use crate::files::load_to_graph;
use crate::vocab::*;
use anyhow::{anyhow, Result};
use oxigraph::model::vocab::*;
use oxigraph::model::*;
use std::fmt;

pub struct Test {
    pub id: NamedNode,
    pub kind: NamedNode,
    pub name: Option<String>,
    pub comment: Option<String>,
    pub action: Option<String>,
    pub query: Option<String>,
    pub update: Option<String>,
    pub data: Option<String>,
    pub graph_data: Vec<(NamedNode, String)>,
    pub service_data: Vec<(String, String)>,
    pub result: Option<String>,
    pub result_graph_data: Vec<(NamedNode, String)>,
}

impl fmt::Display for Test {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.kind)?;
        for name in &self.name {
            write!(f, " named \"{}\"", name)?;
        }
        for comment in &self.comment {
            write!(f, " with comment \"{}\"", comment)?;
        }
        if let Some(action) = &self.action {
            write!(f, " on file \"{}\"", action)?;
        }
        if let Some(query) = &self.query {
            write!(f, " on query {}", &query)?;
        }
        for data in &self.data {
            write!(f, " with data {}", data)?;
        }
        for (_, data) in &self.graph_data {
            write!(f, " and graph data {}", data)?;
        }
        for result in &self.result {
            write!(f, " and expected result {}", result)?;
        }
        Ok(())
    }
}

pub struct TestManifest {
    graph: Graph,
    tests_to_do: Vec<Term>,
    manifests_to_do: Vec<String>,
}

impl TestManifest {
    pub fn new<S: ToString>(manifest_urls: impl IntoIterator<Item = S>) -> Self {
        Self {
            graph: Graph::new(),
            tests_to_do: Vec::new(),
            manifests_to_do: manifest_urls
                .into_iter()
                .map(|url| url.to_string())
                .collect(),
        }
    }
}

impl Iterator for TestManifest {
    type Item = Result<Test>;

    fn next(&mut self) -> Option<Result<Test>> {
        match self.tests_to_do.pop() {
            Some(Term::NamedNode(test_node)) => {
                let kind = match self
                    .graph
                    .object_for_subject_predicate(&test_node, rdf::TYPE)
                {
                    Some(TermRef::NamedNode(c)) => c.into_owned(),
                    _ => return self.next(), //We ignore the test
                };
                let name = match self
                    .graph
                    .object_for_subject_predicate(&test_node, mf::NAME)
                {
                    Some(TermRef::Literal(c)) => Some(c.value().to_string()),
                    _ => None,
                };
                let comment = match self
                    .graph
                    .object_for_subject_predicate(&test_node, rdfs::COMMENT)
                {
                    Some(TermRef::Literal(c)) => Some(c.value().to_string()),
                    _ => None,
                };
                let (action, query, update, data, graph_data, service_data) = match self
                    .graph
                    .object_for_subject_predicate(&test_node, mf::ACTION)
                {
                    Some(TermRef::NamedNode(n)) => (
                        Some(n.as_str().to_owned()),
                        None,
                        None,
                        None,
                        vec![],
                        vec![],
                    ),
                    Some(TermRef::BlankNode(n)) => {
                        let query = match self.graph.object_for_subject_predicate(n, qt::QUERY) {
                            Some(TermRef::NamedNode(q)) => Some(q.as_str().to_owned()),
                            _ => None,
                        };
                        let update = match self.graph.object_for_subject_predicate(n, ut::REQUEST) {
                            Some(TermRef::NamedNode(q)) => Some(q.as_str().to_owned()),
                            _ => None,
                        };
                        let data = match self
                            .graph
                            .object_for_subject_predicate(n, qt::DATA)
                            .or_else(|| self.graph.object_for_subject_predicate(n, ut::DATA))
                        {
                            Some(TermRef::NamedNode(q)) => Some(q.as_str().to_owned()),
                            _ => None,
                        };
                        let graph_data = self
                            .graph
                            .objects_for_subject_predicate(n, qt::GRAPH_DATA)
                            .chain(self.graph.objects_for_subject_predicate(n, ut::GRAPH_DATA))
                            .filter_map(|g| match g {
                                TermRef::NamedNode(q) => {
                                    Some((q.into_owned(), q.as_str().to_owned()))
                                }
                                TermRef::BlankNode(node) => {
                                    if let Some(TermRef::NamedNode(graph)) =
                                        self.graph.object_for_subject_predicate(node, ut::GRAPH)
                                    {
                                        if let Some(TermRef::Literal(name)) = self
                                            .graph
                                            .object_for_subject_predicate(node, rdfs::LABEL)
                                        {
                                            Some((
                                                NamedNode::new(name.value()).unwrap(),
                                                graph.as_str().to_owned(),
                                            ))
                                        } else {
                                            Some((graph.into_owned(), graph.as_str().to_owned()))
                                        }
                                    } else {
                                        None
                                    }
                                }
                                _ => None,
                            })
                            .collect();
                        let service_data = self
                            .graph
                            .objects_for_subject_predicate(n, qt::SERVICE_DATA)
                            .filter_map(|g| match g {
                                TermRef::NamedNode(g) => Some(g.into()),
                                TermRef::BlankNode(g) => Some(g.into()),
                                _ => None,
                            })
                            .filter_map(|g: SubjectRef<'_>| {
                                if let (
                                    Some(TermRef::NamedNode(endpoint)),
                                    Some(TermRef::NamedNode(data)),
                                ) = (
                                    self.graph.object_for_subject_predicate(g, qt::ENDPOINT),
                                    self.graph.object_for_subject_predicate(g, qt::DATA),
                                ) {
                                    Some((endpoint.as_str().to_owned(), data.as_str().to_owned()))
                                } else {
                                    None
                                }
                            })
                            .collect();
                        (None, query, update, data, graph_data, service_data)
                    }
                    Some(_) => return Some(Err(anyhow!("invalid action"))),
                    None => {
                        return Some(Err(anyhow!("action not found for test {}", test_node)));
                    }
                };
                let (result, result_graph_data) = match self
                    .graph
                    .object_for_subject_predicate(&test_node, mf::RESULT)
                {
                    Some(TermRef::NamedNode(n)) => (Some(n.as_str().to_owned()), Vec::new()),
                    Some(TermRef::BlankNode(n)) => (
                        if let Some(TermRef::NamedNode(result)) =
                            self.graph.object_for_subject_predicate(n, ut::DATA)
                        {
                            Some(result.as_str().to_owned())
                        } else {
                            None
                        },
                        self.graph
                            .objects_for_subject_predicate(n, ut::GRAPH_DATA)
                            .filter_map(|g| match g {
                                TermRef::NamedNode(q) => {
                                    Some((q.into_owned(), q.as_str().to_owned()))
                                }
                                TermRef::BlankNode(node) => {
                                    if let Some(TermRef::NamedNode(graph)) =
                                        self.graph.object_for_subject_predicate(node, ut::GRAPH)
                                    {
                                        if let Some(TermRef::Literal(name)) = self
                                            .graph
                                            .object_for_subject_predicate(node, rdfs::LABEL)
                                        {
                                            Some((
                                                NamedNode::new(name.value()).unwrap(),
                                                graph.as_str().to_owned(),
                                            ))
                                        } else {
                                            Some((graph.into_owned(), graph.as_str().to_owned()))
                                        }
                                    } else {
                                        None
                                    }
                                }
                                _ => None,
                            })
                            .collect(),
                    ),
                    Some(_) => return Some(Err(anyhow!("invalid result"))),
                    None => (None, Vec::new()),
                };
                Some(Ok(Test {
                    id: test_node,
                    kind,
                    name,
                    comment,
                    action,
                    query,
                    update,
                    data,
                    graph_data,
                    service_data,
                    result,
                    result_graph_data,
                }))
            }
            Some(_) => self.next(),
            None => {
                match self.manifests_to_do.pop() {
                    Some(url) => {
                        self.graph.clear();
                        if let Err(error) = load_to_graph(&url, &mut self.graph) {
                            return Some(Err(error));
                        }

                        for manifest in self
                            .graph
                            .subjects_for_predicate_object(rdf::TYPE, mf::MANIFEST)
                        {
                            match self
                                .graph
                                .object_for_subject_predicate(manifest, mf::INCLUDE)
                            {
                                Some(TermRef::BlankNode(list)) => {
                                    self.manifests_to_do.extend(
                                        RdfListIterator::iter(&self.graph, list.into()).filter_map(
                                            |m| match m {
                                                Term::NamedNode(nm) => Some(nm.into_string()),
                                                _ => None,
                                            },
                                        ),
                                    );
                                }
                                Some(_) => return Some(Err(anyhow!("invalid tests list"))),
                                None => (),
                            }

                            // New tests
                            match self
                                .graph
                                .object_for_subject_predicate(manifest, mf::ENTRIES)
                            {
                                Some(TermRef::BlankNode(list)) => {
                                    self.tests_to_do
                                        .extend(RdfListIterator::iter(&self.graph, list.into()));
                                }
                                Some(term) => {
                                    return Some(Err(anyhow!(
                                        "Invalid tests list. Got term {}",
                                        term
                                    )));
                                }
                                None => (),
                            }
                        }
                    }
                    None => return None,
                }
                self.next()
            }
        }
    }
}

struct RdfListIterator<'a> {
    graph: &'a Graph,
    current_node: Option<SubjectRef<'a>>,
}

impl<'a> RdfListIterator<'a> {
    fn iter(graph: &'a Graph, root: SubjectRef<'a>) -> RdfListIterator<'a> {
        RdfListIterator {
            graph,
            current_node: Some(root),
        }
    }
}

impl<'a> Iterator for RdfListIterator<'a> {
    type Item = Term;

    fn next(&mut self) -> Option<Term> {
        match self.current_node {
            Some(current) => {
                let result = self
                    .graph
                    .object_for_subject_predicate(current, rdf::FIRST)
                    .map(|v| v.into_owned());
                self.current_node =
                    match self.graph.object_for_subject_predicate(current, rdf::REST) {
                        Some(TermRef::NamedNode(n)) if n == rdf::NIL => None,
                        Some(TermRef::NamedNode(n)) => Some(n.into()),
                        Some(TermRef::BlankNode(n)) => Some(n.into()),
                        _ => None,
                    };
                result
            }
            None => None,
        }
    }
}