//! `repo-labels [pattern]` — list the active repo's full label set
//! (project-wide), not the labels on one issue/PR (that's `labels
//! <number>`). Useful for triage / labelling to discover the valid label
//! names + what each means before applying them.

use anyhow::Result;
use clap::Args as ClapArgs;
use forgejo_api::structs::{IssueListLabelsQuery, Label};

use crate::client::Client;
use crate::verbs::print_json;

/// Page size on the label list endpoint.
const PAGE_SIZE: u32 = 50;

/// Runaway cap on label pagination — same ceiling the raw client used.
const MAX_PAGES: u32 = 10;

#[derive(ClapArgs)]
pub struct Args {
    /// Substring pattern to filter label names (case-sensitive).
    pattern: Option<String>,
}

pub fn run(client: &Client, args: Args) -> Result<()> {
    let (owner, name) = client.owner_repo()?;
    // Repos can carry more than one page of labels; paginate so the list
    // is complete rather than capped at the first page.
    let mut labels: Vec<Label> = Vec::new();
    for page in 1..=MAX_PAGES {
        let (_, batch) = client
            .api()
            .issue_list_labels(owner, name, IssueListLabelsQuery::default())
            .page(page)
            .page_size(PAGE_SIZE)
            .send()?;
        let short = batch.len() < PAGE_SIZE as usize;
        labels.extend(batch);
        if short {
            break;
        }
    }
    let filtered: Vec<&Label> = labels
        .iter()
        .filter(|l| {
            let label_name = l.name.as_deref().unwrap_or_default();
            args.pattern
                .as_deref()
                .is_none_or(|p| label_name.contains(p))
        })
        .collect();

    if client.json_mode() {
        // Full label objects (id, name, color, description) as a JSON array.
        print_json(&serde_json::to_value(&filtered)?)?;
    } else {
        // One label per line: `name`, plus its description (tab-separated)
        // when set, so triage can see what each label means at a glance.
        for l in filtered {
            let label_name = l.name.as_deref().unwrap_or_default();
            let desc = l.description.as_deref().unwrap_or_default();
            if desc.is_empty() {
                println!("{label_name}");
            } else {
                println!("{label_name}\t{desc}");
            }
        }
    }
    Ok(())
}