//! Diffusion's views (#150, docs/diffusion.md): a repository's Diffusion
//! tab (the consumers that pin it, and what it follows itself), and Admin ›
//! Diffusion across the hub. Each consumer shows green, amber, red, grey
//! or up to date (`diffusion::Colour`).

use super::{filters, lookup, Error, Page, RepoShell, Shell};
use crate::auth::Viewer;
use crate::db::repos::RepoRow;
use crate::diffusion::Consumer;
use crate::Shared;
use askama::Template;
use axum::extract::{Path, State};

#[derive(Template)]
#[template(path = "diffusion.html")]
pub struct DiffusionPage {
    shell: Shell,
    repo: RepoShell,
    used_by: Vec<Consumer>,
    follows: Vec<(RepoRow, Consumer)>,
    /// This repository has no checks of its own: its bumps are amber.
    unverified: bool,
    /// The ripples backdrop's data (docs/backgrounds.md §2): this page's
    /// own repositories and pill tones, JSON safe in a script.
    backdrop: String,
}

/// The ripples' data: the repository, the upstreams it takes from (each in
/// its upstream half's tone) and the consumers it diffuses to (each in its
/// own half's tone), as `{scene, repo, upstreams: [[name, tone]],
/// consumers: [[name, tone]]}`.
fn ripples_json(slug: &str, used_by: &[Consumer], follows: &[(RepoRow, Consumer)]) -> String {
    let tone = |class: &str| class.trim_start_matches("df-").to_string();
    let upstreams: Vec<(String, String)> =
        follows.iter().map(|(up, c)| (format!("{}/{}", up.owner, up.name), tone(c.upstream.class))).collect();
    let consumers: Vec<(String, String)> = used_by.iter().map(|c| (format!("{}/{}", c.owner, c.name), tone(c.downstream.class))).collect();
    serde_json::json!({ "scene": "ripples", "repo": slug, "upstreams": upstreams, "consumers": consumers })
        .to_string()
        .replace('<', "\\u003c")
}

/// `GET /{owner}/{name}/diffusion`.
pub async fn page(
    State(app): State<Shared>,
    viewer: Viewer,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Page<DiffusionPage>, Error> {
    let shell = Shell::new(&app, &format!("/{owner}/{name}/diffusion"), &viewer);
    let (_, row, role) = lookup(&app, &shell, &viewer, &owner, &name).await?;
    let used_by = crate::diffusion::consumers(&app, &row, viewer.account()).await.unwrap_or_default();
    let follows = crate::diffusion::follows(&app, &row, viewer.account()).await;
    let unverified = crate::diffusion::unverified(&app, &row).await;
    let backdrop = ripples_json(&format!("{owner}/{name}"), &used_by, &follows);
    Ok(Page(DiffusionPage { shell, repo: RepoShell::new(&app, &row, "diffusion").with_role(role), used_by, follows, unverified, backdrop }))
}

#[derive(Template)]
#[template(path = "admin_diffusion.html")]
pub struct AdminPage {
    shell: Shell,
    upstreams: Vec<(RepoRow, Vec<Consumer>, bool)>,
}

/// `GET /admin/diffusion`: every upstream on the hub and its consumers.
pub async fn admin(State(app): State<Shared>, viewer: Viewer) -> Result<Page<AdminPage>, Error> {
    let shell = Shell::new(&app, "/admin/diffusion", &viewer);
    if !viewer.is_admin() {
        return Err(Error::not_found(shell));
    }
    let upstreams = crate::diffusion::everything(&app, viewer.account()).await;
    Ok(Page(AdminPage { shell, upstreams }))
}