/*
  Copyright (c) 2019 Sogou, Inc.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

	  http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  Author: Xie Han (xiehan@sogou-inc.com;63350856@qq.com)
*/

#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <vector>
#include "workflow/WFTaskFactory.h"
#include "workflow/WFFacilities.h"

namespace algorithm
{

typedef std::vector<std::vector<double>> Matrix;

struct MMInput
{
	Matrix a;
	Matrix b;
};

struct MMOutput
{
	int error;
	size_t m, n, k;
	Matrix c;
};

bool is_valid_matrix(const Matrix& matrix, size_t& m, size_t& n)
{
	m = n = 0;
	if (matrix.size() == 0)
		return true;

	m = matrix.size();
	n = matrix[0].size();
	if (n == 0)
		return false;

	for (const auto& row : matrix)
		if (row.size() != n)
			return false;

	return true;
}

void matrix_multiply(const MMInput *in, MMOutput *out)
{
	size_t m1, n1;
	size_t m2, n2;

	if (!is_valid_matrix(in->a, m1, n1) || !is_valid_matrix(in->b, m2, n2))
	{
		out->error = EINVAL;
		return;
	}

	if (n1 != m2)
	{
		out->error = EINVAL;
		return;
	}

	out->error = 0;
	out->m = m1;
	out->n = n2;
	out->k = n1;

	out->c.resize(m1);
	for (size_t i = 0; i < out->m; i++)
	{
		out->c[i].resize(n2);
		for (size_t j = 0; j < out->n; j++)
		{
			out->c[i][j] = 0;
			for (size_t k = 0; k < out->k; k++)
				out->c[i][j] += in->a[i][k] * in->b[k][j];
		}
	}
}

}

using MMTask = WFThreadTask<algorithm::MMInput,
							algorithm::MMOutput>;

using namespace algorithm;

void print_matrix(const Matrix& matrix, size_t m, size_t n)
{
	for (size_t i = 0; i < m; i++)
	{
		for (size_t j = 0; j < n; j++)
			printf("\t%8.2lf", matrix[i][j]);

		printf("\n");
	}
}

void callback(MMTask *task)
{
	auto *input = task->get_input();
	auto *output = task->get_output();

	assert(task->get_state() == WFT_STATE_SUCCESS);

	if (output->error)
		printf("Error: %d %s\n", output->error, strerror(output->error));
	else
	{
		printf("Matrix A\n");
		print_matrix(input->a, output->m, output->k);
		printf("Matrix B\n");
		print_matrix(input->b, output->k, output->n);
		printf("Matrix A * Matrix B =>\n");
		print_matrix(output->c, output->m, output->n);
	}
}

int main()
{
	using MMFactory = WFThreadTaskFactory<MMInput,
										  MMOutput>;
	MMTask *task = MMFactory::create_thread_task("matrix_multiply_task",
												matrix_multiply,
												callback);
	auto *input = task->get_input();

	input->a = {{1, 2, 3}, {4, 5, 6}};
	input->b = {{7, 8}, {9, 10}, {11, 12}};

	WFFacilities::WaitGroup wait_group(1);

	Workflow::start_series_work(task, [&wait_group](const SeriesWork *) {
		wait_group.done();
	});

	wait_group.wait();
	return 0;
}