#![doc = include_str!("../README.md")]
#![warn(
    elided_lifetimes_in_paths,
    explicit_outlives_requirements,
    missing_debug_implementations,
    missing_docs,
    noop_method_call,
    single_use_lifetimes,
    trivial_casts,
    trivial_numeric_casts,
    unreachable_pub,
    unsafe_code,
    unused_crate_dependencies,
    unused_qualifications
)]
#![warn(clippy::pedantic, clippy::cargo)]

#[cfg(feature = "parse-knuffel")]
use knuffel::{Decode, DecodeScalar};

mod schema_schema;
pub use schema_schema::SCHEMA_SCHEMA;

pub(crate) trait BuildFromRef {
    fn ref_to(query: impl Into<String>) -> Self;
}

fn get_id_from_ref(r#ref: &str) -> Option<&str> {
    r#ref
        .strip_prefix(r#"[id=""#)
        .and_then(|r#ref| r#ref.strip_suffix(r#""]"#))
}

/// the schema itself
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Schema {
    /// the document this schema defines
    ///
    /// this is redundant but it matches the schema document structure
    #[cfg_attr(feature = "parse-knuffel", knuffel(child))]
    pub document: Document,
}

impl Schema {
    /// find the node matching the given ref
    ///
    /// # Panics
    ///
    /// Panics if ref is not of the form `[id="foo"]`.
    #[must_use]
    pub fn resolve_node_ref(&self, r#ref: &str) -> Option<&Node> {
        let id = get_id_from_ref(r#ref).expect("invalid ref");
        self.document
            .nodes
            .iter()
            .find_map(|node| node.find_node_by_id(id))
    }

    /// find the prop matching the given ref
    ///
    /// # Panics
    ///
    /// Panics if ref is not of the form `[id="foo"]`.
    #[must_use]
    pub fn resolve_prop_ref(&self, r#ref: &str) -> Option<&Prop> {
        let id = get_id_from_ref(r#ref).expect("invalid ref");
        self.document
            .nodes
            .iter()
            .find_map(|node| node.find_prop_by_id(id))
    }

    /// find the value matching the given ref
    ///
    /// # Panics
    ///
    /// Panics if ref is not of the form `[id="foo"]`.
    #[must_use]
    pub fn resolve_value_ref(&self, r#ref: &str) -> Option<&Value> {
        let id = get_id_from_ref(r#ref).expect("invalid ref");
        self.document
            .nodes
            .iter()
            .find_map(|node| node.find_value_by_id(id))
    }

    /// find the children matching the given ref
    ///
    /// # Panics
    ///
    /// Panics if ref is not of the form `[id="foo"]`.
    #[must_use]
    pub fn resolve_children_ref(&self, r#ref: &str) -> Option<&Children> {
        let id = get_id_from_ref(r#ref).expect("invalid ref");
        self.document
            .nodes
            .iter()
            .find_map(|node| node.find_children_by_id(id))
    }
}

#[cfg(feature = "parse-knuffel")]
impl Schema {
    /// parse a KDL schema definition
    ///
    /// # Errors
    ///
    /// returns an error if knuffel can't parse the document as a Schema
    pub fn parse(schema_kdl: &str) -> Result<Self, knuffel::Error> {
        knuffel::parse("<Schema::parse argument>", schema_kdl)
    }
}

/// the schema document
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Document {
    /// schema metadata
    #[cfg_attr(feature = "parse-knuffel", knuffel(child))]
    pub info: Info,
    /// top-level node definitions
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "node")))]
    pub nodes: Vec<Node>,
}

/// schema metadata
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Info {
    /// schema titles
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "title")))]
    pub title: Vec<TextValue>,
    /// schema descriptions
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "description")))]
    pub description: Vec<TextValue>,
    /// schema authors
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "author")))]
    pub authors: Vec<Person>,
    /// schema contributors
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "contributor")))]
    pub contributors: Vec<Person>,
    /// schema links
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "link")))]
    pub links: Vec<Link>,
    /// schema licenses
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "license")))]
    pub licenses: Vec<License>,
    /// schema publication date
    #[cfg_attr(feature = "parse-knuffel", knuffel(child))]
    pub published: Option<Date>,
    /// schema modification date
    #[cfg_attr(feature = "parse-knuffel", knuffel(child))]
    pub modified: Option<Date>,
}

/// a text value with an optional language tag
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct TextValue {
    /// text itself
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub text: String,
    /// BCP 47 language tag
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub lang: Option<String>,
}

/// information about a schema author/contributor
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Person {
    /// name
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub name: String,
    /// [ORCID](https://orcid.org)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub orcid: Option<String>,
    /// relevant links
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "link")))]
    pub links: Vec<Link>,
}

/// link related to specification metadata, with optional relationship and language tag
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Link {
    /// URI/IRI of link target
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub iri: String,
    /// relationship of link to schema (`self`, `documentation`)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub rel: Option<String>,
    /// BCP 47 language tag
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub lang: Option<String>,
}

/// schema license information
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct License {
    /// license name
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub name: String,
    /// license [SPDX identifier](https://spdx.org/licenses/)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub spdx: Option<String>,
    /// links for license information
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "link")))]
    pub link: Vec<Link>,
}

/// date with optional time
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Date {
    /// date
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub date: String,
    /// time
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub time: Option<String>,
}

/// schema for a node
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Node {
    /// name of the node (applies to all nodes at this level if `None`)
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub name: Option<String>,
    /// id of the node (can be used for refs)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub id: Option<String>,
    /// human-readable description of the node's purpose
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub description: Option<String>,
    /// KDL query from which to load node information instead of specifying it inline (allows for recursion)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub r#ref: Option<String>,
    /// minimum number of occurrences of this node
    #[cfg_attr(feature = "parse-knuffel", knuffel(child, unwrap(argument)))]
    pub min: Option<usize>,
    /// maximum number of occurrences of this node
    #[cfg_attr(feature = "parse-knuffel", knuffel(child, unwrap(argument)))]
    pub max: Option<usize>,
    /// properties allowed on this node
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "prop")))]
    pub props: Vec<Prop>,
    /// values allowed on this node
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "value")))]
    pub values: Vec<Value>,
    /// children allowed on this node
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "children")))]
    pub children: Vec<Children>,
}

impl Node {
    fn find_node_by_id(&self, id: &str) -> Option<&Node> {
        if self.id.as_deref() == Some(id) {
            Some(self)
        } else {
            self.children
                .iter()
                .find_map(|children| children.find_node_by_id(id))
        }
    }

    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
        self.props
            .iter()
            .find_map(|prop| prop.find_prop_by_id(id))
            .or_else(|| {
                self.children
                    .iter()
                    .find_map(|children| children.find_prop_by_id(id))
            })
    }

    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
        self.values
            .iter()
            .find_map(|value| value.find_value_by_id(id))
            .or_else(|| {
                self.children
                    .iter()
                    .find_map(|children| children.find_value_by_id(id))
            })
    }

    fn find_children_by_id(&self, id: &str) -> Option<&Children> {
        self.children
            .iter()
            .find_map(|children| children.find_children_by_id(id))
    }
}

impl BuildFromRef for Node {
    fn ref_to(query: impl Into<String>) -> Self {
        Self {
            r#ref: Some(query.into()),
            ..Self::default()
        }
    }
}

/// schema for a property
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Prop {
    /// property key (applies to all properties in this node if `None`)
    #[cfg_attr(feature = "parse-knuffel", knuffel(argument))]
    pub key: Option<String>,
    /// id of the property (can be used for refs)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub id: Option<String>,
    /// human-readable description of the property
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub description: Option<String>,
    /// KDL query from which to load property information instead of specifying it inline (allows for recursion)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub r#ref: Option<String>,
    /// whether or not this property is required
    #[cfg_attr(feature = "parse-knuffel", knuffel(child))]
    pub required: bool,
    /// validations to apply to the property value
    #[cfg_attr(feature = "parse-knuffel", knuffel(children))]
    pub validations: Vec<Validation>,
}

impl Prop {
    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
        if self.id.as_deref() == Some(id) {
            Some(self)
        } else {
            None
        }
    }
}

impl BuildFromRef for Prop {
    fn ref_to(query: impl Into<String>) -> Self {
        Self {
            r#ref: Some(query.into()),
            ..Self::default()
        }
    }
}

/// schema for a value
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Value {
    /// id of the value (can be used for refs)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub id: Option<String>,
    /// human readable description of the value
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub description: Option<String>,
    /// KDL query from which to load value information instead of specifying it inline (allows for recursion)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub r#ref: Option<String>,
    /// minimum number of occurrences of this value
    #[cfg_attr(feature = "parse-knuffel", knuffel(child, unwrap(argument)))]
    pub min: Option<usize>,
    /// maximum number of occurrences of this value
    #[cfg_attr(feature = "parse-knuffel", knuffel(child, unwrap(argument)))]
    pub max: Option<usize>,
    /// validations to apply to this value
    #[cfg_attr(feature = "parse-knuffel", knuffel(children))]
    pub validations: Vec<Validation>,
}

impl Value {
    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
        if self.id.as_deref() == Some(id) {
            Some(self)
        } else {
            None
        }
    }
}

impl BuildFromRef for Value {
    fn ref_to(query: impl Into<String>) -> Self {
        Self {
            r#ref: Some(query.into()),
            ..Self::default()
        }
    }
}

/// schema for a node's children
#[derive(Debug, PartialEq, Eq, Default)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub struct Children {
    /// id for these children (can be used for refs)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub id: Option<String>,
    /// human readable description of these children
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub description: Option<String>,
    /// KDL query from which to load children information instead of specifying it inline (allows for recursion)
    #[cfg_attr(feature = "parse-knuffel", knuffel(property))]
    pub r#ref: Option<String>,
    /// nodes which can appear as children
    #[cfg_attr(feature = "parse-knuffel", knuffel(children(name = "node")))]
    pub nodes: Vec<Node>,
}

impl Children {
    fn find_node_by_id(&self, id: &str) -> Option<&Node> {
        self.nodes.iter().find_map(|node| node.find_node_by_id(id))
    }

    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
        self.nodes.iter().find_map(|node| node.find_prop_by_id(id))
    }

    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
        self.nodes.iter().find_map(|node| node.find_value_by_id(id))
    }

    fn find_children_by_id(&self, id: &str) -> Option<&Children> {
        if self.id.as_deref() == Some(id) {
            Some(self)
        } else {
            self.nodes
                .iter()
                .find_map(|node| node.find_children_by_id(id))
        }
    }
}

impl BuildFromRef for Children {
    fn ref_to(query: impl Into<String>) -> Self {
        Self {
            r#ref: Some(query.into()),
            ..Self::default()
        }
    }
}

/// a validation to apply to some value or property value
#[derive(Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(Decode))]
pub enum Validation {
    /// ensure the value is of the given type
    Type(#[cfg_attr(feature = "parse-knuffel", knuffel(argument))] String),
    /// ensure the value is one of the given options
    Enum(#[cfg_attr(feature = "parse-knuffel", knuffel(arguments))] Vec<String>),
    /// ensure the value matches the given regular expression
    Pattern(#[cfg_attr(feature = "parse-knuffel", knuffel(argument))] String),
    /// ensure the value is of the given format
    Format(#[cfg_attr(feature = "parse-knuffel", knuffel(arguments))] Vec<Format>),
}

/// a format to ensure a value has
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "parse-knuffel", derive(DecodeScalar))]
pub enum Format {
    /// iso 8601 datetime string
    DateTime,
    /// iso 8601 date string
    Date,
    /// iso 8601 time string
    Time,
    /// iso 8601 duration string
    Duration,
    /// ieee 754-2008 decimal string
    Decimal,
    /// iso 4217 currency code string
    Currency,
    /// iso 3166-1 alpha-2 country code string
    Country2,
    /// iso 3166-1 alpha-3 country code string
    Country3,
    /// iso 3166-2 country subdivision code string
    CountrySubdivision,
    /// rfc 5302 email address string
    Email,
    /// rfc 6531 internationalized email address string
    IdnEmail,
    /// rfc 1132 internet hostname string
    Hostname,
    /// rfc 5890 internationalized internet hostname string
    IdnHostname,
    /// rfc 2673 ipv4 address string
    Ipv4,
    /// rfc 2373 ipv6 address string
    Ipv6,
    /// rfc 3986 uri string
    Url,
    /// rfc 3986 uri reference string
    UrlReference,
    /// rfc 3987 iri string
    Irl,
    /// rfc 3987 iri reference string
    IrlReference,
    /// rfc 6750 uri template string
    UrlTemplate,
    /// rfc 4122 uuid string
    Uuid,
    /// regular expression string
    Regex,
    /// base64 encoded string
    Base64,
    /// KDL query string
    KdlQuery,
}