<?php

/**
 *
 * Class for the management of Matrices
 *
 * @copyright  Copyright (c) 2018 Mark Baker (https://github.com/MarkBaker/PHPMatrix)
 * @license    https://opensource.org/licenses/MIT    MIT
 */
namespace LWVendor\Matrix;

use Generator;
use LWVendor\Matrix\Decomposition\LU;
use LWVendor\Matrix\Decomposition\QR;
/**
 * Matrix object.
 *
 * @package Matrix
 *
 * @property-read int $rows The number of rows in the matrix
 * @property-read int $columns The number of columns in the matrix
 * @method Matrix antidiagonal()
 * @method Matrix adjoint()
 * @method Matrix cofactors()
 * @method float determinant()
 * @method Matrix diagonal()
 * @method Matrix identity()
 * @method Matrix inverse()
 * @method Matrix minors()
 * @method float trace()
 * @method Matrix transpose()
 * @method Matrix add(...$matrices)
 * @method Matrix subtract(...$matrices)
 * @method Matrix multiply(...$matrices)
 * @method Matrix divideby(...$matrices)
 * @method Matrix divideinto(...$matrices)
 * @method Matrix directsum(...$matrices)
 */
class Matrix
{
    protected $rows;
    protected $columns;
    protected $grid = [];
    /*
     * Create a new Matrix object from an array of values
     *
     * @param array $grid
     */
    public final function __construct(array $grid)
    {
        $this->buildFromArray(\array_values($grid));
    }
    /*
     * Create a new Matrix object from an array of values
     *
     * @param array $grid
     */
    protected function buildFromArray(array $grid) : void
    {
        $this->rows = \count($grid);
        $columns = \array_reduce($grid, function ($carry, $value) {
            return \max($carry, \is_array($value) ? \count($value) : 1);
        });
        $this->columns = $columns;
        \array_walk($grid, function (&$value) use($columns) {
            if (!\is_array($value)) {
                $value = [$value];
            }
            $value = \array_pad(\array_values($value), $columns, null);
        });
        $this->grid = $grid;
    }
    /**
     * Validate that a row number is a positive integer
     *
     * @param int $row
     * @return int
     * @throws Exception
     */
    public static function validateRow(int $row) : int
    {
        if (!\is_numeric($row) || \intval($row) < 1) {
            throw new Exception('Invalid Row');
        }
        return (int) $row;
    }
    /**
     * Validate that a column number is a positive integer
     *
     * @param int $column
     * @return int
     * @throws Exception
     */
    public static function validateColumn(int $column) : int
    {
        if (!\is_numeric($column) || \intval($column) < 1) {
            throw new Exception('Invalid Column');
        }
        return (int) $column;
    }
    /**
     * Validate that a row number falls within the set of rows for this matrix
     *
     * @param int $row
     * @return int
     * @throws Exception
     */
    protected function validateRowInRange(int $row) : int
    {
        $row = static::validateRow($row);
        if ($row > $this->rows) {
            throw new Exception('Requested Row exceeds matrix size');
        }
        return $row;
    }
    /**
     * Validate that a column number falls within the set of columns for this matrix
     *
     * @param int $column
     * @return int
     * @throws Exception
     */
    protected function validateColumnInRange(int $column) : int
    {
        $column = static::validateColumn($column);
        if ($column > $this->columns) {
            throw new Exception('Requested Column exceeds matrix size');
        }
        return $column;
    }
    /**
     * Return a new matrix as a subset of rows from this matrix, starting at row number $row, and $rowCount rows
     * A $rowCount value of 0 will return all rows of the matrix from $row
     * A negative $rowCount value will return rows until that many rows from the end of the matrix
     *
     * Note that row numbers start from 1, not from 0
     *
     * @param int $row
     * @param int $rowCount
     * @return static
     * @throws Exception
     */
    public function getRows(int $row, int $rowCount = 1) : Matrix
    {
        $row = $this->validateRowInRange($row);
        if ($rowCount === 0) {
            $rowCount = $this->rows - $row + 1;
        }
        return new static(\array_slice($this->grid, $row - 1, (int) $rowCount));
    }
    /**
     * Return a new matrix as a subset of columns from this matrix, starting at column number $column, and $columnCount columns
     * A $columnCount value of 0 will return all columns of the matrix from $column
     * A negative $columnCount value will return columns until that many columns from the end of the matrix
     *
     * Note that column numbers start from 1, not from 0
     *
     * @param int $column
     * @param int $columnCount
     * @return Matrix
     * @throws Exception
     */
    public function getColumns(int $column, int $columnCount = 1) : Matrix
    {
        $column = $this->validateColumnInRange($column);
        if ($columnCount < 1) {
            $columnCount = $this->columns + $columnCount - $column + 1;
        }
        $grid = [];
        for ($i = $column - 1; $i < $column + $columnCount - 1; ++$i) {
            $grid[] = \array_column($this->grid, $i);
        }
        return (new static($grid))->transpose();
    }
    /**
     * Return a new matrix as a subset of rows from this matrix, dropping rows starting at row number $row,
     *     and $rowCount rows
     * A negative $rowCount value will drop rows until that many rows from the end of the matrix
     * A $rowCount value of 0 will remove all rows of the matrix from $row
     *
     * Note that row numbers start from 1, not from 0
     *
     * @param int $row
     * @param int $rowCount
     * @return static
     * @throws Exception
     */
    public function dropRows(int $row, int $rowCount = 1) : Matrix
    {
        $this->validateRowInRange($row);
        if ($rowCount === 0) {
            $rowCount = $this->rows - $row + 1;
        }
        $grid = $this->grid;
        \array_splice($grid, $row - 1, (int) $rowCount);
        return new static($grid);
    }
    /**
     * Return a new matrix as a subset of columns from this matrix, dropping columns starting at column number $column,
     *     and $columnCount columns
     * A negative $columnCount value will drop columns until that many columns from the end of the matrix
     * A $columnCount value of 0 will remove all columns of the matrix from $column
     *
     * Note that column numbers start from 1, not from 0
     *
     * @param int $column
     * @param int $columnCount
     * @return static
     * @throws Exception
     */
    public function dropColumns(int $column, int $columnCount = 1) : Matrix
    {
        $this->validateColumnInRange($column);
        if ($columnCount < 1) {
            $columnCount = $this->columns + $columnCount - $column + 1;
        }
        $grid = $this->grid;
        \array_walk($grid, function (&$row) use($column, $columnCount) {
            \array_splice($row, $column - 1, (int) $columnCount);
        });
        return new static($grid);
    }
    /**
     * Return a value from this matrix, from the "cell" identified by the row and column numbers
     * Note that row and column numbers start from 1, not from 0
     *
     * @param int $row
     * @param int $column
     * @return mixed
     * @throws Exception
     */
    public function getValue(int $row, int $column)
    {
        $row = $this->validateRowInRange($row);
        $column = $this->validateColumnInRange($column);
        return $this->grid[$row - 1][$column - 1];
    }
    /**
     * Returns a Generator that will yield each row of the matrix in turn as a vector matrix
     *     or the value of each cell if the matrix is a column vector
     *
     * @return Generator|Matrix[]|mixed[]
     */
    public function rows() : Generator
    {
        foreach ($this->grid as $i => $row) {
            (yield $i + 1 => $this->columns == 1 ? $row[0] : new static([$row]));
        }
    }
    /**
     * Returns a Generator that will yield each column of the matrix in turn as a vector matrix
     *     or the value of each cell if the matrix is a row vector
     *
     * @return Generator|Matrix[]|mixed[]
     */
    public function columns() : Generator
    {
        for ($i = 0; $i < $this->columns; ++$i) {
            (yield $i + 1 => $this->rows == 1 ? $this->grid[0][$i] : new static(\array_column($this->grid, $i)));
        }
    }
    /**
     * Identify if the row and column dimensions of this matrix are equal,
     *     i.e. if it is a "square" matrix
     *
     * @return bool
     */
    public function isSquare() : bool
    {
        return $this->rows === $this->columns;
    }
    /**
     * Identify if this matrix is a vector
     *     i.e. if it comprises only a single row or a single column
     *
     * @return bool
     */
    public function isVector() : bool
    {
        return $this->rows === 1 || $this->columns === 1;
    }
    /**
     * Return the matrix as a 2-dimensional array
     *
     * @return array
     */
    public function toArray() : array
    {
        return $this->grid;
    }
    /**
     * Solve A*X = B.
     *
     * @param Matrix $B Right hand side
     *
     * @throws Exception
     *
     * @return Matrix ... Solution if A is square, least squares solution otherwise
     */
    public function solve(Matrix $B) : Matrix
    {
        if ($this->columns === $this->rows) {
            return (new LU($this))->solve($B);
        }
        return (new QR($this))->solve($B);
    }
    protected static $getters = ['rows', 'columns'];
    /**
     * Access specific properties as read-only (no setters)
     *
     * @param string $propertyName
     * @return mixed
     * @throws Exception
     */
    public function __get(string $propertyName)
    {
        $propertyName = \strtolower($propertyName);
        // Test for function calls
        if (\in_array($propertyName, self::$getters)) {
            return $this->{$propertyName};
        }
        throw new Exception('Property does not exist');
    }
    protected static $functions = ['adjoint', 'antidiagonal', 'cofactors', 'determinant', 'diagonal', 'identity', 'inverse', 'minors', 'trace', 'transpose'];
    protected static $operations = ['add', 'subtract', 'multiply', 'divideby', 'divideinto', 'directsum'];
    /**
     * Returns the result of the function call or operation
     *
     * @param string $functionName
     * @param mixed[] $arguments
     * @return Matrix|float
     * @throws Exception
     */
    public function __call(string $functionName, $arguments)
    {
        $functionName = \strtolower(\str_replace('_', '', $functionName));
        // Test for function calls
        if (\in_array($functionName, self::$functions, \true)) {
            return Functions::$functionName($this, ...$arguments);
        }
        // Test for operation calls
        if (\in_array($functionName, self::$operations, \true)) {
            return Operations::$functionName($this, ...$arguments);
        }
        throw new Exception('Function or Operation does not exist');
    }
}