// Copyright 2018 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.

#![macro_use]
use std::collections::BTreeMap;

pub use core_traits::{Binding, Entid, TypedValue, ValueType};

use mentat_core::{DateTime, Keyword, Utc};

use super::{HasSchema, QueryInputs, QueryOutput, Queryable, RelResult, Store, Variable};

use public_traits::errors::{MentatError, Result};

pub struct QueryBuilder<'a> {
    query: String,
    values: BTreeMap<Variable, TypedValue>,
    types: BTreeMap<Variable, ValueType>,
    store: &'a mut Store,
}

impl<'a> QueryBuilder<'a> {
    pub fn new<T>(store: &'a mut Store, query: T) -> QueryBuilder<'_>
    where
        T: Into<String>,
    {
        QueryBuilder {
            query: query.into(),
            values: BTreeMap::new(),
            types: BTreeMap::new(),
            store,
        }
    }

    pub fn bind_value<T>(&mut self, var: &str, value: T) -> &mut Self
    where
        T: Into<TypedValue>,
    {
        self.values
            .insert(Variable::from_valid_name(var), value.into());
        self
    }

    pub fn bind_ref_from_kw(&mut self, var: &str, value: Keyword) -> Result<&mut Self> {
        let entid = self
            .store
            .conn()
            .current_schema()
            .get_entid(&value)
            .ok_or_else(|| MentatError::UnknownAttribute(value.to_string()))?;
        self.values.insert(
            Variable::from_valid_name(var),
            TypedValue::Ref(entid.into()),
        );
        Ok(self)
    }

    pub fn bind_ref<T>(&mut self, var: &str, value: T) -> &mut Self
    where
        T: Into<Entid>,
    {
        self.values.insert(
            Variable::from_valid_name(var),
            TypedValue::Ref(value.into()),
        );
        self
    }

    pub fn bind_long(&mut self, var: &str, value: i64) -> &mut Self {
        self.values
            .insert(Variable::from_valid_name(var), TypedValue::Long(value));
        self
    }

    pub fn bind_instant(&mut self, var: &str, value: i64) -> &mut Self {
        self.values
            .insert(Variable::from_valid_name(var), TypedValue::instant(value));

        self
    }

    pub fn bind_date_time(&mut self, var: &str, value: DateTime<Utc>) -> &mut Self {
        self.values
            .insert(Variable::from_valid_name(var), TypedValue::Instant(value));
        self
    }

    pub fn bind_type(&mut self, var: &str, value_type: ValueType) -> &mut Self {
        self.types
            .insert(Variable::from_valid_name(var), value_type);
        self
    }

    pub fn execute(&mut self) -> Result<QueryOutput> {
        let values = ::std::mem::take(&mut self.values);
        let types = ::std::mem::take(&mut self.types);
        let query_inputs = QueryInputs::new(types, values)?;
        let read = self.store.begin_read()?;
        read.q_once(&self.query, query_inputs).map_err(|e| e)
    }

    pub fn execute_scalar(&mut self) -> Result<Option<Binding>> {
        let results = self.execute()?;
        results.into_scalar().map_err(|e| e.into())
    }

    pub fn execute_coll(&mut self) -> Result<Vec<Binding>> {
        let results = self.execute()?;
        results.into_coll().map_err(|e| e.into())
    }

    pub fn execute_tuple(&mut self) -> Result<Option<Vec<Binding>>> {
        let results = self.execute()?;
        results.into_tuple().map_err(|e| e.into())
    }

    pub fn execute_rel(&mut self) -> Result<RelResult<Binding>> {
        let results = self.execute()?;
        results.into_rel().map_err(|e| e.into())
    }
}

#[cfg(test)]
mod test {
    use super::{QueryBuilder, Store, TypedValue};

    #[test]
    fn test_scalar_query() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "u" :foo/boolean true]
            [:db/add "p" :foo/boolean false]
        ]"#,
            )
            .expect("successful transaction");

        let yes = *report.tempids.get("u").expect("found it");

        let entid = QueryBuilder::new(
            &mut store,
            r#"[:find ?x .
                                                      :in ?v
                                                      :where [?x :foo/boolean ?v]]"#,
        )
        .bind_value("?v", true)
        .execute_scalar()
        .expect("ScalarResult")
        .and_then(|t| t.into_entid());
        assert_eq!(entid, Some(yes));
    }

    #[test]
    fn test_coll_query() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
            [:db/add "p" :foo/boolean false]
            [:db/add "p" :foo/long 24]
            [:db/add "u" :foo/boolean true]
            [:db/add "u" :foo/long 23]
        ]"#,
            )
            .expect("successful transaction");

        let u_yes = *report.tempids.get("u").expect("found it");
        let l_yes = *report.tempids.get("l").expect("found it");
        let n_yes = *report.tempids.get("n").expect("found it");

        let entids: Vec<i64> = QueryBuilder::new(
            &mut store,
            r#"[:find [?x ...]
                                                                 :in ?v
                                                                 :where [?x :foo/boolean ?v]]"#,
        )
        .bind_value("?v", true)
        .execute_coll()
        .expect("CollResult")
        .into_iter()
        .map(|v| v.into_entid().expect("val"))
        .collect();

        assert_eq!(entids, vec![l_yes, n_yes, u_yes]);
    }

    #[test]
    fn test_coll_query_by_row() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
            [:db/add "p" :foo/boolean false]
            [:db/add "p" :foo/long 24]
            [:db/add "u" :foo/boolean true]
            [:db/add "u" :foo/long 23]
        ]"#,
            )
            .expect("successful transaction");

        let n_yes = *report.tempids.get("n").expect("found it");

        let results = QueryBuilder::new(
            &mut store,
            r#"[:find [?x ...]
                                                        :in ?v
                                                        :where [?x :foo/boolean ?v]]"#,
        )
        .bind_value("?v", true)
        .execute_coll()
        .expect("CollResult");
        let entid = results
            .get(1)
            .and_then(|t| t.to_owned().into_entid())
            .expect("entid");

        assert_eq!(entid, n_yes);
    }

    #[test]
    fn test_tuple_query_result_by_column() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
            [:db/add "p" :foo/boolean false]
            [:db/add "p" :foo/long 24]
            [:db/add "u" :foo/boolean true]
            [:db/add "u" :foo/long 23]
        ]"#,
            )
            .expect("successful transaction");

        let n_yes = *report.tempids.get("n").expect("found it");

        let results = QueryBuilder::new(
            &mut store,
            r#"[:find [?x, ?i]
                                                        :in ?v ?i
                                                        :where [?x :foo/boolean ?v]
                                                               [?x :foo/long ?i]]"#,
        )
        .bind_value("?v", true)
        .bind_long("?i", 27)
        .execute_tuple()
        .expect("TupleResult")
        .expect("Vec<TypedValue>");
        let entid = results
            .get(0)
            .and_then(|t| t.to_owned().into_entid())
            .expect("entid");
        let long_val = results
            .get(1)
            .and_then(|t| t.to_owned().into_long())
            .expect("long");

        assert_eq!(entid, n_yes);
        assert_eq!(long_val, 27);
    }

    #[test]
    fn test_tuple_query_result_by_iter() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
            [:db/add "p" :foo/boolean false]
            [:db/add "p" :foo/long 24]
            [:db/add "u" :foo/boolean true]
            [:db/add "u" :foo/long 23]
        ]"#,
            )
            .expect("successful transaction");

        let n_yes = *report.tempids.get("n").expect("found it");

        let results: Vec<_> = QueryBuilder::new(
            &mut store,
            r#"[:find [?x, ?i]
                                                                :in ?v ?i
                                                                :where [?x :foo/boolean ?v]
                                                                       [?x :foo/long ?i]]"#,
        )
        .bind_value("?v", true)
        .bind_long("?i", 27)
        .execute_tuple()
        .expect("TupleResult")
        .unwrap_or_default();
        let entid = TypedValue::Ref(n_yes).into();
        let long_val = TypedValue::Long(27).into();

        assert_eq!(results, vec![entid, long_val]);
    }

    #[test]
    fn test_rel_query_result() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
        ]"#,
            )
            .expect("successful transaction");

        let l_yes = *report.tempids.get("l").expect("found it");
        let m_yes = *report.tempids.get("m").expect("found it");
        let n_yes = *report.tempids.get("n").expect("found it");

        #[derive(Debug, PartialEq)]
        struct Res {
            entid: i64,
            boolean: bool,
            long_val: i64,
        };

        let mut results: Vec<Res> = QueryBuilder::new(
            &mut store,
            r#"[:find ?x ?v ?i
                                                                      :where [?x :foo/boolean ?v]
                                                                             [?x :foo/long ?i]]"#,
        )
        .execute_rel()
        .expect("RelResult")
        .into_iter()
        .map(|row| Res {
            entid: row
                .get(0)
                .and_then(|t| t.to_owned().into_entid())
                .expect("entid"),
            boolean: row
                .get(1)
                .and_then(|t| t.to_owned().into_boolean())
                .expect("boolean"),
            long_val: row
                .get(2)
                .and_then(|t| t.to_owned().into_long())
                .expect("long"),
        })
        .collect();

        let res1 = results.pop().expect("res");
        assert_eq!(
            res1,
            Res {
                entid: n_yes,
                boolean: true,
                long_val: 27
            }
        );
        let res2 = results.pop().expect("res");
        assert_eq!(
            res2,
            Res {
                entid: m_yes,
                boolean: false,
                long_val: 26
            }
        );
        let res3 = results.pop().expect("res");
        assert_eq!(
            res3,
            Res {
                entid: l_yes,
                boolean: true,
                long_val: 25
            }
        );
        assert_eq!(results.pop(), None);
    }

    #[test]
    fn test_bind_ref() {
        let mut store = Store::open("").expect("store connection");
        store
            .transact(
                r#"[
            [:db/add "s" :db/ident :foo/boolean]
            [:db/add "s" :db/valueType :db.type/boolean]
            [:db/add "s" :db/cardinality :db.cardinality/one]
            [:db/add "t" :db/ident :foo/long]
            [:db/add "t" :db/valueType :db.type/long]
            [:db/add "t" :db/cardinality :db.cardinality/one]
        ]"#,
            )
            .expect("successful transaction");

        let report = store
            .transact(
                r#"[
            [:db/add "l" :foo/boolean true]
            [:db/add "l" :foo/long 25]
            [:db/add "m" :foo/boolean false]
            [:db/add "m" :foo/long 26]
            [:db/add "n" :foo/boolean true]
            [:db/add "n" :foo/long 27]
        ]"#,
            )
            .expect("successful transaction");

        let l_yes = *report.tempids.get("l").expect("found it");

        let results = QueryBuilder::new(
            &mut store,
            r#"[:find [?v ?i]
                                                        :in ?x
                                                        :where [?x :foo/boolean ?v]
                                                               [?x :foo/long ?i]]"#,
        )
        .bind_ref("?x", l_yes)
        .execute_tuple()
        .expect("TupleResult")
        .unwrap_or_default();
        assert_eq!(
            results
                .get(0)
                .and_then(|t| t.to_owned().into_boolean())
                .expect("boolean"),
            true
        );
        assert_eq!(
            results
                .get(1)
                .and_then(|t| t.to_owned().into_long())
                .expect("long"),
            25
        );
    }
}