use crate::DbPool;
use crate::providers::Provider;
use crate::util::cache::VideoCache;
use crate::util::discord::send_discord_error_report;
use crate::util::parse_abbreviated_number;
use crate::util::time::parse_time_to_seconds;
use crate::videos::{ServerOptions, VideoItem};
use async_trait::async_trait;
use error_chain::error_chain;
use htmlentity::entity::{ICodedDataTrait, decode};
use std::time::{SystemTime, UNIX_EPOCH};
use std::vec;

error_chain! {
    foreign_links {
        Io(std::io::Error);
        HttpRequest(wreq::Error);
    }
    errors {
        ParsingError(t: String) {
            description("html parsing error")
            display("HTML parsing error: '{}'", t)
        }
    }
}

#[derive(Debug, Clone)]
pub struct Rule34videoProvider {
    url: String,
}

impl Rule34videoProvider {
    pub fn new() -> Self {
        Rule34videoProvider {
            url: "https://rule34video.com".to_string(),
        }
    }

    /// Helper to safely extract a string between two delimiters
    fn extract_between<'a>(content: &'a str, start_pat: &str, end_pat: &str) -> Option<&'a str> {
        let start_idx = content.find(start_pat)? + start_pat.len();
        let sub = &content[start_idx..];
        let end_idx = sub.find(end_pat)?;
        Some(&sub[..end_idx])
    }

    async fn get(
        &self,
        cache: VideoCache,
        page: u8,
        sort: &str,
        options: ServerOptions,
    ) -> Result<Vec<VideoItem>> {
        let timestamp_millis = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .map(|d| d.as_millis())
            .unwrap_or(0);

        let expected_sorts = vec![
            "post_date",
            "video_viewed",
            "rating",
            "duration",
            "pseudo_random",
        ];
        let sort_val = if expected_sorts.contains(&sort) {
            sort
        } else {
            "post_date"
        };

        let index = format!("rule34video:{}:{}", page, sort_val);

        if sort_val != "pseudo_random" {
            if let Some((time, items)) = cache.get(&index) {
                if time.elapsed().unwrap_or_default().as_secs() < 300 {
                    return Ok(items.clone());
                }
            }
        }

        let mut requester = options.requester.clone().ok_or("Requester missing")?;
        let url = format!(
            "{}/?mode=async&function=get_block&block_id=custom_list_videos_most_recent_videos&tag_ids=&sort_by={}&from={}&_={}",
            self.url, sort_val, page, timestamp_millis
        );

        let text = requester.get(&url, None).await.unwrap_or_else(|e| {
            eprintln!("Error fetching rule34video URL {}: {}", url, e);
            let _ = send_discord_error_report(e.to_string(), None, Some(&url), None, file!(), line!(), module_path!());
            "".to_string()
        });
        let video_items = self.get_video_items_from_html(text);

        if !video_items.is_empty() {
            cache.insert(index, video_items.clone());
            Ok(video_items)
        } else {
            // Return empty or old items if available
            Ok(cache
                .get(&index)
                .map(|(_, items)| items)
                .unwrap_or_default())
        }
    }

    async fn query(
        &self,
        cache: VideoCache,
        page: u8,
        query: &str,
        sort: &str,
        options: ServerOptions,
    ) -> Result<Vec<VideoItem>> {
        let timestamp_millis = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .map(|d| d.as_millis())
            .unwrap_or(0);

        let expected_sorts = vec![
            "post_date",
            "video_viewed",
            "rating",
            "duration",
            "pseudo_random",
        ];
        let sort_val = if expected_sorts.contains(&sort) {
            sort
        } else {
            "post_date"
        };

        let index = format!("rule34video:{}:{}:{}", page, sort_val, query);

        if let Some((time, items)) = cache.get(&index) {
            if time.elapsed().unwrap_or_default().as_secs() < 300 {
                return Ok(items.clone());
            }
        }

        let mut requester = options.requester.clone().ok_or("Requester missing")?;
        let url = format!(
            "{}/search/{}/?mode=async&function=get_block&block_id=custom_list_videos_videos_list_search&tag_ids=&sort_by={}&from_videos={}&from_albums={}&_={}",
            self.url,
            query.replace(" ", "-"),
            sort_val,
            page,
            page,
            timestamp_millis
        );

        let text = requester.get(&url, None).await.unwrap_or_else(|e| {
            eprintln!("Error fetching rule34video URL {}: {}", url, e);
            let _ = send_discord_error_report(e.to_string(), None, Some(&url), None, file!(), line!(), module_path!());
            "".to_string()
        });
        let video_items = self.get_video_items_from_html(text);

        if !video_items.is_empty() {
            cache.insert(index, video_items.clone());
            Ok(video_items)
        } else {
            Ok(cache
                .get(&index)
                .map(|(_, items)| items)
                .unwrap_or_default())
        }
    }

    fn get_video_items_from_html(&self, html: String) -> Vec<VideoItem> {
        if html.is_empty() {
            return vec![];
        }

        // Safely isolate the video listing section
        let video_listing = match Self::extract_between(
            &html,
            "id=\"custom_list_videos",
            "<div class=\"pagination\"",
        ) {
            Some(content) => content,
            None => return vec![],
        };

        let mut items = Vec::new();
        // Skip the first split result as it's the preamble
        let raw_videos = video_listing
            .split("<div class=\"item thumb video_")
            .skip(1);

        for video_segment in raw_videos {
            if video_segment.contains("title=\"Advertisement\"") {
                continue;
            }

            // Title extraction
            let title_raw =
                Self::extract_between(video_segment, "<div class=\"thumb_title\">", "<")
                    .unwrap_or("Unknown");
            let title = decode(title_raw.as_bytes())
                .to_string()
                .unwrap_or_else(|_| title_raw.to_string());

            // ID extraction
            let id = Self::extract_between(video_segment, "https://rule34video.com/video/", "/")
                .unwrap_or("0")
                .to_string();

            // Duration extraction
            let raw_duration =
                Self::extract_between(video_segment, "<div class=\"time\">", "<").unwrap_or("0:00");
            let duration = parse_time_to_seconds(raw_duration).unwrap_or(0) as u32;

            // Views extraction
            let views_segment = Self::extract_between(video_segment, "<div class=\"views\">", "<");
            let views_count_str = views_segment
                .and_then(|s| s.split("</svg>").nth(1))
                .unwrap_or("0");
            let views = parse_abbreviated_number(views_count_str.trim()).unwrap_or(0);

            // Thumbnail extraction
            let thumb = Self::extract_between(video_segment, "data-original=\"", "\"")
                .unwrap_or("")
                .to_string();

            // URL extraction
            let url =
                Self::extract_between(video_segment, "<a class=\"th js-open-popup\" href=\"", "\"")
                    .unwrap_or("")
                    .to_string();

            items.push(
                VideoItem::new(id, title, url, "Rule34video".to_string(), thumb, duration)
                    .views(views),
            );
        }
        items
    }
}

#[async_trait]
impl Provider for Rule34videoProvider {
    async fn get_videos(
        &self,
        cache: VideoCache,
        _pool: DbPool,
        sort: String,
        query: Option<String>,
        page: String,
        _per_page: String,
        options: ServerOptions,
    ) -> Vec<VideoItem> {
        let page_num = page.parse::<u8>().unwrap_or(1);

        let result = match query {
            Some(q) => self.query(cache, page_num, &q, &sort, options).await,
            None => self.get(cache, page_num, &sort, options).await,
        };

        match result {
            Ok(v) => v,
            Err(e) => {
                eprintln!("Error fetching videos: {}", e);
                vec![]
            }
        }
    }
}