use crate::{h_flex, theme::ActiveTheme, Icon, IconName, InteractiveElementExt as _, Sizable as _};
use gpui::{
    div, prelude::FluentBuilder as _, px, AnyElement, Hsla, InteractiveElement as _, IntoElement,
    ParentElement, Pixels, RenderOnce, StatefulInteractiveElement as _, Styled, WindowContext,
};

/// TitleBar used to customize the appearance of the title bar.
///
/// We can put some elements inside the title bar.
#[derive(IntoElement)]
pub struct TitleBar {
    children: Vec<AnyElement>,
}

pub const TITLE_BAR_HEIGHT: Pixels = px(35.);

impl TitleBar {
    pub fn new() -> Self {
        Self {
            children: Vec::new(),
        }
    }
}

impl ParentElement for TitleBar {
    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
        self.children.extend(elements);
    }
}

// The Windows control buttons have a fixed width of 35px.
//
// We don't need implementation the click event for the control buttons.
// If user clicked in the bounds, the window event will be triggered.
#[derive(IntoElement, Clone, Copy)]
enum ControlIcon {
    Minimize,
    Restore,
    Maximize,
    Close,
}

impl ControlIcon {
    fn minimize() -> Self {
        Self::Minimize
    }

    fn restore() -> Self {
        Self::Restore
    }

    fn maximize() -> Self {
        Self::Maximize
    }

    fn close() -> Self {
        Self::Close
    }

    fn id(&self) -> &'static str {
        match self {
            Self::Minimize => "minimize",
            Self::Restore => "restore",
            Self::Maximize => "maximize",
            Self::Close => "close",
        }
    }

    fn icon(&self) -> IconName {
        match self {
            Self::Minimize => IconName::WindowMinimize,
            Self::Restore => IconName::WindowRestore,
            Self::Maximize => IconName::WindowMaximize,
            Self::Close => IconName::WindowClose,
        }
    }

    fn is_close(&self) -> bool {
        matches!(self, Self::Close)
    }

    fn fg(&self, cx: &WindowContext) -> Hsla {
        if cx.theme().mode.is_dark() {
            crate::white()
        } else {
            crate::black()
        }
    }

    fn hover_fg(&self, cx: &WindowContext) -> Hsla {
        if self.is_close() || cx.theme().mode.is_dark() {
            crate::white()
        } else {
            crate::black()
        }
    }

    fn hover_bg(&self, cx: &WindowContext) -> Hsla {
        if self.is_close() {
            if cx.theme().mode.is_dark() {
                crate::red_800()
            } else {
                crate::red_600()
            }
        } else if cx.theme().mode.is_dark() {
            crate::stone_700()
        } else {
            crate::stone_200()
        }
    }
}

impl RenderOnce for ControlIcon {
    fn render(self, cx: &mut WindowContext) -> impl IntoElement {
        let fg = self.fg(cx);
        let hover_fg = self.hover_fg(cx);
        let hover_bg = self.hover_bg(cx);
        let icon = self;
        let is_linux = cfg!(target_os = "linux");

        div()
            .id(self.id())
            .flex()
            .cursor_pointer()
            .w(TITLE_BAR_HEIGHT)
            .h_full()
            .justify_center()
            .content_center()
            .items_center()
            .text_color(fg)
            .when(is_linux, |this| {
                this.on_click(move |_, cx| match icon {
                    Self::Minimize => cx.minimize_window(),
                    Self::Restore => cx.zoom_window(),
                    Self::Maximize => cx.zoom_window(),
                    Self::Close => cx.remove_window(),
                })
            })
            .hover(|style| style.bg(hover_bg).text_color(hover_fg))
            .active(|style| style.bg(hover_bg.opacity(0.7)))
            .child(Icon::new(self.icon()).small())
    }
}

#[derive(IntoElement)]
struct WindowControls {}

impl RenderOnce for WindowControls {
    fn render(self, cx: &mut WindowContext) -> impl IntoElement {
        if cfg!(target_os = "macos") {
            return div().id("window-controls");
        }

        h_flex()
            .id("window-controls")
            .items_center()
            .flex_shrink_0()
            .h_full()
            .child(
                h_flex()
                    .justify_center()
                    .content_stretch()
                    .h_full()
                    .child(ControlIcon::minimize())
                    .child(if cx.is_maximized() {
                        ControlIcon::restore()
                    } else {
                        ControlIcon::maximize()
                    }),
            )
            .child(ControlIcon::close())
    }
}

impl RenderOnce for TitleBar {
    fn render(self, cx: &mut WindowContext) -> impl IntoElement {
        let macos_pl = if cfg!(target_os = "macos") {
            Some(px(80.))
        } else {
            None
        };

        h_flex()
            .id("title-bar")
            .flex_shrink_0()
            .items_center()
            .justify_between()
            .pl(px(12.))
            .when(!cx.is_fullscreen(), |this| {
                // Leave space for the macOS window controls.
                this.when_some(macos_pl, |this, pl| this.pl(pl))
            })
            .border_b_1()
            .border_color(cx.theme().title_bar_border)
            .bg(cx.theme().title_bar_background)
            .on_double_click(|_, cx| cx.zoom_window())
            .child(
                h_flex()
                    .h(px(34.))
                    .justify_between()
                    .flex_shrink_0()
                    .flex_1()
                    .children(self.children),
            )
            .child(WindowControls {})
    }
}