use regex::{Captures, Regex};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::path::PathBuf;

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct PageData {
    pub title: String,
    pub lang: String,
    pub description: String,
    pub slug: String,
    pub html_body: String,
    pub css_src: Option<String>,
    pub js_src: Option<String>,
}

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct HtmlDoc(String);

impl HtmlDoc {
    fn load_template() -> String {
        std::fs::read_to_string(
            std::env::current_dir()
                .unwrap()
                .join("templates")
                .join("html_doc.html"),
        )
        .expect("Missing html_doc template")
    }

    pub fn from_page_data(page_data: &PageData) -> Self {
        let re = Regex::new(r#"\{[a-z]+\}"#).unwrap();

        let html = re
            .replace_all(&HtmlDoc::load_template(), |captures: &Captures| {
                let placeholder = captures.iter().next().unwrap().unwrap().as_str();
                let placeholder = placeholder[1..placeholder.len() - 1].to_owned();
                page_data.field_from_str_key(placeholder)
            })
            .to_string();

        HtmlDoc(html)
    }

    pub fn to_string(&self) -> String {
        self.0.clone()
    }
}

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct WebPage {
    pub page_data: PageData,
    pub html_doc: HtmlDoc,
}

impl PageData {
    pub fn to_web_page(&self) -> WebPage {
        WebPage {
            page_data: self.clone(),
            html_doc: HtmlDoc::from_page_data(&self),
        }
    }

    pub fn field_from_str_key(&self, key: String) -> String {
        match &key[..] {
            "title" => self.title.to_owned(),
            "lang" => self.lang.to_owned(),
            "description" => self.description.to_owned(),
            "slug" => self.slug.to_owned(),
            "body" => self.html_body.to_owned(),
            "css" => self.css_src.as_ref().unwrap_or(&String::new()).to_owned(),
            "js" => self.js_src.as_ref().unwrap_or(&String::new()).to_owned(),
            _ => String::new(),
        }
    }
}

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct PagesTree {
    pub page_data: PageData,
    pub sub_pages: Option<Vec<PagesTree>>,
}

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct WebSite {
    pages_tree: PagesTree,
    pages_index_by_url: HashMap<PathBuf, WebPage>,
}

impl WebSite {
    pub fn new(pages_tree: PagesTree) -> Self {
        let mut pages_index_by_url = HashMap::new();
        WebSite::create_index_by_url(&mut pages_index_by_url, &pages_tree, PathBuf::from("/"));

        WebSite {
            pages_tree,
            pages_index_by_url,
        }
    }

    pub fn from_json_str(json: &str) -> Self {
        WebSite::new(serde_json::from_str(json).unwrap())
    }

    fn create_index_by_url(
        index: &mut HashMap<PathBuf, WebPage>,
        pages_tree: &PagesTree,
        from_url: PathBuf,
    ) {
        let page_data = pages_tree.page_data.clone();
        let url = from_url.join(&page_data.slug);

        index.insert(url.clone(), page_data.to_web_page());

        if let Some(sub_pages) = &pages_tree.sub_pages {
            for pt in sub_pages {
                WebSite::create_index_by_url(index, pt, url.clone());
            }
        }
    }

    pub fn get_page_by_url(&self, url: &PathBuf) -> Option<&WebPage> {
        self.pages_index_by_url.get(&PathBuf::from("/").join(url))
    }
}

#[cfg(test)]
mod test_website {
    use super::*;
    const JSON_TEMPLATE: &'static str = "
{
    \"page_data\": {
        \"title\": \"Test Website\",
        \"slug\": \"\",
        \"lang\": \"en\",
        \"description\": \"A test website\",
        \"html_body\": \"<h1>Test Website</h1>\"
    },
    \"sub_pages\": [
        {
            \"page_data\": {
                \"title\": \"A sub page\",
                \"slug\": \"subpage\",
                \"lang\": \"en\",
                \"description\": \"A sub page of the testing web site\",
                \"html_body\": \"<h1>A sub page</h1>\"
            },
            \"sub_pages\": [
                {
                    \"page_data\": {
                        \"title\": \"Nested page\",
                        \"lang\": \"en\",
                        \"slug\": \"nested\",
                        \"description\": \"Nested testing page\",
                        \"html_body\": \"<h1>Nested page</h1>\"
                    } 
                }
            ]
        }
    ]
}
        ";

    #[test]
    fn test_index_pages_by_slug() {
        let website = WebSite::from_json_str(JSON_TEMPLATE);
        let root_page = website.get_page_by_url(&PathBuf::from("/"));
        assert!(root_page.is_some());
        let root_page = root_page.unwrap();
        assert_eq!(root_page.page_data.html_body, "<h1>Test Website</h1>");

        let sub_page = website.get_page_by_url(&PathBuf::from("subpage"));
        assert!(sub_page.is_some());
        let sub_page = sub_page.unwrap();
        assert_eq!(sub_page.page_data.html_body, "<h1>A sub page</h1>");

        let nested_page = website.get_page_by_url(&PathBuf::from("subpage/nested"));
        assert!(nested_page.is_some());
        let nested_page = nested_page.unwrap();
        assert_eq!(nested_page.page_data.html_body, "<h1>Nested page</h1>");
    }
}