<?php

declare(strict_types=1);

namespace app\common\service\tcm;

/**
 * 复诊到期纯函数计算器（无 DB、无 config() 依赖，可直接单测）。
 *
 *  - computeFacts()：由「最新有效订单 + 处方天数 + 签收/发货时间 + 挂号 + 首次触达」算出快照表事实列（方案 §1.2）；
 *  - deriveState()：由快照行事实列 + today 推导展示状态（方案 §1.3 九态与优先级），列表 / 弹窗 / 主管视图共用；
 *  - escalationLevel()：延迟次数 → 升级等级（方案 §1.4）。
 *
 * 约定：所有日期为 'Y-m-d' 字符串（或 null），时间戳为 int 秒；配置缺项用 defaultConfig() 补齐。
 */
final class RevisitDueCalculator
{
    public const STATE_VISITED = 'visited';
    public const STATE_BOOKED = 'booked';
    public const STATE_MISSED = 'missed';
    public const STATE_CONTACTED = 'contacted';
    public const STATE_OVERDUE = 'overdue';
    public const STATE_WARNING = 'warning';
    public const STATE_PENDING = 'pending';
    public const STATE_NO_DAYS = 'no_days';
    public const STATE_NONE = 'none';

    /** 起算来源：1=签收 2=发货 3=下单 0=无 */
    public const ANCHOR_NONE = 0;
    public const ANCHOR_SIGN = 1;
    public const ANCHOR_SHIP = 2;
    public const ANCHOR_CREATE = 3;

    /** 天数来源：0=缺失（或配置兜底） 1=订单 2=处方 */
    public const DAYS_SRC_NONE = 0;
    public const DAYS_SRC_ORDER = 1;
    public const DAYS_SRC_RX = 2;

    /** 周期状态（与 DiagnosisRevisitDue::CLOSED_* 一致） */
    public const CLOSED_OPEN = 0;
    public const CLOSED_BOOKED = 2;
    public const CLOSED_VISITED = 3;
    public const CLOSED_MANUAL = 4;
    public const CLOSED_INVALID = 5;

    /** 挂号事实状态：0=无 1=已约 3=已面诊 4=过号 */
    public const APPT_NONE = 0;
    public const APPT_BOOKED = 1;
    public const APPT_VISITED = 3;
    public const APPT_MISSED = 4;

    /** 偏移量上限（与 RevisitVisitSlotService::MAX_OFFSET 一致） */
    private const MAX_OFFSET = 20;

    /**
     * 默认配置（与 config/project.php 的 revisit_reach 段同键；此处只含计算相关项）。
     *
     * @return array<string, mixed>
     */
    public static function defaultConfig(): array
    {
        return [
            'anchor_chain' => ['sign', 'ship', 'create'],
            'days_fallback_rx' => true,
            'days_default' => 0,
            'day_buckets' => [14, 21, 28, 30],
            'grace_days' => 0,
            'warn_days' => 3,
            'severe_overdue_days' => 7,
            'appointment_min_gap_days' => 1,
            'limit_er_center' => true,
        ];
    }

    /**
     * 合并默认值并做类型归一（容忍 .env / 配置里写成字符串）。
     *
     * @param array<string, mixed> $cfg
     *
     * @return array<string, mixed>
     */
    public static function normalizeConfig(array $cfg): array
    {
        $out = array_replace(self::defaultConfig(), $cfg);

        $chain = $out['anchor_chain'];
        if (is_string($chain)) {
            $chain = explode(',', $chain);
        }
        if (!is_array($chain)) {
            $chain = ['create'];
        }
        $normChain = [];
        foreach ($chain as $c) {
            $c = strtolower(trim((string) $c));
            if (in_array($c, ['sign', 'ship', 'create'], true) && !in_array($c, $normChain, true)) {
                $normChain[] = $c;
            }
        }
        $out['anchor_chain'] = $normChain;

        $buckets = is_array($out['day_buckets']) ? $out['day_buckets'] : [];
        $out['day_buckets'] = array_values(array_unique(array_filter(array_map('intval', $buckets), static fn (int $v): bool => $v > 0)));

        $out['days_fallback_rx'] = (bool) $out['days_fallback_rx'];
        $out['days_default'] = max(0, (int) $out['days_default']);
        $out['grace_days'] = max(0, (int) $out['grace_days']);
        $out['warn_days'] = max(0, (int) $out['warn_days']);
        $out['appointment_min_gap_days'] = max(0, (int) ($out['appointment_min_gap_days'] ?? 1));
        $out['limit_er_center'] = (bool) $out['limit_er_center'];

        // severe_overdue_days 允许阶梯数组：取最小阈值作为「深红」起点
        $severe = $out['severe_overdue_days'];
        if (is_array($severe)) {
            $vals = array_filter(array_map('intval', $severe), static fn (int $v): bool => $v > 0);
            $severe = $vals !== [] ? min($vals) : 7;
        }
        $out['severe_overdue_days'] = max(0, (int) $severe);

        return $out;
    }

    /**
     * 计算快照事实列。
     *
     * @param array{
     *   diagnosis_id:int, assistant_id:int, patient_name?:string,
     *   latest_order:null|array{id:int, create_time:int, medication_days?:int, prescription_id?:int},
     *   valid_order_count:int, offset:int, rx_usage_days?:int|null,
     *   sign_ts?:int|null, ship_ts?:int|null,
     *   appointments?:list<array{id:int, status:int, appointment_date:string, appointment_time?:string}>,
     *   first_touch_ts?:int|null, total_medication_days?:int, diagnosis_active?:bool
     * } $input
     * @param array<string, mixed> $cfg   revisit_reach 配置（可只传部分键）
     * @param string               $today 'Y-m-d'，用于判定「已约」是否仍在未来
     *
     * @return array{
     *   source_order_id:int, order_create_time:int, valid_order_count:int,
     *   anchor_ts:int, anchor_src:int, medication_days:int, days_src:int, rule_days:int,
     *   total_medication_days:int, current_slot:int, next_slot:int,
     *   first_touch_date:string|null, due_date:string|null,
     *   appointment_state:int, appointment_date:string|null, booked_appointment_id:int, closed_state_auto:int
     * }
     */
    public static function computeFacts(array $input, array $cfg, string $today): array
    {
        $cfg = self::normalizeConfig($cfg);

        $assistantId = (int) ($input['assistant_id'] ?? 0);
        $validCount = max(0, (int) ($input['valid_order_count'] ?? 0));
        $offset = (int) ($input['offset'] ?? 0);
        if ($offset < 0) {
            $offset = 0;
        }
        if ($offset > self::MAX_OFFSET) {
            $offset = self::MAX_OFFSET;
        }
        $currentSlot = $validCount + $offset;
        $firstTouchTs = (int) ($input['first_touch_ts'] ?? 0);
        $diagnosisActive = (bool) ($input['diagnosis_active'] ?? true);

        $order = $input['latest_order'] ?? null;
        if (!is_array($order) || (int) ($order['id'] ?? 0) <= 0) {
            $order = null;
        }

        $facts = [
            'source_order_id' => 0,
            'order_create_time' => 0,
            'valid_order_count' => $validCount,
            'anchor_ts' => 0,
            'anchor_src' => self::ANCHOR_NONE,
            'medication_days' => 0,
            'days_src' => self::DAYS_SRC_NONE,
            'rule_days' => 0,
            'total_medication_days' => max(0, (int) ($input['total_medication_days'] ?? 0)),
            'current_slot' => $currentSlot,
            'next_slot' => $currentSlot + 1,
            'first_touch_date' => $firstTouchTs > 0 ? date('Y-m-d', $firstTouchTs) : null,
            'due_date' => null,
            'appointment_state' => self::APPT_NONE,
            'appointment_date' => null,
            'booked_appointment_id' => 0,
            'closed_state_auto' => self::CLOSED_INVALID,
        ];

        // 锚点订单先于失效判定写入：失效行（无医助/禁用/删除）也记录最新有效订单，
        // 否则列表自愈会因 source_order_id=0 ≠ 最新订单 id 而在每次加载时重复刷新这些行
        $orderCreateTime = $order !== null ? (int) ($order['create_time'] ?? 0) : 0;
        $facts['source_order_id'] = $order !== null ? (int) ($order['id'] ?? 0) : 0;
        $facts['order_create_time'] = $orderCreateTime;

        // 无有效订单 / 无医助 / 诊单删除或禁用 → 失效周期
        if ($order === null || $validCount <= 0 || $assistantId <= 0 || !$diagnosisActive) {
            return $facts;
        }

        // 1. 用药起算锚点：按 anchor_chain 回退（签收 → 发货 → 下单）；链耗尽仍无结果时兜底下单时间
        $signTs = (int) ($input['sign_ts'] ?? 0);
        $shipTs = (int) ($input['ship_ts'] ?? 0);
        foreach ($cfg['anchor_chain'] as $src) {
            if ($src === 'sign' && $signTs > 0) {
                $facts['anchor_ts'] = $signTs;
                $facts['anchor_src'] = self::ANCHOR_SIGN;
                break;
            }
            if ($src === 'ship' && $shipTs > 0) {
                $facts['anchor_ts'] = $shipTs;
                $facts['anchor_src'] = self::ANCHOR_SHIP;
                break;
            }
            if ($src === 'create' && $orderCreateTime > 0) {
                $facts['anchor_ts'] = $orderCreateTime;
                $facts['anchor_src'] = self::ANCHOR_CREATE;
                break;
            }
        }
        if ($facts['anchor_ts'] <= 0 && $orderCreateTime > 0) {
            $facts['anchor_ts'] = $orderCreateTime;
            $facts['anchor_src'] = self::ANCHOR_CREATE;
        }

        // 2. 开药天数：订单 medication_days → 处方 usage_days（已剔系统代开/作废）→ 配置兜底（days_default，src 仍记 0）
        $orderDays = (int) ($order['medication_days'] ?? 0);
        $rxDays = (int) ($input['rx_usage_days'] ?? 0);
        if ($orderDays > 0) {
            $facts['medication_days'] = $orderDays;
            $facts['days_src'] = self::DAYS_SRC_ORDER;
        } elseif ($cfg['days_fallback_rx'] && $rxDays > 0) {
            $facts['medication_days'] = $rxDays;
            $facts['days_src'] = self::DAYS_SRC_RX;
        } elseif ($cfg['days_default'] > 0) {
            $facts['medication_days'] = (int) $cfg['days_default'];
            $facts['days_src'] = self::DAYS_SRC_NONE;
        }

        // 3. 档位：仅当天数恰好命中 day_buckets 才归档（15 天不归 14），只用于筛选/展示
        if ($facts['medication_days'] > 0 && in_array($facts['medication_days'], $cfg['day_buckets'], true)) {
            $facts['rule_days'] = $facts['medication_days'];
        }

        // 4. 预计复诊日 = DATE(anchor_ts) + medication_days + grace_days；缺天数为 null
        if ($facts['anchor_ts'] > 0 && $facts['medication_days'] > 0) {
            $facts['due_date'] = self::addDays(date('Y-m-d', $facts['anchor_ts']), $facts['medication_days'] + (int) $cfg['grace_days']);
        }

        // 5. 最新有效挂号 A*（status ∈ 1,3,4；按 appointment_date, appointment_time, id 取最新）
        //    只认「下单日 + appointment_min_gap_days（默认 1，即次日起）」之后的挂号：
        //    实际流程多为「挂号 → 面诊 → 开方 → 当天下单」，同一天（及更早）的面诊是产生这笔药的那次面诊，
        //    不是这笔药之后的复诊，若计入会把周期立刻关闭、患者到期后永远不被提醒。
        $orderDate = $orderCreateTime > 0 ? date('Y-m-d', $orderCreateTime) : '';
        $minAptDate = $orderDate !== '' ? self::addDays($orderDate, (int) $cfg['appointment_min_gap_days']) : '';
        $best = null;
        $bestKey = '';
        foreach ((array) ($input['appointments'] ?? []) as $apt) {
            if (!is_array($apt)) {
                continue;
            }
            $status = (int) ($apt['status'] ?? 0);
            if (!in_array($status, [self::APPT_BOOKED, self::APPT_VISITED, self::APPT_MISSED], true)) {
                continue;
            }
            $aptDate = substr(trim((string) ($apt['appointment_date'] ?? '')), 0, 10);
            if ($aptDate === '' || ($minAptDate !== '' && $aptDate < $minAptDate)) {
                continue;
            }
            $key = $aptDate . ' ' . self::normalizeTime((string) ($apt['appointment_time'] ?? '')) . ' ' . sprintf('%012d', (int) ($apt['id'] ?? 0));
            if ($best === null || strcmp($key, $bestKey) > 0) {
                $best = $apt;
                $bestKey = $key;
                $best['_date'] = $aptDate;
                $best['_status'] = $status;
            }
        }
        if ($best !== null) {
            $facts['appointment_state'] = (int) $best['_status'];
            $facts['appointment_date'] = (string) $best['_date'];
            $facts['booked_appointment_id'] = (int) ($best['id'] ?? 0);
        }

        // 6. 自动周期状态：已面诊 → 3；已约且日期未过 → 2；其余（无挂号/过号/已约已过期/缺天数）保持进行中 0
        if ($facts['appointment_state'] === self::APPT_VISITED) {
            $facts['closed_state_auto'] = self::CLOSED_VISITED;
        } elseif ($facts['appointment_state'] === self::APPT_BOOKED && $facts['appointment_date'] !== null && $facts['appointment_date'] >= $today) {
            $facts['closed_state_auto'] = self::CLOSED_BOOKED;
        } else {
            $facts['closed_state_auto'] = self::CLOSED_OPEN;
        }

        return $facts;
    }

    /**
     * 由快照行 + today 推导展示状态（方案 §1.3）。
     *
     * 优先级：visited > booked > missed > contacted > overdue > warning > pending > no_days > none。
     * missed 不受 due_date 限制（到期日前挂号并过号同样标红）；人工关闭(closed_state=4) 的行保留事实状态但不深红，文案前缀「已关闭·」。
     *
     * @param array<string, mixed> $row 快照行（含 closed_state/appointment_state/appointment_date/due_date/promised_date/valid_order_count/source_order_id/assistant_id）
     * @param array<string, mixed> $cfg revisit_reach 配置
     *
     * @return array{state:string, state_text:string, days_left:int|null, overdue_days:int|null, severe:int}
     */
    public static function deriveState(array $row, string $today, array $cfg): array
    {
        $cfg = self::normalizeConfig($cfg);
        $warnDays = (int) $cfg['warn_days'];
        $severeDays = (int) $cfg['severe_overdue_days'];

        $closed = (int) ($row['closed_state'] ?? self::CLOSED_OPEN);
        $apptState = (int) ($row['appointment_state'] ?? self::APPT_NONE);
        $apptDate = self::nullableDate($row['appointment_date'] ?? null);
        $dueDate = self::nullableDate($row['due_date'] ?? null);
        $promised = self::nullableDate($row['promised_date'] ?? null);
        $validCount = (int) ($row['valid_order_count'] ?? 0);
        $sourceOrderId = (int) ($row['source_order_id'] ?? 0);
        $assistantId = (int) ($row['assistant_id'] ?? 0);

        $none = ['state' => self::STATE_NONE, 'state_text' => '', 'days_left' => null, 'overdue_days' => null, 'severe' => 0];
        if ($validCount <= 0 || $sourceOrderId <= 0 || $assistantId <= 0 || $closed === self::CLOSED_INVALID) {
            return $none;
        }

        $daysLeft = $dueDate !== null ? self::dayDiff($today, $dueDate) : null;
        $overdueDays = $daysLeft !== null ? max(0, -$daysLeft) : null;
        $severe = ($overdueDays !== null && $severeDays > 0 && $overdueDays >= $severeDays) ? 1 : 0;

        $state = self::STATE_NONE;
        $text = '';
        if ($apptState === self::APPT_VISITED) {
            $state = self::STATE_VISITED;
            $text = '已面诊' . self::mdSuffix($apptDate);
            $severe = 0;
        } elseif ($apptState === self::APPT_BOOKED && ($apptDate === null || $apptDate >= $today)) {
            $state = self::STATE_BOOKED;
            $text = '已约' . self::mdSuffix($apptDate);
            $severe = 0;
        } elseif ($apptState === self::APPT_MISSED || ($apptState === self::APPT_BOOKED && $apptDate !== null && $apptDate < $today)) {
            $state = self::STATE_MISSED;
            $text = '过号' . self::mdSuffix($apptDate);
        } elseif ($promised !== null && $promised >= $today) {
            $state = self::STATE_CONTACTED;
            $text = '已联系·约 ' . substr($promised, 5);
            $severe = 0;
        } elseif ($dueDate === null || $daysLeft === null) {
            $state = self::STATE_NO_DAYS;
            $text = '缺开药天数';
            $severe = 0;
        } elseif ($daysLeft <= 0) {
            $state = self::STATE_OVERDUE;
            $text = $overdueDays === 0 ? '今日应挂号' : '超期 ' . $overdueDays . ' 天';
        } elseif ($daysLeft <= $warnDays) {
            $state = self::STATE_WARNING;
            $text = '剩 ' . $daysLeft . ' 天';
            $severe = 0;
        } else {
            $state = self::STATE_PENDING;
            $text = '剩 ' . $daysLeft . ' 天';
            $severe = 0;
        }

        if ($closed === self::CLOSED_MANUAL && in_array($state, [self::STATE_MISSED, self::STATE_OVERDUE, self::STATE_WARNING, self::STATE_PENDING, self::STATE_NO_DAYS], true)) {
            $text = '已关闭·' . $text;
            $severe = 0;
        }

        return [
            'state' => $state,
            'state_text' => $text,
            'days_left' => $daysLeft,
            'overdue_days' => $overdueDays,
            'severe' => $severe,
        ];
    }

    /**
     * 延迟次数 → 升级等级：0→0，1~2→1，3~4→2，≥5→3（方案 §1.4）。
     */
    public static function escalationLevel(int $snoozeCount): int
    {
        if ($snoozeCount <= 0) {
            return 0;
        }
        if ($snoozeCount <= 2) {
            return 1;
        }
        if ($snoozeCount <= 4) {
            return 2;
        }

        return 3;
    }

    /**
     * 两个 'Y-m-d' 日期的天数差：to − from（负数表示 to 早于 from）；任一非法返回 0。
     */
    public static function dayDiff(string $from, string $to): int
    {
        $a = \DateTimeImmutable::createFromFormat('!Y-m-d', substr(trim($from), 0, 10));
        $b = \DateTimeImmutable::createFromFormat('!Y-m-d', substr(trim($to), 0, 10));
        if ($a === false || $b === false) {
            return 0;
        }
        $diff = $a->diff($b);

        return (int) $diff->days * ($diff->invert === 1 ? -1 : 1);
    }

    /**
     * 'Y-m-d' 加 N 天（N 可为负）；非法日期原样返回。
     */
    public static function addDays(string $date, int $days): string
    {
        $d = \DateTimeImmutable::createFromFormat('!Y-m-d', substr(trim($date), 0, 10));
        if ($d === false) {
            return $date;
        }

        return $d->modify(sprintf('%+d days', $days))->format('Y-m-d');
    }

    /**
     * 挂号时间归一：空串/NULL → '00:00:00'，'HH:MM' → 'HH:MM:00'（用于字符串排序）。
     */
    private static function normalizeTime(string $time): string
    {
        $t = trim($time);
        if ($t === '' || $t === '0' || $t === '00:00') {
            return '00:00:00';
        }
        if (preg_match('/^\d{1,2}:\d{2}$/', $t) === 1) {
            $t .= ':00';
        }
        if (preg_match('/^(\d{1,2}):(\d{2}):(\d{2})$/', $t, $m) === 1) {
            return sprintf('%02d:%02d:%02d', (int) $m[1], (int) $m[2], (int) $m[3]);
        }

        return $t;
    }

    /**
     * 日期列归一：空串 / '0000-00-00' / null → null，其余截取前 10 位。
     */
    private static function nullableDate(mixed $value): ?string
    {
        if ($value === null) {
            return null;
        }
        $s = substr(trim((string) $value), 0, 10);
        if ($s === '' || $s === '0000-00-00') {
            return null;
        }

        return $s;
    }

    /** 'Y-m-d' → ' MM-DD'（null 返回空串），用于 chip 文案 */
    private static function mdSuffix(?string $date): string
    {
        return $date !== null ? ' ' . substr($date, 5) : '';
    }
}