//! Adds the label signing key (`#atproto_label`) and the labeler endpoint
//! (`#atproto_labeler`) to the account's DID document. Needs the account's main
//! password and a code emailed by the PDS. Run it once the labeler is live at
//! `LABELER_URL`; it exits early if both entries are already in place.
use std::collections::BTreeMap;
use std::io::Write;

use anyhow::{Context, Result, bail};
use cities_labeler::config::Config;
use cities_labeler::login;
use jacquard::AuthorizationToken;
use jacquard::api::com_atproto::identity::sign_plc_operation::SignPlcOperation;
use jacquard::api::com_atproto::identity::submit_plc_operation::SubmitPlcOperation;
use jacquard::client::{Agent, MemoryCredentialSession};
use jacquard::common::to_data;
use jacquard::common::types::crypto::multikey;
use jacquard::prelude::*;
use k256::ecdsa::SigningKey;
use serde::{Deserialize, Serialize};

const PLC_DIRECTORY: &str = "https://plc.directory";

/// The parts of the DID's current PLC state we change; everything else
/// (rotation keys, handle) is left as the PDS has it.
#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
struct PlcData {
    verification_methods: BTreeMap<String, String>,
    services: BTreeMap<String, PlcService>,
}

#[derive(Debug, PartialEq, Deserialize, Serialize)]
struct PlcService {
    #[serde(rename = "type")]
    kind: String,
    endpoint: String,
}

pub async fn run(config: &Config) -> Result<()> {
    let key = SigningKey::from_slice(&hex::decode(&config.signing_key_hex)?)
        .context("SIGNING_KEY_HEX")?;
    let public = key.verifying_key().to_encoded_point(true);
    let label_key = format!("did:key:{}", multikey(0xE7, public.as_bytes()));
    let labeler = PlcService {
        kind: "AtprotoLabeler".into(),
        endpoint: config.labeler_url.clone(),
    };

    // identity changes need the main password; app passwords are refused
    let password = rpassword::prompt_password(format!("main password for {}: ", config.handle))?;
    let (agent, did) = login(&config.handle, &password).await?;

    let url = format!("{PLC_DIRECTORY}/{did}/data");
    let mut plc: PlcData = reqwest::get(&url)
        .await?
        .error_for_status()?
        .json()
        .await
        .with_context(|| format!("reading {url}"))?;
    if plc.verification_methods.get("atproto_label") == Some(&label_key)
        && plc.services.get("atproto_labeler") == Some(&labeler)
    {
        println!("{did} already points at {}", config.labeler_url);
        return Ok(());
    }
    plc.verification_methods
        .insert("atproto_label".into(), label_key.clone());
    plc.services.insert("atproto_labeler".into(), labeler);
    println!(
        "will set on {did}:\n  #atproto_label   {label_key}\n  #atproto_labeler {}",
        config.labeler_url
    );

    request_signature(&agent).await?;
    let token = prompt("code emailed to the account: ")?;
    let signed = agent
        .send(SignPlcOperation {
            token: Some(token.as_str().into()),
            verification_methods: Some(to_data(&plc.verification_methods)?),
            services: Some(to_data(&plc.services)?),
            also_known_as: None,
            rotation_keys: None,
            extra_data: None,
        })
        .await?
        .into_output()?;

    if prompt("submit this PLC operation? [y/N] ")? != "y" {
        bail!("aborted; nothing submitted");
    }
    let response = agent
        .send(SubmitPlcOperation {
            operation: signed.operation,
            extra_data: None,
        })
        .await?;
    // success is an empty body, which into_output() can't decode as JSON
    if !response.status().is_success() {
        response.into_output()?;
        bail!("submitPlcOperation failed");
    }
    println!("submitted; check {PLC_DIRECTORY}/{did}");
    Ok(())
}

/// Asks the PDS to email a PLC operation code. Sent by hand because jacquard
/// serializes this no-input procedure as a `null` JSON body, which the PDS
/// rejects with "A request body was provided when none was expected".
async fn request_signature(agent: &Agent<MemoryCredentialSession>) -> Result<()> {
    let Some(AuthorizationToken::Bearer(token)) = agent.inner().access_token().await else {
        bail!("not logged in");
    };
    let url = format!(
        "{}/xrpc/com.atproto.identity.requestPlcOperationSignature",
        agent.endpoint().await.as_str().trim_end_matches('/')
    );
    let response = reqwest::Client::new()
        .post(&url)
        .bearer_auth(token.as_str())
        .send()
        .await?;
    if !response.status().is_success() {
        bail!(
            "requestPlcOperationSignature failed: {} {}",
            response.status(),
            response.text().await?
        );
    }
    Ok(())
}

fn prompt(label: &str) -> Result<String> {
    print!("{label}");
    std::io::stdout().flush()?;
    let mut line = String::new();
    std::io::stdin().read_line(&mut line)?;
    Ok(line.trim().to_owned())
}