mod audio;
mod card;
mod cpu;
mod frontpanel;
mod ram;

use std::sync::mpsc::Sender;

use audio::{AudioMessage, AudioThread};
use cpu::{MemCycle, Status, I8080};
use eframe::{
    egui::{self, menu, Button},
    NativeOptions,
};
use egui_modal::Modal;
use frontpanel::Textures;
use rand::RngCore;
use rfd::FileDialog;
use serde::{Deserialize, Serialize};

use crate::frontpanel::{switch::SwitchState, Frontpanel, FrontpanelInteraction, FrontpanelState};

fn main() -> Result<(), eframe::Error> {
    env_logger::init();
    let audio_tx = AudioThread::init();
    eframe::run_native(
        "Altair 8800 Emulator",
        NativeOptions::default(),
        Box::new(|cc| Box::new(AltairEmulator::new(cc, audio_tx))),
    )
}

#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
struct Options {
    fan_enabled: bool,
}

struct AltairEmulator {
    textures: Textures,
    mem: [u8; 65536],
    cpu: I8080,
    running: bool,
    audio_tx: Sender<AudioMessage>,
    options: Options,
    option_window: Option<OptionWindow>,
    fp_state: FrontpanelState,
}

impl AltairEmulator {
    fn new(cc: &eframe::CreationContext<'_>, audio_tx: Sender<AudioMessage>) -> Self {
        let options = if cc.storage.unwrap().get_string("options").is_none() {
            Options { fan_enabled: true }
        } else {
            eframe::get_value(cc.storage.unwrap(), "options").unwrap()
        };
        let mut mem = [0; 65536];
        let cpu = I8080::new();
        rand::thread_rng().fill_bytes(&mut mem);
        mem[0x0] = 0x3a;
        mem[0x1] = 0x10;
        mem[0x2] = 0x00;

        mem[0x3] = 0x47;

        mem[0x4] = 0x3a;
        mem[0x5] = 0x11;
        mem[0x6] = 0x00;

        mem[0x7] = 0x80;

        mem[0x8] = 0x32;
        mem[0x9] = 0x12;
        mem[0xa] = 0x00;

        mem[0xb] = 0x76;

        mem[0x10] = 0x4;
        mem[0x11] = 0x5;
        // 0: 072 020 000
        // 3: 107
        // 4: 072 021 000
        // 7: 200
        // 10: 062 022 000
        // 13: 166
        // 20: 004
        // 21: 005
        Self {
            textures: Textures::new(&cc.egui_ctx),
            mem,
            cpu,
            running: false,
            audio_tx,
            options,
            option_window: None,
            fp_state: FrontpanelState::new(),
        }
    }

    fn update_fp(&mut self) {
        let cycle = self.cpu.get_mem_cycle();
        self.fp_state.set_status(cycle.get_status());
        match cycle {
            MemCycle::Fetch(a) | MemCycle::Read(a) | MemCycle::StackRead(a) => {
                self.fp_state.set_addr(a);
                self.fp_state.set_data(self.mem[a as usize]);
            }
            MemCycle::Write(a, _) | MemCycle::StackWrite(a, _) | MemCycle::Out(a, _) => {
                self.fp_state.set_addr(a);
                self.fp_state.set_data(0xff);
            }
            MemCycle::In(a) => {
                self.fp_state.set_addr(a);
                self.fp_state.set_data(0);
            }
            MemCycle::Inta(_) => todo!(),
            MemCycle::Hlta(_) => {
                self.fp_state.set_addr(0xffff);
                self.fp_state.set_data(0xff);
            }
            MemCycle::IntaHlt(_) => todo!(),
        }
    }

    fn run_cpu_cycle(&mut self) {
        let cycle = self.cpu.get_mem_cycle();
        let data = match cycle {
            MemCycle::Fetch(a) | MemCycle::Read(a) | MemCycle::StackRead(a) => self.mem[a as usize],
            MemCycle::Write(a, d) | MemCycle::StackWrite(a, d) => {
                self.mem[a as usize] = d;
                0
            }
            MemCycle::In(_) => 0,
            MemCycle::Out(_, _) => 0,
            MemCycle::Inta(_) => todo!(),
            MemCycle::Hlta(_) => {
                self.running = false;
                0
            }
            MemCycle::IntaHlt(_) => todo!(),
        };
        self.cpu.finish_m_cycle(data);
        self.update_fp();
    }
}

impl eframe::App for AltairEmulator {
    fn save(&mut self, storage: &mut dyn eframe::Storage) {
        eframe::set_value(storage, "options", &self.options);
    }
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        ctx.set_pixels_per_point(1.0);
        // frame.set_window_size((800.0, 333.0).into());
        let mut disable_fp_sws = self.option_window.is_some();
        egui::TopBottomPanel::top("menu").show(ctx, |ui| {
            menu::bar(ui, |ui| {
                menu::menu_button(ui, "Edit", |ui| {
                    disable_fp_sws = true;
                    if ui
                        .add_enabled(self.option_window.is_none(), Button::new("Options"))
                        .clicked()
                    {
                        self.option_window = Some(OptionWindow::new(ctx, self.options));
                        ui.close_menu();
                    }
                    if ui.button("Load binary file").clicked() {
                        let ihex_exts = ["hex", "mcs", "int", "ihex", "ihe", "ihx"];
                        let file = FileDialog::new()
                            .add_filter(
                                "Binary files",
                                &["bin", "img", "hex", "mcs", "int", "ihex", "ihe", "ihx"],
                            )
                            .add_filter("All files", &["*"])
                            .pick_file();
                        if let Some(file) = file {
                            if file.extension().map_or(false, |ext| {
                                ihex_exts.contains(&ext.to_str().unwrap_or(""))
                            }) {
                                let data = std::fs::read_to_string(file).unwrap();
                                for record in ihex::Reader::new(&data) {
                                    let record = record.unwrap();
                                    match record {
                                        ihex::Record::Data { offset, value } => {
                                            for (i, &byte) in value.iter().enumerate() {
                                                self.mem[offset as usize + i] = byte;
                                            }
                                        }
                                        ihex::Record::StartLinearAddress(_) => todo!(),
                                        _ => unimplemented!(),
                                    };
                                }
                            } else {
                                // Raw binary
                                todo!();
                            }
                        }
                    }
                });
            });
        });
        egui::CentralPanel::default().show(ctx, |ui| {
            let mut fp = Frontpanel::new(&self.textures, &mut self.fp_state);
            ui.add(&mut fp);
            let interaction = fp.interaction();
            if let Some(interaction) = interaction {
                self.audio_tx.send(AudioMessage::PlaySwitchClick).unwrap();
                match interaction {
                    FrontpanelInteraction::ActionSwChanged(sw, state) => {
                        if self.fp_state.power() {
                            match sw {
                                frontpanel::ActionSwitch::RunStop => {
                                    if state == SwitchState::Up {
                                        println!("STOP RUN");
                                        self.running = false;
                                    } else if state == SwitchState::Down {
                                        println!("START RUN");
                                        self.running = true;
                                    }
                                }
                                frontpanel::ActionSwitch::SingleStep => {
                                    if state == SwitchState::Up {
                                        self.run_cpu_cycle();
                                    }
                                }
                                frontpanel::ActionSwitch::Examine => {
                                    if state == SwitchState::Up {
                                        // Assume M1
                                        self.cpu.finish_m_cycle(0xC3); // JMP
                                        self.cpu.finish_m_cycle(self.fp_state.ad_sws() as u8);
                                        self.cpu
                                            .finish_m_cycle((self.fp_state.ad_sws() >> 8) as u8);
                                        self.update_fp();
                                    } else if state == SwitchState::Down {
                                        // Assume M1
                                        self.cpu.finish_m_cycle(0x0); // NOP
                                        self.update_fp();
                                    }
                                }
                                frontpanel::ActionSwitch::Deposit => {
                                    if state == SwitchState::Up {
                                        // Assume M1
                                        self.mem[self.cpu.get_mem_cycle().address() as usize] =
                                            self.fp_state.ad_sws() as u8;
                                        self.update_fp();
                                    } else if state == SwitchState::Down {
                                        // Assume M1
                                        self.cpu.finish_m_cycle(0x0); // NOP
                                        self.mem[self.cpu.get_mem_cycle().address() as usize] =
                                            self.fp_state.ad_sws() as u8;
                                        self.update_fp();
                                    }
                                }
                                frontpanel::ActionSwitch::Reset => {
                                    if state == SwitchState::Up {
                                        self.cpu.reset();
                                        self.update_fp();
                                    }
                                }
                                frontpanel::ActionSwitch::Protect => (),
                                frontpanel::ActionSwitch::Aux1 => (),
                                frontpanel::ActionSwitch::Aux2 => (),
                            }
                        }
                    }
                    FrontpanelInteraction::AdChanged(_) => (),
                    FrontpanelInteraction::PowerChanged(pwr) => {
                        if pwr {
                            self.audio_tx.send(AudioMessage::FanOn).unwrap();
                            self.cpu = I8080::new();
                            self.update_fp();
                        } else {
                            self.audio_tx.send(AudioMessage::FanOff).unwrap();
                            self.running = false;
                            self.fp_state.set_status(Status::empty());
                            self.fp_state.set_addr(0);
                            self.fp_state.set_data(0);
                        }
                    }
                }
            }
            if self.running {
                self.run_cpu_cycle();
            }
        });

        let old_fan_enabled = self.options.fan_enabled;
        if let Some(option_window) = self.option_window.as_mut() {
            if option_window.draw(ctx, &mut self.options) {
                self.option_window = None;
            }
        }
        if (old_fan_enabled != self.options.fan_enabled) && self.fp_state.power() {
            if self.options.fan_enabled {
                self.audio_tx.send(AudioMessage::FanOn).unwrap();
            }  else {
                self.audio_tx.send(AudioMessage::FanOff).unwrap();
            }
        }
        if self.running {
            ctx.request_repaint();
        }
    }
}

struct OptionWindow {
    options: Options,
    category: OptionsCategory,
}

#[derive(PartialEq, Eq)]
enum OptionsCategory {
    General,
    Cards,
}

impl OptionWindow {
    fn new(ctx: &egui::Context, options: Options) -> Self {
        Modal::new(ctx, "options_modal").open();
        Self {
            options,
            category: OptionsCategory::General,
        }
    }
    fn draw(&mut self, ctx: &egui::Context, options: &mut Options) -> bool {
        let modal = Modal::new(ctx, "options_modal");
        modal.show(|ui| {
            modal.title(ui, "Options");
            ui.horizontal(|ui| {
                ui.selectable_value(&mut self.category, OptionsCategory::General, "General");
                ui.selectable_value(&mut self.category, OptionsCategory::Cards, "Cards");
            });
            match self.category {
                OptionsCategory::General => {
                    ui.checkbox(&mut self.options.fan_enabled, "Fan enabled");
                }
                OptionsCategory::Cards => {
                    ui.heading("TODO");
                }
            }
            modal.buttons(ui, |ui| {
                if ui.button("Apply").clicked() {
                    *options = self.options;
                }
                if modal.button(ui, "OK").clicked() {
                    *options = self.options;
                }
                modal.caution_button(ui, "Cancel");
            });
        });
        !modal.is_open()
    }
}