pg_tviews 0.1.0-beta.12

//! DDL Operations: TVIEW Creation and Management
//!
//! This module handles Data Definition Language operations for TVIEWs:
//! - **CREATE TABLE tv_ AS SELECT**: Parses SQL, creates metadata, sets up triggers
//! - **DROP TABLE tv_***: Cleans up metadata, removes triggers and views
//! - **Validation**: Ensures TVIEW names and SQL are valid
//!
//! ## Architecture
//!
//! DDL operations follow this sequence:
//! 1. Parse and validate TVIEW name (`tv_*` format)
//! 2. Analyze SELECT statement for column types and dependencies
//! 3. Create metadata entries in `pg_tview_meta`
//! 4. Set up triggers on base tables for change tracking
//! 5. Create the actual view with refresh triggers

pub mod convert;
pub mod create;
pub mod drop;

pub use convert::convert_existing_table_to_tview;
pub use create::create_tview;
pub use drop::drop_tview;

use pgrx::prelude::*;

/// SQL function: Create a TVIEW
///
/// Usage: SELECT `pg_tviews_create`('`my_entity`', 'SELECT id, name FROM users WHERE active = true');
#[pg_extern]
fn pg_tviews_create(tview_name: &str, select_sql: &str) -> Result<String, String> {
    crate::validation::validate_sql_identifier(tview_name, "tview_name")
        .map_err(|e| format!("Invalid TVIEW name: {e}"))?;

    // Ensure ProcessUtility hook is installed for DDL syntax support.
    // SAFETY: Called from PostgreSQL backend context, hook installation is valid.
    unsafe {
        crate::hooks::ensure_hook_installed();
    }

    match create_tview(tview_name, select_sql, None, false) {
        Ok(()) => Ok(format!("TVIEW '{tview_name}' created successfully")),
        Err(e) => Err(format!("Failed to create TVIEW: {e}")),
    }
}

/// SQL function: Drop a TVIEW
///
/// Usage: SELECT `pg_tviews_drop`('`my_entity`', true);        -- true = IF EXISTS
///        SELECT `pg_tviews_drop`('`my_entity`', true, true);  -- IF EXISTS + CASCADE
#[pg_extern]
fn pg_tviews_drop(
    tview_name: &str,
    if_exists: default!(bool, false),
    cascade: default!(bool, false),
) -> Result<String, String> {
    crate::validation::validate_sql_identifier(tview_name, "tview_name")
        .map_err(|e| format!("Invalid TVIEW name: {e}"))?;

    match drop_tview(tview_name, if_exists, cascade) {
        Ok(()) => Ok(format!("TVIEW '{tview_name}' dropped successfully")),
        Err(e) => Err(format!("Failed to drop TVIEW: {e}")),
    }
}

/// SQL function: Convert existing table to TVIEW (for benchmarking/testing)
///
/// Usage: SELECT `pg_tviews_convert_existing_table`('`tv_product`');
///
/// This function converts a table that was created with standard DDL
/// into a proper TVIEW structure with triggers and metadata.
///
/// Note: Different from the internal `pg_tviews_convert_table()` which is called
/// by event triggers during CREATE TABLE interception.
#[pg_extern]
fn pg_tviews_convert_existing_table(table_name: &str) -> Result<String, String> {
    crate::validation::validate_sql_identifier(table_name, "table_name")
        .map_err(|e| format!("Invalid table name: {e}"))?;

    match convert_existing_table_to_tview(table_name) {
        Ok(()) => Ok(format!(
            "Table '{table_name}' converted to TVIEW successfully"
        )),
        Err(e) => Err(format!("Failed to convert table to TVIEW: {e}")),
    }
}