// Copyright (c) Mysten Labs, Inc.
// Modifications Copyright (c) 2024 IOTA Stiftung
// SPDX-License-Identifier: Apache-2.0

extern crate core;

use std::collections::{BTreeMap, HashMap, btree_map::Entry::Occupied};

use schemars::{
    JsonSchema,
    gen::{SchemaGenerator, SchemaSettings},
    schema::SchemaObject,
};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use versions::Versioning;

/// OPEN-RPC documentation following the OpenRPC specification <https://spec.open-rpc.org>
/// The implementation is partial, only required fields and subset of optional
/// fields in the specification are implemented catered to Iota's need.
#[derive(Serialize, Deserialize, Clone)]
pub struct Project {
    openrpc: String,
    info: Info,
    methods: Vec<Method>,
    components: Components,
    // Method routing for backward compatibility, not part of the open rpc spec.
    #[serde(skip)]
    pub method_routing: HashMap<String, MethodRouting>,
}

impl Project {
    pub fn new(
        version: &str,
        title: &str,
        description: &str,
        contact_name: &str,
        url: &str,
        email: &str,
        license: &str,
        license_url: &str,
    ) -> Self {
        let openrpc = "1.2.6".to_string();
        Self {
            openrpc,
            info: Info {
                title: title.to_string(),
                description: Some(description.to_string()),
                contact: Some(Contact {
                    name: contact_name.to_string(),
                    url: Some(url.to_string()),
                    email: Some(email.to_string()),
                }),
                license: Some(License {
                    name: license.to_string(),
                    url: Some(license_url.to_string()),
                }),
                version: version.to_owned(),
                ..Default::default()
            },
            methods: vec![],
            components: Components {
                content_descriptors: Default::default(),
                schemas: Default::default(),
            },
            method_routing: Default::default(),
        }
    }

    pub fn add_module(&mut self, module: Module) {
        self.methods.extend(module.methods);

        self.methods.sort_by(|m, n| m.name.cmp(&n.name));

        self.components.schemas.extend(module.components.schemas);
        self.components
            .content_descriptors
            .extend(module.components.content_descriptors);
        self.method_routing.extend(module.method_routing);
    }

    pub fn add_examples(&mut self, mut example_provider: BTreeMap<String, Vec<ExamplePairing>>) {
        for method in &mut self.methods {
            if let Occupied(entry) = example_provider.entry(method.name.clone()) {
                let examples = entry.remove();
                let param_names = method
                    .params
                    .iter()
                    .map(|p| p.name.clone())
                    .collect::<Vec<_>>();

                // Make sure example's parameters are correct.
                for example in examples.iter() {
                    let example_param_names = example
                        .params
                        .iter()
                        .map(|param| param.name.clone())
                        .collect::<Vec<_>>();
                    assert_eq!(
                        param_names, example_param_names,
                        "Provided example parameters doesn't match the function parameters."
                    );
                }

                method.examples = examples
            } else {
                println!("No example found for method: {}", method.name);
            }
        }
    }
}

pub struct Module {
    methods: Vec<Method>,
    components: Components,
    method_routing: BTreeMap<String, MethodRouting>,
}

pub struct RpcModuleDocBuilder {
    schema_generator: SchemaGenerator,
    methods: BTreeMap<String, Method>,
    method_routing: BTreeMap<String, MethodRouting>,
    content_descriptors: BTreeMap<String, ContentDescriptor>,
}

#[derive(Serialize, Deserialize, Default, Clone)]
pub struct ContentDescriptor {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    summary: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    #[serde(skip_serializing_if = "default")]
    required: bool,
    schema: SchemaObject,
    #[serde(skip_serializing_if = "default")]
    deprecated: bool,
}

#[derive(Serialize, Deserialize, Default, Clone)]
struct Method {
    name: String,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    tags: Vec<Tag>,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    params: Vec<ContentDescriptor>,
    #[serde(skip_serializing_if = "Option::is_none")]
    result: Option<ContentDescriptor>,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    examples: Vec<ExamplePairing>,
    #[serde(skip_serializing_if = "std::ops::Not::not")]
    deprecated: bool,
}
#[derive(Clone, Debug)]
pub struct MethodRouting {
    min: Option<Versioning>,
    max: Option<Versioning>,
    pub route_to: String,
}

impl MethodRouting {
    pub fn le(version: &str, route_to: &str) -> Self {
        Self {
            min: None,
            max: Some(Versioning::new(version).unwrap()),
            route_to: route_to.to_string(),
        }
    }

    pub fn eq(version: &str, route_to: &str) -> Self {
        Self {
            min: Some(Versioning::new(version).unwrap()),
            max: Some(Versioning::new(version).unwrap()),
            route_to: route_to.to_string(),
        }
    }

    pub fn matches(&self, version: &str) -> bool {
        let version = Versioning::new(version);
        match (&version, &self.min, &self.max) {
            (Some(version), None, Some(max)) => version <= max,
            (Some(version), Some(min), None) => version >= min,
            (Some(version), Some(min), Some(max)) => version >= min && version <= max,
            (_, _, _) => false,
        }
    }
}

#[derive(Serialize, Deserialize, Default, Clone)]
pub struct ExamplePairing {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    summary: Option<String>,
    params: Vec<Example>,
    result: Example,
}

impl ExamplePairing {
    pub fn new(name: &str, params: Vec<(&str, Value)>, result: Value) -> Self {
        Self {
            name: name.to_string(),
            description: None,
            summary: None,
            params: params
                .into_iter()
                .map(|(name, value)| Example {
                    name: name.to_string(),
                    summary: None,
                    description: None,
                    value,
                })
                .collect(),
            result: Example {
                name: "Result".to_string(),
                summary: None,
                description: None,
                value: result,
            },
        }
    }
}

#[derive(Serialize, Deserialize, Default, Clone)]
pub struct Example {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    summary: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    value: Value,
}

#[derive(Serialize, Deserialize, Default, Clone)]
struct Tag {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    summary: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
}

impl Tag {
    pub fn new(name: &str) -> Self {
        Self {
            name: name.to_string(),
            summary: None,
            description: None,
        }
    }
}

#[derive(Serialize, Deserialize, Default, Clone)]
#[serde(rename_all = "camelCase")]
struct Info {
    title: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    description: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    terms_of_service: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    contact: Option<Contact>,
    #[serde(skip_serializing_if = "Option::is_none")]
    license: Option<License>,
    version: String,
}

fn default<T>(value: &T) -> bool
where
    T: Default + PartialEq,
{
    value == &T::default()
}

#[derive(Serialize, Deserialize, Default, Clone)]
struct Contact {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    url: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    email: Option<String>,
}
#[derive(Serialize, Deserialize, Default, Clone)]
struct License {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    url: Option<String>,
}

impl Default for RpcModuleDocBuilder {
    fn default() -> Self {
        let schema_generator = SchemaSettings::default()
            .with(|s| {
                s.definitions_path = "#/components/schemas/".to_string();
            })
            .into_generator();

        Self {
            schema_generator,
            methods: BTreeMap::new(),
            method_routing: Default::default(),
            content_descriptors: BTreeMap::new(),
        }
    }
}

impl RpcModuleDocBuilder {
    pub fn build(mut self) -> Module {
        Module {
            methods: self.methods.into_values().collect(),
            components: Components {
                content_descriptors: self.content_descriptors,
                schemas: self
                    .schema_generator
                    .root_schema_for::<u8>()
                    .definitions
                    .into_iter()
                    .map(|(name, schema)| (name, schema.into_object()))
                    .collect::<BTreeMap<_, _>>(),
            },
            method_routing: self.method_routing,
        }
    }

    pub fn add_method_routing(
        &mut self,
        namespace: &str,
        name: &str,
        route_to: &str,
        comparator: &str,
        version: &str,
    ) {
        let name = format!("{namespace}_{name}");
        let route_to = format!("{namespace}_{route_to}");
        let routing = match comparator {
            "<=" => MethodRouting::le(version, &route_to),
            "=" => MethodRouting::eq(version, &route_to),
            _ => panic!("Unsupported version comparator {comparator}"),
        };
        if self.method_routing.insert(name.clone(), routing).is_some() {
            panic!("Routing for method [{name}] already exists.")
        }
    }

    pub fn add_method(
        &mut self,
        namespace: &str,
        name: &str,
        params: Vec<ContentDescriptor>,
        result: Option<ContentDescriptor>,
        doc: &str,
        tag: Option<String>,
        deprecated: bool,
    ) {
        let tags = tag.map(|t| Tag::new(&t)).into_iter().collect::<Vec<_>>();
        self.add_method_internal(namespace, name, params, result, doc, tags, deprecated)
    }

    pub fn add_subscription(
        &mut self,
        namespace: &str,
        name: &str,
        params: Vec<ContentDescriptor>,
        result: Option<ContentDescriptor>,
        doc: &str,
        tag: Option<String>,
        deprecated: bool,
    ) {
        let mut tags = tag.map(|t| Tag::new(&t)).into_iter().collect::<Vec<_>>();
        tags.push(Tag::new("Websocket"));
        tags.push(Tag::new("PubSub"));
        self.add_method_internal(namespace, name, params, result, doc, tags, deprecated)
    }

    fn add_method_internal(
        &mut self,
        namespace: &str,
        name: &str,
        params: Vec<ContentDescriptor>,
        result: Option<ContentDescriptor>,
        doc: &str,
        tags: Vec<Tag>,
        deprecated: bool,
    ) {
        let description = if doc.trim().is_empty() {
            None
        } else {
            Some(doc.trim().to_string())
        };
        let name = format!("{}_{}", namespace, name);
        self.methods.insert(name.clone(), Method {
            name,
            description,
            params,
            result,
            tags,
            examples: Vec::new(),
            deprecated,
        });
    }

    pub fn create_content_descriptor<T: JsonSchema>(
        &mut self,
        name: &str,
        summary: Option<String>,
        description: Option<String>,
        required: bool,
    ) -> ContentDescriptor {
        let schema = self.schema_generator.subschema_for::<T>().into_object();
        ContentDescriptor {
            name: name.replace(' ', ""),
            summary,
            description,
            required,
            schema,
            deprecated: false,
        }
    }
}

#[derive(Serialize, Deserialize, Clone)]
#[serde(rename_all = "camelCase")]
struct Components {
    #[serde(skip_serializing_if = "BTreeMap::is_empty")]
    content_descriptors: BTreeMap<String, ContentDescriptor>,
    #[serde(skip_serializing_if = "BTreeMap::is_empty")]
    schemas: BTreeMap<String, SchemaObject>,
}

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

    #[test]
    fn test_version_matching() {
        let routing = MethodRouting::eq("1.5", "test");
        assert!(routing.matches("1.5"));
        assert!(!routing.matches("1.6"));
        assert!(!routing.matches("1.4"));

        let routing = MethodRouting::le("1.5", "test");
        assert!(routing.matches("1.5"));
        assert!(routing.matches("1.4.5"));
        assert!(routing.matches("1.4"));
        assert!(routing.matches("1.3"));

        assert!(!routing.matches("1.6"));
        assert!(!routing.matches("1.5.1"));
    }
}