use crate::base::component::add_base_assets;
use crate::concat_string;
use crate::core::component::AnyOp;
use crate::core::theme::all::{theme_by_short_name, THEME_DEFAULT};
use crate::core::theme::{ComponentsInRegions, ThemeRef};
use crate::html::{html, Markup};
use crate::html::{Assets, HeadScript, HeadStyles, JavaScript, StyleSheet};
use crate::locale::{LanguageIdentifier, LANGID_DEFAULT};
use crate::service::HttpRequest;
use crate::util::TypeInfo;

use std::collections::HashMap;
use std::error::Error;
use std::fmt;
use std::str::FromStr;

pub enum AssetsOp {
    LangId(&'static LanguageIdentifier),
    Theme(&'static str),
    Layout(&'static str),
    // Stylesheets.
    AddStyleSheet(StyleSheet),
    RemoveStyleSheet(&'static str),
    // Styles in head.
    AddHeadStyles(HeadStyles),
    RemoveHeadStyles(&'static str),
    // JavaScripts.
    AddJavaScript(JavaScript),
    RemoveJavaScript(&'static str),
    // Scripts in head.
    AddHeadScript(HeadScript),
    RemoveHeadScript(&'static str),
    // Add assets to properly use base components.
    AddBaseAssets,
}

#[derive(Debug)]
pub enum ParamError {
    NotFound,
    ParseError(String),
}

impl fmt::Display for ParamError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ParamError::NotFound => write!(f, "Parameter not found"),
            ParamError::ParseError(e) => write!(f, "Parse error: {}", e),
        }
    }
}

impl Error for ParamError {}

#[rustfmt::skip]
pub struct Context {
    request     : HttpRequest,
    langid      : &'static LanguageIdentifier,
    theme       : ThemeRef,
    layout      : &'static str,
    stylesheet  : Assets<StyleSheet>,                     // Stylesheets.
    headstyles  : Assets<HeadStyles>,                     // Styles in head.
    javascript  : Assets<JavaScript>,                     // JavaScripts.
    headscript  : Assets<HeadScript>,                     // Scripts in head.
    regions     : ComponentsInRegions,
    params      : HashMap<&'static str, String>,
    id_counter  : usize,
}

impl Context {
    #[rustfmt::skip]
    pub(crate) fn new(request: HttpRequest) -> Self {
        Context {
            request,
            langid      : &LANGID_DEFAULT,
            theme       : *THEME_DEFAULT,
            layout      : "default",
            stylesheet  : Assets::<StyleSheet>::new(),    // Stylesheets.
            headstyles  : Assets::<HeadStyles>::new(),    // Styles in head.
            javascript  : Assets::<JavaScript>::new(),    // JavaScripts.
            headscript  : Assets::<HeadScript>::new(),    // Scripts in head.
            regions     : ComponentsInRegions::default(),
            params      : HashMap::<&str, String>::new(),
            id_counter  : 0,
        }
    }

    #[rustfmt::skip]
    pub fn set_assets(&mut self, op: AssetsOp) -> &mut Self {
        match op {
            AssetsOp::LangId(langid) => {
                self.langid = langid;
            }
            AssetsOp::Theme(theme_name) => {
                self.theme = theme_by_short_name(theme_name).unwrap_or(*THEME_DEFAULT);
            }
            AssetsOp::Layout(layout) => {
                self.layout = layout;
            }

            // Stylesheets.
            AssetsOp::AddStyleSheet(css)     => { self.stylesheet.add(css);     }
            AssetsOp::RemoveStyleSheet(path) => { self.stylesheet.remove(path); }
            // Styles in head.
            AssetsOp::AddHeadStyles(styles)  => { self.headstyles.add(styles);  }
            AssetsOp::RemoveHeadStyles(path) => { self.headstyles.remove(path); }
            // JavaScripts.
            AssetsOp::AddJavaScript(js)      => { self.javascript.add(js);      }
            AssetsOp::RemoveJavaScript(path) => { self.javascript.remove(path); }
            // Scripts in head.
            AssetsOp::AddHeadScript(script)  => { self.headscript.add(script);  }
            AssetsOp::RemoveHeadScript(path) => { self.headscript.remove(path); }

            // Add assets to properly use base components.
            AssetsOp::AddBaseAssets => { add_base_assets(self); }
        }
        self
    }

    pub fn set_regions(&mut self, region: &'static str, op: AnyOp) -> &mut Self {
        self.regions.set_components(region, op);
        self
    }

    pub fn set_param<T: FromStr + ToString>(&mut self, key: &'static str, value: T) -> &mut Self {
        self.params.insert(key, value.to_string());
        self
    }

    pub fn remove_param(&mut self, key: &'static str) -> &mut Self {
        self.params.remove(key);
        self
    }

    /// Context GETTERS.

    pub fn request(&self) -> &HttpRequest {
        &self.request
    }

    pub fn langid(&self) -> &LanguageIdentifier {
        self.langid
    }

    pub fn theme(&self) -> ThemeRef {
        self.theme
    }

    pub fn layout(&self) -> &str {
        self.layout
    }

    pub fn regions(&self) -> &ComponentsInRegions {
        &self.regions
    }

    pub fn get_param<T: FromStr + ToString>(&self, key: &'static str) -> Result<T, ParamError> {
        match self.params.get(key) {
            Some(value) => T::from_str(value).map_err(|_| ParamError::ParseError(value.clone())),
            None => Err(ParamError::NotFound),
        }
    }

    /// Context PREPARE.

    pub(crate) fn prepare_assets(&mut self) -> Markup {
        html! {
            (self.stylesheet.prepare())                 // Stylesheets.
            (self.headstyles.prepare())                 // Styles in head.
            (self.javascript.prepare())                 // JavaScripts.
            (self.headscript.prepare())                 // Scripts in head.
        }
    }

    pub(crate) fn prepare_region(&mut self, region: impl Into<String>) -> Markup {
        self.regions
            .all_components(self.theme, region.into().as_str())
            .render(self)
    }

    // Context EXTRAS.

    pub fn required_id<T>(&mut self, id: Option<String>) -> String {
        match id {
            Some(id) => id,
            None => {
                let prefix = TypeInfo::ShortName
                    .of::<T>()
                    .trim()
                    .replace(' ', "_")
                    .to_lowercase();
                let prefix = if prefix.is_empty() {
                    "prefix".to_owned()
                } else {
                    prefix
                };
                self.id_counter += 1;
                concat_string!(prefix, "-", self.id_counter.to_string())
            }
        }
    }
}