<?php

namespace App\Services;

use App\Models\ChecklistTemplate;
use App\Models\DataCentre;
use App\Models\ReportingCycle;
use App\Models\Submission;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class SubmissionWorkflowService
{
    public function __construct(protected FormulaService $formulaService) {}

    /**
     * Dapatkan atau cipta serahan draf untuk pusat data + kitaran tertentu.
     */
    public function findOrCreateDraft(DataCentre $dataCentre, ReportingCycle $cycle): Submission
    {
        $consultantId = $dataCentre->current_consultant_id;

        if (! $consultantId) {
            throw ValidationException::withMessages([
                'data_centre_id' => 'Pusat data ini tiada perunding aktif. Sila hubungi JPP.',
            ]);
        }

        return Submission::firstOrCreate(
            [
                'data_centre_id' => $dataCentre->id,
                'reporting_cycle_id' => $cycle->id,
            ],
            [
                'consultant_id' => $consultantId,
                'checklist_template_id' => $cycle->checklist_template_id ?? ChecklistTemplate::activeTemplate()?->id,
                'status' => 'draf',
            ]
        );
    }

    /**
     * Simpan jawapan senarai semak (draf). $answers = [item_id => [value, unit, page_reference, consultant_note]]
     */
    public function saveAnswers(Submission $submission, array $answers): void
    {
        DB::transaction(function () use ($submission, $answers) {
            foreach ($answers as $itemId => $data) {
                $submission->answers()->updateOrCreate(
                    ['checklist_item_id' => $itemId],
                    [
                        'value' => $data['value'] ?? null,
                        'unit' => $data['unit'] ?? null,
                        'page_reference' => $data['page_reference'] ?? null,
                        'consultant_note' => $data['consultant_note'] ?? null,
                    ]
                );
            }

            // Kira semula nilai formula (A, B, C, D, E ...).
            $submission->load('answers.item');
            $this->formulaService->recalculateAndStore($submission);
        });
    }

    /**
     * Hantar serahan secara muktamad (draf -> baru).
     */
    public function submit(Submission $submission, User $user): void
    {
        if ($submission->is_locked) {
            throw ValidationException::withMessages(['status' => 'Serahan telah dikunci dan tidak boleh dihantar semula.']);
        }

        // Mesti ada sekurang-kurangnya satu laporan PDF aktif sebelum hantar.
        if (! $submission->activeDocument()->exists()) {
            throw ValidationException::withMessages(['document' => 'Sila muat naik laporan PDF sebelum menghantar serahan.']);
        }

        $from = $submission->status;
        // Jika sedang dalam pembetulan, hantar semula sebagai 'dalam_tindakan'.
        $to = $from === 'pembetulan_perunding' ? 'dalam_tindakan' : 'baru';

        $this->changeStatus($submission, $to, $user, 'Serahan dihantar oleh perunding.', [
            'submitted_at' => now(),
            'submitted_by' => $user->id,
        ]);

        $this->formulaService->recalculateAndStore($submission);
    }

    /**
     * Tukar status serahan dengan rekod sejarah & audit.
     */
    public function changeStatus(Submission $submission, string $to, User $user, ?string $notes = null, array $extra = []): void
    {
        DB::transaction(function () use ($submission, $to, $user, $notes, $extra) {
            $from = $submission->status;

            $submission->fill(array_merge(['status' => $to], $extra));
            $submission->save();

            $submission->statusHistories()->create([
                'from_status' => $from,
                'to_status' => $to,
                'changed_by' => $user->id,
                'notes' => $notes,
            ]);

            activity('serahan')
                ->performedOn($submission)
                ->causedBy($user)
                ->withProperties(['from' => $from, 'to' => $to, 'notes' => $notes])
                ->log("Status serahan ditukar daripada {$from} kepada {$to}");
        });
    }

    public function lock(Submission $submission, User $user, ?string $reason = null): void
    {
        $submission->update([
            'is_locked' => true,
            'locked_by' => $user->id,
            'locked_at' => now(),
            'lock_reason' => $reason,
        ]);

        activity('serahan')->performedOn($submission)->causedBy($user)
            ->withProperties(['reason' => $reason])->log('Serahan dikunci');
    }

    public function unlock(Submission $submission, User $user, string $reason): void
    {
        $submission->update([
            'is_locked' => false,
            'lock_reason' => $reason,
            'locked_by' => $user->id,
            'locked_at' => now(),
        ]);

        activity('serahan')->performedOn($submission)->causedBy($user)
            ->withProperties(['reason' => $reason])->log('Serahan dibuka semula');
    }
}