use chrono::Local;
use regex::Regex;
use sea_orm_codegen::{
    DateTimeCrate as CodegenDateTimeCrate, EntityTransformer, EntityWriterContext, OutputFile,
    WithSerde,
};
use std::{error::Error, fmt::Display, fs, io::Write, path::Path, process::Command, str::FromStr};
use tracing_subscriber::{prelude::*, EnvFilter};
use url::Url;

use crate::{DateTimeCrate, GenerateSubcommands, MigrateSubcommands};

pub async fn run_generate_command(
    command: GenerateSubcommands,
    verbose: bool,
) -> Result<(), Box<dyn Error>> {
    match command {
        GenerateSubcommands::Entity {
            compact_format: _,
            expanded_format,
            include_hidden_tables,
            tables,
            ignore_tables,
            max_connections,
            output_dir,
            database_schema,
            database_url,
            with_serde,
            date_time_crate,
        } => {
            if verbose {
                let _ = tracing_subscriber::fmt()
                    .with_max_level(tracing::Level::DEBUG)
                    .with_test_writer()
                    .try_init();
            } else {
                let filter_layer = EnvFilter::try_new("sea_orm_codegen=info").unwrap();
                let fmt_layer = tracing_subscriber::fmt::layer()
                    .with_target(false)
                    .with_level(false)
                    .without_time();

                let _ = tracing_subscriber::registry()
                    .with(filter_layer)
                    .with(fmt_layer)
                    .try_init();
            }

            // The database should be a valid URL that can be parsed
            // protocol://username:password@host/database_name
            let url = Url::parse(&database_url)?;

            // Make sure we have all the required url components
            //
            // Missing scheme will have been caught by the Url::parse() call
            // above
            let is_sqlite = url.scheme() == "sqlite";

            let tables = match tables {
                Some(t) => t,
                _ => "".to_string(),
            };

            // Closures for filtering tables
            let filter_tables = |table: &str| -> bool {
                if !tables.is_empty() {
                    return tables.contains(&table);
                }

                true
            };

            let filter_hidden_tables = |table: &str| -> bool {
                if include_hidden_tables {
                    true
                } else {
                    !table.starts_with('_')
                }
            };

            let filter_skip_tables = |table: &String| -> bool { !ignore_tables.contains(table) };

            let database_name = if !is_sqlite {
                // The database name should be the first element of the path string
                //
                // Throwing an error if there is no database name since it might be
                // accepted by the database without it, while we're looking to dump
                // information from a particular database
                let database_name = url
                    .path_segments()
                    .unwrap_or_else(|| {
                        panic!(
                            "There is no database name as part of the url path: {}",
                            url.as_str()
                        )
                    })
                    .next()
                    .unwrap();

                // An empty string as the database name is also an error
                if database_name.is_empty() {
                    panic!(
                        "There is no database name as part of the url path: {}",
                        url.as_str()
                    );
                }

                database_name
            } else {
                Default::default()
            };

            let (schema_name, table_stmts) = match url.scheme() {
                "mysql" => {
                    use sea_schema::mysql::discovery::SchemaDiscovery;
                    use sqlx::MySql;

                    let connection = connect::<MySql>(max_connections, url.as_str()).await?;
                    let schema_discovery = SchemaDiscovery::new(connection, database_name);
                    let schema = schema_discovery.discover().await;
                    let table_stmts = schema
                        .tables
                        .into_iter()
                        .filter(|schema| filter_tables(&schema.info.name))
                        .filter(|schema| filter_hidden_tables(&schema.info.name))
                        .filter(|schema| filter_skip_tables(&schema.info.name))
                        .map(|schema| schema.write())
                        .collect();
                    (None, table_stmts)
                }
                "sqlite" => {
                    use sea_schema::sqlite::discovery::SchemaDiscovery;
                    use sqlx::Sqlite;

                    let connection = connect::<Sqlite>(max_connections, url.as_str()).await?;
                    let schema_discovery = SchemaDiscovery::new(connection);
                    let schema = schema_discovery.discover().await?;
                    let table_stmts = schema
                        .tables
                        .into_iter()
                        .filter(|schema| filter_tables(&schema.name))
                        .filter(|schema| filter_hidden_tables(&schema.name))
                        .filter(|schema| filter_skip_tables(&schema.name))
                        .map(|schema| schema.write())
                        .collect();
                    (None, table_stmts)
                }
                "postgres" | "postgresql" => {
                    use sea_schema::postgres::discovery::SchemaDiscovery;
                    use sqlx::Postgres;

                    let schema = &database_schema;
                    let connection = connect::<Postgres>(max_connections, url.as_str()).await?;
                    let schema_discovery = SchemaDiscovery::new(connection, schema);
                    let schema = schema_discovery.discover().await;
                    let table_stmts = schema
                        .tables
                        .into_iter()
                        .filter(|schema| filter_tables(&schema.info.name))
                        .filter(|schema| filter_hidden_tables(&schema.info.name))
                        .filter(|schema| filter_skip_tables(&schema.info.name))
                        .map(|schema| schema.write())
                        .collect();
                    (Some(schema.schema), table_stmts)
                }
                _ => unimplemented!("{} is not supported", url.scheme()),
            };

            let writer_context = EntityWriterContext::new(
                expanded_format,
                WithSerde::from_str(&with_serde).unwrap(),
                date_time_crate.into(),
                schema_name,
            );
            let output = EntityTransformer::transform(table_stmts)?.generate(&writer_context);

            let dir = Path::new(&output_dir);
            fs::create_dir_all(dir)?;

            for OutputFile { name, content } in output.files.iter() {
                let file_path = dir.join(name);
                let mut file = fs::File::create(file_path)?;
                file.write_all(content.as_bytes())?;
            }

            // Format each of the files
            for OutputFile { name, .. } in output.files.iter() {
                Command::new("rustfmt")
                    .arg(dir.join(name))
                    .spawn()?
                    .wait()?;
            }
        }
    }

    Ok(())
}

async fn connect<DB>(max_connections: u32, url: &str) -> Result<sqlx::Pool<DB>, Box<dyn Error>>
where
    DB: sqlx::Database,
{
    sqlx::pool::PoolOptions::<DB>::new()
        .max_connections(max_connections)
        .connect(url)
        .await
        .map_err(Into::into)
}

pub fn run_migrate_command(
    command: Option<MigrateSubcommands>,
    migration_dir: &str,
    verbose: bool,
) -> Result<(), Box<dyn Error>> {
    match command {
        Some(MigrateSubcommands::Init) => {
            let migration_dir = match migration_dir.ends_with('/') {
                true => migration_dir.to_string(),
                false => format!("{}/", migration_dir),
            };
            println!("Initializing migration directory...");
            macro_rules! write_file {
                ($filename: literal) => {
                    let fn_content = |content: String| content;
                    write_file!($filename, $filename, fn_content);
                };
                ($filename: literal, $template: literal, $fn_content: expr) => {
                    let filepath = [&migration_dir, $filename].join("");
                    println!("Creating file `{}`", filepath);
                    let path = Path::new(&filepath);
                    let prefix = path.parent().unwrap();
                    fs::create_dir_all(prefix).unwrap();
                    let mut file = fs::File::create(path)?;
                    let content = include_str!(concat!("../template/migration/", $template));
                    let content = $fn_content(content.to_string());
                    file.write_all(content.as_bytes())?;
                };
            }
            write_file!("src/lib.rs");
            write_file!("src/m20220101_000001_create_table.rs");
            write_file!("src/main.rs");
            write_file!("Cargo.toml", "_Cargo.toml", |content: String| {
                let ver = format!(
                    "^{}.{}.0",
                    env!("CARGO_PKG_VERSION_MAJOR"),
                    env!("CARGO_PKG_VERSION_MINOR")
                );
                content.replace("<sea-orm-migration-version>", &ver)
            });
            write_file!("README.md");
            println!("Done!");
            // Early exit!
            return Ok(());
        }
        Some(MigrateSubcommands::Generate { migration_name }) => {
            println!("Generating new migration...");

            // build new migration filename
            let now = Local::now();
            let migration_name = format!("m{}_{}", now.format("%Y%m%d_%H%M%S"), migration_name);

            create_new_migration(&migration_name, migration_dir)?;
            update_migrator(&migration_name, migration_dir)?;
            return Ok(());
        }
        _ => {
            let (subcommand, migration_dir, steps, verbose) = match command {
                Some(MigrateSubcommands::Fresh) => ("fresh", migration_dir, None, verbose),
                Some(MigrateSubcommands::Refresh) => ("refresh", migration_dir, None, verbose),
                Some(MigrateSubcommands::Reset) => ("reset", migration_dir, None, verbose),
                Some(MigrateSubcommands::Status) => ("status", migration_dir, None, verbose),
                Some(MigrateSubcommands::Up { num }) => ("up", migration_dir, Some(num), verbose),
                Some(MigrateSubcommands::Down { num }) => {
                    ("down", migration_dir, Some(num), verbose)
                }
                _ => ("up", migration_dir, None, verbose),
            };

            // Construct the `--manifest-path`
            let manifest_path = if migration_dir.ends_with('/') {
                format!("{}Cargo.toml", migration_dir)
            } else {
                format!("{}/Cargo.toml", migration_dir)
            };
            // Construct the arguments that will be supplied to `cargo` command
            let mut args = vec![
                "run",
                "--manifest-path",
                manifest_path.as_str(),
                "--",
                subcommand,
            ];

            let mut num: String = "".to_string();
            if let Some(steps) = steps {
                num = steps.to_string();
            }
            if !num.is_empty() {
                args.extend(["-n", num.as_str()])
            }
            if verbose {
                args.push("-v");
            }
            // Run migrator CLI on user's behalf
            println!("Running `cargo {}`", args.join(" "));
            Command::new("cargo").args(args).spawn()?.wait()?;
        }
    }

    Ok(())
}

fn create_new_migration(migration_name: &str, migration_dir: &str) -> Result<(), Box<dyn Error>> {
    let migration_filepath = Path::new(migration_dir)
        .join("src")
        .join(format!("{}.rs", &migration_name));
    println!("Creating migration file `{}`", migration_filepath.display());
    // TODO: make OS agnostic
    let migration_template =
        include_str!("../template/migration/src/m20220101_000001_create_table.rs");
    let mut migration_file = fs::File::create(migration_filepath)?;
    migration_file.write_all(migration_template.as_bytes())?;
    Ok(())
}

fn update_migrator(migration_name: &str, migration_dir: &str) -> Result<(), Box<dyn Error>> {
    let migrator_filepath = Path::new(migration_dir).join("src").join("lib.rs");
    println!(
        "Adding migration `{}` to `{}`",
        migration_name,
        migrator_filepath.display()
    );
    let migrator_content = fs::read_to_string(&migrator_filepath)?;
    let mut updated_migrator_content = migrator_content.clone();

    // create a backup of the migrator file in case something goes wrong
    let migrator_backup_filepath = migrator_filepath.with_file_name("lib.rs.bak");
    fs::copy(&migrator_filepath, &migrator_backup_filepath)?;
    let mut migrator_file = fs::File::create(&migrator_filepath)?;

    // find existing mod declarations, add new line
    let mod_regex = Regex::new(r"mod\s+(?P<name>m\d{8}_\d{6}_\w+);")?;
    let mods: Vec<_> = mod_regex.captures_iter(&migrator_content).collect();
    let mods_end = mods.last().unwrap().get(0).unwrap().end() + 1;
    updated_migrator_content.insert_str(mods_end, format!("mod {};\n", migration_name).as_str());

    // build new vector from declared migration modules
    let mut migrations: Vec<&str> = mods
        .iter()
        .map(|cap| cap.name("name").unwrap().as_str())
        .collect();
    migrations.push(migration_name);
    let mut boxed_migrations = migrations
        .iter()
        .map(|migration| format!("            Box::new({}::Migration),", migration))
        .collect::<Vec<String>>()
        .join("\n");
    boxed_migrations.push('\n');
    let boxed_migrations = format!("vec![\n{}        ]\n", boxed_migrations);
    let vec_regex = Regex::new(r"vec!\[[\s\S]+\]\n")?;
    let updated_migrator_content = vec_regex.replace(&updated_migrator_content, &boxed_migrations);

    migrator_file.write_all(updated_migrator_content.as_bytes())?;
    fs::remove_file(&migrator_backup_filepath)?;
    Ok(())
}

pub fn handle_error<E>(error: E)
where
    E: Display,
{
    eprintln!("{}", error);
    ::std::process::exit(1);
}

impl From<DateTimeCrate> for CodegenDateTimeCrate {
    fn from(date_time_crate: DateTimeCrate) -> CodegenDateTimeCrate {
        match date_time_crate {
            DateTimeCrate::Chrono => CodegenDateTimeCrate::Chrono,
            DateTimeCrate::Time => CodegenDateTimeCrate::Time,
        }
    }
}

#[cfg(test)]
mod tests {
    use clap::StructOpt;

    use super::*;
    use crate::{Cli, Commands};

    #[test]
    #[should_panic(
        expected = "called `Result::unwrap()` on an `Err` value: RelativeUrlWithoutBase"
    )]
    fn test_generate_entity_no_protocol() {
        let cli = Cli::parse_from(vec![
            "sea-orm-cli",
            "generate",
            "entity",
            "--database-url",
            "://root:root@localhost:3306/database",
        ]);

        match cli.command {
            Commands::Generate { command } => {
                smol::block_on(run_generate_command(command, cli.verbose)).unwrap();
            }
            _ => unreachable!(),
        }
    }

    #[test]
    #[should_panic(
        expected = "There is no database name as part of the url path: postgresql://root:root@localhost:3306"
    )]
    fn test_generate_entity_no_database_section() {
        let cli = Cli::parse_from(vec![
            "sea-orm-cli",
            "generate",
            "entity",
            "--database-url",
            "postgresql://root:root@localhost:3306",
        ]);

        match cli.command {
            Commands::Generate { command } => {
                smol::block_on(run_generate_command(command, cli.verbose)).unwrap();
            }
            _ => unreachable!(),
        }
    }

    #[test]
    #[should_panic(
        expected = "There is no database name as part of the url path: mysql://root:root@localhost:3306/"
    )]
    fn test_generate_entity_no_database_path() {
        let cli = Cli::parse_from(vec![
            "sea-orm-cli",
            "generate",
            "entity",
            "--database-url",
            "mysql://root:root@localhost:3306/",
        ]);

        match cli.command {
            Commands::Generate { command } => {
                smol::block_on(run_generate_command(command, cli.verbose)).unwrap();
            }
            _ => unreachable!(),
        }
    }

    #[test]
    #[should_panic(expected = "called `Result::unwrap()` on an `Err` value: PoolTimedOut")]
    fn test_generate_entity_no_password() {
        let cli = Cli::parse_from(vec![
            "sea-orm-cli",
            "generate",
            "entity",
            "--database-url",
            "mysql://root:@localhost:3306/database",
        ]);

        match cli.command {
            Commands::Generate { command } => {
                smol::block_on(run_generate_command(command, cli.verbose)).unwrap();
            }
            _ => unreachable!(),
        }
    }

    #[test]
    #[should_panic(expected = "called `Result::unwrap()` on an `Err` value: EmptyHost")]
    fn test_generate_entity_no_host() {
        let cli = Cli::parse_from(vec![
            "sea-orm-cli",
            "generate",
            "entity",
            "--database-url",
            "postgres://root:root@/database",
        ]);

        match cli.command {
            Commands::Generate { command } => {
                smol::block_on(run_generate_command(command, cli.verbose)).unwrap();
            }
            _ => unreachable!(),
        }
    }

    #[test]
    fn test_create_new_migration() {
        let migration_name = "test_name";
        let migration_dir = "/tmp/sea_orm_cli_test_new_migration/";
        fs::create_dir_all(format!("{}src", migration_dir)).unwrap();
        create_new_migration(migration_name, migration_dir).unwrap();
        let migration_filepath = Path::new(migration_dir)
            .join("src")
            .join(format!("{}.rs", migration_name));
        assert!(migration_filepath.exists());
        let migration_content = fs::read_to_string(migration_filepath).unwrap();
        assert_eq!(
            &migration_content,
            include_str!("../template/migration/src/m20220101_000001_create_table.rs")
        );
        fs::remove_dir_all("/tmp/sea_orm_cli_test_new_migration/").unwrap();
    }

    #[test]
    fn test_update_migrator() {
        let migration_name = "test_name";
        let migration_dir = "/tmp/sea_orm_cli_test_update_migrator/";
        fs::create_dir_all(format!("{}src", migration_dir)).unwrap();
        let migrator_filepath = Path::new(migration_dir).join("src").join("lib.rs");
        fs::copy("./template/migration/src/lib.rs", &migrator_filepath).unwrap();
        update_migrator(migration_name, migration_dir).unwrap();
        assert!(&migrator_filepath.exists());
        let migrator_content = fs::read_to_string(&migrator_filepath).unwrap();
        let mod_regex = Regex::new(r"mod (?P<name>\w+);").unwrap();
        let migrations: Vec<&str> = mod_regex
            .captures_iter(&migrator_content)
            .map(|cap| cap.name("name").unwrap().as_str())
            .collect();
        assert_eq!(migrations.len(), 2);
        assert_eq!(
            *migrations.first().unwrap(),
            "m20220101_000001_create_table"
        );
        assert_eq!(migrations.last().unwrap(), &migration_name);
        let boxed_regex = Regex::new(r"Box::new\((?P<name>\S+)::Migration\)").unwrap();
        let migrations: Vec<&str> = boxed_regex
            .captures_iter(&migrator_content)
            .map(|cap| cap.name("name").unwrap().as_str())
            .collect();
        assert_eq!(migrations.len(), 2);
        assert_eq!(
            *migrations.first().unwrap(),
            "m20220101_000001_create_table"
        );
        assert_eq!(migrations.last().unwrap(), &migration_name);
        fs::remove_dir_all("/tmp/sea_orm_cli_test_update_migrator/").unwrap();
    }
}