink      base_sink;
	SerdPrefixSink    prefix_sink;
	SerdStatementSink statement_sink;
	SerdEndSink       end_sink;
	SerdErrorSink     error_sink;
	void*             error_handle;
	Ref               rdf_first;
	Ref               rdf_rest;
	Ref               rdf_nil;
	SerdNode          default_graph;
	SerdByteSource    source;
	SerdStack         stack;
	SerdSyntax        syntax;
	unsigned          next_id;
	SerdStatus        status;
	uint8_t*          buf;
	uint8_t*          bprefix;
	size_t            bprefix_len;
	bool              strict;     ///< True iff strict parsing
	bool              seen_genid;
#ifdef SERD_STACK_CHECK
	Ref*              allocs;     ///< Stack of push offsets
	size_t            n_allocs;   ///< Number of stack pushes
#endif
};

SERD_LOG_FUNC(3, 4)
SerdStatus
r_err(SerdReader* reader, SerdStatus st, const char* fmt, ...);

Ref push_node_padded(SerdReader* reader,
                     size_t      maxlen,
                     SerdType    type,
                     const char* str,
                     size_t      n_bytes);

Ref push_node(SerdReader* reader,
              SerdType    type,
              const char* str,
              size_t      n_bytes);

size_t genid_size(SerdReader* reader);
Ref    blank_id(SerdReader* reader);
void   set_blank_id(SerdReader* reader, Ref ref, size_t buf_size);

SerdNode* deref(SerdReader* reader, Ref ref);

Ref pop_node(SerdReader* reader, Ref ref);

bool emit_statement(SerdReader* reader, ReadContext ctx, Ref o, Ref d, Ref l);

bool read_n3_statement(SerdReader* reader);
bool read_nquadsDoc(SerdReader* reader);
bool read_turtleTrigDoc(SerdReader* reader);

static inline int
peek_byte(SerdReader* reader)
{
	SerdByteSource* source = &reader->source;

	return source->eof ? EOF : (int)source->read_buf[source->read_head];
}

static inline int
eat_byte(SerdReader* reader)
{
	const int        c  = peek_byte(reader);
	const SerdStatus st = serd_byte_source_advance(&reader->source);
	if (st) {
		reader->status = st;
	}
	return c;
}

static inline int
eat_byte_safe(SerdReader* reader, const int byte)
{
	(void)byte;

	const int c = eat_byte(reader);
	assert(c == byte);
	return c;
}

static inline int
eat_byte_check(SerdReader* reader, const int byte)
{
	const int c = peek_byte(reader);
	if (c != byte) {
		r_err(reader, SERD_ERR_BAD_SYNTAX,
		      "expected `%c', not `%c'\n", byte, c);
		return 0;
	}
	return eat_byte_safe(reader, byte);
}

static inline bool
eat_string(SerdReader* reader, const char* str, unsigned n)
{
	bool bad = false;
	for (unsigned i = 0; i < n; ++i) {
		bad |= (bool)eat_byte_check(reader, ((const uint8_t*)str)[i]);
	}
	return bad;
}

static inline SerdStatus
push_byte(SerdReader* reader, Ref ref, const int c)
{
	assert(c != EOF);
	SERD_STACK_ASSERT_TOP(reader, ref);

	uint8_t* const  s    = (uint8_t*)serd_stack_push(&reader->stack, 1);
	SerdNode* const node = (SerdNode*)(reader->stack.buf + ref);
	++node->n_bytes;
	if (!(c & 0x80)) {  // Starts with 0 bit, start of new character
		++node->n_chars;
	}
	*(s - 1) = (uint8_t)c;
	*s       = '\0';
	return SERD_SUCCESS;
}

static inline void
push_bytes(SerdReader* reader, Ref ref, const uint8_t* bytes, unsigned len)
{
	for (unsigned i = 0; i < len; ++i) {
		push_byte(reader, ref, bytes[i]);
	}
}

#endif // SERD_READER_H