use gpui::{
    AppContext, InteractiveElement, IntoElement, ParentElement, StatefulInteractiveElement, Styled,
    div, prelude::FluentBuilder,
};

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

pub(crate) struct PullRequestView {
    markdown_viewer: Option<gpui::Entity<MarkdownText>>,

    pull_request_query: Option<query::Entity<api::issues::FetchPullRequest>>,
}

pub fn new(cx: &mut gpui::Context<PullRequestView>) -> PullRequestView {
    PullRequestView {
        markdown_viewer: None,
        pull_request_query: None,
    }
}

impl PullRequestView {
    pub(crate) fn change_displayed_pull_request(
        &mut self,
        id: api::issues::Id,
        cx: &mut gpui::Context<Self>,
    ) {
        let query = use_query(api::issues::FetchPullRequest { id }, cx);

        self.pull_request_query = Some(query.clone());

        _ = cx
            .observe(&query.clone(), move |this, _, cx| {
                this.load_markdown_content(cx);
            })
            .detach();

        // cached query will not trigger observe callback
        // this is required so that content is loaded immediately for cached query
        self.load_markdown_content(cx);

        cx.notify();
    }

    fn load_markdown_content(&mut self, cx: &mut gpui::Context<Self>) {
        let Some(query) = &self.pull_request_query else {
            return;
        };

        let maybe_content = {
            let data = read_query(&query, cx);
            if let QueryStatus::Loaded(pr) = data {
                Some(gpui::SharedString::new(pr.body.as_str()))
            } else {
                None
            }
        };

        self.markdown_viewer = maybe_content.map(|content| cx.new(|cx| markdown::new(content, cx)));

        cx.notify();
    }

    fn pr_content(
        &self,
        pr: &api::issues::DetailedPullRequest,
        cx: &gpui::Context<Self>,
    ) -> gpui::AnyElement {
        let theme = app::current_theme(cx);

        let mut status_pill = div()
            .flex()
            .flex_row()
            .items_center()
            .gap_1()
            .px_2()
            .rounded_full();

        match pr.state {
        | api::issues::PullRequestState::Open => {
            status_pill = status_pill
                .bg(theme.colors.success)
                .child(
                    font_icon(FontIcon::PullRequestArrow)
                        .size_3()
                        .text_color(theme.colors.accent_text),
                )
                .child(text("Open").text_color(theme.colors.accent_text).text_xs());
        }
        | api::issues::PullRequestState::Closed => {
            status_pill = status_pill
                .bg(theme.colors.danger)
                .child(
                    font_icon(FontIcon::PullRequestClosed)
                        .size_3()
                        .text_color(theme.colors.accent_text),
                )
                .child(
                    text("Closed")
                        .text_color(theme.colors.accent_text)
                        .text_xs(),
                );
        }
        | api::issues::PullRequestState::Merged => {
            status_pill = status_pill.bg(theme.colors.accent).child(
                text("Merged")
                    .text_color(theme.colors.accent_text)
                    .text_xs(),
            );
        }
        }

        let author_pill = div()
            .px_2()
            .border_1()
            .border_color(theme.colors.border)
            .rounded_full()
            .bg(theme.colors.surface_elevated)
            .child(text("kennethnym").text_xs());

        let row = div()
            .flex()
            .flex_row()
            .gap_2()
            .child(status_pill)
            .child(author_pill);

        div()
            .size_full()
            .flex()
            .flex_col()
            .overflow_hidden()
            .child(
                div()
                    .w_full()
                    .px_3p5()
                    .py_3()
                    .border_b_1()
                    .border_color(theme.colors.border)
                    .child(text(pr.title.clone()).w_full().text_xl().mb_2())
                    .child(row),
            )
            .child(
                div().flex_1().min_h_0().w_full().child(
                    div()
                        .id("pr-body-content")
                        .size_full()
                        .overflow_y_scroll()
                        .when_some(self.markdown_viewer.as_ref(), |it, viewer| {
                            it.child(div().w_full().p_3p5().child(viewer.clone()))
                        }),
                ),
            )
            .into_any_element()
    }
}

impl gpui::Render for PullRequestView {
    fn render(
        &mut self,
        _window: &mut gpui::Window,
        cx: &mut gpui::Context<Self>,
    ) -> impl gpui::IntoElement {
        div().size_full().child(match &self.pull_request_query {
        | Some(q) => match read_query(q, cx) {
        | QueryStatus::Loaded(pr) => self.pr_content(pr, cx),
        | QueryStatus::Err(e) => div()
            .size_full()
            .child(format!("{:?}", e))
            .into_any_element(),
        | QueryStatus::Loading => div()
            .size_full()
            .child("loading pr content")
            .into_any_element(),
        },
        | None => div().size_full().child("no pr selected").into_any_element(),
        })
    }
}