rudof_cli 0.3.15

use crate::cli::parser::QueryArgs;
use crate::cli::wrappers::resolve_backend;
use crate::commands::base::{Command, CommandContext};
use crate::commands::connect::ConnectionDetails;
use anyhow::{Context, Result};
use lbug::{Connection, Database, SystemConfig};
use rudof_lib::formats::BackendSpec;
use std::io::Write;

/// Implementation of the `query` command.
///
/// This struct holds the specific arguments parsed by `clap` and
/// implements the [Command] trait to execute Query command logic.
pub struct QueryCommand {
    /// Arguments specific to Query command.
    args: QueryArgs,
}

impl QueryCommand {
    pub fn new(args: QueryArgs) -> Self {
        Self { args }
    }
}

impl Command for QueryCommand {
    /// Returns the unique identifier for this command.
    fn name(&self) -> &'static str {
        "query"
    }

    /// Executes the Query command logic.
    ///
    /// With no `--query`, there is no new query to run, so this just
    /// re-serializes the results of the last query run in the session
    /// (useful in the interactive shell, where state persists across
    /// commands).
    fn execute(&self, ctx: &mut CommandContext) -> Result<()> {
        // Cypher mode: query a LadybugDB database instead of the RDF/SPARQL
        // pipeline (supports other query languages per the `query` verb, see
        // discussion #747).
        if let Some(cypher) = &self.args.cypher {
            return execute_cypher(cypher, &self.args, ctx);
        }

        let data_format = self.args.data_format.into();
        let reader_mode = self.args.reader_mode.into();
        let query_type = self.args.query_type.into();
        let result_query_format = self.args.result_query_format.into();

        let backend = resolve_backend(&self.args.common);
        let has_data_source = !self.args.data.is_empty() || matches!(backend, BackendSpec::Endpoint(_));

        if has_data_source {
            let mut loading = ctx
                .rudof
                .load_data()
                .with_data_format(&data_format)
                .with_reader_mode(&reader_mode)
                .with_backend(backend);
            if !self.args.data.is_empty() {
                loading = loading.with_data(&self.args.data);
            }
            if let Some(base) = self.args.base.as_deref() {
                loading = loading.with_base(base);
            }
            loading.execute()?;
        }

        match &self.args.query {
            Some(query) => {
                ctx.rudof
                    .load_sparql_query(query)
                    .with_query_type(&query_type)
                    .execute()?;

                ctx.rudof
                    .run_query()
                    .with_result_query_format(&result_query_format)
                    .execute()?;
            },
            None if ctx.rudof.query_results().is_none() && !ctx.rudof.has_sparql_query() => {
                anyhow::bail!("No query specified. Use --query/-q to provide a SPARQL query to run.");
            },
            // A query was loaded without being run yet (e.g. via `sparql
            // -q FILE`, which only loads and shows) — run it now, since
            // `sparql` and `query` share the same loaded-query state.
            None if ctx.rudof.query_results().is_none() => {
                ctx.rudof
                    .run_query()
                    .with_result_query_format(&result_query_format)
                    .execute()?;
            },
            None => {},
        }

        ctx.rudof
            .serialize_query_results(&mut ctx.writer)
            .with_result_query_format(&result_query_format)
            .execute()?;

        Ok(())
    }
}

// ============================================================================
// Cypher mode (query a LadybugDB database)
// ============================================================================

/// Run a Cypher query against a LadybugDB database given by `--db` or by the
/// connection details file written by `rudof connect`.
fn execute_cypher(cypher: &str, args: &QueryArgs, ctx: &mut CommandContext) -> Result<()> {
    let details = ConnectionDetails::resolve(args.db.as_deref(), args.connection.as_deref())?;
    let config = SystemConfig::default().read_only(details.read_only || args.read_only);

    let db = Database::new(&details.path, config)
        .with_context(|| format!("Failed to open LadybugDB database at '{}'", details.path.display()))?;
    let conn = Connection::new(&db).context("Failed to connect to LadybugDB")?;

    let result = conn.query(cypher).context("Cypher query failed")?;

    writeln!(
        ctx.writer,
        "Query result ({} tuples, {} columns):",
        result.get_num_tuples(),
        result.get_num_columns()
    )?;
    writeln!(ctx.writer, "Columns: {:?}", result.get_column_names())?;
    writeln!(
        ctx.writer,
        "Compiling time: {:.2}ms, Execution time: {:.2}ms",
        result.get_compiling_time(),
        result.get_execution_time()
    )?;

    // Iterate over the result
    for row in result {
        writeln!(ctx.writer, "  {:?}", row)?;
    }

    Ok(())
}