<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Models\Document;
use App\Models\Guide;
use App\Models\GuidePage;
use App\Models\GuidePageEdge;
use App\Models\KnowledgeBase;
use App\Services\KnowledgeContextService;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class TerminalApiController extends Controller
{
    public function __construct(
        private KnowledgeContextService $knowledgeService,
    ) {}

    /**
     * GET /api/terminal/config
     * 返回终端配置
     */
    public function config(Request $request): JsonResponse
    {
        $terminal = $request->attributes->get('terminal');
        $terminal->load('station');

        $systemPrompt = $terminal->prompt_template ?? '';

        // 获取终端所属线站的已发布指引数量（含全局指引）
        $guideCount = $this->getTerminalGuides($terminal)->count();

        return response()->json([
            'terminal' => [
                'id' => $terminal->id,
                'terminal_name' => $terminal->name,
                'terminal_code' => $terminal->code,
                'station_name' => $terminal->station?->name,
                'diagram_urls' => collect($terminal->diagram_urls ?? [])->values()->map(fn ($item) => [
                    'title' => $item['title'] ?? '',
                    'url' => $item['url'] ?? '',
                ])->all(),
                'scada_data_url' => $terminal->scada_data_url,
                'scada_tags_url' => $terminal->scada_tags_url,
                'voice_wakeup_enabled' => $terminal->voice_wakeup_enabled,
                'voice_wakeup_word' => $terminal->voice_wakeup_word,
            ],
            'system_prompt' => $systemPrompt,
            'guide_count' => $guideCount,
        ]);
    }

    /**
     * GET /api/knowledge?query=xxx
     * RAG知识搜索（由AI tool_call触发）
     */
    public function knowledge(Request $request): JsonResponse
    {
        $request->validate([
            'query' => 'required|string|max:500',
        ]);

        $terminal = $request->attributes->get('terminal');
        $result = $this->knowledgeService->search($request->input('query'), $terminal);

        return response()->json($result);
    }

    /**
     * GET /api/terminal/guides?category=operation
     * 已发布的指引列表
     */
    public function guides(Request $request): JsonResponse
    {
        $terminal = $request->attributes->get('terminal');
        $query = $this->getTerminalGuides($terminal)->withCount('pages');

        if ($category = $request->input('category')) {
            $query->where('category', $category);
        }

        $guides = $query->orderBy('name')->get()->map(fn(Guide $guide) => [
            'id' => $guide->id,
            'name' => $guide->name,
            'description' => $guide->description,
            'category' => $guide->category,
            'tags' => $guide->tags,
            'page_count' => $guide->pages_count,
        ]);

        return response()->json(['guides' => $guides]);
    }

    /**
     * POST /api/terminal/guides/pages
     * 返回指引页面（状态机格式，每页带 next 指针）
     */
    public function guidePages(Request $request): JsonResponse
    {
        $request->validate([
            'guide_ids' => 'required|array|min:1',
            'guide_ids.*' => 'integer|exists:guides,id',
        ]);

        $terminal = $request->attributes->get('terminal');
        $accessibleIds = $this->getTerminalGuides($terminal)->pluck('guides.id')->toArray();

        $guideIds = collect($request->input('guide_ids'))
            ->intersect($accessibleIds)
            ->values()
            ->toArray();

        $pages = GuidePage::whereIn('guide_id', $guideIds)->get();
        $edges = GuidePageEdge::whereIn('guide_id', $guideIds)
            ->orderBy('from_page_id')
            ->orderBy('sort')
            ->get();

        $edgesByFrom = $edges->groupBy('from_page_id');
        $hasIncoming = $edges->pluck('to_page_id')->unique()->flip();

        $guides = [];
        foreach ($pages->groupBy('guide_id') as $guideId => $guidePages) {
            $entryPage = $guidePages->first(fn($p) => !$hasIncoming->has($p->id));

            $pagesMap = [];
            foreach ($guidePages as $page) {
                $next = $edgesByFrom->get($page->id, collect())
                    ->map(function (GuidePageEdge $e) {
                        $item = ['page_id' => $e->to_page_id];
                        if ($e->label !== null) {
                            $item['label'] = $e->label;
                        }
                        return $item;
                    })->values()->toArray();

                $pagesMap[$page->id] = [
                    'id' => $page->id,
                    'title' => $page->title,
                    'uri' => $page->uri,
                    'next' => $next,
                ];
            }

            $guides[$guideId] = [
                'entry_page_id' => $entryPage?->id,
                'pages' => $pagesMap,
            ];
        }

        return response()->json([
            'guides' => $guides,
        ]);
    }

    /**
     * 获取终端可见的指引（线站关联 + 全局）
     */
    private function getTerminalGuides($terminal)
    {
        $stationId = $terminal->station_id;

        return Guide::published()->where(function ($q) use ($stationId) {
            $q->whereDoesntHave('stations'); // 全局指引
            if ($stationId) {
                $q->orWhereHas('stations', fn($sq) => $sq->where('stations.id', $stationId));
            }
        });
    }

    /**
     * GET /api/terminal/documents/{document}/content
     * 读取文档全文或指定行号区间
     */
    public function documentContent(Request $request, int $documentId): JsonResponse
    {
        $request->validate([
            'start_line' => 'sometimes|integer|min:1',
            'end_line' => 'sometimes|integer|min:1',
        ]);

        $terminal = $request->attributes->get('terminal');

        // Find document and verify access through station → knowledge_base
        $accessibleKbIds = KnowledgeBase::where(function ($q) use ($terminal) {
            $q->whereDoesntHave('stations'); // global knowledge bases
            if ($terminal->station_id) {
                $q->orWhereHas('stations', fn ($sq) => $sq->where('stations.id', $terminal->station_id));
            }
        })->where('status', 'active')->pluck('id');

        $document = Document::where('id', $documentId)
            ->whereIn('knowledge_base_id', $accessibleKbIds)
            ->where('conversion_status', 'completed')
            ->first();

        if (!$document) {
            return response()->json(['error' => 'Document not found'], 404);
        }

        $content = $document->getMarkdownContent();
        if ($content === null) {
            return response()->json(['error' => 'Document content unavailable'], 404);
        }

        $lines = explode("\n", $content);
        $totalLines = count($lines);

        $startLine = $request->integer('start_line', 1);
        $endLine = $request->integer('end_line', min($startLine + 49, $totalLines));
        $endLine = min($endLine, $totalLines);

        if ($startLine > $totalLines) {
            return response()->json([
                'error' => "start_line ({$startLine}) exceeds total lines ({$totalLines})",
            ], 422);
        }

        $slice = array_slice($lines, $startLine - 1, $endLine - $startLine + 1);

        return response()->json([
            'id' => $document->id,
            'title' => $document->title,
            'total_lines' => $totalLines,
            'start_line' => $startLine,
            'end_line' => $endLine,
            'content' => implode("\n", $slice),
        ]);
    }

    /**
     * POST /api/terminal/heartbeat
     * 终端心跳上报
     */
    public function heartbeat(Request $request): JsonResponse
    {
        $terminal = $request->attributes->get('terminal');

        $terminal->update([
            'is_online' => true,
            'last_online_at' => now(),
        ]);

        return response()->json(['status' => 'ok']);
    }
}