<?php

namespace Dcat\Admin\Form\Field;

use Dcat\Admin\Form;
use Dcat\Admin\Form\Field;
use Dcat\Admin\Form\NestedForm;
use Dcat\Admin\Support\Helper;
use Illuminate\Support\Arr;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\Str;

/**
 * Class HasMany.
 */
class HasMany extends Field
{
    use Form\ResolveField;

    /**
     * Relation name.
     *
     * @var string
     */
    protected $relationName;

    /**
     * @var string
     */
    protected $parentRelationName;

    /**
     * @var string|int
     */
    protected $parentKey;

    /**
     * Relation key name.
     *
     * @var string
     */
    protected $relationKeyName = 'id';

    /**
     * Form builder.
     *
     * @var \Closure
     */
    protected $builder = null;

    /**
     * Form data.
     *
     * @var array
     */
    protected $value = [];

    /**
     * View Mode.
     *
     * Supports `default` and `tab` currently.
     *
     * @var string
     */
    protected $viewMode = 'default';

    /**
     * Available views for HasMany field.
     *
     * @var array
     */
    protected $views = [
        'default' => 'admin::form.hasmany',
        'tab'     => 'admin::form.hasmanytab',
        'table'   => 'admin::form.hasmanytable',
    ];

    /**
     * Options for template.
     *
     * @var array
     */
    protected $options = [
        'allowCreate' => true,
        'allowDelete' => true,
    ];

    protected $columnClass;

    /**
     * Create a new HasMany field instance.
     *
     * @param $relationName
     * @param  array  $arguments
     */
    public function __construct($relationName, $arguments = [])
    {
        $this->relationName = $relationName;

        $this->column = $relationName;

        $this->columnClass = $this->formatClass($relationName);

        if (count($arguments) == 1) {
            $this->label = $this->formatLabel();
            $this->builder = $arguments[0];
        }

        if (count($arguments) == 2) {
            [$this->label, $this->builder] = $arguments;
        }
    }

    protected function formatClass(string $column)
    {
        return str_replace('.', '-', $column);
    }

    /**
     * Get validator for this field.
     *
     * @param  array  $input
     * @return bool|Validator
     */
    public function getValidator(array $input)
    {
        if (! Arr::has($input, $this->column)) {
            return false;
        }

        $form = $this->buildNestedForm();

        $rules = $attributes = $messages = [];

        /* @var Field $field */
        foreach ($form->fields() as $field) {
            if (! $fieldRules = $field->getRules()) {
                continue;
            }

            File::deleteRules($field, $fieldRules);

            $column = $field->column();

            $this->normalizeValidatorInput($field, $input);

            if (is_array($column)) {
                foreach ($column as $key => $name) {
                    $rules[$name.$key] = $fieldRules;
                }

                $this->resetInputKey($input, $column);
            } else {
                $rules[$column] = $fieldRules;
            }

            $attributes = array_merge(
                $attributes,
                $this->formatValidationAttribute($input, $field->label(), $column)
            );

            $messages = array_merge(
                $messages,
                $this->formatValidationMessages($input, $field->getValidationMessages())
            );
        }

        Arr::forget($rules, NestedForm::REMOVE_FLAG_NAME);

        if (empty($rules)) {
            return false;
        }

        $newRules = [];
        $newInput = [];

        foreach ($rules as $column => $rule) {
            foreach (array_keys(Arr::get($input, $this->column)) as $key) {
                if (Arr::get($input, "{$this->column}.{$key}.".NestedForm::REMOVE_FLAG_NAME)) {
                    continue;
                }

                $subKey = "{$this->column}.{$key}.{$column}";

                $newRules[$subKey] = $rule;

                $newInput[$subKey] = $ruleValue = Arr::get($input, "{$this->column}.$key.$column");

                if (is_array($ruleValue)) {
                    foreach ($ruleValue as $vkey => $value) {
                        $newInput["{$subKey}.{$vkey}"] = $value;
                    }
                }
            }
        }

        $newInput += $input;

        if ($hasManyRules = $this->getRules()) {
            if (! Arr::has($input, $this->column)) {
                return false;
            }

            $newInput += $this->sanitizeInput($input, $this->column);

            $newRules[$this->column] = $hasManyRules;
            $attributes[$this->column] = $this->label;
        }

        return Validator::make($newInput, $newRules, array_merge($this->getValidationMessages(), $messages), $attributes);
    }

    protected function normalizeValidatorInput(Field $field, array &$input)
    {
        if (
            $field instanceof MultipleSelect
            || $field instanceof Checkbox
            || $field instanceof Tags
        ) {
            foreach (array_keys(Arr::get($input, $this->column)) as $key) {
                $value = $input[$this->column][$key][$field->column()];
                $input[$this->column][$key][$field->column()] = array_filter($value, function ($v) {
                    return $v !== null;
                });
            }
        }
    }

    /**
     * Format validation messages.
     *
     * @param  array  $input
     * @param  array  $messages
     * @return array
     */
    protected function formatValidationMessages(array $input, array $messages)
    {
        $result = [];
        foreach (Arr::get($input, $this->column) as $key => &$value) {
            $newKey = $this->column.'.'.$key;

            foreach ($messages as $k => $message) {
                $result[$newKey.'.'.$k] = $message;
            }
        }

        return $result;
    }

    /**
     * Format validation attributes.
     *
     * @param  array  $input
     * @param  string  $label
     * @param  string  $column
     * @return array
     */
    protected function formatValidationAttribute($input, $label, $column)
    {
        $new = $attributes = [];

        if (is_array($column)) {
            foreach ($column as $index => $col) {
                $new[$col.$index] = $col;
            }
        }

        foreach (array_keys(Arr::dot($input)) as $key) {
            if (is_string($column)) {
                if (Str::endsWith($key, ".$column")) {
                    $attributes[$key] = $label;
                }
            } else {
                foreach ($new as $k => $val) {
                    if (Str::endsWith($key, ".$k")) {
                        $attributes[$key] = $label."[$val]";
                    }
                }
            }
        }

        return $attributes;
    }

    /**
     * Reset input key for validation.
     *
     * @param  array  $input
     * @param  array  $column  $column is the column name array set
     * @return void.
     */
    protected function resetInputKey(array &$input, array $column)
    {
        /**
         * flip the column name array set.
         *
         * for example, for the DateRange, the column like as below
         *
         * ["start" => "created_at", "end" => "updated_at"]
         *
         * to:
         *
         * [ "created_at" => "start", "updated_at" => "end" ]
         */
        $column = array_flip($column);

        /**
         * $this->column is the inputs array's node name, default is the relation name.
         *
         * So... $input[$this->column] is the data of this column's inputs data
         *
         * in the HasMany relation, has many data/field set, $set is field set in the below
         */
        foreach (Arr::get($input, $this->column) as $index => $set) {

            /*
             * foreach the field set to find the corresponding $column
             */
            foreach ($set as $name => $value) {
                /*
                 * if doesn't have column name, continue to the next loop
                 */
                if (! array_key_exists($name, $column)) {
                    continue;
                }

                /**
                 * example:  $newKey = created_atstart.
                 *
                 * Σ( ° △ °|||)︴
                 *
                 * I don't know why a form need range input? Only can imagine is for range search....
                 */
                $newKey = $name.$column[$name];

                /*
                 * set new key
                 */
                Arr::set($input, "{$this->column}.$index.$newKey", $value);
                /*
                 * forget the old key and value
                 */
                Arr::forget($input, "{$this->column}.$index.$name");
            }
        }
    }

    /**
     * Prepare input data for insert or update.
     *
     * @param  array  $input
     * @return array
     */
    protected function prepareInputValue($input)
    {
        $form = $this->buildNestedForm();

        return array_values(
            $form->setOriginal($this->original, $this->getKeyName())->prepare($input)
        );
    }

    public function setParentRelationName($name, $parentKey)
    {
        $this->parentRelationName = $name;
        $this->parentKey = $parentKey;

        return $this;
    }

    public function getNestedFormColumnName()
    {
        if ($this->parentRelationName) {
            $key = $this->parentKey ?? (NestedForm::DEFAULT_KEY_PREFIX.NestedForm::DEFAULT_PARENT_KEY_NAME);

            return $this->parentRelationName.'.'.$key.'.'.$this->column;
        }

        return $this->column;
    }

    protected function getNestedFormDefaultKeyName()
    {
        if ($this->parentRelationName) {
            // hasmany嵌套table时，需要重新设置行的默认key
            return $this->parentRelationName.'_NKEY_';
        }
    }

    protected function setNestedFormDefaultKey(Form\NestedForm $form)
    {
        if ($this->parentRelationName) {
            // hasmany嵌套table时需要特殊处理
            $form->setDefaultKey(Form\NestedForm::DEFAULT_KEY_PREFIX.$this->getNestedFormDefaultKeyName());
        }
    }

    /**
     * Build a Nested form.
     *
     * @param  null  $key
     * @return NestedForm
     */
    public function buildNestedForm($key = null)
    {
        $form = new Form\NestedForm($this->getNestedFormColumnName(), $key);

        $this->setNestedFormDefaultKey($form);

        $form->setForm($this->form);

        $form->setResolvingFieldCallbacks($this->resolvingFieldCallbacks);

        call_user_func($this->builder, $form);

        $form->hidden($this->getKeyName());

        $form->hidden(NestedForm::REMOVE_FLAG_NAME)->default(0)->addElementClass(NestedForm::REMOVE_FLAG_CLASS);

        return $form;
    }

    /**
     * Get the HasMany relation key name.
     *
     * @return string
     */
    public function getKeyName()
    {
        if (is_null($this->form)) {
            return;
        }

        return $this->relationKeyName;
    }

    /**
     * @param  string  $relationKeyName
     */
    public function setRelationKeyName(?string $relationKeyName)
    {
        $this->relationKeyName = $relationKeyName;

        return $this;
    }

    /**
     * Set view mode.
     *
     * @param  string  $mode  currently support `tab` mode.
     * @return $this
     *
     * @author Edwin Hui
     */
    public function mode($mode)
    {
        $this->viewMode = $mode;

        return $this;
    }

    /**
     * Use tab mode to showing hasmany field.
     *
     * @return HasMany
     */
    public function useTab()
    {
        return $this->mode('tab');
    }

    /**
     * Use table mode to showing hasmany field.
     *
     * @return HasMany
     */
    public function useTable()
    {
        return $this->mode('table');
    }

    /**
     * Build Nested form for related data.
     *
     * @return array
     *
     * @throws \Exception
     */
    protected function buildRelatedForms()
    {
        if (is_null($this->form)) {
            return [];
        }

        $forms = [];

        /*
         * If redirect from `exception` or `validation error` page.
         *
         * Then get form data from session flash.
         *
         * Else get data from database.
         */
        foreach (Helper::array($this->value()) as $idx => $data) {
            $key = Arr::get($data, $this->getKeyName(), $idx);

            $forms[$key] = $this->buildNestedForm($key)
                ->fill($data);
        }

        return $forms;
    }

    /**
     * Disable create button.
     *
     * @return $this
     */
    public function disableCreate()
    {
        $this->options['allowCreate'] = false;

        return $this;
    }

    /**
     * Disable delete button.
     *
     * @return $this
     */
    public function disableDelete()
    {
        $this->options['allowDelete'] = false;

        return $this;
    }

    public function value($value = null)
    {
        if ($value === null) {
            return Helper::array(parent::value($value));
        }

        return parent::value($value);
    }

    /**
     * Render the `HasMany` field.
     *
     * @return \Illuminate\View\View|string
     *
     * @throws \Exception
     */
    public function render()
    {
        if (! $this->shouldRender()) {
            return '';
        }

        if ($this->viewMode == 'table') {
            return $this->renderTable();
        }

        // specify a view to render.
        $this->view = $this->view ?: $this->views[$this->viewMode];

        $this->addVariables([
            'forms'          => $this->buildRelatedForms(),
            'template'       => $this->buildNestedForm()->render(),
            'relationName'   => $this->relationName,
            'options'        => $this->options,
            'count'          => count($this->value()),
            'columnClass'    => $this->columnClass,
        ]);

        return parent::render();
    }

    /**
     * Render the `HasMany` field for table style.
     *
     * @return mixed
     *
     * @throws \Exception
     */
    protected function renderTable()
    {
        $headers = [];
        $fields = [];
        $hidden = [];

        /* @var Field $field */
        foreach ($this->buildNestedForm()->fields() as $field) {
            if (is_a($field, Hidden::class)) {
                $hidden[] = $field->render();
            } else {
                /* Hide label and set field width 100% */
                $field->setLabelClass(['hidden']);
                $field->width(12, 0);
                $fields[] = $field->render();
                $headers[] = $field->label();
            }
        }

        /* Build row elements */
        $template = array_reduce($fields, function ($all, $field) {
            $all .= "<td>{$field}</td>";

            return $all;
        }, '');

        /* Build cell with hidden elements */
        $template .= '<td class="hidden">'.implode('', $hidden).'</td>';

        // specify a view to render.
        $this->view = $this->view ?: $this->views[$this->viewMode];

        $this->addVariables([
            'headers'      => $headers,
            'forms'        => $this->buildRelatedForms(),
            'template'     => $template,
            'relationName' => $this->relationName,
            'options'      => $this->options,
            'count'        => count($this->value()),
            'columnClass'  => $this->columnClass,
            'parentKey'    => $this->getNestedFormDefaultKeyName(),
        ]);

        return parent::render();
    }
}