// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

use std::sync::Arc;

use arrow::datatypes::{DataType, Field, FieldRef, TimeUnit};
use datafusion_common::types::logical_date;
use datafusion_common::utils::take_function_args;
use datafusion_common::{Result, internal_err};
use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext};
use datafusion_expr::{
    Coercion, ColumnarValue, Expr, ExprSchemable, ReturnFieldArgs, ScalarFunctionArgs,
    ScalarUDFImpl, Signature, TypeSignatureClass, Volatility,
};

/// Returns the number of days since epoch (1970-01-01) for the given date.
/// <https://spark.apache.org/docs/latest/api/sql/index.html#unix_date>
#[derive(Debug, PartialEq, Eq, Hash)]
pub struct SparkUnixDate {
    signature: Signature,
}

impl Default for SparkUnixDate {
    fn default() -> Self {
        Self::new()
    }
}

impl SparkUnixDate {
    pub fn new() -> Self {
        Self {
            signature: Signature::coercible(
                vec![Coercion::new_exact(TypeSignatureClass::Native(
                    logical_date(),
                ))],
                Volatility::Immutable,
            ),
        }
    }
}

impl ScalarUDFImpl for SparkUnixDate {
    fn name(&self) -> &str {
        "unix_date"
    }

    fn signature(&self) -> &Signature {
        &self.signature
    }

    fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
        internal_err!("return_field_from_args should be used instead")
    }

    fn return_field_from_args(&self, args: ReturnFieldArgs) -> Result<FieldRef> {
        let nullable = args.arg_fields[0].is_nullable();
        Ok(Arc::new(Field::new(self.name(), DataType::Int32, nullable)))
    }

    fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
        internal_err!("invoke_with_args should not be called on SparkUnixDate")
    }

    fn simplify(
        &self,
        args: Vec<Expr>,
        info: &SimplifyContext,
    ) -> Result<ExprSimplifyResult> {
        let [date] = take_function_args(self.name(), args)?;
        Ok(ExprSimplifyResult::Simplified(
            date.cast_to(&DataType::Date32, info.schema())?
                .cast_to(&DataType::Int32, info.schema())?,
        ))
    }
}

#[derive(Debug, PartialEq, Eq, Hash)]
pub struct SparkUnixTimestamp {
    time_unit: TimeUnit,
    signature: Signature,
    name: &'static str,
}

impl SparkUnixTimestamp {
    pub fn new(name: &'static str, time_unit: TimeUnit) -> Self {
        Self {
            signature: Signature::coercible(
                vec![Coercion::new_exact(TypeSignatureClass::Timestamp)],
                Volatility::Immutable,
            ),
            time_unit,
            name,
        }
    }

    /// Returns the number of microseconds since epoch (1970-01-01 00:00:00 UTC) for the given timestamp.
    /// <https://spark.apache.org/docs/latest/api/sql/index.html#unix_micros>
    pub fn microseconds() -> Self {
        Self::new("unix_micros", TimeUnit::Microsecond)
    }

    /// Returns the number of milliseconds since epoch (1970-01-01 00:00:00 UTC) for the given timestamp.
    /// <https://spark.apache.org/docs/latest/api/sql/index.html#unix_millis>
    pub fn milliseconds() -> Self {
        Self::new("unix_millis", TimeUnit::Millisecond)
    }

    /// Returns the number of seconds since epoch (1970-01-01 00:00:00 UTC) for the given timestamp.
    /// <https://spark.apache.org/docs/latest/api/sql/index.html#unix_seconds>
    pub fn seconds() -> Self {
        Self::new("unix_seconds", TimeUnit::Second)
    }
}

impl ScalarUDFImpl for SparkUnixTimestamp {
    fn name(&self) -> &str {
        self.name
    }

    fn signature(&self) -> &Signature {
        &self.signature
    }

    fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
        internal_err!("return_field_from_args should be used instead")
    }

    fn return_field_from_args(&self, args: ReturnFieldArgs) -> Result<FieldRef> {
        let nullable = args.arg_fields[0].is_nullable();
        Ok(Arc::new(Field::new(self.name(), DataType::Int64, nullable)))
    }

    fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
        internal_err!("invoke_with_args should not be called on `{}`", self.name())
    }

    fn simplify(
        &self,
        args: Vec<Expr>,
        info: &SimplifyContext,
    ) -> Result<ExprSimplifyResult> {
        let [ts] = take_function_args(self.name(), args)?;
        Ok(ExprSimplifyResult::Simplified(
            ts.cast_to(
                &DataType::Timestamp(self.time_unit, Some("UTC".into())),
                info.schema(),
            )?
            .cast_to(&DataType::Int64, info.schema())?,
        ))
    }
}
