use itertools::Itertools;
use crate::data::RPC;

pub const JSON_INNER_IMPLS: &[(&str, &str)] = &[
    ("std::string", "String"),
    ("std::int8_t", "Int"),
    ("std::int16_t", "Int"),
    ("std::int32_t", "Int"),
    ("std::int64_t", "Int64"),
    ("std::uint8_t", "Uint"),
    ("std::uint16_t", "Uint"),
    ("std::uint32_t", "Uint"),
    ("std::uint64_t", "Uint64"),
    ("bool", "Bool"),
    ("std::float_t", "Double"),
    ("std::double_t", "Double")
];

pub fn ty_to_str(ty: &crate::data::Types) -> String {
    use crate::data::Types;
    match ty {
        Types::String => "std::string".into(),
        Types::Bool => "bool".into(),
        Types::F32 => "std::float_t".into(),
        Types::F64 => "std::double_t".into(),
        Types::I8 => "std::int8_t".into(),
        Types::I16 => "std::int16_t".into(),
        Types::I32 => "std::int32_t".into(),
        Types::I64 => "std::int64_t".into(),
        Types::U8 => "std::uint8_t".into(),
        Types::U16 => "std::uint16_t".into(),
        Types::U32 => "std::uint32_t".into(),
        Types::U64 => "std::uint64_t".into(),
        Types::Named(name) => name.into(),
        Types::Optional(inner) => format!("std::optional<{}>", ty_to_str(inner)),
        Types::Array(inner) => format!("std::vector<{}>", ty_to_str(inner)),
        Types::Generic(name, types) =>
            format!("{}<{}>", name, types.iter().map(|ty| ty_to_str(ty)).join(", "))
    }
}

pub fn get_struct_generics(s: &crate::data::StructTy) -> String {
    if s.generic_names.is_empty() {
        "".into()
    } else {
        format!("template<{}>\n", generics_brace_inner_typename(s))
    }
}

pub fn generics_brace_inner_typename(s: &crate::data::StructTy) -> String {
    s.generic_names.iter().map(|n| String::from("typename ") + n).join(", ")
}

pub fn generics_brace(s: &crate::data::StructTy) -> String {
    if s.generic_names.is_empty() {
        "".into()
    } else {
        format!("<{}>", generics_brace_inner(s))
    }
}

pub fn generics_brace_inner(s: &crate::data::StructTy) -> String {
    s.generic_names.iter().join(", ")
}

pub fn method_args(method: &crate::data::MethodTy) -> String {
    method.args.iter()
        .map(|arg| format!("{} &&{}", ty_to_str(&arg.ty), arg.name))
        .chain(method.ret_stream.then(|| format!("MRPCStream<{}>&&", ty_to_str(method.ret.as_ref().unwrap()))))
        .join(", ")
}

pub fn method_ret(method: &crate::data::MethodTy) -> String {
    if method.ret_stream || method.ret.is_none() {
        "void".into()
    } else {
        ty_to_str(method.ret.as_ref().unwrap())
    }
}

pub fn call_args(method: &crate::data::MethodTy) -> String {
    method.args.iter()
        .map(|arg| format!("std::move({})", arg.name))
        .chain(method.ret_stream.then_some(String::from("std::move(__stream)")))
        .join(", ")
}

pub fn streams_required(rpc: &RPC) -> Vec<String> {
    let mut streams = std::collections::HashSet::new();
    for s in &rpc.services {
        for m in &s.methods {
            if m.ret_stream {
                streams.insert(ty_to_str(m.ret.as_ref().unwrap()));
            }
        }
    }
    streams.into_iter().collect()
}

pub fn gen(file_base_name: &std::path::PathBuf, rpc: &RPC) {
    let header_name = file_base_name.with_extension("hxx");
    let h = std::fs::File::create(&header_name).unwrap();
    let header_name = header_name.file_name().unwrap().to_str().unwrap();
    let c = std::fs::File::create(file_base_name.with_extension("cxx")).unwrap();
    crate::templates::cpp_server_hxx(h, rpc).unwrap();
    crate::templates::cpp_server_cxx(c, header_name, rpc).unwrap();
}