//! 用统一主题绘制宿主管理控件，并同步注册交互目标。
//! 每个控件的图形、角色、启用状态和 action 一起登记，绘制几何与命中几何保持一致。
//!
use super::{
    Axis, Interaction, Role, Target, VisualState, WidgetId,
    theme::{self, Theme},
};
use crate::{
    display_list::{Color, DisplayList, DrawCommand},
    geometry::{Point, Rect},
    text::{self, TextStyle},
};
use std::hash::Hash;

/// 一次按钮绘制的借用描述，包括显示、角色和启用/选中状态。
pub struct Button<'a> {
    pub label: &'a str,
    pub selected: bool,
    pub enabled: bool,
    pub role: Role,
}
impl<'a> Button<'a> {
    /// 构造本类型并初始化其状态；资源建立和默认字段以函数体为准。
    pub fn new(label: &'a str) -> Self {
        Self {
            label,
            selected: false,
            enabled: true,
            role: Role::Button,
        }
    }
    /// 设置当前控件描述的选择、启用或角色信息，供后续绘制和目标登记使用。
    pub fn selected(mut self, value: bool) -> Self {
        self.selected = value;
        self
    }
    /// 设置当前控件描述的选择、启用或角色信息，供后续绘制和目标登记使用。
    pub fn enabled(mut self, value: bool) -> Self {
        self.enabled = value;
        self
    }
    /// 设置当前控件描述的选择、启用或角色信息，供后续绘制和目标登记使用。
    pub fn role(mut self, value: Role) -> Self {
        self.role = value;
        self
    }
}

/// 本帧宿主控件绘制上下文，共同拥有显示列表与交互目标登记入口。
pub struct Ui<A> {
    pub list: DisplayList,
    pub targets: Vec<Target<A>>,
    pub theme: Theme,
    interaction: Interaction,
}
impl<A: Hash> Ui<A> {
    /// 构造本类型并初始化其状态；资源建立和默认字段以函数体为准。
    pub fn new(theme: Theme, interaction: Interaction) -> Self {
        Self {
            list: DisplayList::default(),
            targets: Vec::new(),
            theme,
            interaction,
        }
    }
    /// 使用当前主题绘制控件填充、轮廓或文字原语。
    pub fn fill(&mut self, r: Rect, color: Color) {
        self.list.push(DrawCommand::FillRoundedRect {
            rect: r,
            radius: 0.0,
            color,
        });
    }
    /// 使用当前主题绘制控件填充、轮廓或文字原语。
    fn outline(&mut self, r: Rect, color: Color, width: f32) {
        self.list.push(DrawCommand::StrokeRoundedRect {
            rect: Rect::new(
                r.x + width / 2.0,
                r.y + width / 2.0,
                (r.width - width).max(0.0),
                (r.height - width).max(0.0),
            ),
            radius: 3.0,
            width,
            color,
        });
    }
    /// 使用当前主题绘制控件填充、轮廓或文字原语。
    pub fn label(&mut self, x: f32, y: f32, value: &str, color: Color, code: bool) {
        self.list.push(DrawCommand::Text {
            origin: Point::new(x, y),
            value: value.into(),
            style: if code {
                TextStyle::code()
            } else {
                TextStyle {
                    font_size: 12.0,
                    line_height: 18.0,
                    ..TextStyle::ui(1)
                }
            },
            color,
        });
    }
    /// 把控件身份、几何、角色、启用状态和 action 一起加入本帧交互目标。
    fn register(
        &mut self,
        id: WidgetId,
        rect: Rect,
        role: Role,
        action: Option<A>,
        selected: bool,
        enabled: bool,
    ) -> VisualState {
        let response = self.interaction.visual(id, selected, enabled);
        self.targets.push(Target {
            id,
            rect,
            role,
            enabled,
            action,
        });
        response
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    fn surface(&mut self, rect: Rect, s: VisualState, base: Option<Color>) {
        let color = if !s.enabled {
            base
        } else if s.pressed {
            Some(self.theme.pressed())
        } else if s.hovered {
            Some(self.theme.hover())
        } else if s.selected {
            Some(self.theme.soft())
        } else {
            base
        };
        if let Some(color) = color {
            self.fill(rect, color);
        }
        if s.focused {
            self.outline(rect, self.theme.accent, 1.5);
        }
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn button(&mut self, rect: Rect, action: A, button: Button<'_>) -> VisualState {
        let id = WidgetId::new(&action);
        let s = self.register(
            id,
            rect,
            button.role,
            Some(action),
            button.selected,
            button.enabled,
        );
        self.surface(rect, s, None);
        self.list.push(DrawCommand::PushClip(rect));
        let label = text::fit(
            button.label,
            (rect.width - 16.0).max(0.0),
            TextStyle {
                font_size: 12.0,
                line_height: 18.0,
                ..TextStyle::ui(1)
            },
        );
        self.label(
            rect.x + 8.0,
            rect.y + (rect.height - 18.0) / 2.0,
            &label,
            if s.enabled {
                theme::TEXT
            } else {
                Color::rgb(151, 160, 172)
            },
            false,
        );
        if s.selected && button.role == Role::Tab {
            self.fill(
                Rect::new(rect.x, rect.y + rect.height - 2.0, rect.width, 2.0),
                self.theme.accent,
            );
        }
        self.list.push(DrawCommand::PopClip);
        s
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn text_field(&mut self, rect: Rect, action: A, focused: bool) {
        let s = self.register(
            WidgetId::new(&action),
            rect,
            Role::TextField,
            Some(action),
            false,
            true,
        );
        self.surface(rect, s, Some(theme::BG));
        self.outline(
            rect,
            if focused || s.focused {
                self.theme.accent
            } else if s.hovered {
                theme::MUTED
            } else {
                theme::BORDER
            },
            if focused || s.focused { 1.5 } else { 1.0 },
        );
    }
    /// A terminal prompt shares its surface with output; its caret is the focus cue.
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn inline_input(&mut self, rect: Rect, action: A) {
        self.register(
            WidgetId::new(&action),
            rect,
            Role::TextField,
            Some(action),
            false,
            true,
        );
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn row(&mut self, paint: Rect, hit: Rect, action: A, selected: bool) {
        let s = self.register(
            WidgetId::new(&action),
            hit,
            Role::Row,
            Some(action),
            selected,
            true,
        );
        self.surface(paint, s, None);
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn swatch(&mut self, rect: Rect, action: A, color: Color, selected: bool) {
        let s = self.register(
            WidgetId::new(&action),
            rect,
            Role::Swatch,
            Some(action),
            selected,
            true,
        );
        self.fill(
            rect,
            if s.pressed {
                theme::mix(color, theme::TEXT, 0.2)
            } else {
                color
            },
        );
        if s.hovered || s.focused || selected {
            self.outline(
                Rect::new(
                    rect.x - 3.0,
                    rect.y - 3.0,
                    rect.width + 6.0,
                    rect.height + 6.0,
                ),
                if s.focused {
                    self.theme.accent
                } else {
                    theme::TEXT
                },
                if s.pressed { 3.0 } else { 1.5 },
            );
        }
        if selected {
            self.label(rect.x + 10.0, rect.y + 6.0, "✓", theme::BG, false);
        }
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn splitter(&mut self, rect: Rect, id: WidgetId, axis: Axis) {
        let hit = Rect::new(
            rect.x - 3.0,
            rect.y - 3.0,
            rect.width + 6.0,
            rect.height + 6.0,
        );
        let mut s = self.register(id, hit, Role::Splitter(axis), None, false, true);
        s.pressed |= self.interaction.captured(id);
        let color = if s.pressed || s.hovered {
            self.theme.accent
        } else {
            theme::BORDER
        };
        let line = if s.hovered || s.pressed {
            match axis {
                Axis::Horizontal => Rect::new(rect.x - 1.0, rect.y, 3.0, rect.height),
                Axis::Vertical => Rect::new(rect.x, rect.y - 1.0, rect.width, 3.0),
            }
        } else {
            rect
        };
        self.fill(line, color);
    }
    /// 绘制对应宿主管理控件，并使用同一矩形注册命中/捕获所需的交互信息。
    pub fn scrollbar(&mut self, rect: Rect, id: WidgetId, axis: Axis) {
        let mut s = self.register(id, rect, Role::Scrollbar(axis), None, false, true);
        s.pressed |= self.interaction.captured(id);
        self.fill(
            rect,
            if s.pressed {
                self.theme.accent
            } else if s.hovered {
                theme::mix(theme::MUTED, self.theme.accent, 0.55)
            } else {
                Color::rgb(161, 173, 190)
            },
        );
    }
}