// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

extern crate edn;

use edn::{Keyword, PlainSymbol};

use edn::query::{
    Direction, Element, FindSpec, FnArg, Limit, NonIntegerConstant, OrJoin, OrWhereClause, Order,
    Pattern, PatternNonValuePlace, PatternValuePlace, Predicate, UnifyVars, Variable, WhereClause,
};

use edn::parse::parse_query;

///! N.B., parsing a query can be done without reference to a DB.
///! Processing the parsed query into something we can work with
///! for planning involves interrogating the schema and idents in
///! the store.
///! See <https://github.com/mozilla/mentat/wiki/Querying> for more.
#[test]
fn can_parse_predicates() {
    let s = "[:find [?x ...] :where [?x _ ?y] [(< ?y 10)]]";
    let p = parse_query(s).unwrap();

    assert_eq!(
        p.find_spec,
        FindSpec::FindColl(Element::Variable(Variable::from_valid_name("?x")))
    );
    assert_eq!(
        p.where_clauses,
        vec![
            WhereClause::Pattern(Pattern {
                source: None,
                entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                attribute: PatternNonValuePlace::Placeholder,
                value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
                tx: PatternNonValuePlace::Placeholder,
            }),
            WhereClause::Pred(Predicate {
                operator: PlainSymbol::plain("<"),
                args: vec![
                    FnArg::Variable(Variable::from_valid_name("?y")),
                    FnArg::EntidOrInteger(10),
                ]
            }),
        ]
    );
}

#[test]
fn can_parse_simple_or() {
    let s = "[:find ?x . :where (or [?x _ 10] [?x _ 15])]";
    let p = parse_query(s).unwrap();

    assert_eq!(
        p.find_spec,
        FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x")))
    );
    assert_eq!(
        p.where_clauses,
        vec![WhereClause::OrJoin(OrJoin::new(
            UnifyVars::Implicit,
            vec![
                OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                    source: None,
                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                    attribute: PatternNonValuePlace::Placeholder,
                    value: PatternValuePlace::EntidOrInteger(10),
                    tx: PatternNonValuePlace::Placeholder,
                })),
                OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                    source: None,
                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                    attribute: PatternNonValuePlace::Placeholder,
                    value: PatternValuePlace::EntidOrInteger(15),
                    tx: PatternNonValuePlace::Placeholder,
                })),
            ],
        )),]
    );
}

#[test]
fn can_parse_unit_or_join() {
    let s = "[:find ?x . :where (or-join [?x] [?x _ 15])]";
    let p = parse_query(s).expect("to be able to parse find");

    assert_eq!(
        p.find_spec,
        FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x")))
    );
    assert_eq!(
        p.where_clauses,
        vec![WhereClause::OrJoin(OrJoin::new(
            UnifyVars::Explicit(std::iter::once(Variable::from_valid_name("?x")).collect()),
            vec![OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                source: None,
                entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                attribute: PatternNonValuePlace::Placeholder,
                value: PatternValuePlace::EntidOrInteger(15),
                tx: PatternNonValuePlace::Placeholder,
            })),],
        )),]
    );
}

#[test]
fn can_parse_simple_or_join() {
    let s = "[:find ?x . :where (or-join [?x] [?x _ 10] [?x _ -15])]";
    let p = parse_query(s).unwrap();

    assert_eq!(
        p.find_spec,
        FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x")))
    );
    assert_eq!(
        p.where_clauses,
        vec![WhereClause::OrJoin(OrJoin::new(
            UnifyVars::Explicit(std::iter::once(Variable::from_valid_name("?x")).collect()),
            vec![
                OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                    source: None,
                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                    attribute: PatternNonValuePlace::Placeholder,
                    value: PatternValuePlace::EntidOrInteger(10),
                    tx: PatternNonValuePlace::Placeholder,
                })),
                OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                    source: None,
                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                    attribute: PatternNonValuePlace::Placeholder,
                    value: PatternValuePlace::EntidOrInteger(-15),
                    tx: PatternNonValuePlace::Placeholder,
                })),
            ],
        )),]
    );
}

#[cfg(test)]
fn ident(ns: &str, name: &str) -> PatternNonValuePlace {
    Keyword::namespaced(ns, name).into()
}

#[test]
fn can_parse_simple_or_and_join() {
    let s = "[:find ?x . :where (or [?x _ 10] (and (or [?x :foo/bar ?y] [?x :foo/baz ?y]) [(< ?y 1)]))]";
    let p = parse_query(s).unwrap();

    assert_eq!(
        p.find_spec,
        FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x")))
    );
    assert_eq!(
        p.where_clauses,
        vec![WhereClause::OrJoin(OrJoin::new(
            UnifyVars::Implicit,
            vec![
                OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                    source: None,
                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                    attribute: PatternNonValuePlace::Placeholder,
                    value: PatternValuePlace::EntidOrInteger(10),
                    tx: PatternNonValuePlace::Placeholder,
                })),
                OrWhereClause::And(vec![
                    WhereClause::OrJoin(OrJoin::new(
                        UnifyVars::Implicit,
                        vec![
                            OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                                source: None,
                                entity: PatternNonValuePlace::Variable(Variable::from_valid_name(
                                    "?x"
                                )),
                                attribute: ident("foo", "bar"),
                                value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
                                tx: PatternNonValuePlace::Placeholder,
                            })),
                            OrWhereClause::Clause(WhereClause::Pattern(Pattern {
                                source: None,
                                entity: PatternNonValuePlace::Variable(Variable::from_valid_name(
                                    "?x"
                                )),
                                attribute: ident("foo", "baz"),
                                value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
                                tx: PatternNonValuePlace::Placeholder,
                            })),
                        ],
                    )),
                    WhereClause::Pred(Predicate {
                        operator: PlainSymbol::plain("<"),
                        args: vec![
                            FnArg::Variable(Variable::from_valid_name("?y")),
                            FnArg::EntidOrInteger(1),
                        ]
                    }),
                ],)
            ],
        )),]
    );
}

#[test]
fn can_parse_order_by() {
    let invalid = "[:find ?x :where [?x :foo/baz ?y] :order]";
    assert!(parse_query(invalid).is_err());

    // Defaults to ascending.
    let default = "[:find ?x :where [?x :foo/baz ?y] :order ?y]";
    assert_eq!(
        parse_query(default).unwrap().order,
        Some(vec![Order(
            Direction::Ascending,
            Variable::from_valid_name("?y")
        )])
    );

    let ascending = "[:find ?x :where [?x :foo/baz ?y] :order (asc ?y)]";
    assert_eq!(
        parse_query(ascending).unwrap().order,
        Some(vec![Order(
            Direction::Ascending,
            Variable::from_valid_name("?y")
        )])
    );

    let descending = "[:find ?x :where [?x :foo/baz ?y] :order (desc ?y)]";
    assert_eq!(
        parse_query(descending).unwrap().order,
        Some(vec![Order(
            Direction::Descending,
            Variable::from_valid_name("?y")
        )])
    );

    let mixed = "[:find ?x :where [?x :foo/baz ?y] :order (desc ?y) (asc ?x)]";
    assert_eq!(
        parse_query(mixed).unwrap().order,
        Some(vec![
            Order(Direction::Descending, Variable::from_valid_name("?y")),
            Order(Direction::Ascending, Variable::from_valid_name("?x"))
        ])
    );
}

#[test]
fn can_parse_limit() {
    let invalid = "[:find ?x :where [?x :foo/baz ?y] :limit]";
    assert!(parse_query(invalid).is_err());

    let zero_invalid = "[:find ?x :where [?x :foo/baz ?y] :limit 00]";
    assert!(parse_query(zero_invalid).is_err());

    let none = "[:find ?x :where [?x :foo/baz ?y]]";
    assert_eq!(parse_query(none).unwrap().limit, Limit::None);

    let one = "[:find ?x :where [?x :foo/baz ?y] :limit 1]";
    assert_eq!(parse_query(one).unwrap().limit, Limit::Fixed(1));

    let onethousand = "[:find ?x :where [?x :foo/baz ?y] :limit 1000]";
    assert_eq!(parse_query(onethousand).unwrap().limit, Limit::Fixed(1000));

    let variable_with_in = "[:find ?x :in ?limit :where [?x :foo/baz ?y] :limit ?limit]";
    assert_eq!(
        parse_query(variable_with_in).unwrap().limit,
        Limit::Variable(Variable::from_valid_name("?limit"))
    );

    let variable_with_in_used = "[:find ?x :in ?limit :where [?x :foo/baz ?limit] :limit ?limit]";
    assert_eq!(
        parse_query(variable_with_in_used).unwrap().limit,
        Limit::Variable(Variable::from_valid_name("?limit"))
    );
}

#[test]
fn can_parse_uuid() {
    let expected =
        edn::Uuid::parse_str("4cb3f828-752d-497a-90c9-b1fd516d5644").expect("valid uuid");
    let s = "[:find ?x :where [?x :foo/baz #uuid \"4cb3f828-752d-497a-90c9-b1fd516d5644\"]]";
    assert_eq!(
        parse_query(s)
            .expect("parsed")
            .where_clauses
            .pop()
            .expect("a where clause"),
        WhereClause::Pattern(
            Pattern::new(
                None,
                PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                Keyword::namespaced("foo", "baz").into(),
                PatternValuePlace::Constant(NonIntegerConstant::Uuid(expected)),
                PatternNonValuePlace::Placeholder
            )
            .expect("valid pattern")
        )
    );
}

#[test]
fn can_parse_exotic_whitespace() {
    let expected =
        edn::Uuid::parse_str("4cb3f828-752d-497a-90c9-b1fd516d5644").expect("valid uuid");
    // The query string from `can_parse_uuid`, with newlines, commas, and line comments interspersed.
    let s = r#"[:find
?x ,, :where,   ;atest
[?x :foo/baz #uuid
   "4cb3f828-752d-497a-90c9-b1fd516d5644", ;testa
,],,  ,],;"#;
    assert_eq!(
        parse_query(s)
            .expect("parsed")
            .where_clauses
            .pop()
            .expect("a where clause"),
        WhereClause::Pattern(
            Pattern::new(
                None,
                PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                Keyword::namespaced("foo", "baz").into(),
                PatternValuePlace::Constant(NonIntegerConstant::Uuid(expected)),
                PatternNonValuePlace::Placeholder
            )
            .expect("valid pattern")
        )
    );
}