#!/usr/bin/env bash
set -e

# Set the system theme declaratively.
# Usage: nomarchy-theme-set <theme-name> [--no-update]

THEME_NAME="$1"
NO_UPDATE=false

if [[ "${2:-}" == "--no-update" ]]; then
  NO_UPDATE=true
fi

if [[ -z $THEME_NAME ]]; then
  echo "Usage: nomarchy-theme-set <theme-name> [--no-update]"
  exit 1
fi

STATE_DIR="$HOME/.config/nomarchy"
STATE_FILE="$STATE_DIR/state.json"

# Resolve themes directory (Built-in from Nix store via Home Manager, or user extra)
if [ -d "$HOME/.config/nomarchy/themes/$THEME_NAME" ]; then
  THEMES_DIR="$HOME/.config/nomarchy/themes"
else
  THEMES_DIR="$HOME/.local/share/nomarchy/themes"
fi

mkdir -p "$STATE_DIR"
[[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"

if [ ! -d "$THEMES_DIR/$THEME_NAME" ] && ! [[ "$THEME_NAME" == "nord" ]]; then
  echo "Theme '$THEME_NAME' not found in $THEMES_DIR"
fi

TMP_JSON=$(mktemp)
jq --arg theme "$THEME_NAME" '.theme = $theme' "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"

# Sync to system state if we have permissions (for system-level theming like browser policies)
SYSTEM_STATE_FILE="/etc/nixos/state.json"
if [ -w "$SYSTEM_STATE_FILE" ] || [ -w "/etc/nixos" ]; then
    sudo jq --arg theme "$THEME_NAME" '.theme = $theme' "$SYSTEM_STATE_FILE" > /tmp/system-state.json 2>/dev/null && sudo mv /tmp/system-state.json "$SYSTEM_STATE_FILE" 2>/dev/null || true
fi

# Try to find a background for this theme
BG_DIR="$THEMES_DIR/$THEME_NAME/backgrounds"
if [ -d "$BG_DIR" ]; then
  BG=$(ls "$BG_DIR" | head -n 1)
  if [ -n "$BG" ]; then
    TMP_JSON=$(mktemp)
    jq --arg wp "$BG_DIR/$BG" '.wallpaper = $wp' "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"
  fi
fi

echo "Theme set to $THEME_NAME. Applying changes with nomarchy-env-update..."

if [[ "$NO_UPDATE" == "true" ]]; then
  echo "Skipping nomarchy-env-update due to --no-update flag."
  exit 0
fi

nomarchy-env-update

nomarchy-theme-set-templates

# Run the chain of "tell each app the theme changed" steps. Each step is
# optional — the corresponding helper might not be installed, the service
# might not be running, the user might not use Obsidian. Skipping is fine;
# what we don't want is a step that EXISTS, fails for a real reason, and
# leaves the user with a half-applied theme + no idea why. Collect every
# real failure into _theme_set_fails and surface them in one notify-send
# at the end so the user knows exactly what didn't refresh.
_theme_set_fails=()

_theme_set_try() {
    local label="$1"; shift
    # First arg after label is the command to test for existence.
    # `systemctl` always exists on a NixOS system, so we let it through
    # and rely on its own exit code to decide skip vs fail.
    if [[ "$1" != "systemctl" ]] && ! command -v "$1" >/dev/null 2>&1; then
        return 0   # not installed → silently skip
    fi
    if ! "$@" >/dev/null 2>&1; then
        _theme_set_fails+=("$label")
    fi
}

# Walker reads its CSS via @import of ~/.config/nomarchy/current/theme/apps/walker/style.css,
# and waybar's shared fallback style does the same with waybar.css. HM's sd-switch
# only restarts services whose unit *definition* changed, so when only the imported
# file's contents change, neither gets reloaded. Restart them explicitly.
_theme_set_try "Walker"  nomarchy-restart-walker
_theme_set_try "Waybar"  nomarchy-restart-waybar

# Hot-reload long-running TUIs / agents that read their colors from
# the active-theme symlink and would otherwise stay on the old palette
# until the user restarts them by hand.
_theme_set_try "btop"     nomarchy-restart-btop
_theme_set_try "opencode" nomarchy-restart-opencode

# Sync palette into Obsidian vaults (no-op when the user has no Obsidian
# config or no obsidian.css template in the active theme).
_theme_set_try "Obsidian" nomarchy-theme-set-obsidian

# Reload the wallpaper — its ExecStart path is stable (~/.config/nomarchy/current/background)
# so sd-switch does not detect a unit change when only the symlink target moves.
_theme_set_try "wallpaper" systemctl --user restart nomarchy-wallpaper.service

if (( ${#_theme_set_fails[@]} > 0 )); then
    if command -v notify-send >/dev/null 2>&1; then
        notify-send -u normal "Theme applied with warnings" \
            "Did not refresh: $(IFS=', '; echo "${_theme_set_fails[*]}")"
    fi
    echo "Warning: failed to refresh: ${_theme_set_fails[*]}" >&2
fi

nomarchy-hook theme-set "$THEME_NAME"