nostr 0.45.0-alpha.6

use alloc::string::{String, ToString};
use core::str::FromStr;

use super::nip01::Coordinate;
use crate::error::{Error, ErrorKind};
use crate::event::EventId;
use crate::key::PublicKey;
use crate::types::time::Timestamp;
use crate::types::url::RelayUrl;

#[inline]
pub(super) fn missing_tag_kind() -> Error {
    Error::with_static_message(ErrorKind::Missing, "missing tag kind")
}

#[inline]
pub(super) fn invalid_value(value: &'static str) -> Error {
    Error::with_static_message(ErrorKind::Invalid, value)
}

#[inline]
pub(super) fn unknown_tag() -> Error {
    Error::with_static_message(ErrorKind::Malformed, "unknown tag")
}

#[inline]
pub(super) fn missing_value(missing_error: &'static str) -> Error {
    Error::with_static_message(ErrorKind::Missing, missing_error)
}

#[inline]
pub(super) fn invalid_uri() -> Error {
    Error::with_static_message(ErrorKind::Invalid, "invalid URI")
}

#[inline]
#[cfg(any(feature = "nip46", feature = "nip47"))]
pub(super) fn unexpected_result() -> Error {
    Error::with_static_message(ErrorKind::Invalid, "unexpected result")
}

#[inline]
#[cfg(any(feature = "nip46", feature = "nip47"))]
pub(super) fn unsupported_method(method: &str) -> Error {
    Error::new(
        ErrorKind::Unsupported,
        format!("unsupported method: {method}"),
    )
}

#[inline]
pub(super) fn take_and_parse_optional_public_key<I, S>(
    iter: &mut I,
) -> Result<Option<PublicKey>, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    take_and_parse_optional(iter, PublicKey::from_hex)
}

#[inline]
pub(super) fn take_and_parse_optional_coordinate<I, S>(
    iter: &mut I,
) -> Result<Option<Coordinate>, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    take_and_parse_optional(iter, Coordinate::from_kpi_format)
}

#[inline]
pub(super) fn take_and_parse_optional_relay_url<I, S>(
    iter: &mut I,
) -> Result<Option<RelayUrl>, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    take_and_parse_optional(iter, RelayUrl::parse)
}

#[inline]
pub(super) fn take_and_parse_optional_from_str<I, S, T>(iter: &mut I) -> Result<Option<T>, T::Err>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
    T: FromStr,
{
    take_and_parse_optional(iter, T::from_str)
}

/// Take and parse an **optional** value with the provided parser.
///
/// If the value is missing or empty, `None` is returned.
fn take_and_parse_optional<I, S, T, E>(
    iter: &mut I,
    parse: impl FnOnce(&str) -> Result<T, E>,
) -> Result<Option<T>, E>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    match iter.next() {
        Some(value) => {
            let value: &str = value.as_ref();

            if value.is_empty() {
                Ok(None)
            } else {
                // NOTE: we don't use FromStr::from_str here because some implementations, like PublicKey::from_str, support parsing both of hex and also bech32 or URIs, but tags must use just hex.
                parse(value).map(Some)
            }
        }
        None => Ok(None),
    }
}

/// Take an **optional** string
///
/// If the value is empty, None is returned.
pub(super) fn take_optional_string<I, S>(iter: &mut I) -> Option<String>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    iter.next().and_then(|value| {
        let value: &str = value.as_ref();

        if value.is_empty() {
            None
        } else {
            Some(value.to_string())
        }
    })
}

/// Take a string
pub(super) fn take_string<I, S>(iter: &mut I, missing_error: &'static str) -> Result<String, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    let value: S = iter.next().ok_or(missing_value(missing_error))?;
    Ok(value.as_ref().to_string())
}

pub(super) fn take_public_key<I, S>(iter: &mut I) -> Result<PublicKey, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    let public_key: S = iter.next().ok_or(missing_value("public key"))?;
    let public_key: PublicKey = PublicKey::from_hex(public_key.as_ref())?;
    Ok(public_key)
}

pub(super) fn take_coordinate<I, S>(iter: &mut I) -> Result<Coordinate, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    let coordinate: S = iter.next().ok_or(missing_value("coordinate"))?;
    let coordinate: Coordinate = Coordinate::from_kpi_format(coordinate.as_ref())?;
    Ok(coordinate)
}

pub(super) fn take_event_id<I, S>(iter: &mut I) -> Result<EventId, Error>
where
    I: Iterator<Item = S>,
    S: AsRef<str>,
{
    let event_id: S = iter.next().ok_or(missing_value("event ID"))?;
    let event_id: EventId = EventId::from_hex(event_id.as_ref())?;
    Ok(event_id)
}

#[inline]
pub(super) fn take_relay_url<T, S>(iter: &mut T) -> Result<RelayUrl, Error>
where
    T: Iterator<Item = S>,
    S: AsRef<str>,
{
    take_and_parse_from_str(iter, "relay URL")
}

#[inline]
pub(super) fn take_timestamp<T, S>(iter: &mut T) -> Result<Timestamp, Error>
where
    T: Iterator<Item = S>,
    S: AsRef<str>,
{
    take_and_parse_from_str(iter, "timestamp")
}

pub(super) fn take_and_parse_from_str<O, T, S>(
    iter: &mut T,
    missing_error: &'static str,
) -> Result<O, Error>
where
    T: Iterator<Item = S>,
    S: AsRef<str>,
    O: FromStr,
    O::Err: core::fmt::Display,
{
    let value: S = iter.next().ok_or_else(|| missing_value(missing_error))?;
    let value: O = O::from_str(value.as_ref()).map_err(Error::malformed_display)?;
    Ok(value)
}