#![cfg_attr(
    all(
        target_os = "windows",
        not(debug_assertions),
    ),
    windows_subsystem = "windows"
)]

use std::collections::{VecDeque};
use std::fs;
use std::time::SystemTime;
use directories::ProjectDirs;
use eframe::{CreationContext, Frame};
use egui::{Color32, Context, RichText, TextEdit, Widget, WidgetText};
use log::info;
use native_dialog::MessageDialog;
use simple_logger::SimpleLogger;
use crate::notes::{Note, NoteMetadata};
use crate::password::{check_password, entropy, generate_new_password};
use crate::saving::Saving;

mod notes;
mod saving;
mod password;

#[derive(PartialEq)]
enum CurrentMode {
    View,
    Compose,
    PasswordInput,
}

struct App {
    notes: Vec<Note>,
    update_notes_next: bool,
    password: Option<String>,
    tested_password: bool,
    mode: CurrentMode,
    saving: Saving,

    password_buffer: String,

    title_buffer: String,
    text_buffer: String,
}

impl App {
    fn new(_cc: &CreationContext<'_>, notes: Vec<Note>, saving: Saving) -> Self {
        Self {
            password: None,
            update_notes_next: false,
            tested_password: false,
            notes,
            mode: CurrentMode::PasswordInput,
            saving,

            password_buffer: String::new(),

            title_buffer: String::new(),
            text_buffer: String::new(),
        }
    }
}

fn main() {
    SimpleLogger::new().init().expect("failed to initialize logger");

    info!("starting the UI");

    let options = eframe::NativeOptions {
        initial_window_size: Some(egui::vec2(640.0, 640.0)),
        ..Default::default()
    };

    let project_directories = ProjectDirs::from("com", "sofiaritz", "notes")
        .unwrap();

    let data_directory = project_directories
        .data_dir();
    info!("data directory: {:?}", data_directory);

    fs::create_dir_all(data_directory).unwrap();
    info!("created all intermediate directories");

    let saving = Saving::new(data_directory);
    let notes = saving.read_notes().unwrap();
    info!("successfully read initial notes");

    eframe::run_native(
        "notes",
        options,
        Box::new(move |cc| Box::new(App::new(cc, notes, saving)))
    ).expect("failed to run native");

    info!("shutdown");
}

impl eframe::App for App {
    fn update(&mut self, ctx: &Context, _frame: &mut Frame) {
        if self.password.is_none() {
            self.mode = CurrentMode::PasswordInput;
        }

        if !self.tested_password && self.password.is_some() {
            if let Some(note) = self.notes.get(0) {
                if let Ok(password) = check_password(self.password.as_ref().unwrap(), note) {
                    self.password = Some(password);
                } else {
                    let _ = MessageDialog::new()
                        .set_title("invalid password")
                        .set_text("failed to verify the password against an existing note. please try again")
                        .show_alert();

                    self.password = None;
                    self.tested_password = false;
                    return;
                }
            } else {
                self.password = Some(generate_new_password(self.password.as_ref().unwrap()))
            }

            self.tested_password = true;
        }

        if self.update_notes_next {
            self.notes = self.saving.read_notes().unwrap();
            self.update_notes_next = false;
            info!("reloaded notes");
        }

        match self.mode {
            CurrentMode::View => {
                let password = self.password.as_ref().unwrap();

                egui::CentralPanel::default().show(ctx, |ui| {
                    ui.heading("notes");
                    ui.horizontal(|ui| {
                        ui.label("the simple note taking app that uses encryption by default");
                        ui.add_space(7.5);
                        if ui.button("want to add one note?").clicked() {
                            self.mode = CurrentMode::Compose;
                        }
                    });
                    ui.separator();

                    egui::ScrollArea::vertical().show(ui, |ui| {
                        for note in &mut self.notes {
                            let render_result = note.render(ui, password, |id| {
                                let _ = &self.saving.delete_note(&id).unwrap();
                                info!("note with id {} was successfully deleted", id);

                                self.update_notes_next = true;
                            });

                            if let Some(new_note) = render_result {
                                *note = new_note;
                            }
                            ui.add_space(10.0);
                        }
                    });
                });
            }
            CurrentMode::Compose => {
                let password = self.password.as_ref().unwrap();

                egui::CentralPanel::default().show(ctx, |ui| {
                    ui.heading("notes");
                    ui.horizontal(|ui| {
                        ui.label("the simple note taking app that uses encryption by default");
                        ui.add_space(7.5);
                        if ui.button("return to view mode?").clicked() {
                            self.title_buffer = String::new();
                            self.text_buffer = String::new();
                            self.mode = CurrentMode::View;
                        }
                    });
                    ui.separator();

                    egui::ScrollArea::vertical().show(ui, |ui| {
                        ui.label("title:");
                        ui.text_edit_singleline(&mut self.title_buffer);

                        ui.label("text:");
                        ui.text_edit_multiline(&mut self.text_buffer);

                        ui.add_space(10.0);
                        if ui.button("add note").clicked() {
                            let note = Note::Decrypted {
                                id: SystemTime::now()
                                    .duration_since(SystemTime::UNIX_EPOCH)
                                    .unwrap()
                                    .as_millis()
                                    .to_string(),
                                title: self.title_buffer.clone(),
                                metadata: NoteMetadata {
                                    date: SystemTime::now(),
                                    arbitrary: None,
                                },
                                text: self.text_buffer.clone(),
                            };

                            self.saving.save_note(note.clone(), password.to_string()).unwrap();

                            let mut vec_deque = VecDeque::from(self.notes.clone());
                            vec_deque.push_front(note);

                            self.notes = Vec::from(vec_deque);

                            self.title_buffer = String::new();
                            self.text_buffer = String::new();
                            self.mode = CurrentMode::View;
                        }
                    });
                });
            }
            CurrentMode::PasswordInput => {
                egui::CentralPanel::default().show(ctx, |ui| {
                    ui.heading("notes");
                    ui.label("the simple note taking app that uses encryption by default");
                    ui.separator();

                    ui.label("you need to put your password to access the notes");
                    ui.label(RichText::new("after starting the app, the password will be tested against the latest note").italics());

                    ui.add_space(10.0);
                    ui.horizontal(|ui| {
                        TextEdit::singleline(&mut self.password_buffer).password(true).ui(ui);
                        let text = if self.password_buffer.len() < 12 {
                            WidgetText::from(format!("length: {}", self.password_buffer.len()))
                                .color(Color32::from_rgb(240, 5, 5))
                        } else {
                            WidgetText::from(format!("length: {}", self.password_buffer.len()))
                                .color(Color32::from_rgb(144, 238, 144))
                        };
                        ui.label(text);

                        let entropy = entropy(&self.password_buffer)
                            .or(Some(0.0))
                            .unwrap();
                        let text = if entropy < 35_f64 {
                            WidgetText::from(format!("entropy: {:.2}", entropy))
                                .color(Color32::from_rgb(240, 5, 5))
                        } else if entropy < 60_f64 {
                            WidgetText::from(format!("entropy: {:.2}", entropy))
                                .color(Color32::from_rgb(220, 88, 42))
                        } else {
                            WidgetText::from(format!("entropy: {:.2}", entropy))
                                .color(Color32::from_rgb(144, 238, 144))
                        };

                        ui.label(text);
                    });
                    ui.add_space(7.5);

                    if ui.button("start app").clicked() {
                        self.password = Some(self.password_buffer.clone());
                        self.password_buffer = String::new();
                        self.mode = CurrentMode::View;
                    }
                });
            }
        }
    }
}