use crate::error;
use oxigraph::io::{RdfFormat, RdfParser};
use oxigraph::model::vocab::{rdf, rdfs, xsd};
use oxigraph::model::{
    Dataset, NamedNode, NamedNodeRef, NamedOrBlankNode, NamedOrBlankNodeRef, Term, TermRef, Triple,
    TripleRef,
};
use oxigraph::sparql::{QueryResults, SparqlEvaluator};
use std::collections::{HashMap, HashSet};

const PREFIXES: &[(&str, &str)] = &[
    ("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#"),
    ("rdfs", "http://www.w3.org/2000/01/rdf-schema#"),
    ("owl", "http://www.w3.org/2002/07/owl#"),
    ("xsd", "http://www.w3.org/2001/XMLSchema#"),
    ("ldp", "http://www.w3.org/ns/ldp#"),
    ("dc", "http://purl.org/dc/elements/1.1/"),
    ("posix", "http://www.w3.org/ns/posix/stat#"),
    (
        "ebucore",
        "http://www.ebu.ch/metadata/ontologies/ebucore/ebucore#",
    ),
    ("premis", "http://www.loc.gov/premis/rdf/v1#"),
    ("premis3", "http://www.loc.gov/premis/rdf/v3/"),
    ("dcterms", "http://purl.org/dc/terms/"),
    ("fedora", "http://fedora.info/definitions/v4/repository#"),
    ("rdaa", "http://rdaregistry.info/Elements/a/"),
    ("rdac", "http://rdaregistry.info/Elements/c/"),
    ("rdae", "http://rdaregistry.info/Elements/e/"),
    ("rdai", "http://rdaregistry.info/Elements/i/"),
    ("rdam", "http://rdaregistry.info/Elements/m/"),
    ("rdan", "http://rdaregistry.info/Elements/n/"),
    ("rdap", "http://rdaregistry.info/Elements/p/"),
    ("rdat", "http://rdaregistry.info/Elements/t/"),
    ("rdaw", "http://rdaregistry.info/Elements/w/"),
    ("rdax", "http://rdaregistry.info/Elements/x/"),
    ("schema", "https://schema.org/"),
    ("quill", "http://fedora.quill.lan/rest/"),
    ("gl", "https://graphofliberty.org/2026/04/ont/"),
];

const RDF_ONT: &[u8] = include_bytes!("ontologies/22-rdf-syntax-ns.ttl");
const RDFS_ONT: &[u8] = include_bytes!("ontologies/rdf-schema.ttl");
const LDP_ONT: &[u8] = include_bytes!("ontologies/ldp.ttl");
const FEDORA_ONT: &[u8] = include_bytes!("ontologies/fedora.xml");
const GL_ONT: &[u8] = include_bytes!("ontologies/ontology.ttl");

const GL_READ_ONLY: NamedNodeRef =
    NamedNodeRef::new_unchecked("https://graphofliberty.org/2026/04/ont/ReadOnly");
const GL_TEMPLATE: NamedNodeRef =
    NamedNodeRef::new_unchecked("https://graphofliberty.org/2026/04/ont/template");
const GL_INDEXED_BY_FIELD: NamedNodeRef =
    NamedNodeRef::new_unchecked("https://graphofliberty.org/2026/04/ont/indexedByField");
const GL_CATALOG_ID: NamedNodeRef =
    NamedNodeRef::new_unchecked("https://graphofliberty.org/2026/04/ont/catalogId");
const OWL_SAME_AS: NamedNodeRef =
    NamedNodeRef::new_unchecked("http://www.w3.org/2002/07/owl#sameAs");

pub const RDA_ENTITY: NamedNodeRef =
    NamedNodeRef::new_unchecked("http://rdaregistry.info/Elements/c/C10013");
pub const GL_ENTITY: NamedNodeRef =
    NamedNodeRef::new_unchecked("https://graphofliberty.org/2026/04/ont/Entity");

pub struct OntologyBuilder<'a> {
    ontologies: Vec<(RdfFormat, &'a [u8])>,
}

impl<'a> OntologyBuilder<'a> {
    pub fn with_ontology_bytes(mut self, format: RdfFormat, bytes: &'a [u8]) -> Self {
        self.ontologies.push((format, bytes));
        self
    }

    pub fn with_default_ontologies(self) -> Self {
        self.with_ontology_bytes(RdfFormat::Turtle, RDF_ONT)
            .with_ontology_bytes(RdfFormat::Turtle, RDFS_ONT)
            .with_ontology_bytes(RdfFormat::Turtle, LDP_ONT)
            .with_ontology_bytes(RdfFormat::RdfXml, FEDORA_ONT)
            .with_ontology_bytes(RdfFormat::Turtle, GL_ONT)
    }

    fn materialize_same_as(dataset: &mut Dataset) {
        let additional_quads = dataset
            .quads_for_pattern(None, Some(OWL_SAME_AS), None, None)
            .fold(Dataset::new(), |mut new_dataset, alias| {
                if let NamedOrBlankNodeRef::NamedNode(x) = alias.subject
                    && let TermRef::NamedNode(y) = alias.object
                {
                    for mut quad in dataset.quads_for_pattern(
                        Some(NamedOrBlankNodeRef::NamedNode(x)),
                        None,
                        None,
                        None,
                    ) {
                        quad.subject = NamedOrBlankNodeRef::NamedNode(y);
                        new_dataset.insert(quad);
                    }

                    for mut quad in dataset.quads_for_pattern(
                        Some(NamedOrBlankNodeRef::NamedNode(y)),
                        None,
                        None,
                        None,
                    ) {
                        quad.subject = NamedOrBlankNodeRef::NamedNode(x);
                        new_dataset.insert(quad);
                    }
                }
                new_dataset
            });

        let old_size = dataset.len();
        dataset.extend(&additional_quads);
        let new_size = dataset.len();

        if new_size > old_size {
            Self::materialize_same_as(dataset)
        }
    }

    fn memoize(ontology: &mut Ontology) {
        // Read-only properties
        for quad in ontology.dataset.quads_for_pattern(
            None,
            Some(rdf::TYPE),
            Some(TermRef::NamedNode(GL_READ_ONLY)),
            None,
        ) {
            if let NamedOrBlankNodeRef::NamedNode(subject) = quad.subject {
                ontology.read_only_properties.insert(subject.into_owned());
            }
        }

        // Read-only classes
        for quad in ontology.dataset.quads_for_pattern(
            None,
            Some(rdfs::SUB_CLASS_OF),
            Some(TermRef::NamedNode(GL_READ_ONLY)),
            None,
        ) {
            if let NamedOrBlankNodeRef::NamedNode(subject) = quad.subject {
                ontology.read_only_classes.insert(subject.into_owned());
            }
        }

        // Full-text search index field names
        for quad in ontology
            .dataset
            .quads_for_pattern(None, Some(GL_INDEXED_BY_FIELD), None, None)
        {
            if let NamedOrBlankNodeRef::NamedNode(subject) = quad.subject
                && let TermRef::Literal(literal) = quad.object
            {
                ontology
                    .field_map
                    .insert(subject.into_owned(), literal.value().to_string());
            }
        }

        // Catalog IDs (used to quickly filter full-text search results)
        for quad in ontology
            .dataset
            .quads_for_pattern(None, Some(GL_CATALOG_ID), None, None)
        {
            if let NamedOrBlankNodeRef::NamedNode(subject) = quad.subject
                && let TermRef::Literal(literal) = quad.object
            {
                if literal.datatype() == xsd::POSITIVE_INTEGER {
                    let value: u64 = literal.value().parse().expect("Failed to parse catalog ID from ontology. It ought to be a positive integer.");
                    ontology.catalog_ids.insert(subject.into_owned(), value);
                }
            }
        }
    }

    pub fn build(&mut self) -> error::Result<Ontology> {
        let prefixes = PREFIXES
            .iter()
            .map(|(k, v)| (k.to_string(), v.to_string()))
            .collect::<HashMap<String, String>>();

        let mut dataset = Dataset::new();
        for (format, bytes) in &self.ontologies {
            let quads = RdfParser::from_format(*format)
                .for_slice(bytes)
                .filter_map(Result::ok);
            dataset.extend(quads);
        }
        Self::materialize_same_as(&mut dataset);

        let mut ontology = Ontology {
            dataset,
            prefixes,
            read_only_properties: HashSet::new(),
            read_only_classes: HashSet::new(),
            field_map: HashMap::new(),
            catalog_ids: HashMap::new(),
        };

        Self::memoize(&mut ontology);
        Ok(ontology)
    }
}

pub struct Ontology {
    dataset: Dataset,
    prefixes: HashMap<String, String>,
    read_only_properties: HashSet<NamedNode>,
    read_only_classes: HashSet<NamedNode>,
    field_map: HashMap<NamedNode, String>,
    catalog_ids: HashMap<NamedNode, u64>,
}

fn term_to_string(term: &Term) -> Option<String> {
    match term {
        Term::Literal(literal) => Some(literal.value().to_string()),
        _ => None,
    }
}

impl Ontology {
    pub fn builder<'a>() -> OntologyBuilder<'a> {
        OntologyBuilder {
            ontologies: Vec::new(),
        }
    }

    pub fn label<'a>(&'a self, node: NamedNodeRef<'a>) -> Option<&'a str> {
        let quads = self.dataset.quads_for_pattern(
            Some(NamedOrBlankNodeRef::NamedNode(node)),
            Some(rdfs::LABEL),
            None,
            None,
        );
        for quad in quads {
            if let TermRef::Literal(literal) = quad.object {
                match literal.language() {
                    None | Some("en") => return Some(literal.value()),
                    _ => {}
                }
            }
        }

        None
    }

    pub fn abbreviate(&self, node: NamedNodeRef<'_>) -> String {
        for (prefix_name, prefix_iri) in &self.prefixes {
            if let Some(local_name) = node.as_str().strip_prefix(prefix_iri) {
                return if local_name.is_empty() {
                    format!("{prefix_name}:")
                } else {
                    format!("{prefix_name}:{local_name}")
                };
            }
        }
        node.as_str().to_string()
    }

    pub fn expand(&self, prefixed_iri: &str) -> Option<NamedNode> {
        let (prefix, name) = prefixed_iri.split_once(':')?;
        self.prefixes
            .get(prefix)
            .map(|base| NamedNode::new_unchecked(format!("{base}{name}")))
    }

    pub fn field_name(&self, property: &NamedNode) -> Option<&String> {
        self.field_map.get(property)
    }

    pub fn catalog_id(&self, class: &NamedNode) -> Option<u64> {
        self.catalog_ids.get(class).copied()
    }

    pub fn for_each_annotated_iri<F>(&self, f: F)
    where
        F: Fn(&str, Option<&str>, Option<&str>),
    {
        let query = SparqlEvaluator::new()
            .parse_query(
                r"PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT ?subject ?label ?comment WHERE {
    OPTIONAL {
        ?subject rdfs:label ?label .
        FILTER (LANG(?label) = 'en' || LANG(?label) = '')
    }
    OPTIONAL {
        ?subject rdfs:comment ?comment .
        FILTER (LANG(?comment) = 'en' || LANG(?comment) = '')
    }
}",
            )
            .expect("Unable to parse annotation query");

        if let QueryResults::Solutions(solutions) =
            query.on_queryable_dataset(&self.dataset).execute().unwrap()
        {
            for solution in solutions.filter_map(Result::ok) {
                let label = solution.get("label").and_then(term_to_string);
                let comment = solution.get("comment").and_then(term_to_string);
                if let Some(Term::NamedNode(subject)) = solution.get("subject") {
                    f(subject.as_str(), label.as_deref(), comment.as_deref());
                }
            }
        }
    }

    pub fn datatypes(&self) -> impl Iterator<Item = NamedNodeRef<'_>> {
        self.dataset
            .quads_for_pattern(
                None,
                Some(rdf::TYPE),
                Some(TermRef::NamedNode(rdfs::DATATYPE)),
                None,
            )
            .filter_map(|quad| match quad.subject {
                NamedOrBlankNodeRef::NamedNode(subject) => Some(subject),
                _ => None,
            })
    }

    pub fn is_read_only<'a>(&self, triple: impl Into<TripleRef<'a>>) -> bool {
        let triple = triple.into();
        let read_only_property = self
            .read_only_properties
            .contains(&triple.predicate.into_owned());
        let read_only_class = match (triple.predicate, triple.object) {
            (rdf::TYPE, TermRef::NamedNode(node)) => {
                self.read_only_classes.contains(&node.into_owned())
            }
            _ => false,
        };
        read_only_property || read_only_class
    }

    pub fn exclude_read_only_predicate(&self) -> impl Fn(TripleRef<'_>) -> bool + 'static {
        let classes = self.read_only_classes.clone();
        let properties = self.read_only_properties.clone();
        move |triple| {
            let read_only_property = properties.contains(&triple.predicate.into_owned());
            let read_only_class = match (triple.predicate, triple.object) {
                (rdf::TYPE, TermRef::NamedNode(node)) => classes.contains(&node.into_owned()),
                _ => false,
            };
            !(read_only_property || read_only_class)
        }
    }

    pub fn subclass_of(&self, class: NamedNodeRef<'_>) -> impl Iterator<Item = NamedNode> {
        let query = SparqlEvaluator::new()
            .parse_query(
                format!(
                    "PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?class {{
    ?class (rdfs:subClassOf|^rdfs:subClassOf)* {class} .
}}"
                )
                .as_str(),
            )
            .expect("Unable to parse subclass_of query");

        if let QueryResults::Solutions(solutions) =
            query.on_queryable_dataset(&self.dataset).execute().unwrap()
        {
            solutions.filter_map(Result::ok).filter_map(|solution| {
                if let Some(Term::NamedNode(class)) = solution.get("class") {
                    Some(class.clone())
                } else {
                    None
                }
            })
        } else {
            unreachable!()
        }
    }

    pub fn template_triples<'a>(
        &'a self,
        class: NamedNodeRef<'a>,
        subject: NamedNodeRef<'_>,
    ) -> Option<impl Iterator<Item = Triple>> {
        if let Some(quad) = self
            .dataset
            .quads_for_pattern(
                Some(NamedOrBlankNodeRef::NamedNode(class)),
                Some(GL_TEMPLATE),
                None,
                None,
            )
            .next()
        {
            if let TermRef::BlankNode(blank_node) = quad.object {
                let iter = self
                    .dataset
                    .quads_for_subject(blank_node)
                    .map(|quad| quad.into_owned())
                    .map(Triple::from)
                    .map(move |mut triple| {
                        triple.subject = NamedOrBlankNode::NamedNode(subject.into_owned());
                        triple
                    });
                Some(iter)
            } else {
                None
            }
        } else {
            None
        }
    }
}