scythe-codegen 0.19.0

use std::fmt::Write;

use scythe_backend::manifest::BackendManifest;
use scythe_backend::naming::{composite_type_name, enum_type_name, enum_variant_name, fn_name};

use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
use scythe_core::errors::{ErrorCode, ScytheError};
use scythe_core::parser::QueryCommand;

use crate::backend_trait::{CodegenBackend, GroupedQueryFn, RbsGenerationContext, ResolvedColumn, ResolvedParam};

const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/ruby-tiny-tds.toml");

/// Check if a neutral type should not be escaped (numeric or boolean types).
/// Neutral types are core type identifiers like "int32", "bool", "decimal".
fn is_numeric_or_bool_type(neutral_type: &str) -> bool {
    let base_type = if neutral_type.contains('<') {
        neutral_type.split('<').next().unwrap_or("")
    } else {
        neutral_type
    };

    matches!(
        base_type,
        "bool" | "int16" | "int32" | "int64" | "float32" | "float64" | "decimal"
    )
}

/// Check if a neutral type is specifically a boolean.
fn is_bool_type(neutral_type: &str) -> bool {
    let base_type = if neutral_type.contains('<') {
        neutral_type.split('<').next().unwrap_or("")
    } else {
        neutral_type
    };
    base_type == "bool"
}

/// Generate the inline SQL interpolation for a parameter value.
/// Returns the string that replaces `@pN` directly in the SQL body.
/// - Booleans: `#{var ? 1 : 0}`
/// - Other numeric/decimal types: `#{var}`
/// - Nullable strings: `#{var.nil? ? 'NULL' : "'#{client.escape(var)}'"}`
/// - Non-nullable strings: `'#{client.escape(var)}'`
/// - `var_access` is used to reference the variable (e.g., "id" or "item[:id]")
fn generate_inline_value(neutral_type: &str, var_access: &str, nullable: bool) -> String {
    if is_bool_type(neutral_type) {
        format!("#{{{} ? 1 : 0}}", var_access)
    } else if is_numeric_or_bool_type(neutral_type) {
        format!("#{{{}}}", var_access)
    } else if nullable {
        format!(
            "#{{ {}.nil? ? 'NULL' : \"'#{{client.escape({})}}'\"}}",
            var_access, var_access
        )
    } else {
        format!("'#{{client.escape({})}}'", var_access)
    }
}

/// Replace `@p1`, `@p2`, ... placeholders in the SQL string with inline Ruby interpolations.
fn inline_params(sql: &str, params: &[(String, String, bool)]) -> String {
    let mut result = sql.to_string();
    for (index, (neutral_type, var_access, nullable)) in params.iter().enumerate().rev() {
        let placeholder = format!("@p{}", index + 1);
        let value = generate_inline_value(neutral_type, var_access, *nullable);
        result = result.replace(&placeholder, &value);
    }
    result
}

pub struct RubyTinyTdsBackend {
    manifest: BackendManifest,
}

impl RubyTinyTdsBackend {
    pub fn new(engine: &str) -> Result<Self, ScytheError> {
        match engine {
            "mssql" => {}
            _ => {
                return Err(ScytheError::new(
                    ErrorCode::InvalidConfig,
                    format!("ruby-tiny-tds only supports MSSQL, got engine '{}'", engine),
                ));
            }
        }
        let manifest = super::parse_manifest(DEFAULT_MANIFEST_TOML)?;
        Ok(Self { manifest })
    }
}

/// Rewrite $1, $2, ... to @p1, @p2, ... for MSSQL.
impl CodegenBackend for RubyTinyTdsBackend {
    fn name(&self) -> &str {
        "ruby-tiny-tds"
    }

    fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
        &self.manifest
    }

    fn manifest_mut(&mut self) -> &mut scythe_backend::manifest::BackendManifest {
        &mut self.manifest
    }

    fn supported_engines(&self) -> &[&str] {
        &["mssql"]
    }

    fn generate_rbs_file(&self, context: &RbsGenerationContext) -> Option<String> {
        Some(super::ruby_rbs::generate_rbs_content(
            context,
            "TinyTds::Client",
            &self.manifest,
        ))
    }

    fn file_preamble(&self) -> String {
        "# frozen_string_literal: true\n".to_string()
    }

    fn file_header(&self) -> String {
        format!(
            "require \"tiny_tds\"\n\nmodule Queries\n{}",
            super::ruby_rbs::RECORD_NOT_FOUND_CLASS
        )
    }

    fn file_footer(&self) -> String {
        "end".to_string()
    }

    fn generate_struct_decl(
        &self,
        struct_name: &str,
        _query_name: &str,
        columns: &[ResolvedColumn],
    ) -> Result<String, ScytheError> {
        let fields = columns
            .iter()
            .map(|c| format!(":{}", c.field_name))
            .collect::<Vec<_>>()
            .join(", ");
        let mut out = String::new();
        let _ = writeln!(out, "  {} = Data.define({})", struct_name, fields);
        Ok(out)
    }

    fn generate_query_fn(
        &self,
        analyzed: &AnalyzedQuery,
        struct_name: &str,
        columns: &[ResolvedColumn],
        params: &[ResolvedParam],
    ) -> Result<String, ScytheError> {
        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
        let sql = crate::sql_literal::escape_ruby_double_quoted(&super::rewrite_pg_placeholders(
            &super::clean_sql_with_optional(&analyzed.sql, &analyzed.optional_params, &analyzed.params),
            |n| format!("@p{n}"),
        ));
        let mut out = String::new();

        let param_list = params
            .iter()
            .map(|p| p.field_name.clone())
            .collect::<Vec<_>>()
            .join(", ");
        let sep = if param_list.is_empty() { "" } else { ", " };

        // WARNING: TinyTDS does not support native parameterized queries.
        if !matches!(analyzed.command, QueryCommand::Batch) {
            let _ = writeln!(out, "  def self.{}(client{}{})", func_name, sep, param_list);
        }

        match &analyzed.command {
            QueryCommand::One => {
                if params.is_empty() {
                    let _ = writeln!(out, "    result = client.execute(\"{}\").first", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| (p.neutral_type.clone(), p.field_name.clone(), p.nullable))
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "    sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "    result = client.execute(sql).first");
                }
                let _ = writeln!(
                    out,
                    "    raise RecordNotFound, \"{}: no row found\" if result.nil?",
                    func_name
                );

                let fields = columns
                    .iter()
                    .map(|c| format!("{}: result[\"{}\"]", c.field_name, c.name))
                    .collect::<Vec<_>>()
                    .join(", ");
                let _ = writeln!(out, "    {}.new({})", struct_name, fields);
            }
            QueryCommand::Opt => {
                if params.is_empty() {
                    let _ = writeln!(out, "    result = client.execute(\"{}\").first", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| (p.neutral_type.clone(), p.field_name.clone(), p.nullable))
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "    sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "    result = client.execute(sql).first");
                }
                let _ = writeln!(out, "    return nil if result.nil?");

                let fields = columns
                    .iter()
                    .map(|c| format!("{}: result[\"{}\"]", c.field_name, c.name))
                    .collect::<Vec<_>>()
                    .join(", ");
                let _ = writeln!(out, "    {}.new({})", struct_name, fields);
            }
            QueryCommand::Batch => {
                let batch_fn_name = format!("{}_batch", func_name);
                let _ = writeln!(out, "  def self.{}(client, items)", batch_fn_name);
                let _ = writeln!(out, "    items.each do |item|");
                if params.is_empty() {
                    let _ = writeln!(out, "      client.execute(\"{}\").do", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| {
                            let var_access = if params.len() == 1 {
                                "item".to_string()
                            } else {
                                format!("item[:{}]", p.field_name)
                            };
                            (p.neutral_type.clone(), var_access, p.nullable)
                        })
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "      sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "      client.execute(sql).do");
                }
                let _ = writeln!(out, "    end");
                let _ = write!(out, "  end");
                return Ok(out);
            }
            QueryCommand::Many => {
                if params.is_empty() {
                    let _ = writeln!(out, "    results = client.execute(\"{}\")", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| (p.neutral_type.clone(), p.field_name.clone(), p.nullable))
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "    sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "    results = client.execute(sql)");
                }
                let _ = writeln!(out, "    results.map do |row|");
                let fields = columns
                    .iter()
                    .map(|c| format!("{}: row[\"{}\"]", c.field_name, c.name))
                    .collect::<Vec<_>>()
                    .join(", ");
                let _ = writeln!(out, "      {}.new({})", struct_name, fields);
                let _ = writeln!(out, "    end");
            }
            QueryCommand::Exec => {
                if params.is_empty() {
                    let _ = writeln!(out, "    client.execute(\"{}\").do", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| (p.neutral_type.clone(), p.field_name.clone(), p.nullable))
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "    sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "    client.execute(sql).do");
                }
                let _ = writeln!(out, "    nil");
            }
            QueryCommand::ExecResult | QueryCommand::ExecRows => {
                if params.is_empty() {
                    let _ = writeln!(out, "    client.execute(\"{}\").affected_rows", sql);
                } else {
                    let params_info: Vec<(String, String, bool)> = params
                        .iter()
                        .map(|p| (p.neutral_type.clone(), p.field_name.clone(), p.nullable))
                        .collect();
                    let inlined_sql = inline_params(&sql, &params_info);
                    let _ = writeln!(out, "    sql = \"{}\"", inlined_sql);
                    let _ = writeln!(out, "    client.execute(sql).affected_rows");
                }
            }
            QueryCommand::Grouped => unreachable!("handled by generate_grouped_query_fn"),
        }

        let _ = write!(out, "  end");
        Ok(out)
    }

    fn generate_grouped_structs(
        &self,
        parent_struct_name: &str,
        child_struct_name: &str,
        parent_columns: &[ResolvedColumn],
        child_columns: &[ResolvedColumn],
        _key_column: &str,
    ) -> Result<String, ScytheError> {
        Ok(super::ruby_rbs::generate_grouped_structs_ruby(
            parent_struct_name,
            child_struct_name,
            parent_columns,
            child_columns,
        ))
    }

    fn generate_grouped_query_fn(&self, request: &GroupedQueryFn<'_>) -> Result<String, ScytheError> {
        let analyzed = request.analyzed;
        let parent_struct_name = request.parent_struct_name;
        let child_struct_name = request.child_struct_name;
        let parent_columns = request.parent_columns;
        let child_columns = request.child_columns;
        let params = request.params;
        let key_column = request.key_column;

        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
        let sql = crate::sql_literal::escape_ruby_double_quoted(&super::clean_sql_with_optional(
            &analyzed.sql,
            &analyzed.optional_params,
            &analyzed.params,
        ));

        let param_list = params
            .iter()
            .map(|p| p.field_name.clone())
            .collect::<Vec<_>>()
            .join(", ");
        let sep = if param_list.is_empty() { "" } else { ", " };

        let sql_with_placeholders = {
            let mut s = sql.clone();
            let mut n = 1u32;
            while let Some(pos) = s.find('$') {
                let end = s[pos + 1..]
                    .find(|c: char| !c.is_ascii_digit())
                    .map_or(s.len(), |i| pos + 1 + i);
                s.replace_range(pos..end, &format!("@p{n}"));
                n += 1;
            }
            s
        };

        let final_sql = if params.is_empty() {
            sql_with_placeholders.clone()
        } else {
            sql_with_placeholders
        };

        let mut out = String::new();
        let _ = writeln!(out, "  def self.{}(client{}{})", func_name, sep, param_list);
        if params.is_empty() {
            let _ = writeln!(out, "    results = client.execute(\"{}\")", final_sql);
        } else {
            let _ = writeln!(out, "    sql = \"{}\"", final_sql);
            let params_hash = params
                .iter()
                .enumerate()
                .map(|(i, p)| format!("\"@p{}\": {}", i + 1, p.field_name))
                .collect::<Vec<_>>()
                .join(", ");
            let _ = writeln!(out, "    results = client.execute(sql, {{{}}})", params_hash);
        }
        let _ = writeln!(out, "    _index = {{}}");
        let _ = writeln!(out, "    _entries = []");
        let _ = writeln!(out, "    results.each do |row|");
        let _ = writeln!(out, "      key = row[\"{}\"]", key_column);
        let _ = writeln!(out, "      unless _index.key?(key)");
        let _ = writeln!(out, "        _index[key] = _entries.size");
        let _ = writeln!(out, "        _entries << {{");
        for col in parent_columns {
            let _ = writeln!(out, "          {}: row[\"{}\"],", col.field_name, col.name);
        }
        let _ = writeln!(out, "          children: []");
        let _ = writeln!(out, "        }}");
        let _ = writeln!(out, "      end");
        let _ = writeln!(
            out,
            "      _entries[_index[key]][:children] << {}.new(",
            child_struct_name
        );
        for col in child_columns {
            let _ = writeln!(out, "        {}: row[\"{}\"],", col.field_name, col.name);
        }
        let _ = writeln!(out, "      )");
        let _ = writeln!(out, "    end");
        let _ = writeln!(out, "    _entries.map {{ |e| {}.new(**e) }}", parent_struct_name);
        let _ = write!(out, "  end");

        Ok(out)
    }

    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
        let mut out = String::new();
        let _ = writeln!(out, "  module {}", type_name);
        for value in &enum_info.values {
            let variant = enum_variant_name(value, &self.manifest.naming);
            let _ = writeln!(out, "    {} = \"{}\"", variant, value);
        }
        let all_values = enum_info
            .values
            .iter()
            .map(|v| enum_variant_name(v, &self.manifest.naming))
            .collect::<Vec<_>>()
            .join(", ");
        let _ = writeln!(out, "    ALL = [{}].freeze", all_values);
        let _ = write!(out, "  end");
        Ok(out)
    }

    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
        let name = composite_type_name(&composite.sql_name, &self.manifest.naming);
        let mut out = String::new();
        if composite.fields.is_empty() {
            let _ = writeln!(out, "  {} = Data.define()", name);
        } else {
            let fields = composite
                .fields
                .iter()
                .map(|f| format!(":{}", f.name))
                .collect::<Vec<_>>()
                .join(", ");
            let _ = writeln!(out, "  {} = Data.define({})", name, fields);
        }
        Ok(out)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use scythe_core::analyzer::{AnalyzedColumn, AnalyzedQuery, GroupByConfig};
    use scythe_core::parser::QueryCommand;

    fn make_grouped_query() -> AnalyzedQuery {
        let parent_cols = vec![
            AnalyzedColumn {
                name: "id".to_string(),
                neutral_type: "int32".to_string(),
                nullable: false,
                ..Default::default()
            },
            AnalyzedColumn {
                name: "name".to_string(),
                neutral_type: "string".to_string(),
                nullable: false,
                ..Default::default()
            },
            AnalyzedColumn {
                name: "email".to_string(),
                neutral_type: "string".to_string(),
                nullable: false,
                ..Default::default()
            },
        ];
        let child_cols = vec![
            AnalyzedColumn {
                name: "order_id".to_string(),
                neutral_type: "int32".to_string(),
                nullable: false,
                ..Default::default()
            },
            AnalyzedColumn {
                name: "total".to_string(),
                neutral_type: "decimal".to_string(),
                nullable: true,
                ..Default::default()
            },
            AnalyzedColumn {
                name: "order_date".to_string(),
                neutral_type: "datetime".to_string(),
                nullable: false,
                ..Default::default()
            },
        ];
        let all_cols = [parent_cols.clone(), child_cols.clone()].concat();
        AnalyzedQuery::build(|aq| {
            aq.name = "GetUsersWithOrders".to_string();
            aq.command = QueryCommand::Grouped;
            aq.sql = "SELECT u.id, u.name, u.email, o.id AS order_id, o.total, o.created_at AS order_date\nFROM users u\nJOIN orders o ON o.user_id = u.id".to_string();
            aq.columns = all_cols;
            aq.params = vec![];
            aq.deprecated = None;
            aq.source_table = None;
            aq.composites = vec![];
            aq.enums = vec![];
            aq.optional_params = vec![];
            aq.group_by = Some(GroupByConfig {
                table: "users".to_string(),
                key_column: "id".to_string(),
                parent_columns: parent_cols,
                child_columns: child_cols,
            });
            aq.custom = vec![];
        })
    }

    #[test]
    fn test_grouped_ruby_tiny_tds_structs() {
        let backend = RubyTinyTdsBackend::new("mssql").unwrap();
        let query = make_grouped_query();
        let result = crate::generate_with_backend(&query, &backend).unwrap();

        let row_struct = result.row_struct.as_deref().unwrap();
        assert!(
            row_struct.contains("GetUsersWithOrdersChildRow = Data.define(:order_id, :total, :order_date)"),
            "missing child struct; got:\n{row_struct}"
        );
        assert!(
            row_struct.contains("GetUsersWithOrdersRow = Data.define(:id, :name, :email, :children)"),
            "missing parent struct; got:\n{row_struct}"
        );
        let child_pos = row_struct.find("GetUsersWithOrdersChildRow").unwrap();
        let parent_pos = row_struct.find("GetUsersWithOrdersRow = Data.define").unwrap();
        assert!(child_pos < parent_pos, "child struct must appear before parent struct");
    }

    #[test]
    fn test_grouped_ruby_tiny_tds_query_fn() {
        let backend = RubyTinyTdsBackend::new("mssql").unwrap();
        let query = make_grouped_query();
        let result = crate::generate_with_backend(&query, &backend).unwrap();

        let query_fn = result.query_fn.as_deref().unwrap();
        assert!(
            query_fn.contains("def self.get_users_with_orders(client)"),
            "missing fn; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("client.execute("),
            "must use client.execute; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("key = row[\"id\"]"),
            "must access key by string; got:\n{query_fn}"
        );
        assert!(query_fn.contains("_index = {}"), "must use _index; got:\n{query_fn}");
        assert!(
            query_fn.contains("GetUsersWithOrdersChildRow.new("),
            "must construct child struct; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("GetUsersWithOrdersRow.new(**e)"),
            "must fold into parent; got:\n{query_fn}"
        );
    }
}