class Matrix

# Matrix provides the matrix/Matrix standard library API.
class Matrix
  # Matrix.cols stores instance state.
  # @type Nil
  cols: nil

  # Matrix.data stores instance state.
  # @type Array
  data: []

  # Matrix.rows stores instance state.
  # @type Array
  rows: []

  # Matrix.initialize provides the matrix/Matrix standard library operation.
  # @param data Array data value.
  # @return Self the initialized object.
  initialize: data = nil ->
    if data == nil
      data = [[0]]
    cols = self.validate_data(data)
    self.rows = data.len()
    self.cols = cols
    self.data = data

  # Matrix.add provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  add: a, b = nil ->
    if b == nil
      b = a
      a = self
    if a.rows != b.rows or a.cols != b.cols
      raise error("matrix.add: dimension mismatch")
    out_data = []
    i = 0
    while i < a.rows
      row = []
      j = 0
      while j < a.cols
        row.push(a.data[i][j] + b.data[i][j])
        j = j + 1
      out_data.push(row)
      i = i + 1
    Matrix(out_data)

  # Matrix.at provides the matrix/Matrix standard library operation.
  # @param m Any m value.
  # @param r Int r value.
  # @param c Any c value.
  # @return Any the resulting value.
  at: m, r, c = nil ->
    if c == nil
      c = r
      r = m
      m = self
    if r < 0 or r >= m.rows or c < 0 or c >= m.cols
      raise error("matrix.at: index out of range")
    m.data[r][c]

  # Matrix.det provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @return Any the resulting value.
  det: a = nil ->
    if a == nil
      a = self
    if a.rows != a.cols
      raise error("matrix.det: not square")
    n = a.rows
    if n > 4
      raise error("matrix.det: size > 4 not supported in v0.24")
    d = a.data
    if n == 1
      return d[0][0]
    if n == 2
      return d[0][0] * d[1][1] - d[0][1] * d[1][0]
    if n == 3
      return d[0][0] * (d[1][1] * d[2][2] - d[1][2] * d[2][1]) - d[0][1] * (d[1][0] * d[2][2] - d[1][2] * d[2][0]) + d[0][2] * (d[1][0] * d[2][1] - d[1][1] * d[2][0])
    sum = 0
    j = 0
    while j < 4
      minor_data = []
      r = 1
      while r < 4
        row = []
        c = 0
        while c < 4
          if c != j
            row.push(d[r][c])
          c = c + 1
        minor_data.push(row)
        r = r + 1
      sub_m = Matrix(minor_data)
      cofactor = self.det(sub_m) * d[0][j]
      if j % 2 == 0
        sum = sum + cofactor
      else
        sum = sum - cofactor
      j = j + 1
    sum

  # Matrix.equal? provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Boolean whether the condition is true.
  equal?: a, b = nil ->
    if b == nil
      b = a
      a = self
    if a.rows != b.rows or a.cols != b.cols
      return false
    equal(a.data, b.data)

  # Matrix.identity provides the matrix/Matrix standard library operation.
  # @param n Int n value.
  # @return Any the resulting value.
  identity: n ->
    data = []
    i = 0
    while i < n
      row = []
      j = 0
      while j < n
        if i == j
          row.push(1)
        else
          row.push(0)
        j = j + 1
      data.push(row)
      i = i + 1
    Matrix(data)

  # Matrix.mul provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  mul: a, b = nil ->
    if b == nil
      b = a
      a = self
    if a.cols != b.rows
      raise error("matrix.mul: inner dimensions disagree")
    out_data = []
    i = 0
    while i < a.rows
      row = []
      j = 0
      while j < b.cols
        sum = 0
        k = 0
        while k < a.cols
          sum = sum + a.data[i][k] * b.data[k][j]
          k = k + 1
        row.push(sum)
        j = j + 1
      out_data.push(row)
      i = i + 1
    Matrix(out_data)

  # Matrix.new provides the matrix/Matrix standard library operation.
  # @param data Array data value.
  # @return Self the resulting value.
  new: data ->
    Matrix(data)

  # Matrix.put provides the matrix/Matrix standard library operation.
  # @param m Any m value.
  # @param r Int r value.
  # @param c Any c value.
  # @param value String value value.
  # @return Any the resulting value.
  put: m, r, c, value = nil ->
    if value == nil
      value = c
      c = r
      r = m
      m = self
    if r < 0 or r >= m.rows or c < 0 or c >= m.cols
      raise error("matrix.put: index out of range")
    m.data[r][c] = value
    nil

  # Matrix.scale provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @param k Any k value.
  # @return Any the resulting value.
  scale: a, k = nil ->
    if k == nil
      k = a
      a = self
    out_data = []
    i = 0
    while i < a.rows
      row = []
      j = 0
      while j < a.cols
        row.push(a.data[i][j] * k)
        j = j + 1
      out_data.push(row)
      i = i + 1
    Matrix(out_data)

  # Matrix.sub provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @param b Int b value.
  # @return Any the resulting value.
  sub: a, b = nil ->
    if b == nil
      b = a
      a = self
    if a.rows != b.rows or a.cols != b.cols
      raise error("matrix.sub: dimension mismatch")
    out_data = []
    i = 0
    while i < a.rows
      row = []
      j = 0
      while j < a.cols
        row.push(a.data[i][j] - b.data[i][j])
        j = j + 1
      out_data.push(row)
      i = i + 1
    Matrix(out_data)

  # Matrix.transpose provides the matrix/Matrix standard library operation.
  # @param a Int a value.
  # @return Any the resulting value.
  transpose: a = nil ->
    if a == nil
      a = self
    out_data = []
    j = 0
    while j < a.cols
      row = []
      i = 0
      while i < a.rows
        row.push(a.data[i][j])
        i = i + 1
      out_data.push(row)
      j = j + 1
    Matrix(out_data)

  # Matrix.validate_data provides the matrix/Matrix standard library operation.
  # @param data Array data value.
  # @return Boolean the resulting value.
  validate_data: data ->
    if data.class != Array
      raise error("matrix.new: data must be an array of arrays")
    rows = data.len()
    if rows == 0
      raise error("matrix.new: empty matrix")
    if data[0].class != Array
      raise error("matrix.new: rows must be arrays")
    cols = data[0].len()
    i = 0
    while i < rows
      if data[i].class != Array or data[i].len() != cols
        raise error("matrix.new: inconsistent row lengths")
      j = 0
      while j < cols
        if data[i][j].class != Number
          raise error("matrix.new: elements must be numbers")
        j = j + 1
      i = i + 1
    cols

  # Matrix.zero provides the matrix/Matrix standard library operation.
  # @param rows Array rows value.
  # @param cols Any cols value.
  # @return Any the resulting value.
  zero: rows, cols ->
    data = []
    i = 0
    while i < rows
      row = []
      j = 0
      while j < cols
        row.push(0)
        j = j + 1
      data.push(row)
      i = i + 1
    Matrix(data)