#!/bin/bash
set -e
# --- CONFIG ---
TOP_BAR=36
DECOR_H=30
DECOR_W=5

MASTER_RATIO_NUM=1
MASTER_RATIO_DEN=2

OUTER_GAP=8
INNER_GAP=8

# Master selection:
# focused = currently focused window
# first   = first window on desktop
# last    = last window on desktop
MASTER_MODE="focused"

# ----------------

# Get current screen resolution
read SCREEN_W SCREEN_H <<< $(xrandr | awk '
/\*/ {
    split($1,a,"x")
    print a[1], a[2]
    exit
}')

USABLE_H=$((SCREEN_H - TOP_BAR))

# Work area after outer gaps
WORK_X=$OUTER_GAP
WORK_Y=$((TOP_BAR + OUTER_GAP))
WORK_W=$((SCREEN_W - 2 * OUTER_GAP))
WORK_H=$((USABLE_H - 2 * OUTER_GAP))

# --- focused window ---
FOCUSED=$(printf "0x%08x" "$(xdotool getactivewindow)")

# --- current desktop ---
CUR_DESKTOP=$(xdotool get_desktop)

# --- collect windows on current desktop ---
ALL_WINDOWS=$(wmctrl -l -x | awk '$2!="-1" {print $1}')

WINDOWS=()

for w in $ALL_WINDOWS; do
    win_desktop=$(xdotool get_desktop_for_window "$(printf "%d" "$w")" 2>/dev/null) || continue

    if [ "$win_desktop" = "$CUR_DESKTOP" ]; then
        WINDOWS+=("$w")
    fi
done

if [ ${#WINDOWS[@]} -eq 0 ]; then
    echo "No windows found on current desktop."
    exit 1
fi

# ----------------------------------------------------
# Determine master window
# ----------------------------------------------------

case "$MASTER_MODE" in
    focused)
        MASTER="$FOCUSED"
        ;;
    first)
        MASTER="${WINDOWS[0]}"
        ;;
    last)
        MASTER="${WINDOWS[$((${#WINDOWS[@]} - 1))]}"
        ;;
    *)
        echo "Invalid MASTER_MODE: $MASTER_MODE"
        exit 1
        ;;
esac

# --- separate master from stack ---
STACK=()

for w in "${WINDOWS[@]}"; do
    if [ "$w" != "$MASTER" ]; then
        STACK+=("$w")
    fi
done

place() {
    local id=$1
    local x=$2
    local y=$3
    local raw_w=$4
    local raw_h=$5
    local class decor_h decor_w x_offset y_offset
    x_offset=0
    y_offset=0

    class=$(xprop -id "$id" WM_CLASS 2>/dev/null | sed -r 's/.*"(.*)"$/\1/')
    case "$class" in
        Alacritty)
            decor_h=42
            decor_w=8
            ;;
        Chromium)
            decor_h=42
            decor_w=5
            ;;
        obsidian)
            decor_h=5
            decor_w=0
            x_offset=-0
            y_offset=-0
            ;;
        dev.zed.Zed)
            decor_h=-19
            decor_w=-23
            x_offset=-13
            y_offset=-13
            ;;
        *)
            decor_h=$DECOR_H
            decor_w=$DECOR_W
            ;;
    esac

    local w=$((raw_w - decor_w))
    local h=$((raw_h - decor_h))
    local fx=$((x + x_offset))
    local fy=$((y + y_offset))
    wmctrl -i -r "$id" -b remove,maximized_vert,maximized_horz
    wmctrl -i -r "$id" -e 1,"$fx","$fy","$w","$h"
}

# ----------------------------------------------------
# Single window
# ----------------------------------------------------

if [ ${#WINDOWS[@]} -eq 1 ]; then
    place \
        "$MASTER" \
        "$WORK_X" \
        "$WORK_Y" \
        "$WORK_W" \
        "$WORK_H"

    exit 0
fi

# ----------------------------------------------------
# Master / Stack layout
# ----------------------------------------------------

MID=$((WORK_W * MASTER_RATIO_NUM / MASTER_RATIO_DEN))

MASTER_X=$WORK_X
MASTER_Y=$WORK_Y

MASTER_W=$((MID - INNER_GAP / 2))
MASTER_H=$WORK_H

STACK_X=$((WORK_X + MID + INNER_GAP / 2))
STACK_Y=$WORK_Y

STACK_W=$((WORK_W - MID - INNER_GAP / 2))
STACK_H=$WORK_H

# --- place master ---
place \
    "$MASTER" \
    "$MASTER_X" \
    "$MASTER_Y" \
    "$MASTER_W" \
    "$MASTER_H"

# --- place stack ---
COUNT=${#STACK[@]}

if [ "$COUNT" -gt 0 ]; then

    SLOT_H=$(((STACK_H - INNER_GAP * (COUNT - 1)) / COUNT))

    i=0

    for w in "${STACK[@]}"; do

        SLOT_Y=$((STACK_Y + i * (SLOT_H + INNER_GAP)))

        place \
            "$w" \
            "$STACK_X" \
            "$SLOT_Y" \
            "$STACK_W" \
            "$SLOT_H"

        i=$((i + 1))
    done
fi