<?php

namespace Modules\Stylist\Theme;

use Modules\Stylist\Services\TenantThemeResolver;
use Modules\Stylist\Services\ThemeSettings;
use Modules\Stylist\Theme\Exceptions\ThemeNotFoundException;

final class Stylist
{
    public function __construct(private readonly Loader $loader, private readonly TenantThemeResolver $resolver, private readonly ThemeSettings $settings) {}

    public function current(?string $context = null): Theme
    {
        $requested = $this->resolver->resolve($context);
        try {
            return $this->loader->find($requested);
        } catch (ThemeNotFoundException) {
            $fallback = $context === 'frontend'
                ? (string) config('stylist.default_frontend_theme', 'frontend')
                : (string) config('stylist.default_backend_theme', config('stylist.default_theme', 'backend'));
            if ($requested !== $fallback) {
                return $this->loader->find($fallback);
            }
            throw ThemeNotFoundException::forKey($requested);
        }
    }

    public function frontend(): Theme
    {
        return $this->current('frontend');
    }

    public function backend(): Theme
    {
        return $this->current('backend');
    }

    public function variables(): array
    {
        $theme = $this->current();
        $variant = $this->settings->variant($theme);
        $variantVars = (array) data_get($theme->variants(), $variant.'.variables', []);
        $appearanceVars = (array) data_get($theme->appearances(), $this->appearance().'.variables', []);
        $accentVars = (array) data_get($theme->accents(), $this->accent().'.variables', []);
        $settingVars = collect($this->settings->get($theme))
            ->filter(fn ($value, $key) => is_string($key) && str_starts_with($key, '--'))
            ->mapWithKeys(fn ($value, $key) => [ltrim($key, '-') => $value])
            ->all();

        return array_replace(
            (array) config('stylist.fallback_variables', []),
            $this->inheritedVariables($theme),
            $variantVars,
            $appearanceVars,
            $accentVars,
            $settingVars,
            $this->resolver->variables(),
        );
    }

    public function settings(): array
    {
        return $this->settings->get($this->current());
    }

    public function variant(): string
    {
        return $this->settings->variant($this->current());
    }

    public function appearance(): string
    {
        return $this->settings->appearance($this->current());
    }

    public function accent(): string
    {
        return $this->settings->accent($this->current());
    }

    public function all()
    {
        return $this->loader->all();
    }

    private function inheritedVariables(Theme $theme, array $seen = []): array
    {
        if (in_array($theme->key(), $seen, true)) {
            return [];
        }
        $seen[] = $theme->key();
        $parent = [];
        if ($theme->parent()) {
            try {
                $parent = $this->inheritedVariables($this->loader->find($theme->parent()), $seen);
            } catch (ThemeNotFoundException) {
            }
        }

        return array_replace($parent, $theme->variables());
    }
}