use sys;
use std::marker::PhantomData;

use super::{ImStr, ImVec2, ImGuiWindowFlags, Ui};

#[must_use]
pub struct ChildFrame<'ui, 'p> {
    name: &'p ImStr,
    size: ImVec2,
    flags: ImGuiWindowFlags,
    _phantom: PhantomData<&'ui Ui<'ui>>,
}

impl<'ui, 'p> ChildFrame<'ui, 'p> {
    pub fn new<S: Into<ImVec2>>(_: &Ui<'ui>, name: &'p ImStr, size: S) -> ChildFrame<'ui, 'p> {
        ChildFrame {
            name: name,
            size: size.into(),
            flags: ImGuiWindowFlags::empty(),
            _phantom: PhantomData,
        }
    }
    #[inline]
    pub fn movable(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoMove, !value);
        self
    }
    #[inline]
    pub fn show_scrollbar(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoScrollbar, !value);
        self
    }
    #[inline]
    pub fn show_scrollbar_with_mouse(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoScrollWithMouse, !value);
        self
    }
    #[inline]
    pub fn collapsible(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoCollapse, !value);
        self
    }
    #[inline]
    pub fn always_resizable(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::AlwaysAutoResize, value);
        self
    }
    #[inline]
    pub fn show_borders(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::ShowBorders, value);
        self
    }
    #[inline]
    pub fn input_allow(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoInputs, !value);
        self
    }
    #[inline]
    pub fn show_menu(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::MenuBar, value);
        self
    }
    #[inline]
    pub fn scrollbar_horizontal(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::HorizontalScrollbar, value);
        self
    }
    #[inline]
    pub fn focus_on_appearing(mut self, value: bool) -> Self {
        self.flags.set(ImGuiWindowFlags::NoFocusOnAppearing, !value);
        self
    }
    #[inline]
    pub fn bring_to_front_on_focus(mut self, value: bool) -> Self {
        self.flags.set(
            ImGuiWindowFlags::NoBringToFrontOnFocus,
            !value,
        );
        self
    }
    #[inline]
    pub fn always_show_vertical_scroll_bar(mut self, value: bool) -> Self {
        self.flags.set(
            ImGuiWindowFlags::AlwaysVerticalScrollbar,
            value,
        );
        self
    }
    #[inline]
    pub fn always_show_horizontal_scroll_bar(mut self, value: bool) -> Self {
        self.flags.set(
            ImGuiWindowFlags::AlwaysHorizontalScrollbar,
            value,
        );
        self
    }
    #[inline]
    pub fn always_use_window_padding(mut self, value: bool) -> Self {
        self.flags.set(
            ImGuiWindowFlags::AlwaysUseWindowPadding,
            value,
        );
        self
    }
    pub fn build<F: FnOnce()>(self, f: F) {
        // See issue for history.
        // https://github.com/Gekkio/imgui-rs/pull/58
        let show_border = false;

        let render_child_frame =
            unsafe { sys::igBeginChild(self.name.as_ptr(), self.size, show_border, self.flags) };
        if render_child_frame {
            f();
        }
        unsafe { sys::igEndChild() };
    }
}