use client_network::{
    MerkleNode, MerkleTree, NetworkCommand, NetworkEvent, NodeHash, filename_to_string,
    node_hash_to_hex_string,
};
use crossbeam_channel::{Receiver, Sender};
use egui::{
    Align, Align2, Button, CentralPanel, CollapsingHeader, Context, Id, LayerId, Layout, Order,
    Popup, ScrollArea, SidePanel, TopBottomPanel, Ui, ViewportCommand,
};
use std::collections::HashMap;

enum ServerStatus {
    Loading,
    NotConnected,
    Connected,
}

// --- Main Application Struct ---
pub struct P2PClientApp {
    // Communication channels
    network_cmd_tx: Sender<NetworkCommand>,
    network_event_rx: Receiver<NetworkEvent>,

    // GUI State
    status_message: String,
    known_peers: Vec<String>,
    connect_address_input: String,
    connect_server_name_input: String,

    // Key: Parent Directory Hash (String), Value: List of children FileNode
    loaded_fs: HashMap<String, MerkleTree>,

    // Current peer tree displayed
    active_peer: Option<String>,

    server_status: ServerStatus,
}

impl P2PClientApp {
    pub fn new(cmd_tx: Sender<NetworkCommand>, event_rx: Receiver<NetworkEvent>) -> Self {
        let (root_hash, tree_content) = MerkleNode::generate_base_tree();

        let mut loaded_fs = HashMap::new();
        let tree = MerkleTree::new(tree_content, root_hash);
        loaded_fs.insert("bob".to_string(), tree);

        Self {
            network_cmd_tx: cmd_tx,
            network_event_rx: event_rx,
            status_message: "Client Initialized. Awaiting network status...".to_string(),
            known_peers: vec!["bob".to_string()],
            connect_address_input: "https://jch.irif.fr:8443".to_string(),
            connect_server_name_input: "jch.irif.fr".to_string(),
            loaded_fs,
            active_peer: None,
            server_status: ServerStatus::Loading,
        }
    }
}

// --- eframe::App Trait Implementation ---

impl eframe::App for P2PClientApp {
    fn update(&mut self, ctx: &Context, _frame: &mut eframe::Frame) {
        // 1. Process incoming Network Events
        // We poll the channel and update the GUI state for every event received.
        while let Ok(event) = self.network_event_rx.try_recv() {
            match event {
                NetworkEvent::PeerConnected(addr) => {
                    todo!();

                    self.status_message = format!("✅ Peer connected: {}", addr);
                    if !self.known_peers.contains(&addr) {
                        self.known_peers.push(addr);
                    }
                }
                NetworkEvent::PeerListUpdated(peers) => {
                    todo!();

                    self.known_peers = peers;
                }
                NetworkEvent::FileTreeReceived(_peer_id, _) => {
                    todo!();

                    // self.loaded_tree_nodes.insert(_peer_id, tree);
                    self.status_message = "🔄 File tree updated successfully.".to_string();
                }
                NetworkEvent::FileTreeRootReceived(peer_id, root_hash) => {
                    todo!();

                    // self.status_message = format!("🔄 Received Merkle Root from {}: {}", peer_id, &root_hash[..8]);
                    //
                    //
                    // self.active_peer_id = Some(peer_id.clone());
                    //
                    //
                    // // Request the content of the root directory immediately
                    // let _ = self.network_cmd_tx.send(NetworkCommand::RequestDirectoryContent(
                    //     peer_id,
                    //     root_hash,
                    // ));
                }
                NetworkEvent::Connected() => {
                    self.server_status = ServerStatus::Connected;
                }
                NetworkEvent::Disconnected() => todo!(),
                NetworkEvent::Error() => todo!(),
                NetworkEvent::DataReceived(_, merkle_node) => todo!(),
            }
        }

        // 2. Menu Bar
        TopBottomPanel::top("top_panel").show(ctx, |ui| {
            egui::MenuBar::new().ui(ui, |ui| {
                ui.menu_button("File", |ui| {
                    if ui.button("Settings").clicked() {
                        //show settings
                    }

                    if ui.button("Quit").clicked() {
                        // Use ViewportCommand to request a close
                        ctx.send_viewport_cmd(ViewportCommand::Close);
                    }
                });

                ui.menu_button("Network", |ui| {
                    ui.horizontal(|ui| {
                        ui.label("Server IP:");
                        ui.text_edit_singleline(&mut self.connect_address_input);
                        ui.text_edit_singleline(&mut self.connect_server_name_input);
                        if ui.button("Connect").clicked() {
                            let addr = self.connect_address_input.clone();
                            let serv_name = self.connect_server_name_input.clone();
                            let _ = self
                                .network_cmd_tx
                                .send(NetworkCommand::ConnectToServer(addr, serv_name));
                            self.server_status = ServerStatus::Loading;
                            ui.close();
                        }
                    });
                });
            });
        });

        TopBottomPanel::bottom("bottom_panel").show(ctx, |ui| {
            ui.horizontal(|ui| {
                match self.server_status {
                    ServerStatus::Loading => {
                        ui.spinner();
                    }
                    ServerStatus::Connected => {
                        ui.label("📡");
                    }
                    ServerStatus::NotConnected => {
                        ui.label("No connection..");
                    }
                }
                ui.add_space(ui.available_width() - 30.0);
                ui.label("30:00");
            });
        });

        SidePanel::right("right_panel")
            .resizable(false)
            .min_width(180.0)
            .show(ctx, |ui| {
                ui.horizontal(|ui| {
                    ui.heading("🌐 Known Peers");
                    ui.add_space(20.0);
                    if ui.button("🔄").clicked() {
                        let res = self.network_cmd_tx.send(NetworkCommand::FetchPeerList(
                            self.connect_address_input.clone(),
                        ));
                        if let Some(error) = res.err() {
                            println!(
                                "[GUI] Error while sending crossbeam message to Network: {}",
                                error.to_string()
                            );
                        }
                    }
                });

                ui.separator();
                ScrollArea::vertical().show(ui, |ui| {
                    if self.known_peers.is_empty() {
                        ui.add_space(10.0);
                        ui.label("No active peers.");
                    } else {
                        for peer in &self.known_peers {
                            let is_active =
                                self.active_peer.as_ref().map_or(false, |id| id == peer); // if peer.id == self.active_peer_id

                            if ui
                                .selectable_label(is_active, format!("{}", peer))
                                .clicked()
                            {
                                // switch to displaying this peer's tree
                                self.active_peer = Some(peer.clone());
                                // Request root content if not loaded
                                if !self
                                    .loaded_fs
                                    .contains_key(self.active_peer.as_ref().unwrap())
                                {
                                    todo!();
                                    // let _ = self.network_cmd_tx.send(NetworkCommand::RequestDirectoryContent(
                                    //     peer.clone(),
                                    //     peer.clone(),
                                    // ));
                                }
                            }
                        }
                    }
                });
            });

        CentralPanel::default().show(ctx, |ui| {
            ui.heading({
                if let Some(peer) = &self.active_peer {
                    format!("📂 {}'s tree", peer)
                } else {
                    "📂 p2p-merkel client".to_string()
                }
            });
            ui.separator();

            if let Some(active_peer) = &self.active_peer {
                if let Some(tree) = self.loaded_fs.get(active_peer) {
                    ScrollArea::vertical().show(ui, |ui| {
                        // Start drawing the tree from the root hash
                        self.draw_file_tree(ui, tree);
                    });
                } else {
                    ui.label(format!("Loading root for peer: {}", active_peer));
                }
            } else {
                ui.label("Connect to a peer to view a file tree.");
            }

            ui.separator();
            ui.add_space(5.0);
            // This is now safe because draw_file_tree only takes an immutable borrow
            // ui.label(format!("Status: {}", self.status_message));
        });

        ctx.request_repaint_after(std::time::Duration::from_millis(10));
    }
}

// --- Helper for Drawing the Recursive File Tree ---

impl P2PClientApp {
    fn draw_file_tree(&self, ui: &mut Ui, tree: &MerkleTree) {
        assert!(self.active_peer.is_some());
        assert!(
            self.loaded_fs
                .get(&self.active_peer.clone().unwrap())
                .is_some()
        );
        let root = tree.root;
        CollapsingHeader::new(format!("📁 root"))
            .default_open(true)
            .enabled(true)
            .show(ui, |ui| {
                self.draw_file_node(ui, root, tree, 0, None);
            });
    }

    fn draw_file_node(
        &self,
        ui: &mut Ui,
        to_draw: NodeHash,
        tree: &MerkleTree,
        depth: usize,
        filename: Option<[u8; 32]>,
    ) {
        if depth >= 32 {
            return;
        }
        if let Some(current) = tree.data.get(&to_draw) {
            let name = {
                if filename.is_some() {
                    filename_to_string(filename.unwrap())
                } else {
                    node_hash_to_hex_string(&to_draw)
                }
            };
            match current {
                MerkleNode::Chunk(node) => {
                    if ui
                        .selectable_label(false, format!("📄 (C) {}...", name))
                        .on_hover_text("Click to request file chunks...")
                        .clicked()
                    {
                        todo!();
                        // if let Some(peer_id) = active_peer_id.clone() {
                        //     let _ = self.network_cmd_tx.send(NetworkCommand::RequestChunk(peer_id, entry_hash.clone()));
                        //     // self.status_message = format!("Requested file chunks for: {}...", &entry_hash[..8]);
                        // }
                    }
                }
                MerkleNode::Directory(node) => {
                    CollapsingHeader::new(format!("📁 (D) {}", name))
                        .default_open(false)
                        .enabled(true)
                        .show(ui, |ui| {
                            for entry in &node.entries {
                                self.draw_file_node(
                                    ui,
                                    entry.content_hash,
                                    tree,
                                    depth + 1,
                                    Some(entry.filename),
                                );
                            }
                        });
                }
                MerkleNode::Big(node) => {
                    CollapsingHeader::new(format!("📄 (B) {}", name))
                        .default_open(false)
                        .enabled(true)
                        .show(ui, |ui| {
                            for child in &node.children_hashes {
                                self.draw_file_node(ui, child.clone(), tree, depth + 1, None);
                            }
                        });
                }
                MerkleNode::BigDirectory(node) => {
                    CollapsingHeader::new(format!("📁 (BD) {}", name))
                        .default_open(false)
                        .enabled(true)
                        .show(ui, |ui| {
                            for child in &node.children_hashes {
                                self.draw_file_node(ui, child.clone(), tree, depth + 1, None);
                            }
                        });
                }
            }
        }
    }
}