use std::{
    collections::VecDeque,
    fs,
    io::{self, Write},
    path::PathBuf,
};

use log::trace;
use serde::{Deserialize, Serialize};

use super::{
    cli::Cli,
    file::{self, FileTrait},
    sharry::{self, Client, Uri},
};

#[derive(Serialize, Deserialize, Debug)]
enum FileState {
    C(file::Checked),
    U(file::Uploading),
}

impl FileState {
    fn file_name(&self) -> &str {
        match self {
            FileState::C(c) => c.get_name(),
            FileState::U(u) => u.get_name(),
        }
    }

    fn start_upload(
        self,
        http: &impl Client,
        endpoint: &str,
        alias_id: &str,
    ) -> sharry::Result<file::Uploading> {
        match self {
            FileState::C(checked) => checked.start_upload(http, endpoint, alias_id),
            FileState::U(uploading) => Ok(uploading),
        }
    }
}

#[derive(Serialize, Deserialize, Debug)]
pub struct CacheFile {
    #[serde(skip)]
    file_name: PathBuf,

    uri: Uri,
    alias_id: String,
    share_id: String,
    files: VecDeque<FileState>,
}

impl CacheFile {
    fn cache_dir() -> PathBuf {
        let dir_name = dirs_next::cache_dir()
            .expect("could not determine cache directory")
            .join("shrupl");

        trace!("cachedir: {:?}", dir_name.display());
        dir_name
    }

    fn cache_file(args: &Cli) -> PathBuf {
        let file_name = Self::cache_dir().join(format!("{}.json", args.get_hash()));

        trace!("cachefile: {:?}", file_name.display());
        file_name
    }

    pub fn try_resume(args: &Cli) -> io::Result<Self> {
        let file_name = Self::cache_file(args);

        let state: Self = {
            let file = fs::File::open(&file_name)?;
            let reader = io::BufReader::new(file);
            serde_json::from_reader(reader).map_err(io::Error::other)?
        };

        Ok(Self { file_name, ..state })
    }

    pub fn from_args(args: &Cli, share_id: String) -> Self {
        Self {
            file_name: Self::cache_file(args),
            uri: args.get_uri(),
            alias_id: args.alias.clone(),
            share_id,
            files: args.files.clone().into_iter().map(FileState::C).collect(),
        }
    }

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

    pub fn file_names(&self) -> Vec<&str> {
        self.files.iter().map(FileState::file_name).collect()
    }

    pub fn has_file(&self) -> bool {
        !self.files.is_empty()
    }

    pub fn pop_file(&mut self, http: &impl Client) -> Option<file::Uploading> {
        if let Some(state) = self.files.pop_front() {
            let endpoint = self
                .uri
                .endpoint(format!("alias/upload/{}/files/tus", self.share_id));
            Some(state.start_upload(http, &endpoint, &self.alias_id).unwrap()) // HACK unwrap
        } else {
            None
        }
    }

    pub fn push_file(&mut self, file: file::Uploading) {
        self.files.push_front(FileState::U(file));
    }

    pub fn share_notify(&self, http: &impl Client) -> sharry::Result<()> {
        let endpoint = self
            .uri
            .endpoint(format!("alias/mail/notify/{}", self.share_id));

        http.share_notify(&endpoint, &self.alias_id)
    }

    pub fn save(&self) -> io::Result<()> {
        let cache_dir = self.file_name.parent().ok_or_else(|| {
            io::Error::other(format!("orphan file {:?}", self.file_name.display()))
        })?;
        fs::create_dir_all(cache_dir)?;

        let json = serde_json::to_string_pretty(self).map_err(io::Error::other)?;
        let mut file = fs::File::create(&self.file_name)?;
        file.write_all(json.as_bytes())?;

        trace!("updated {:?}", self.file_name.display());
        Ok(())
    }

    pub fn clear(self) -> io::Result<()> {
        fs::remove_file(&self.file_name)?;

        trace!("removed {:?}", self.file_name.display());
        Ok(())
    }
}