qw 0.6.0

use anyhow::Result;
use inflector::Inflector;

pub struct FieldDef {
    pub name:     String,
    pub sql_type: String,
    pub not_null: bool,
    pub default:  Option<String>,
}

pub fn generate_migration_sql(model_name: &str, default_pk: bool, fields: &[FieldDef]) -> String {
    let table_name = model_name.to_snake_case().to_plural();
    let mut columns = vec![];

    if default_pk {
        columns.push(r#"    "id" bigint NOT NULL PRIMARY KEY"#.to_string());
    }

    for f in fields {
        let default = f.default.as_deref().map(|d| format!(" DEFAULT {d}")).unwrap_or_default();
        let constraint = if f.not_null { " NOT NULL" } else { "" };
        columns.push(format!(
            r#"    "{}" {}{}{}"#,
            f.name, f.sql_type, default, constraint
        ));
    }

    format!(
        r#"CREATE TABLE "{table_name}"
(
{}
);
"#,
        columns.join(
            ",
"
        )
    )
}

pub fn quote_default(sql_type: &str, value: &str) -> String {
    if matches!(sql_type, "varchar" | "timestamp") {
        format!("'{value}'")
    } else {
        value.to_string()
    }
}

pub fn generate_add_column_sql(table_name: &str, fields: &[FieldDef]) -> String {
    let columns = fields
        .iter()
        .map(|f| {
            let default = f.default.as_deref().map(|d| format!(" DEFAULT {d}")).unwrap_or_default();
            let constraint = if f.not_null { " NOT NULL" } else { "" };
            format!(
                r#"    ADD COLUMN "{}" {}{}{}"#,
                f.name, f.sql_type, default, constraint
            )
        })
        .collect::<Vec<_>>()
        .join(",\n");

    format!(
        r#"ALTER TABLE "{table_name}"
{columns};
"#
    )
}

pub fn write_migration(migrations_path: &str, name: &str, sql: &str) -> Result<String> {
    let timestamp = chrono::Utc::now().format("%Y%m%d%H%M%S");
    let filename = format!("{timestamp}_{name}.sql");
    let path = std::path::Path::new(migrations_path).join(&filename);
    std::fs::write(&path, sql)?;
    Ok(filename)
}