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

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.

  2. 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 THE
  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.
*/

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include "serd/serd.h"

#include "sord-config.h"
#include "sord_internal.h"

typedef struct {
	SerdReader reader;
	SerdEnv    env;
	SordNode   graph_uri_node;
	SerdNode   base_uri_node;
	SerdURI    base_uri;
	SordWorld  world;
	SordModel  sord;
} ReadState;

static uint8_t*
copy_string(const uint8_t* str, size_t* n_bytes)
{
	const size_t   len = strlen((const char*)str);
	uint8_t* const ret = malloc(len + 1);
	memcpy(ret, str, len + 1);
	*n_bytes = len + 1;
	return ret;
}

static bool
event_base(void*           handle,
           const SerdNode* uri_node)
{
	ReadState* const state = (ReadState*)handle;

	// Resolve base URI and create a new node and URI for it
	SerdURI  base_uri;
	SerdNode base_uri_node = serd_node_new_uri_from_node(
		uri_node, &state->base_uri, &base_uri);

	if (base_uri_node.buf) {
		// Replace the current base URI
		serd_node_free(&state->base_uri_node);
		state->base_uri_node = base_uri_node;
		state->base_uri      = base_uri;
		return true;
	}
	return false;
}

static bool
event_prefix(void*           handle,
             const SerdNode* name,
             const SerdNode* uri_node)
{
	ReadState* const state = (ReadState*)handle;
	if (serd_uri_string_has_scheme(uri_node->buf)) {
		// Set prefix to absolute URI
		serd_env_add(state->env, name, uri_node);
	} else {
		// Resolve relative URI and create a new node and URI for it
		SerdURI  abs_uri;
		SerdNode abs_uri_node = serd_node_new_uri_from_node(
			uri_node, &state->base_uri, &abs_uri);

		if (!abs_uri_node.buf) {
			return false;
		}

		// Set prefix to resolved (absolute) URI
		serd_env_add(state->env, name, &abs_uri_node);
		serd_node_free(&abs_uri_node);
	}
	return true;
}

static inline SordNode
sord_node_from_serd_node(ReadState* state, const SerdNode* sn,
                         const SerdNode* datatype, const SerdNode* lang)
{
	switch (sn->type) {
	case SERD_NOTHING:
		return NULL;
	case SERD_LITERAL:
		return sord_new_literal(
			state->world,
			sord_node_from_serd_node(state, datatype, NULL, NULL),
			sn->buf,
			g_intern_string((const char*)lang->buf));
	case SERD_URI: {
		SerdURI  abs_uri;
		SerdNode abs_uri_node = serd_node_new_uri_from_node(
			sn, &state->base_uri, &abs_uri);
		SordNode ret = sord_new_uri(state->world, abs_uri_node.buf);
		serd_node_free(&abs_uri_node);
		return ret;
	}
	case SERD_CURIE: {
		SerdChunk uri_prefix;
		SerdChunk uri_suffix;
		if (!serd_env_expand(state->env, sn, &uri_prefix, &uri_suffix)) {
			fprintf(stderr, "ERROR: failed to expand qname `%s'\n", sn->buf);
			return NULL;
		}
		const size_t uri_len = uri_prefix.len + uri_suffix.len;
		uint8_t*     buf     = malloc(uri_len + 1);
		memcpy(buf,                  uri_prefix.buf, uri_prefix.len);
		memcpy(buf + uri_prefix.len, uri_suffix.buf, uri_suffix.len);
		buf[uri_len] = '\0';
		SordNode ret = sord_new_uri_counted(state->world,
		                                    buf, uri_prefix.len + uri_suffix.len);
		free(buf);
		return ret;
	}
	case SERD_BLANK_ID:
	case SERD_ANON_BEGIN:
	case SERD_ANON:
		return sord_new_blank(state->world, sn->buf);
	}
	return NULL;
}

static inline void
sord_node_to_serd_node(const SordNode node, SerdNode* out)
{
	if (!node) {
		*out = SERD_NODE_NULL;
		return;
	}
	switch (node->type) {
	case SORD_URI:
		out->type = SERD_URI;
		break;
	case SORD_BLANK:
		out->type = SERD_BLANK_ID;
		break;
	case SORD_LITERAL:
		out->type = SERD_LITERAL;
		break;
	}
	size_t len;
	out->buf = sord_node_get_string_counted(node, &len);
	out->n_bytes = len;
	out->n_chars = len - 1; // FIXME: UTF-8
}

static bool
event_statement(void*           handle,
                const SerdNode* graph,
                const SerdNode* subject,
                const SerdNode* predicate,
                const SerdNode* object,
                const SerdNode* object_datatype,
                const SerdNode* object_lang)
{
	ReadState* const state = (ReadState*)handle;

	SordQuad tup;
	tup[0] = sord_node_from_serd_node(state, subject, NULL, NULL);
	tup[1] = sord_node_from_serd_node(state, predicate, NULL, NULL);
	tup[2] = sord_node_from_serd_node(state, object,
	                                  object_datatype, object_lang);

	if (state->graph_uri_node) {
		assert(graph->type == SERD_NOTHING);
		tup[3] = state->graph_uri_node;
	} else {
		tup[3] = (graph && graph->buf)
			? sord_node_from_serd_node(state, graph, NULL, NULL)
			: NULL;
	}

	sord_add(state->sord, tup);

	return true;
}

static const uint8_t*
sord_file_uri_to_path(const uint8_t* uri)
{
	const uint8_t* filename = NULL;
	if (serd_uri_string_has_scheme(uri)) {
		// Absolute URI, ensure it a file and chop scheme
		if (strncmp((const char*)uri, "file:", 5)) {
			fprintf(stderr, "unsupported URI scheme `%s'\n", uri);
			return NULL;
		} else if (!strncmp((const char*)uri, "file://", 7)) {
			filename = uri + 7;
		} else {
			filename = uri + 5;
		}
	} else {
		filename = uri;
	}
	return filename;
}

SORD_API
bool
sord_read_file(SordModel      model,
               const uint8_t* uri,
               const SordNode graph,
               const uint8_t* blank_prefix)
{
	const uint8_t* const path = sord_file_uri_to_path(uri);
	if (!path) {
		return false;
	}

	FILE* const fd = fopen((const char*)path,  "r");
	if (!fd) {
		return false;
	}

	const bool ret = sord_read_file_handle(model, fd, uri, graph, blank_prefix);
	fclose(fd);
	return ret;
}

SORD_API
bool
sord_read_file_handle(SordModel      model,
                      FILE*          fd,
                      const uint8_t* base_uri_str_in,
                      const SordNode graph,
                      const uint8_t* blank_prefix)
{
	size_t   base_uri_n_bytes = 0;
	uint8_t* base_uri_str     = copy_string(base_uri_str_in, &base_uri_n_bytes);

	SerdURI  base_uri;
	if (!serd_uri_parse(base_uri_str, &base_uri)) {
		fprintf(stderr, "invalid base URI `%s'\n", base_uri_str);
	}

	SerdEnv env = serd_env_new();

	const SerdNode base_uri_node = { SERD_URI,
	                                 base_uri_n_bytes,
	                                 base_uri_n_bytes - 1,  // FIXME: UTF-8
	                                 base_uri_str };

	ReadState state = { NULL, env, graph,
	                    base_uri_node, base_uri,
	                    sord_get_world(model), model };

	state.reader = serd_reader_new(
		SERD_TURTLE, &state,
		event_base, event_prefix, event_statement, NULL);

	if (blank_prefix) {
		serd_reader_set_blank_prefix(state.reader, blank_prefix);
	}

	const bool success = serd_reader_read_file(state.reader, fd, base_uri_str);

	serd_reader_free(state.reader);
	serd_node_free(&state.base_uri_node);

	return success;
}

SORD_API
bool
sord_read_string(SordModel      model,
                 const uint8_t* str,
                 const uint8_t* base_uri_str_in)
{
	size_t   base_uri_n_bytes = 0;
	uint8_t* base_uri_str     = copy_string(base_uri_str_in, &base_uri_n_bytes);

	SerdURI  base_uri;
	if (!serd_uri_parse(base_uri_str, &base_uri)) {
		fprintf(stderr, "invalid base URI `%s'\n", base_uri_str);
	}

	SerdEnv env = serd_env_new();

	const SerdNode base_uri_node = { SERD_URI,
	                                 base_uri_n_bytes,
	                                 base_uri_n_bytes - 1,  // FIXME: UTF-8
	                                 base_uri_str };

	ReadState state = { NULL, env, NULL,
	                    base_uri_node, base_uri,
	                    sord_get_world(model), model };

	state.reader = serd_reader_new(
		SERD_TURTLE, &state,
		event_base, event_prefix, event_statement, NULL);

	const bool success = serd_reader_read_string(state.reader, str);

	serd_reader_free(state.reader);
	serd_node_free(&state.base_uri_node);

	return success;
}

SORD_API
bool
sord_write_file(SordModel      model,
                SerdEnv        env,
                const uint8_t* uri,
                const SordNode graph,
                const uint8_t* blank_prefix)
{
	const uint8_t* const path = sord_file_uri_to_path(uri);
	if (!path) {
		return false;
	}

	FILE* const fd = fopen((const char*)path,  "w");
	if (!fd) {
		fprintf(stderr, "failed to open file %s\n", path);
		return false;
	}

	const bool ret = sord_write_file_handle(model, env, fd, uri, graph, blank_prefix);
	fclose(fd);
	return ret;
}

static size_t
file_sink(const void* buf, size_t len, void* stream)
{
	FILE* file = (FILE*)stream;
	return fwrite(buf, 1, len, file);
}

static void
sord_write(const SordModel model,
           const SordNode  graph,
           SerdWriter      writer)
{
	SerdNode s_graph;
	sord_node_to_serd_node(graph, &s_graph);
	for (SordIter i = sord_begin(model); !sord_iter_end(i); sord_iter_next(i)) {
		SordQuad quad;
		sord_iter_get(i, quad);

		SerdNode subject;
		SerdNode predicate;
		SerdNode object;
		SerdNode datatype;
		sord_node_to_serd_node(quad[SORD_SUBJECT],   &subject);
		sord_node_to_serd_node(quad[SORD_PREDICATE], &predicate);
		sord_node_to_serd_node(quad[SORD_OBJECT],    &object);
		
		sord_node_to_serd_node(sord_node_get_datatype(quad[SORD_OBJECT]), &datatype);
		const char* lang_str = sord_node_get_language(quad[SORD_OBJECT]);
		size_t      lang_len = lang_str ? strlen(lang_str) : 0;
		
		SerdNode language = SERD_NODE_NULL;
		if (lang_str) {
			language.type    = SERD_LITERAL;
			language.n_bytes = lang_len + 1;
			language.n_chars = lang_len; // FIXME: UTF-8
			language.buf     = (const uint8_t*)lang_str;
		};
			    
		serd_writer_write_statement(writer, &s_graph,
		                            &subject, &predicate, &object,
		                            &datatype, &language);
	}
}


static SerdWriter
make_writer(SerdEnv        env,
            const uint8_t* base_uri_str_in,
            SerdSink       sink,
            void*          stream)
{
	size_t   base_uri_n_bytes = 0;
	uint8_t* base_uri_str     = copy_string(base_uri_str_in, &base_uri_n_bytes);
	SerdURI  base_uri;
	if (!serd_uri_parse(base_uri_str, &base_uri)) {
		fprintf(stderr, "invalid base URI `%s'\n", base_uri_str);
	}

	SerdWriter writer = serd_writer_new(SERD_TURTLE,
	                                    SERD_STYLE_ABBREVIATED|SERD_STYLE_CURIED,
	                                    env,
	                                    &base_uri,
	                                    sink,
	                                    stream);

	serd_env_foreach(env,
	                 (SerdPrefixSink)serd_writer_set_prefix,
	                 writer);

	return writer;
}

SORD_API
bool
sord_write_file_handle(SordModel      model,
                       SerdEnv        env,
                       FILE*          fd,
                       const uint8_t* base_uri_str_in,
                       const SordNode graph,
                       const uint8_t* blank_prefix)
{
	SerdWriter writer = make_writer(env, base_uri_str_in, file_sink, fd);
	sord_write(model, graph, writer);
	serd_writer_free(writer);
	return true;
}

struct SerdBuffer {
	uint8_t* buf;
	size_t   len;
};

static size_t
string_sink(const void* buf, size_t len, void* stream)
{
	struct SerdBuffer* out = (struct SerdBuffer*)stream;
	out->buf = realloc(out->buf, out->len + len);
	memcpy(out->buf + out->len, buf, len);
	out->len += len;
	return len;
}

SORD_API
uint8_t*
sord_write_string(SordModel      model,
                  SerdEnv        env,
                  const uint8_t* base_uri)
{
	struct SerdBuffer buf = { NULL, 0 };
	SerdWriter writer = make_writer(env, base_uri, string_sink, &buf);
	sord_write(model, NULL, writer);
	serd_writer_free(writer);
	string_sink("", 1, &buf);
	return buf.buf;
}