hermes_core/dsl/sdl/

mod.rs

//! Schema Definition Language (SDL) for Hermes
//!
//! A simple, readable format for defining index schemas using pest parser.
//!
//! # Example SDL
//!
//! ```text
//! # Article index schema
//! index articles {
//!     # Primary text field for full-text search
//!     field title: text [indexed, stored]
//!     
//!     # Body content - indexed but not stored (save space)
//!     field body: text [indexed]
//!     
//!     # Author name
//!     field author: text [indexed, stored]
//!     
//!     # Publication timestamp
//!     field published_at: i64 [indexed, stored]
//!     
//!     # View count
//!     field views: u64 [indexed, stored]
//!     
//!     # Rating score
//!     field rating: f64 [indexed, stored]
//!     
//!     # Raw content hash (not indexed, just stored)
//!     field content_hash: bytes [stored]
//! }
//! ```

use pest::Parser;
use pest_derive::Parser;

use super::query_field_router::{QueryRouterRule, RoutingMode};
use super::schema::{FieldType, Schema, SchemaBuilder};
use crate::Result;
use crate::error::Error;

#[derive(Parser)]
#[grammar = "dsl/sdl/sdl.pest"]
pub struct SdlParser;

/// Parsed field definition
#[derive(Debug, Clone)]
pub struct FieldDef {
    pub name: String,
    pub field_type: FieldType,
    pub indexed: bool,
    pub stored: bool,
    /// Tokenizer name for text fields (e.g., "default", "en_stem", "german")
    pub tokenizer: Option<String>,
    /// Whether this field can have multiple values (serialized as array in JSON)
    pub multi: bool,
}

/// Parsed index definition
#[derive(Debug, Clone)]
pub struct IndexDef {
    pub name: String,
    pub fields: Vec<FieldDef>,
    pub default_fields: Vec<String>,
    /// Query router rules for routing queries to specific fields
    pub query_routers: Vec<QueryRouterRule>,
}

impl IndexDef {
    /// Convert to a Schema
    pub fn to_schema(&self) -> Schema {
        let mut builder = SchemaBuilder::default();

        for field in &self.fields {
            let f = match field.field_type {
                FieldType::Text => {
                    let tokenizer = field.tokenizer.as_deref().unwrap_or("default");
                    builder.add_text_field_with_tokenizer(
                        &field.name,
                        field.indexed,
                        field.stored,
                        tokenizer,
                    )
                }
                FieldType::U64 => {
                    builder.add_u64_field(&field.name, field.indexed, field.stored)
                }
                FieldType::I64 => {
                    builder.add_i64_field(&field.name, field.indexed, field.stored)
                }
                FieldType::F64 => {
                    builder.add_f64_field(&field.name, field.indexed, field.stored)
                }
                FieldType::Bytes => builder.add_bytes_field(&field.name, field.stored),
            };
            if field.multi {
                builder.set_multi(f, true);
            }
        }

        // Set default fields if specified
        if !self.default_fields.is_empty() {
            builder.set_default_fields(self.default_fields.clone());
        }

        // Set query routers if specified
        if !self.query_routers.is_empty() {
            builder.set_query_routers(self.query_routers.clone());
        }

        builder.build()
    }

    /// Create a QueryFieldRouter from the query router rules
    ///
    /// Returns None if there are no query router rules defined.
    /// Returns Err if any regex pattern is invalid.
    pub fn to_query_router(
        &self,
    ) -> Result<Option<super::query_field_router::QueryFieldRouter>> {
        if self.query_routers.is_empty() {
            return Ok(None);
        }

        super::query_field_router::QueryFieldRouter::from_rules(&self.query_routers)
            .map(Some)
            .map_err(|e| Error::Schema(e))
    }
}

/// Parse field type from string
fn parse_field_type(type_str: &str) -> Result<FieldType> {
    match type_str {
        "text" | "string" | "str" => Ok(FieldType::Text),
        "u64" | "uint" | "unsigned" => Ok(FieldType::U64),
        "i64" | "int" | "integer" => Ok(FieldType::I64),
        "f64" | "float" | "double" => Ok(FieldType::F64),
        "bytes" | "binary" | "blob" => Ok(FieldType::Bytes),
        _ => Err(Error::Schema(format!("Unknown field type: {}", type_str))),
    }
}

/// Parse attributes from pest pair
/// Returns (indexed, stored, multi)
fn parse_attributes(pair: pest::iterators::Pair<Rule>) -> (bool, bool, bool) {
    let mut indexed = false;
    let mut stored = false;
    let mut multi = false;

    for attr in pair.into_inner() {
        match attr.as_str() {
            "indexed" => indexed = true,
            "stored" => stored = true,
            "multi" => multi = true,
            _ => {}
        }
    }

    (indexed, stored, multi)
}

/// Parse a field definition from pest pair
fn parse_field_def(pair: pest::iterators::Pair<Rule>) -> Result<FieldDef> {
    let mut inner = pair.into_inner();

    let name = inner
        .next()
        .ok_or_else(|| Error::Schema("Missing field name".to_string()))?
        .as_str()
        .to_string();

    let field_type_str = inner
        .next()
        .ok_or_else(|| Error::Schema("Missing field type".to_string()))?
        .as_str();

    let field_type = parse_field_type(field_type_str)?;

    // Parse optional tokenizer spec and attributes
    let mut tokenizer = None;
    let mut indexed = true;
    let mut stored = true;
    let mut multi = false;

    for item in inner {
        match item.as_rule() {
            Rule::tokenizer_spec => {
                // Extract tokenizer name from <name>
                if let Some(tok_name) = item.into_inner().next() {
                    tokenizer = Some(tok_name.as_str().to_string());
                }
            }
            Rule::attributes => {
                let (idx, sto, mul) = parse_attributes(item);
                indexed = idx;
                stored = sto;
                multi = mul;
            }
            _ => {}
        }
    }

    Ok(FieldDef {
        name,
        field_type,
        indexed,
        stored,
        tokenizer,
        multi,
    })
}

/// Parse default_fields definition
fn parse_default_fields_def(pair: pest::iterators::Pair<Rule>) -> Vec<String> {
    pair.into_inner().map(|p| p.as_str().to_string()).collect()
}

/// Parse a query router definition
fn parse_query_router_def(pair: pest::iterators::Pair<Rule>) -> Result<QueryRouterRule> {
    let mut pattern = String::new();
    let mut substitution = String::new();
    let mut target_field = String::new();
    let mut mode = RoutingMode::Additional;

    for prop in pair.into_inner() {
        if prop.as_rule() != Rule::query_router_prop {
            continue;
        }

        for inner in prop.into_inner() {
            match inner.as_rule() {
                Rule::query_router_pattern => {
                    if let Some(regex_str) = inner.into_inner().next() {
                        pattern = parse_string_value(regex_str);
                    }
                }
                Rule::query_router_substitution => {
                    if let Some(quoted) = inner.into_inner().next() {
                        substitution = parse_string_value(quoted);
                    }
                }
                Rule::query_router_target => {
                    if let Some(ident) = inner.into_inner().next() {
                        target_field = ident.as_str().to_string();
                    }
                }
                Rule::query_router_mode => {
                    if let Some(mode_val) = inner.into_inner().next() {
                        mode = match mode_val.as_str() {
                            "exclusive" => RoutingMode::Exclusive,
                            "additional" => RoutingMode::Additional,
                            _ => RoutingMode::Additional,
                        };
                    }
                }
                _ => {}
            }
        }
    }

    if pattern.is_empty() {
        return Err(Error::Schema("query_router missing 'pattern'".to_string()));
    }
    if substitution.is_empty() {
        return Err(Error::Schema(
            "query_router missing 'substitution'".to_string(),
        ));
    }
    if target_field.is_empty() {
        return Err(Error::Schema(
            "query_router missing 'target_field'".to_string(),
        ));
    }

    Ok(QueryRouterRule {
        pattern,
        substitution,
        target_field,
        mode,
    })
}

/// Parse a string value from quoted_string, raw_string, or regex_string
fn parse_string_value(pair: pest::iterators::Pair<Rule>) -> String {
    let s = pair.as_str();
    match pair.as_rule() {
        Rule::regex_string => {
            // regex_string contains either raw_string or quoted_string
            if let Some(inner) = pair.into_inner().next() {
                parse_string_value(inner)
            } else {
                s.to_string()
            }
        }
        Rule::raw_string => {
            // r"..." - strip r" prefix and " suffix
            s[2..s.len() - 1].to_string()
        }
        Rule::quoted_string => {
            // "..." - strip quotes and handle escapes
            let inner = &s[1..s.len() - 1];
            // Simple escape handling
            inner
                .replace("\\n", "\n")
                .replace("\\t", "\t")
                .replace("\\\"", "\"")
                .replace("\\\\", "\\")
        }
        _ => s.to_string(),
    }
}

/// Parse an index definition from pest pair
fn parse_index_def(pair: pest::iterators::Pair<Rule>) -> Result<IndexDef> {
    let mut inner = pair.into_inner();

    let name = inner
        .next()
        .ok_or_else(|| Error::Schema("Missing index name".to_string()))?
        .as_str()
        .to_string();

    let mut fields = Vec::new();
    let mut default_fields = Vec::new();
    let mut query_routers = Vec::new();

    for item in inner {
        match item.as_rule() {
            Rule::field_def => {
                fields.push(parse_field_def(item)?);
            }
            Rule::default_fields_def => {
                default_fields = parse_default_fields_def(item);
            }
            Rule::query_router_def => {
                query_routers.push(parse_query_router_def(item)?);
            }
            _ => {}
        }
    }

    Ok(IndexDef {
        name,
        fields,
        default_fields,
        query_routers,
    })
}

/// Parse SDL from a string
pub fn parse_sdl(input: &str) -> Result<Vec<IndexDef>> {
    let pairs = SdlParser::parse(Rule::file, input)
        .map_err(|e| Error::Schema(format!("Parse error: {}", e)))?;

    let mut indexes = Vec::new();

    for pair in pairs {
        if pair.as_rule() == Rule::file {
            for inner in pair.into_inner() {
                if inner.as_rule() == Rule::index_def {
                    indexes.push(parse_index_def(inner)?);
                }
            }
        }
    }

    Ok(indexes)
}

/// Parse SDL and return a single index definition
pub fn parse_single_index(input: &str) -> Result<IndexDef> {
    let indexes = parse_sdl(input)?;

    if indexes.is_empty() {
        return Err(Error::Schema("No index definition found".to_string()));
    }

    if indexes.len() > 1 {
        return Err(Error::Schema(
            "Multiple index definitions found, expected one".to_string(),
        ));
    }

    Ok(indexes.into_iter().next().unwrap())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_parse_simple_schema() {
        let sdl = r#"
            index articles {
                field title: text [indexed, stored]
                field body: text [indexed]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        assert_eq!(indexes.len(), 1);

        let index = &indexes[0];
        assert_eq!(index.name, "articles");
        assert_eq!(index.fields.len(), 2);

        assert_eq!(index.fields[0].name, "title");
        assert!(matches!(index.fields[0].field_type, FieldType::Text));
        assert!(index.fields[0].indexed);
        assert!(index.fields[0].stored);

        assert_eq!(index.fields[1].name, "body");
        assert!(matches!(index.fields[1].field_type, FieldType::Text));
        assert!(index.fields[1].indexed);
        assert!(!index.fields[1].stored);
    }

    #[test]
    fn test_parse_all_field_types() {
        let sdl = r#"
            index test {
                field text_field: text [indexed, stored]
                field u64_field: u64 [indexed, stored]
                field i64_field: i64 [indexed, stored]
                field f64_field: f64 [indexed, stored]
                field bytes_field: bytes [stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let index = &indexes[0];

        assert!(matches!(index.fields[0].field_type, FieldType::Text));
        assert!(matches!(index.fields[1].field_type, FieldType::U64));
        assert!(matches!(index.fields[2].field_type, FieldType::I64));
        assert!(matches!(index.fields[3].field_type, FieldType::F64));
        assert!(matches!(index.fields[4].field_type, FieldType::Bytes));
    }

    #[test]
    fn test_parse_with_comments() {
        let sdl = r#"
            # This is a comment
            index articles {
                # Title field
                field title: text [indexed, stored]
                field body: text [indexed] # inline comment not supported yet
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        assert_eq!(indexes[0].fields.len(), 2);
    }

    #[test]
    fn test_parse_type_aliases() {
        let sdl = r#"
            index test {
                field a: string [indexed]
                field b: int [indexed]
                field c: uint [indexed]
                field d: float [indexed]
                field e: binary [stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let index = &indexes[0];

        assert!(matches!(index.fields[0].field_type, FieldType::Text));
        assert!(matches!(index.fields[1].field_type, FieldType::I64));
        assert!(matches!(index.fields[2].field_type, FieldType::U64));
        assert!(matches!(index.fields[3].field_type, FieldType::F64));
        assert!(matches!(index.fields[4].field_type, FieldType::Bytes));
    }

    #[test]
    fn test_to_schema() {
        let sdl = r#"
            index articles {
                field title: text [indexed, stored]
                field views: u64 [indexed, stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let schema = indexes[0].to_schema();

        assert!(schema.get_field("title").is_some());
        assert!(schema.get_field("views").is_some());
        assert!(schema.get_field("nonexistent").is_none());
    }

    #[test]
    fn test_default_attributes() {
        let sdl = r#"
            index test {
                field title: text
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let field = &indexes[0].fields[0];

        // Default should be indexed and stored
        assert!(field.indexed);
        assert!(field.stored);
    }

    #[test]
    fn test_multiple_indexes() {
        let sdl = r#"
            index articles {
                field title: text [indexed, stored]
            }
            
            index users {
                field name: text [indexed, stored]
                field email: text [indexed, stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        assert_eq!(indexes.len(), 2);
        assert_eq!(indexes[0].name, "articles");
        assert_eq!(indexes[1].name, "users");
    }

    #[test]
    fn test_tokenizer_spec() {
        let sdl = r#"
            index articles {
                field title: text<en_stem> [indexed, stored]
                field body: text<default> [indexed]
                field author: text [indexed, stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let index = &indexes[0];

        assert_eq!(index.fields[0].name, "title");
        assert_eq!(index.fields[0].tokenizer, Some("en_stem".to_string()));

        assert_eq!(index.fields[1].name, "body");
        assert_eq!(index.fields[1].tokenizer, Some("default".to_string()));

        assert_eq!(index.fields[2].name, "author");
        assert_eq!(index.fields[2].tokenizer, None); // No tokenizer specified
    }

    #[test]
    fn test_tokenizer_in_schema() {
        let sdl = r#"
            index articles {
                field title: text<german> [indexed, stored]
                field body: text<en_stem> [indexed]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let schema = indexes[0].to_schema();

        let title_field = schema.get_field("title").unwrap();
        let title_entry = schema.get_field_entry(title_field).unwrap();
        assert_eq!(title_entry.tokenizer, Some("german".to_string()));

        let body_field = schema.get_field("body").unwrap();
        let body_entry = schema.get_field_entry(body_field).unwrap();
        assert_eq!(body_entry.tokenizer, Some("en_stem".to_string()));
    }

    #[test]
    fn test_query_router_basic() {
        let sdl = r#"
            index documents {
                field title: text [indexed, stored]
                field uri: text [indexed, stored]
                
                query_router {
                    pattern: "10\\.\\d{4,}/[^\\s]+"
                    substitution: "doi://{0}"
                    target_field: uris
                    mode: exclusive
                }
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let index = &indexes[0];

        assert_eq!(index.query_routers.len(), 1);
        let router = &index.query_routers[0];
        assert_eq!(router.pattern, r"10\.\d{4,}/[^\s]+");
        assert_eq!(router.substitution, "doi://{0}");
        assert_eq!(router.target_field, "uris");
        assert_eq!(router.mode, RoutingMode::Exclusive);
    }

    #[test]
    fn test_query_router_raw_string() {
        let sdl = r#"
            index documents {
                field uris: text [indexed, stored]
                
                query_router {
                    pattern: r"^pmid:(\d+)$"
                    substitution: "pubmed://{1}"
                    target_field: uris
                    mode: additional
                }
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        let router = &indexes[0].query_routers[0];

        assert_eq!(router.pattern, r"^pmid:(\d+)$");
        assert_eq!(router.substitution, "pubmed://{1}");
        assert_eq!(router.mode, RoutingMode::Additional);
    }

    #[test]
    fn test_multiple_query_routers() {
        let sdl = r#"
            index documents {
                field uris: text [indexed, stored]
                
                query_router {
                    pattern: r"^doi:(10\.\d{4,}/[^\s]+)$"
                    substitution: "doi://{1}"
                    target_field: uris
                    mode: exclusive
                }
                
                query_router {
                    pattern: r"^pmid:(\d+)$"
                    substitution: "pubmed://{1}"
                    target_field: uris
                    mode: exclusive
                }
                
                query_router {
                    pattern: r"^arxiv:(\d+\.\d+)$"
                    substitution: "arxiv://{1}"
                    target_field: uris
                    mode: additional
                }
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        assert_eq!(indexes[0].query_routers.len(), 3);
    }

    #[test]
    fn test_query_router_default_mode() {
        let sdl = r#"
            index documents {
                field uris: text [indexed, stored]
                
                query_router {
                    pattern: r"test"
                    substitution: "{0}"
                    target_field: uris
                }
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        // Default mode should be Additional
        assert_eq!(indexes[0].query_routers[0].mode, RoutingMode::Additional);
    }

    #[test]
    fn test_multi_attribute() {
        let sdl = r#"
            index documents {
                field uris: text [indexed, stored, multi]
                field title: text [indexed, stored]
            }
        "#;

        let indexes = parse_sdl(sdl).unwrap();
        assert_eq!(indexes.len(), 1);
        
        let fields = &indexes[0].fields;
        assert_eq!(fields.len(), 2);
        
        // uris should have multi=true
        assert_eq!(fields[0].name, "uris");
        assert!(fields[0].multi, "uris field should have multi=true");
        
        // title should have multi=false
        assert_eq!(fields[1].name, "title");
        assert!(!fields[1].multi, "title field should have multi=false");

        // Verify schema conversion preserves multi attribute
        let schema = indexes[0].to_schema();
        let uris_field = schema.get_field("uris").unwrap();
        let title_field = schema.get_field("title").unwrap();
        
        assert!(schema.get_field_entry(uris_field).unwrap().multi);
        assert!(!schema.get_field_entry(title_field).unwrap().multi);
    }
}