mod imp;

use std::{
    sync::Arc,
};
use im;
use salsa;
use {FileId, imp::FileResolverImp};

#[derive(Debug, Default, Clone)]
pub(crate) struct State {
    pub(crate) file_map: im::HashMap<FileId, Arc<String>>,
    pub(crate) file_resolver: FileResolverImp
}

#[derive(Debug)]
pub(crate) struct Db {
    imp: imp::Db,
}

#[derive(Clone, Copy)]
pub(crate) struct QueryCtx<'a> {
    imp: &'a salsa::QueryCtx<State, imp::Data>,
}

pub(crate) struct Query<T, R>(pub(crate) u16, pub(crate) fn(QueryCtx, &T) -> R);

pub(crate) struct QueryRegistry {
    imp: imp::QueryRegistry,
}

impl Db {
    pub(crate) fn new() -> Db {
        let reg = QueryRegistry::new();
        Db { imp: imp::Db::new(reg.imp) }
    }
    pub(crate) fn state(&self) -> &State {
        self.imp.imp.ground_data()
    }
    pub(crate) fn with_changes(&self, new_state: State, changed_files: &[FileId], resolver_changed: bool) -> Db {
        Db { imp: self.imp.with_changes(new_state, changed_files, resolver_changed) }
    }
    pub(crate) fn make_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> R {
        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
        f(ctx)
    }
    pub(crate) fn trace_query<F: FnOnce(QueryCtx) -> R, R>(&self, f: F) -> (R, Vec<&'static str>) {
        let ctx = QueryCtx { imp: &self.imp.imp.query_ctx() };
        let res = f(ctx);
        let trace = self.imp.extract_trace(ctx.imp);
        (res, trace)
    }
}

impl<'a> QueryCtx<'a> {
    pub(crate) fn get<Q: imp::EvalQuery>(&self, q: Q, params: Q::Params) -> Arc<Q::Output> {
        q.get(self, params)
    }
}

pub(crate) fn file_text(ctx: QueryCtx, file_id: FileId) -> Arc<String> {
    imp::file_text(ctx, file_id)
}

pub(crate) fn file_set(ctx: QueryCtx) -> Arc<(Vec<FileId>, FileResolverImp)> {
    imp::file_set(ctx)
}
pub(crate) use self::queries::file_syntax;

mod queries {
    use std::sync::Arc;
    use libsyntax2::File;
    use libeditor::LineIndex;
    use {FileId};
    use super::{Query, QueryCtx, QueryRegistry, file_text};

    pub(crate) fn register_queries(reg: &mut QueryRegistry) {
        reg.add(FILE_SYNTAX, "FILE_SYNTAX");
        reg.add(FILE_LINES, "FILE_LINES");
    }

    pub(crate) fn file_syntax(ctx: QueryCtx, file_id: FileId) -> File {
        (&*ctx.get(FILE_SYNTAX, file_id)).clone()
    }
    pub(crate) fn file_lines(ctx: QueryCtx, file_id: FileId) -> Arc<LineIndex> {
        ctx.get(FILE_LINES, file_id)
    }

    pub(super) const FILE_SYNTAX: Query<FileId, File> = Query(16, |ctx, file_id: &FileId| {
        let text = file_text(ctx, *file_id);
        File::parse(&*text)
    });
    pub(super) const FILE_LINES: Query<FileId, LineIndex> = Query(17, |ctx, file_id: &FileId| {
        let text = file_text(ctx, *file_id);
        LineIndex::new(&*text)
    });
}

impl QueryRegistry {
    fn new() -> QueryRegistry {
        let mut reg = QueryRegistry { imp: imp::QueryRegistry::new() };
        queries::register_queries(&mut reg);
        ::module_map_db::register_queries(&mut reg);
        reg
    }
    pub(crate) fn add<Q: imp::EvalQuery>(&mut self, q: Q, name: &'static str) {
        self.imp.add(q, name)
    }
}