//! `labels <number> [list|add|remove] [labels...]` — manage labels on
//! an issue or PR. Default action: list.

use anyhow::{Result, bail};
use clap::{Args as ClapArgs, Subcommand};
use serde_json::{Value, json};

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

#[derive(ClapArgs)]
pub struct Args {
    /// Issue or PR number.
    number: u64,
    #[command(subcommand)]
    action: Option<Action>,
}

#[derive(Subcommand)]
enum Action {
    /// List labels (default when no action is given).
    List,
    /// Add labels by name.
    Add {
        /// Label names to add.
        labels: Vec<String>,
    },
    /// Remove labels by name.
    Remove {
        /// Label names to remove.
        labels: Vec<String>,
    },
}

pub fn run(client: &Client, args: Args) -> Result<()> {
    let repo = client.repo();
    match args.action.unwrap_or(Action::List) {
        Action::List => {
            let labels = client.get_json(&format!("/repos/{repo}/issues/{}/labels", args.number))?;
            print_label_names(&labels);
        }
        Action::Add { labels } => {
            if labels.is_empty() {
                bail!("hive-forge labels add: pass at least one label name");
            }
            let all = client.get_json(&format!("/repos/{repo}/labels?limit=100"))?;
            let ids = resolve_ids(&all, &labels);
            let resp = client.post_json(
                &format!("/repos/{repo}/issues/{}/labels", args.number),
                &json!({ "labels": ids }),
            )?;
            print_label_names(&resp);
        }
        Action::Remove { labels } => {
            if labels.is_empty() {
                bail!("hive-forge labels remove: pass at least one label name");
            }
            let all = client.get_json(&format!("/repos/{repo}/labels?limit=100"))?;
            for name in &labels {
                if let Some(id) = lookup_id(&all, name) {
                    let _ = client.delete(
                        &format!("/repos/{repo}/issues/{}/labels/{id}", args.number),
                        None,
                    );
                }
            }
            let labels = client.get_json(&format!("/repos/{repo}/issues/{}/labels", args.number))?;
            print_label_names(&labels);
        }
    }
    Ok(())
}

fn resolve_ids(all: &Value, names: &[String]) -> Vec<u64> {
    let Some(arr) = all.as_array() else {
        return Vec::new();
    };
    names
        .iter()
        .filter_map(|n| {
            arr.iter().find_map(|l| {
                let lname = l.get("name").and_then(Value::as_str)?;
                if lname == n {
                    l.get("id").and_then(Value::as_u64)
                } else {
                    None
                }
            })
        })
        .collect()
}

fn lookup_id(all: &Value, name: &str) -> Option<u64> {
    let arr = all.as_array()?;
    arr.iter().find_map(|l| {
        let lname = l.get("name").and_then(Value::as_str)?;
        if lname == name {
            l.get("id").and_then(Value::as_u64)
        } else {
            None
        }
    })
}

fn print_label_names(v: &Value) {
    let names: Vec<&str> = v
        .as_array()
        .map(|a| {
            a.iter()
                .filter_map(|l| l.get("name").and_then(Value::as_str))
                .collect()
        })
        .unwrap_or_default();
    let _ = print_json(&json!(names));
}