o402 0.1.3

//! TOML-facing types. Field names match the operator file.

use std::net::{Ipv4Addr, SocketAddr};

use indexmap::IndexMap;
use serde::Deserialize;
use url::Url;

use super::secret::Secret;
use super::{
    AcceptConfig, Config, ConfigError, FacilitatorAuth, FacilitatorConfig, LogFormat, ModelConfig,
    ObservabilityConfig, PaymentConfig, PricingConfig, PricingDefault, Scheduler, ServerConfig,
    SettlementConfig, UpstreamConfig, UsagePolicy,
};

/// Root TOML document.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
pub(super) struct RawConfig {
    /// HTTP bind and limits.
    #[serde(default)]
    server: RawServer,
    /// Logs and optional metrics bind.
    #[serde(default)]
    observability: RawObservability,
    /// Payment gate. `enabled` has no default.
    payment: RawPayment,
    /// Upstream LLM providers. At least one is required after validation.
    #[serde(default)]
    upstreams: Vec<RawUpstream>,
    /// Model catalog. Required when payment is on.
    #[serde(default)]
    models: Vec<RawModel>,
    /// Default rates. Required when payment is on.
    #[serde(default)]
    pricing: Option<RawPricing>,
}

/// `[server]` table.
#[derive(Debug, Deserialize)]
#[serde(default, deny_unknown_fields)]
struct RawServer {
    /// Listen address.
    bind: SocketAddr,
    /// Public origin; required when payment is on.
    base_url: Option<Url>,
    /// Drain budget after SIGINT/SIGTERM.
    shutdown_timeout_secs: u64,
    /// Max buffered request body.
    body_limit_bytes: usize,
    /// Non-stream handler timeout.
    request_timeout_secs: u64,
    /// CORS origin list. Empty disables CORS.
    cors: RawCors,
}

impl Default for RawServer {
    fn default() -> Self {
        Self {
            bind: SocketAddr::from((Ipv4Addr::UNSPECIFIED, 8080)),
            base_url: None,
            shutdown_timeout_secs: 30,
            body_limit_bytes: 8_388_608,
            request_timeout_secs: 180,
            cors: RawCors::default(),
        }
    }
}

/// `[server.cors]` table.
#[derive(Debug, Default, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawCors {
    /// Allowed origins. `["*"]` is allowed and logged as a warning later.
    #[serde(default)]
    origins: Vec<String>,
}

/// `[observability]` table.
#[derive(Debug, Deserialize)]
#[serde(default, deny_unknown_fields)]
struct RawObservability {
    /// Fallback when `RUST_LOG` is unset.
    level: String,
    /// `json` or `pretty`.
    format: LogFormat,
    /// Optional Prometheus bind.
    metrics_bind: Option<SocketAddr>,
}

impl Default for RawObservability {
    fn default() -> Self {
        Self {
            level: "info".to_owned(),
            format: LogFormat::Json,
            metrics_bind: None,
        }
    }
}

/// `[payment]` table.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawPayment {
    /// Required. No default: the operator must choose.
    enabled: bool,
    /// Missing-usage policy for `upto`.
    #[serde(default)]
    missing_usage: UsagePolicy,
    /// Client-abort policy for `upto`.
    #[serde(default)]
    abort_usage: UsagePolicy,
    /// `PriceTag` timeout.
    #[serde(default = "default_max_timeout_seconds")]
    max_timeout_seconds: u64,
    /// Remote facilitator. Required when `enabled`.
    #[serde(default)]
    facilitator: Option<RawFacilitator>,
    /// Per-(scheme, stream) schedulers.
    #[serde(default)]
    settlement: RawSettlement,
    /// CAIP-2 pattern → pay-to address.
    #[serde(default)]
    pay_to: IndexMap<String, String>,
    /// Advertised accepts. Required non-empty when `enabled`.
    #[serde(default)]
    accepts: Vec<RawAccept>,
}

const fn default_max_timeout_seconds() -> u64 {
    300
}

/// `[payment.facilitator]` table.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawFacilitator {
    /// Facilitator base URL.
    url: Option<Url>,
    /// HTTP timeout for verify/settle/supported.
    #[serde(default = "default_facilitator_timeout")]
    timeout_secs: u64,
    /// `/supported` cache TTL. `0` means no cache.
    #[serde(default = "default_supported_cache_ttl")]
    supported_cache_ttl_secs: u64,
    /// Path-keyed auth header maps.
    #[serde(default)]
    auth: Option<RawFacilitatorAuth>,
}

const fn default_facilitator_timeout() -> u64 {
    60
}

const fn default_supported_cache_ttl() -> u64 {
    600
}

/// `[payment.facilitator.auth]` table.
#[derive(Debug, Default, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawFacilitatorAuth {
    /// Headers for `POST /verify`.
    #[serde(default)]
    verify: IndexMap<String, Secret<String>>,
    /// Headers for `POST /settle`.
    #[serde(default)]
    settle: IndexMap<String, Secret<String>>,
    /// Headers for `GET /supported`.
    #[serde(default)]
    supported: IndexMap<String, Secret<String>>,
}

/// `[payment.settlement]` table.
#[derive(Debug, Deserialize)]
#[serde(default, deny_unknown_fields)]
struct RawSettlement {
    /// Exact non-stream scheduler.
    exact_non_stream: Scheduler,
    /// Exact stream scheduler.
    exact_stream: Scheduler,
    /// Upto non-stream scheduler.
    upto_non_stream: Scheduler,
    /// Upto stream scheduler. Only `stream-then-settle`.
    upto_stream: Scheduler,
}

impl Default for RawSettlement {
    fn default() -> Self {
        Self {
            exact_non_stream: Scheduler::SequentialWaitSettle,
            exact_stream: Scheduler::Wait2xxThenSpawn,
            upto_non_stream: Scheduler::SequentialWaitSettle,
            upto_stream: Scheduler::StreamThenSettle,
        }
    }
}

/// One `[[payment.accepts]]` row.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawAccept {
    /// `exact` or `upto`.
    scheme: String,
    /// CAIP-2 network.
    network: String,
    /// Named ticker for this namespace xor `asset_address` + `decimals`.
    #[serde(default)]
    asset: Option<String>,
    /// Custom asset address.
    #[serde(default)]
    asset_address: Option<String>,
    /// Custom asset decimals.
    #[serde(default)]
    decimals: Option<u32>,
    /// EVM or Tron exact transfer method.
    #[serde(default)]
    transfer_method: Option<String>,
    /// EIP-712 name for custom EVM assets.
    #[serde(default)]
    eip712_name: Option<String>,
    /// EIP-712 version for custom EVM assets.
    #[serde(default)]
    eip712_version: Option<String>,
}

/// One `[[upstreams]]` row.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawUpstream {
    /// Catalog name referenced by `[[models]]`.
    name: String,
    /// OpenAI-compatible origin.
    base_url: Url,
    /// Injected as `Authorization: Bearer …`. Whole-string `$VAR`.
    api_key: Secret<String>,
    /// Request timeout including streaming generation.
    #[serde(default = "default_upstream_timeout")]
    timeout_secs: u64,
    /// TCP connect timeout.
    #[serde(default = "default_connect_timeout")]
    connect_timeout_secs: u64,
    /// Required for non-HTTPS, non-loopback origins.
    #[serde(default)]
    allow_insecure: bool,
}

const fn default_upstream_timeout() -> u64 {
    120
}

const fn default_connect_timeout() -> u64 {
    10
}

/// One `[[models]]` row.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawModel {
    /// Client-facing model id.
    id: String,
    /// `[[upstreams]]` name.
    upstream: String,
    /// Upstream model id when different from `id`.
    #[serde(default)]
    upstream_model: Option<String>,
    /// OpenAI `owned_by`.
    #[serde(default)]
    owned_by: Option<String>,
    /// `exact` or `upto`. Falls back to `[pricing.default]`.
    #[serde(default)]
    scheme: Option<String>,
    /// Per-million uncached input.
    #[serde(default)]
    input_per_million: Option<String>,
    /// Per-million non-reasoning output.
    #[serde(default)]
    output_per_million: Option<String>,
    /// Per-million cached input.
    #[serde(default)]
    cached_input_per_million: Option<String>,
    /// Per-million reasoning output.
    #[serde(default)]
    reasoning_per_million: Option<String>,
    /// Request floor.
    #[serde(default)]
    request_floor: Option<String>,
    /// Ceiling multiplier.
    #[serde(default)]
    ceiling_multiplier: Option<String>,
    /// Hard ceiling.
    #[serde(default)]
    max_ceiling: Option<String>,
    /// Max input tokens for ceiling.
    #[serde(default)]
    max_input_tokens: Option<u32>,
    /// Default max output tokens for ceiling.
    #[serde(default)]
    default_max_output_tokens: Option<u32>,
    /// Exact per-request price.
    #[serde(default)]
    price: Option<String>,
}

/// `[pricing]` table.
#[derive(Debug, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawPricing {
    /// Defaults inherited by `[[models]]`.
    #[serde(default)]
    default: Option<RawPricingDefault>,
}

/// `[pricing.default]` table.
#[derive(Debug, Default, Deserialize)]
#[serde(deny_unknown_fields)]
struct RawPricingDefault {
    /// Default scheme.
    #[serde(default)]
    scheme: Option<String>,
    /// Default request floor.
    #[serde(default)]
    request_floor: Option<String>,
    /// Default uncached input rate.
    #[serde(default)]
    input_per_million: Option<String>,
    /// Default output rate.
    #[serde(default)]
    output_per_million: Option<String>,
    /// Default cached input rate.
    #[serde(default)]
    cached_input_per_million: Option<String>,
    /// Default reasoning rate.
    #[serde(default)]
    reasoning_per_million: Option<String>,
    /// Default ceiling multiplier.
    #[serde(default)]
    ceiling_multiplier: Option<String>,
    /// Default hard ceiling.
    #[serde(default)]
    max_ceiling: Option<String>,
    /// Default max input tokens.
    #[serde(default)]
    max_input_tokens: Option<u32>,
    /// Default max output tokens.
    #[serde(default)]
    default_max_output_tokens: Option<u32>,
    /// Default exact price.
    #[serde(default)]
    price: Option<String>,
}

impl RawConfig {
    /// Validate and convert to the runtime config.
    pub(super) fn into_config(self) -> Result<Config, ConfigError> {
        validate_cors(&self.server.cors.origins)?;
        if self.observability.level.trim().is_empty() {
            return Err(ConfigError::Validation(
                "observability.level must not be empty".to_owned(),
            ));
        }
        if let Some(metrics_bind) = self.observability.metrics_bind
            && metrics_bind_overlaps(metrics_bind, self.server.bind)
        {
            return Err(ConfigError::Validation(
                "observability.metrics_bind port overlaps server.bind".to_owned(),
            ));
        }

        let payment = self.payment.into_config(self.server.base_url.as_ref())?;
        let upstreams = validate_upstreams(&self.upstreams)?;
        let pricing = validate_pricing(self.pricing, payment.enabled)?;
        let models = validate_models(&self.models, &upstreams, payment.enabled, pricing.as_ref())?;

        Ok(Config {
            server: ServerConfig {
                bind: self.server.bind,
                base_url: self.server.base_url,
                shutdown_timeout_secs: self.server.shutdown_timeout_secs,
                body_limit_bytes: self.server.body_limit_bytes,
                request_timeout_secs: self.server.request_timeout_secs,
                cors_origins: self.server.cors.origins,
            },
            observability: ObservabilityConfig {
                level: self.observability.level,
                format: self.observability.format,
                metrics_bind: self.observability.metrics_bind,
            },
            payment,
            upstreams,
            models,
            pricing,
        })
    }
}

impl RawPayment {
    fn into_config(self, base_url: Option<&Url>) -> Result<PaymentConfig, ConfigError> {
        validate_settlement(&self.settlement)?;
        if self.enabled {
            validate_enabled_payment(&self, base_url)?;
        }

        let facilitator = self
            .facilitator
            .map(|fac| FacilitatorConfig {
                url: fac.url,
                timeout_secs: fac.timeout_secs,
                supported_cache_ttl_secs: fac.supported_cache_ttl_secs,
                auth: fac.auth.map(|auth| FacilitatorAuth {
                    verify: auth.verify,
                    settle: auth.settle,
                    supported: auth.supported,
                }),
            })
            .filter(|fac| self.enabled || fac.url.is_some());

        Ok(PaymentConfig {
            enabled: self.enabled,
            missing_usage: self.missing_usage,
            abort_usage: self.abort_usage,
            max_timeout_seconds: self.max_timeout_seconds,
            facilitator,
            settlement: SettlementConfig {
                exact_non_stream: self.settlement.exact_non_stream,
                exact_stream: self.settlement.exact_stream,
                upto_non_stream: self.settlement.upto_non_stream,
                upto_stream: self.settlement.upto_stream,
            },
            pay_to: self.pay_to,
            accepts: self
                .accepts
                .into_iter()
                .map(|row| AcceptConfig {
                    scheme: row.scheme,
                    network: row.network,
                    asset: row.asset,
                    asset_address: row.asset_address,
                    decimals: row.decimals,
                    transfer_method: row.transfer_method,
                    eip712_name: row.eip712_name,
                    eip712_version: row.eip712_version,
                })
                .collect(),
        })
    }
}

/// Reject mixed `*` and explicit origins.
fn validate_cors(origins: &[String]) -> Result<(), ConfigError> {
    let star = origins.iter().filter(|origin| *origin == "*").count();
    if star > 0 && origins.len() != 1 {
        return Err(ConfigError::Validation(
            "server.cors.origins cannot mix '*' with explicit origins".to_owned(),
        ));
    }
    for origin in origins {
        if origin.is_empty() {
            return Err(ConfigError::Validation(
                "server.cors.origins entries must not be empty".to_owned(),
            ));
        }
    }
    Ok(())
}

fn validate_settlement(settlement: &RawSettlement) -> Result<(), ConfigError> {
    if settlement.exact_non_stream != Scheduler::SequentialWaitSettle {
        return Err(ConfigError::Validation(
            "payment.settlement.exact_non_stream must be sequential-wait-settle".to_owned(),
        ));
    }
    if settlement.exact_stream != Scheduler::Wait2xxThenSpawn {
        return Err(ConfigError::Validation(
            "payment.settlement.exact_stream must be wait-2xx-then-spawn".to_owned(),
        ));
    }
    if settlement.upto_non_stream != Scheduler::SequentialWaitSettle {
        return Err(ConfigError::Validation(
            "payment.settlement.upto_non_stream must be sequential-wait-settle".to_owned(),
        ));
    }
    if settlement.upto_stream != Scheduler::StreamThenSettle {
        return Err(ConfigError::Validation(
            "payment.settlement.upto_stream must be stream-then-settle".to_owned(),
        ));
    }
    Ok(())
}

/// Checks that only apply when `payment.enabled = true`.
fn validate_enabled_payment(
    payment: &RawPayment,
    base_url: Option<&Url>,
) -> Result<(), ConfigError> {
    let Some(base_url) = base_url else {
        return Err(ConfigError::Validation(
            "server.base_url is required when payment.enabled = true".to_owned(),
        ));
    };
    validate_public_base_url(base_url)?;

    let Some(facilitator) = payment.facilitator.as_ref() else {
        return Err(ConfigError::Validation(
            "payment.facilitator.url is required when payment.enabled = true".to_owned(),
        ));
    };
    if facilitator.url.is_none() {
        return Err(ConfigError::Validation(
            "payment.facilitator.url is required when payment.enabled = true".to_owned(),
        ));
    }
    if payment.pay_to.is_empty() {
        return Err(ConfigError::Validation(
            "payment.pay_to is required when payment.enabled = true".to_owned(),
        ));
    }
    if payment.accepts.is_empty() {
        return Err(ConfigError::Validation(
            "payment.accepts must contain at least one entry when payment.enabled = true"
                .to_owned(),
        ));
    }
    for accept in &payment.accepts {
        validate_accept(accept)?;
    }
    Ok(())
}

/// Loopback may be `http`; anything else must be `https`.
fn validate_public_base_url(url: &Url) -> Result<(), ConfigError> {
    match url.scheme() {
        "https" => Ok(()),
        "http" if is_loopback(url) => Ok(()),
        "http" => Err(ConfigError::Validation(
            "server.base_url must be https except on loopback".to_owned(),
        )),
        other => Err(ConfigError::Validation(format!(
            "server.base_url scheme '{other}' is not supported"
        ))),
    }
}

fn validate_accept(accept: &RawAccept) -> Result<(), ConfigError> {
    match accept.scheme.as_str() {
        "exact" => {}
        "upto" => {
            let namespace = accept
                .network
                .split_once(':')
                .map_or("", |(namespace, _)| namespace);
            if namespace != "eip155" {
                return Err(ConfigError::Validation(format!(
                    "scheme = \"upto\" is only supported on eip155 networks (got {})",
                    accept.network
                )));
            }
            if accept.transfer_method.is_some() {
                return Err(ConfigError::Validation(
                    "transfer_method is not valid on upto accepts".to_owned(),
                ));
            }
        }
        other => {
            return Err(ConfigError::Validation(format!(
                "payment.accepts scheme '{other}' is not supported"
            )));
        }
    }
    let named = accept.asset.is_some();
    let custom = accept.asset_address.is_some() || accept.decimals.is_some();
    match (named, custom) {
        (true, false) => Ok(()),
        (false, true) if accept.asset_address.is_some() && accept.decimals.is_some() => Ok(()),
        (false, true) => Err(ConfigError::Validation(
            "custom payment.accepts entries need both asset_address and decimals".to_owned(),
        )),
        (true, true) => Err(ConfigError::Validation(
            "payment.accepts cannot set both asset and asset_address".to_owned(),
        )),
        (false, false) => Err(ConfigError::Validation(
            "payment.accepts needs a named asset or asset_address + decimals".to_owned(),
        )),
    }
}

fn validate_upstreams(rows: &[RawUpstream]) -> Result<Vec<UpstreamConfig>, ConfigError> {
    if rows.is_empty() {
        return Err(ConfigError::Validation(
            "at least one [[upstreams]] entry is required".to_owned(),
        ));
    }
    let mut names = hashbrown::HashSet::new();
    let mut out = Vec::with_capacity(rows.len());
    for row in rows {
        if row.name.is_empty() {
            return Err(ConfigError::Validation(
                "upstreams.name must not be empty".to_owned(),
            ));
        }
        if !names.insert(row.name.as_str()) {
            return Err(ConfigError::Validation(format!(
                "duplicate upstream name '{}'",
                row.name
            )));
        }
        if row.base_url.scheme() != "https" && !is_loopback(&row.base_url) && !row.allow_insecure {
            return Err(ConfigError::Validation(format!(
                "upstream '{}' is not HTTPS; set allow_insecure = true for non-loopback HTTP",
                row.name
            )));
        }
        out.push(UpstreamConfig {
            name: row.name.clone(),
            base_url: row.base_url.clone(),
            api_key: row.api_key.clone(),
            timeout_secs: row.timeout_secs,
            connect_timeout_secs: row.connect_timeout_secs,
            allow_insecure: row.allow_insecure,
        });
    }
    Ok(out)
}

fn validate_models(
    rows: &[RawModel],
    upstreams: &[UpstreamConfig],
    payment_enabled: bool,
    pricing: Option<&PricingConfig>,
) -> Result<Vec<ModelConfig>, ConfigError> {
    let mut ids = hashbrown::HashSet::new();
    let mut out = Vec::with_capacity(rows.len());
    for row in rows {
        if row.id.is_empty() {
            return Err(ConfigError::Validation(
                "models.id must not be empty".to_owned(),
            ));
        }
        if !ids.insert(row.id.as_str()) {
            return Err(ConfigError::Validation(format!(
                "duplicate model id '{}'",
                row.id
            )));
        }
        if !upstreams.iter().any(|up| up.name == row.upstream) {
            return Err(ConfigError::Validation(format!(
                "model '{}' references unknown upstream '{}'",
                row.id, row.upstream
            )));
        }
        if let Some(scheme) = row.scheme.as_deref()
            && scheme != "exact"
            && scheme != "upto"
        {
            return Err(ConfigError::Validation(format!(
                "model '{}' scheme '{scheme}' is not supported",
                row.id
            )));
        }
        if payment_enabled && row.scheme.is_some() {
            validate_paid_model(row, pricing)?;
        }
        out.push(ModelConfig {
            id: row.id.clone(),
            upstream: row.upstream.clone(),
            upstream_model: row.upstream_model.clone(),
            owned_by: row.owned_by.clone(),
            scheme: row.scheme.clone(),
            input_per_million: row.input_per_million.clone(),
            output_per_million: row.output_per_million.clone(),
            cached_input_per_million: row.cached_input_per_million.clone(),
            reasoning_per_million: row.reasoning_per_million.clone(),
            request_floor: row.request_floor.clone(),
            ceiling_multiplier: row.ceiling_multiplier.clone(),
            max_ceiling: row.max_ceiling.clone(),
            max_input_tokens: row.max_input_tokens,
            default_max_output_tokens: row.default_max_output_tokens,
            price: row.price.clone(),
        });
    }
    Ok(out)
}

fn validate_pricing(
    pricing: Option<RawPricing>,
    payment_enabled: bool,
) -> Result<Option<PricingConfig>, ConfigError> {
    let missing = || {
        ConfigError::Validation(
            "pricing.default is required when payment.enabled = true".to_owned(),
        )
    };
    let Some(pricing) = pricing else {
        return if payment_enabled {
            Err(missing())
        } else {
            Ok(None)
        };
    };
    let Some(default) = pricing.default else {
        return if payment_enabled {
            Err(missing())
        } else {
            Ok(Some(PricingConfig { default: None }))
        };
    };
    if payment_enabled {
        if default.price.is_none() {
            return Err(ConfigError::Validation(
                "pricing.default.price is required when payment.enabled = true".to_owned(),
            ));
        }
        if default.input_per_million.is_none()
            || default.output_per_million.is_none()
            || default.max_input_tokens.is_none()
        {
            return Err(ConfigError::Validation(
                "pricing.default needs input_per_million, output_per_million, and max_input_tokens when payment.enabled = true"
                    .to_owned(),
            ));
        }
    }
    Ok(Some(PricingConfig {
        default: Some(PricingDefault {
            scheme: default.scheme,
            request_floor: default.request_floor,
            input_per_million: default.input_per_million,
            output_per_million: default.output_per_million,
            cached_input_per_million: default.cached_input_per_million,
            reasoning_per_million: default.reasoning_per_million,
            ceiling_multiplier: default.ceiling_multiplier,
            max_ceiling: default.max_ceiling,
            max_input_tokens: default.max_input_tokens,
            default_max_output_tokens: default.default_max_output_tokens,
            price: default.price,
        }),
    }))
}

fn validate_paid_model(row: &RawModel, pricing: Option<&PricingConfig>) -> Result<(), ConfigError> {
    let default = pricing.and_then(|pricing| pricing.default.as_ref());
    let scheme = row
        .scheme
        .as_deref()
        .or_else(|| default.and_then(|defaults| defaults.scheme.as_deref()))
        .ok_or_else(|| {
            ConfigError::Validation(format!(
                "model '{}' needs scheme or pricing.default.scheme when payment.enabled = true",
                row.id
            ))
        })?;
    match scheme {
        "upto" => {
            let input = row
                .input_per_million
                .as_deref()
                .or_else(|| default.and_then(|defaults| defaults.input_per_million.as_deref()));
            if input.is_none() {
                return Err(ConfigError::Validation(format!(
                    "model '{}' requires input_per_million when scheme is upto",
                    row.id
                )));
            }
            let max_input = row
                .max_input_tokens
                .or_else(|| default.and_then(|defaults| defaults.max_input_tokens));
            if max_input.is_none() {
                return Err(ConfigError::Validation(format!(
                    "model '{}' requires max_input_tokens when scheme is upto",
                    row.id
                )));
            }
            let output = row
                .output_per_million
                .as_deref()
                .or_else(|| default.and_then(|defaults| defaults.output_per_million.as_deref()));
            if output.is_none() {
                return Err(ConfigError::Validation(format!(
                    "model '{}' requires output_per_million when scheme is upto",
                    row.id
                )));
            }
        }
        "exact" => {
            let price = row
                .price
                .as_deref()
                .or_else(|| default.and_then(|defaults| defaults.price.as_deref()));
            if price.is_none() {
                return Err(ConfigError::Validation(format!(
                    "model '{}' requires price when scheme is exact",
                    row.id
                )));
            }
        }
        other => {
            return Err(ConfigError::Validation(format!(
                "model '{}' scheme '{other}' is not supported",
                row.id
            )));
        }
    }
    Ok(())
}

/// Same port plus equal IPs, or either side unspecified (`0.0.0.0` / `::`).
fn metrics_bind_overlaps(metrics: SocketAddr, server: SocketAddr) -> bool {
    metrics.port() == server.port()
        && (metrics.ip() == server.ip()
            || metrics.ip().is_unspecified()
            || server.ip().is_unspecified())
}

pub(crate) fn is_loopback(url: &Url) -> bool {
    match url.host() {
        Some(url::Host::Ipv4(addr)) => addr.is_loopback(),
        Some(url::Host::Ipv6(addr)) => addr.is_loopback(),
        Some(url::Host::Domain(host)) => host.eq_ignore_ascii_case("localhost"),
        None => false,
    }
}