// 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.

//! Writer properties.
//!
//! # Usage
//!
//! ```rust
//! use parquet::{
//!     basic::{Compression, Encoding},
//!     file::properties::*,
//!     schema::types::ColumnPath,
//! };
//!
//! // Create properties with default configuration.
//! let props = WriterProperties::builder().build();
//!
//! // Use properties builder to set certain options and assemble the configuration.
//! let props = WriterProperties::builder()
//!     .set_writer_version(WriterVersion::PARQUET_1_0)
//!     .set_encoding(Encoding::PLAIN)
//!     .set_column_encoding(ColumnPath::from("col1"), Encoding::DELTA_BINARY_PACKED)
//!     .set_compression(Compression::SNAPPY)
//!     .build();
//!
//! assert_eq!(props.writer_version(), WriterVersion::PARQUET_1_0);
//! assert_eq!(
//!     props.encoding(&ColumnPath::from("col1")),
//!     Some(Encoding::DELTA_BINARY_PACKED)
//! );
//! assert_eq!(
//!     props.encoding(&ColumnPath::from("col2")),
//!     Some(Encoding::PLAIN)
//! );
//! ```

use std::{collections::HashMap, rc::Rc};

use crate::basic::{Compression, Encoding};
use crate::file::metadata::KeyValue;
use crate::schema::types::ColumnPath;

const DEFAULT_PAGE_SIZE: usize = 1024 * 1024;
const DEFAULT_WRITE_BATCH_SIZE: usize = 1024;
const DEFAULT_WRITER_VERSION: WriterVersion = WriterVersion::PARQUET_1_0;
const DEFAULT_COMPRESSION: Compression = Compression::UNCOMPRESSED;
const DEFAULT_DICTIONARY_ENABLED: bool = true;
const DEFAULT_DICTIONARY_PAGE_SIZE_LIMIT: usize = DEFAULT_PAGE_SIZE;
const DEFAULT_STATISTICS_ENABLED: bool = true;
const DEFAULT_MAX_STATISTICS_SIZE: usize = 4096;
const DEFAULT_MAX_ROW_GROUP_SIZE: usize = 128 * 1024 * 1024;
const DEFAULT_CREATED_BY: &str = env!("PARQUET_CREATED_BY");

/// Parquet writer version.
///
/// Basic constant, which is not part of the Thrift definition.
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum WriterVersion {
    PARQUET_1_0,
    PARQUET_2_0,
}

impl WriterVersion {
    /// Returns writer version as `i32`.
    pub fn as_num(&self) -> i32 {
        match self {
            WriterVersion::PARQUET_1_0 => 1,
            WriterVersion::PARQUET_2_0 => 2,
        }
    }
}

/// Reference counted writer properties.
pub type WriterPropertiesPtr = Rc<WriterProperties>;

/// Writer properties.
///
/// It is created as an immutable data structure, use [`WriterPropertiesBuilder`] to
/// assemble the properties.
#[derive(Debug, Clone)]
pub struct WriterProperties {
    data_pagesize_limit: usize,
    dictionary_pagesize_limit: usize,
    write_batch_size: usize,
    max_row_group_size: usize,
    writer_version: WriterVersion,
    created_by: String,
    key_value_metadata: Option<Vec<KeyValue>>,
    default_column_properties: ColumnProperties,
    column_properties: HashMap<ColumnPath, ColumnProperties>,
}

impl WriterProperties {
    /// Returns builder for writer properties with default values.
    pub fn builder() -> WriterPropertiesBuilder {
        WriterPropertiesBuilder::with_defaults()
    }

    /// Returns data page size limit.
    pub fn data_pagesize_limit(&self) -> usize {
        self.data_pagesize_limit
    }

    /// Returns dictionary page size limit.
    pub fn dictionary_pagesize_limit(&self) -> usize {
        self.dictionary_pagesize_limit
    }

    /// Returns configured batch size for writes.
    ///
    /// When writing a batch of data, this setting allows to split it internally into
    /// smaller batches so we can better estimate the size of a page currently being
    /// written.
    pub fn write_batch_size(&self) -> usize {
        self.write_batch_size
    }

    /// Returns max size for a row group.
    pub fn max_row_group_size(&self) -> usize {
        self.max_row_group_size
    }

    /// Returns configured writer version.
    pub fn writer_version(&self) -> WriterVersion {
        self.writer_version
    }

    /// Returns `created_by` string.
    pub fn created_by(&self) -> &str {
        &self.created_by
    }

    /// Returns `key_value_metadata` KeyValue pairs.
    pub fn key_value_metadata(&self) -> &Option<Vec<KeyValue>> {
        &self.key_value_metadata
    }

    /// Returns encoding for a data page, when dictionary encoding is enabled.
    /// This is not configurable.
    #[inline]
    pub fn dictionary_data_page_encoding(&self) -> Encoding {
        // PLAIN_DICTIONARY encoding is deprecated in writer version 1.
        // Dictionary values are encoded using RLE_DICTIONARY encoding.
        Encoding::RLE_DICTIONARY
    }

    /// Returns encoding for dictionary page, when dictionary encoding is enabled.
    /// This is not configurable.
    #[inline]
    pub fn dictionary_page_encoding(&self) -> Encoding {
        // PLAIN_DICTIONARY is deprecated in writer version 1.
        // Dictionary is encoded using plain encoding.
        Encoding::PLAIN
    }

    /// Returns encoding for a column, if set.
    /// In case when dictionary is enabled, returns fallback encoding.
    ///
    /// If encoding is not set, then column writer will choose the best encoding
    /// based on the column type.
    pub fn encoding(&self, col: &ColumnPath) -> Option<Encoding> {
        self.column_properties
            .get(col)
            .and_then(|c| c.encoding())
            .or_else(|| self.default_column_properties.encoding())
    }

    /// Returns compression codec for a column.
    pub fn compression(&self, col: &ColumnPath) -> Compression {
        self.column_properties
            .get(col)
            .and_then(|c| c.compression())
            .or_else(|| self.default_column_properties.compression())
            .unwrap_or(DEFAULT_COMPRESSION)
    }

    /// Returns `true` if dictionary encoding is enabled for a column.
    pub fn dictionary_enabled(&self, col: &ColumnPath) -> bool {
        self.column_properties
            .get(col)
            .and_then(|c| c.dictionary_enabled())
            .or_else(|| self.default_column_properties.dictionary_enabled())
            .unwrap_or(DEFAULT_DICTIONARY_ENABLED)
    }

    /// Returns `true` if statistics are enabled for a column.
    pub fn statistics_enabled(&self, col: &ColumnPath) -> bool {
        self.column_properties
            .get(col)
            .and_then(|c| c.statistics_enabled())
            .or_else(|| self.default_column_properties.statistics_enabled())
            .unwrap_or(DEFAULT_STATISTICS_ENABLED)
    }

    /// Returns max size for statistics.
    /// Only applicable if statistics are enabled.
    pub fn max_statistics_size(&self, col: &ColumnPath) -> usize {
        self.column_properties
            .get(col)
            .and_then(|c| c.max_statistics_size())
            .or_else(|| self.default_column_properties.max_statistics_size())
            .unwrap_or(DEFAULT_MAX_STATISTICS_SIZE)
    }
}

/// Writer properties builder.
pub struct WriterPropertiesBuilder {
    data_pagesize_limit: usize,
    dictionary_pagesize_limit: usize,
    write_batch_size: usize,
    max_row_group_size: usize,
    writer_version: WriterVersion,
    created_by: String,
    key_value_metadata: Option<Vec<KeyValue>>,
    default_column_properties: ColumnProperties,
    column_properties: HashMap<ColumnPath, ColumnProperties>,
}

impl WriterPropertiesBuilder {
    /// Returns default state of the builder.
    fn with_defaults() -> Self {
        Self {
            data_pagesize_limit: DEFAULT_PAGE_SIZE,
            dictionary_pagesize_limit: DEFAULT_DICTIONARY_PAGE_SIZE_LIMIT,
            write_batch_size: DEFAULT_WRITE_BATCH_SIZE,
            max_row_group_size: DEFAULT_MAX_ROW_GROUP_SIZE,
            writer_version: DEFAULT_WRITER_VERSION,
            created_by: DEFAULT_CREATED_BY.to_string(),
            key_value_metadata: None,
            default_column_properties: ColumnProperties::new(),
            column_properties: HashMap::new(),
        }
    }

    /// Finalizes the configuration and returns immutable writer properties struct.
    pub fn build(self) -> WriterProperties {
        WriterProperties {
            data_pagesize_limit: self.data_pagesize_limit,
            dictionary_pagesize_limit: self.dictionary_pagesize_limit,
            write_batch_size: self.write_batch_size,
            max_row_group_size: self.max_row_group_size,
            writer_version: self.writer_version,
            created_by: self.created_by,
            key_value_metadata: self.key_value_metadata,
            default_column_properties: self.default_column_properties,
            column_properties: self.column_properties,
        }
    }

    // ----------------------------------------------------------------------
    // Writer properties related to a file

    /// Sets writer version.
    pub fn set_writer_version(mut self, value: WriterVersion) -> Self {
        self.writer_version = value;
        self
    }

    /// Sets data page size limit.
    pub fn set_data_pagesize_limit(mut self, value: usize) -> Self {
        self.data_pagesize_limit = value;
        self
    }

    /// Sets dictionary page size limit.
    pub fn set_dictionary_pagesize_limit(mut self, value: usize) -> Self {
        self.dictionary_pagesize_limit = value;
        self
    }

    /// Sets write batch size.
    pub fn set_write_batch_size(mut self, value: usize) -> Self {
        self.write_batch_size = value;
        self
    }

    /// Sets max size for a row group.
    pub fn set_max_row_group_size(mut self, value: usize) -> Self {
        self.max_row_group_size = value;
        self
    }

    /// Sets "created by" property.
    pub fn set_created_by(mut self, value: String) -> Self {
        self.created_by = value;
        self
    }

    /// Sets "key_value_metadata" property.
    pub fn set_key_value_metadata(mut self, value: Option<Vec<KeyValue>>) -> Self {
        self.key_value_metadata = value;
        self
    }

    // ----------------------------------------------------------------------
    // Setters for any column (global)

    /// Sets encoding for any column.
    ///
    /// If dictionary is not enabled, this is treated as a primary encoding for all
    /// columns. In case when dictionary is enabled for any column, this value is
    /// considered to be a fallback encoding for that column.
    ///
    /// Panics if user tries to set dictionary encoding here, regardless of dictionary
    /// encoding flag being set.
    pub fn set_encoding(mut self, value: Encoding) -> Self {
        self.default_column_properties.set_encoding(value);
        self
    }

    /// Sets compression codec for any column.
    pub fn set_compression(mut self, value: Compression) -> Self {
        self.default_column_properties.set_compression(value);
        self
    }

    /// Sets flag to enable/disable dictionary encoding for any column.
    ///
    /// Use this method to set dictionary encoding, instead of explicitly specifying
    /// encoding in `set_encoding` method.
    pub fn set_dictionary_enabled(mut self, value: bool) -> Self {
        self.default_column_properties.set_dictionary_enabled(value);
        self
    }

    /// Sets flag to enable/disable statistics for any column.
    pub fn set_statistics_enabled(mut self, value: bool) -> Self {
        self.default_column_properties.set_statistics_enabled(value);
        self
    }

    /// Sets max statistics size for any column.
    /// Applicable only if statistics are enabled.
    pub fn set_max_statistics_size(mut self, value: usize) -> Self {
        self.default_column_properties
            .set_max_statistics_size(value);
        self
    }

    // ----------------------------------------------------------------------
    // Setters for a specific column

    /// Helper method to get existing or new mutable reference of column properties.
    #[inline]
    fn get_mut_props(&mut self, col: ColumnPath) -> &mut ColumnProperties {
        self.column_properties
            .entry(col)
            .or_insert(ColumnProperties::new())
    }

    /// Sets encoding for a column.
    /// Takes precedence over globally defined settings.
    ///
    /// If dictionary is not enabled, this is treated as a primary encoding for this
    /// column. In case when dictionary is enabled for this column, either through
    /// global defaults or explicitly, this value is considered to be a fallback
    /// encoding for this column.
    ///
    /// Panics if user tries to set dictionary encoding here, regardless of dictionary
    /// encoding flag being set.
    pub fn set_column_encoding(mut self, col: ColumnPath, value: Encoding) -> Self {
        self.get_mut_props(col).set_encoding(value);
        self
    }

    /// Sets compression codec for a column.
    /// Takes precedence over globally defined settings.
    pub fn set_column_compression(mut self, col: ColumnPath, value: Compression) -> Self {
        self.get_mut_props(col).set_compression(value);
        self
    }

    /// Sets flag to enable/disable dictionary encoding for a column.
    /// Takes precedence over globally defined settings.
    pub fn set_column_dictionary_enabled(mut self, col: ColumnPath, value: bool) -> Self {
        self.get_mut_props(col).set_dictionary_enabled(value);
        self
    }

    /// Sets flag to enable/disable statistics for a column.
    /// Takes precedence over globally defined settings.
    pub fn set_column_statistics_enabled(mut self, col: ColumnPath, value: bool) -> Self {
        self.get_mut_props(col).set_statistics_enabled(value);
        self
    }

    /// Sets max size for statistics for a column.
    /// Takes precedence over globally defined settings.
    pub fn set_column_max_statistics_size(
        mut self,
        col: ColumnPath,
        value: usize,
    ) -> Self {
        self.get_mut_props(col).set_max_statistics_size(value);
        self
    }
}

/// Container for column properties that can be changed as part of writer.
///
/// If a field is `None`, it means that no specific value has been set for this column,
/// so some subsequent or default value must be used.
#[derive(Debug, Clone, PartialEq)]
struct ColumnProperties {
    encoding: Option<Encoding>,
    codec: Option<Compression>,
    dictionary_enabled: Option<bool>,
    statistics_enabled: Option<bool>,
    max_statistics_size: Option<usize>,
}

impl ColumnProperties {
    /// Initialise column properties with default values.
    fn new() -> Self {
        Self {
            encoding: None,
            codec: None,
            dictionary_enabled: None,
            statistics_enabled: None,
            max_statistics_size: None,
        }
    }

    /// Sets encoding for this column.
    ///
    /// If dictionary is not enabled, this is treated as a primary encoding for a column.
    /// In case when dictionary is enabled for a column, this value is considered to
    /// be a fallback encoding.
    ///
    /// Panics if user tries to set dictionary encoding here, regardless of dictionary
    /// encoding flag being set. Use `set_dictionary_enabled` method to enable dictionary
    /// for a column.
    fn set_encoding(&mut self, value: Encoding) {
        if value == Encoding::PLAIN_DICTIONARY || value == Encoding::RLE_DICTIONARY {
            panic!("Dictionary encoding can not be used as fallback encoding");
        }
        self.encoding = Some(value);
    }

    /// Sets compression codec for this column.
    fn set_compression(&mut self, value: Compression) {
        self.codec = Some(value);
    }

    /// Sets whether or not dictionary encoding is enabled for this column.
    fn set_dictionary_enabled(&mut self, enabled: bool) {
        self.dictionary_enabled = Some(enabled);
    }

    /// Sets whether or not statistics are enabled for this column.
    fn set_statistics_enabled(&mut self, enabled: bool) {
        self.statistics_enabled = Some(enabled);
    }

    /// Sets max size for statistics for this column.
    fn set_max_statistics_size(&mut self, value: usize) {
        self.max_statistics_size = Some(value);
    }

    /// Returns optional encoding for this column.
    fn encoding(&self) -> Option<Encoding> {
        self.encoding
    }

    /// Returns optional compression codec for this column.
    fn compression(&self) -> Option<Compression> {
        self.codec
    }

    /// Returns `Some(true)` if dictionary encoding is enabled for this column, if
    /// disabled then returns `Some(false)`. If result is `None`, then no setting has
    /// been provided.
    fn dictionary_enabled(&self) -> Option<bool> {
        self.dictionary_enabled
    }

    /// Returns `Some(true)` if statistics are enabled for this column, if disabled then
    /// returns `Some(false)`. If result is `None`, then no setting has been provided.
    fn statistics_enabled(&self) -> Option<bool> {
        self.statistics_enabled
    }

    /// Returns optional max size in bytes for statistics.
    fn max_statistics_size(&self) -> Option<usize> {
        self.max_statistics_size
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_writer_version() {
        assert_eq!(WriterVersion::PARQUET_1_0.as_num(), 1);
        assert_eq!(WriterVersion::PARQUET_2_0.as_num(), 2);
    }

    #[test]
    fn test_writer_properties_default_settings() {
        let props = WriterProperties::builder().build();
        assert_eq!(props.data_pagesize_limit(), DEFAULT_PAGE_SIZE);
        assert_eq!(
            props.dictionary_pagesize_limit(),
            DEFAULT_DICTIONARY_PAGE_SIZE_LIMIT
        );
        assert_eq!(props.write_batch_size(), DEFAULT_WRITE_BATCH_SIZE);
        assert_eq!(props.max_row_group_size(), DEFAULT_MAX_ROW_GROUP_SIZE);
        assert_eq!(props.writer_version(), DEFAULT_WRITER_VERSION);
        assert_eq!(props.created_by(), DEFAULT_CREATED_BY);
        assert_eq!(props.key_value_metadata(), &None);
        assert_eq!(props.encoding(&ColumnPath::from("col")), None);
        assert_eq!(
            props.compression(&ColumnPath::from("col")),
            DEFAULT_COMPRESSION
        );
        assert_eq!(
            props.dictionary_enabled(&ColumnPath::from("col")),
            DEFAULT_DICTIONARY_ENABLED
        );
        assert_eq!(
            props.statistics_enabled(&ColumnPath::from("col")),
            DEFAULT_STATISTICS_ENABLED
        );
        assert_eq!(
            props.max_statistics_size(&ColumnPath::from("col")),
            DEFAULT_MAX_STATISTICS_SIZE
        );
    }

    #[test]
    fn test_writer_properties_dictionary_encoding() {
        // dictionary encoding is not configurable, and it should be the same for both
        // writer version 1 and 2.
        for version in &[WriterVersion::PARQUET_1_0, WriterVersion::PARQUET_2_0] {
            let props = WriterProperties::builder()
                .set_writer_version(*version)
                .build();
            assert_eq!(props.dictionary_page_encoding(), Encoding::PLAIN);
            assert_eq!(
                props.dictionary_data_page_encoding(),
                Encoding::RLE_DICTIONARY
            );
        }
    }

    #[test]
    #[should_panic(expected = "Dictionary encoding can not be used as fallback encoding")]
    fn test_writer_properties_panic_when_plain_dictionary_is_fallback() {
        // Should panic when user specifies dictionary encoding as fallback encoding.
        WriterProperties::builder()
            .set_encoding(Encoding::PLAIN_DICTIONARY)
            .build();
    }

    #[test]
    #[should_panic(expected = "Dictionary encoding can not be used as fallback encoding")]
    fn test_writer_properties_panic_when_rle_dictionary_is_fallback() {
        // Should panic when user specifies dictionary encoding as fallback encoding.
        WriterProperties::builder()
            .set_encoding(Encoding::RLE_DICTIONARY)
            .build();
    }

    #[test]
    #[should_panic(expected = "Dictionary encoding can not be used as fallback encoding")]
    fn test_writer_properties_panic_when_dictionary_is_enabled() {
        WriterProperties::builder()
            .set_dictionary_enabled(true)
            .set_column_encoding(ColumnPath::from("col"), Encoding::RLE_DICTIONARY)
            .build();
    }

    #[test]
    #[should_panic(expected = "Dictionary encoding can not be used as fallback encoding")]
    fn test_writer_properties_panic_when_dictionary_is_disabled() {
        WriterProperties::builder()
            .set_dictionary_enabled(false)
            .set_column_encoding(ColumnPath::from("col"), Encoding::RLE_DICTIONARY)
            .build();
    }

    #[test]
    fn test_writer_properties_builder() {
        let props = WriterProperties::builder()
            // file settings
            .set_writer_version(WriterVersion::PARQUET_2_0)
            .set_data_pagesize_limit(10)
            .set_dictionary_pagesize_limit(20)
            .set_write_batch_size(30)
            .set_max_row_group_size(40)
            .set_created_by("default".to_owned())
            .set_key_value_metadata(Some(vec![KeyValue::new(
                "key".to_string(),
                "value".to_string(),
            )]))
            // global column settings
            .set_encoding(Encoding::DELTA_BINARY_PACKED)
            .set_compression(Compression::GZIP)
            .set_dictionary_enabled(false)
            .set_statistics_enabled(false)
            .set_max_statistics_size(50)
            // specific column settings
            .set_column_encoding(ColumnPath::from("col"), Encoding::RLE)
            .set_column_compression(ColumnPath::from("col"), Compression::SNAPPY)
            .set_column_dictionary_enabled(ColumnPath::from("col"), true)
            .set_column_statistics_enabled(ColumnPath::from("col"), true)
            .set_column_max_statistics_size(ColumnPath::from("col"), 123)
            .build();

        assert_eq!(props.writer_version(), WriterVersion::PARQUET_2_0);
        assert_eq!(props.data_pagesize_limit(), 10);
        assert_eq!(props.dictionary_pagesize_limit(), 20);
        assert_eq!(props.write_batch_size(), 30);
        assert_eq!(props.max_row_group_size(), 40);
        assert_eq!(props.created_by(), "default");
        assert_eq!(
            props.key_value_metadata(),
            &Some(vec![KeyValue::new("key".to_string(), "value".to_string(),)])
        );

        assert_eq!(
            props.encoding(&ColumnPath::from("a")),
            Some(Encoding::DELTA_BINARY_PACKED)
        );
        assert_eq!(props.compression(&ColumnPath::from("a")), Compression::GZIP);
        assert_eq!(props.dictionary_enabled(&ColumnPath::from("a")), false);
        assert_eq!(props.statistics_enabled(&ColumnPath::from("a")), false);
        assert_eq!(props.max_statistics_size(&ColumnPath::from("a")), 50);

        assert_eq!(
            props.encoding(&ColumnPath::from("col")),
            Some(Encoding::RLE)
        );
        assert_eq!(
            props.compression(&ColumnPath::from("col")),
            Compression::SNAPPY
        );
        assert_eq!(props.dictionary_enabled(&ColumnPath::from("col")), true);
        assert_eq!(props.statistics_enabled(&ColumnPath::from("col")), true);
        assert_eq!(props.max_statistics_size(&ColumnPath::from("col")), 123);
    }

    #[test]
    fn test_writer_properties_builder_partial_defaults() {
        let props = WriterProperties::builder()
            .set_encoding(Encoding::DELTA_BINARY_PACKED)
            .set_compression(Compression::GZIP)
            .set_column_encoding(ColumnPath::from("col"), Encoding::RLE)
            .build();

        assert_eq!(
            props.encoding(&ColumnPath::from("col")),
            Some(Encoding::RLE)
        );
        assert_eq!(
            props.compression(&ColumnPath::from("col")),
            Compression::GZIP
        );
        assert_eq!(
            props.dictionary_enabled(&ColumnPath::from("col")),
            DEFAULT_DICTIONARY_ENABLED
        );
    }
}