helios-fhirpath 0.2.0

//! Data models for FHIRPath server request and response handling
//!
//! This module defines the structures used for the FHIRPath server API,
//! following the specification in server-api.md for the fhirpath-lab
//! integration.

use serde::{Deserialize, Serialize};
use serde_json::Value;

// Use the ParameterValueAccessor trait from helios_fhir
use helios_fhir::ParameterValueAccessor;

/// Type alias for the version-independent Parameters container.
///
/// This alias provides backward compatibility while using the unified
/// VersionIndependentParameters from the helios_fhir crate.
pub type FhirPathParameters = helios_fhir::VersionIndependentParameters;

/// Individual parameter in the Parameters resource
#[derive(Debug, Deserialize, Serialize)]
pub struct Parameter {
    /// Name of the parameter
    pub name: String,

    /// String value (for simple parameters)
    #[serde(rename = "valueString", skip_serializing_if = "Option::is_none")]
    pub value_string: Option<String>,

    /// Boolean value
    #[serde(rename = "valueBoolean", skip_serializing_if = "Option::is_none")]
    pub value_boolean: Option<bool>,

    /// Resource value
    #[serde(skip_serializing_if = "Option::is_none")]
    pub resource: Option<Value>,

    /// Multi-part parameters (for variables)
    #[serde(skip_serializing_if = "Option::is_none")]
    pub part: Option<Vec<ParameterPart>>,
}

/// Part of a multi-part parameter
#[derive(Debug, Deserialize, Serialize)]
pub struct ParameterPart {
    /// Name of the part
    pub name: String,

    /// String value
    #[serde(rename = "valueString", skip_serializing_if = "Option::is_none")]
    pub value_string: Option<String>,

    /// Any other value type
    #[serde(flatten)]
    pub value: Option<Value>,
}

/// Extracted parameters for processing
#[derive(Debug, Default)]
pub struct ExtractedParameters {
    /// The context expression to execute first
    pub context: Option<String>,

    /// The FHIRPath expression to execute
    pub expression: Option<String>,

    /// Whether to validate the expression
    pub validate: bool,

    /// Variables to pass to the expression
    pub variables: Vec<Variable>,

    /// The resource to execute against
    pub resource: Option<Value>,

    /// Terminology server URL
    pub terminology_server: Option<String>,
}

/// Variable definition
#[derive(Debug, Clone)]
pub struct Variable {
    /// Variable name
    pub name: String,

    /// Variable value
    pub value: Value,
}

/// Output result part
#[derive(Debug, Serialize)]
pub struct ResultPart {
    /// Name of the part (data type or "trace")
    pub name: String,

    /// String value for context path
    #[serde(rename = "valueString", skip_serializing_if = "Option::is_none")]
    pub value_string: Option<String>,

    /// Parts for complex results
    #[serde(skip_serializing_if = "Option::is_none")]
    pub part: Option<Vec<ResultValue>>,

    /// Extension for non-representable values
    #[serde(skip_serializing_if = "Option::is_none")]
    pub extension: Option<Vec<Extension>>,
}

/// Result value within a part
#[derive(Debug, Serialize)]
pub struct ResultValue {
    /// Name (data type)
    pub name: String,

    /// Various value types
    #[serde(rename = "valueString", skip_serializing_if = "Option::is_none")]
    pub value_string: Option<String>,

    #[serde(rename = "valueBoolean", skip_serializing_if = "Option::is_none")]
    pub value_boolean: Option<bool>,

    #[serde(rename = "valueInteger", skip_serializing_if = "Option::is_none")]
    pub value_integer: Option<i64>,

    #[serde(rename = "valueDecimal", skip_serializing_if = "Option::is_none")]
    pub value_decimal: Option<f64>,

    #[serde(rename = "valueDate", skip_serializing_if = "Option::is_none")]
    pub value_date: Option<String>,

    #[serde(rename = "valueDateTime", skip_serializing_if = "Option::is_none")]
    pub value_date_time: Option<String>,

    #[serde(rename = "valueTime", skip_serializing_if = "Option::is_none")]
    pub value_time: Option<String>,

    #[serde(rename = "valueQuantity", skip_serializing_if = "Option::is_none")]
    pub value_quantity: Option<Value>,

    #[serde(rename = "valueHumanName", skip_serializing_if = "Option::is_none")]
    pub value_human_name: Option<Value>,

    /// Extension for JSON representation of complex values
    #[serde(skip_serializing_if = "Option::is_none")]
    pub extension: Option<Vec<Extension>>,
}

/// Extension for JSON values that can't be represented as FHIR types
#[derive(Debug, Serialize)]
pub struct Extension {
    /// Extension URL
    pub url: String,

    /// String value containing JSON
    #[serde(rename = "valueString")]
    pub value_string: String,
}

/// Helper to create JSON value extension
pub fn create_json_extension(value: &Value) -> Extension {
    Extension {
        url: "http://fhir.forms-lab.com/StructureDefinition/json-value".to_string(),
        value_string: serde_json::to_string_pretty(value).unwrap_or_default(),
    }
}

/// Extract parameters from the input Parameters resource
pub fn extract_parameters(params: FhirPathParameters) -> Result<ExtractedParameters, String> {
    let mut extracted = ExtractedParameters::default();

    // Process parameters based on version
    match params {
        #[cfg(feature = "R4")]
        FhirPathParameters::R4(parameters) => {
            extract_parameters_from_r4(parameters, &mut extracted)?;
        }
        #[cfg(feature = "R4B")]
        FhirPathParameters::R4B(parameters) => {
            extract_parameters_from_r4b(parameters, &mut extracted)?;
        }
        #[cfg(feature = "R5")]
        FhirPathParameters::R5(parameters) => {
            extract_parameters_from_r5(parameters, &mut extracted)?;
        }
        #[cfg(feature = "R6")]
        FhirPathParameters::R6(parameters) => {
            extract_parameters_from_r6(parameters, &mut extracted)?;
        }
        #[allow(unreachable_patterns)]
        _ => {
            return Err(
                "FHIR version of Parameters resource is not enabled in this build".to_string(),
            );
        }
    }

    if extracted.expression.is_none() {
        return Err("Missing required parameter: expression".to_string());
    }

    if extracted.resource.is_none() {
        return Err("Missing required parameter: resource".to_string());
    }

    Ok(extracted)
}

#[cfg(feature = "R4")]
fn extract_parameters_from_r4(
    parameters: helios_fhir::r4::Parameters,
    extracted: &mut ExtractedParameters,
) -> Result<(), String> {
    for param in parameters.parameter.unwrap_or_default() {
        process_parameter_r4(&param, extracted)?;
    }
    Ok(())
}

#[cfg(feature = "R4")]
fn process_parameter_r4(
    param: &helios_fhir::r4::ParametersParameter,
    extracted: &mut ExtractedParameters,
) -> Result<(), String> {
    let name = param.name.value.as_deref().unwrap_or("");

    match name {
        "context" => {
            extracted.context = param
                .value
                .as_ref()
                .and_then(|v| v.as_string())
                .map(|s| s.to_string());
        }
        "expression" => {
            extracted.expression = param
                .value
                .as_ref()
                .and_then(|v| v.as_string())
                .map(|s| s.to_string());
        }
        "validate" => {
            extracted.validate = param
                .value
                .as_ref()
                .and_then(|v| v.as_boolean())
                .unwrap_or(false);
        }
        "variables" => {
            if let Some(parts) = &param.part {
                for part in parts {
                    if let Some(name) = &part.name.value {
                        let value = if let Some(val) = &part.value {
                            // Convert parameter value to JSON
                            parameter_value_to_json_r4(val)
                        } else {
                            Value::Null
                        };

                        extracted.variables.push(Variable {
                            name: name.to_string(),
                            value,
                        });
                    }
                }
            }
        }
        "resource" => {
            extracted.resource = param
                .resource
                .as_ref()
                .and_then(|r| serde_json::to_value(r).ok());
        }
        "terminologyServer" => {
            extracted.terminology_server = param
                .value
                .as_ref()
                .and_then(|v| v.as_string())
                .map(|s| s.to_string());
        }
        _ => {
            // Ignore unknown parameters
        }
    }

    Ok(())
}

#[cfg(feature = "R4")]
fn parameter_value_to_json_r4(value: &helios_fhir::r4::ParametersParameterValue) -> Value {
    // Convert FHIR parameter value to JSON
    // This is a simplified conversion - in production, you'd handle all value types
    match value {
        helios_fhir::r4::ParametersParameterValue::String(s) => s
            .value
            .as_ref()
            .map(|v| Value::String(v.clone()))
            .unwrap_or(Value::Null),
        helios_fhir::r4::ParametersParameterValue::Boolean(b) => {
            b.value.map(Value::Bool).unwrap_or(Value::Null)
        }
        helios_fhir::r4::ParametersParameterValue::Integer(i) => i
            .value
            .map(|v| Value::Number(serde_json::Number::from(v)))
            .unwrap_or(Value::Null),
        helios_fhir::r4::ParametersParameterValue::Decimal(d) => {
            serde_json::to_value(d).unwrap_or(Value::Null)
        }
        _ => {
            // For other types, serialize to JSON
            serde_json::to_value(value).unwrap_or(Value::Null)
        }
    }
}

#[cfg(feature = "R4B")]
fn extract_parameters_from_r4b(
    parameters: helios_fhir::r4b::Parameters,
    extracted: &mut ExtractedParameters,
) -> Result<(), String> {
    for param in parameters.parameter.unwrap_or_default() {
        let name = param.name.value.as_deref().unwrap_or("");

        match name {
            "context" => {
                extracted.context = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "expression" => {
                extracted.expression = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "validate" => {
                extracted.validate = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_boolean())
                    .unwrap_or(false);
            }
            "variables" => {
                if let Some(parts) = &param.part {
                    for part in parts {
                        if let Some(name) = &part.name.value {
                            let value = if let Some(val) = &part.value {
                                parameter_value_to_json_r4b(val)
                            } else {
                                Value::Null
                            };

                            extracted.variables.push(Variable {
                                name: name.to_string(),
                                value,
                            });
                        }
                    }
                }
            }
            "resource" => {
                extracted.resource = param
                    .resource
                    .as_ref()
                    .and_then(|r| serde_json::to_value(r).ok());
            }
            "terminologyServer" => {
                extracted.terminology_server = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            _ => {}
        }
    }
    Ok(())
}

#[cfg(feature = "R4B")]
fn parameter_value_to_json_r4b(value: &helios_fhir::r4b::ParametersParameterValue) -> Value {
    match value {
        helios_fhir::r4b::ParametersParameterValue::String(s) => s
            .value
            .as_ref()
            .map(|v| Value::String(v.clone()))
            .unwrap_or(Value::Null),
        helios_fhir::r4b::ParametersParameterValue::Boolean(b) => {
            b.value.map(Value::Bool).unwrap_or(Value::Null)
        }
        helios_fhir::r4b::ParametersParameterValue::Integer(i) => i
            .value
            .map(|v| Value::Number(serde_json::Number::from(v)))
            .unwrap_or(Value::Null),
        helios_fhir::r4b::ParametersParameterValue::Decimal(d) => {
            serde_json::to_value(d).unwrap_or(Value::Null)
        }
        _ => serde_json::to_value(value).unwrap_or(Value::Null),
    }
}

#[cfg(feature = "R5")]
fn extract_parameters_from_r5(
    parameters: helios_fhir::r5::Parameters,
    extracted: &mut ExtractedParameters,
) -> Result<(), String> {
    for param in parameters.parameter.unwrap_or_default() {
        let name = param.name.value.as_deref().unwrap_or("");

        match name {
            "context" => {
                extracted.context = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "expression" => {
                extracted.expression = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "validate" => {
                extracted.validate = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_boolean())
                    .unwrap_or(false);
            }
            "variables" => {
                if let Some(parts) = &param.part {
                    for part in parts {
                        if let Some(name) = &part.name.value {
                            let value = if let Some(val) = &part.value {
                                parameter_value_to_json_r5(val)
                            } else {
                                Value::Null
                            };

                            extracted.variables.push(Variable {
                                name: name.to_string(),
                                value,
                            });
                        }
                    }
                }
            }
            "resource" => {
                extracted.resource = param
                    .resource
                    .as_ref()
                    .and_then(|r| serde_json::to_value(r).ok());
            }
            "terminologyServer" => {
                extracted.terminology_server = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            _ => {}
        }
    }
    Ok(())
}

#[cfg(feature = "R5")]
fn parameter_value_to_json_r5(value: &helios_fhir::r5::ParametersParameterValue) -> Value {
    match value {
        helios_fhir::r5::ParametersParameterValue::String(s) => s
            .value
            .as_ref()
            .map(|v| Value::String(v.clone()))
            .unwrap_or(Value::Null),
        helios_fhir::r5::ParametersParameterValue::Boolean(b) => {
            b.value.map(Value::Bool).unwrap_or(Value::Null)
        }
        helios_fhir::r5::ParametersParameterValue::Integer(i) => i
            .value
            .map(|v| Value::Number(serde_json::Number::from(v)))
            .unwrap_or(Value::Null),
        helios_fhir::r5::ParametersParameterValue::Decimal(d) => {
            serde_json::to_value(d).unwrap_or(Value::Null)
        }
        _ => serde_json::to_value(value).unwrap_or(Value::Null),
    }
}

#[cfg(feature = "R6")]
fn extract_parameters_from_r6(
    parameters: helios_fhir::r6::Parameters,
    extracted: &mut ExtractedParameters,
) -> Result<(), String> {
    for param in parameters.parameter.unwrap_or_default() {
        let name = param.name.value.as_deref().unwrap_or("");

        match name {
            "context" => {
                extracted.context = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "expression" => {
                extracted.expression = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            "validate" => {
                extracted.validate = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_boolean())
                    .unwrap_or(false);
            }
            "variables" => {
                if let Some(parts) = &param.part {
                    for part in parts {
                        if let Some(name) = &part.name.value {
                            let value = if let Some(val) = &part.value {
                                parameter_value_to_json_r6(val)
                            } else {
                                Value::Null
                            };

                            extracted.variables.push(Variable {
                                name: name.to_string(),
                                value,
                            });
                        }
                    }
                }
            }
            "resource" => {
                extracted.resource = param
                    .resource
                    .as_ref()
                    .and_then(|r| serde_json::to_value(r).ok());
            }
            "terminologyServer" => {
                extracted.terminology_server = param
                    .value
                    .as_ref()
                    .and_then(|v| v.as_string())
                    .map(|s| s.to_string());
            }
            _ => {}
        }
    }
    Ok(())
}

#[cfg(feature = "R6")]
fn parameter_value_to_json_r6(value: &helios_fhir::r6::ParametersParameterValue) -> Value {
    match value {
        helios_fhir::r6::ParametersParameterValue::String(s) => s
            .value
            .as_ref()
            .map(|v| Value::String(v.clone()))
            .unwrap_or(Value::Null),
        helios_fhir::r6::ParametersParameterValue::Boolean(b) => {
            b.value.map(Value::Bool).unwrap_or(Value::Null)
        }
        helios_fhir::r6::ParametersParameterValue::Integer(i) => i
            .value
            .map(|v| Value::Number(serde_json::Number::from(v)))
            .unwrap_or(Value::Null),
        helios_fhir::r6::ParametersParameterValue::Decimal(d) => {
            serde_json::to_value(d).unwrap_or(Value::Null)
        }
        _ => serde_json::to_value(value).unwrap_or(Value::Null),
    }
}