/*
  Copyright 2011-2017 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.
*/

#include "serd_internal.h"

#include <ctype.h>
#include <errno.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int
r_err(SerdReader* reader, SerdStatus st, const char* fmt, ...)
{
	va_list args;
	va_start(args, fmt);
	const Cursor* const cur = &reader->source.cur;
	const SerdError e = { st, cur->filename, cur->line, cur->col, fmt, &args };
	serd_error(reader->error_sink, reader->error_handle, &e);
	va_end(args);
	return 0;
}

void
set_blank_id(SerdReader* reader, Ref ref, size_t buf_size)
{
	SerdNode*   node   = deref(reader, ref);
	const char* prefix = reader->bprefix ? (const char*)reader->bprefix : "";
	node->n_bytes = node->n_chars = snprintf(
		(char*)node->buf, buf_size, "%sb%u", prefix, reader->next_id++);
}

size_t
genid_size(SerdReader* reader)
{
	return reader->bprefix_len + 1 + 10 + 1;  // + "b" + UINT32_MAX + \0
}

Ref
blank_id(SerdReader* reader)
{
	Ref ref = push_node_padded(reader, genid_size(reader), SERD_BLANK, "", 0);
	set_blank_id(reader, ref, genid_size(reader));
	return ref;
}

/** fread-like wrapper for getc (which is faster). */
static size_t
serd_file_read_byte(void* buf, size_t size, size_t nmemb, void* stream)
{
	const int c = getc((FILE*)stream);
	if (c == EOF) {
		*((uint8_t*)buf) = 0;
		return 0;
	}
	*((uint8_t*)buf) = (uint8_t)c;
	return 1;
}

Ref
push_node_padded(SerdReader* reader, size_t maxlen,
                 SerdType type, const char* str, size_t n_bytes)
{
	void* mem = serd_stack_push_aligned(
		&reader->stack, sizeof(SerdNode) + maxlen + 1, sizeof(SerdNode));

	SerdNode* const node = (SerdNode*)mem;
	node->n_bytes = node->n_chars = n_bytes;
	node->flags   = 0;
	node->type    = type;
	node->buf     = NULL;

	uint8_t* buf = (uint8_t*)(node + 1);
	memcpy(buf, str, n_bytes + 1);

#ifdef SERD_STACK_CHECK
	reader->allocs = realloc(
		reader->allocs, sizeof(reader->allocs) * (++reader->n_allocs));
	reader->allocs[reader->n_allocs - 1] = ((uint8_t*)mem - reader->stack.buf);
#endif
	return (uint8_t*)node - reader->stack.buf;
}

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

SerdNode*
deref(SerdReader* reader, const Ref ref)
{
	if (ref) {
		SerdNode* node = (SerdNode*)(reader->stack.buf + ref);
		node->buf = (uint8_t*)node + sizeof(SerdNode);
		return node;
	}
	return NULL;
}

Ref
pop_node(SerdReader* reader, Ref ref)
{
	if (ref && ref != reader->rdf_first && ref != reader->rdf_rest
	    && ref != reader->rdf_nil) {
#ifdef SERD_STACK_CHECK
		SERD_STACK_ASSERT_TOP(reader, ref);
		--reader->n_allocs;
#endif
		SerdNode* const node = deref(reader, ref);
		uint8_t* const  top  = reader->stack.buf + reader->stack.size;
		serd_stack_pop_aligned(&reader->stack, top - (uint8_t*)node);
	}
	return 0;
}

bool
emit_statement(SerdReader* reader, ReadContext ctx, Ref o, Ref d, Ref l)
{
	SerdNode* graph = deref(reader, ctx.graph);
	if (!graph && reader->default_graph.buf) {
		graph = &reader->default_graph;
	}
	bool ret = !reader->statement_sink ||
		!reader->statement_sink(
			reader->handle, *ctx.flags, graph,
			deref(reader, ctx.subject), deref(reader, ctx.predicate),
			deref(reader, o), deref(reader, d), deref(reader, l));
	*ctx.flags &= SERD_ANON_CONT|SERD_LIST_CONT;  // Preserve only cont flags
	return ret;
}

static bool
read_statement(SerdReader* reader)
{
	switch (reader->syntax) {
	default: return read_n3_statement(reader);
	}
}

static bool
read_doc(SerdReader* reader)
{
	switch (reader->syntax) {
	case SERD_NQUADS: return read_nquadsDoc(reader);
	default:          return read_turtleTrigDoc(reader);
	}
}

SERD_API
SerdReader*
serd_reader_new(SerdSyntax        syntax,
                void*             handle,
                void              (*free_handle)(void*),
                SerdBaseSink      base_sink,
                SerdPrefixSink    prefix_sink,
                SerdStatementSink statement_sink,
                SerdEndSink       end_sink)
{
	SerdReader*  me  = (SerdReader*)calloc(1, sizeof(SerdReader));
	me->handle           = handle;
	me->free_handle      = free_handle;
	me->base_sink        = base_sink;
	me->prefix_sink      = prefix_sink;
	me->statement_sink   = statement_sink;
	me->end_sink         = end_sink;
	me->default_graph    = SERD_NODE_NULL;
	me->stack            = serd_stack_new(SERD_PAGE_SIZE);
	me->syntax           = syntax;
	me->next_id          = 1;
	me->strict           = true;

	me->rdf_first = push_node(me, SERD_URI, NS_RDF "first", 48);
	me->rdf_rest  = push_node(me, SERD_URI, NS_RDF "rest", 47);
	me->rdf_nil   = push_node(me, SERD_URI, NS_RDF "nil", 46);

	return me;
}

SERD_API
void
serd_reader_set_strict(SerdReader* reader, bool strict)
{
	reader->strict = strict;
}

SERD_API
void
serd_reader_set_error_sink(SerdReader*   reader,
                           SerdErrorSink error_sink,
                           void*         error_handle)
{
	reader->error_sink   = error_sink;
	reader->error_handle = error_handle;
}

SERD_API
void
serd_reader_free(SerdReader* reader)
{
	pop_node(reader, reader->rdf_nil);
	pop_node(reader, reader->rdf_rest);
	pop_node(reader, reader->rdf_first);
	serd_node_free(&reader->default_graph);

#ifdef SERD_STACK_CHECK
	free(reader->allocs);
#endif
	free(reader->stack.buf);
	free(reader->bprefix);
	if (reader->free_handle) {
		reader->free_handle(reader->handle);
	}
	free(reader);
}

SERD_API
void*
serd_reader_get_handle(const SerdReader* reader)
{
	return reader->handle;
}

SERD_API
void
serd_reader_add_blank_prefix(SerdReader*    reader,
                             const uint8_t* prefix)
{
	free(reader->bprefix);
	reader->bprefix_len = 0;
	reader->bprefix     = NULL;
	if (prefix) {
		reader->bprefix_len = strlen((const char*)prefix);
		reader->bprefix     = (uint8_t*)malloc(reader->bprefix_len + 1);
		memcpy(reader->bprefix, prefix, reader->bprefix_len + 1);
	}
}

SERD_API
void
serd_reader_set_default_graph(SerdReader*     reader,
                              const SerdNode* graph)
{
	serd_node_free(&reader->default_graph);
	reader->default_graph = serd_node_copy(graph);
}

SERD_API
SerdStatus
serd_reader_read_file(SerdReader*    reader,
                      const uint8_t* uri)
{
	uint8_t* const path = serd_file_uri_parse(uri, NULL);
	if (!path) {
		return SERD_ERR_BAD_ARG;
	}

	FILE* fd = serd_fopen((const char*)path, "rb");
	if (!fd) {
		free(path);
		return SERD_ERR_UNKNOWN;
	}

	SerdStatus ret = serd_reader_read_file_handle(reader, fd, path);
	fclose(fd);
	free(path);
	return ret;
}

static SerdStatus
skip_bom(SerdReader* me)
{
	if (serd_byte_source_peek(&me->source) == 0xEF) {
		serd_byte_source_advance(&me->source);
		if (serd_byte_source_peek(&me->source) != 0xBB ||
		    serd_byte_source_advance(&me->source) ||
		    serd_byte_source_peek(&me->source) != 0xBF ||
		    serd_byte_source_advance(&me->source)) {
			r_err(me, SERD_ERR_BAD_SYNTAX, "corrupt byte order mark\n");
			return SERD_ERR_BAD_SYNTAX;
		}
	}

	return SERD_SUCCESS;
}

SERD_API
SerdStatus
serd_reader_start_stream(SerdReader*    reader,
                         FILE*          file,
                         const uint8_t* name,
                         bool           bulk)
{
	return serd_reader_start_source_stream(
		reader,
		bulk ? (SerdSource)fread : serd_file_read_byte,
		(SerdStreamErrorFunc)ferror,
		file,
		name,
		bulk ? SERD_PAGE_SIZE : 1);
}

SERD_API
SerdStatus
serd_reader_start_source_stream(SerdReader*         reader,
                                SerdSource          read_func,
                                SerdStreamErrorFunc error_func,
                                void*               stream,
                                const uint8_t*      name,
                                size_t              page_size)
{
	return serd_byte_source_open_source(
		&reader->source, read_func, error_func, stream, name, page_size);
}

static SerdStatus
serd_reader_prepare(SerdReader* reader)
{
	reader->status = serd_byte_source_prepare(&reader->source);
	if (reader->status == SERD_SUCCESS) {
		reader->status = skip_bom(reader);
	} else if (reader->status == SERD_FAILURE) {
		reader->source.eof = true;
	} else {
		r_err(reader, reader->status, "read error: %s\n", strerror(errno));
	}
	return reader->status;
}

SERD_API
SerdStatus
serd_reader_read_chunk(SerdReader* reader)
{
	SerdStatus st = SERD_SUCCESS;
	if (!reader->source.prepared) {
		if ((st = serd_reader_prepare(reader))) {
			return st;
		}
	} else if (reader->source.eof) {
		reader->source.eof = false;
		if ((st = serd_byte_source_advance(&reader->source))) {
			return st;
		}
	}
	return read_statement(reader) ? SERD_SUCCESS : SERD_FAILURE;
}

SERD_API
SerdStatus
serd_reader_end_stream(SerdReader* reader)
{
	return serd_byte_source_close(&reader->source);
}

SERD_API
SerdStatus
serd_reader_read_file_handle(SerdReader*    reader,
                             FILE*          file,
                             const uint8_t* name)
{
	return serd_reader_read_source(
		reader, (SerdSource)fread, (SerdStreamErrorFunc)ferror,
		file, name, SERD_PAGE_SIZE);
}

SERD_API
SerdStatus
serd_reader_read_source(SerdReader*         reader,
                        SerdSource          source,
                        SerdStreamErrorFunc error,
                        void*               stream,
                        const uint8_t*      name,
                        size_t              page_size)
{
	SerdStatus st = serd_reader_start_source_stream(
		reader, source, error, stream, name, page_size);

	if (st || (st = serd_reader_prepare(reader))) {
		serd_reader_end_stream(reader);
		return st;
	} else if (!read_doc(reader)) {
		serd_reader_end_stream(reader);
		return SERD_ERR_UNKNOWN;
	}

	return serd_reader_end_stream(reader);
}

SERD_API
SerdStatus
serd_reader_read_string(SerdReader* reader, const uint8_t* utf8)
{
	serd_byte_source_open_string(&reader->source, utf8);

	SerdStatus st = serd_reader_prepare(reader);
	if (!st) {
		st = read_doc(reader) ? SERD_SUCCESS : SERD_ERR_UNKNOWN;
	}

	serd_byte_source_close(&reader->source);

	return st;
}