hyperswitch/crates/euclid/src/backend/vir_interpreter.rs

pub mod types;

use std::fmt::Debug;

use serde::{Deserialize, Serialize};

use crate::{
    backend::{self, inputs, EuclidBackend},
    frontend::{
        ast,
        dir::{self, EuclidDirFilter},
        vir,
    },
};

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct VirInterpreterBackend<O> {
    program: vir::ValuedProgram<O>,
}

impl<O> VirInterpreterBackend<O>
where
    O: Clone,
{
    #[inline]
    fn eval_comparison(comp: &vir::ValuedComparison, ctx: &types::Context) -> bool {
        match &comp.logic {
            vir::ValuedComparisonLogic::PositiveDisjunction => {
                comp.values.iter().any(|v| ctx.check_presence(v))
            }
            vir::ValuedComparisonLogic::NegativeConjunction => {
                comp.values.iter().all(|v| !ctx.check_presence(v))
            }
        }
    }

    #[inline]
    fn eval_condition(cond: &vir::ValuedIfCondition, ctx: &types::Context) -> bool {
        cond.iter().all(|comp| Self::eval_comparison(comp, ctx))
    }

    fn eval_statement(stmt: &vir::ValuedIfStatement, ctx: &types::Context) -> bool {
        if Self::eval_condition(&stmt.condition, ctx) {
            {
                stmt.nested.as_ref().map_or(true, |nested_stmts| {
                    nested_stmts.iter().any(|s| Self::eval_statement(s, ctx))
                })
            }
        } else {
            false
        }
    }

    fn eval_rule(rule: &vir::ValuedRule<O>, ctx: &types::Context) -> bool {
        rule.statements
            .iter()
            .any(|stmt| Self::eval_statement(stmt, ctx))
    }

    fn eval_program(
        program: &vir::ValuedProgram<O>,
        ctx: &types::Context,
    ) -> backend::BackendOutput<O> {
        program
            .rules
            .iter()
            .find(|rule| Self::eval_rule(rule, ctx))
            .map_or_else(
                || backend::BackendOutput {
                    connector_selection: program.default_selection.clone(),
                    rule_name: None,
                },
                |rule| backend::BackendOutput {
                    connector_selection: rule.connector_selection.clone(),
                    rule_name: Some(rule.name.clone()),
                },
            )
    }
}

impl<O> EuclidBackend<O> for VirInterpreterBackend<O>
where
    O: Clone + EuclidDirFilter,
{
    type Error = types::VirInterpreterError;

    fn with_program(program: ast::Program<O>) -> Result<Self, Self::Error> {
        let dir_program = ast::lowering::lower_program(program)
            .map_err(types::VirInterpreterError::LoweringError)?;

        let vir_program = dir::lowering::lower_program(dir_program)
            .map_err(types::VirInterpreterError::LoweringError)?;

        Ok(Self {
            program: vir_program,
        })
    }

    fn execute(
        &self,
        input: inputs::BackendInput,
    ) -> Result<backend::BackendOutput<O>, Self::Error> {
        let ctx = types::Context::from_input(input);
        Ok(Self::eval_program(&self.program, &ctx))
    }
}
#[cfg(all(test, feature = "ast_parser"))]
mod test {
    #![allow(clippy::expect_used)]
    use common_utils::types::MinorUnit;
    use rustc_hash::FxHashMap;

    use super::*;
    use crate::{enums, types::DummyOutput};

    #[test]
    fn test_execution() {
        let program_str = r#"
        default: [ "stripe",  "adyen"]

        rule_1: ["stripe"]
        {
            pay_later = klarna
        }

        rule_2: ["adyen"]
        {
            pay_later = affirm
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                card_bin: None,
                currency: enums::Currency::USD,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_2");
    }
    #[test]
    fn test_payment_type() {
        let program_str = r#"
        default: ["stripe", "adyen"]
        rule_1: ["stripe"]
        {
           payment_type = setup_mandate
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: Some("123456".to_string()),
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: Some(enums::PaymentType::SetupMandate),
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }

    #[test]
    fn test_ppt_flow() {
        let program_str = r#"
        default: ["stripe", "adyen"]
        rule_1: ["stripe"]
        {
           payment_type = ppt_mandate
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: Some("123456".to_string()),
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: Some(enums::PaymentType::PptMandate),
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }

    #[test]
    fn test_mandate_type() {
        let program_str = r#"
        default: ["stripe", "adyen"]
        rule_1: ["stripe"]
        {
           mandate_type = single_use
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: Some("123456".to_string()),
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: Some(enums::MandateType::SingleUse),
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }

    #[test]
    fn test_mandate_acceptance_type() {
        let program_str = r#"
        default: ["stripe","adyen"]
        rule_1: ["stripe"]
        {
           mandate_acceptance_type = online
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: Some("123456".to_string()),
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: Some(enums::MandateAcceptanceType::Online),
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }
    #[test]
    fn test_card_bin() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           card_bin="123456"
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: Some("123456".to_string()),
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }
    #[test]
    fn test_payment_amount() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           amount = 32
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: None,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }
    #[test]
    fn test_payment_method() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           payment_method = pay_later
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: None,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }
    #[test]
    fn test_future_usage() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           setup_future_usage = off_session
        }
        "#;

        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                currency: enums::Currency::USD,
                card_bin: None,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: Some(enums::SetupFutureUsage::OffSession),
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }

    #[test]
    fn test_metadata_execution() {
        let program_str = r#"
        default: ["stripe"," adyen"]

        rule_1: ["stripe"]
        {
        "metadata_key" = "arbitrary meta"
        }
        "#;
        let mut meta_map = FxHashMap::default();
        meta_map.insert("metadata_key".to_string(), "arbitrary meta".to_string());
        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp = inputs::BackendInput {
            metadata: Some(meta_map),
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(32),
                card_bin: None,
                currency: enums::Currency::USD,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };

        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result = backend.execute(inp).expect("Execution");
        assert_eq!(result.rule_name.expect("Rule Name").as_str(), "rule_1");
    }

    #[test]
    fn test_less_than_operator() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           amount>=123
        }
        "#;
        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp_greater = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(150),
                card_bin: None,
                currency: enums::Currency::USD,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };
        let mut inp_equal = inp_greater.clone();
        inp_equal.payment.amount = MinorUnit::new(123);
        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result_greater = backend.execute(inp_greater).expect("Execution");
        let result_equal = backend.execute(inp_equal).expect("Execution");
        assert_eq!(
            result_equal.rule_name.expect("Rule Name").as_str(),
            "rule_1"
        );
        assert_eq!(
            result_greater.rule_name.expect("Rule Name").as_str(),
            "rule_1"
        );
    }

    #[test]
    fn test_greater_than_operator() {
        let program_str = r#"
        default: ["stripe", "adyen"]

        rule_1: ["stripe"]
        {
           amount<=123
        }
        "#;
        let (_, program) = ast::parser::program::<DummyOutput>(program_str).expect("Program");
        let inp_lower = inputs::BackendInput {
            metadata: None,
            payment: inputs::PaymentInput {
                amount: MinorUnit::new(120),
                card_bin: None,
                currency: enums::Currency::USD,
                authentication_type: Some(enums::AuthenticationType::NoThreeDs),
                capture_method: Some(enums::CaptureMethod::Automatic),
                business_country: Some(enums::Country::UnitedStatesOfAmerica),
                billing_country: Some(enums::Country::France),
                business_label: None,
                setup_future_usage: None,
            },
            payment_method: inputs::PaymentMethodInput {
                payment_method: Some(enums::PaymentMethod::PayLater),
                payment_method_type: Some(enums::PaymentMethodType::Affirm),
                card_network: None,
            },
            mandate: inputs::MandateData {
                mandate_acceptance_type: None,
                mandate_type: None,
                payment_type: None,
            },
            acquirer_data: None,
            customer_device_data: None,
            issuer_data: None,
        };
        let mut inp_equal = inp_lower.clone();
        inp_equal.payment.amount = MinorUnit::new(123);
        let backend = VirInterpreterBackend::<DummyOutput>::with_program(program).expect("Program");
        let result_equal = backend.execute(inp_equal).expect("Execution");
        let result_lower = backend.execute(inp_lower).expect("Execution");
        assert_eq!(
            result_equal.rule_name.expect("Rule Name").as_str(),
            "rule_1"
        );
        assert_eq!(
            result_lower.rule_name.expect("Rule Name").as_str(),
            "rule_1"
        );
    }
}