#include "ruby-duckdb.h"

static VALUE cDuckDBResult;

static void deallocate(void *ctx)
{
    rubyDuckDBResult *p = (rubyDuckDBResult *)ctx;

    duckdb_destroy_result(&(p->result));
    xfree(p);
}

static VALUE allocate(VALUE klass)
{
    rubyDuckDBResult *ctx = xcalloc((size_t)1, sizeof(rubyDuckDBResult));
    return Data_Wrap_Struct(klass, NULL, deallocate, ctx);
}

static VALUE to_ruby_obj_boolean(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    bool bval = duckdb_value_boolean(result, col_idx, row_idx);
    return bval ? Qtrue : Qnil;
}

static VALUE to_ruby_obj_smallint(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    int16_t i16val = duckdb_value_int16(result, col_idx, row_idx);
    return INT2FIX(i16val);
}

static VALUE to_ruby_obj_integer(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    int32_t i32val = duckdb_value_int32(result, col_idx, row_idx);
    return INT2NUM(i32val);
}

static VALUE to_ruby_obj_bigint(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    int64_t i64val = duckdb_value_int64(result, col_idx, row_idx);
    return rb_int2big(i64val);
}

static VALUE to_ruby_obj_float(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    float fval = duckdb_value_float(result, col_idx, row_idx);
    return DBL2NUM(fval);
}

static VALUE to_ruby_obj_double(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    double dval = duckdb_value_double(result, col_idx, row_idx);
    return DBL2NUM(dval);
}

static VALUE to_ruby_obj(duckdb_result *result, index_t col_idx, index_t row_idx)
{
    char *p;
    VALUE obj = Qnil;
    if (result->columns[col_idx].nullmask[row_idx]) {
        return obj;
    }
    switch(result->columns[col_idx].type) {
    case DUCKDB_TYPE_BOOLEAN:
        return to_ruby_obj_boolean(result, col_idx, row_idx);
    case DUCKDB_TYPE_SMALLINT:
        return to_ruby_obj_smallint(result, col_idx, row_idx);
    case DUCKDB_TYPE_INTEGER:
        return to_ruby_obj_integer(result, col_idx, row_idx);
    case DUCKDB_TYPE_BIGINT:
        return to_ruby_obj_bigint(result, col_idx, row_idx);
    case DUCKDB_TYPE_FLOAT:
        return to_ruby_obj_float(result, col_idx, row_idx);
    case DUCKDB_TYPE_DOUBLE:
        return to_ruby_obj_double(result, col_idx, row_idx);
    default:
        p = duckdb_value_varchar(result, col_idx, row_idx);
        obj = rb_str_new2(p);
        free(p);
    }
    return obj;
}

static VALUE row_array(rubyDuckDBResult *ctx, index_t row_idx)
{
    index_t col_idx;
    VALUE ary = rb_ary_new2(ctx->result.column_count);
    for(col_idx = 0; col_idx < ctx->result.column_count; col_idx++) {
        rb_ary_store(ary, col_idx, to_ruby_obj(&(ctx->result), col_idx, row_idx));
    }
    return ary;
}

static VALUE duckdb_result_row_size(VALUE oDuckDBResult, VALUE args, VALUE obj)
{
    rubyDuckDBResult *ctx;
    Data_Get_Struct(oDuckDBResult, rubyDuckDBResult, ctx);

    return LONG2FIX(ctx->result.row_count);
}

static VALUE duckdb_result_each(VALUE oDuckDBResult)
{
    rubyDuckDBResult *ctx;
    index_t row_idx = 0;

    RETURN_SIZED_ENUMERATOR(oDuckDBResult, 0, 0, duckdb_result_row_size);

    Data_Get_Struct(oDuckDBResult, rubyDuckDBResult, ctx);
    for (row_idx = 0; row_idx < ctx->result.row_count; row_idx++) {
        rb_yield(row_array(ctx, row_idx));
    }
    return oDuckDBResult;
}

VALUE create_result(void)
{
    return allocate(cDuckDBResult);
}

void init_duckdb_result(void)
{
    cDuckDBResult = rb_define_class_under(mDuckDB, "Result", rb_cObject);
    rb_define_alloc_func(cDuckDBResult, allocate);

    rb_define_method(cDuckDBResult, "each", duckdb_result_each, 0);
}