use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
use crate::{config::DynNode, error::ServiceError};
use futures::Future;
use http::Uri;
use regex::{Regex, RegexSet};
use serde_yml::Value;
use std::{collections::BTreeMap, pin::Pin, sync::Arc};

pub struct PathsKind;

struct Paths {
    matcher: RegexSet,
    extractors: Vec<Regex>,
    handlers: Vec<DynNode>,
}

impl NodeKind for PathsKind {
    fn name(&self) -> &'static str {
        "paths"
    }
    fn instanciate(&self, config: Value) -> anyhow::Result<Arc<dyn Node>> {
        let routes = serde_yml::from_value::<BTreeMap<String, DynNode>>(config)?
            .into_iter()
            .collect::<Vec<(String, DynNode)>>();

        let mut handlers = Vec::new();
        let mut patterns = Vec::new();
        let mut extractors = Vec::new();
        for (k, v) in routes {
            let pattern = format!("^{k}$");
            handlers.push(v);
            extractors.push(Regex::new(&pattern)?);
            patterns.push(pattern);
        }
        let matcher = RegexSet::new(&patterns)?;

        Ok(Arc::new(Paths {
            handlers,
            matcher,
            extractors,
        }))
    }
}
impl Node for Paths {
    fn handle<'a>(
        &'a self,
        context: &'a mut NodeContext,
        mut request: NodeRequest,
    ) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
        Box::pin(async move {
            let path = request.uri().path();

            let index = self
                .matcher
                .matches(path)
                .iter()
                .next()
                .ok_or(ServiceError::UnknownPath)?;

            let caps = self.extractors[index]
                .captures(path)
                .ok_or(ServiceError::Other)?;

            if let Some(rest) = caps.get(1) {
                let mut parts = http::uri::Parts::default();
                parts.scheme = request.uri().scheme().cloned();
                parts.authority = request.uri().authority().cloned();
                parts.path_and_query =
                    Some(rest.as_str().parse().map_err(|_| ServiceError::Other)?);
                *request.uri_mut() = Uri::from_parts(parts).map_err(|_| ServiceError::InvalidUri)?
            }

            self.handlers[index].handle(context, request).await
        })
    }
}