<?php

namespace App\Http\Controllers\api;

use App\Http\Controllers\Controller;
use App\Models\Art;
use App\Models\Book;
use App\Models\Branch;
use App\Models\BylawDocument;
use App\Models\Chapter;
use App\Models\Division;
use App\Models\Gate;
use App\Models\JudicialPrecedent;
use App\Models\Law;
use App\Models\LegalOpinion;
use App\Models\Part;
use App\Models\Section;
use App\Models\Volum;
use App\Traits\BaseApiResponse;
use Illuminate\Http\Request;
use Illuminate\Pagination\LengthAwarePaginator;

class GlobalSearchApiController extends Controller
{
    use BaseApiResponse;

    /**
     * Massive Search across ALL data types
     */
    public function search(Request $request)
    {
        $request->validate([
            'search'   => 'nullable|string',
            'per_page' => 'nullable|integer|min:1|max:100',
            'page'     => 'nullable|integer|min:1',
        ]);

        $searchTerm = $request->input('search');
        $perPage = min(max((int) $request->input('per_page', 15), 10), 100);
        $page = (int) $request->input('page', 1);

        $results = collect();

        if (!empty($searchTerm)) {
            $limitPerTable = 100; // Performance safeguard

            // 1. Search Bylaw Documents
            $bylaws = BylawDocument::with(['category', 'approvalAuthority', 'promulgationAuthority'])
                ->where('is_published', true)
                ->where(function ($q) use ($searchTerm) {
                    $q->where('title', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('description', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('promulgation_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('official_gazette_number', 'LIKE', "%{$searchTerm}%");
                })->take($limitPerTable)->get()->map(function($item) {
                    $formatted = $this->formatBylaw($item);
                    $formatted['type'] = 'bylaw';
                    return $formatted;
                });
            $results = $results->merge($bylaws);

            // 2. Search Judicial Precedents
            $judicials = JudicialPrecedent::with('category')
                ->where(function ($q) use ($searchTerm) {
                    $q->where('ruling_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('subject', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('full_text', 'LIKE', "%{$searchTerm}%");
                })->take($limitPerTable)->get()->map(function($item) {
                    $formatted = $this->formatJudicial($item);
                    $formatted['type'] = 'judicial_precedent';
                    return $formatted;
                });
            $results = $results->merge($judicials);

            // 3. Search Legal Opinions
            $opinions = LegalOpinion::with('category')
                ->where(function ($q) use ($searchTerm) {
                    $q->where('opinion_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('subject', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('full_text', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('issuing_authority', 'LIKE', "%{$searchTerm}%");
                })->take($limitPerTable)->get()->map(function($item) {
                    $formatted = $this->formatOpinion($item);
                    $formatted['type'] = 'legal_opinion';
                    return $formatted;
                });
            $results = $results->merge($opinions);

            // 4. Search Arts (Explicitly separated for eager loading & performance)
            $arts = Art::with(['law.category'])
                ->where('title', 'LIKE', "%{$searchTerm}%")
                ->orWhere('text', 'LIKE', "%{$searchTerm}%")
                ->take($limitPerTable)->get()->map(function($item) use ($searchTerm) {
                    $formatted = $this->formatArt($item, $searchTerm, Art::class);
                    $formatted['type'] = 'art';
                    return $formatted;
                });
            $results = $results->merge($arts);

            // 5. Search Laws and Structural Models
            $structuralModels = [
                Law::class, Volum::class, Book::class, Division::class,
                Section::class, Chapter::class, Part::class, Gate::class,
                Branch::class
            ];

            foreach ($structuralModels as $modelClass) {
                $query = $modelClass::query();
                $modelInstance = new $modelClass;
                $table = $modelInstance->getTable();

                $query->where('title', 'LIKE', "%{$searchTerm}%");

                $items = $query->take($limitPerTable)->get()->map(function($item) use ($modelClass, $table) {
                    $formatted = $this->formatStructure($item, $modelClass);
                    $formatted['type'] = ($table === 'section') ? 'sections' : $table;
                    return $formatted;
                });

                $results = $results->merge($items);
            }
        }

        // --- Execute Manual Pagination on the Combined Collection ---
        $total = $results->count();
        // Slice the array for the exact page requested
        $paginatedItems = $results->forPage($page, $perPage)->values();

        // Build a proper Laravel paginator object so the response metadata remains identical
        $paginator = new LengthAwarePaginator(
            $paginatedItems,
            $total,
            $perPage,
            $page,
            ['path' => $request->url(), 'query' => $request->query()]
        );

        $responseData = [
            'items'        => $paginator->items(),
            'current_page' => $paginator->currentPage(),
            'last_page'    => $paginator->lastPage(),
            'per_page'     => $paginator->perPage(),
            'total'        => $paginator->total(),
        ];

        return $this->success($responseData, 'Success', 'Global Search Results Fetched');
    }

    /**
     * Top-level fast search for quick dropdown UI elements
     */
    public function fast_search(Request $request)
    {
        $searchTerm = $request->input('search');
        $results = collect();
        $totalCount = 0;

        // Take a max of 3 from each table so the quick-search array doesn't become too heavy
        $limitPerTable = 3;

        if (!empty($searchTerm)) {

            // 1. Bylaw Documents
            $bylawQuery = BylawDocument::with(['category', 'approvalAuthority', 'promulgationAuthority'])
                ->where('is_published', true)
                ->where(function ($q) use ($searchTerm) {
                    $q->where('title', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('description', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('promulgation_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('official_gazette_number', 'LIKE', "%{$searchTerm}%");
                });
            $totalCount += $bylawQuery->count();
            $bylaws = $bylawQuery->take($limitPerTable)->get()->map(function($item) {
                $formatted = $this->formatBylaw($item);
                $formatted['type'] = 'bylaw';
                return $formatted;
            });
            $results = $results->merge($bylaws);

            // 2. Judicial Precedents
            $judicialQuery = JudicialPrecedent::with('category')
                ->where(function ($q) use ($searchTerm) {
                    $q->where('ruling_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('subject', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('full_text', 'LIKE', "%{$searchTerm}%");
                });
            $totalCount += $judicialQuery->count();
            $judicials = $judicialQuery->take($limitPerTable)->get()->map(function($item) {
                $formatted = $this->formatJudicial($item);
                $formatted['type'] = 'judicial_precedent';
                return $formatted;
            });
            $results = $results->merge($judicials);

            // 3. Legal Opinions
            $opinionQuery = LegalOpinion::with('category')
                ->where(function ($q) use ($searchTerm) {
                    $q->where('opinion_number', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('subject', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('full_text', 'LIKE', "%{$searchTerm}%")
                        ->orWhere('issuing_authority', 'LIKE', "%{$searchTerm}%");
                });
            $totalCount += $opinionQuery->count();
            $opinions = $opinionQuery->take($limitPerTable)->get()->map(function($item) {
                $formatted = $this->formatOpinion($item);
                $formatted['type'] = 'legal_opinion';
                return $formatted;
            });
            $results = $results->merge($opinions);

            // 4. Search Arts
            $artQuery = Art::with(['law.category'])
                ->where('title', 'LIKE', "%{$searchTerm}%")
                ->orWhere('text', 'LIKE', "%{$searchTerm}%");
            $totalCount += $artQuery->count();
            $arts = $artQuery->take($limitPerTable)->get()->map(function($item) use ($searchTerm) {
                $formatted = $this->formatArt($item, $searchTerm, Art::class);
                $formatted['type'] = 'art';
                return $formatted;
            });
            $results = $results->merge($arts);

            // 5. Structural Models
            $structuralModels = [
                Law::class, Volum::class, Book::class, Division::class,
                Section::class, Chapter::class, Part::class, Gate::class,
                Branch::class
            ];

            foreach ($structuralModels as $modelClass) {
                $query = $modelClass::query();
                $modelInstance = new $modelClass;
                $table = $modelInstance->getTable();

                $query->where('title', 'LIKE', "%{$searchTerm}%");

                $totalCount += $query->count();

                // Only append items if we haven't reached ~15 fast search items yet
                if ($results->count() < 15) {
                    $items = $query->take($limitPerTable)->get()->map(function($item) use ($modelClass, $table) {
                        $formatted = $this->formatStructure($item, $modelClass);
                        $formatted['type'] = ($table === 'section') ? 'sections' : $table;
                        return $formatted;
                    });
                    $results = $results->merge($items);
                }
            }
        }

        return $this->success([
            // Return top 15 matches max for dropdown
            'items' => $results->take(15)->values(),
            'count' => $totalCount
        ], 'Success', 'Global Fast Search Results');
    }

    /* -----------------------------------------------------------------
     * FORMATTING HELPERS
     * ----------------------------------------------------------------- */

    private function isLockedForCurrentUserGeneric($item): bool
    {
        return ! auth()->user()->isSubscriber() && (bool) ($item->is_locked ?? false);
    }

    private function formatBylaw($item)
    {
        $isLocked = $this->isLockedForCurrentUserGeneric($item);

        return [
            'id'                        => $item->id,
            'title'                     => $item->title,
            'category_name'             => optional($item->category)->name,
            'approval_authority_name'   => optional($item->approvalAuthority)->name,
            'approval_date'             => $item->approval_date,
            'promulgation_number'       => $item->promulgation_number,
            'description'               => $isLocked ? null : $item->description,
            'is_locked'                 => $isLocked,
        ];
    }

    private function formatJudicial($item)
    {
        $isLocked = $this->isLockedForCurrentUserGeneric($item);

        return [
            'id'                => $item->id,
            'title'             => $item->subject,
            'ruling_number'     => $item->ruling_number,
            'ruling_date'       => $item->ruling_date,
            'text'              => $isLocked ? null : $item->full_text,
            'issuing_authority' => $item->issuing_authority,
            'category_name'     => optional($item->category)->name,
            'is_locked'         => $isLocked,
        ];
    }

    private function formatOpinion($item)
    {
        $isLocked = $this->isLockedForCurrentUserGeneric($item);

        return [
            'id'                => $item->id,
            'title'             => $item->subject,
            'opinion_number'    => $item->opinion_number,
            'opinion_date'      => $item->opinion_date,
            'text'              => $isLocked ? null : $item->full_text,
            'issuing_authority' => $item->issuing_authority,
            'category_name'     => optional($item->category)->name,
            'is_locked'         => $isLocked,
        ];
    }

    private function formatArt($item, $searchTerm, $modelClass)
    {
        // Use eager loaded relation if available to prevent N+1 queries, otherwise fallback to find
        $law = $item->law ?? Law::find($item->law_id);
        $isLocked = ! auth()->user()->isSubscriber() && (bool) $law?->is_locked;

        $text = $item->text ?? '';
        $searchQuoted = preg_quote($searchTerm, '/');
        if (!empty($text) && preg_match('/\b(.{0,50})\b('.$searchQuoted.')\b(.{0,50})\b/i', $text, $matches)) {
            $context = trim($matches[1] ?? '') . ' ' . $matches[2] . ' ' . trim($matches[3] ?? '');
        } else {
            $context = $text;
        }

        return [
            'id'          => $item->id,
            'title'       => $item->title,
            'text'        => $isLocked ? null : $context,
            'is_locked'   => $isLocked,
            'route'       => array_values($this->route($modelClass, $item)),
            'category'    => optional($law->category)->name,
            'law'         => $law?->title,
            'count_art'   => $law?->arts?->count() ?? 0,
            'count_volums'=> $law?->volums?->count() ?? 0,
            'price'       => $law?->price,
            'image'       => $law?->image,
        ];
    }

    private function formatStructure($item, $modelClass)
    {
        $law = Law::find($item?->law_id ?? $item->id);
        $isLocked = ! auth()->user()->isSubscriber() && (bool) $law?->is_locked;

        $payload = [
            'id'        => $item->id,
            'title'     => $item->title,
            'number'    => $item->number,
            'is_locked' => $isLocked,
            'route'     => array_values($this->route($modelClass, $item)),
            'law'       => $law?->title ?? '',
        ];

        if ((new $modelClass)->getTable() == 'laws') {
            $payload['category'] = optional($law?->category)?->name ?? '';
            $payload['image'] = $law?->image;
        }

        return $payload;
    }

    private function route($modelClass, $query)
    {
        if ((new $modelClass)->getTable() == 'art') {
            $route = array_filter([
                Law::find($query->law_id)?->title,
                Volum::find($query->volum_id)?->title,
                Book::find($query->book_id)?->title,
                Division::find($query->division_id)?->title,
                Section::find($query->section_id)?->title,
                Chapter::find($query->chapter_id)?->title,
                Part::find($query->part_id)?->title,
                Gate::find($query->gate_id)?->title,
                Branch::find($query->branch_id)?->title,
            ]);
            return array_values($route);
        }

        if ((new $modelClass)->getTable() == 'laws') {
            return array_values(array_filter([Law::find($query->id)?->title]));
        }

        return [];
    }
}