use std::{io, str::FromStr};

#[derive(Debug)]
pub enum ContentType {
    Text(TextType),
    Aplication(ApplicationType),
    Image(Image),
    Any,
}

impl ContentType {
    fn to_str(&self) -> Box<str> {
        match self {
            ContentType::Text(text) => format!("text/{}", text.to_str()).into_boxed_str(),
            ContentType::Aplication(app) => {
                format!("application/{}", app.to_str()).into_boxed_str()
            }
            ContentType::Image(img) => format!("image/{}", img.to_str()).into_boxed_str(),
            ContentType::Any => "*/*".to_string().into_boxed_str(),
        }
    }
}

#[derive(Debug)]
pub enum Parameter {
    Preference(f32),
    Charset(Charset),
    Other(Box<str>, Box<str>),
}

impl Parameter {
    fn to_str(&self) -> Box<str> {
        match &self {
            Parameter::Preference(val) => format!("q={val}").into_boxed_str(),
            Parameter::Charset(ch) => format!("charset={}", ch.to_str()).into_boxed_str(),
            Parameter::Other(p, v) => format!("{p}={v}").into_boxed_str(),
        }
    }
}

#[derive(Debug)]
pub enum Charset {
    UTF8,
}

impl Charset {
    fn to_str(&self) -> &'static str {
        match self {
            Charset::UTF8 => "utf-8",
        }
    }
}

#[derive(Debug)]
pub struct Content {
    pub content_type: ContentType,
    pub parameter: Option<Vec<Parameter>>,
}

impl Content {
    pub fn to_str(&self) -> Box<str> {
        match &self.parameter {
            Some(p) => format!(
                "{}; {}",
                self.content_type.to_str(),
                p.iter()
                    .map(|par| par.to_str())
                    .collect::<Vec<_>>()
                    .join("; ")
            )
            .into_boxed_str(),
            None => self.content_type.to_str(),
        }
    }
}

impl Content {
    pub fn new(content_type: ContentType) -> Self {
        Self {
            content_type,
            parameter: None,
        }
    }

    pub fn with_params(content_type: ContentType, params: Vec<Parameter>) -> Self {
        Self {
            content_type,
            parameter: Some(params),
        }
    }

    pub fn add_parameter(&mut self, param: Parameter) {
        match &mut self.parameter {
            Some(params) => params.push(param),
            None => self.parameter = Some(vec![param]),
        }
    }

    pub fn quality(&self) -> Option<f32> {
        self.parameter.as_ref()?.iter().find_map(|p| {
            if let Parameter::Preference(q) = p {
                Some(*q)
            } else {
                None
            }
        })
    }

    pub fn charset(&self) -> Option<&Charset> {
        self.parameter.as_ref()?.iter().find_map(|p| {
            if let Parameter::Charset(cs) = p {
                Some(cs)
            } else {
                None
            }
        })
    }

    pub fn matches(&self, other: &ContentType) -> bool {
        type C = ContentType;
        match (&self.content_type, other) {
            (C::Any, _) | (_, C::Any) => true,
            (C::Text(TextType::Any), C::Text(_)) => true,
            (C::Text(_), C::Text(TextType::Any)) => true,
            (C::Aplication(ApplicationType::Any), C::Aplication(_)) => true,
            (C::Aplication(_), C::Aplication(ApplicationType::Any)) => true,
            (C::Image(Image::Any), C::Image(_)) => true,
            (C::Image(_), C::Image(Image::Any)) => true,
            (a, b) => std::mem::discriminant(a) == std::mem::discriminant(b),
        }
    }

    pub fn is_text(&self) -> bool {
        matches!(self.content_type, ContentType::Text(_))
    }

    pub fn is_application(&self) -> bool {
        matches!(self.content_type, ContentType::Aplication(_))
    }

    pub fn is_image(&self) -> bool {
        matches!(self.content_type, ContentType::Image(_))
    }

    pub fn html_utf8() -> Self {
        Self::with_params(
            ContentType::Text(TextType::Html),
            vec![Parameter::Charset(Charset::UTF8)],
        )
    }

    pub fn json_utf8() -> Self {
        Self::with_params(
            ContentType::Aplication(ApplicationType::Json),
            vec![Parameter::Charset(Charset::UTF8)],
        )
    }
}

pub fn invalid_data_error(error: &str) -> io::Error {
    io::Error::new(io::ErrorKind::InvalidData, error)
}

impl FromStr for Content {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.split(';').collect::<Vec<&str>>().as_slice() {
            [val] => Ok(Self {
                content_type: ContentType::from_str(val)?,
                parameter: None,
            }),

            [val, par @ ..] => Ok(Self {
                content_type: ContentType::from_str(val)?,
                parameter: Some(
                    par.iter()
                        .map(|p| Parameter::from_str(p))
                        .collect::<Result<Vec<_>, _>>()?,
                ),
            }),
            _ => Err(invalid_data_error("Invalid content-type")),
        }
    }
}

impl FromStr for Parameter {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.split('=').collect::<Vec<&str>>().as_slice() {
            ["q", value] => {
                let pref_val = match value.parse::<f32>() {
                    Ok(v) => Ok(v),
                    Err(_) => Err(invalid_data_error("Invalid preference")),
                }?;

                Ok(Parameter::Preference(pref_val))
            }

            ["charset", "utf-8"] => Ok(Parameter::Charset(Charset::UTF8)),

            [t, v] => Ok(Parameter::Other(
                t.to_string().into_boxed_str(),
                v.to_string().into_boxed_str(),
            )),

            _ => Err(io::Error::new(
                io::ErrorKind::InvalidData,
                "Invalid parameter",
            )),
        }
    }
}

impl FromStr for ContentType {
    type Err = io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let parts: Vec<&str> = s.split("/").collect();

        match parts.as_slice() {
            ["*", "*"] => Ok(ContentType::Any),
            ["text", "*"] => Ok(ContentType::Text(TextType::Any)),
            ["text", "html"] => Ok(ContentType::Text(TextType::Html)),
            ["text", "css"] => Ok(ContentType::Text(TextType::Css)),
            ["text", "javascript"] => Ok(ContentType::Text(TextType::Javascript)),

            ["application", "json"] => Ok(ContentType::Aplication(ApplicationType::Json)),
            ["application", "xhtml+xml"] => Ok(ContentType::Aplication(ApplicationType::XhtmlXml)),
            ["application", "xml"] => Ok(ContentType::Aplication(ApplicationType::Xml)),
            ["application", "*"] => Ok(ContentType::Aplication(ApplicationType::Any)),

            ["image", "png"] => Ok(ContentType::Image(Image::Png)),
            ["image", "jpeg"] | ["image", "jpg"] => Ok(ContentType::Image(Image::Jpeg)),
            ["image", "avif"] => Ok(ContentType::Image(Image::Avif)),
            ["image", "webp"] => Ok(ContentType::Image(Image::Webp)),
            ["image", "svg"] | ["image", "svg+xml"] => Ok(ContentType::Image(Image::Svg)),
            ["image", "*"] => Ok(ContentType::Image(Image::Any)),

            _ => {
                println!("{parts:?}");
                Err(invalid_data_error("Invalid content-type-type"))
            }
        }
    }
}

#[derive(Debug)]
pub enum Image {
    Png,
    Avif,
    Jpeg,
    Webp,
    Svg,
    Any,
}

impl Image {
    fn to_str(&self) -> &'static str {
        match self {
            Image::Png => "png",
            Image::Avif => "avif",
            Image::Jpeg => "jpeg",
            Image::Webp => "webp",
            Image::Svg => "svg",
            Image::Any => "*",
        }
    }
}

#[derive(Debug)]
pub enum TextType {
    Html,
    Css,
    Javascript,
    Any,
}

impl TextType {
    fn to_str(&self) -> &'static str {
        match self {
            TextType::Html => "html",
            TextType::Css => "css",
            TextType::Javascript => "javascript",
            TextType::Any => "*",
        }
    }
}

#[derive(Debug)]
pub enum ApplicationType {
    Json,
    Any,
    XhtmlXml,
    Xml,
}

impl ApplicationType {
    fn to_str(&self) -> &'static str {
        match self {
            ApplicationType::Json => "json",
            ApplicationType::Any => "*",
            ApplicationType::XhtmlXml => "xhtml+xml",
            ApplicationType::Xml => "xml",
        }
    }
}