//! # Config settings definitions
//! To load config values from TOML file path, it can be provided via command-line arguments <br>
//! It use [serde](https://serde.rs/) via [`load_from_file`]
//

use serde::de::DeserializeOwned;
use serde::{Deserialize, Serialize}; // ,Deserializer,Serializer};
use std::io::{Error, ErrorKind, Result};

use crate::{defs::CliSettings, CFG_FILE_EXTENSION, DEFAULT_INPUT_PATH, DEFAULT_REG_EXP};

fn default_config_input() -> String {
    String::from("input.txt")
}
fn default_config_output() -> String {
    String::from("")
}
fn default_config_overwrite() -> bool {
    true
}
fn default_config_be_quiet() -> bool {
    false
}
fn default_config_reg_exp() -> String {
    String::from(DEFAULT_REG_EXP)
}
fn default_config_targets() -> Vec<ConfigTarget> {
    vec![ConfigTarget::default()]
}
/// Settings for each target metric defined in **config path**
/// **config.toml** content example:
/// ```toml
/// be_quiet = false
/// [[targets]]
/// input = "input.txt"
///
/// [[targets]]
/// input = "input_2.txt"
/// ```
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ConfigTarget {
    #[serde(default = "default_config_input")]
    pub input: String,
    #[serde(default = "default_config_output")]
    pub output: String,
    #[serde(default = "default_config_overwrite")]
    pub out_overwrite: bool,
    #[serde(default = "default_config_reg_exp")]
    pub reg_exp: String,
}

impl Default for ConfigTarget {
    fn default() -> Self {
        Self {
            input: String::from(DEFAULT_INPUT_PATH),
            output: String::from(""),
            out_overwrite: true,
            reg_exp: String::from(DEFAULT_REG_EXP),
        }
    }
}
/// Config Settings with target metric settings [`ConfigTarget`]
/// **config.toml** content example:
/// ```toml
/// be_quiet = false
/// [[targets]]
/// input = "input.txt"
///
/// [[targets]]
/// input = "input_2.txt"
/// ```
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Config {
    #[serde(default = "default_config_be_quiet")]
    pub be_quiet: bool,
    #[serde(default = "default_config_targets")]
    pub targets: Vec<ConfigTarget>,
}
impl Default for Config {
    fn default() -> Self {
        Self {
            be_quiet: false,
            targets: vec![ConfigTarget::default()],
        }
    }
}
impl Config {
    // To override [`Config`] values with [`CliSettings`] provided via command line arguments and loaded via [`parse_args`]
    pub fn add_cli_settings(&self, cli_settings: CliSettings) -> Self {
        let be_quiet = if let Some(be_quiet) = cli_settings.be_quiet {
            be_quiet
        } else {
            self.be_quiet
        };
        let targets = if let Some(input) = cli_settings.input {
            let mut target = ConfigTarget {
                input,
                ..Default::default()
            };
            if let Some(output) = cli_settings.output {
                target.output = output
            }
            vec![target]
        } else {
            self.targets.to_owned()
        };
        Self { be_quiet, targets }
    }
}
/// To load config settings and **Deserialize** content to [`Config`] struct <br>
/// It use **T** as generic, allowing to load from a file to a **T** type
/// It use **fs::read_to_string** as it is expecting short files size, no need to buffers.
pub fn load_from_file<T: DeserializeOwned>(file_cfg: &str) -> Result<T> {
    let file_path = if file_cfg.contains(CFG_FILE_EXTENSION) {
        file_cfg.to_string()
    } else {
        format!("{}{}", file_cfg, CFG_FILE_EXTENSION)
    };
    let config_content = match std::fs::read_to_string(&file_path) {
        Ok(cfgcontent) => cfgcontent,
        Err(e) => {
            return Err(Error::new(
                ErrorKind::InvalidInput,
                format!("Error read {}: {}", &file_path, e),
            ))
        }
    };
    let item_cfg = match toml::from_str::<T>(&config_content) {
        Ok(cfg) => cfg,
        Err(e) => {
            return Err(Error::new(
                ErrorKind::InvalidInput,
                format!("Error loading config {}: {}", &file_path, e),
            ))
        }
    };
    Ok(item_cfg)
}