<?php

namespace App\Services;

use Illuminate\Support\Facades\Log;
use App\Models\KnowledgePoint;
use App\Models\StudentKnowledgeMastery;
use App\Models\TextbookCatalog;
use App\Models\TextbookChapterKnowledgeRelation;

class DiagnosticChapterService
{
    public function getTextbookKnowledgePointsInOrder(int $textbookId): array
    {
        $chapters = TextbookCatalog::query()
            ->where('textbook_id', $textbookId)
            ->where('node_type', 'chapter')
            ->orderBy('display_no')
            ->orderBy('sort_order')
            ->orderBy('id')
            ->get();

        if ($chapters->isEmpty()) {
            Log::warning('DiagnosticChapterService: 未找到章节节点', [
                'textbook_id' => $textbookId,
            ]);
            return [];
        }

        $orderedCodes = [];
        $seen = [];

        foreach ($chapters as $chapter) {
            $sectionIds = TextbookCatalog::query()
                ->where('parent_id', $chapter->id)
                ->where('node_type', 'section')
                ->orderBy('display_no')
                ->orderBy('sort_order')
                ->orderBy('id')
                ->pluck('id')
                ->toArray();

            if (empty($sectionIds)) {
                continue;
            }

            $kpCodes = TextbookChapterKnowledgeRelation::query()
                ->whereIn('catalog_chapter_id', $sectionIds)
                ->pluck('kp_code')
                ->filter()
                ->unique()
                ->values()
                ->toArray();

            $kpCodes = $this->expandWithChildKnowledgePoints($kpCodes);

            foreach ($kpCodes as $kpCode) {
                if (isset($seen[$kpCode])) {
                    continue;
                }
                $seen[$kpCode] = true;
                $orderedCodes[] = $kpCode;
            }
        }

        Log::info('DiagnosticChapterService: 获取教材知识点顺序列表', [
            'textbook_id' => $textbookId,
            'kp_count' => count($orderedCodes),
        ]);

        return $orderedCodes;
    }

    public function getInitialChapterKnowledgePoints(int $textbookId): array
    {
        $chapter = TextbookCatalog::query()
            ->where('textbook_id', $textbookId)
            ->where('node_type', 'chapter')
            ->orderBy('display_no')
            ->orderBy('sort_order')
            ->orderBy('id')
            ->first();

        if (!$chapter) {
            Log::warning('DiagnosticChapterService: 未找到章节节点', [
                'textbook_id' => $textbookId,
            ]);
            return [];
        }

        $sectionIds = TextbookCatalog::query()
            ->where('parent_id', $chapter->id)
            ->where('node_type', 'section')
            ->orderBy('display_no')
            ->orderBy('sort_order')
            ->orderBy('id')
            ->pluck('id')
            ->toArray();

        if (empty($sectionIds)) {
            Log::warning('DiagnosticChapterService: 章节下未找到section节点', [
                'textbook_id' => $textbookId,
                'chapter_id' => $chapter->id,
            ]);
            return [];
        }

        $kpCodes = TextbookChapterKnowledgeRelation::query()
            ->whereIn('catalog_chapter_id', $sectionIds)
            ->pluck('kp_code')
            ->filter()
            ->unique()
            ->values()
            ->toArray();

        $kpCodes = $this->expandWithChildKnowledgePoints($kpCodes);

        Log::info('DiagnosticChapterService: 获取首章知识点', [
            'textbook_id' => $textbookId,
            'chapter_id' => $chapter->id,
            'section_count' => count($sectionIds),
            'kp_count' => count($kpCodes),
        ]);

        return [
            'chapter_id' => $chapter->id,
            'section_ids' => $sectionIds,
            'kp_codes' => $kpCodes,
        ];
    }

    public function getFirstUnmasteredChapterKnowledgePoints(int $textbookId, int $studentId, float $threshold = 0.9): array
    {
        $chapters = TextbookCatalog::query()
            ->where('textbook_id', $textbookId)
            ->where('node_type', 'chapter')
            ->orderBy('display_no')
            ->orderBy('sort_order')
            ->orderBy('id')
            ->get();

        if ($chapters->isEmpty()) {
            Log::warning('DiagnosticChapterService: 未找到章节节点', [
                'textbook_id' => $textbookId,
            ]);
            return [];
        }

        foreach ($chapters as $chapter) {
            $sectionIds = TextbookCatalog::query()
                ->where('parent_id', $chapter->id)
                ->where('node_type', 'section')
                ->orderBy('display_no')
                ->orderBy('sort_order')
                ->orderBy('id')
                ->pluck('id')
                ->toArray();

            if (empty($sectionIds)) {
                continue;
            }

            $kpCodes = TextbookChapterKnowledgeRelation::query()
                ->whereIn('catalog_chapter_id', $sectionIds)
                ->pluck('kp_code')
                ->filter()
                ->unique()
                ->values()
                ->toArray();

            $kpCodes = $this->expandWithChildKnowledgePoints($kpCodes);

            if (empty($kpCodes)) {
                continue;
            }

            $allMastered = StudentKnowledgeMastery::allAtLeast($studentId, $kpCodes, $threshold);

            Log::info('DiagnosticChapterService: 章节掌握度评估', [
                'student_id' => $studentId,
                'textbook_id' => $textbookId,
                'chapter_id' => $chapter->id,
                'section_count' => count($sectionIds),
                'kp_count' => count($kpCodes),
                'all_mastered' => $allMastered,
                'threshold' => $threshold,
            ]);

            if (!$allMastered) {
                return [
                    'chapter_id' => $chapter->id,
                    'section_ids' => $sectionIds,
                    'kp_codes' => $kpCodes,
                    'all_mastered' => $allMastered,
                ];
            }
        }

        Log::info('DiagnosticChapterService: 所有章节均达到掌握度阈值', [
            'student_id' => $studentId,
            'textbook_id' => $textbookId,
            'threshold' => $threshold,
        ]);

        return [];
    }

    private function expandWithChildKnowledgePoints(array $kpCodes): array
    {
        if (empty($kpCodes)) {
            return [];
        }

        $baseCodes = collect($kpCodes)->filter()->values()->all();
        $children = KnowledgePoint::query()
            ->whereIn('parent_kp_code', $baseCodes)
            ->orderBy('kp_code')
            ->get(['parent_kp_code', 'kp_code']);

        $childrenMap = [];
        foreach ($children as $child) {
            $childrenMap[$child->parent_kp_code][] = $child->kp_code;
        }

        $ordered = [];
        $seen = [];

        foreach ($baseCodes as $kpCode) {
            if (!isset($seen[$kpCode])) {
                $seen[$kpCode] = true;
                $ordered[] = $kpCode;
            }

            foreach ($childrenMap[$kpCode] ?? [] as $childCode) {
                if (isset($seen[$childCode])) {
                    continue;
                }
                $seen[$childCode] = true;
                $ordered[] = $childCode;
            }
        }

        return $ordered;
    }
}