use std::collections::HashMap;
use std::error::Error;
use std::sync::OnceLock;

use crate::map::Map;
use crate::{file::FileStoredFormat, value::Value, Format};

#[cfg(feature = "toml")]
mod toml;

#[cfg(feature = "json")]
mod json;

#[cfg(feature = "yaml")]
mod yaml;

#[cfg(feature = "ini")]
mod ini;

#[cfg(feature = "ron")]
mod ron;

#[cfg(feature = "json5")]
mod json5;

/// File formats provided by the library.
///
/// Although it is possible to define custom formats using [`Format`] trait it is recommended to use `FileFormat` if possible.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub enum FileFormat {
    /// TOML (parsed with toml)
    #[cfg(feature = "toml")]
    Toml,

    /// JSON (parsed with `serde_json`)
    #[cfg(feature = "json")]
    Json,

    /// YAML (parsed with `yaml_rust2`)
    #[cfg(feature = "yaml")]
    Yaml,

    /// INI (parsed with `rust_ini`)
    #[cfg(feature = "ini")]
    Ini,

    /// RON (parsed with ron)
    #[cfg(feature = "ron")]
    Ron,

    /// JSON5 (parsed with json5)
    #[cfg(feature = "json5")]
    Json5,
}

pub(crate) fn all_extensions() -> &'static HashMap<FileFormat, Vec<&'static str>> {
    #![allow(unused_mut)] // If no features are used, there is an "unused mut" warning in `all_extensions`

    static ALL_EXTENSIONS: OnceLock<HashMap<FileFormat, Vec<&'static str>>> = OnceLock::new();
    ALL_EXTENSIONS.get_or_init(|| {
        let mut formats: HashMap<FileFormat, Vec<_>> = HashMap::new();

        #[cfg(feature = "toml")]
        formats.insert(FileFormat::Toml, vec!["toml"]);

        #[cfg(feature = "json")]
        formats.insert(FileFormat::Json, vec!["json"]);

        #[cfg(feature = "yaml")]
        formats.insert(FileFormat::Yaml, vec!["yaml", "yml"]);

        #[cfg(feature = "ini")]
        formats.insert(FileFormat::Ini, vec!["ini"]);

        #[cfg(feature = "ron")]
        formats.insert(FileFormat::Ron, vec!["ron"]);

        #[cfg(feature = "json5")]
        formats.insert(FileFormat::Json5, vec!["json5"]);

        formats
    })
}

impl FileFormat {
    pub(crate) fn extensions(&self) -> &'static [&'static str] {
        // It should not be possible for this to fail
        // A FileFormat would need to be declared without being added to the
        // all_extensions map.
        all_extensions().get(self).unwrap()
    }

    pub(crate) fn parse(
        &self,
        uri: Option<&String>,
        text: &str,
    ) -> Result<Map<String, Value>, Box<dyn Error + Send + Sync>> {
        match self {
            #[cfg(feature = "toml")]
            FileFormat::Toml => toml::parse(uri, text),

            #[cfg(feature = "json")]
            FileFormat::Json => json::parse(uri, text),

            #[cfg(feature = "yaml")]
            FileFormat::Yaml => yaml::parse(uri, text),

            #[cfg(feature = "ini")]
            FileFormat::Ini => ini::parse(uri, text),

            #[cfg(feature = "ron")]
            FileFormat::Ron => ron::parse(uri, text),

            #[cfg(feature = "json5")]
            FileFormat::Json5 => json5::parse(uri, text),

            #[cfg(all(
                not(feature = "toml"),
                not(feature = "json"),
                not(feature = "yaml"),
                not(feature = "ini"),
                not(feature = "ron"),
                not(feature = "json5"),
            ))]
            _ => unreachable!("No features are enabled, this library won't work without features"),
        }
    }
}

impl Format for FileFormat {
    fn parse(
        &self,
        uri: Option<&String>,
        text: &str,
    ) -> Result<Map<String, Value>, Box<dyn Error + Send + Sync>> {
        self.parse(uri, text)
    }
}

impl FileStoredFormat for FileFormat {
    fn file_extensions(&self) -> &'static [&'static str] {
        self.extensions()
    }
}
