<?php

declare(strict_types=1);

namespace App\Models;

use DateTimeImmutable;
use PDO;
use Throwable;

final class CoverageModel extends BaseModel
{
    private const DAY_LABELS = [
        1 => 'Lundi',
        2 => 'Mardi',
        3 => 'Mercredi',
        4 => 'Jeudi',
        5 => 'Vendredi',
    ];

    public function rulesForStructure(int $structureId): array
    {
        $stmt = $this->pdo->prepare(
            "SELECT id_couverture, id_structure, jour_semaine,
                    TIME_FORMAT(heure_debut, '%H:%i') AS heure_debut,
                    TIME_FORMAT(heure_fin, '%H:%i') AS heure_fin,
                    minimum_agents
             FROM structure_couverture_horaire
             WHERE id_structure = :structure_id
             ORDER BY jour_semaine, heure_debut, heure_fin"
        );
        $stmt->execute(['structure_id' => $structureId]);
        return $stmt->fetchAll();
    }

    public function replaceRules(int $structureId, array $rules): void
    {
        try {
            $this->pdo->beginTransaction();

            $delete = $this->pdo->prepare(
                'DELETE FROM structure_couverture_horaire WHERE id_structure = :structure_id'
            );
            $delete->execute(['structure_id' => $structureId]);

            if ($rules !== []) {
                $insert = $this->pdo->prepare(
                    'INSERT INTO structure_couverture_horaire
                        (id_structure, jour_semaine, heure_debut, heure_fin, minimum_agents)
                     VALUES
                        (:structure_id, :jour_semaine, :heure_debut, :heure_fin, :minimum_agents)'
                );

                foreach ($rules as $rule) {
                    $insert->execute([
                        'structure_id' => $structureId,
                        'jour_semaine' => (int) $rule['jour_semaine'],
                        'heure_debut' => $rule['heure_debut'],
                        'heure_fin' => $rule['heure_fin'],
                        'minimum_agents' => (int) $rule['minimum_agents'],
                    ]);
                }
            }

            $this->pdo->commit();
        } catch (Throwable $e) {
            if ($this->pdo->inTransaction()) {
                $this->pdo->rollBack();
            }
            throw $e;
        }
    }

    public function reportForStructure(int $structureId, int $year, int $weekNumber): array
    {
        $rules = $this->rulesForStructure($structureId);
        $weekStart = (new DateTimeImmutable())->setISODate($year, $weekNumber, 1)->setTime(0, 0);
        $weekEnd = $weekStart->modify('+4 days');

        if ($rules === []) {
            return [
                'configured' => false,
                'rules' => [],
                'gaps' => [],
                'validation_warnings' => [],
                'summary' => [
                    'gap_count' => 0,
                    'gap_minutes' => 0,
                    'validation_warning_count' => 0,
                ],
            ];
        }

        $entries = $this->workEntries(
            $structureId,
            $weekStart->format('Y-m-d'),
            $weekEnd->format('Y-m-d')
        );

        $entriesByDate = [];
        foreach ($entries as $entry) {
            $entriesByDate[$entry['date_jour']][] = $entry;
        }

        $gaps = [];
        $validationWarnings = [];

        foreach ($rules as $rule) {
            $dayNumber = (int) $rule['jour_semaine'];
            $date = $weekStart->modify('+' . ($dayNumber - 1) . ' days')->format('Y-m-d');
            $start = $this->timeToMinutes((string) $rule['heure_debut']);
            $end = $this->timeToMinutes((string) $rule['heure_fin']);
            $minimum = (int) $rule['minimum_agents'];

            for ($slotStart = $start; $slotStart < $end; $slotStart += 15) {
                $slotEnd = min($slotStart + 15, $end);
                $plannedAgents = [];
                $validatedAgents = [];

                foreach ($entriesByDate[$date] ?? [] as $entry) {
                    $entryStart = $this->timeToMinutes((string) $entry['heure_debut']);
                    $entryEnd = $this->timeToMinutes((string) $entry['heure_fin']);
                    if ($entryStart >= $slotEnd || $entryEnd <= $slotStart) {
                        continue;
                    }

                    $agentId = (int) $entry['id_agent'];
                    $plannedAgents[$agentId] = true;
                    if ($entry['statut'] === 'VALIDE') {
                        $validatedAgents[$agentId] = true;
                    }
                }

                $plannedCount = count($plannedAgents);
                $validatedCount = count($validatedAgents);
                $base = [
                    'date' => $date,
                    'jour_semaine' => $dayNumber,
                    'jour_libelle' => self::DAY_LABELS[$dayNumber] ?? 'Jour',
                    'heure_debut' => $this->minutesToTime($slotStart),
                    'heure_fin' => $this->minutesToTime($slotEnd),
                    'minimum_agents' => $minimum,
                    'agents_planifies' => $plannedCount,
                    'agents_valides' => $validatedCount,
                ];

                if ($plannedCount < $minimum) {
                    $base['agents_manquants'] = $minimum - $plannedCount;
                    $this->appendMergedInterval($gaps, $base, ['minimum_agents', 'agents_planifies', 'agents_manquants']);
                } elseif ($validatedCount < $minimum) {
                    $base['validations_manquantes'] = $minimum - $validatedCount;
                    $this->appendMergedInterval($validationWarnings, $base, ['minimum_agents', 'agents_valides', 'validations_manquantes']);
                }
            }
        }

        $gapMinutes = 0;
        foreach ($gaps as $gap) {
            $gapMinutes += $this->timeToMinutes($gap['heure_fin']) - $this->timeToMinutes($gap['heure_debut']);
        }

        return [
            'configured' => true,
            'rules' => $rules,
            'gaps' => $gaps,
            'validation_warnings' => $validationWarnings,
            'summary' => [
                'gap_count' => count($gaps),
                'gap_minutes' => $gapMinutes,
                'validation_warning_count' => count($validationWarnings),
            ],
        ];
    }

    private function workEntries(int $structureId, string $dateStart, string $dateEnd): array
    {
        $stmt = $this->pdo->prepare(
            "SELECT p.id_agent, p.statut, c.date_jour,
                    TIME_FORMAT(c.heure_debut, '%H:%i') AS heure_debut,
                    TIME_FORMAT(c.heure_fin, '%H:%i') AS heure_fin
             FROM planning p
             INNER JOIN agent a ON a.id_agent = p.id_agent AND a.actif = TRUE
             INNER JOIN creneau_horaire c ON c.id_planning = p.id_planning
             INNER JOIN motif_planning m ON m.id_motif = c.id_motif
             WHERE p.id_structure = :structure_id
               AND c.date_jour BETWEEN :date_start AND :date_end
               AND m.code = 'TRAVAIL'
             ORDER BY c.date_jour, c.heure_debut, c.heure_fin"
        );
        $stmt->execute([
            'structure_id' => $structureId,
            'date_start' => $dateStart,
            'date_end' => $dateEnd,
        ]);
        return $stmt->fetchAll();
    }

    private function appendMergedInterval(array &$target, array $slot, array $comparisonKeys): void
    {
        $lastIndex = count($target) - 1;
        if ($lastIndex >= 0) {
            $last = $target[$lastIndex];
            $same = $last['date'] === $slot['date'] && $last['heure_fin'] === $slot['heure_debut'];
            foreach ($comparisonKeys as $key) {
                $same = $same && (int) $last[$key] === (int) $slot[$key];
            }
            if ($same) {
                $target[$lastIndex]['heure_fin'] = $slot['heure_fin'];
                return;
            }
        }
        $target[] = $slot;
    }

    private function timeToMinutes(string $time): int
    {
        [$hours, $minutes] = array_map('intval', explode(':', substr($time, 0, 5)));
        return ($hours * 60) + $minutes;
    }

    private function minutesToTime(int $minutes): string
    {
        return sprintf('%02d:%02d', intdiv($minutes, 60), $minutes % 60);
    }
}