<?php

namespace Modules\EcommerceFinance\Services;

/**
 * 科目映射表校验。
 *
 * 三档含义（不是拍脑袋的严重度）：
 *   错误 = 会让程序生成凭证失败，或让账务数字直接错 → 必须改
 *   警告 = 账能做、程序能跑，但口径不对 → 影响扣除、税负、可比性
 *   提示 = 只是建议 → 做账时留意
 *
 * 校验只针对「一笔账单按某条规则生成分录」这一件事，不评价业务口径优劣。
 */
class AccountMappingValidator
{
    public function __construct(private readonly AccountMappingCoa $coa)
    {
    }

    /**
     * @param array<int,array<string,mixed>> $rules
     * @return array{issues:array<int,array<int,array{level:string,code:string,message:string}>>,summary:array<string,int>}
     */
    public function validate(array $rules): array
    {
        $issues = [];
        $dupIndex = [];
        foreach ($rules as $rule) {
            $dupIndex[implode('|', [
                trim((string) ($rule['platform'] ?? '')),
                trim((string) ($rule['item'] ?? '')),
            ])][] = (int) $rule['id'];
        }

        // 同一「平台 + 账单项目」下，用区分条件（业务备注 + 商品名称）分组：
        //   条件相同的两条 = 真重复（提示）；
        //   条件不同的多条 = 按条件区分（正常，不报）。
        $conditionIndex = [];
        foreach ($rules as $rule) {
            $conditionIndex[$this->pairKey($rule)][$this->conditionKey($rule)][] = (int) $rule['id'];
        }

        foreach ($rules as $rule) {
            $id = (int) $rule['id'];
            $list = [];

            $list = array_merge($list, $this->accountIssues($rule, 'dAcct', 'dSub', '借方'));
            $list = array_merge($list, $this->accountIssues($rule, 'cAcct', 'cSub', '贷方'));

            // 方向基准
            $basis = trim((string) ($rule['basis'] ?? ''));
            $category = trim((string) ($rule['category'] ?? ''));

            if ($basis === '') {
                $list[] = $this->issue('错误', 'basis_missing', '没有填方向基准，程序无法判断该照抄还是互换。');
            } elseif (! in_array($basis, AccountMappingStore::BASISES, true)) {
                $list[] = $this->issue('错误', 'basis_invalid', "方向基准「{$basis}」不是有效值，只能是支出基准或收入基准。");
            } elseif ($category !== '' && isset(AccountMappingStore::CATEGORY_BASIS[$category])) {
                $expected = AccountMappingStore::CATEGORY_BASIS[$category];
                if ($expected !== $basis) {
                    $list[] = $this->issue(
                        '警告',
                        'basis_mismatch',
                        "大类「{$category}」按口径应是「{$expected}」，这里填的是「{$basis}」，账单收支与基准不一致时方向会反。"
                    );
                }
            }

            if ($category === '') {
                $list[] = $this->issue('警告', 'category_missing', '没有填大类，方向基准失去参照，也无法按大类筛选。');
            }

            // 票据口径
            $invoice = trim((string) ($rule['invoice'] ?? ''));
            if ($invoice === '') {
                $list[] = $this->issue('提示', 'invoice_missing', '票据口径为空，汇算清缴时不好判断调增项。');
            } elseif (! in_array($invoice, AccountMappingStore::INVOICES, true)) {
                $list[] = $this->issue('提示', 'invoice_unknown', "票据口径「{$invoice}」不在常用取值（0.06 / 不开票 / -）内。");
            }

            // 借贷两边同一个科目
            $d = trim((string) ($rule['dAcct'] ?? ''));
            $c = trim((string) ($rule['cAcct'] ?? ''));
            $ds = trim((string) ($rule['dSub'] ?? ''));
            $cs = trim((string) ($rule['cSub'] ?? ''));
            if ($d !== '' && $d === $c && $ds === $cs) {
                $list[] = $this->issue('警告', 'same_account', '借方和贷方是同一个科目，这笔业务不会有损益影响。');
            }

            // 同平台同项目重复
            $pairKey = trim((string) ($rule['platform'] ?? '')) . '|' . trim((string) ($rule['item'] ?? ''));
            if (count($dupIndex[$pairKey] ?? []) > 1) {
                $sameCondition = array_values(array_diff($conditionIndex[$pairKey][$this->conditionKey($rule)] ?? [], [$id]));

                if ($sameCondition !== []) {
                    $list[] = $this->issue(
                        '提示',
                        'duplicate_pair',
                        '同一平台、同一账单项目、区分条件也相同的第 ' . implode('、', $sameCondition) . ' 条规则属于重复，建议合并。'
                    );
                }

                if (trim((string) ($rule['memo'] ?? '')) === '' && trim((string) ($rule['goods'] ?? '')) === '') {
                    $list[] = $this->issue(
                        '提示',
                        'fallback_rule',
                        '这条没有区分条件，属于兜底规则：只有在同项目下其它带条件的规则都没命中时才会用它。'
                    );
                }
            }

            if ($list !== []) {
                $issues[$id] = $list;
            }
        }

        $errRows = 0;
        $warnRows = 0;
        $errCount = 0;
        $warnCount = 0;
        $tipCount = 0;
        foreach ($issues as $list) {
            $levels = array_column($list, 'level');
            if (in_array('错误', $levels, true)) {
                $errRows++;
            } elseif (in_array('警告', $levels, true)) {
                $warnRows++;
            }
            foreach ($levels as $level) {
                if ($level === '错误') {
                    $errCount++;
                } elseif ($level === '警告') {
                    $warnCount++;
                } else {
                    $tipCount++;
                }
            }
        }

        $total = count($rules);

        return [
            'issues' => $issues,
            'summary' => [
                'total' => $total,
                'error_rows' => $errRows,
                'warning_rows' => $warnRows,
                'ok_rows' => max($total - $errRows - $warnRows, 0),
                'error_count' => $errCount,
                'warning_count' => $warnCount,
                'tip_count' => $tipCount,
            ],
        ];
    }

    /**
     * @return array<int,array{level:string,code:string,message:string}>
     */
    private function accountIssues(array $rule, string $acctField, string $subField, string $side): array
    {
        $list = [];
        $acct = trim((string) ($rule[$acctField] ?? ''));
        $sub = trim((string) ($rule[$subField] ?? ''));

        if ($acct === '') {
            $list[] = $this->issue('错误', 'account_missing', "{$side}科目为空，生成不了分录。");

            return $list;
        }

        $base = $this->coa->toCode($acct);
        if ($base === null) {
            $anywhere = $this->coa->anywhereByName($acct);
            $hint = $anywhere === [] ? '账套里没有这个名称的科目，需要先建科目或改成账套已有的一级科目。'
                : '它只存在于 ' . implode('、', $anywhere) . '，不是一级科目，应放到对应的一级科目下面。';
            $list[] = $this->issue('错误', 'account_unknown', "{$side}科目「{$acct}」在账套里找不到：{$hint}");

            return $list;
        }

        if ($sub === '' || $sub === $acct) {
            return $list;
        }

        $hits = $this->coa->resolve($acct, $sub);
        if (count($hits) === 1) {
            return $list;
        }

        if ($hits === []) {
            $anywhere = $this->coa->anywhereByName($sub);
            $hint = $anywhere === []
                ? '账套里没有这个名称，需要新建，或改用已有明细。'
                : '它在 ' . implode('、', $anywhere) . '，不挂在「' . $acct . '」下面。';
            $list[] = $this->issue('警告', 'sub_unknown', "{$side}二级科目「{$sub}」找不到：{$hint}");

            return $list;
        }

        $list[] = $this->issue(
            '警告',
            'sub_ambiguous',
            "{$side}二级科目「{$sub}」在「{$acct}」下有 " . count($hits) . ' 个（' . implode('、', $hits) . '），程序无法自动选，建议改写为编码。'
        );

        return $list;
    }

    /** @return array{level:string,code:string,message:string} */
    private function issue(string $level, string $code, string $message): array
    {
        return ['level' => $level, 'code' => $code, 'message' => $message];
    }

    /** 平台 + 账单项目 */
    private function pairKey(array $rule): string
    {
        return trim((string) ($rule['platform'] ?? '')) . '|' . trim((string) ($rule['item'] ?? ''));
    }

    /** 区分条件：业务备注关键词 + 商品名称关键词 */
    private function conditionKey(array $rule): string
    {
        return trim((string) ($rule['memo'] ?? '')) . '|' . trim((string) ($rule['goods'] ?? ''));
    }
}