//! Reference implementation of the ZIP-321 standard for payment requests.
//!
//! This module provides data structures, parsing, and rendering functions
//! for interpreting and producing valid ZIP 321 URIs.
//!
//! The specification for ZIP 321 URIs may be found at <https://zips.z.cash/zip-0321>
use core::fmt::Debug;
use std::collections::HashMap;

use nom::{
    character::complete::char, combinator::all_consuming, multi::separated_list0,
    sequence::preceded,
};
use zcash_primitives::{
    consensus,
    memo::{self, MemoBytes},
    transaction::components::Amount,
};

#[cfg(any(test, feature = "test-dependencies"))]
use std::cmp::Ordering;

use crate::address::RecipientAddress;

/// Errors that may be produced in decoding of memos.
#[derive(Debug)]
pub enum MemoError {
    InvalidBase64(base64::DecodeError),
    MemoBytesError(memo::Error),
}

/// Converts a [`MemoBytes`] value to a ZIP 321 compatible base64-encoded string.
///
/// [`MemoBytes`]: zcash_primitives::memo::MemoBytes
pub fn memo_to_base64(memo: &MemoBytes) -> String {
    base64::encode_config(memo.as_slice(), base64::URL_SAFE_NO_PAD)
}

/// Parse a [`MemoBytes`] value from a ZIP 321 compatible base64-encoded string.
///
/// [`MemoBytes`]: zcash_primitives::memo::MemoBytes
pub fn memo_from_base64(s: &str) -> Result<MemoBytes, MemoError> {
    base64::decode_config(s, base64::URL_SAFE_NO_PAD)
        .map_err(MemoError::InvalidBase64)
        .and_then(|b| MemoBytes::from_bytes(&b).map_err(MemoError::MemoBytesError))
}

/// A single payment being requested.
#[derive(Debug, PartialEq)]
pub struct Payment {
    /// The payment address to which the payment should be sent.
    pub recipient_address: RecipientAddress,
    /// The amount of the payment that is being requested.
    pub amount: Amount,
    /// A memo that, if included, must be provided with the payment.
    /// If a memo is present and [`recipient_address`] is not a shielded
    /// address, the wallet should report an error.
    ///
    /// [`recipient_address`]: #structfield.recipient_address
    pub memo: Option<MemoBytes>,
    /// A human-readable label for this payment within the larger structure
    /// of the transaction request.
    pub label: Option<String>,
    /// A human-readable message to be displayed to the user describing the
    /// purpose of this payment.
    pub message: Option<String>,
    /// A list of other arbitrary key/value pairs associated with this payment.
    pub other_params: Vec<(String, String)>,
}

impl Payment {
    /// A utility for use in tests to help check round-trip serialization properties.
    #[cfg(any(test, feature = "test-dependencies"))]
    pub(in crate::zip321) fn normalize(&mut self) {
        self.other_params.sort();
    }

    /// Returns a function which compares two normalized payments, with addresses sorted by their
    /// string representation given the specified network. This does not perform normalization
    /// internally, so payments must be normalized prior to being passed to the comparison function
    /// returned from this method.
    #[cfg(any(test, feature = "test-dependencies"))]
    pub(in crate::zip321) fn compare_normalized<P: consensus::Parameters>(
        params: &P,
    ) -> impl Fn(&Payment, &Payment) -> Ordering + '_ {
        move |a: &Payment, b: &Payment| {
            let a_addr = a.recipient_address.encode(params);
            let b_addr = b.recipient_address.encode(params);

            a_addr
                .cmp(&b_addr)
                .then(a.amount.cmp(&b.amount))
                .then(a.memo.cmp(&b.memo))
                .then(a.label.cmp(&b.label))
                .then(a.message.cmp(&b.message))
                .then(a.other_params.cmp(&b.other_params))
        }
    }
}

/// A ZIP321 transaction request.
///
/// A ZIP 321 request may include one or more such requests for payment.
/// When constructing a transaction in response to such a request,
/// a separate output should be added to the transaction for each
/// payment value in the request.
#[derive(Debug, PartialEq)]
pub struct TransactionRequest {
    payments: Vec<Payment>,
}

impl TransactionRequest {
    /// A utility for use in tests to help check round-trip serialization properties.
    #[cfg(any(test, feature = "test-dependencies"))]
    pub(in crate::zip321) fn normalize<P: consensus::Parameters>(&mut self, params: &P) {
        for p in &mut self.payments {
            p.normalize();
        }

        self.payments.sort_by(Payment::compare_normalized(params));
    }

    /// A utility for use in tests to help check round-trip serialization properties.
    /// by comparing a two transaction requests for equality after normalization.
    #[cfg(all(test, feature = "test-dependencies"))]
    pub(in crate::zip321) fn normalize_and_eq<P: consensus::Parameters>(
        params: &P,
        a: &mut TransactionRequest,
        b: &mut TransactionRequest,
    ) -> bool {
        a.normalize(params);
        b.normalize(params);

        a == b
    }

    /// Convert this request to a URI string.
    ///
    /// Returns None if the payment request is empty.
    pub fn to_uri<P: consensus::Parameters>(&self, params: &P) -> Option<String> {
        fn payment_params(
            payment: &Payment,
            payment_index: Option<usize>,
        ) -> impl IntoIterator<Item = String> + '_ {
            std::iter::empty()
                .chain(render::amount_param(payment.amount, payment_index))
                .chain(
                    payment
                        .memo
                        .as_ref()
                        .map(|m| render::memo_param(&m, payment_index)),
                )
                .chain(
                    payment
                        .label
                        .as_ref()
                        .map(|m| render::str_param("label", &m, payment_index)),
                )
                .chain(
                    payment
                        .message
                        .as_ref()
                        .map(|m| render::str_param("message", &m, payment_index)),
                )
                .chain(
                    payment
                        .other_params
                        .iter()
                        .map(move |(name, value)| render::str_param(&name, &value, payment_index)),
                )
        }

        match &self.payments[..] {
            [] => None,
            [payment] => {
                let query_params = payment_params(&payment, None)
                    .into_iter()
                    .collect::<Vec<String>>();

                Some(format!(
                    "zcash:{}?{}",
                    payment.recipient_address.encode(params),
                    query_params.join("&")
                ))
            }
            _ => {
                let query_params = self
                    .payments
                    .iter()
                    .enumerate()
                    .flat_map(|(i, payment)| {
                        let primary_address = payment.recipient_address.clone();
                        std::iter::empty()
                            .chain(Some(render::addr_param(params, &primary_address, Some(i))))
                            .chain(payment_params(&payment, Some(i)))
                    })
                    .collect::<Vec<String>>();

                Some(format!("zcash:?{}", query_params.join("&")))
            }
        }
    }

    /// Parse the provided URI to a payment request value.
    pub fn from_uri<P: consensus::Parameters>(params: &P, uri: &str) -> Result<Self, String> {
        // Parse the leading zcash:<address>
        let (rest, primary_addr_param) =
            parse::lead_addr(params)(uri).map_err(|e| e.to_string())?;

        // Parse the remaining parameters as an undifferentiated list
        let (_, xs) = all_consuming(preceded(
            char('?'),
            separated_list0(char('&'), parse::zcashparam(params)),
        ))(rest)
        .map_err(|e| e.to_string())?;

        // Construct sets of payment parameters, keyed by the payment index.
        let mut params_by_index: HashMap<usize, Vec<parse::Param>> = HashMap::new();

        // Add the primary address, if any, to the index.
        if let Some(p) = primary_addr_param {
            params_by_index.insert(p.payment_index, vec![p.param]);
        }

        // Group the remaining parameters by payment index
        for p in xs {
            match params_by_index.get_mut(&p.payment_index) {
                None => {
                    params_by_index.insert(p.payment_index, vec![p.param]);
                }

                Some(current) => {
                    if parse::has_duplicate_param(&current, &p.param) {
                        return Err(format!(
                            "Found duplicate parameter {:?} at index {}",
                            p.param, p.payment_index
                        ));
                    } else {
                        current.push(p.param);
                    }
                }
            }
        }

        // Build the actual payment values from the index.
        params_by_index
            .into_iter()
            .map(|(i, params)| parse::to_payment(params, i))
            .collect::<Result<Vec<_>, _>>()
            .map(|payments| TransactionRequest { payments })
    }
}

mod render {
    use percent_encoding::{utf8_percent_encode, AsciiSet, CONTROLS};

    use zcash_primitives::{
        consensus, transaction::components::amount::COIN, transaction::components::Amount,
    };

    use super::{memo_to_base64, MemoBytes, RecipientAddress};

    /// The set of ASCII characters that must be percent-encoded according
    /// to the definition of ZIP 321. This is the complement of the subset of
    /// ASCII characters defined by `qchar`
    ///
    //      unreserved      = ALPHA / DIGIT / "-" / "." / "_" / "~"
    //      allowed-delims  = "!" / "$" / "'" / "(" / ")" / "*" / "+" / "," / ";"
    //      qchar           = unreserved / pct-encoded / allowed-delims / ":" / "@"
    pub const QCHAR_ENCODE: &AsciiSet = &CONTROLS
        .add(b' ')
        .add(b'"')
        .add(b'#')
        .add(b'%')
        .add(b'&')
        .add(b'/')
        .add(b'<')
        .add(b'=')
        .add(b'>')
        .add(b'?')
        .add(b'[')
        .add(b'\\')
        .add(b']')
        .add(b'^')
        .add(b'`')
        .add(b'{')
        .add(b'|')
        .add(b'}');

    /// Converts a parameter index value to the `String` representation
    /// that must be appended to a parameter name when constructing a ZIP 321 URI.
    pub fn param_index(idx: Option<usize>) -> String {
        match idx {
            Some(i) if i > 0 => format!(".{}", i),
            _otherwise => "".to_string(),
        }
    }

    /// Constructs an "address" key/value pair containing the encoded recipient address
    /// at the specified parameter index.
    pub fn addr_param<P: consensus::Parameters>(
        params: &P,
        addr: &RecipientAddress,
        idx: Option<usize>,
    ) -> String {
        format!("address{}={}", param_index(idx), addr.encode(params))
    }

    /// Converts an [`Amount`] value to a correctly formatted decimal ZEC
    /// value for inclusion in a ZIP 321 URI.
    pub fn amount_str(amount: Amount) -> Option<String> {
        if amount.is_positive() {
            let coins = i64::from(amount) / COIN;
            let zats = i64::from(amount) % COIN;
            Some(if zats == 0 {
                format!("{}", coins)
            } else {
                format!("{}.{:0>8}", coins, zats)
                    .trim_end_matches('0')
                    .to_string()
            })
        } else {
            None
        }
    }

    /// Constructs an "amount" key/value pair containing the encoded ZEC amount
    /// at the specified parameter index.
    pub fn amount_param(amount: Amount, idx: Option<usize>) -> Option<String> {
        amount_str(amount).map(|s| format!("amount{}={}", param_index(idx), s))
    }

    /// Constructs a "memo" key/value pair containing the base64URI-encoded memo
    /// at the specified parameter index.
    pub fn memo_param(value: &MemoBytes, idx: Option<usize>) -> String {
        format!("{}{}={}", "memo", param_index(idx), memo_to_base64(value))
    }

    /// Utility function for an arbitrary string key/value pair for inclusion in
    /// a ZIP 321 URI at the specified parameter index.
    pub fn str_param(label: &str, value: &str, idx: Option<usize>) -> String {
        format!(
            "{}{}={}",
            label,
            param_index(idx),
            utf8_percent_encode(value, QCHAR_ENCODE)
        )
    }
}

mod parse {
    use core::fmt::Debug;

    use nom::{
        bytes::complete::{tag, take_until},
        character::complete::{alpha1, char, digit0, digit1, one_of},
        combinator::{map_opt, map_res, opt, recognize},
        sequence::{preceded, separated_pair, tuple},
        AsChar, IResult, InputTakeAtPosition,
    };
    use percent_encoding::percent_decode;
    use zcash_primitives::{
        consensus, transaction::components::amount::COIN, transaction::components::Amount,
    };

    use crate::address::RecipientAddress;

    use super::{memo_from_base64, MemoBytes, Payment};

    /// A data type that defines the possible parameter types which may occur within a
    /// ZIP 321 URI.
    #[derive(Debug, PartialEq)]
    pub enum Param {
        Addr(RecipientAddress),
        Amount(Amount),
        Memo(MemoBytes),
        Label(String),
        Message(String),
        Other(String, String),
    }

    /// A [`Param`] value with its associated index.
    #[derive(Debug)]
    pub struct IndexedParam {
        pub param: Param,
        pub payment_index: usize,
    }

    /// Utility function for determining parameter uniqueness.
    ///
    /// Utility function for determining whether a newly parsed param is a duplicate
    /// of a previous parameter.
    pub fn has_duplicate_param(v: &[Param], p: &Param) -> bool {
        for p0 in v {
            match (p0, p) {
                (Param::Addr(_), Param::Addr(_)) => return true,
                (Param::Amount(_), Param::Amount(_)) => return true,
                (Param::Memo(_), Param::Memo(_)) => return true,
                (Param::Label(_), Param::Label(_)) => return true,
                (Param::Message(_), Param::Message(_)) => return true,
                (Param::Other(n, _), Param::Other(n0, _)) if (n == n0) => return true,
                _otherwise => continue,
            }
        }

        false
    }

    /// Converts an vector of [`Param`] values to a [`Payment`].
    ///
    /// This function performs checks to ensure that the resulting [`Payment`] is structurally
    /// valid; for example, a request for memo contents may not be associated with a
    /// transparent payment address.
    pub fn to_payment(vs: Vec<Param>, i: usize) -> Result<Payment, String> {
        let addr = vs.iter().find_map(|v| match v {
            Param::Addr(a) => Some(a.clone()),
            _otherwise => None,
        });

        let mut payment = Payment {
            recipient_address: addr.ok_or(format!("Payment {} had no recipient address.", i))?,
            amount: Amount::zero(),
            memo: None,
            label: None,
            message: None,
            other_params: vec![],
        };

        for v in vs {
            match v {
                Param::Amount(a) => payment.amount = a,
                Param::Memo(m) => {
                    match payment.recipient_address {
                        RecipientAddress::Shielded(_) => payment.memo = Some(m),
                        RecipientAddress::Transparent(_) => return Err(format!("Payment {} attempted to associate a memo with a transparent recipient address", i)),
                    }
                },

                Param::Label(m) => payment.label = Some(m),
                Param::Message(m) => payment.message = Some(m),
                Param::Other(n, m) => payment.other_params.push((n, m)),
                _otherwise => {}
            }
        }

        Ok(payment)
    }

    /// Parses and consumes the leading "zcash:\[address\]" from a ZIP 321 URI.
    pub fn lead_addr<P: consensus::Parameters>(
        params: &P,
    ) -> impl Fn(&str) -> IResult<&str, Option<IndexedParam>> + '_ {
        move |input: &str| {
            map_opt(
                preceded(tag("zcash:"), take_until("?")),
                |addr_str: &str| {
                    if addr_str.is_empty() {
                        Some(None) // no address is ok, so wrap in `Some`
                    } else {
                        // `decode` returns `None` on error, which we want to
                        // then cause `map_opt` to fail.
                        RecipientAddress::decode(params, addr_str).map(|a| {
                            Some(IndexedParam {
                                param: Param::Addr(a),
                                payment_index: 0,
                            })
                        })
                    }
                },
            )(input)
        }
    }

    /// The primary parser for <name>=<value> query-string parameter pair.
    pub fn zcashparam<P: consensus::Parameters>(
        params: &P,
    ) -> impl Fn(&str) -> IResult<&str, IndexedParam> + '_ {
        move |input| {
            map_res(
                separated_pair(indexed_name, char('='), recognize(qchars)),
                move |r| to_indexed_param(params, r),
            )(input)
        }
    }

    /// Extension for the `alphanumeric0` parser which extends that parser
    /// by also permitting the characters that are members of the `allowed`
    /// string.
    fn alphanum_or(allowed: &str) -> impl (Fn(&str) -> IResult<&str, &str>) + '_ {
        move |input| {
            input.split_at_position_complete(|item| {
                let c = item.as_char();
                !(c.is_alphanum() || allowed.contains(c))
            })
        }
    }

    /// Parses valid characters which may appear in parameter values.
    pub fn qchars(input: &str) -> IResult<&str, &str> {
        alphanum_or("-._~!$'()*+,;:@%")(input)
    }

    /// Parses valid characters that may appear in parameter names.
    pub fn namechars(input: &str) -> IResult<&str, &str> {
        alphanum_or("+-")(input)
    }

    /// Parses a parameter name and its associated index.
    pub fn indexed_name(input: &str) -> IResult<&str, (&str, Option<&str>)> {
        let paramname = recognize(tuple((alpha1, namechars)));

        tuple((
            paramname,
            opt(preceded(
                char('.'),
                recognize(tuple((
                    one_of("123456789"),
                    map_opt(digit0, |s: &str| if s.len() > 3 { None } else { Some(s) }),
                ))),
            )),
        ))(input)
    }

    /// Parses a value in decimal ZEC.
    pub fn parse_amount(input: &str) -> IResult<&str, Amount> {
        map_res(
            tuple((
                digit1,
                opt(preceded(
                    char('.'),
                    map_opt(digit0, |s: &str| if s.len() > 8 { None } else { Some(s) }),
                )),
            )),
            |(whole_s, decimal_s): (&str, Option<&str>)| {
                let coins: i64 = whole_s
                    .to_string()
                    .parse::<i64>()
                    .map_err(|e| e.to_string())?;

                let zats: i64 = match decimal_s {
                    Some(d) => format!("{:0<8}", d)
                        .parse::<i64>()
                        .map_err(|e| e.to_string())?,
                    None => 0,
                };

                if coins >= 21000000 && (coins > 21000000 || zats > 0) {
                    return Err(format!(
                        "{} coins exceeds the maximum possible Zcash value.",
                        coins
                    ));
                }

                let amt = coins * COIN + zats;

                Amount::from_nonnegative_i64(amt)
                    .map_err(|_| format!("Not a valid zat amount: {}", amt))
            },
        )(input)
    }

    fn to_indexed_param<'a, P: consensus::Parameters>(
        params: &'a P,
        ((name, iopt), value): ((&str, Option<&str>), &str),
    ) -> Result<IndexedParam, String> {
        let param = match name {
            "address" => RecipientAddress::decode(params, value)
                .map(Param::Addr)
                .ok_or(format!(
                    "Could not interpret {} as a valid Zcash address.",
                    value
                )),

            "amount" => parse_amount(value)
                .map(|(_, a)| Param::Amount(a))
                .map_err(|e| e.to_string()),

            "label" => percent_decode(value.as_bytes())
                .decode_utf8()
                .map(|s| Param::Label(s.into_owned()))
                .map_err(|e| e.to_string()),

            "message" => percent_decode(value.as_bytes())
                .decode_utf8()
                .map(|s| Param::Message(s.into_owned()))
                .map_err(|e| e.to_string()),

            "memo" => memo_from_base64(value)
                .map(Param::Memo)
                .map_err(|e| format!("Decoded memo was invalid: {:?}", e)),

            other if other.starts_with("req-") => {
                Err(format!("Required parameter {} not recognized", other))
            }

            other => percent_decode(value.as_bytes())
                .decode_utf8()
                .map(|s| Param::Other(other.to_string(), s.into_owned()))
                .map_err(|e| e.to_string()),
        }?;

        let payment_index = match iopt {
            Some(istr) => istr.parse::<usize>().map(Some).map_err(|e| e.to_string()),
            None => Ok(None),
        }?;

        Ok(IndexedParam {
            param,
            payment_index: payment_index.unwrap_or(0),
        })
    }
}

#[cfg(feature = "test-dependencies")]
pub mod testing {
    use proptest::collection::btree_map;
    use proptest::collection::vec;
    use proptest::option;
    use proptest::prelude::{any, prop_compose, prop_oneof};
    use proptest::strategy::Strategy;
    use zcash_primitives::{
        consensus::TEST_NETWORK, legacy::testing::arb_transparent_addr,
        sapling::keys::testing::arb_shielded_addr,
        transaction::components::amount::testing::arb_nonnegative_amount,
    };

    use crate::address::RecipientAddress;

    use super::{MemoBytes, Payment, TransactionRequest};

    pub fn arb_addr() -> impl Strategy<Value = RecipientAddress> {
        prop_oneof![
            arb_shielded_addr().prop_map(RecipientAddress::Shielded),
            arb_transparent_addr().prop_map(RecipientAddress::Transparent),
        ]
    }

    pub const VALID_PARAMNAME: &str = "[a-zA-Z][a-zA-Z0-9+-]*";

    prop_compose! {
        pub fn arb_valid_memo()(bytes in vec(any::<u8>(), 0..512)) -> MemoBytes {
            MemoBytes::from_bytes(&bytes).unwrap()
        }
    }

    prop_compose! {
        pub fn arb_zip321_payment()(
            recipient_address in arb_addr(),
            amount in arb_nonnegative_amount(),
            memo in option::of(arb_valid_memo()),
            message in option::of(any::<String>()),
            label in option::of(any::<String>()),
            // prevent duplicates by generating a set rather than a vec
            other_params in btree_map(VALID_PARAMNAME, any::<String>(), 0..3),
            ) -> Payment {

            let is_sapling = match recipient_address {
                RecipientAddress::Transparent(_) => false,
                RecipientAddress::Shielded(_) => true,
            };

            Payment {
                recipient_address,
                amount,
                memo: memo.filter(|_| is_sapling),
                label,
                message,
                other_params: other_params.into_iter().collect(),
            }
        }
    }

    prop_compose! {
        pub fn arb_zip321_request()(payments in vec(arb_zip321_payment(), 1..10)) -> TransactionRequest {
            let mut req = TransactionRequest { payments };
            req.normalize(&TEST_NETWORK); // just to make test comparisons easier
            req
        }
    }

    prop_compose! {
        pub fn arb_zip321_uri()(req in arb_zip321_request()) -> String {
            req.to_uri(&TEST_NETWORK).unwrap()
        }
    }

    prop_compose! {
        pub fn arb_addr_str()(addr in arb_addr()) -> String {
            addr.encode(&TEST_NETWORK)
        }
    }
}

#[cfg(test)]
mod tests {
    use std::str::FromStr;
    use zcash_primitives::{
        consensus::{Parameters, TEST_NETWORK},
        memo::Memo,
        transaction::components::Amount,
    };

    use crate::address::RecipientAddress;

    use super::{
        memo_from_base64, memo_to_base64,
        parse::{parse_amount, zcashparam, Param},
        render::amount_str,
        MemoBytes, Payment, TransactionRequest,
    };
    use crate::encoding::decode_payment_address;

    #[cfg(all(test, feature = "test-dependencies"))]
    use proptest::prelude::{any, proptest};

    #[cfg(all(test, feature = "test-dependencies"))]
    use zcash_primitives::transaction::components::amount::testing::arb_nonnegative_amount;

    #[cfg(all(test, feature = "test-dependencies"))]
    use super::{
        render::{memo_param, str_param},
        testing::{arb_addr, arb_addr_str, arb_valid_memo, arb_zip321_request, arb_zip321_uri},
    };

    fn check_roundtrip(req: TransactionRequest) {
        if let Some(req_uri) = req.to_uri(&TEST_NETWORK) {
            let parsed = TransactionRequest::from_uri(&TEST_NETWORK, &req_uri).unwrap();
            assert_eq!(parsed, req);
        } else {
            panic!("Generated invalid payment request: {:?}", req);
        }
    }

    #[test]
    fn test_zip321_roundtrip_simple_amounts() {
        let amounts = vec![1u64, 1000u64, 100000u64, 100000000u64, 100000000000u64];

        for amt_u64 in amounts {
            let amt = Amount::from_u64(amt_u64).unwrap();
            let amt_str = amount_str(amt).unwrap();
            assert_eq!(amt, parse_amount(&amt_str).unwrap().1);
        }
    }

    #[test]
    fn test_zip321_parse_empty_message() {
        let fragment = "message=";

        let result = zcashparam(&TEST_NETWORK)(fragment).unwrap().1.param;
        assert_eq!(result, Param::Message("".to_string()));
    }

    #[test]
    fn test_zip321_parse_simple() {
        let uri = "zcash:ztestsapling1n65uaftvs2g7075q2x2a04shfk066u3lldzxsrprfrqtzxnhc9ps73v4lhx4l9yfxj46sl0q90k?amount=3768769.02796286&message=";
        let parse_result = TransactionRequest::from_uri(&TEST_NETWORK, &uri).unwrap();

        let expected = TransactionRequest {
            payments: vec![
                Payment {
                    recipient_address: RecipientAddress::Shielded(decode_payment_address(&TEST_NETWORK.hrp_sapling_payment_address(), "ztestsapling1n65uaftvs2g7075q2x2a04shfk066u3lldzxsrprfrqtzxnhc9ps73v4lhx4l9yfxj46sl0q90k").unwrap().unwrap()),
                    amount: Amount::from_u64(376876902796286).unwrap(),
                    memo: None,
                    label: None,
                    message: Some("".to_string()),
                    other_params: vec![],
                }
            ]
        };

        assert_eq!(parse_result, expected);
    }

    #[test]
    fn test_zip321_roundtrip_empty_message() {
        let req = TransactionRequest {
            payments: vec![
                Payment {
                    recipient_address: RecipientAddress::Shielded(decode_payment_address(TEST_NETWORK.hrp_sapling_payment_address(), "ztestsapling1n65uaftvs2g7075q2x2a04shfk066u3lldzxsrprfrqtzxnhc9ps73v4lhx4l9yfxj46sl0q90k").unwrap().unwrap()),
                    amount: Amount::from_u64(0).unwrap(),
                    memo: None,
                    label: None,
                    message: Some("".to_string()),
                    other_params: vec![]
                }
            ]
        };

        check_roundtrip(req);
    }

    #[test]
    fn test_zip321_memos() {
        let m_simple: MemoBytes = Memo::from_str("This is a simple memo.").unwrap().into();
        let m_simple_64 = memo_to_base64(&m_simple);
        assert_eq!(memo_from_base64(&m_simple_64).unwrap(), m_simple);

        let m_json: MemoBytes = Memo::from_str("{ \"key\": \"This is a JSON-structured memo.\" }")
            .unwrap()
            .into();
        let m_json_64 = memo_to_base64(&m_json);
        assert_eq!(memo_from_base64(&m_json_64).unwrap(), m_json);

        let m_unicode: MemoBytes = Memo::from_str("This is a unicode memo ✨🦄🏆🎉")
            .unwrap()
            .into();
        let m_unicode_64 = memo_to_base64(&m_unicode);
        assert_eq!(memo_from_base64(&m_unicode_64).unwrap(), m_unicode);
    }

    #[test]
    fn test_zip321_spec_valid_examples() {
        let valid_1 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=1&memo=VGhpcyBpcyBhIHNpbXBsZSBtZW1vLg&message=Thank%20you%20for%20your%20purchase";
        let v1r = TransactionRequest::from_uri(&TEST_NETWORK, &valid_1).unwrap();
        assert_eq!(
            v1r.payments.get(0).map(|p| p.amount),
            Some(Amount::from_u64(100000000).unwrap())
        );

        let valid_2 = "zcash:?address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=123.456&address.1=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=0.789&memo.1=VGhpcyBpcyBhIHVuaWNvZGUgbWVtbyDinKjwn6aE8J-PhvCfjok";
        let mut v2r = TransactionRequest::from_uri(&TEST_NETWORK, &valid_2).unwrap();
        v2r.normalize(&TEST_NETWORK);
        assert_eq!(
            v2r.payments.get(0).map(|p| p.amount),
            Some(Amount::from_u64(12345600000).unwrap())
        );
        assert_eq!(
            v2r.payments.get(1).map(|p| p.amount),
            Some(Amount::from_u64(78900000).unwrap())
        );

        // valid; amount just less than MAX_MONEY
        // 20999999.99999999
        let valid_3 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=20999999.99999999";
        let v3r = TransactionRequest::from_uri(&TEST_NETWORK, &valid_3).unwrap();
        assert_eq!(
            v3r.payments.get(0).map(|p| p.amount),
            Some(Amount::from_u64(2099999999999999u64).unwrap())
        );

        // valid; MAX_MONEY
        // 21000000
        let valid_4 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=21000000";
        let v4r = TransactionRequest::from_uri(&TEST_NETWORK, &valid_4).unwrap();
        assert_eq!(
            v4r.payments.get(0).map(|p| p.amount),
            Some(Amount::from_u64(2100000000000000u64).unwrap())
        );
    }

    #[test]
    fn test_zip321_spec_invalid_examples() {
        // invalid; missing `address=`
        let invalid_1 = "zcash:?amount=3491405.05201255&address.1=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=5740296.87793245";
        let i1r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_1);
        assert!(i1r.is_err());

        // invalid; missing `address.1=`
        let invalid_2 = "zcash:?address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=1&amount.1=2&address.2=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez";
        let i2r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_2);
        assert!(i2r.is_err());

        // invalid; `address.0=` and `amount.0=` are not permitted (leading 0s).
        let invalid_3 = "zcash:?address.0=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.0=2";
        let i3r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_3);
        assert!(i3r.is_err());

        // invalid; duplicate `amount=` field
        let invalid_4 =
            "zcash:?amount=1.234&amount=2.345&address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU";
        let i4r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_4);
        assert!(i4r.is_err());

        // invalid; duplicate `amount.1=` field
        let invalid_5 =
            "zcash:?amount.1=1.234&amount.1=2.345&address.1=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU";
        let i5r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_5);
        assert!(i5r.is_err());

        //invalid; memo associated with t-addr
        let invalid_6 = "zcash:?address=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU&amount=123.456&memo=eyAia2V5IjogIlRoaXMgaXMgYSBKU09OLXN0cnVjdHVyZWQgbWVtby4iIH0&address.1=ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez&amount.1=0.789&memo.1=VGhpcyBpcyBhIHVuaWNvZGUgbWVtbyDinKjwn6aE8J-PhvCfjok";
        let i6r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_6);
        assert!(i6r.is_err());

        // invalid; amount component exceeds an i64
        // 9223372036854775808 = i64::MAX + 1
        let invalid_7 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=9223372036854775808";
        let i7r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_7);
        assert!(i7r.is_err());

        // invalid; amount component wraps into a valid small positive i64
        // 18446744073709551624
        let invalid_7a = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=18446744073709551624";
        let i7ar = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_7a);
        assert!(i7ar.is_err());

        // invalid; amount component is MAX_MONEY
        // 21000000.00000001
        let invalid_8 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=21000000.00000001";
        let i8r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_8);
        assert!(i8r.is_err());

        // invalid; negative amount
        let invalid_9 = "zcash:ztestsapling10yy2ex5dcqkclhc7z7yrnjq2z6feyjad56ptwlfgmy77dmaqqrl9gyhprdx59qgmsnyfska2kez?amount=-1";
        let i9r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_9);
        assert!(i9r.is_err());

        // invalid; parameter index too large
        let invalid_10 =
            "zcash:?amount.10000=1.23&address.10000=tmEZhbWHTpdKMw5it8YDspUXSMGQyFwovpU";
        let i10r = TransactionRequest::from_uri(&TEST_NETWORK, &invalid_10);
        assert!(i10r.is_err());
    }

    #[cfg(all(test, feature = "test-dependencies"))]
    proptest! {
        #[test]
        fn prop_zip321_roundtrip_address(addr in arb_addr()) {
            let a = addr.encode(&TEST_NETWORK);
            assert_eq!(RecipientAddress::decode(&TEST_NETWORK, &a), Some(addr));
        }

        #[test]
        fn prop_zip321_roundtrip_address_str(a in arb_addr_str()) {
            let addr = RecipientAddress::decode(&TEST_NETWORK, &a).unwrap();
            assert_eq!(addr.encode(&TEST_NETWORK), a);
        }

        #[test]
        fn prop_zip321_roundtrip_amount(amt in arb_nonnegative_amount()) {
            let amt_str = amount_str(amt).unwrap();
            assert_eq!(amt, parse_amount(&amt_str).unwrap().1);
        }

        #[test]
        fn prop_zip321_roundtrip_str_param(
            message in any::<String>(), i in proptest::option::of(0usize..2000)) {
            let fragment = str_param("message", &message, i);
            let (rest, iparam) = zcashparam(&TEST_NETWORK)(&fragment).unwrap();
            assert_eq!(rest, "");
            assert_eq!(iparam.param, Param::Message(message));
            assert_eq!(iparam.payment_index, i.unwrap_or(0));
        }

        #[test]
        fn prop_zip321_roundtrip_memo_param(
            memo in arb_valid_memo(), i in proptest::option::of(0usize..2000)) {
            let fragment = memo_param(&memo, i);
            let (rest, iparam) = zcashparam(&TEST_NETWORK)(&fragment).unwrap();
            assert_eq!(rest, "");
            assert_eq!(iparam.param, Param::Memo(memo));
            assert_eq!(iparam.payment_index, i.unwrap_or(0));
        }

        #[test]
        fn prop_zip321_roundtrip_request(mut req in arb_zip321_request()) {
            if let Some(req_uri) = req.to_uri(&TEST_NETWORK) {
                let mut parsed = TransactionRequest::from_uri(&TEST_NETWORK, &req_uri).unwrap();
                assert!(TransactionRequest::normalize_and_eq(&TEST_NETWORK, &mut parsed, &mut req));
            } else {
                panic!("Generated invalid payment request: {:?}", req);
            }
        }

        #[test]
        fn prop_zip321_roundtrip_uri(uri in arb_zip321_uri()) {
            let mut parsed = TransactionRequest::from_uri(&TEST_NETWORK, &uri).unwrap();
            parsed.normalize(&TEST_NETWORK);
            let serialized = parsed.to_uri(&TEST_NETWORK);
            assert_eq!(serialized, Some(uri))
        }
    }
}