pub mod routes;

use std::{
    collections::VecDeque,
    iter::Iterator,
    sync::{
        atomic::{AtomicBool, AtomicI64, AtomicU64, Ordering},
        Arc
    }
};

use once_cell::sync::Lazy;
use rayon_core::ThreadPoolBuilder;
use rustracing_jaeger::Span;

use crate::metrics;

pub static WINDOWS_INVALID_CHARS: &str = "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F<>:\"/\\|";

pub struct ZipProgressEntry {
    temp_id: u64,
    done: AtomicBool,
    progress: AtomicU64,
    total: AtomicU64,
    delete_after: AtomicI64
}

#[derive(Debug)]
pub enum CreateNodeResult {
    InvalidName,
    InvalidParent,
    Exists(bool, i32)
}

pub static DELETE_POOL: Lazy<rayon_core::ThreadPool> = Lazy::new(|| {
    ThreadPoolBuilder::new()
        .num_threads(1)
        .thread_name(|i| format!("Delete thread {}", i))
        .build()
        .unwrap()
});
pub static ZIP_POOL: Lazy<rayon_core::ThreadPool> = Lazy::new(|| {
    ThreadPoolBuilder::new()
        .num_threads(3)
        .thread_name(|i| format!("Zip thread {}", i))
        .build()
        .unwrap()
});
pub static ZIP_TO_PROGRESS: Lazy<
    parking_lot::RwLock<std::collections::HashMap<std::collections::BTreeSet<i32>, Arc<ZipProgressEntry>>>
> = Lazy::new(|| parking_lot::RwLock::new(std::collections::HashMap::new()));

static NEXT_TEMP_ID: AtomicU64 = AtomicU64::new(0);

fn cleanup_temp_zips(span: &Span) {
    let _span = metrics::span("zipping - cleanup", span);
    let mut existing = ZIP_TO_PROGRESS.write();
    existing.retain(|_, v| {
        if Arc::strong_count(v) == 1
            && v.done.load(Ordering::Relaxed)
            && v.delete_after.load(Ordering::Relaxed) <= chrono::Utc::now().timestamp()
        {
            std::fs::remove_file(std::path::Path::new(&format!("./temp/{}", v.temp_id)))
                .expect("Failed to delete temp file");
            false
        } else {
            true
        }
    });
}

fn get_nodes_recursive(
    span: &Span,
    root: crate::db::Inode,
    db: &mut crate::db::DBConnection
) -> VecDeque<crate::db::Inode> {
    let inner_span = metrics::span("get_nodes_recursive", span);
    let mut nodes = VecDeque::from(vec![root.clone()]);
    if root.is_file {
        return nodes;
    }
    let mut nodes_to_check = VecDeque::from(vec![root]);
    while !nodes_to_check.is_empty() {
        let node = nodes_to_check.pop_front().unwrap();
        db.get_children(&inner_span, node.id).iter().for_each(|node| {
            nodes.push_back(node.clone());
            if !node.is_file {
                nodes_to_check.push_front(node.clone());
            }
        });
    }
    nodes
}

fn get_node_path(span: &Span, node: crate::db::Inode, db: &mut crate::db::DBConnection) -> VecDeque<crate::db::Inode> {
    let inner_span = metrics::span("get_node_path", span);
    let mut path = VecDeque::from(vec![node.clone()]);
    let mut node = node;
    while let Some(parent) = node.parent_id {
        node = db.get_node(&inner_span, parent).expect("Failed to get node parent");
        path.push_front(node.clone());
    }
    path
}

fn get_total_size(span: &Span, node: crate::db::Inode, db: &mut crate::db::DBConnection) -> u64 {
    let inner_span = metrics::span("get_total_size", span);
    get_nodes_recursive(&inner_span, node, db)
        .iter()
        .fold(0_u64, |acc, node| acc + node.size.unwrap_or(0) as u64)
}

pub fn get_node_and_validate(
    span: &Span,
    user: &crate::db::User,
    node: i32,
    db: &mut crate::db::DBConnection
) -> Option<crate::db::Inode> {
    let node = db.get_node(span, node)?;
    if node.owner_id != user.id {
        None
    } else {
        Some(node)
    }
}

pub fn create_node(
    span: &Span,
    name: String,
    owner: &crate::db::User,
    file: bool,
    parent: Option<i32>,
    force: bool,
    db: &mut crate::db::DBConnection
) -> Result<crate::db::Inode, CreateNodeResult> {
    let inner_span = metrics::span("create_node", span);
    if !force && (name.is_empty() || name.starts_with(' ') || name.contains(|c| {
            WINDOWS_INVALID_CHARS.contains(c)
        } || name.ends_with(' ') || name.ends_with('.') || name == "." || name == "..")) {
            return Err(CreateNodeResult::InvalidName);
        }

    if let Some(parent) = parent {
        let parent = match get_node_and_validate(&inner_span, owner, parent, db) {
            None => {
                return Err(CreateNodeResult::InvalidParent);
            }
            Some(v) => v
        };
        if parent.is_file {
            return Err(CreateNodeResult::InvalidParent);
        }
        let children = db.get_children(&inner_span, parent.id);
        for child in children {
            if child.name == name {
                return Err(CreateNodeResult::Exists(child.is_file, child.id));
            }
        }
    }

    Ok(db.create_node(&inner_span, file, name, parent, owner.id))
}

pub fn delete_node_root(span: &Span, node: &crate::db::Inode, db: &mut crate::db::DBConnection) {
    get_nodes_recursive(span, node.clone(), db).iter().rev().for_each(|node| {
        db.delete_node(span, node);
    });
}

pub fn delete_node(
    span: &Span,
    node: &crate::db::Inode,
    sender: &std::sync::mpsc::Sender<String>,
    db: &mut crate::db::DBConnection
) {
    if node.parent_id.is_none() {
        return;
    }

    for node in get_nodes_recursive(span, node.clone(), db).iter().rev() {
        sender.send(format!("Deleting {}...", generate_path(span, node, db))).unwrap();
        db.delete_node(span, node);
        sender.send(" Done \n".to_owned()).unwrap();
    }
}

pub fn generate_path(span: &Span, node: &crate::db::Inode, db: &mut crate::db::DBConnection) -> String {
    let mut path = String::new();

    get_node_path(span, node.clone(), db).iter().for_each(|node| {
        if node.parent_id.is_none() {
            path += "/";
        } else {
            path += &node.name;
            if !node.is_file {
                path += "/";
            }
        }
    });

    path
}

pub fn generate_path_dto(
    span: &Span,
    node: &crate::db::Inode,
    db: &mut crate::db::DBConnection
) -> crate::dto::responses::GetPath {
    let mut get_path = crate::dto::responses::GetPath {
        segments: Vec::new()
    };

    get_node_path(span, node.clone(), db).iter().for_each(|node| {
        if node.parent_id.is_none() {
            get_path.segments.push(crate::dto::responses::GetPathSegment {
                path: "/".to_owned(),
                node: Some(node.id)
            });
        } else {
            get_path.segments.push(crate::dto::responses::GetPathSegment {
                path: node.name.clone(),
                node: Some(node.id)
            });
            if !node.is_file {
                get_path.segments.push(crate::dto::responses::GetPathSegment {
                    path: "/".to_owned(),
                    node: None
                });
            }
        }
    });

    get_path
}