use super::*;
use std::{
    fs::{self, File},
    io::{self, Write},
    os::unix::fs::DirBuilderExt,
    path::PathBuf,
    process::id,
};

pub trait MultiDomain: MailStore {
    type Error;
    fn domains(&self) -> Result<Vec<String>, <Self as filesystem::MultiDomain>::Error>;
    fn add_domain(&mut self, domain: &str) -> Result<(), <Self as filesystem::MultiDomain>::Error>;
    fn remove_domain(
        &mut self,
        domain: &str,
    ) -> Result<(), <Self as filesystem::MultiDomain>::Error>;
}

#[derive(Clone, Debug)]
#[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
pub struct Filesystem {
    pub path: PathBuf,
}

impl MailStore for Filesystem {
    type Error = io::Error;

    fn users(&self) -> Vec<Mailuser> {
        todo!()
    }

    fn serves_domain(&self, domain: &str) -> bool {
        let mut path = self.path.clone();
        path.push(domain);
        path.exists()
    }

    fn has_mailuser(&self, mailuser: &str) -> bool {
        if let Some((user, host)) = mailuser.rsplit_once('@') {
            let mut path = self.path.clone();
            if host.contains('.') && !host.contains(|c: char| c.is_whitespace()) {
                path.push(host);
                path.push(user);
                return path.exists();
            }
        }
        false
    }

    fn get_folder(&self, user: &str, folder: &str) -> Option<Folder> {
        let Some((user, host)) = user.rsplit_once('@') else {
            return None;
        };
        let mut path = self.path.clone();
        path.push(host);
        path.push(user);
        path.push(folder);
        let Ok(dir) = fs::read_dir(path) else {
            return None;
        };
        let mut folder = Folder {
            name: folder.to_string(),
            messages: HashMap::new(),
        };
        dir.filter(|x| x.is_ok()).map(|x| x.unwrap()).for_each(|e| {
            if let Ok(contents) = fs::read_to_string(e.path()) {
                if let Ok(message) = contents.parse::<Message>() {
                    folder.messages.insert(message.id.clone(), message);
                }
            }
        });
        Some(folder)
    }

    fn get_message(&self, user: &str, folder: &str, title: &str) -> Option<Message> {
        self.get_folder(user, folder).and_then(|f| {
            f.messages
                .values()
                .find(|m| m.title.as_ref().map(|x| x.as_str()) == Some(title))
                .cloned()
        })
    }

    fn add_message(
        &mut self,
        user: &str,
        folder: &str,
        message: Message,
    ) -> Result<(), Self::Error> {
        let Some((user, host)) = user.rsplit_once('@') else {
            return Err(io::Error::new(io::ErrorKind::Other, "Invalid username"));
        };
        let mut path = self.path.clone();
        path.push(host);
        path.push(user);
        path.push(folder);
        path.push(&message.id);
        let mut fd = File::create(path)?;
        write!(fd, "{message}")
    }

    fn delete_message(&mut self, user: &str, folder: &str, id: &str) -> Result<(), Self::Error> {
        let Some((user, host)) = user.rsplit_once('@') else {
            return Err(io::Error::new(io::ErrorKind::Other, "Invalid username"));
        };
        let mut path = self.path.clone();
        path.push(host);
        path.push(user);
        path.push(folder);
        path.push(id);
        if path.exists() {
            fs::remove_file(&path)?;
        }
        Ok(())
    }

    fn move_message(
        &mut self,
        user: &str,
        id: &str,
        folder1: &str,
        folder2: &str,
    ) -> Result<(), io::Error> {
        let Some((user, host)) = user.rsplit_once('@') else {
            return Err(io::Error::new(io::ErrorKind::Other, "Invalid username"));
        };
        let mut infile = self.path.clone();
        infile.push(host);
        infile.push(user);
        let mut outfile = infile.clone();
        infile.push(folder1);
        infile.push(id);
        outfile.push(folder2);
        outfile.push(id);
        fs::copy(&infile, &outfile)?;
        fs::remove_file(infile)?;
        Ok(())
    }

    fn add_user(&mut self, user: &str) -> Result<(), Self::Error> {
        todo!()
    }

    fn remove_user(&mut self, user: &str) -> bool {
        todo!()
    }
}

impl MultiDomain for Filesystem {
    type Error = io::Error;

    fn domains(&self) -> Result<Vec<String>, io::Error> {
        Ok(self
            .path
            .read_dir()?
            .filter(|x| {
                if let Ok(x) = x {
                    if let Ok(t) = x.file_type() {
                        return t.is_dir();
                    }
                }
                false
            })
            .map(|x| x.unwrap().file_name().to_string_lossy().to_string())
            .collect::<Vec<String>>())
    }

    fn add_domain(&mut self, domain: &str) -> Result<(), io::Error> {
        let mut path = self.path.clone();
        path.push(domain);
        if !path.exists() {
            fs::DirBuilder::new()
                .recursive(true)
                .mode(700)
                .create(path)?;
        }
        Ok(())
    }

    fn remove_domain(&mut self, domain: &str) -> Result<(), io::Error> {
        let mut path = self.path.clone();
        path.push(domain);
        if path.exists() {
            fs::remove_dir_all(path)?;
        }
        Ok(())
    }
}