use ntex::web;
use regex::Regex;
use wreq::Version;

use crate::util::requester::Requester;

#[derive(Debug, Clone)]
pub struct SpankbangProxy {}

impl SpankbangProxy {
    pub fn new() -> Self {
        SpankbangProxy {}
    }

    fn request_headers() -> Vec<(String, String)> {
        vec![("Referer".to_string(), "https://spankbang.com/".to_string())]
    }

    fn extract_stream_data(text: &str) -> Option<&str> {
        let marker = "var stream_data = ";
        let start = text.find(marker)? + marker.len();
        let rest = &text[start..];
        let end = rest.find("};")?;
        Some(&rest[..=end])
    }

    fn extract_first_stream_url(stream_data: &str, key: &str) -> Option<String> {
        let pattern = format!(r"'{}'\s*:\s*\[\s*'([^']+)'", regex::escape(key));
        let regex = Regex::new(&pattern).ok()?;
        regex
            .captures(stream_data)
            .and_then(|captures| captures.get(1))
            .map(|value| value.as_str().to_string())
    }

    fn select_best_stream_url(stream_data: &str) -> Option<String> {
        for key in [
            "m3u8", "4k", "1080p", "720p", "480p", "320p", "240p", "main",
        ] {
            if let Some(url) = Self::extract_first_stream_url(stream_data, key) {
                return Some(url);
            }
        }

        None
    }

    pub async fn get_video_url(
        &self,
        url: String,
        requester: web::types::State<Requester>,
    ) -> String {
        let mut requester = requester.get_ref().clone();
        let url = format!("https://spankbang.com/{}", url.trim_start_matches('/'));
        let text = requester
            .get_with_headers(&url, Self::request_headers(), Some(Version::HTTP_2))
            .await
            .unwrap_or_default();
        if text.is_empty() {
            return String::new();
        }

        let Some(stream_data) = Self::extract_stream_data(&text) else {
            return String::new();
        };

        Self::select_best_stream_url(stream_data).unwrap_or_default()
    }
}

#[cfg(test)]
mod tests {
    use super::SpankbangProxy;

    #[test]
    fn prefers_m3u8_when_present() {
        assert_eq!(
            SpankbangProxy::request_headers(),
            vec![("Referer".to_string(), "https://spankbang.com/".to_string())]
        );

        let data = r#"
            var stream_data = {'240p': ['https://cdn.example/240.mp4'], '720p': ['https://cdn.example/720.mp4'], 'm3u8': ['https://cdn.example/master.m3u8'], 'main': ['https://cdn.example/720.mp4']};
        "#;

        let stream_data = SpankbangProxy::extract_stream_data(data).unwrap();
        assert_eq!(
            SpankbangProxy::select_best_stream_url(stream_data).as_deref(),
            Some("https://cdn.example/master.m3u8")
        );
    }

    #[test]
    fn falls_back_to_highest_quality_mp4() {
        let data = r#"
            var stream_data = {'240p': ['https://cdn.example/240.mp4'], '480p': ['https://cdn.example/480.mp4'], '720p': ['https://cdn.example/720.mp4'], '1080p': [], '4k': [], 'm3u8': [], 'main': ['https://cdn.example/480.mp4']};
        "#;

        let stream_data = SpankbangProxy::extract_stream_data(data).unwrap();
        assert_eq!(
            SpankbangProxy::select_best_stream_url(stream_data).as_deref(),
            Some("https://cdn.example/720.mp4")
        );
    }
}