<?php

declare(strict_types=1);

namespace Agent001\Admin;

\defined( 'ABSPATH' ) || exit;

use Agent001\Config\AgentId;
use Agent001\Config\Settings;
use Agent001\Sync\SyncRunner;

final class SettingsPage
{
    public const PAGE_SLUG   = 'agent001-settings';
    public const CAPABILITY  = 'manage_options';
    public const SAVE_ACTION = 'agent001_save_settings';

    private Settings $settings;

    private SyncRunner $syncRunner;

    private SyncProgress $progress;

    private AgentSelectionController $agents;

    private string $pluginPath;

    private string $pluginUrl;

    private string $version;

    private Onboarding $onboarding;

    public function __construct(
        Settings $settings,
        SyncRunner $syncRunner,
        SyncProgress $progress,
        AgentSelectionController $agents,
        string $pluginPath,
        string $pluginUrl,
        string $version,
        Onboarding $onboarding
    ) {
        $this->settings   = $settings;
        $this->syncRunner = $syncRunner;
        $this->progress   = $progress;
        $this->agents     = $agents;
        $this->pluginPath = $pluginPath;
        $this->pluginUrl  = $pluginUrl;
        $this->version    = $version;
        $this->onboarding = $onboarding;
    }

    public function register(): void
    {
        \add_action( 'admin_menu', [ $this, 'addMenuPage' ] );
        \add_action( 'admin_post_' . self::SAVE_ACTION, [ $this, 'handleSubmit' ] );
        \add_action( 'admin_enqueue_scripts', [ $this, 'enqueueAssets' ] );
    }

    public function addMenuPage(): void
    {
        \add_menu_page( 'Agent001', 'Agent001', self::CAPABILITY, self::PAGE_SLUG, [ $this, 'render' ], 'dashicons-format-chat' );
    }

    public function enqueueAssets( string $hook ): void
    {
        if ( $hook !== 'toplevel_page_' . self::PAGE_SLUG ) {
            return;
        }

        \wp_enqueue_style(
            'agent001-sync',
            $this->pluginUrl . 'assets/css/agent001-sync.css',
            [],
            $this->version
        );

        \wp_enqueue_script(
            'agent001-sync',
            $this->pluginUrl . 'assets/js/agent001-sync.js',
            [],
            $this->version,
            true
        );

        \wp_enqueue_script(
            'agent001-categories',
            $this->pluginUrl . 'assets/js/agent001-categories.js',
            [],
            $this->version . '.' . (string) \filemtime( $this->pluginPath . 'assets/js/agent001-categories.js' ),
            true
        );

        \wp_localize_script(
            'agent001-sync',
            'Agent001Sync',
            [
                'ajaxUrl'      => \admin_url( 'admin-ajax.php' ),
                'nonce'        => \wp_create_nonce( SyncAjaxController::NONCE ),
                'actions'      => [
                    'start'  => SyncAjaxController::START_ACTION,
                    'status' => SyncAjaxController::STATUS_ACTION,
                ],
                'pollInterval' => 5000,
                'i18n'         => [
                    'syncNow'  => \__( 'Sync now', 'agent001-support-assistant-for-woocommerce' ),
                    'syncing'  => \__( 'Syncing…', 'agent001-support-assistant-for-woocommerce' ),
                    'idle'     => \__( 'Idle', 'agent001-support-assistant-for-woocommerce' ),
                    'queued'   => \__( 'Queued…', 'agent001-support-assistant-for-woocommerce' ),
                    'reading'  => \__( 'Reading products…', 'agent001-support-assistant-for-woocommerce' ),
                    'posting'  => \__( 'Sending to API…', 'agent001-support-assistant-for-woocommerce' ),
                    'indexing' => \__( 'Saving…', 'agent001-support-assistant-for-woocommerce' ),
                    'indexingHint' => \__( 'Large catalogs can take several minutes.', 'agent001-support-assistant-for-woocommerce' ),
                    'done'   => \__( 'Sync completed.', 'agent001-support-assistant-for-woocommerce' ),
                    'error'    => \__( 'Sync failed.', 'agent001-support-assistant-for-woocommerce' ),
                    'conflict' => \__( 'Another sync is already running.', 'agent001-support-assistant-for-woocommerce' ),
                    'network'  => \__( 'Network error. Retrying…', 'agent001-support-assistant-for-woocommerce' ),
                ],
            ]
        );
    }

    public function render(): void
    {
        if ( ! \current_user_can( self::CAPABILITY ) ) {
            return;
        }

        $apiKeyLocked        = $this->settings->apiKeyIsLocked();
        $isConnected         = $this->settings->hasApiKey();
        $connectedSite       = $this->settings->connectedSite();
        $accountName         = $this->settings->accountName();
        $progress            = $this->progress->current();
        $selectedCatIds      = $this->settings->syncCategories();
        $availableCategories = $this->fetchAvailableCategories();

        $availableAgents   = [];
        $selectedAgentIds  = $this->settings->selectedAgentIds();
        $agentsFetchFailed = false;
        if ( $isConnected ) {
            $cached = \get_transient( AgentSelectionController::AGENTS_TRANSIENT );
            $cacheHasAgentStatus = is_array( $cached ) && isset( $cached['agents'] ) && is_array( $cached['agents'] )
                && array_filter( $cached['agents'], static fn( $agent ): bool => ! is_array( $agent ) || ! array_key_exists( 'active', $agent ) ) === [];
            if ( is_array( $cached ) && isset( $cached['agents'] ) && ! empty( $cached['account_name'] ) && $cacheHasAgentStatus ) {
                $availableAgents  = $cached['agents'];
                $cachedIds        = is_array( $cached['selected_ids'] ?? null ) ? AgentId::normalizeList( $cached['selected_ids'] ) : [];
                $selectedAgentIds = $cachedIds !== [] ? $cachedIds : $selectedAgentIds;
            } else {
                $agentsPayload = $this->agents->fetchAgents();
                if ( $agentsPayload === null ) {
                    $agentsFetchFailed = true;
                } else {
                    $availableAgents  = $agentsPayload['agents'];
                    $selectedAgentIds = $agentsPayload['selected_ids'] !== []
                        ? $agentsPayload['selected_ids']
                        : $selectedAgentIds;
                }
            }
        }

        $isOnboarding = $this->onboarding->isActive();
        $onboardingPaused = $this->onboarding->isPaused();
        $setupStep = $this->onboarding->step();
        $onboarding = $this->onboarding;
        $backendUrl = $this->settings->backendBaseUrl();
        echo '<div class="wrap"><h1>Agent001</h1>';
        echo '<div class="notice notice-warning inline agent001-cache-notice" role="status">';
        echo '<p class="agent001-cache-notice__title">' . \esc_html__( 'Chat not visible on your store? Clear your site cache.', 'agent001-support-assistant-for-woocommerce' ) . '</p>';
        echo '<p>' . \esc_html__( 'Agent001 clears the cache of popular caching plugins automatically. If your store also uses a hosting cache or a CDN such as Cloudflare, clear it manually after finishing setup or changing the agent, then reload your store page.', 'agent001-support-assistant-for-woocommerce' ) . '</p>';
        echo '</div>';
        \settings_errors( 'agent001' );
        echo '<form method="post" action="' . \esc_url( \admin_url( 'admin-post.php' ) ) . '">';
        echo '<input type="hidden" name="action" value="' . \esc_attr( self::SAVE_ACTION ) . '">';
        \wp_nonce_field( self::SAVE_ACTION, '_agent001_nonce' );
        include $this->pluginPath . 'src/Admin/views/settings-page.php';
        if ( ! $isOnboarding && $isConnected ) {
            \submit_button( \__( 'Save changes', 'agent001-support-assistant-for-woocommerce' ) );
        }
        echo '</form></div>';
    }

    public function handleSubmit(): void
    {
        if ( ! \current_user_can( self::CAPABILITY ) ) {
            \wp_die( \esc_html__( 'Permission denied.', 'agent001-support-assistant-for-woocommerce' ), '', [ 'response' => 403 ] );
        }

        if ( isset( $_POST['agent001_toggle_agent'] ) ) {
            $this->handleAgentToggle();
            return;
        }

        $this->handleSave();
        if ( \get_settings_errors( 'agent001' ) === [] ) {
            \add_settings_error( 'agent001', 'saved', \__( 'Settings saved.', 'agent001-support-assistant-for-woocommerce' ), 'success' );
        }
        \set_transient( 'settings_errors', \get_settings_errors(), 30 );
        \wp_safe_redirect( \add_query_arg( 'settings-updated', 'true', $this->onboarding->settingsUrl() ) );
        exit;
    }

    private function handleAgentToggle(): void
    {
        \check_admin_referer( self::SAVE_ACTION, '_agent001_nonce' );

        $rawAgentId = isset( $_POST['agent001_toggle_agent'] ) && is_scalar( $_POST['agent001_toggle_agent'] )
            ? \sanitize_text_field( \wp_unslash( (string) $_POST['agent001_toggle_agent'] ) )
            : '';
        $rawActive = isset( $_POST['agent001_toggle_active'] ) && is_scalar( $_POST['agent001_toggle_active'] )
            ? (string) \wp_unslash( $_POST['agent001_toggle_active'] )
            : '';

        $toggleAgentId = AgentId::normalize( $rawAgentId );
        if ( $toggleAgentId === '' || ! in_array( $rawActive, [ '0', '1' ], true ) ) {
            \add_settings_error( 'agent001', 'agent_toggle_error', \__( 'Invalid agent status update.', 'agent001-support-assistant-for-woocommerce' ) );
        } else {
            $error = $this->agents->setAgentActive( $toggleAgentId, $rawActive === '1' );
            if ( $error !== null ) {
                \add_settings_error( 'agent001', 'agent_toggle_error', $error );
            } else {
                \add_settings_error(
                    'agent001',
                    'agent_toggle_success',
                    $rawActive === '1'
                        ? \__( 'Agent enabled.', 'agent001-support-assistant-for-woocommerce' )
                        : \__( 'Agent disabled.', 'agent001-support-assistant-for-woocommerce' ),
                    'success'
                );
            }
        }

        \set_transient( 'settings_errors', \get_settings_errors(), 30 );
        \wp_safe_redirect( $this->onboarding->settingsUrl() );
        exit;
    }

    /**
     * @return array<int, array{id: int, name: string, parent: int, count: int, depth: int}>
     */
    private function fetchAvailableCategories(): array
    {
        if ( ! \taxonomy_exists( 'product_cat' ) ) {
            return [];
        }

        $terms = \get_terms(
            [
                'taxonomy'   => 'product_cat',
                'hide_empty' => false,
                'orderby'    => 'name',
            ]
        );

        if ( ! is_array( $terms ) ) {
            return [];
        }

        $byParent = [];
        foreach ( $terms as $term ) {
            $byParent[ (int) $term->parent ][] = $term;
        }

        $ordered = [];
        $walker  = static function ( int $parent, int $depth ) use ( &$walker, &$byParent, &$ordered ): void {
            if ( ! isset( $byParent[ $parent ] ) ) {
                return;
            }
            foreach ( $byParent[ $parent ] as $term ) {
                $ordered[] = [
                    'id'     => (int) $term->term_id,
                    'name'   => (string) $term->name,
                    'parent' => (int) $term->parent,
                    'count'  => (int) $term->count,
                    'depth'  => $depth,
                ];
                $walker( (int) $term->term_id, $depth + 1 );
            }
        };

        $walker( 0, 0 );

        return $ordered;
    }

    public function handleSave(): void
    {
        if ( ! \current_user_can( self::CAPABILITY ) ) {
            return;
        }

        \check_admin_referer( self::SAVE_ACTION, '_agent001_nonce' );

        if ( $this->progress->isRunning() ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Wait for the current synchronization to finish before changing the agent or products.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }

        $rawPost = isset( $_POST['agent001_settings'] ) && is_array( $_POST['agent001_settings'] )
            // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- nested values are sanitized below per type.
            ? \map_deep( \wp_unslash( $_POST['agent001_settings'] ), 'sanitize_text_field' )
            : [];
        $raw     = is_array( $rawPost ) ? $rawPost : [];
        if ( $this->onboarding->isActive() && $this->onboarding->step() === 1 ) {
            return;
        }
        if ( ! isset( $raw['agent_id'] ) || ! is_scalar( $raw['agent_id'] ) ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Select an agent before saving.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }
        $rawCats = isset( $raw['sync_categories'] ) && is_array( $raw['sync_categories'] )
            ? $raw['sync_categories']
            : [];
        $rawAgentId = isset( $raw['agent_id'] ) ? (string) $raw['agent_id'] : '';
        $selectedId = AgentId::normalize( $rawAgentId );
        if ( $rawAgentId !== '' && $selectedId === '' ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Invalid agent selection.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }

        $ids = [];
        foreach ( $rawCats as $value ) {
            if ( ! is_scalar( $value ) || ! ctype_digit( (string) $value ) ) {
                \add_settings_error( 'agent001', 'save_error', \__( 'Invalid product category selection.', 'agent001-support-assistant-for-woocommerce' ) );
                return;
            }
            $id = (int) $value;
            if ( $id > 0 ) {
                $ids[] = $id;
            }
        }
        $newCategoryIds = array_values( array_unique( $ids ) );
        sort( $newCategoryIds );
        $availableCategoryIds = array_column( $this->fetchAvailableCategories(), 'id' );
        if ( $availableCategoryIds !== [] && $newCategoryIds === [] ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Select at least one product category.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }
        if ( array_diff( $newCategoryIds, $availableCategoryIds ) !== [] ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Invalid product category selection.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }

        $previousCategoryIds = $this->settings->syncCategories();
        sort( $previousCategoryIds );

        $previousAgentIds = $this->settings->selectedAgentIds();
        sort( $previousAgentIds );

        $agentIds = [];
        if ( $selectedId !== '' ) {
            $agentIds[] = $selectedId;
        }
        $newAgentIds = array_values( array_unique( $agentIds ) );
        sort( $newAgentIds );

        if ( $this->onboarding->isActive() && $agentIds === [] ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'Select an agent to continue setup.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }

        if ( $this->settings->hasApiKey() ) {
            $error = $this->agents->saveSelection( $agentIds );
            if ( $error !== null ) {
                \add_settings_error( 'agent001', 'save_error',
                    sprintf(
                        /* translators: %s: error message from remote */
                        \__( 'Agent selection: %s', 'agent001-support-assistant-for-woocommerce' ),
                        $error
                    )
                );
                return;
            }
        }

        $this->settings->setSyncCategories( $newCategoryIds );

        if ( $this->onboarding->isActive() && $this->settings->selectedAgentEmbedToken() === '' ) {
            \add_settings_error( 'agent001', 'save_error', \__( 'The selected agent has no widget token. Refresh the agent list or check the agent settings in Agent001, then try again.', 'agent001-support-assistant-for-woocommerce' ) );
            return;
        }

        $selectionChanged = ( $newCategoryIds !== $previousCategoryIds )
            || ( $newAgentIds !== $previousAgentIds );

        $needsFirstSync = $this->onboarding->isActive() && ! $this->onboarding->canFinish();
        if ( ( $selectionChanged || $needsFirstSync ) && $this->settings->hasApiKey() && $this->settings->hasSelectedAgents()
            && ! $this->progress->isRunning() ) {
            $this->syncRunner->schedule();
        }
    }
}