//! CDK Mint Server

#![warn(missing_docs)]
#![warn(rustdoc::bare_urls)]

use std::collections::{HashMap, HashSet};
use std::path::PathBuf;
use std::str::FromStr;
use std::sync::Arc;

use anyhow::{anyhow, bail, Result};
use axum::Router;
use bip39::Mnemonic;
use cdk::cdk_database::{self, MintDatabase};
use cdk::cdk_lightning;
use cdk::cdk_lightning::MintLightning;
use cdk::mint::{FeeReserve, MeltQuote, Mint};
use cdk::mint_url::MintUrl;
use cdk::nuts::{
    nut04, nut05, ContactInfo, CurrencyUnit, MeltMethodSettings, MeltQuoteState, MintInfo,
    MintMethodSettings, MintVersion, MppMethodSettings, Nuts, PaymentMethod,
};
use cdk::types::{LnKey, QuoteTTL};
use cdk_cln::Cln;
use cdk_fake_wallet::FakeWallet;
use cdk_lnbits::LNbits;
use cdk_lnd::Lnd;
use cdk_phoenixd::Phoenixd;
use cdk_redb::MintRedbDatabase;
use cdk_sqlite::MintSqliteDatabase;
use cdk_strike::Strike;
use clap::Parser;
use cli::CLIArgs;
use config::{DatabaseEngine, LnBackend};
use tokio::sync::{Mutex, Notify};
use tower_http::cors::CorsLayer;
use tracing_subscriber::EnvFilter;
use url::Url;
#[cfg(feature = "swagger")]
use utoipa::OpenApi;

mod cli;
mod config;

const CARGO_PKG_VERSION: Option<&'static str> = option_env!("CARGO_PKG_VERSION");
const DEFAULT_QUOTE_TTL_SECS: u64 = 1800;
const DEFAULT_CACHE_TTL_SECS: u64 = 1800;
const DEFAULT_CACHE_TTI_SECS: u64 = 1800;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let default_filter = "debug";

    let sqlx_filter = "sqlx=warn";
    let hyper_filter = "hyper=warn";

    let env_filter = EnvFilter::new(format!(
        "{},{},{}",
        default_filter, sqlx_filter, hyper_filter
    ));

    tracing_subscriber::fmt().with_env_filter(env_filter).init();

    let args = CLIArgs::parse();

    let work_dir = match args.work_dir {
        Some(w) => w,
        None => work_dir()?,
    };

    // get config file name from args
    let config_file_arg = match args.config {
        Some(c) => c,
        None => work_dir.join("config.toml"),
    };

    let settings = config::Settings::new(&Some(config_file_arg));

    let localstore: Arc<dyn MintDatabase<Err = cdk_database::Error> + Send + Sync> =
        match settings.database.engine {
            DatabaseEngine::Sqlite => {
                let sql_db_path = work_dir.join("cdk-mintd.sqlite");
                let sqlite_db = MintSqliteDatabase::new(&sql_db_path).await?;

                sqlite_db.migrate().await;

                Arc::new(sqlite_db)
            }
            DatabaseEngine::Redb => {
                let redb_path = work_dir.join("cdk-mintd.redb");
                Arc::new(MintRedbDatabase::new(&redb_path)?)
            }
        };

    let mut contact_info: Option<Vec<ContactInfo>> = None;

    if let Some(nostr_contact) = &settings.mint_info.contact_nostr_public_key {
        let nostr_contact = ContactInfo::new("nostr".to_string(), nostr_contact.to_string());

        contact_info = match contact_info {
            Some(mut vec) => {
                vec.push(nostr_contact);
                Some(vec)
            }
            None => Some(vec![nostr_contact]),
        };
    }

    if let Some(email_contact) = &settings.mint_info.contact_email {
        let email_contact = ContactInfo::new("email".to_string(), email_contact.to_string());

        contact_info = match contact_info {
            Some(mut vec) => {
                vec.push(email_contact);
                Some(vec)
            }
            None => Some(vec![email_contact]),
        };
    }

    let mint_version = MintVersion::new(
        "cdk-mintd".to_string(),
        CARGO_PKG_VERSION.unwrap_or("Unknown").to_string(),
    );

    let relative_ln_fee = settings.ln.fee_percent;

    let absolute_ln_fee_reserve = settings.ln.reserve_fee_min;

    let fee_reserve = FeeReserve {
        min_fee_reserve: absolute_ln_fee_reserve,
        percent_fee_reserve: relative_ln_fee,
    };

    let mut ln_backends: HashMap<
        LnKey,
        Arc<dyn MintLightning<Err = cdk_lightning::Error> + Send + Sync>,
    > = HashMap::new();

    let mut supported_units = HashMap::new();
    let input_fee_ppk = settings.info.input_fee_ppk.unwrap_or(0);

    let mint_url: MintUrl = settings.info.url.parse()?;

    let ln_routers: Vec<Router> = match settings.ln.ln_backend {
        LnBackend::Cln => {
            let cln_socket = expand_path(
                settings
                    .cln
                    .expect("Config checked at load that cln is some")
                    .rpc_path
                    .to_str()
                    .ok_or(anyhow!("cln socket not defined"))?,
            )
            .ok_or(anyhow!("cln socket not defined"))?;
            let cln = Arc::new(
                Cln::new(
                    cln_socket,
                    fee_reserve,
                    MintMethodSettings::default(),
                    MeltMethodSettings::default(),
                )
                .await?,
            );

            ln_backends.insert(LnKey::new(CurrencyUnit::Sat, PaymentMethod::Bolt11), cln);
            supported_units.insert(CurrencyUnit::Sat, (input_fee_ppk, 64));
            vec![]
        }
        LnBackend::Strike => {
            let strike_settings = settings.strike.expect("Checked on config load");
            let api_key = strike_settings.api_key;

            let units = strike_settings
                .supported_units
                .unwrap_or(vec![CurrencyUnit::Sat]);

            let mut routers = vec![];

            for unit in units {
                // Channel used for strike web hook
                let (sender, receiver) = tokio::sync::mpsc::channel(8);
                let webhook_endpoint = format!("/webhook/{}/invoice", unit);

                let webhook_url = mint_url.join(&webhook_endpoint)?;

                let strike = Strike::new(
                    api_key.clone(),
                    MintMethodSettings::default(),
                    MeltMethodSettings::default(),
                    unit,
                    Arc::new(Mutex::new(Some(receiver))),
                    webhook_url.to_string(),
                )
                .await?;

                let router = strike
                    .create_invoice_webhook(&webhook_endpoint, sender)
                    .await?;
                routers.push(router);

                let ln_key = LnKey::new(unit, PaymentMethod::Bolt11);

                ln_backends.insert(ln_key, Arc::new(strike));

                supported_units.insert(unit, (input_fee_ppk, 64));
            }

            routers
        }
        LnBackend::LNbits => {
            let lnbits_settings = settings.lnbits.expect("Checked on config load");
            let admin_api_key = lnbits_settings.admin_api_key;
            let invoice_api_key = lnbits_settings.invoice_api_key;

            // Channel used for lnbits web hook
            let (sender, receiver) = tokio::sync::mpsc::channel(8);
            let webhook_endpoint = "/webhook/lnbits/sat/invoice";

            let webhook_url = mint_url.join(webhook_endpoint)?;

            let lnbits = LNbits::new(
                admin_api_key,
                invoice_api_key,
                lnbits_settings.lnbits_api,
                MintMethodSettings::default(),
                MeltMethodSettings::default(),
                fee_reserve,
                Arc::new(Mutex::new(Some(receiver))),
                webhook_url.to_string(),
            )
            .await?;

            let router = lnbits
                .create_invoice_webhook_router(webhook_endpoint, sender)
                .await?;

            let unit = CurrencyUnit::Sat;

            let ln_key = LnKey::new(unit, PaymentMethod::Bolt11);

            ln_backends.insert(ln_key, Arc::new(lnbits));

            supported_units.insert(unit, (input_fee_ppk, 64));
            vec![router]
        }
        LnBackend::Phoenixd => {
            let api_password = settings
                .clone()
                .phoenixd
                .expect("Checked at config load")
                .api_password;

            let api_url = settings
                .clone()
                .phoenixd
                .expect("Checked at config load")
                .api_url;

            if fee_reserve.percent_fee_reserve < 0.04 {
                bail!("Fee reserve is too low needs to be at least 0.02");
            }

            let webhook_endpoint = "/webhook/phoenixd";

            let mint_url = Url::parse(&settings.info.url)?;

            let webhook_url = mint_url.join(webhook_endpoint)?.to_string();

            let (sender, receiver) = tokio::sync::mpsc::channel(8);

            let phoenixd = Phoenixd::new(
                api_password.to_string(),
                api_url.to_string(),
                MintMethodSettings::default(),
                MeltMethodSettings::default(),
                fee_reserve,
                Arc::new(Mutex::new(Some(receiver))),
                webhook_url,
            )?;

            let router = phoenixd
                .create_invoice_webhook(webhook_endpoint, sender)
                .await?;

            supported_units.insert(CurrencyUnit::Sat, (input_fee_ppk, 64));
            ln_backends.insert(
                LnKey {
                    unit: CurrencyUnit::Sat,
                    method: PaymentMethod::Bolt11,
                },
                Arc::new(phoenixd),
            );

            vec![router]
        }
        LnBackend::Lnd => {
            let lnd_settings = settings.lnd.expect("Checked at config load");

            let address = lnd_settings.address;
            let cert_file = lnd_settings.cert_file;
            let macaroon_file = lnd_settings.macaroon_file;

            let lnd = Lnd::new(
                address,
                cert_file,
                macaroon_file,
                fee_reserve,
                MintMethodSettings::default(),
                MeltMethodSettings::default(),
            )
            .await?;

            supported_units.insert(CurrencyUnit::Sat, (input_fee_ppk, 64));
            ln_backends.insert(
                LnKey {
                    unit: CurrencyUnit::Sat,
                    method: PaymentMethod::Bolt11,
                },
                Arc::new(lnd),
            );

            vec![]
        }
        LnBackend::FakeWallet => {
            let units = settings.fake_wallet.unwrap_or_default().supported_units;

            for unit in units {
                let ln_key = LnKey::new(unit, PaymentMethod::Bolt11);

                let wallet = Arc::new(FakeWallet::new(
                    fee_reserve.clone(),
                    MintMethodSettings::default(),
                    MeltMethodSettings::default(),
                    HashMap::default(),
                    HashSet::default(),
                    0,
                ));

                ln_backends.insert(ln_key, wallet);

                supported_units.insert(unit, (input_fee_ppk, 64));
            }

            vec![]
        }
    };

    let (nut04_settings, nut05_settings, mpp_settings): (
        nut04::Settings,
        nut05::Settings,
        Vec<MppMethodSettings>,
    ) = ln_backends.iter().fold(
        (
            nut04::Settings::new(vec![], false),
            nut05::Settings::new(vec![], false),
            Vec::new(),
        ),
        |(mut nut_04, mut nut_05, mut mpp), (key, ln)| {
            let settings = ln.get_settings();

            let m = MppMethodSettings {
                method: key.method,
                unit: key.unit,
                mpp: settings.mpp,
            };

            let n4 = MintMethodSettings {
                method: key.method,
                unit: key.unit,
                min_amount: settings.mint_settings.min_amount,
                max_amount: settings.mint_settings.max_amount,
                description: settings.invoice_description,
            };

            let n5 = MeltMethodSettings {
                method: key.method,
                unit: key.unit,
                min_amount: settings.melt_settings.min_amount,
                max_amount: settings.melt_settings.max_amount,
            };

            nut_04.methods.push(n4);
            nut_05.methods.push(n5);
            mpp.push(m);

            (nut_04, nut_05, mpp)
        },
    );

    let nuts = Nuts::new()
        .nut04(nut04_settings)
        .nut05(nut05_settings)
        .nut07(true)
        .nut08(true)
        .nut09(true)
        .nut10(true)
        .nut11(true)
        .nut12(true)
        .nut14(true)
        .nut15(mpp_settings);

    let mut mint_info = MintInfo::new()
        .name(settings.mint_info.name)
        .version(mint_version)
        .description(settings.mint_info.description)
        .nuts(nuts);

    if let Some(long_description) = &settings.mint_info.description_long {
        mint_info = mint_info.long_description(long_description);
    }

    if let Some(contact_info) = contact_info {
        mint_info = mint_info.contact_info(contact_info);
    }

    if let Some(pubkey) = settings.mint_info.pubkey {
        mint_info = mint_info.pubkey(pubkey);
    }

    if let Some(icon_url) = &settings.mint_info.icon_url {
        mint_info = mint_info.icon_url(icon_url);
    }

    if let Some(motd) = settings.mint_info.motd {
        mint_info = mint_info.motd(motd);
    }

    let mnemonic = Mnemonic::from_str(&settings.info.mnemonic)?;

    let quote_ttl = QuoteTTL::new(10000, 10000);

    let mint = Mint::new(
        &settings.info.url,
        &mnemonic.to_seed_normalized(""),
        mint_info,
        quote_ttl,
        localstore,
        ln_backends.clone(),
        supported_units,
    )
    .await?;

    let mint = Arc::new(mint);

    // Check the status of any mint quotes that are pending
    // In the event that the mint server is down but the ln node is not
    // it is possible that a mint quote was paid but the mint has not been updated
    // this will check and update the mint state of those quotes
    for ln in ln_backends.values() {
        check_pending_mint_quotes(Arc::clone(&mint), Arc::clone(ln)).await?;
    }

    // Checks the status of all pending melt quotes
    // Pending melt quotes where the payment has gone through inputs are burnt
    // Pending melt quotes where the payment has **failed** inputs are reset to unspent
    check_pending_melt_quotes(Arc::clone(&mint), &ln_backends).await?;

    let listen_addr = settings.info.listen_host;
    let listen_port = settings.info.listen_port;
    let _quote_ttl = settings
        .info
        .seconds_quote_is_valid_for
        .unwrap_or(DEFAULT_QUOTE_TTL_SECS);
    let cache_ttl = settings
        .info
        .seconds_to_cache_requests_for
        .unwrap_or(DEFAULT_CACHE_TTL_SECS);
    let cache_tti = settings
        .info
        .seconds_to_extend_cache_by
        .unwrap_or(DEFAULT_CACHE_TTI_SECS);

    let v1_service = cdk_axum::create_mint_router(Arc::clone(&mint), cache_ttl, cache_tti).await?;

    let mut mint_service = Router::new()
        .merge(v1_service)
        .layer(CorsLayer::permissive());

    #[cfg(feature = "swagger")]
    {
        if settings.info.enable_swagger_ui.unwrap_or(false) {
            mint_service = mint_service.merge(
                utoipa_swagger_ui::SwaggerUi::new("/swagger-ui")
                    .url("/api-docs/openapi.json", cdk_axum::ApiDocV1::openapi()),
            );
        }
    }

    for router in ln_routers {
        mint_service = mint_service.merge(router);
    }

    let shutdown = Arc::new(Notify::new());

    tokio::spawn({
        let shutdown = Arc::clone(&shutdown);
        async move { mint.wait_for_paid_invoices(shutdown).await }
    });

    let axum_result = axum::Server::bind(
        &format!("{}:{}", listen_addr, listen_port)
            .as_str()
            .parse()?,
    )
    .serve(mint_service.into_make_service())
    .await;

    shutdown.notify_waiters();

    match axum_result {
        Ok(_) => {
            tracing::info!("Axum server stopped with okay status");
        }
        Err(err) => {
            tracing::warn!("Axum server stopped with error");
            tracing::error!("{}", err);

            bail!("Axum exited with error")
        }
    }

    Ok(())
}

/// Used on mint start up to check status of all pending mint quotes
async fn check_pending_mint_quotes(
    mint: Arc<Mint>,
    ln: Arc<dyn MintLightning<Err = cdk_lightning::Error> + Send + Sync>,
) -> Result<()> {
    let mut pending_quotes = mint.get_pending_mint_quotes().await?;
    tracing::trace!("There are {} pending mint quotes.", pending_quotes.len());
    let mut unpaid_quotes = mint.get_unpaid_mint_quotes().await?;
    tracing::trace!("There are {} unpaid mint quotes.", unpaid_quotes.len());

    unpaid_quotes.append(&mut pending_quotes);

    for quote in unpaid_quotes {
        tracing::trace!("Checking status of mint quote: {}", quote.id);
        let lookup_id = quote.request_lookup_id.as_str();
        match ln.check_incoming_invoice_status(lookup_id).await {
            Ok(state) => {
                if state != quote.state {
                    tracing::trace!("Mint quote status changed: {}", quote.id);
                    mint.localstore
                        .update_mint_quote_state(&quote.id, state)
                        .await?;
                    mint.pubsub_manager.mint_quote_bolt11_status(&quote, state);
                }
            }

            Err(err) => {
                tracing::warn!("Could not check state of pending invoice: {}", lookup_id);
                tracing::error!("{}", err);
            }
        }
    }

    Ok(())
}

async fn check_pending_melt_quotes(
    mint: Arc<Mint>,
    ln_backends: &HashMap<LnKey, Arc<dyn MintLightning<Err = cdk_lightning::Error> + Send + Sync>>,
) -> Result<()> {
    let melt_quotes = mint.localstore.get_melt_quotes().await?;
    let pending_quotes: Vec<MeltQuote> = melt_quotes
        .into_iter()
        .filter(|q| q.state == MeltQuoteState::Pending || q.state == MeltQuoteState::Unknown)
        .collect();

    for pending_quote in pending_quotes {
        let melt_request_ln_key = mint.localstore.get_melt_request(&pending_quote.id).await?;

        let (melt_request, ln_key) = match melt_request_ln_key {
            None => (
                None,
                LnKey {
                    unit: pending_quote.unit,
                    method: PaymentMethod::Bolt11,
                },
            ),
            Some((melt_request, ln_key)) => (Some(melt_request), ln_key),
        };

        let ln_backend = match ln_backends.get(&ln_key) {
            Some(ln_backend) => ln_backend,
            None => {
                tracing::warn!("No backend for ln key: {:?}", ln_key);
                continue;
            }
        };

        let pay_invoice_response = ln_backend
            .check_outgoing_payment(&pending_quote.request_lookup_id)
            .await?;

        match melt_request {
            Some(melt_request) => {
                match pay_invoice_response.status {
                    MeltQuoteState::Paid => {
                        if let Err(err) = mint
                            .process_melt_request(
                                &melt_request,
                                pay_invoice_response.payment_preimage,
                                pay_invoice_response.total_spent,
                            )
                            .await
                        {
                            tracing::error!(
                                "Could not process melt request for pending quote: {}",
                                melt_request.quote
                            );
                            tracing::error!("{}", err);
                        }
                    }
                    MeltQuoteState::Unpaid | MeltQuoteState::Unknown | MeltQuoteState::Failed => {
                        // Payment has not been made we want to unset
                        tracing::info!("Lightning payment for quote {} failed.", pending_quote.id);
                        if let Err(err) = mint.process_unpaid_melt(&melt_request).await {
                            tracing::error!("Could not reset melt quote state: {}", err);
                        }
                    }
                    MeltQuoteState::Pending => {
                        tracing::warn!(
                            "LN payment pending, proofs are stuck as pending for quote: {}",
                            melt_request.quote
                        );
                        // Quote is still pending we do not want to do anything
                        // continue to check next quote
                    }
                }
            }
            None => {
                tracing::warn!(
                    "There is no stored melt request for pending melt quote: {}",
                    pending_quote.id
                );

                mint.localstore
                    .update_melt_quote_state(&pending_quote.id, pay_invoice_response.status)
                    .await?;
            }
        };
    }
    Ok(())
}

fn expand_path(path: &str) -> Option<PathBuf> {
    if path.starts_with('~') {
        if let Some(home_dir) = home::home_dir().as_mut() {
            let remainder = &path[2..];
            home_dir.push(remainder);
            let expanded_path = home_dir;
            Some(expanded_path.clone())
        } else {
            None
        }
    } else {
        Some(PathBuf::from(path))
    }
}

fn work_dir() -> Result<PathBuf> {
    let home_dir = home::home_dir().ok_or(anyhow!("Unknown home dir"))?;

    Ok(home_dir.join(".cdk-mintd"))
}