use crate::error::{Error, Result};
use crate::event::Event;
use serde::{Deserialize, Deserializer, Serialize};
//use serde_json::json;
//use serde_json::Result;

// Container for a request filter
#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
#[serde(transparent)]
pub struct ReqCmd {
    cmds: Vec<String>,
}

#[derive(PartialEq, Debug, Clone)]
pub struct Subscription {
    id: String,
    filters: Vec<ReqFilter>,
}

#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
#[serde(deny_unknown_fields)]
pub struct ReqFilter {
    id: Option<String>,
    author: Option<String>,
    kind: Option<u8>,
    #[serde(rename = "e#")]
    event: Option<String>,
    #[serde(rename = "p#")]
    pubkey: Option<String>,
    since: Option<u64>,
    authors: Option<Vec<String>>,
}

impl<'de> Deserialize<'de> for Subscription {
    fn deserialize<D>(deserializer: D) -> Result<Subscription, D::Error>
    where
        D: Deserializer<'de>,
    {
        let mut v: serde_json::Value = Deserialize::deserialize(deserializer)?;
        // this shoud be a 3-or-more element array.
        // verify the first element is a String, REQ
        // get the subscription from the second element.
        // convert each of the remaining objects into filters

        // check for array
        let va = v
            .as_array_mut()
            .ok_or(serde::de::Error::custom("not array"))?;

        // check length
        if va.len() < 3 {
            return Err(serde::de::Error::custom("not enough fields"));
        }
        let mut i = va.into_iter();
        // get command ("REQ") and ensure it is a string
        let req_cmd_str: serde_json::Value = i.next().unwrap().take();
        let req = req_cmd_str.as_str().ok_or(serde::de::Error::custom(
            "first element of request was not a string",
        ))?;
        if req != "REQ" {
            return Err(serde::de::Error::custom("missing REQ command"));
        }

        // ensure sub id is a string
        let sub_id_str: serde_json::Value = i.next().unwrap().take();
        let sub_id = sub_id_str
            .as_str()
            .ok_or(serde::de::Error::custom("missing subscription id"))?;

        let mut filters = vec![];
        for fv in i {
            let f: ReqFilter = serde_json::from_value(fv.take())
                .map_err(|_| serde::de::Error::custom("could not parse filter"))?;
            filters.push(f);
        }
        Ok(Subscription {
            id: sub_id.to_owned(),
            filters,
        })
    }
}

impl Subscription {
    pub fn parse(json: &str) -> Result<Subscription> {
        serde_json::from_str(json).map_err(|e| Error::JsonParseFailed(e))
    }
    pub fn get_id(&self) -> String {
        self.id.clone()
    }
    pub fn get_filter_count(&self) -> usize {
        self.filters.len()
    }
    pub fn interested_in_event(&self, event: &Event) -> bool {
        // loop through every filter, and return true if any match this event.
        for f in self.filters.iter() {
            if f.interested_in_event(event) {
                return true;
            }
        }
    }
}

impl ReqFilter {
    pub fn interested_in_event(&self, event: &Event) -> bool {
        // determine if all populated fields in this filter match the provided event.

        todo!();
        true
    }
}

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

    #[test]
    fn empty_request_parse() -> Result<()> {
        let raw_json = "[\"REQ\",\"some-id\",{}]";
        let s: Subscription = serde_json::from_str(raw_json)?;
        assert_eq!(s.id, "some-id");
        assert_eq!(s.filters.len(), 1);
        assert_eq!(s.filters.get(0).unwrap().author, None);
        Ok(())
    }

    #[test]
    fn multi_empty_request_parse() -> Result<()> {
        let raw_json = r#"["REQ","some-id",{}]"#;
        let s: Subscription = serde_json::from_str(raw_json)?;
        assert_eq!(s.id, "some-id");
        assert_eq!(s.filters.len(), 1);
        assert_eq!(s.filters.get(0).unwrap().author, None);
        Ok(())
    }

    #[test]
    fn incorrect_header() {
        let raw_json = "[\"REQUEST\",\"some-id\",\"{}\"]";
        assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
    }

    #[test]
    fn req_missing_filters() {
        let raw_json = "[\"REQ\",\"some-id\"]";
        assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
    }

    #[test]
    fn invalid_filter() {
        // unrecognized field in filter
        let raw_json = "[\"REQ\",\"some-id\",{\"foo\": 3}]";
        assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
    }

    #[test]
    fn author_filter() -> Result<()> {
        let raw_json = "[\"REQ\",\"some-id\",{\"author\": \"test-author-id\"}]";
        let s: Subscription = serde_json::from_str(raw_json)?;
        assert_eq!(s.id, "some-id");
        assert_eq!(s.filters.len(), 1);
        let first_filter = s.filters.get(0).unwrap();
        assert_eq!(first_filter.author, Some("test-author-id".to_owned()));
        Ok(())
    }
}