/*
 * Copyright (c) 2009-2020, Peter Abeles. All Rights Reserved.
 *
 * This file is part of Efficient Java Matrix Library (EJML).
 *
 * 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.
 */

package org.ejml.ops;

import org.ejml.data.*;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * Reads in a matrix that is in a column-space-value (CSV) format.
 *
 * @author Peter Abeles
 */
@SuppressWarnings("unchecked")
public class ReadMatrixCsv extends ReadCsv {

    /**
     * Specifies where input comes from.
     *
     * @param in Where the input comes from.
     */
    public ReadMatrixCsv( InputStream in ) {
        super(in);
    }

    /**
     * Reads in a {@link Matrix} from the IO stream.
     *
     * @return Matrix
     * @throws IOException If anything goes wrong.
     */
    public <M extends Matrix> M read32() throws IOException {
        List<String> words = extractWords();
        if (words == null)
            throw new IllegalArgumentException("Not enough lines in file");
        if (words.size() == 3) {
            int numRows = Integer.parseInt(words.get(0));
            int numCols = Integer.parseInt(words.get(1));
            boolean real = words.get(2).compareToIgnoreCase("real") == 0;

            if (numRows < 0 || numCols < 0)
                throw new IOException("Invalid number of rows and/or columns: " + numRows + " " + numCols);

            if (real)
                return (M)readFDRM(numRows, numCols);
            else
                return (M)readCDRM(numRows, numCols);
        } else if (words.size() == 4) {
            int numRows = Integer.parseInt(words.get(0));
            int numCols = Integer.parseInt(words.get(1));
            int length = Integer.parseInt(words.get(2));
            boolean real = words.get(3).compareToIgnoreCase("real") == 0;

            if (numRows < 0 || numCols < 0)
                throw new IOException("Invalid number of rows and/or columns: " + numRows + " " + numCols);

            if (real)
                return (M)readFSTR(numRows, numCols, length);
            else
                throw new IllegalArgumentException("Sparse complex not yet supported");
        } else {
            throw new IOException("Unexpected number of words on the first line. Found " + words.size());
        }
    }

    /**
     * Reads in a {@link Matrix} from the IO stream.
     *
     * @return Matrix
     * @throws IOException If anything goes wrong.
     */
    public <M extends Matrix> M read64() throws IOException {
        List<String> words = extractWords();
        if (words == null)
            throw new IllegalArgumentException("Not enough lines in file");
        if (words.size() == 3) {
            int numRows = Integer.parseInt(words.get(0));
            int numCols = Integer.parseInt(words.get(1));
            boolean real = words.get(2).compareToIgnoreCase("real") == 0;

            if (numRows < 0 || numCols < 0)
                throw new IOException("Invalid number of rows and/or columns: " + numRows + " " + numCols);

            if (real)
                return (M)readDDRM(numRows, numCols);
            else
                return (M)readZDRM(numRows, numCols);
        } else if (words.size() == 4) {
            int numRows = Integer.parseInt(words.get(0));
            int numCols = Integer.parseInt(words.get(1));
            int length = Integer.parseInt(words.get(2));
            boolean real = words.get(3).compareToIgnoreCase("real") == 0;

            if (numRows < 0 || numCols < 0)
                throw new IOException("Invalid number of rows and/or columns: " + numRows + " " + numCols);

            if (real)
                return (M)readDSTR(numRows, numCols, length);
            else
                throw new IllegalArgumentException("Sparse complex not yet supported");
        } else {
            throw new IOException("Unexpected number of words on the first line. Found " + words.size());
        }
    }

    /**
     * Reads in a {@link DMatrixRMaj} from the IO stream where the user specifies the matrix dimensions.
     *
     * @param numRows Number of rows in the matrix
     * @param numCols Number of columns in the matrix
     * @return DMatrixRMaj
     */
    public DMatrixRMaj readDDRM( int numRows, int numCols ) throws IOException {

        DMatrixRMaj A = new DMatrixRMaj(numRows, numCols);

        for (int i = 0; i < numRows; i++) {
            List<String> words = extractWords();
            if (words == null)
                throw new IOException("Too few rows found. expected " + numRows + " actual " + i);

            if (words.size() != numCols)
                throw new IOException("Unexpected number of words in column. Found " + words.size() + " expected " + numCols);
            for (int j = 0; j < numCols; j++) {
                A.set(i, j, Double.parseDouble(words.get(j)));
            }
        }

        return A;
    }

    /**
     * Reads in a {@link FMatrixRMaj} from the IO stream where the user specifies the matrix dimensions.
     *
     * @param numRows Number of rows in the matrix
     * @param numCols Number of columns in the matrix
     * @return FMatrixRMaj
     */
    public FMatrixRMaj readFDRM( int numRows, int numCols ) throws IOException {

        FMatrixRMaj A = new FMatrixRMaj(numRows, numCols);

        for (int i = 0; i < numRows; i++) {
            List<String> words = extractWords();
            if (words == null)
                throw new IOException("Too few rows found. expected " + numRows + " actual " + i);

            if (words.size() != numCols)
                throw new IOException("Unexpected number of words in column. Found " + words.size() + " expected " + numCols);
            for (int j = 0; j < numCols; j++) {
                A.set(i, j, Float.parseFloat(words.get(j)));
            }
        }

        return A;
    }

    /**
     * Reads in a {@link ZMatrixRMaj} from the IO stream where the user specifies the matrix dimensions.
     *
     * @param numRows Number of rows in the matrix
     * @param numCols Number of columns in the matrix
     * @return ZMatrixRMaj
     */
    public ZMatrixRMaj readZDRM( int numRows, int numCols ) throws IOException {

        ZMatrixRMaj A = new ZMatrixRMaj(numRows, numCols);

        int wordsCol = numCols*2;

        for (int i = 0; i < numRows; i++) {
            List<String> words = extractWords();
            if (words == null)
                throw new IOException("Too few rows found. expected " + numRows + " actual " + i);

            if (words.size() != wordsCol)
                throw new IOException("Unexpected number of words in column. Found " + words.size() + " expected " + wordsCol);
            for (int j = 0; j < wordsCol; j += 2) {

                double real = Double.parseDouble(words.get(j));
                double imaginary = Double.parseDouble(words.get(j + 1));

                A.set(i, j/2, real, imaginary);
            }
        }

        return A;
    }

    /**
     * Reads in a {@link CMatrixRMaj} from the IO stream where the user specifies the matrix dimensions.
     *
     * @param numRows Number of rows in the matrix
     * @param numCols Number of columns in the matrix
     * @return CMatrixRMaj
     */
    public CMatrixRMaj readCDRM( int numRows, int numCols ) throws IOException {

        CMatrixRMaj A = new CMatrixRMaj(numRows, numCols);

        int wordsCol = numCols*2;

        for (int i = 0; i < numRows; i++) {
            List<String> words = extractWords();
            if (words == null)
                throw new IOException("Too few rows found. expected " + numRows + " actual " + i);

            if (words.size() != wordsCol)
                throw new IOException("Unexpected number of words in column. Found " + words.size() + " expected " + wordsCol);
            for (int j = 0; j < wordsCol; j += 2) {

                float real = Float.parseFloat(words.get(j));
                float imaginary = Float.parseFloat(words.get(j + 1));

                A.set(i, j/2, real, imaginary);
            }
        }

        return A;
    }

    private FMatrixSparseTriplet readFSTR( int numRows, int numCols, int length ) throws IOException {
        List<String> words;
        FMatrixSparseTriplet m = new FMatrixSparseTriplet(numRows, numCols, length);

        for (int i = 0; i < length; i++) {
            words = extractWords();
            if (words == null)
                throw new IllegalArgumentException("Not enough lines in file");
            if (words.size() != 3)
                throw new IllegalArgumentException("Unexpected number of words on line " + getLineNumber());

            int row = Integer.parseInt(words.get(0));
            int col = Integer.parseInt(words.get(1));
            float value = Float.parseFloat(words.get(2));

            m.addItem(row, col, value);
        }

        return m;
    }

    private DMatrixSparseTriplet readDSTR( int numRows, int numCols, int length ) throws IOException {
        List<String> words;
        DMatrixSparseTriplet m = new DMatrixSparseTriplet(numRows, numCols, length);

        for (int i = 0; i < length; i++) {
            words = extractWords();
            if (words == null)
                throw new IllegalArgumentException("Not enough lines in file");
            if (words.size() != 3)
                throw new IllegalArgumentException("Unexpected number of words on line " + getLineNumber());

            int row = Integer.parseInt(words.get(0));
            int col = Integer.parseInt(words.get(1));
            double value = Double.parseDouble(words.get(2));

            m.addItem(row, col, value);
        }

        return m;
    }
}
