<?php

namespace EasyCorp\Bundle\EasyAdminBundle\Configuration;

use Symfony\Component\Finder\Finder;
use Twig\Loader\FilesystemLoader;

/**
 * Processes the template configuration to decide which template to use to
 * display each property in each view. It also processes the global templates
 * used when there is no entity configuration (e.g. for error pages).
 *
 * @author Javier Eguiluz <javier.eguiluz@gmail.com>
 */
class TemplateConfigPass implements ConfigPassInterface
{
    private $twigLoader;
    private $defaultBackendTemplates = [
        'layout' => '@EasyAdmin/default/layout.html.twig',
        'menu' => '@EasyAdmin/default/menu.html.twig',
        'edit' => '@EasyAdmin/default/edit.html.twig',
        'list' => '@EasyAdmin/default/list.html.twig',
        'new' => '@EasyAdmin/default/new.html.twig',
        'show' => '@EasyAdmin/default/show.html.twig',
        'action' => '@EasyAdmin/default/action.html.twig',
        'filters' => '@EasyAdmin/default/filters.html.twig',
        'exception' => '@EasyAdmin/default/exception.html.twig',
        'flash_messages' => '@EasyAdmin/default/flash_messages.html.twig',
        'paginator' => '@EasyAdmin/default/paginator.html.twig',
        'field_array' => '@EasyAdmin/default/field_array.html.twig',
        'field_association' => '@EasyAdmin/default/field_association.html.twig',
        'field_avatar' => '@EasyAdmin/default/field_avatar.html.twig',
        'field_bigint' => '@EasyAdmin/default/field_bigint.html.twig',
        'field_boolean' => '@EasyAdmin/default/field_boolean.html.twig',
        'field_country' => '@EasyAdmin/default/field_country.html.twig',
        'field_date' => '@EasyAdmin/default/field_date.html.twig',
        'field_dateinterval' => '@EasyAdmin/default/field_dateinterval.html.twig',
        'field_datetime' => '@EasyAdmin/default/field_datetime.html.twig',
        'field_datetimetz' => '@EasyAdmin/default/field_datetimetz.html.twig',
        'field_decimal' => '@EasyAdmin/default/field_decimal.html.twig',
        'field_email' => '@EasyAdmin/default/field_email.html.twig',
        'field_file' => '@EasyAdmin/default/field_file.html.twig',
        'field_float' => '@EasyAdmin/default/field_float.html.twig',
        'field_guid' => '@EasyAdmin/default/field_guid.html.twig',
        'field_id' => '@EasyAdmin/default/field_id.html.twig',
        'field_image' => '@EasyAdmin/default/field_image.html.twig',
        'field_json' => '@EasyAdmin/default/field_json.html.twig',
        'field_json_array' => '@EasyAdmin/default/field_json_array.html.twig',
        'field_integer' => '@EasyAdmin/default/field_integer.html.twig',
        'field_object' => '@EasyAdmin/default/field_object.html.twig',
        'field_percent' => '@EasyAdmin/default/field_percent.html.twig',
        'field_raw' => '@EasyAdmin/default/field_raw.html.twig',
        'field_simple_array' => '@EasyAdmin/default/field_simple_array.html.twig',
        'field_smallint' => '@EasyAdmin/default/field_smallint.html.twig',
        'field_string' => '@EasyAdmin/default/field_string.html.twig',
        'field_tel' => '@EasyAdmin/default/field_tel.html.twig',
        'field_text' => '@EasyAdmin/default/field_text.html.twig',
        'field_time' => '@EasyAdmin/default/field_time.html.twig',
        'field_toggle' => '@EasyAdmin/default/field_toggle.html.twig',
        'field_url' => '@EasyAdmin/default/field_url.html.twig',
        'label_empty' => '@EasyAdmin/default/label_empty.html.twig',
        'label_inaccessible' => '@EasyAdmin/default/label_inaccessible.html.twig',
        'label_null' => '@EasyAdmin/default/label_null.html.twig',
        'label_undefined' => '@EasyAdmin/default/label_undefined.html.twig',
    ];
    private $existingTemplates = [];

    public function __construct(FilesystemLoader $twigLoader)
    {
        $this->twigLoader = $twigLoader;
    }

    public function process(array $backendConfig)
    {
        $backendConfig = $this->processEntityTemplates($backendConfig);
        $backendConfig = $this->processDefaultTemplates($backendConfig);
        $backendConfig = $this->processFieldTemplates($backendConfig);
        $backendConfig = $this->processActionTemplates($backendConfig);

        $this->existingTemplates = [];

        return $backendConfig;
    }

    /**
     * Determines the template used to render each backend element. This is not
     * trivial because templates can depend on the entity displayed and they
     * define an advanced override mechanism.
     *
     * @param array $backendConfig
     *
     * @return array
     *
     * @throws \RuntimeException
     */
    private function processEntityTemplates(array $backendConfig)
    {
        // first, resolve the general template overriding mechanism
        // 1st level priority: easy_admin.entities.<entityName>.templates.<templateName> config option
        // 2nd level priority: easy_admin.design.templates.<templateName> config option
        // 3rd level priority: @EasyAdmin/default/<templateName>.html.twig
        foreach ($backendConfig['entities'] as $entityName => $entityConfig) {
            foreach ($this->defaultBackendTemplates as $templateName => $defaultTemplatePath) {
                $candidateTemplates = [
                    $entityConfig['templates'][$templateName] ?? '',
                    $backendConfig['design']['templates'][$templateName] ?? '',
                    $defaultTemplatePath,
                ];
                $templatePath = $this->findFirstExistingTemplate($candidateTemplates);

                if (null === $templatePath) {
                    throw new \RuntimeException(sprintf('None of the templates defined for the "%s" fragment of the "%s" entity exists (templates defined: %s).', $templateName, $entityName, implode(', ', $candidateTemplates)));
                }

                $entityConfig['templates'][$templateName] = $templatePath;
            }

            $backendConfig['entities'][$entityName] = $entityConfig;
        }

        // second, walk through all entity fields to determine their specific template
        foreach ($backendConfig['entities'] as $entityName => $entityConfig) {
            foreach (['list', 'show'] as $view) {
                foreach ($entityConfig[$view]['fields'] as $fieldName => $fieldMetadata) {
                    // if the field defines its own template, use it. Otherwise, initialize
                    // it to null because it will be resolved at runtime in the Configurator
                    $entityConfig[$view]['fields'][$fieldName]['template'] = $fieldMetadata['template'] ?? null;
                }
            }

            $backendConfig['entities'][$entityName] = $entityConfig;
        }

        return $backendConfig;
    }

    /**
     * Determines the templates used to render each backend element when no
     * entity configuration is available. It's similar to processEntityTemplates()
     * but it doesn't take into account the details of each entity.
     * This is needed for example when an exception is triggered and no entity
     * configuration is available to know which template should be rendered.
     *
     * @param array $backendConfig
     *
     * @return array
     */
    private function processDefaultTemplates(array $backendConfig)
    {
        // 1st level priority: easy_admin.design.templates.<templateName> config option
        // 2nd level priority: @EasyAdmin/default/<templateName>.html.twig
        foreach ($this->defaultBackendTemplates as $templateName => $defaultTemplatePath) {
            $candidateTemplates = [
                $backendConfig['design']['templates'][$templateName] ?? '',
                $defaultTemplatePath,
            ];
            $templatePath = $this->findFirstExistingTemplate($candidateTemplates);

            if (null === $templatePath) {
                throw new \RuntimeException(sprintf('None of the templates defined for the global "%s" template of the backend exists (templates defined: %s).', $templateName, implode(', ', $candidateTemplates)));
            }

            $backendConfig['design']['templates'][$templateName] = $templatePath;
        }

        return $backendConfig;
    }

    /**
     * Determines the template used to render each backend element. This is not
     * trivial because templates can depend on the entity displayed and they
     * define an advanced override mechanism.
     *
     * @param array $backendConfig
     *
     * @return array
     */
    private function processFieldTemplates(array $backendConfig)
    {
        foreach ($backendConfig['entities'] as $entityName => $entityConfig) {
            foreach (['list', 'show'] as $view) {
                foreach ($entityConfig[$view]['fields'] as $fieldName => $fieldMetadata) {
                    if (null !== $fieldMetadata['template']) {
                        continue;
                    }

                    // needed to add support for immutable datetime/date/time fields
                    // (which are rendered using the same templates as their non immutable counterparts)
                    if ('_immutable' === mb_substr($fieldMetadata['dataType'], -10)) {
                        $fieldTemplateName = 'field_'.mb_substr($fieldMetadata['dataType'], 0, -10);
                    } else {
                        $fieldTemplateName = 'field_'.$fieldMetadata['dataType'];
                    }

                    // primary key values are displayed unmodified to prevent common issues
                    // such as formatting its values as numbers (e.g. `1,234` instead of `1234`)
                    if ($entityConfig['primary_key_field_name'] === $fieldName) {
                        $template = $entityConfig['templates']['field_id'];
                    } elseif (\array_key_exists($fieldTemplateName, $entityConfig['templates'])) {
                        $template = $entityConfig['templates'][$fieldTemplateName];
                    } else {
                        $template = $entityConfig['templates']['label_undefined'];
                    }

                    $entityConfig[$view]['fields'][$fieldName]['template'] = $template;
                }
            }

            $backendConfig['entities'][$entityName] = $entityConfig;
        }

        return $backendConfig;
    }

    /**
     * Sets the default action template for every action, if it is not already set.
     *
     * @param array $backendConfig
     *
     * @return array
     */
    private function processActionTemplates(array $backendConfig)
    {
        foreach ($backendConfig['entities'] as $entityName => $entityConfig) {
            foreach (['list', 'show', 'edit', 'new'] as $viewName) {
                foreach ($entityConfig[$viewName]['actions'] as $actionName => $actionConfig) {
                    if (null === $actionConfig['template']) {
                        $templateName = $backendConfig['design']['templates']['action'];
                        $backendConfig['entities'][$entityName][$viewName]['actions'][$actionName]['template'] = $templateName;
                    }
                }
            }
        }

        return $backendConfig;
    }

    /**
     * @param string[] $templatePaths
     */
    private function findFirstExistingTemplate(array $templatePaths): ?string
    {
        foreach ($templatePaths as $templatePath) {
            if ('' === $templatePath) {
                continue;
            }

            // template name normalization code taken from FilesystemLoader::normalizeName()
            $templatePath = preg_replace('#/{2,}#', '/', str_replace('\\', '/', $templatePath));
            $namespace = FilesystemLoader::MAIN_NAMESPACE;

            if (isset($templatePath[0]) && '@' === $templatePath[0]) {
                if (false === $pos = strpos($templatePath, '/')) {
                    throw new \LogicException(sprintf('Malformed namespaced template name "%s" (expecting "@namespace/template_name").', $templatePath));
                }

                $namespace = substr($templatePath, 1, $pos - 1);
            }

            if (!isset($this->existingTemplates[$namespace])) {
                foreach ($this->twigLoader->getPaths($namespace) as $path) {
                    $finder = new Finder();
                    $finder->files()->in($path);

                    foreach ($finder as $templateFile) {
                        $template = $templateFile->getRelativePathname();

                        if ('\\' === \DIRECTORY_SEPARATOR) {
                            $template = str_replace('\\', '/', $template);
                        }

                        if (FilesystemLoader::MAIN_NAMESPACE !== $namespace) {
                            $template = sprintf('@%s/%s', $namespace, $template);
                        }
                        $this->existingTemplates[$namespace][$template] = true;
                    }
                }
            }

            if (null !== $templatePath && isset($this->existingTemplates[$namespace][$templatePath])) {
                return $templatePath;
            }
        }
    }
}