use secrecy::{ExposeSecret, SecretString};
use serde::Deserialize;
use serde_aux::field_attributes::deserialize_number_from_string;
use sqlx::{
    postgres::{PgConnectOptions, PgSslMode},
    ConnectOptions,
};
use std::{fmt::Display, str::FromStr};

#[derive(Debug, Deserialize, Clone)]
pub struct Settings {
    pub database: DatabaseSettings,
    pub application: ApplicationSettings,
}

#[derive(Debug, Deserialize, Clone)]
pub struct DatabaseSettings {
    pub username: String,
    pub password: SecretString,
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub host: String,
    pub database_name: String,
    pub require_ssl: bool,
}

#[derive(Debug, Deserialize, Clone)]
pub struct ApplicationSettings {
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub host: String,
}

#[derive(Debug, Clone)]
pub enum Environment {
    Local,
    Production,
}

pub fn get_config() -> Result<Settings, config::ConfigError> {
    let base_path = std::env::current_dir().expect("Failed to determine current directory");
    let config_directory = base_path.join("config");
    let env: Environment = std::env::var("APP_ENVIRONMENT")
        .unwrap_or_else(|_| "local".into())
        .try_into()
        .expect("Failed to parse APP_ENVIRONMENT");

    let env_filename = format!("{}.toml", &env);

    let settings = config::Config::builder()
        .add_source(config::File::from(config_directory.join("base.toml")))
        .add_source(config::File::from(config_directory.join(env_filename)))
        .add_source(
            config::Environment::with_prefix("APP")
                .prefix_separator("_")
                .separator("__"),
        )
        .build()?;
    settings.try_deserialize::<Settings>()
}

impl DatabaseSettings {
    pub fn without_db(&self) -> PgConnectOptions {
        let ssl_mode = if self.require_ssl {
            PgSslMode::Require
        } else {
            PgSslMode::Prefer
        };

        PgConnectOptions::new()
            .host(&self.host)
            .username(&self.username)
            .password(self.password.expose_secret())
            .port(self.port)
            .ssl_mode(ssl_mode)
    }

    pub fn with_db(&self) -> PgConnectOptions {
        self.without_db()
            .database(&self.database_name)
            .log_statements(tracing_log::log::LevelFilter::Trace)
    }
}

impl Display for Environment {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Environment::Local => write!(f, "local"),
            Environment::Production => write!(f, "production"),
        }
    }
}

impl TryFrom<String> for Environment {
    type Error = String;
    fn try_from(value: String) -> Result<Self, Self::Error> {
        match value.to_lowercase().as_str() {
            "local" => Ok(Self::Local),
            "production" => Ok(Self::Production),
            other => Err(format!(
                "{} is not supported environment. \
                Use either `local` or `production`.",
                other
            )),
        }
    }
}

impl FromStr for Environment {
    type Err = String;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        s.to_owned().try_into()
    }
}