/*
  Copyright 2011 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 <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;
	SerdReadState* read_state;
	SordNode*      graph_uri_node;
	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;

	return serd_read_state_set_base_uri(state->read_state, uri_node);
}

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

	return serd_read_state_set_prefix(state->read_state, name, uri_node);
}

static inline SordNode*
sord_node_from_serd_node(ReadState* state, const SerdNode* sn,
                         const SerdNode* datatype, const SerdNode* lang)
{
	SordNode* datatype_node = NULL;
	SordNode* ret           = NULL;
	switch (sn->type) {
	case SERD_NOTHING:
		return NULL;
	case SERD_LITERAL:
		datatype_node = sord_node_from_serd_node(state, datatype, NULL, NULL),
		ret = sord_new_literal(
			state->world,
			datatype_node,
			sn->buf,
			sord_intern_lang(state->world, (const char*)lang->buf));
		sord_node_free(state->world, datatype_node);
		return ret;
	case SERD_URI: {
		SerdURI base_uri;
		serd_read_state_get_base_uri(state->read_state, &base_uri);
		SerdURI  abs_uri;
		SerdNode abs_uri_node = serd_node_new_uri_from_node(
			sn, &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] = sord_node_copy(state->graph_uri_node);
	} else if (graph && graph->buf) {
		tup[3] = (graph && graph->buf)
			? sord_node_from_serd_node(state, graph, NULL, NULL)
			: NULL;
	}

	sord_add(state->sord, tup);
	sord_node_free(state->world, tup[0]);
	sord_node_free(state->world, tup[1]);
	sord_node_free(state->world, tup[2]);
	sord_node_free(state->world, tup[3]);

	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;
#ifdef __WIN32__
		} else if (!strncmp((const char*)uri, "file:///", 8)) {
			filename = uri + 8;
#else
		} else if (!strncmp((const char*)uri, "file://", 7)) {
			filename = uri + 7;
#endif
		} else {
			filename = uri + 5;
		}
	} else {
		filename = uri;
	}
	return filename;
}

SORD_API
bool
sord_read_file(SordModel*     model,
               const uint8_t* uri,
               SordNode*      graph,
               const uint8_t* blank_prefix)
{
	const uint8_t* const path = sord_file_uri_to_path(uri);
	if (!path) {
		fprintf(stderr, "unable to read non-file URI `%s'\n", uri);
		return false;
	}

	FILE* const fd = fopen((const char*)path, "r");
	if (!fd) {
		fprintf(stderr, "failed to open file `%s'\n", path);
		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,
                      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();

	SerdReadState* read_state = serd_read_state_new(env, base_uri_str);

	ReadState state = { NULL, env, read_state, graph,
	                    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_read_state_free(state.read_state);
	serd_env_free(env);
	free(base_uri_str);

	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();

	SerdReadState* read_state = serd_read_state_new(env, base_uri_str);

	ReadState state = { NULL, env, read_state, NULL,
	                    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_read_state_free(state.read_state);
	serd_env_free(env);
	free(base_uri_str);

	return success;
}

SORD_API
bool
sord_write_file(SordModel*     model,
                SerdEnv*       env,
                const uint8_t* uri,
                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,
                       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;
}