<?php

namespace App\Util;

use App\Models\Programs;
use App\Models\ProgramVideos;
use App\Models\VideoOcrRecords;
use App\Models\VideoParts;
use Carbon\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Storage;
use InvalidArgumentException;

class VideoOcrUtil
{
    // 紧凑日期时间：20190731_1945 / 20250102_200304 / 20200227-0436 / bl20241218_202612-弹幕版
    const PATTERN_COMPACT = "/(?<!\d)(\d{4})(\d{2})(\d{2})[-_](\d{2})(\d{2})(\d{2})?(?!\d)/";
    // 分隔日期时间：永恒de草薙_2025-01-02_20-03-45
    const PATTERN_DASHED = "/(?<!\d)(\d{4})-(\d{1,2})-(\d{1,2})_(\d{1,2})-(\d{1,2})(?:-(\d{1,2}))?(?!\d)/";
    // 直播标记格式：[2024-01-02].[20_03] / [2024-01-02].[20_03_45]
    const PATTERN_BRACKET = "/\[(\d{4})-(\d{1,2})-(\d{1,2})\]\.\[(\d{1,2})_(\d{1,2})(?:_(\d{1,2}))?\]/";

    /**
     * 从文件名或分P标题解析录制开始时间，覆盖录制文件与 B站分P 的全部已知命名格式。
     * 无法解析或时间非法时返回 null。
     */
    public static function parse_recording_time(?string $name): ?Carbon
    {
        if (!$name) {
            return null;
        }
        foreach ([static::PATTERN_COMPACT, static::PATTERN_DASHED, static::PATTERN_BRACKET] as $pattern) {
            if (!preg_match($pattern, $name, $m)) {
                continue;
            }
            [$year, $month, $day, $hour, $minute] = [(int)$m[1], (int)$m[2], (int)$m[3], (int)$m[4], (int)$m[5]];
            $second = isset($m[6]) && $m[6] !== "" ? (int)$m[6] : 0;
            if (!checkdate($month, $day, $year) || $hour > 23 || $minute > 59 || $second > 59) {
                continue;
            }
            return Carbon::create($year, $month, $day, $hour, $minute, $second);
        }
        return null;
    }

    /**
     * 从 OCR jsonl 文件名解析录制开始时间（去 result_ 前缀与扩展名）。
     */
    public static function parse_jsonl_filename(string $filename): ?Carbon
    {
        $stem = basename($filename);
        $stem = preg_replace("/\.jsonl$/i", "", $stem);
        $stem = preg_replace("/^result_/i", "", $stem);
        return static::parse_recording_time($stem);
    }

    /**
     * 按录制时间匹配分P（精确到分钟，容忍秒级偏差），返回匹配的 VideoParts 集合（0~N 个）。
     */
    public static function match_parts(Carbon $recordedAt): Collection
    {
        $candidates = VideoParts::query()
            ->where("title", "like", "%" . $recordedAt->format("Ymd") . "%")
            ->orWhere("title", "like", "%" . $recordedAt->format("Y-m-d") . "%")
            ->get();
        $target = $recordedAt->format("Y-m-d H:i");
        return $candidates->filter(function (VideoParts $part) use ($target) {
            $partTime = static::parse_recording_time($part->title);
            return $partTime !== null && $partTime->format("Y-m-d H:i") === $target;
        })->values();
    }

    /**
     * 解析 OCR jsonl 文件内容为记录数组，供 import_records 使用。
     * 格式非法时抛 InvalidArgumentException。
     */
    public static function parse_jsonl_records(string $path): array
    {
        $handle = fopen($path, "r");
        if ($handle === false) {
            throw new InvalidArgumentException("无法打开文件：{$path}");
        }
        $records = [];
        $lineNo = 0;
        try {
            while (($line = fgets($handle)) !== false) {
                $lineNo++;
                $line = trim($line);
                if ($line === "") {
                    continue;
                }
                $row = json_decode($line, true);
                if (!is_array($row) || !isset($row["ts"]) || !isset($row["lines"]) || !is_array($row["lines"])) {
                    throw new InvalidArgumentException("第 {$lineNo} 行格式非法");
                }
                $texts = [];
                foreach ($row["lines"] as $ocrLine) {
                    $text = trim($ocrLine["text"] ?? "");
                    if ($text !== "") {
                        $texts[] = $text;
                    }
                }
                $records[] = [
                    "frame" => (int)($row["frame"] ?? 0),
                    "ts" => (float)$row["ts"],
                    "ocr_lines" => json_encode($row["lines"], JSON_UNESCAPED_UNICODE),
                    "plain_text" => implode("\n", $texts),
                ];
            }
        } finally {
            fclose($handle);
        }
        if (sizeof($records) === 0) {
            throw new InvalidArgumentException("文件无有效 OCR 记录");
        }
        return $records;
    }

    /**
     * 导入 OCR 记录：按 (video_bvid, part_num) 事务内整删整插，返回导入条数。
     */
    public static function import_records(string $bvid, int $partNum, array $records): int
    {
        $now = time();
        foreach ($records as &$record) {
            $record["video_bvid"] = $bvid;
            $record["part_num"] = $partNum;
            $record["created_at"] = $now;
            unset($record);
        }
        DB::transaction(function () use ($bvid, $partNum, $records) {
            VideoOcrRecords::query()->where("video_bvid", "=", $bvid)->where("part_num", "=", $partNum)->delete();
            foreach (array_chunk($records, 500) as $chunk) {
                VideoOcrRecords::insert($chunk);
            }
        });
        return sizeof($records);
    }

    /**
     * 将指定分P的全量 OCR 记录生成紧凑 JSON 覆盖上传 CDN（固定路径，无版本化），返回访问 URL。
     * 格式：{"bvid","part","space":[w,h],"recs":[[ts,[[x1,y1,x2,y2,text],...]],...]}，recs 按 ts 升序。
     * space 为实际识别区域：全部框最大坐标向上取整到 16 的倍数（NV12 对齐）。
     */
    public static function export_to_cdn(string $bvid, int $partNum): string
    {
        $records = VideoOcrRecords::query()
            ->where("video_bvid", "=", $bvid)->where("part_num", "=", $partNum)
            ->orderBy("ts")->get();
        if ($records->isEmpty()) {
            throw new InvalidArgumentException("该分P无 OCR 记录：{$bvid} P{$partNum}");
        }
        $maxX = 0;
        $maxY = 0;
        $recs = [];
        foreach ($records as $record) {
            $lines = [];
            foreach ($record->ocr_lines as $line) {
                $box = $line["box"];
                $maxX = max($maxX, $box[2]);
                $maxY = max($maxY, $box[3]);
                $lines[] = [$box[0], $box[1], $box[2], $box[3], $line["text"]];
            }
            $recs[] = [$record->ts, $lines];
        }
        $space = [max(16, (int)(ceil($maxX / 16) * 16)), max(16, (int)(ceil($maxY / 16) * 16))];
        $path = static::cdn_path($bvid, $partNum);
        Storage::put($path, json_encode([
            "bvid" => $bvid,
            "part" => $partNum,
            "space" => $space,
            "recs" => $recs,
        ], JSON_UNESCAPED_UNICODE));
        return Storage::url($path);
    }

    /**
     * 取分P 内指定时间之前最近的一帧 OCR，返回 ["ts"=>秒, "lines"=>[[x1,y1,x2,y2,text],...]]。
     * $time 支持 "H:i:s"（小时可超 24）或秒数；无法解析或无匹配记录时返回 null。
     */
    public static function find_frame_at(string $bvid, int $partNum, $time): ?array
    {
        $seconds = static::time_to_seconds($time);
        if ($seconds === null) {
            return null;
        }
        $record = VideoOcrRecords::query()
            ->where("video_bvid", "=", $bvid)->where("part_num", "=", $partNum)
            ->where("ts", "<=", $seconds)->orderByDesc("ts")->first();
        if ($record === null) {
            return null;
        }
        return [
            "ts" => $record->ts,
            "lines" => array_map(
                fn(array $line) => [$line["box"][0], $line["box"][1], $line["box"][2], $line["box"][3], $line["text"]],
                $record->ocr_lines
            ),
        ];
    }

    /**
     * 建设页 OCR 面板所需的片段元数据（轻量；帧级重数据由前端按返回的 CDN URL 直接拉取）。
     * 每个 pivot：id/label/bvid/起止分P与秒/urls（片段范围内有 OCR 的分P → CDN 全量 JSON URL）。
     * 起止时间未填时对应 sec 为 null（前端不做该侧 in_range 裁剪）。
     */
    public static function panel_pivots(Programs $program): array
    {
        $pivots = $program->video_pivots;
        if ($pivots->isEmpty()) {
            return [];
        }
        $bvids = $pivots->pluck("video_bvid")->unique()->all();
        $ocrParts = VideoOcrRecords::query()->whereIn("video_bvid", $bvids)
            ->select("video_bvid", "part_num")->distinct()->get()
            ->groupBy("video_bvid")->map(fn($rows) => $rows->pluck("part_num")->map(fn($n) => (int)$n)->all())->all();
        return $pivots->map(function (ProgramVideos $pivot) use ($ocrParts) {
            $startPart = (int)$pivot->start_part;
            $stopPart = (int)$pivot->stop_part;
            $urls = [];
            foreach (($ocrParts[$pivot->video_bvid] ?? []) as $partNum) {
                if ($partNum >= $startPart && $partNum <= $stopPart) {
                    $urls[$partNum] = Storage::url(static::cdn_path($pivot->video_bvid, $partNum));
                }
            }
            return [
                "id" => $pivot->id,
                "label" => "{$pivot->video_bvid} P{$pivot->start_part} {$pivot->start_time} → P{$pivot->stop_part} {$pivot->stop_time}",
                "bvid" => $pivot->video_bvid,
                "start_part" => $startPart,
                "start_sec" => $pivot->start_sec === "" ? null : $pivot->start_sec,
                "stop_part" => $stopPart,
                "stop_sec" => $pivot->stop_sec === "" ? null : $pivot->stop_sec,
                "urls" => $urls,
            ];
        })->values()->all();
    }

    private static function time_to_seconds($time): ?float
    {
        if (is_numeric($time)) {
            return (float)$time;
        }
        if (is_string($time) && preg_match("/^(\d+):(\d{1,2}):(\d{1,2})(\.\d+)?$/", $time, $m)) {
            return (int)$m[1] * 3600 + (int)$m[2] * 60 + (int)$m[3] + (float)($m[4] ?? 0);
        }
        return null;
    }

    /**
     * 分P OCR 结果的 CDN 对象路径（固定、可推导，覆盖上传）。
     */
    public static function cdn_path(string $bvid, int $partNum): string
    {
        return "ocr/{$bvid}/p{$partNum}.json";
    }
}