<?php

namespace App\Services\Project;

use App\Http\Resources\API\ProjectGanttResource;
use App\Http\Resources\API\ProjectGroupViewTaskResource;
use App\Models\Enums\ProjectStatus;
use App\Models\Project;
use App\Models\Requirement;
use App\Models\Task;
use App\Models\User;
use Carbon\Carbon;
use Illuminate\Support\Collection;

class ProjectGanttService
{
    public function gantt(Project $project, string $group): array
    {
        $groupTasks = $this->getGroupTask($project, $group);

        $groups = $groupTasks->keys()->filter();

        $groupNamesKeyBy = $this->getGroupNamesKeyBy($groups, $group);

        $items = [];
        foreach(["", ...$groups] as $groupKey) {
            if (! isset($groupTasks[$groupKey])) {
                continue;
            }

            $treeTasks = make_tree($groupTasks[$groupKey]->toArray());
            $groupUniqueKey = uniqid();
            $items[] = $this->topGroupFormat(
                $groupUniqueKey,
                isset($groupNamesKeyBy[$groupKey]) ? $groupNamesKeyBy[$groupKey]['name'] : "Empty"
            );
            $tasks = $this->flattenTasks($treeTasks);

            foreach ($tasks as $task) {
                $items[] = $this->taskFormat($task, $groupUniqueKey);
            }
        }

        return $items;
    }

    protected function topGroupFormat(string $id, string $name)
    {
        return [
            'id' => $id,
            'text' => $name,
            'parent' => 0,
            'start_date' => null,
            'duration' => null,
            'progress' => 0,
            'assign_to' => null,
            'open' => true,
        ];
    }

    protected function taskFormat(array $task, string $topId)
    {
        $progress = 0;
        $begin = $task['begin'] ? Carbon::parse($task['begin']) : Carbon::parse($task['created_at']);
        $end = $task['end'] ? Carbon::parse($task['end']) : $begin->copy()->addYears(2);
        $now = Carbon::now();

        if ($now->gt($end)) {
            $progress = 1;
        }

        if ($now->gt($begin) && $end->gt($now)) {
            $totalDay = $end->diffInDays($begin);
            $day = $now->diffInDays($begin);
            $progress = (float)number_format($day / $totalDay, 4);
        }

        return [
            'id' => $task['id'],
            'text' => $task['name'],
            'parent' => $task['parent_id'] > 0 ? $task['parent_id'] : $topId ,
            'start_date' => $task['begin'],
            'duration' => $end->diffInDays($begin),
            'progress' => $progress,
            'assign_to' =>$task['assign']?User::query()->where('id',$task['assign'])->first()->name:null,
            'open' => true,
        ];
    }

    protected function flattenTasks($tasks) {
        $items = [];

        foreach ($tasks as $task) {
            $items[] = $task;
            if (!empty($task['children'])) {
                $items = array_merge($items, $this->flattenTasks($task['children']));
            }
            unset($task['children']);
        }

        return $items;
    }

    protected function getGroupNamesKeyBy(Collection $groups, string $group): array
    {
        $groupsFormat = $groups->map(fn($group) => ['id' => $group, 'name' => $group]);
        $groupNames = match ($group) {
            "requirement_id" => Requirement::query()->whereIn("id", $groups)->selectRaw("id,title as name")->get(),
            "task_type" => $groupsFormat,
            "assign" => User::query()->whereIn("id", $groups)->get(['id', 'name']),
        };

        return $groupNames->keyBy("id")->toArray();
    }

    protected function getGroupTask(
        Project $project,
        string $group,
    ): \Illuminate\Database\Eloquent\Collection|\Illuminate\Support\Collection|array
    {
        return Task::query()
            ->with(['assignTo', 'finishedBy'])
            ->where("project_id", $project->id)
            ->get()
            ->groupBy($group);
    }
}