//! 内容库页的零件：筛选条 / 结果列表 / 详情面板 / 四态（加载 / 空 / 失败 / 无更多）/ 一级切换。
//!
//! 全是既有真组件（`chip` / `list_item` / `buttons` / `empty_state`），页面不自己画状态层。
//!
//! ## 消息口径
//!
//! 本文件的每个控件都直接发 [`crate::pages::Message`]：内容库自己的意图包一层
//! `PageMessage::Content(..)`（[`intent`]），而「取消安装 / 打开日志」用的是**下载页就有的**
//! 那两个变体——因为对用户来说它们是同一件事（同一个 `AppCommand::CancelInstall`）。

use iced::widget::{column, container, row, scrollable};
use iced::{Alignment, Element, Length, Padding};

use unlucky_design::color::Role;
use unlucky_design::icons::IconKind;
use unlucky_design::spacing::Space;
use unlucky_design::typography::TypeRole;

use unlucky_i18n::{Catalog, Key};
use unlucky_presenter::dto::ContentSort;
use unlucky_presenter::router::Route;

use crate::app::components::buttons::{self, Button};
use crate::app::components::feedback::{empty_state, EmptyState};
use crate::app::components::navigation::list_item::{list_item, ListItem};
use crate::app::components::selection::{chip, Chip};
use crate::theme::Ui;

use super::layout::Rails;
use super::model::{Content, Hit, Status};

mod detail;
mod filters;

pub(crate) use detail::detail;
pub(crate) use filters::{filters, labelled};

use super::Message as ContentMessage;
use crate::pages::frame;
use crate::pages::Message as PageMessage;

/// 内容库意图 → 页面消息（唯一的一层包装）。
pub(super) fn intent(message: ContentMessage) -> PageMessage {
    PageMessage::Content(message)
}

/// 结果行与行之间的间距（与下载页同值）。
const ROW_GAP: Space = Space::X1;

/// 一级切换：版本管理 | 内容库（M109 按 B1 裁定：共用同一条导航轨项，页内切换）。
pub(super) fn section_switcher<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    on_content: bool,
) -> Element<'a, PageMessage> {
    let versions = Chip::filter(
        catalog.text(Key::ContentSectionVersions),
        !on_content,
        PageMessage::Navigate(Route::Download),
    );
    let content = Chip::filter(
        catalog.text(Key::ContentSectionContent),
        on_content,
        PageMessage::Navigate(Route::Content),
    );
    row![chip(ui, versions), chip(ui, content)]
        .spacing(ui.space(Space::X2))
        .align_y(Alignment::Center)
        .into()
}

/// 关键词搜索条（输入只改草稿；回车/按钮才发检索指令）。
pub(super) fn search<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    model: &'a Content,
) -> Element<'a, PageMessage> {
    // 输入只改草稿，**提交**才发检索（每敲一个字就打一次网络既没必要也会被限流）。
    // 搜索条自身没有提交回调，所以旁边给一个显式的「搜索」按钮——这也是键盘外的唯一出口。
    let bar = crate::app::components::inputs::search_bar(
        ui,
        crate::app::components::inputs::SearchBar::new(model.draft.as_str())
            .placeholder(catalog.text(Key::ContentSearchPlaceholder)),
        move |text| intent(ContentMessage::QueryChanged(text)),
    );
    let submit = crate::app::components::buttons::text(
        ui,
        crate::app::components::buttons::Button::new(
            catalog.text(Key::ContentSearch),
            intent(ContentMessage::Search),
        )
        .leading(IconKind::Search),
    );
    row![bar, submit]
        .spacing(ui.space(Space::X2))
        .align_y(Alignment::Center)
        .width(Length::Fill)
        .into()
}

/// 结果列表（独立滚动；底部「加载更多」钉在列表之外，见 [`more`]）。
pub(super) fn list<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    model: &'a Content,
    rails: Rails,
) -> Element<'a, PageMessage> {
    let rows = column(
        model
            .hits
            .iter()
            .map(|hit| hit_row(ui, model, hit))
            .collect::<Vec<_>>(),
    )
    .spacing(ui.space(ROW_GAP))
    .padding(Padding::from([0.0, ui.space(Space::X2)]))
    .width(Length::Fill);

    let _ = catalog;
    container(
        scrollable(rows)
            .direction(scrollable::Direction::Vertical(
                scrollable::Scrollbar::new()
                    .width(frame::SCROLLBAR_WIDTH)
                    .scroller_width(frame::SCROLLBAR_WIDTH)
                    .margin(frame::SCROLLBAR_MARGIN),
            ))
            .height(Length::Fill)
            .style(frame::scroll_style(ui)),
    )
    .width(Length::Fixed(rails.list))
    .height(Length::Fill)
    .into()
}

fn hit_row<'a>(ui: &'a Ui, model: &Content, hit: &'a Hit) -> Element<'a, PageMessage> {
    let mut item = ListItem::new(
        hit.title.as_str(),
        intent(ContentMessage::Select(hit.id.clone())),
    )
    .overline(hit.supporting.as_str())
    .supporting(hit.summary.as_str())
    .leading(kind_icon(model.kind));
    if model.selected.as_deref() == Some(hit.id.as_str()) {
        item = item.selected();
    }
    list_item(ui, item)
}

/// 计数头 + 翻页尾（分页而非无限滚动：见 `pages/content.rs` 的模块文档）。
pub(super) fn count_head<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    model: &Content,
) -> Element<'a, PageMessage> {
    let count = if model.total > 0 {
        model.total
    } else {
        u32::try_from(model.hits.len()).unwrap_or(u32::MAX)
    };
    frame::text_role_owned(
        ui,
        TypeRole::LabelMedium,
        false,
        catalog.render(
            Key::ContentCount,
            &[("count", &super::model::thousands(u64::from(count)))],
        ),
        ui.color(Role::OnSurfaceVariant),
    )
}

/// 列表尾部：还有更多 ⇒「加载更多」；没有了 ⇒ 一句「没有更多了」。
pub(super) fn more<'a>(ui: &'a Ui, catalog: Catalog, model: &Content) -> Element<'a, PageMessage> {
    if model.has_more {
        return buttons::text(
            ui,
            Button::new(
                catalog.text(Key::ContentLoadMore),
                intent(ContentMessage::LoadMore),
            )
            .leading(IconKind::ChevronDown),
        );
    }
    frame::text_role(
        ui,
        TypeRole::BodySmall,
        false,
        catalog.text(Key::ContentNoMore),
        ui.color(Role::OnSurfaceVariant),
    )
}

pub(super) fn loading<'a>(ui: &'a Ui, catalog: Catalog) -> Element<'a, PageMessage> {
    centered(
        column![
            frame::text_role_centered(
                ui,
                TypeRole::TitleMedium,
                true,
                catalog.text(Key::ContentLoading),
                ui.color(Role::OnSurface)
            ),
            frame::text_role_centered(
                ui,
                TypeRole::BodySmall,
                false,
                catalog.text(Key::ContentLoadingHint),
                ui.color(Role::OnSurfaceVariant)
            ),
            buttons::text(
                ui,
                Button::new(
                    catalog.text(Key::ContentRetry),
                    intent(ContentMessage::Retry)
                )
            ),
        ]
        .spacing(ui.space(Space::X3))
        .width(Length::Fill)
        .align_x(Alignment::Center),
    )
}

/// 空态（真 `EmptyState`：CTA 是标准 Filled 按钮）。
pub(super) fn empty<'a>(ui: &'a Ui, catalog: Catalog) -> Element<'a, PageMessage> {
    centered(empty_state(
        ui,
        EmptyState::new(
            IconKind::Search,
            catalog.text(Key::ContentEmptyTitle),
            catalog.text(Key::ContentEmptyBody),
        )
        .action(
            catalog.text(Key::ContentRetry),
            intent(ContentMessage::Retry),
        ),
    ))
}

/// 失败态（带原因与重试出口；原因来自 host，不打码不打折）。
pub(super) fn failed<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    reason: &'a str,
) -> Element<'a, PageMessage> {
    centered(
        column![
            row![
                frame::glyph(IconKind::Error, ui.color(Role::Error), frame::ICON_PX),
                frame::text_role(
                    ui,
                    TypeRole::TitleSmall,
                    true,
                    catalog.text(Key::ContentFailedTitle),
                    ui.color(Role::Error)
                ),
            ]
            .spacing(ui.space(Space::X2))
            .align_y(Alignment::Center),
            frame::text_role(
                ui,
                TypeRole::BodySmall,
                false,
                reason,
                ui.color(Role::OnSurfaceVariant)
            ),
            frame::text_role(
                ui,
                TypeRole::BodySmall,
                false,
                catalog.text(Key::ContentFailedBody),
                ui.color(Role::OnSurfaceVariant)
            ),
            buttons::filled(
                ui,
                Button::new(
                    catalog.text(Key::ContentRetry),
                    intent(ContentMessage::Retry)
                )
                .leading(IconKind::Refresh)
            ),
        ]
        .spacing(ui.space(Space::X3))
        .width(Length::Fill)
        .align_x(Alignment::Center),
    )
}

fn centered<'a>(content: impl Into<Element<'a, PageMessage>>) -> Element<'a, PageMessage> {
    container(content)
        .width(Length::Fill)
        .height(Length::Fill)
        .align_x(Alignment::Center)
        .align_y(Alignment::Center)
        .into()
}

/// 内容类型 → 图标（**借用**现有字形：图标集里还没有「整合包/Mod/资源包/光影」四枚专用图标，
/// 已在报告里登记为偏离）。
pub(super) const fn kind_icon(kind: unlucky_presenter::dto::ContentKind) -> IconKind {
    match kind {
        unlucky_presenter::dto::ContentKind::Modpack => IconKind::Folder,
        unlucky_presenter::dto::ContentKind::Mod => IconKind::Instances,
        unlucky_presenter::dto::ContentKind::Resourcepack => IconKind::Download,
        // `Play`/`Stop`/`More` 是**填充**字形，pages 里禁用（tests/no_hardcoded_tokens）：
        // 光影借用 `Expand`（描边的四散光线），语义最近又不撞语汇
        unlucky_presenter::dto::ContentKind::Shader => IconKind::Expand,
    }
}

pub(super) fn sort_label(sort: ContentSort, catalog: Catalog) -> &'static str {
    match sort {
        ContentSort::Relevance => catalog.text(Key::ContentSortRelevance),
        ContentSort::Downloads => catalog.text(Key::ContentSortDownloads),
        ContentSort::Newest => catalog.text(Key::ContentSortNewest),
        ContentSort::Updated => catalog.text(Key::ContentSortUpdated),
    }
}

/// 状态分派（四态各一支；`Ready` 由调用方画列表 + 详情）。
pub(super) fn status_body<'a>(
    ui: &'a Ui,
    catalog: Catalog,
    model: &'a Content,
) -> Option<Element<'a, PageMessage>> {
    match &model.status {
        Status::Loading => Some(loading(ui, catalog)),
        Status::Empty => Some(empty(ui, catalog)),
        Status::Failed(reason) => Some(failed(ui, catalog, reason.as_str())),
        Status::Ready => None,
    }
}