<?php

namespace App\Support;

use App\Models\Business\CourierQuoteChange;
use App\Models\Business\CourierQuoteChangeEvent;
use App\Models\Business\CourierQuoteVersion;
use App\Models\Business\CourierStockQuoteEntry;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

final class CourierQuoteChangeService
{
    public function __construct(private readonly QuoteManagementSnapshot $snapshot)
    {
    }

    public function create(array $data, int $userId): CourierQuoteChange
    {
        if (str_starts_with($data['source_quote_id'], 'STOCK-') && ($data['change_type'] ?? '') !== '存量报价') {
            throw ValidationException::withMessages(['source_quote_id' => '存量报价请先完成首版审核，再从正式报价版本发起变价。']);
        }
        $source = $this->findSourceQuote($data['source_quote_id']);

        return DB::transaction(function () use ($data, $userId, $source): CourierQuoteChange {
            $retrospective = ($data['change_type'] ?? '') !== '存量报价' && $this->isRetrospectiveDate($data['effective_date']);
            $change = CourierQuoteChange::create([
                'company_id' => company_id(),
                'number' => $this->nextChangeNumber(),
                'source_quote_id' => $source['id'],
                'source_sheet_name' => $source['sheet_name'],
                'carrier_name' => $source['company_name'],
                'quote_type' => $source['quote_type'],
                'change_type' => $data['change_type'],
                'status' => CourierQuoteChange::STATUS_DRAFT,
                'effective_date' => $data['effective_date'],
                'end_date' => ($data['end_date'] ?? null) ?: null,
                'is_retrospective' => $retrospective,
                'recalculation_status' => $retrospective
                    ? CourierQuoteChange::RECALCULATION_PENDING
                    : CourierQuoteChange::RECALCULATION_NOT_REQUIRED,
                'recalculation_note' => null,
                'summary' => $data['summary'],
                'created_by' => $userId,
                'quote_payload' => $data['quote_payload'] ?? null,
                'proposed_values_json' => $data['proposed_values_json'] ?? null,
            ]);

            if (! $change->isStockQuote()) {
                $this->replaceItems($change, $data['items'], $source);
            }
            $this->recordEvent($change, 'created', null, CourierQuoteChange::STATUS_DRAFT, '创建报价变更草稿。', $userId, $this->changeDetails($change));

            return $change->load('items', 'events');
        });
    }

    public function update(CourierQuoteChange $change, array $data, int $userId): CourierQuoteChange
    {
        $this->ensureEditableBy($change, $userId);
        $source = $this->findSourceQuote($change->source_quote_id);

        return DB::transaction(function () use ($change, $data, $userId, $source): CourierQuoteChange {
            $from = $change->status;
            $retrospective = ! $change->isStockQuote() && $this->isRetrospectiveDate($data['effective_date']);
            $change->update([
                'change_type' => $data['change_type'],
                'effective_date' => $data['effective_date'],
                'end_date' => $change->isStockQuote() ? (($data['end_date'] ?? null) ?: null) : $change->end_date,
                'is_retrospective' => $retrospective,
                'recalculation_status' => $retrospective
                    ? CourierQuoteChange::RECALCULATION_PENDING
                    : CourierQuoteChange::RECALCULATION_NOT_REQUIRED,
                'recalculation_note' => null,
                'summary' => $data['summary'],
                'status' => CourierQuoteChange::STATUS_DRAFT,
                'quote_payload' => $change->isStockQuote() ? [...$change->quote_payload, 'billing_rules' => $data['billing_rules']] : $change->quote_payload,
            ]);
            if (! $change->isStockQuote()) {
                $this->replaceItems($change, $data['items'], $source);
            }
            $this->recordEvent($change, 'saved', $from, CourierQuoteChange::STATUS_DRAFT, '保存报价变更草稿。', $userId, $this->changeDetails($change));

            return $change->fresh(['items', 'events']);
        });
    }

    public function submit(CourierQuoteChange $change, int $userId): CourierQuoteChange
    {
        $this->ensureEditableBy($change, $userId);

        if (! ($change->isStockQuote() && filled($change->proposed_values_json)) && $change->items()->count() === 0) {
            throw ValidationException::withMessages(['items' => '至少需要一条发生变化的报价明细。']);
        }

        return DB::transaction(function () use ($change, $userId): CourierQuoteChange {
            $from = $change->status;
            $retrospective = ! $change->isStockQuote() && $this->isRetrospectiveDate($change->effective_date);
            $change->update([
                'status' => CourierQuoteChange::STATUS_PENDING_REVIEW,
                'is_retrospective' => $retrospective,
                'recalculation_status' => $retrospective
                    ? CourierQuoteChange::RECALCULATION_PENDING
                    : CourierQuoteChange::RECALCULATION_NOT_REQUIRED,
                'recalculation_note' => null,
                'submitted_by' => $userId,
                'submitted_at' => now(),
            ]);
            $this->recordEvent($change, 'submitted', $from, CourierQuoteChange::STATUS_PENDING_REVIEW, '提交报价变更审核。', $userId, $this->changeDetails($change));

            return $change->fresh(['items', 'events']);
        });
    }

    public function returnForChanges(CourierQuoteChange $change, string $note, int $userId): CourierQuoteChange
    {
        if ($change->status !== CourierQuoteChange::STATUS_PENDING_REVIEW) {
            throw ValidationException::withMessages(['status' => '只有待审核的变更单可以退回。']);
        }

        return DB::transaction(function () use ($change, $note, $userId): CourierQuoteChange {
            $change->update(['status' => CourierQuoteChange::STATUS_RETURNED]);
            $this->recordEvent($change, 'returned', CourierQuoteChange::STATUS_PENDING_REVIEW, CourierQuoteChange::STATUS_RETURNED, $note, $userId);

            return $change->fresh(['items', 'events']);
        });
    }

    public function approve(CourierQuoteChange $change, int $userId, bool $historicalDocumentsConfirmed = false): CourierQuoteChange
    {
        if ($change->status !== CourierQuoteChange::STATUS_PENDING_REVIEW) {
            throw ValidationException::withMessages(['status' => '只有待审核的变更单可以审核通过。']);
        }

        // 测试环境可用 COURIER_ONBOARDING_ALLOW_SAME_REVIEWER=true 放开（一人走完流程），正式环境保持发起人不能自审。
        if ($change->created_by === $userId && ! config('courier_onboarding.allow_same_reviewer')) {
            throw ValidationException::withMessages(['approval' => '发起人不能审核自己提交的报价变更。']);
        }

        $source = $this->findSourceQuote($change->source_quote_id);

        return DB::transaction(function () use ($change, $source, $userId, $historicalDocumentsConfirmed): CourierQuoteChange {
            $change = CourierQuoteChange::query()->lockForUpdate()->findOrFail($change->id);
            if ($change->status !== CourierQuoteChange::STATUS_PENDING_REVIEW) {
                throw ValidationException::withMessages(['status' => '只有待审核的变更单可以审核通过，请刷新状态。']);
            }
            if ($change->isStockQuote()) {
                \App\Models\Common\Company::whereKey(company_id())->lockForUpdate()->firstOrFail();
                $entry = CourierStockQuoteEntry::findOrFail(data_get($change->quote_payload, 'stock_quote_entry_id'));
                app(CourierStockQuoteEntryService::class)->assertPeriod(['code' => $entry->courier_expcode, 'name' => $entry->courier_name], $entry->quote_type, $change->effective_date->toDateString(), $change->end_date?->toDateString(), $entry->id);
            }
            $hasHistoricalFiles = $change->isStockQuote()
                && collect(CourierStockQuoteEntry::query()->findOrFail(data_get($change->quote_payload, 'stock_quote_entry_id'))->files)->contains('kind', 'signed');
            if ($change->isStockQuote() && $historicalDocumentsConfirmed && ! $hasHistoricalFiles) {
                throw ValidationException::withMessages(['stock_signature_verified' => '尚未上传历史签署资料，请补充资料或取消历史资料核验；不影响存量报价审核生效。']);
            }
            $historicalSigned = $hasHistoricalFiles && $historicalDocumentsConfirmed;
            $values = $source['values'];
            $formulas = $source['formulas'];

            // 后台变价 / 重新报价：变价单里已经是完整的新报价矩阵。
            if ($change->hasQuotePayload() && filled($change->proposed_values_json)) {
                $values = json_decode((string) $change->proposed_values_json, true, 512, JSON_THROW_ON_ERROR);
                $formulas = $change->isStockQuote() ? $source['formulas'] : [];
            }

            foreach ($change->hasQuotePayload() ? [] : $change->items as $item) {
                if (! array_key_exists($item->source_row, $values) || ! array_key_exists($item->source_column, $values[$item->source_row])) {
                    throw ValidationException::withMessages(['items' => "报价单元格 {$item->source_cell} 已不存在，请退回重新核对。"]);
                }

                $values[$item->source_row][$item->source_column] = $item->new_amount;
            }

            $importedVersionCount = collect($this->snapshot->load()['quotes'] ?? [])
                ->whereNull('source_change_id')
                ->count();
            $version = CourierQuoteVersion::create([
                'company_id' => company_id(),
                'version_code' => 'PENDING-' . $change->id,
                'source_quote_id' => $source['id'],
                'source_change_id' => $change->id,
                'sheet_name' => $source['sheet_name'],
                'company_name' => $source['company_name'],
                'carrier_name' => $source['company_name'],
                'courier_expcode' => $source['courier_expcode'] ?? null,
                'billing_rules' => $change->isStockQuote() ? data_get($change->quote_payload, 'billing_rules') : ($source['billing_rules'] ?? null),
                'quote_type' => $source['quote_type'],
                'effective_date' => $change->effective_date,
                'end_date' => $change->end_date,
                'source_range' => $source['source_range'],
                'values_json' => json_encode($values, JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR),
                'formulas_json' => json_encode($formulas, JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR),
                'status' => 'approved',
                'signature_status' => $change->isStockQuote() ? ($historicalSigned ? '历史签署资料已归档' : '存量报价，审核生效（无需签章）') : '未签署',
                'created_by' => $change->created_by,
                'approved_by' => $userId,
            ]);
            $version->update([
                'version_code' => sprintf('QB-%03d', $importedVersionCount + $version->id),
            ]);

            $retrospective = ! $change->isStockQuote() && $this->isRetrospectiveDate($change->effective_date);
            $recalculationNote = $retrospective ? $this->retrospectiveBlockReason() : null;
            $change->update([
                'status' => CourierQuoteChange::STATUS_APPROVED,
                'is_retrospective' => $retrospective,
                'recalculation_status' => $retrospective
                    ? CourierQuoteChange::RECALCULATION_BLOCKED
                    : CourierQuoteChange::RECALCULATION_NOT_REQUIRED,
                'recalculation_note' => $recalculationNote,
                'approved_by' => $userId,
                'approved_at' => now(),
                'new_quote_version_id' => $version->id,
            ]);
            $eventNote = "审核通过并生成新版本 {$version->version_code}。";

            if ($retrospective) {
                $eventNote .= ' 该报价为历史生效；补差明细尚未生成，原运费保持不变。';
            }

            $this->recordEvent($change, 'approved', CourierQuoteChange::STATUS_PENDING_REVIEW, CourierQuoteChange::STATUS_APPROVED, $eventNote, $userId, [
                ...$this->changeDetails($change),
                'version_code' => $version->version_code,
                'historical_documents_confirmed' => $historicalSigned,
            ]);

            return $change->fresh(['items', 'events', 'version']);
        });
    }

    public function findSourceQuote(string $id): array
    {
        if (preg_match('/^STOCK-([1-9][0-9]*)$/', $id, $match)) {
            $entry = CourierStockQuoteEntry::query()->where('company_id', company_id())->find($match[1]);
            if ($entry !== null) {
                return $entry->sourceQuote();
            }
        }
        $quote = collect($this->snapshot->load()['quotes'] ?? [])->firstWhere('id', $id);

        if (! is_array($quote)) {
            throw ValidationException::withMessages(['source_quote_id' => '选择的原报价版本不存在或已不可用。']);
        }

        return $quote;
    }

    private function replaceItems(CourierQuoteChange $change, array $items, array $source): void
    {
        $change->items()->withTrashed()->forceDelete();

        foreach (array_values($items) as $position => $item) {
            $row = (int) $item['source_row'];
            $column = (int) $item['source_column'];
            $sourceValue = $source['values'][$row][$column] ?? null;
            $formula = $source['formulas'][$row][$column] ?? null;

            if (is_string($formula) && trim($formula) !== '') {
                throw ValidationException::withMessages(["items.{$position}.source_cell" => "{$item['source_cell']} 是公式单元格，不能直接改价。"]);
            }

            if (! is_numeric($sourceValue)) {
                throw ValidationException::withMessages(["items.{$position}.source_cell" => "{$item['source_cell']} 不是可调整的数值单元格。"]);
            }

            if (abs((float) $sourceValue - (float) $item['original_amount']) > 0.00005) {
                throw ValidationException::withMessages(["items.{$position}.original_amount" => "{$item['source_cell']} 的原价格已经变化，请重新载入后再保存。"]);
            }

            if ((float) $item['new_amount'] < 0) {
                throw ValidationException::withMessages(["items.{$position}.new_amount" => '新价格不能小于 0。']);
            }

            if (round((float) $item['new_amount'], 4) === round((float) $item['original_amount'], 4)) {
                continue;
            }

            $change->items()->create([
                'company_id' => company_id(),
                'position' => $position,
                'source_cell' => strtoupper($item['source_cell']),
                'source_row' => $row,
                'source_column' => $column,
                'region' => $item['region'] ?? null,
                'weight_band' => $item['weight_band'] ?? null,
                'charge_item' => $item['charge_item'] ?? null,
                'original_amount' => number_format((float) $item['original_amount'], 4, '.', ''),
                'new_amount' => number_format((float) $item['new_amount'], 4, '.', ''),
                'unit' => $item['unit'] ?? null,
                'note' => $item['note'] ?? null,
            ]);
        }

        if ($change->items()->count() === 0) {
            throw ValidationException::withMessages(['items' => '至少需要一条原价格与新价格不同的变价明细。']);
        }
    }

    private function ensureEditableBy(CourierQuoteChange $change, int $userId): void
    {
        if (! $change->isEditable()) {
            throw ValidationException::withMessages(['status' => '当前状态不允许继续修改。']);
        }

        if ($change->created_by !== $userId) {
            abort(403, '只有草稿发起人可以修改或提交该变更单。');
        }
    }

    private function recordEvent(CourierQuoteChange $change, string $type, ?string $from, ?string $to, string $note, int $userId, array $details = []): void
    {
        CourierQuoteChangeEvent::create([
            'company_id' => company_id(),
            'quote_change_id' => $change->id,
            'event_type' => $type,
            'from_status' => $from,
            'to_status' => $to,
            'note' => $note,
            'details_json' => $details === [] ? null : json_encode($details, JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR),
            'created_by' => $userId,
        ]);
    }

    private function changeDetails(CourierQuoteChange $change): array
    {
        return [
            ...($change->isStockQuote() ? [
                'stock_quote_entry_id' => data_get($change->quote_payload, 'stock_quote_entry_id'),
                'billing_rules' => data_get($change->quote_payload, 'billing_rules'),
                'files' => collect(CourierStockQuoteEntry::query()->findOrFail(data_get($change->quote_payload, 'stock_quote_entry_id'))->files)
                    ->map(static fn (array $file): array => \Illuminate\Support\Arr::only($file, ['kind', 'name', 'sha256']))->all(),
            ] : []),
            'change_type' => $change->change_type,
            'carrier_name' => $change->carrier_name,
            'effective_date' => $change->effective_date->toDateString(),
            'end_date' => $change->end_date?->toDateString(),
            'is_retrospective' => $change->isRetrospective(),
            'recalculation_status' => $change->recalculation_status,
            'recalculation_note' => $change->recalculation_note,
            'summary' => $change->summary,
            'items' => $change->items()->get()->map(static fn ($item): array => [
                'source_cell' => $item->source_cell,
                'original_amount' => $item->original_amount,
                'new_amount' => $item->new_amount,
                'note' => $item->note,
            ])->all(),
        ];
    }

    private function nextChangeNumber(): string
    {
        $prefix = 'BG-' . now()->format('Ymd') . '-';
        $last = CourierQuoteChange::withTrashed()->where('number', 'like', $prefix . '%')->lockForUpdate()->max('number');
        $sequence = $last ? ((int) substr($last, -3)) + 1 : 1;

        return $prefix . str_pad((string) $sequence, 3, '0', STR_PAD_LEFT);
    }

    private function isRetrospectiveDate(string|Carbon $effectiveDate): bool
    {
        return Carbon::parse($effectiveDate)->startOfDay()->lt(today());
    }

    private function retrospectiveBlockReason(): string
    {
        return '未生成补差明细：当前报价未提供可执行的运费计算方式，历史运费也未记录所用报价版本。补差前需建立逐票原报价版本关联和可验证的报价计算规则；原运费及原始 Excel 保持不变。';
    }

}