import objects
import gg
import rand

struct App {
mut:
    gg      &gg.Context       = unsafe { nil }
    ui      &objects.UIParams = unsafe { nil }
    rockets []objects.Rocket
    frames  [][]objects.Rocket
    // i thought about using a fixed fifo queue for the frames but the array
    // seemed to work fine, if you'd like a challenge try implementing it with the queue :)
    draw_flag bool = true
}

fn on_frame(mut app App) {
    if !app.draw_flag {
        return
    }
    app.gg.begin()

    // drawing previous frames
    for mut frame in app.frames {
        for mut rocket in frame {
            if !rocket.exploded {
                rocket.color.a = u8(f32_max(rocket.color.a - 8, 0))
                rocket.draw(mut app.gg)
            }
        }
    }

    // chance of firing new rocket
    if rand.intn(30) or { 0 } == 0 {
        app.rockets << objects.new_rocket()
    }
    // simulating rockets
    app.rockets = app.rockets.filter(!it.dead)

    for mut rocket in app.rockets {
        rocket.tick(mut app.gg)
    }

    // adding frame
    mut frame := app.rockets.clone()

    for mut rocket in frame {
        rocket.particles = []
    }

    app.frames << frame

    // trimming out frames
    if app.frames.len > 30 {
        app.frames.delete(0)
    }

    app.gg.end()
}

fn on_event(e &gg.Event, mut app App) {
    match e.typ {
        .resized, .resumed {
            app.resize()
        }
        .iconified {
            app.draw_flag = false
        }
        .restored {
            app.draw_flag = true
            app.resize()
        }
        else {
            // println("Type ${e.typ}")
        }
    }
}

fn (mut app App) resize() {
    size := gg.window_size()
    // avoid calls when minimized
    if size.width < 2 && size.height < 2 {
        return
    }
    mut s := gg.dpi_scale()

    if s == 0.0 {
        s = 1.0
    }
    app.ui.dpi_scale = s
    app.ui.width = size.width
    app.ui.height = size.height
}

fn main() {
    mut app := &App{}
    app.ui = objects.get_params()
    app.gg = gg.new_context(
        width:        app.ui.width
        height:       app.ui.height
        window_title: 'Fireworks!'
        bg_color:     gg.black
        user_data:    app
        frame_fn:     on_frame
        event_fn:     on_event
    )
    app.gg.run()
}