feat: add shift management functionality

app/Services/Shift/ShiftScheduleService.php

@@ -0,0 +1,200 @@
+<?php
+
+namespace App\Services\Shift;
+
+use App\Enums\DocumentStatusEnum;
+use App\Enums\ShiftDayEnum;
+use App\Enums\UserEnum;
+use App\Models\Shift;
+use App\Models\User;
+use Carbon\Carbon;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Validation\ValidationException;
+
+class ShiftScheduleService
+{
+    public function shiftsCoveringMoment(Carbon $moment): Collection
+    {
+        $minutes = $moment->hour * 60 + $moment->minute;
+        $today = ShiftDayEnum::fromDate($moment)->value;
+        $yesterday = ShiftDayEnum::fromDate($moment->copy()->subDay())->value;
+
+        return Shift::active()
+            ->where(function ($query) use ($moment, $today, $yesterday) {
+                $query->whereDate('date', $moment->toDateString())
+                    ->orWhereDate('date', $moment->copy()->subDay()->toDateString())
+                    ->orWhere(function ($subQuery) use ($today, $yesterday) {
+                        $subQuery->whereNull('date')->whereIn('day_of_week', [$today, $yesterday]);
+                    });
+            })
+            ->get()
+            ->filter(function (Shift $shift) use ($moment, $minutes) {
+                $start = $this->toMinutes($shift->start_time);
+                $end = $this->toMinutes($shift->end_time);
+
+                if ($end > $start) {
+                    return $this->coversDate($shift, $moment) && $minutes >= $start && $minutes < $end;
+                }
+
+                // overnight shift: covers [start, 24:00) on its day and [00:00, end) on the next day
+                if ($this->coversDate($shift, $moment) && $minutes >= $start) {
+                    return true;
+                }
+
+                return $this->coversDate($shift, $moment->copy()->subDay()) && $minutes < $end;
+            })
+            ->values();
+    }
+
+    public function availableDoctorsAt(Carbon $moment): Collection
+    {
+        $doctorIds = $this->shiftsCoveringMoment($moment)->pluck('user_id')->filter()->unique();
+
+        if ($doctorIds->isEmpty()) {
+            return collect();
+        }
+
+        return User::where('level', UserEnum::Doctor->value)
+            ->whereIn('id', $doctorIds)
+            ->get();
+    }
+
+    public function autoSelectDoctor(Carbon $moment): ?User
+    {
+        $doctorIds = $this->shiftsCoveringMoment($moment)->pluck('user_id')->filter()->unique();
+
+        if ($doctorIds->isEmpty()) {
+            return null;
+        }
+
+        return User::where('level', UserEnum::Doctor->value)
+            ->whereIn('id', $doctorIds)
+            ->withCount(['documents as open_documents_count' => function ($query) {
+                $query->whereIn('status', [
+                    DocumentStatusEnum::Registered->value,
+                    DocumentStatusEnum::InProgress->value,
+                ]);
+            }])
+            ->orderBy('open_documents_count')
+            ->orderBy('id')
+            ->first();
+    }
+
+    public function hasConflict(array $data, ?int $ignoreId = null): bool
+    {
+        if (empty($data['user_id'])) {
+            return false;
+        }
+
+        $candidate = new Shift($data);
+
+        return Shift::active()
+            ->where('user_id', $data['user_id'])
+            ->when($ignoreId, fn ($query) => $query->where('id', '!=', $ignoreId))
+            ->get()
+            ->contains(fn (Shift $existing) => $this->overlaps($existing, $candidate));
+    }
+
+    public function claim(int $shiftId, User $doctor): Shift
+    {
+        return DB::transaction(function () use ($shiftId, $doctor) {
+            $shift = Shift::whereKey($shiftId)->lockForUpdate()->firstOrFail();
+
+            if (!$shift->is_active || $shift->user_id !== null) {
+                throw ValidationException::withMessages([
+                    'shift' => 'این شیفت قابل انتخاب نیست.',
+                ]);
+            }
+
+            $data = array_merge(
+                $shift->only(['day_of_week', 'date', 'start_time', 'end_time']),
+                ['user_id' => $doctor->id]
+            );
+
+            if ($this->hasConflict($data, $shift->id)) {
+                throw ValidationException::withMessages([
+                    'shift' => 'این شیفت با برنامه فعلی شما تداخل دارد.',
+                ]);
+            }
+
+            $shift->update(['user_id' => $doctor->id]);
+
+            return $shift;
+        });
+    }
+
+    public function release(Shift $shift, User $doctor): Shift
+    {
+        if ($shift->user_id !== $doctor->id) {
+            throw ValidationException::withMessages([
+                'shift' => 'شما مجاز به تغییر این شیفت نیستید.',
+            ]);
+        }
+
+        $shift->update(['user_id' => null]);
+
+        return $shift;
+    }
+
+    public function overlaps(Shift $first, Shift $second): bool
+    {
+        $byWeekday = !$first->date || !$second->date;
+
+        foreach ($this->daySegments($first, $byWeekday) as [$dayA, $startA, $endA]) {
+            foreach ($this->daySegments($second, $byWeekday) as [$dayB, $startB, $endB]) {
+                if ($dayA === $dayB && $startA < $endB && $startB < $endA) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    protected function coversDate(Shift $shift, Carbon $date): bool
+    {
+        if ($shift->date) {
+            return $shift->date->isSameDay($date);
+        }
+
+        return $shift->day_of_week === ShiftDayEnum::fromDate($date)->value;
+    }
+
+    protected function daySegments(Shift $shift, bool $byWeekday): array
+    {
+        $start = $this->toMinutes($shift->start_time);
+        $end = $this->toMinutes($shift->end_time);
+
+        if ($shift->date) {
+            $day = $byWeekday ? ShiftDayEnum::fromDate($shift->date)->value : $shift->date->toDateString();
+            $nextDay = $byWeekday
+                ? ShiftDayEnum::fromDate($shift->date->copy()->addDay())->value
+                : $shift->date->copy()->addDay()->toDateString();
+        } else {
+            $day = $shift->day_of_week;
+            $nextDay = $this->nextDay($shift->day_of_week);
+        }
+
+        if ($end > $start) {
+            return [[$day, $start, $end]];
+        }
+
+        return [[$day, $start, 1440], [$nextDay, 0, $end]];
+    }
+
+    protected function nextDay(string $day): string
+    {
+        $days = ShiftDayEnum::values();
+        $index = array_search($day, $days);
+
+        return $days[($index + 1) % count($days)];
+    }
+
+    protected function toMinutes(string $time): int
+    {
+        [$hours, $minutes] = explode(':', $time);
+
+        return ((int) $hours) * 60 + ((int) $minutes);
+    }
+}