use cairo;
use ui_model::Color;
use ui::UI;
use shell::{Shell, NvimMode};
use std::sync::{Arc, Mutex};
use gtk::WidgetExt;

use glib;

struct Alpha(f64);

impl Alpha {
    pub fn show(&mut self, step: f64) -> bool {
        self.0 += step;
        if self.0 > 1.0 {
            self.0 = 1.0;
            false
        } else {
            true
        }
    }
    pub fn hide(&mut self, step: f64) -> bool {
        self.0 -= step;
        if self.0 < 0.0 {
            self.0 = 0.0;
            false
        } else {
            true
        }
    }
}

enum AnimPhase {
    Shown,
    Hide,
    Hidden,
    Show,
}

pub struct State {
    alpha: Alpha,
    anim_phase: AnimPhase,
}

impl State {
    pub fn new() -> State {
        State { 
            alpha: Alpha(1.0),
            anim_phase: AnimPhase::Shown,
        }
    }
}

// display, 2 sec -> hiding 1 sec -> not visible 1 sec -> showing 1 sec
pub struct Cursor {
    timer: Option<glib::SourceId>,

    state: Arc<Mutex<State>>,
}

impl Cursor {
    pub fn new() -> Cursor {
        
        Cursor {
            timer: None,
            state: Arc::new(Mutex::new(State::new())),
        }

    }

    pub fn start(&mut self) {
        if self.timer.is_none() {
            let state = self.state.clone();
            self.timer = Some(glib::timeout_add(100, move || {
                let mut mut_state = state.lock().unwrap();
                match mut_state.anim_phase {
                    AnimPhase::Shown => {
                        mut_state.anim_phase = AnimPhase::Hide;
                    }
                    AnimPhase::Hide => {
                        if !mut_state.alpha.hide(0.1) {
                            mut_state.anim_phase = AnimPhase::Hidden;
                        }
                    }
                    AnimPhase::Hidden => {
                        mut_state.anim_phase = AnimPhase::Show;
                    }
                    AnimPhase::Show => {
                        if !mut_state.alpha.show(0.1) {
                            mut_state.anim_phase = AnimPhase::Shown;
                        }
                    }
                }

                SHELL!(&shell = {
                    // FIXME: repaint only changed area
                    shell.drawing_area.queue_draw();
                });
                glib::Continue(true)
            }));
        }
    }

    pub fn draw(&self, ctx: &cairo::Context, shell: &Shell, 
                char_width: f64, line_height: f64, line_y: f64, double_width: bool, bg: &Color) {


        let current_point = ctx.get_current_point();
        let state = self.state.lock().unwrap();
        ctx.set_source_rgba(1.0 - bg.0, 1.0 - bg.1, 1.0 - bg.2, 0.5 * state.alpha.0);

        let cursor_width = if shell.mode == NvimMode::Insert {
            char_width / 5.0
        } else {
            if double_width {
                char_width * 2.0
            } else {
                char_width
            }
        };

        ctx.rectangle(current_point.0, line_y, cursor_width, line_height);
        ctx.fill();
    }
}

impl Drop for Cursor {
    fn drop(&mut self) {
        if let Some(timer_id) = self.timer {
            glib::source_remove(timer_id);
        }
    }
}