use crate::{
    api, app,
    component::text::text,
    query::{self, QueryStatus, read_query, use_query},
};

pub(crate) struct PullRequestDiffView {
    selected_file_path: Option<String>,

    pr_query: query::Entity<api::issues::FetchPullRequest>,
    content_diff_query: Option<query::Entity<api::repo::FetchFileDiff>>,
}

fn new(pr_id: api::issues::Id, cx: &mut gpui::Context<PullRequestDiffView>) -> PullRequestDiffView {
    let mut view = PullRequestDiffView {
        selected_file_path: None,
        pr_query: use_query(api::issues::FetchPullRequest { id: pr_id }, cx),
        content_diff_query: None,
    };
    view.on_create(cx);
    view
}

impl PullRequestDiffView {
    fn on_create(&mut self, cx: &mut gpui::Context<Self>) {
        _ = cx
            .observe(&self.pr_query, |this, _, cx| {
                this.start_content_queries(cx);
            })
            .detach();

        // if pr is already loaded, start content queries
        self.start_content_queries(cx);
    }

    fn start_content_queries(&mut self, cx: &mut gpui::Context<Self>) {
        let Some((old_file_ref, new_file_ref)) = ({
            if let QueryStatus::Loaded(pr) = read_query(&self.pr_query, cx) {
                Some((
                    api::repo::FileRef {
                        repo_slug: pr.base_repo_slug.clone(),
                        path: pr.base_branch_name.clone(),
                        reff: Some(pr.base_ref.clone()),
                    },
                    api::repo::FileRef {
                        repo_slug: pr.head_repo_slug.clone(),
                        path: pr.head_branch_name.clone(),
                        reff: Some(pr.head_ref.clone()),
                    },
                ))
            } else {
                None
            }
        }) else {
            return;
        };

        let content_diff_query = use_query(
            api::repo::FetchFileDiff {
                base: old_file_ref,
                head: new_file_ref,
            },
            cx,
        );

        self.content_diff_query = Some(content_diff_query);
    }
}

impl gpui::Render for PullRequestDiffView {
    fn render(
        &mut self,
        _window: &mut gpui::Window,
        cx: &mut gpui::Context<Self>,
    ) -> impl gpui::IntoElement {
        use gpui::{ParentElement, Styled, div};

        let theme = app::current_theme(cx);

        div()
            .size_full()
            .bg(theme.colors.surface)
            .p_4()
            .child(
                text(
                    "Pull request diff rendering is still under construction. Launch the DiffOps playground with NOVEM_DIFFOPS_PLAYGROUND=1 cargo run.",
                )
                .text_sm()
                .text_color(theme.colors.text_muted),
            )
    }
}