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// 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.

//! Utility functions to make testing DataFusion based crates easier

use std::{env, error::Error, path::PathBuf};

/// Compares formatted output of a record batch with an expected
/// vector of strings, with the result of pretty formatting record
/// batches. This is a macro so errors appear on the correct line
///
/// Designed so that failure output can be directly copy/pasted
/// into the test code as expected results.
///
/// Expects to be called about like this:
///
/// `assert_batch_eq!(expected_lines: &[&str], batches: &[RecordBatch])`
#[macro_export]
macro_rules! assert_batches_eq {
    ($EXPECTED_LINES: expr, $CHUNKS: expr) => {
        let expected_lines: Vec<String> =
            $EXPECTED_LINES.iter().map(|&s| s.into()).collect();

        let formatted = arrow::util::pretty::pretty_format_batches($CHUNKS).unwrap();

        let actual_lines: Vec<&str> = formatted.trim().lines().collect();

        assert_eq!(
            expected_lines, actual_lines,
            "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
            expected_lines, actual_lines
        );
    };
}

/// Compares formatted output of a record batch with an expected
/// vector of strings in a way that order does not matter.
/// This is a macro so errors appear on the correct line
///
/// Designed so that failure output can be directly copy/pasted
/// into the test code as expected results.
///
/// Expects to be called about like this:
///
/// `assert_batch_sorted_eq!(expected_lines: &[&str], batches: &[RecordBatch])`
#[macro_export]
macro_rules! assert_batches_sorted_eq {
    ($EXPECTED_LINES: expr, $CHUNKS: expr) => {
        let mut expected_lines: Vec<String> =
            $EXPECTED_LINES.iter().map(|&s| s.into()).collect();

        // sort except for header + footer
        let num_lines = expected_lines.len();
        if num_lines > 3 {
            expected_lines.as_mut_slice()[2..num_lines - 1].sort_unstable()
        }

        let formatted = arrow::util::pretty::pretty_format_batches($CHUNKS).unwrap();
        // fix for windows: \r\n -->

        let mut actual_lines: Vec<&str> = formatted.trim().lines().collect();

        // sort except for header + footer
        let num_lines = actual_lines.len();
        if num_lines > 3 {
            actual_lines.as_mut_slice()[2..num_lines - 1].sort_unstable()
        }

        assert_eq!(
            expected_lines, actual_lines,
            "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
            expected_lines, actual_lines
        );
    };
}

/// Returns the arrow test data directory, which is by default stored
/// in a git submodule rooted at `testing/data`.
///
/// The default can be overridden by the optional environment
/// variable `ARROW_TEST_DATA`
///
/// panics when the directory can not be found.
///
/// Example:
/// ```
/// let testdata = datafusion::test_util::arrow_test_data();
/// let csvdata = format!("{}/csv/aggregate_test_100.csv", testdata);
/// assert!(std::path::PathBuf::from(csvdata).exists());
/// ```
pub fn arrow_test_data() -> String {
    match get_data_dir("ARROW_TEST_DATA", "../testing/data") {
        Ok(pb) => pb.display().to_string(),
        Err(err) => panic!("failed to get arrow data dir: {}", err),
    }
}

/// Returns the parquest test data directory, which is by default
/// stored in a git submodule rooted at
/// `parquest-testing/data`.
///
/// The default can be overridden by the optional environment variable
/// `PARQUET_TEST_DATA`
///
/// panics when the directory can not be found.
///
/// Example:
/// ```
/// let testdata = datafusion::test_util::parquet_test_data();
/// let filename = format!("{}/binary.parquet", testdata);
/// assert!(std::path::PathBuf::from(filename).exists());
/// ```
pub fn parquet_test_data() -> String {
    match get_data_dir("PARQUET_TEST_DATA", "../parquet-testing/data") {
        Ok(pb) => pb.display().to_string(),
        Err(err) => panic!("failed to get parquet data dir: {}", err),
    }
}

/// Returns a directory path for finding test data.
///
/// udf_env: name of an environment variable
///
/// submodule_dir: fallback path (relative to CARGO_MANIFEST_DIR)
///
///  Returns either:
/// The path referred to in `udf_env` if that variable is set and refers to a directory
/// The submodule_data directory relative to CARGO_MANIFEST_PATH
fn get_data_dir(udf_env: &str, submodule_data: &str) -> Result<PathBuf, Box<dyn Error>> {
    // Try user defined env.
    if let Ok(dir) = env::var(udf_env) {
        let trimmed = dir.trim().to_string();
        if !trimmed.is_empty() {
            let pb = PathBuf::from(trimmed);
            if pb.is_dir() {
                return Ok(pb);
            } else {
                return Err(format!(
                    "the data dir `{}` defined by env {} not found",
                    pb.display().to_string(),
                    udf_env
                )
                .into());
            }
        }
    }

    // The env is undefined or its value is trimmed to empty, let's try default dir.

    // env "CARGO_MANIFEST_DIR" is "the directory containing the manifest of your package",
    // set by `cargo run` or `cargo test`, see:
    // https://doc.rust-lang.org/cargo/reference/environment-variables.html
    let dir = env!("CARGO_MANIFEST_DIR");

    let pb = PathBuf::from(dir).join(submodule_data);
    if pb.is_dir() {
        Ok(pb)
    } else {
        Err(format!(
            "env `{}` is undefined or has empty value, and the pre-defined data dir `{}` not found\n\
             HINT: try running `git submodule update --init`",
            udf_env,
            pb.display().to_string(),
        ).into())
    }
}

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

    #[test]
    fn test_data_dir() {
        let udf_env = "get_data_dir";
        let cwd = env::current_dir().unwrap();

        let existing_pb = cwd.join("..");
        let existing = existing_pb.display().to_string();
        let existing_str = existing.as_str();

        let non_existing = cwd.join("non-existing-dir").display().to_string();
        let non_existing_str = non_existing.as_str();

        env::set_var(udf_env, non_existing_str);
        let res = get_data_dir(udf_env, existing_str);
        assert!(res.is_err());

        env::set_var(udf_env, "");
        let res = get_data_dir(udf_env, existing_str);
        assert!(res.is_ok());
        assert_eq!(res.unwrap(), existing_pb);

        env::set_var(udf_env, " ");
        let res = get_data_dir(udf_env, existing_str);
        assert!(res.is_ok());
        assert_eq!(res.unwrap(), existing_pb);

        env::set_var(udf_env, existing_str);
        let res = get_data_dir(udf_env, existing_str);
        assert!(res.is_ok());
        assert_eq!(res.unwrap(), existing_pb);

        env::remove_var(udf_env);
        let res = get_data_dir(udf_env, non_existing_str);
        assert!(res.is_err());

        let res = get_data_dir(udf_env, existing_str);
        assert!(res.is_ok());
        assert_eq!(res.unwrap(), existing_pb);
    }

    #[test]
    fn test_happy() {
        let res = arrow_test_data();
        assert!(PathBuf::from(res).is_dir());

        let res = parquet_test_data();
        assert!(PathBuf::from(res).is_dir());
    }
}