sql-orm 0.1.0

use crate::AuditEntity;
use sql_orm_core::{ColumnMetadata, ColumnValue, EntityMetadata, OrmError};
use std::collections::BTreeSet;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
/// Persistence operation currently requesting audit values.
pub enum AuditOperation {
    /// Insert path for a new row.
    Insert,
    /// Update path for an existing row.
    Update,
}

#[derive(Debug, Clone, Default, PartialEq)]
/// Low-level request-scoped audit values.
///
/// Most applications can use `with_audit_values(Audit { ... })` with a struct
/// derived from `AuditFields`. This type remains available for callers that
/// need to construct `ColumnValue`s manually.
pub struct AuditRequestValues {
    values: Vec<ColumnValue>,
}

impl AuditRequestValues {
    /// Creates request-scoped audit values from explicit column values.
    pub fn new(values: Vec<ColumnValue>) -> Self {
        Self { values }
    }

    /// Returns the raw audit column values.
    pub fn values(&self) -> &[ColumnValue] {
        &self.values
    }
}

#[derive(Debug, Clone, Copy)]
/// Context passed to an `AuditProvider`.
pub struct AuditContext<'a> {
    /// Entity metadata for the row being inserted or updated.
    pub entity: &'static EntityMetadata,
    /// Persistence operation requesting values.
    pub operation: AuditOperation,
    /// Request values already configured on the shared connection.
    pub request_values: Option<&'a AuditRequestValues>,
}

/// Runtime provider for audit column values.
///
/// Providers are consulted by insert/update paths for entities that declare
/// `#[orm(audit = Audit)]`. Explicit mutation values win over request values,
/// and request values win over provider values.
pub trait AuditProvider: Send + Sync {
    /// Returns candidate audit values for the current context.
    fn values(&self, context: AuditContext<'_>) -> Result<Vec<ColumnValue>, OrmError>;
}

/// Typed audit value conversion generated by `#[derive(AuditFields)]`.
pub trait AuditValues {
    /// Consumes the typed audit struct and returns physical column values.
    fn audit_values(self) -> Vec<ColumnValue>;
}

pub(crate) fn apply_audit_values<E: AuditEntity>(
    operation: AuditOperation,
    values: Vec<ColumnValue>,
    audit_provider: Option<&dyn AuditProvider>,
    request_values: Option<&AuditRequestValues>,
) -> Result<Vec<ColumnValue>, OrmError> {
    validate_no_duplicate_columns("audit values", &values)?;

    let Some(policy) = E::audit_policy() else {
        return Ok(values);
    };

    let context = AuditContext {
        entity: E::metadata(),
        operation,
        request_values,
    };
    let provider_values = match audit_provider {
        Some(provider) => {
            let values = provider.values(context)?;
            validate_no_duplicate_columns("audit provider values", &values)?;
            values
        }
        None => Vec::new(),
    };

    if let Some(request_values) = request_values {
        validate_no_duplicate_columns("audit request values", request_values.values())?;
    }

    let mut resolved = values;
    let mut seen = resolved
        .iter()
        .map(|value| value.column_name)
        .collect::<BTreeSet<_>>();

    for value in &resolved {
        if let Some(column) = policy
            .columns
            .iter()
            .find(|column| column.column_name == value.column_name)
        {
            validate_audit_column_value(operation, column, &value.value)?;
        }
    }

    if let Some(request_values) = request_values {
        append_missing_audit_values(
            operation,
            policy.columns,
            &mut resolved,
            &mut seen,
            request_values.values(),
        )?;
    }

    append_missing_audit_values(
        operation,
        policy.columns,
        &mut resolved,
        &mut seen,
        &provider_values,
    )?;

    Ok(resolved)
}

#[doc(hidden)]
pub fn resolve_audit_values(
    values: Vec<ColumnValue>,
    context: AuditContext<'_>,
    audit_provider: Option<&dyn AuditProvider>,
) -> Result<Vec<ColumnValue>, OrmError> {
    validate_no_duplicate_columns("audit values", &values)?;

    let mut resolved = values;
    let mut seen = resolved
        .iter()
        .map(|value| value.column_name)
        .collect::<BTreeSet<_>>();

    if let Some(request_values) = context.request_values {
        validate_no_duplicate_columns("audit request values", request_values.values())?;
        append_missing_values(&mut resolved, &mut seen, request_values.values());
    }

    if let Some(provider) = audit_provider {
        let provider_values = provider.values(context)?;
        validate_no_duplicate_columns("audit provider values", &provider_values)?;
        append_missing_values(&mut resolved, &mut seen, &provider_values);
    }

    Ok(resolved)
}

fn append_missing_audit_values(
    operation: AuditOperation,
    columns: &'static [ColumnMetadata],
    resolved: &mut Vec<ColumnValue>,
    seen: &mut BTreeSet<&'static str>,
    values: &[ColumnValue],
) -> Result<(), OrmError> {
    for value in values {
        let Some(column) = columns
            .iter()
            .find(|column| column.column_name == value.column_name)
        else {
            continue;
        };

        validate_audit_column_value(operation, column, &value.value)?;

        if seen.insert(value.column_name) {
            resolved.push(value.clone());
        }
    }

    Ok(())
}

fn validate_audit_column_value(
    operation: AuditOperation,
    column: &ColumnMetadata,
    value: &sql_orm_core::SqlValue,
) -> Result<(), OrmError> {
    match operation {
        AuditOperation::Insert if !column.insertable => {
            return Err(OrmError::new(format!(
                "audit insert column `{}` is not insertable",
                column.column_name
            )));
        }
        AuditOperation::Update if !column.updatable => {
            return Err(OrmError::new(format!(
                "audit update column `{}` is not updatable",
                column.column_name
            )));
        }
        _ => {}
    }

    if value.is_null() && !column.nullable {
        return Err(OrmError::new(format!(
            "audit column `{}` is not nullable",
            column.column_name
        )));
    }

    Ok(())
}

fn validate_no_duplicate_columns(label: &str, values: &[ColumnValue]) -> Result<(), OrmError> {
    let mut seen = BTreeSet::new();

    for value in values {
        if !seen.insert(value.column_name) {
            return Err(OrmError::new(format!(
                "duplicate column `{}` in {label}",
                value.column_name
            )));
        }
    }

    Ok(())
}

fn append_missing_values(
    resolved: &mut Vec<ColumnValue>,
    seen: &mut BTreeSet<&'static str>,
    values: &[ColumnValue],
) {
    for value in values {
        if seen.insert(value.column_name) {
            resolved.push(value.clone());
        }
    }
}

#[cfg(test)]
mod tests {
    use super::{
        AuditContext, AuditOperation, AuditProvider, AuditRequestValues, apply_audit_values,
        resolve_audit_values,
    };
    use crate::AuditEntity;
    use sql_orm_core::{
        ColumnMetadata, ColumnValue, Entity, EntityMetadata, EntityPolicyMetadata, OrmError,
        PrimaryKeyMetadata, SqlServerType, SqlValue,
    };

    struct TestAuditedEntity;

    static TEST_ENTITY_COLUMNS: [ColumnMetadata; 1] = [ColumnMetadata {
        rust_field: "id",
        column_name: "id",
        renamed_from: None,
        sql_type: SqlServerType::BigInt,
        nullable: false,
        primary_key: true,
        identity: None,
        default_sql: None,
        computed_sql: None,
        rowversion: false,
        insertable: false,
        updatable: false,
        max_length: None,
        precision: None,
        scale: None,
    }];

    static TEST_ENTITY_METADATA: EntityMetadata = EntityMetadata {
        rust_name: "AuditedEntity",
        schema: "dbo",
        table: "audited_entities",
        renamed_from: None,
        columns: &TEST_ENTITY_COLUMNS,
        primary_key: PrimaryKeyMetadata::new(None, &["id"]),
        indexes: &[],
        foreign_keys: &[],
        navigations: &[],
    };

    static TEST_AUDIT_COLUMNS: [ColumnMetadata; 3] = [
        ColumnMetadata {
            rust_field: "created_at",
            column_name: "created_at",
            renamed_from: None,
            sql_type: SqlServerType::DateTime2,
            nullable: false,
            primary_key: false,
            identity: None,
            default_sql: Some("SYSUTCDATETIME()"),
            computed_sql: None,
            rowversion: false,
            insertable: false,
            updatable: false,
            max_length: None,
            precision: None,
            scale: None,
        },
        ColumnMetadata {
            rust_field: "created_by",
            column_name: "created_by",
            renamed_from: None,
            sql_type: SqlServerType::BigInt,
            nullable: false,
            primary_key: false,
            identity: None,
            default_sql: None,
            computed_sql: None,
            rowversion: false,
            insertable: true,
            updatable: true,
            max_length: None,
            precision: None,
            scale: None,
        },
        ColumnMetadata {
            rust_field: "updated_by",
            column_name: "updated_by",
            renamed_from: None,
            sql_type: SqlServerType::NVarChar,
            nullable: true,
            primary_key: false,
            identity: None,
            default_sql: None,
            computed_sql: None,
            rowversion: false,
            insertable: true,
            updatable: true,
            max_length: Some(120),
            precision: None,
            scale: None,
        },
    ];

    impl Entity for TestAuditedEntity {
        fn metadata() -> &'static EntityMetadata {
            &TEST_ENTITY_METADATA
        }
    }

    impl AuditEntity for TestAuditedEntity {
        fn audit_policy() -> Option<EntityPolicyMetadata> {
            Some(EntityPolicyMetadata::new("audit", &TEST_AUDIT_COLUMNS))
        }
    }

    struct FixedAuditProvider;

    impl AuditProvider for FixedAuditProvider {
        fn values(&self, context: AuditContext<'_>) -> Result<Vec<ColumnValue>, OrmError> {
            assert_eq!(context.entity.rust_name, "AuditedEntity");
            assert_eq!(context.operation, AuditOperation::Insert);
            assert!(context.request_values.is_some());

            Ok(vec![
                ColumnValue::new(
                    "created_at",
                    SqlValue::String("provider-created-at".to_string()),
                ),
                ColumnValue::new(
                    "updated_by",
                    SqlValue::String("provider-updated-by".to_string()),
                ),
            ])
        }
    }

    fn context<'a>(request_values: Option<&'a AuditRequestValues>) -> AuditContext<'a> {
        AuditContext {
            entity: &TEST_ENTITY_METADATA,
            operation: AuditOperation::Insert,
            request_values,
        }
    }

    #[test]
    fn apply_audit_values_completes_only_missing_insertable_audit_columns() {
        let request_values = AuditRequestValues::new(vec![
            ColumnValue::new("created_by", SqlValue::I64(7)),
            ColumnValue::new(
                "ignored",
                SqlValue::String("not an audit column".to_string()),
            ),
        ]);

        struct Provider;

        impl AuditProvider for Provider {
            fn values(&self, _context: AuditContext<'_>) -> Result<Vec<ColumnValue>, OrmError> {
                Ok(vec![
                    ColumnValue::new("created_by", SqlValue::I64(9)),
                    ColumnValue::new("updated_by", SqlValue::String("provider".to_string())),
                    ColumnValue::new("other", SqlValue::String("not an audit column".to_string())),
                ])
            }
        }

        let values = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Insert,
            vec![ColumnValue::new(
                "name",
                SqlValue::String("existing".to_string()),
            )],
            Some(&Provider),
            Some(&request_values),
        )
        .expect("audit insert values should resolve");

        assert_eq!(
            values,
            vec![
                ColumnValue::new("name", SqlValue::String("existing".to_string())),
                ColumnValue::new("created_by", SqlValue::I64(7)),
                ColumnValue::new("updated_by", SqlValue::String("provider".to_string())),
            ]
        );
    }

    #[test]
    fn apply_audit_values_rejects_duplicate_insert_columns() {
        let error = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Insert,
            vec![
                ColumnValue::new("created_by", SqlValue::I64(7)),
                ColumnValue::new("created_by", SqlValue::I64(8)),
            ],
            None,
            None,
        )
        .unwrap_err();

        assert_eq!(
            error,
            OrmError::new("duplicate column `created_by` in audit values")
        );
    }

    #[test]
    fn apply_audit_values_rejects_non_insertable_audit_column() {
        let request_values = AuditRequestValues::new(vec![ColumnValue::new(
            "created_at",
            SqlValue::String("runtime".to_string()),
        )]);

        let error = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Insert,
            Vec::new(),
            None,
            Some(&request_values),
        )
        .unwrap_err();

        assert_eq!(
            error,
            OrmError::new("audit insert column `created_at` is not insertable")
        );
    }

    #[test]
    fn apply_audit_values_rejects_null_for_non_nullable_audit_column() {
        let request_values =
            AuditRequestValues::new(vec![ColumnValue::new("created_by", SqlValue::Null)]);

        let error = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Insert,
            Vec::new(),
            None,
            Some(&request_values),
        )
        .unwrap_err();

        assert_eq!(
            error,
            OrmError::new("audit column `created_by` is not nullable")
        );
    }

    #[test]
    fn apply_audit_values_completes_only_missing_updatable_audit_columns() {
        struct Provider;

        impl AuditProvider for Provider {
            fn values(&self, _context: AuditContext<'_>) -> Result<Vec<ColumnValue>, OrmError> {
                Ok(vec![
                    ColumnValue::new("created_by", SqlValue::I64(9)),
                    ColumnValue::new("updated_by", SqlValue::String("provider".to_string())),
                ])
            }
        }

        let values = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Update,
            vec![
                ColumnValue::new("name", SqlValue::String("updated".to_string())),
                ColumnValue::new("updated_by", SqlValue::String("explicit".to_string())),
            ],
            Some(&Provider),
            None,
        )
        .expect("audit update values should resolve");

        assert_eq!(
            values,
            vec![
                ColumnValue::new("name", SqlValue::String("updated".to_string())),
                ColumnValue::new("updated_by", SqlValue::String("explicit".to_string())),
                ColumnValue::new("created_by", SqlValue::I64(9)),
            ]
        );
    }

    #[test]
    fn apply_audit_values_rejects_non_updatable_audit_column() {
        let error = apply_audit_values::<TestAuditedEntity>(
            AuditOperation::Update,
            vec![ColumnValue::new(
                "created_at",
                SqlValue::String("runtime".to_string()),
            )],
            None,
            None,
        )
        .unwrap_err();

        assert_eq!(
            error,
            OrmError::new("audit update column `created_at` is not updatable")
        );
    }

    #[test]
    fn resolve_audit_values_preserves_user_values_before_request_and_provider_values() {
        let request_values = AuditRequestValues::new(vec![
            ColumnValue::new(
                "created_at",
                SqlValue::String("request-created-at".to_string()),
            ),
            ColumnValue::new(
                "created_by",
                SqlValue::String("request-created-by".to_string()),
            ),
        ]);

        let resolved = resolve_audit_values(
            vec![ColumnValue::new(
                "created_at",
                SqlValue::String("user-created-at".to_string()),
            )],
            context(Some(&request_values)),
            Some(&FixedAuditProvider),
        )
        .expect("audit values should resolve");

        assert_eq!(
            resolved,
            vec![
                ColumnValue::new(
                    "created_at",
                    SqlValue::String("user-created-at".to_string())
                ),
                ColumnValue::new(
                    "created_by",
                    SqlValue::String("request-created-by".to_string())
                ),
                ColumnValue::new(
                    "updated_by",
                    SqlValue::String("provider-updated-by".to_string())
                ),
            ]
        );
    }

    #[test]
    fn resolve_audit_values_uses_request_values_without_provider() {
        let request_values = AuditRequestValues::new(vec![ColumnValue::new(
            "updated_by",
            SqlValue::String("request-updated-by".to_string()),
        )]);

        let resolved = resolve_audit_values(vec![], context(Some(&request_values)), None)
            .expect("request audit values should resolve");

        assert_eq!(
            resolved,
            vec![ColumnValue::new(
                "updated_by",
                SqlValue::String("request-updated-by".to_string())
            )]
        );
    }

    #[test]
    fn resolve_audit_values_rejects_duplicate_user_columns() {
        let error = resolve_audit_values(
            vec![
                ColumnValue::new("created_at", SqlValue::String("first".to_string())),
                ColumnValue::new("created_at", SqlValue::String("second".to_string())),
            ],
            context(None),
            None,
        )
        .unwrap_err();

        assert_eq!(
            error,
            OrmError::new("duplicate column `created_at` in audit values")
        );
    }

    #[test]
    fn resolve_audit_values_rejects_duplicate_request_columns() {
        let request_values = AuditRequestValues::new(vec![
            ColumnValue::new("created_by", SqlValue::String("first".to_string())),
            ColumnValue::new("created_by", SqlValue::String("second".to_string())),
        ]);

        let error = resolve_audit_values(vec![], context(Some(&request_values)), None).unwrap_err();

        assert_eq!(
            error,
            OrmError::new("duplicate column `created_by` in audit request values")
        );
    }

    #[test]
    fn resolve_audit_values_rejects_duplicate_provider_columns() {
        struct DuplicateProvider;

        impl AuditProvider for DuplicateProvider {
            fn values(&self, _context: AuditContext<'_>) -> Result<Vec<ColumnValue>, OrmError> {
                Ok(vec![
                    ColumnValue::new("updated_at", SqlValue::String("first".to_string())),
                    ColumnValue::new("updated_at", SqlValue::String("second".to_string())),
                ])
            }
        }

        let error =
            resolve_audit_values(vec![], context(None), Some(&DuplicateProvider)).unwrap_err();

        assert_eq!(
            error,
            OrmError::new("duplicate column `updated_at` in audit provider values")
        );
    }
}