<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\Divi\Design;

use LIT\MCP\Abilities\Ability;
use LIT\MCP\Abilities\Annotations;
use LIT\MCP\Abilities\Errors;
use LIT\MCP\Integrations\Divi\Release\DiviFeature;
use LIT\MCP\Integrations\Divi\Release\RequiresDiviFeatures;
use WP_Error;

defined('ABSPATH') || exit;

/**
 * lit/divi-theme-options-get (spec §8.1, rulings W2, W3): the 20 whitelisted Divi theme options – per key the stored
 * value (null = unset), the value in effect (an unset tablet/phone size inherits the larger size), Divi's default,
 * type, range or choices – and the design_rev of the area. Reading needs what lit/divi-design-system needs.
 */
final class DiviThemeOptionsGetAbility implements Ability, RequiresDiviFeatures
{
    /** Fields of ThemeOptionSpec::definition() passed through as they are. */
    private const RULES = ['min', 'max', 'step', 'choices', 'inherits'];

    private const NOTES = [
        'Ändern mit lit/divi-theme-options-update: set {Schlüssel: Wert}; null setzt auf den Divi-Standard zurück.',
        'Ohne eigenen Wert erben Tablet- und Smartphone-Größen die nächstgrößere Größe (inherits).',
        'Die fünf Hauptfarben ändert lit/divi-colors-set; Buttons, Logo und SEO bleiben im Divi-Customizer.',
    ];

    public function __construct(private ThemeOptionsAdapter $options)
    {
    }

    public function name(): string
    {
        return 'lit/divi-theme-options-get';
    }

    public function label(): string
    {
        return 'Divi-Theme-Optionen lesen';
    }

    public function description(): string
    {
        return 'Liest Divis Theme-Optionen für Schriften, Schriftgrößen und Layout: je Schlüssel den gespeicherten '
            . 'Wert (null = nicht gesetzt), den wirksamen Wert, den Divi-Standard, Typ und Bereich oder Auswahl, dazu '
            . 'die design_rev. keys grenzt auf einzelne Schlüssel ein. Ändern mit lit/divi-theme-options-update.';
    }

    public function inputSchema(): array
    {
        return [
            'type' => 'object',
            'properties' => [
                'keys' => [
                    'type' => 'array',
                    'items' => ['type' => 'string', 'enum' => ThemeOptionSpec::KEYS],
                    'description' => 'Nur diese Theme-Optionen liefern (Standard: alle).',
                ],
            ],
            'additionalProperties' => false,
        ];
    }

    public function outputSchema(): ?array
    {
        return [
            'type' => 'object',
            'properties' => [
                'options' => [
                    'type' => 'array',
                    'items' => [
                        'type' => 'object',
                        'properties' => [
                            'key' => ['type' => 'string'],
                            'label' => ['type' => 'string'],
                            'type' => ['type' => 'string'],
                            'is_default' => ['type' => 'boolean'],
                        ],
                        'required' => ['key', 'label', 'type', 'value', 'effective', 'default', 'is_default'],
                    ],
                ],
                'design_rev' => ['type' => 'string'],
                'notes' => ['type' => 'array', 'items' => ['type' => 'string']],
            ],
            'required' => ['options', 'design_rev', 'notes'],
        ];
    }

    public function annotations(): array
    {
        return Annotations::read();
    }

    public function isDirect(): bool
    {
        return false;
    }

    /** Reads et_divi and the Customizer table (ThemeOptionsAdapter, ThemeOptionSpec mirror). */
    public function diviFeatures(array $input): array
    {
        return [DiviFeature::ThemeOptionRead];
    }

    public function permission(array $input): bool|WP_Error
    {
        return self::rights() ?? true;
    }

    public function execute(array $input): mixed
    {
        $refusal = self::rights();
        if ($refusal !== null) {
            return $refusal;
        }
        $keys = self::keys($input);
        if ($keys instanceof WP_Error) {
            return $keys;
        }

        $stored = ThemeOptionBook::fromDivi($this->options->read());
        $book = $stored->withoutFalse();
        $rows = [];
        foreach ($keys as $key) {
            $definition = ThemeOptionSpec::definition($key);
            $rows[] = [
                'key' => $key,
                'label' => $definition['label'],
                'type' => $definition['type'],
                'value' => $book->get($key),
                'effective' => ThemeOptionSpec::effective($key, $book->data()),
                'default' => ThemeOptionSpec::effective($key, $book->without($key)->data()),
                'is_default' => ! $book->has($key),
            ] + array_intersect_key($definition, array_flip(self::RULES));
        }

        return ['options' => $rows, 'design_rev' => $stored->rev(), 'notes' => self::NOTES];
    }

    /** Like lit/divi-design-system: whoever edits content may read the design. */
    private static function rights(): ?WP_Error
    {
        return current_user_can('edit_posts') ? null : Errors::forbidden('Keine Berechtigung, Inhalte zu bearbeiten.');
    }

    /**
     * @param array<string, mixed> $input
     * @return list<string>|WP_Error The requested keys in ThemeOptionSpec::KEYS order (all without "keys").
     */
    private static function keys(array $input): array|WP_Error
    {
        $keys = $input['keys'] ?? ThemeOptionSpec::KEYS;
        if (! is_array($keys) || ! array_is_list($keys)) {
            return Errors::invalidInput('keys muss eine Liste sein.', ['keys' => 'Liste von Theme-Optionen']);
        }
        $errors = [];
        foreach ($keys as $index => $key) {
            if (! is_string($key) || ! ThemeOptionSpec::isKey($key)) {
                $errors[sprintf('keys[%d]', $index)] = 'unbekannte Theme-Option; erlaubt sind die Schlüssel aus '
                    . 'lit/divi-theme-options-get ohne keys';
            }
        }
        if ($errors !== []) {
            return Errors::invalidInput('Unbekannte Theme-Optionen.', $errors);
        }

        return array_values(array_intersect(ThemeOptionSpec::KEYS, $keys));
    }
}