module BannerFont

# File lib/banner_font.rb, line 131
def align_rows(rows, width)
  rows.map { |row| TextAlign.pad(row, width, fill: FILL) }
end

# File lib/banner_font.rb, line 47
def decode_irc_row(row, width: nil)
  w = width || glyph_row_width([row])
  top = []
  bottom = []
  normalize_glyph_row(row, w).each_char do |char|
    case char
    when FILL then top << 0; bottom << 0
    when CHAR_UPPER then top << 1; bottom << 0
    when CHAR_LOWER then top << 0; bottom << 1
    when CHAR_FULL then top << 1; bottom << 1
    else
      raise ArgumentError, "Glyph rows may only use █▀▄. and spaces."
    end
  end
  [top, bottom]
end

# File lib/banner_font.rb, line 87
def empty_ascender_row(width = WIDTH)
  Array.new(width, 0)
end

# File lib/banner_font.rb, line 36
def encode_irc_row(top, bottom)
  top.zip(bottom).map do |t, b|
    case [t.to_i, b.to_i]
    when [0, 0] then FILL
    when [1, 0] then CHAR_UPPER
    when [0, 1] then CHAR_LOWER
    when [1, 1] then CHAR_FULL
    end
  end.join
end

# File lib/banner_font.rb, line 99
def ensure_height(rows, width: nil)
  w = width || glyph_row_width(rows)
  list = Array(rows).map { |row| normalize_glyph_row(row, w) }
  return expand_cap_glyph(list, width: w) if list.length == CAP_HEIGHT
  raise ArgumentError, "Glyph needs exactly #{HEIGHT} rows." unless list.length == HEIGHT

  list
end

# File lib/banner_font.rb, line 91
def expand_cap_glyph(rows, width: nil)
  w = width || glyph_row_width(rows)
  cap_rows = Array(rows).first(CAP_HEIGHT).map { |row| normalize_glyph_row(row, w) }
  pixels = glyph_to_pixels(cap_rows, width: w)
  pixels.unshift(empty_ascender_row(w), empty_ascender_row(w).dup)
  pixels_to_glyph(pixels, width: w)
end

# File lib/banner_font.rb, line 114
def expected_line_width(text, glyphs: GLYPHS)
  chars = text.to_s.upcase.chars
  return 0 if chars.empty?

  total = chars.sum do |char|
    glyph = glyphs[char] || glyphs[" "] || GLYPHS[char] || GLYPHS[" "]
    glyph_width(glyph)
  end
  total + (chars.length - 1) * GAP.length
end

# File lib/banner_font.rb, line 125
def expected_width(char_count)
  return 0 if char_count.to_i <= 0

  char_count * (WIDTH + GAP.length) - GAP.length
end

# File lib/banner_font.rb, line 32
def glyph_row_width(rows)
  glyph_width(rows)
end

# File lib/banner_font.rb, line 64
def glyph_to_pixels(rows, width: nil)
  pixels = []
  w = width || glyph_row_width(rows)
  Array(rows).each do |row|
    top, bottom = decode_irc_row(row, width: w)
    pixels << top
    pixels << bottom
  end
  pixels
end

# File lib/banner_font.rb, line 28
def glyph_width(glyph)
  Array(glyph).map(&:length).max.to_i
end

# File lib/banner_font.rb, line 24
def normalize_glyph_row(row, width = WIDTH)
  TextAlign.pad(row.to_s.tr(" ", FILL), width, fill: FILL)[0, width]
end

# File lib/banner_font.rb, line 75
def pixels_to_glyph(grid, width: nil)
  raise ArgumentError, "expected #{PIXEL_ROWS} pixel rows" unless grid.length == PIXEL_ROWS

  w = width || (grid.first&.length || WIDTH)
  [
    encode_irc_row(grid[0], grid[1]),
    encode_irc_row(grid[2], grid[3]),
    encode_irc_row(grid[4], grid[5]),
    encode_irc_row(grid[6], grid[7])
  ].map { |row| normalize_glyph_row(row, w) }
end

# File lib/banner_font.rb, line 135
def render(text, glyphs: GLYPHS)
  chars = text.to_s.upcase.chars
  return Array.new(HEIGHT, "") if chars.empty?

  rows = Array.new(HEIGHT) { +"" }
  chars.each_with_index do |char, index|
    glyph = glyphs[char] || glyphs[" "] || GLYPHS[char] || GLYPHS[" "]
    w = glyph_width(glyph)
    glyph.each_with_index do |row, row_index|
      rows[row_index] << row[0, w]
      rows[row_index] << GAP unless index == chars.length - 1
    end
  end
  align_rows(rows, expected_line_width(text, glyphs: glyphs))
end