// 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.

//! Execution functions

use std::io::prelude::*;
use std::io::BufReader;
use std::time::Instant;
use std::{fs::File, sync::Arc};

use crate::print_format::PrintFormat;
use crate::{
    command::{Command, OutputFormat},
    helper::{unescape_input, CliHelper},
    object_storage::{
        get_gcs_object_store_builder, get_oss_object_store_builder,
        get_s3_object_store_builder,
    },
    print_options::{MaxRows, PrintOptions},
};

use datafusion::common::{exec_datafusion_err, plan_datafusion_err};
use datafusion::datasource::listing::ListingTableUrl;
use datafusion::datasource::physical_plan::is_plan_streaming;
use datafusion::error::{DataFusionError, Result};
use datafusion::logical_expr::{CreateExternalTable, DdlStatement, LogicalPlan};
use datafusion::physical_plan::{collect, execute_stream};
use datafusion::prelude::SessionContext;
use datafusion::sql::{parser::DFParser, sqlparser::dialect::dialect_from_str};

use object_store::ObjectStore;
use rustyline::error::ReadlineError;
use rustyline::Editor;
use tokio::signal;
use url::Url;

/// run and execute SQL statements and commands, against a context with the given print options
pub async fn exec_from_commands(
    ctx: &mut SessionContext,
    commands: Vec<String>,
    print_options: &PrintOptions,
) -> Result<()> {
    for sql in commands {
        exec_and_print(ctx, print_options, sql).await?;
    }

    Ok(())
}

/// run and execute SQL statements and commands from a file, against a context with the given print options
pub async fn exec_from_lines(
    ctx: &mut SessionContext,
    reader: &mut BufReader<File>,
    print_options: &PrintOptions,
) -> Result<()> {
    let mut query = "".to_owned();

    for line in reader.lines() {
        match line {
            Ok(line) if line.starts_with("--") => {
                continue;
            }
            Ok(line) => {
                let line = line.trim_end();
                query.push_str(line);
                if line.ends_with(';') {
                    match exec_and_print(ctx, print_options, query).await {
                        Ok(_) => {}
                        Err(err) => eprintln!("{err}"),
                    }
                    query = "".to_owned();
                } else {
                    query.push('\n');
                }
            }
            _ => {
                break;
            }
        }
    }

    // run the left over query if the last statement doesn't contain ‘;’
    // ignore if it only consists of '\n'
    if query.contains(|c| c != '\n') {
        exec_and_print(ctx, print_options, query).await?;
    }

    Ok(())
}

pub async fn exec_from_files(
    ctx: &mut SessionContext,
    files: Vec<String>,
    print_options: &PrintOptions,
) -> Result<()> {
    let files = files
        .into_iter()
        .map(|file_path| File::open(file_path).unwrap())
        .collect::<Vec<_>>();

    for file in files {
        let mut reader = BufReader::new(file);
        exec_from_lines(ctx, &mut reader, print_options).await?;
    }

    Ok(())
}

/// run and execute SQL statements and commands against a context with the given print options
pub async fn exec_from_repl(
    ctx: &mut SessionContext,
    print_options: &mut PrintOptions,
) -> rustyline::Result<()> {
    let mut rl = Editor::new()?;
    rl.set_helper(Some(CliHelper::new(
        &ctx.task_ctx().session_config().options().sql_parser.dialect,
    )));
    rl.load_history(".history").ok();

    loop {
        match rl.readline("❯ ") {
            Ok(line) if line.starts_with('\\') => {
                rl.add_history_entry(line.trim_end())?;
                let command = line.split_whitespace().collect::<Vec<_>>().join(" ");
                if let Ok(cmd) = &command[1..].parse::<Command>() {
                    match cmd {
                        Command::Quit => break,
                        Command::OutputFormat(subcommand) => {
                            if let Some(subcommand) = subcommand {
                                if let Ok(command) = subcommand.parse::<OutputFormat>() {
                                    if let Err(e) = command.execute(print_options).await {
                                        eprintln!("{e}")
                                    }
                                } else {
                                    eprintln!(
                                        "'\\{}' is not a valid command",
                                        &line[1..]
                                    );
                                }
                            } else {
                                println!("Output format is {:?}.", print_options.format);
                            }
                        }
                        _ => {
                            if let Err(e) = cmd.execute(ctx, print_options).await {
                                eprintln!("{e}")
                            }
                        }
                    }
                } else {
                    eprintln!("'\\{}' is not a valid command", &line[1..]);
                }
            }
            Ok(line) => {
                rl.add_history_entry(line.trim_end())?;
                tokio::select! {
                    res = exec_and_print(ctx, print_options, line) => match res {
                        Ok(_) => {}
                        Err(err) => eprintln!("{err}"),
                    },
                    _ = signal::ctrl_c() => {
                        println!("^C");
                        continue
                    },
                }
                // dialect might have changed
                rl.helper_mut().unwrap().set_dialect(
                    &ctx.task_ctx().session_config().options().sql_parser.dialect,
                );
            }
            Err(ReadlineError::Interrupted) => {
                println!("^C");
                continue;
            }
            Err(ReadlineError::Eof) => {
                println!("\\q");
                break;
            }
            Err(err) => {
                eprintln!("Unknown error happened {:?}", err);
                break;
            }
        }
    }

    rl.save_history(".history")
}

async fn exec_and_print(
    ctx: &mut SessionContext,
    print_options: &PrintOptions,
    sql: String,
) -> Result<()> {
    let now = Instant::now();
    let sql = unescape_input(&sql)?;
    let task_ctx = ctx.task_ctx();
    let dialect = &task_ctx.session_config().options().sql_parser.dialect;
    let dialect = dialect_from_str(dialect).ok_or_else(|| {
        plan_datafusion_err!(
            "Unsupported SQL dialect: {dialect}. Available dialects: \
                 Generic, MySQL, PostgreSQL, Hive, SQLite, Snowflake, Redshift, \
                 MsSQL, ClickHouse, BigQuery, Ansi."
        )
    })?;

    let statements = DFParser::parse_sql_with_dialect(&sql, dialect.as_ref())?;
    for statement in statements {
        let mut plan = ctx.state().statement_to_plan(statement).await?;

        // For plans like `Explain` ignore `MaxRows` option and always display all rows
        let should_ignore_maxrows = matches!(
            plan,
            LogicalPlan::Explain(_)
                | LogicalPlan::DescribeTable(_)
                | LogicalPlan::Analyze(_)
        );

        // Note that cmd is a mutable reference so that create_external_table function can remove all
        // datafusion-cli specific options before passing through to datafusion. Otherwise, datafusion
        // will raise Configuration errors.
        if let LogicalPlan::Ddl(DdlStatement::CreateExternalTable(cmd)) = &mut plan {
            create_external_table(ctx, cmd).await?;
        }

        let df = ctx.execute_logical_plan(plan).await?;
        let physical_plan = df.create_physical_plan().await?;

        if is_plan_streaming(&physical_plan)? {
            let stream = execute_stream(physical_plan, task_ctx.clone())?;
            print_options.print_stream(stream, now).await?;
        } else {
            let mut print_options = print_options.clone();
            if should_ignore_maxrows {
                print_options.maxrows = MaxRows::Unlimited;
            }
            if print_options.format == PrintFormat::Automatic {
                print_options.format = PrintFormat::Table;
            }
            let results = collect(physical_plan, task_ctx.clone()).await?;
            print_options.print_batches(&results, now)?;
        }
    }

    Ok(())
}

async fn create_external_table(
    ctx: &SessionContext,
    cmd: &mut CreateExternalTable,
) -> Result<()> {
    let table_path = ListingTableUrl::parse(&cmd.location)?;
    let scheme = table_path.scheme();
    let url: &Url = table_path.as_ref();

    // registering the cloud object store dynamically using cmd.options
    let store = match scheme {
        "s3" => {
            let builder = get_s3_object_store_builder(url, cmd).await?;
            Arc::new(builder.build()?) as Arc<dyn ObjectStore>
        }
        "oss" => {
            let builder = get_oss_object_store_builder(url, cmd)?;
            Arc::new(builder.build()?) as Arc<dyn ObjectStore>
        }
        "gs" | "gcs" => {
            let builder = get_gcs_object_store_builder(url, cmd)?;
            Arc::new(builder.build()?) as Arc<dyn ObjectStore>
        }
        _ => {
            // for other types, try to get from the object_store_registry
            ctx.runtime_env()
                .object_store_registry
                .get_store(url)
                .map_err(|_| {
                    exec_datafusion_err!("Unsupported object store scheme: {}", scheme)
                })?
        }
    };

    ctx.runtime_env().register_object_store(url, store);

    Ok(())
}

#[cfg(test)]
mod tests {
    use std::str::FromStr;

    use super::*;
    use datafusion::common::plan_err;
    use datafusion_common::{file_options::StatementOptions, FileTypeWriterOptions};

    async fn create_external_table_test(location: &str, sql: &str) -> Result<()> {
        let ctx = SessionContext::new();
        let mut plan = ctx.state().create_logical_plan(sql).await?;

        if let LogicalPlan::Ddl(DdlStatement::CreateExternalTable(cmd)) = &mut plan {
            create_external_table(&ctx, cmd).await?;
            let options: Vec<_> = cmd
                .options
                .iter()
                .map(|(k, v)| (k.clone(), v.clone()))
                .collect();
            let statement_options = StatementOptions::new(options);
            let file_type =
                datafusion_common::FileType::from_str(cmd.file_type.as_str())?;

            let _file_type_writer_options = FileTypeWriterOptions::build(
                &file_type,
                ctx.state().config_options(),
                &statement_options,
            )?;
        } else {
            return plan_err!("LogicalPlan is not a CreateExternalTable");
        }

        ctx.runtime_env()
            .object_store(ListingTableUrl::parse(location)?)?;

        Ok(())
    }

    #[tokio::test]
    async fn create_object_store_table_s3() -> Result<()> {
        let access_key_id = "fake_access_key_id";
        let secret_access_key = "fake_secret_access_key";
        let region = "fake_us-east-2";
        let session_token = "fake_session_token";
        let location = "s3://bucket/path/file.parquet";

        // Missing region, use object_store defaults
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET
            OPTIONS('access_key_id' '{access_key_id}', 'secret_access_key' '{secret_access_key}') LOCATION '{location}'");
        create_external_table_test(location, &sql).await?;

        // Should be OK
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET
            OPTIONS('access_key_id' '{access_key_id}', 'secret_access_key' '{secret_access_key}', 'region' '{region}', 'session_token' '{session_token}') LOCATION '{location}'");
        create_external_table_test(location, &sql).await?;

        Ok(())
    }

    #[tokio::test]
    async fn create_object_store_table_oss() -> Result<()> {
        let access_key_id = "fake_access_key_id";
        let secret_access_key = "fake_secret_access_key";
        let endpoint = "fake_endpoint";
        let location = "oss://bucket/path/file.parquet";

        // Should be OK
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET
            OPTIONS('access_key_id' '{access_key_id}', 'secret_access_key' '{secret_access_key}', 'endpoint' '{endpoint}') LOCATION '{location}'");
        create_external_table_test(location, &sql).await?;

        Ok(())
    }

    #[tokio::test]
    async fn create_object_store_table_gcs() -> Result<()> {
        let service_account_path = "fake_service_account_path";
        let service_account_key =
            "{\"private_key\": \"fake_private_key.pem\",\"client_email\":\"fake_client_email\", \"private_key_id\":\"id\"}";
        let application_credentials_path = "fake_application_credentials_path";
        let location = "gcs://bucket/path/file.parquet";

        // for service_account_path
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET
            OPTIONS('service_account_path' '{service_account_path}') LOCATION '{location}'");
        let err = create_external_table_test(location, &sql)
            .await
            .unwrap_err();
        assert!(err.to_string().contains("os error 2"));

        // for service_account_key
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET OPTIONS('service_account_key' '{service_account_key}') LOCATION '{location}'");
        let err = create_external_table_test(location, &sql)
            .await
            .unwrap_err()
            .to_string();
        assert!(err.contains("No RSA key found in pem file"), "{err}");

        // for application_credentials_path
        let sql = format!("CREATE EXTERNAL TABLE test STORED AS PARQUET
            OPTIONS('application_credentials_path' '{application_credentials_path}') LOCATION '{location}'");
        let err = create_external_table_test(location, &sql)
            .await
            .unwrap_err();
        assert!(err.to_string().contains("os error 2"));

        Ok(())
    }

    #[tokio::test]
    async fn create_external_table_local_file() -> Result<()> {
        let location = "path/to/file.parquet";

        // Ensure that local files are also registered
        let sql =
            format!("CREATE EXTERNAL TABLE test STORED AS PARQUET LOCATION '{location}'");
        create_external_table_test(location, &sql).await.unwrap();

        Ok(())
    }
}