use std::{fmt, io, path::PathBuf, time::Duration};

use console::style;
use indicatif::{ProgressBar, ProgressStyle};
use log::{debug, trace};
use serde::{Deserialize, Serialize};

use super::{
    cli::Cli,
    file::FileTrait,
    savedstate::SavedState,
    sharry::{self, Client, ClientError},
};

#[derive(Serialize, Deserialize)]
pub struct AppState {
    #[serde(skip)]
    progress: Option<ProgressBar>,
    #[serde(skip)]
    buffer: Vec<u8>,

    inner: SavedState,
}

impl fmt::Debug for AppState {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("AppState")
            .field("inner", &self.inner)
            .finish()
    }
}

impl AppState {
    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
    }

    fn new(chunk_size: usize, inner: SavedState) -> Self {
        Self {
            progress: None,
            buffer: vec![0; chunk_size * 1024 * 1024],
            inner,
        }
    }

    pub fn try_resume(args: &Cli) -> Option<Self> {
        let file_name = Self::cache_file(args);
        let inner = SavedState::load(&file_name)
            .inspect_err(|e| debug!("could not resume from {:?}: {e}", file_name.display()))
            .ok()?;

        Some(Self::new(args.chunk_size, inner))
    }

    pub fn from_args(args: &Cli, http: &impl Client) -> sharry::Result<Self> {
        let uri = args.get_uri();
        let share_id = http.share_create(
            &uri.endpoint("alias/upload/new"),
            &args.alias,
            args.get_share_request(),
        )?;

        Ok(Self::new(
            args.chunk_size,
            SavedState::new(
                Self::cache_file(&args),
                uri,
                args.alias.clone(),
                share_id,
                &args.files,
            ),
        ))
    }

    pub fn file_names(&self) -> Vec<&str> {
        self.inner.file_names()
    }

    pub fn upload_chunk(&mut self, http: &impl Client) -> sharry::Result<Option<()>> {
        let Some(mut uploading) = self.inner.pop_file(http) else {
            return Ok(None);
        };

        debug!("{uploading} chunk {}", self.buffer.len());

        // Initialize or fetch the existing ProgressBar
        let bar = &*self.progress.get_or_insert_with(|| {
            // Create a new bar with style
            let bar = ProgressBar::new(uploading.get_size())
                .with_style(
                    ProgressStyle::with_template(&format!(
                        concat!(
                            "{{msg:.yellow}}: {{bar:50.cyan/blue}} ",
                            "{{binary_bytes:.magenta}}{}{{binary_total_bytes:.magenta}} ",
                            "({{eta}})",
                        ),
                        style("/").magenta(),
                    ))
                    .unwrap(),
                )
                .with_message(uploading.get_name().to_owned())
                .with_position(uploading.get_offset());

            bar.enable_steady_tick(Duration::from_millis(100));
            bar
        });

        let chunk = uploading
            .read(&mut self.buffer)
            .map_err(ClientError::from)?;
        if chunk.get_length() == 0 {
            return Err(ClientError::req_err("wtf"));
        }

        http.file_patch(
            chunk.get_patch_uri(),
            &self.alias_id,
            chunk.get_offset(),
            chunk.get_data(),
        )?;

        match uploading.check_eof() {
            Ok(uploading) => {
                bar.set_position(uploading.get_offset());
                self.inner.push_file(uploading);
                Ok(Some(()))
            }
            Err(path) => {
                debug!("Finished {:?}!", path.display());
                bar.finish();
                self.progress = None;

                let endpoint = self
                    .uri
                    .endpoint(format!("alias/mail/notify/{}", self.share_id));
                http.share_notify(&endpoint, &self.alias_id).unwrap(); // HACK unwrap

                Ok(self.inner.has_file().then_some(()))
            }
        }
    }

    pub fn save(&self) -> io::Result<()> {
        self.inner.save()
    }

    pub fn clear(self) -> io::Result<()> {
        self.inner.clear()
    }
}