#!/bin/env bash
#
## Calculate DPI and adjust display settings if necesary

REGEX_XRANDR='^.* ([0-9]+)x([0-9]+)\+[0-9]+\+[0-9]+.* ([0-9]+)mm x ([0-9]+)mm.*$'
REGEX_URXVT='(URxvt.geometry:\s+).*'

# Get screen data
xrandr_str="$(xrandr | grep mm | head -1)"
width_px="$(echo "${xrandr_str}" | sed -r "s/${REGEX_XRANDR}/\1/")"
height_px="$(echo "${xrandr_str}" | sed -r "s/${REGEX_XRANDR}/\2/")"
width_mm="$(echo "${xrandr_str}" | sed -r "s/${REGEX_XRANDR}/\3/")"
height_mm="$(echo "${xrandr_str}" | sed -r "s/${REGEX_XRANDR}/\4/")"

# Convert to in
width_in="$(echo "${width_mm} * 0.03937" | bc)"
height_in="$(echo "${height_mm} * 0.03937" | bc)"

# Calculate diagonals
diag_px="$(echo "sqrt(${width_px}^2 + ${height_px}^2)" | bc)"
diag_in="$(echo "sqrt(${width_in}^2 + ${height_in}^2)" | bc)"

# Calculate DPI
dpi="$(echo "${diag_px} / ${diag_in}" | bc 2>/dev/null || True)"
dpi="${dpi:-0}"

# Calculate URxvt default window size
width_urxvt="$(echo "${width_px} * 112/1280" | bc)"
height_urxvt="$(echo "${height_px} * 33/720" | bc)"
offset_urxvt="24"

# Update settings if necessary
if [[ "${dpi}" -ge 192 ]]; then
  # Conky
  sed -i 's/minimum_size 180 0/minimum_size 360 0/' "${HOME}/.conkyrc"
  sed -i 's/maximum_width 180/maximum_width 360/' "${HOME}/.conkyrc"
  sed -i 's/gap_x 20/gap_x 40/' "${HOME}/.conkyrc"
  sed -i 's/gap_y 24/gap_y 48/' "${HOME}/.conkyrc"

  # Fonts
  sed -i 's/!Xft.dpi: 192/Xft.dpi: 192/' "${HOME}/.Xresources"

  # GDK
  export GDK_SCALE=2
  export GDK_DPI_SCALE=0.5

  # i3
  sed -i -r 's/(height\s+) 26/\1 52/' "${HOME}/.config/i3/config"

  # Tint2
  sed -i 's/panel_size = 100% 30/panel_size = 100% 60/' \
    "${HOME}/.config/tint2/tint2rc"
  sed -i 's/Inconsolata 10/Inconsolata 20/g' \
    "${HOME}/.config/tint2/tint2rc"
  sed -i 's/Inconsolata 12/Inconsolata 24/g' \
    "${HOME}/.config/tint2/tint2rc"
  sed -i 's/systray_icon_size = 24/systray_icon_size = 48/' \
    "${HOME}/.config/tint2/tint2rc"

  # URxvt
  width_urxvt="$(echo "${width_urxvt} / 2" | bc)"
  height_urxvt="$(echo "${height_urxvt} / 2" | bc)"
  offset_urxvt="$(echo "${offset_urxvt} * 2" | bc)"
fi

# Update URxvt (Always)
urxvt_geometry="${width_urxvt}x${height_urxvt}+${offset_urxvt}+${offset_urxvt}"
sed -i -r "s/${REGEX_URXVT}/\1${urxvt_geometry}/" "${HOME}/.Xresources"