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

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

    pr_query: query::Entity<api::issues::FetchPullRequest>,
    old_content_query: Option<query::Entity<api::repo::FetchFileContent>>,
    new_content_query: Option<query::Entity<api::repo::FetchFileContent>>,
}

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),
        old_content_query: None,
        new_content_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_content_query, new_content_query)) = ({
            if let QueryStatus::Loaded(pr) = read_query(&self.pr_query, cx) {
                Some((
                    api::repo::FetchFileContent {
                        repo_slug: pr.base_repo_slug.clone(),
                        path: pr.base_branch_name.clone(),
                        reff: Some(pr.base_ref.clone()),
                    },
                    api::repo::FetchFileContent {
                        repo_slug: pr.head_repo_slug.clone(),
                        path: pr.head_branch_name.clone(),
                        reff: Some(pr.head_ref.clone()),
                    },
                ))
            } else {
                None
            }
        }) else {
            return;
        };

        let old_content_query = use_query(old_content_query, cx);
        let new_content_query = use_query(new_content_query, cx);

        _ = cx.observe(&old_content_query, |this, _, cx| {}).detach();

        _ = cx.observe(&new_content_query, |this, _, cx| {}).detach();

        self.old_content_query = Some(old_content_query);
        self.new_content_query = Some(new_content_query);
    }
}

impl gpui::Render for PullRequestDiffView {
    fn render(
        &mut self,
        window: &mut gpui::Window,
        cx: &mut gpui::Context<Self>,
    ) -> impl gpui::IntoElement {
        todo!()
    }
}