#include "duckdb/main/capi_internal.hpp"
#include "duckdb/common/types/timestamp.hpp"

namespace duckdb {

template <class T>
void WriteData(duckdb_result *out, ChunkCollection &source, idx_t col) {
	idx_t row = 0;
	auto target = (T *)out->columns[col].data;
	for (auto &chunk : source.Chunks()) {
		auto source = FlatVector::GetData<T>(chunk->data[col]);
		auto &mask = FlatVector::Validity(chunk->data[col]);

		for (idx_t k = 0; k < chunk->size(); k++, row++) {
			if (!mask.RowIsValid(k)) {
				continue;
			}
			target[row] = source[k];
		}
	}
}

duckdb_state duckdb_translate_result(MaterializedQueryResult *result, duckdb_result *out) {
	D_ASSERT(result);
	if (!out) {
		// no result to write to, only return the status
		return result->success ? DuckDBSuccess : DuckDBError;
	}
	memset(out, 0, sizeof(duckdb_result));
	if (!result->success) {
		// write the error message
		out->error_message = strdup(result->error.c_str());
		return DuckDBError;
	}
	// copy the data
	// first write the meta data
	out->column_count = result->types.size();
	out->row_count = result->collection.Count();
	out->rows_changed = 0;
	if (out->row_count > 0 && StatementTypeReturnChanges(result->statement_type)) {
		// update total changes
		auto row_changes = result->GetValue(0, 0);
		if (!row_changes.is_null && row_changes.TryCastAs(LogicalType::BIGINT)) {
			out->rows_changed = row_changes.GetValue<int64_t>();
		}
	}
	out->columns = (duckdb_column *)duckdb_malloc(sizeof(duckdb_column) * out->column_count);
	if (!out->columns) { // LCOV_EXCL_START
		// malloc failure
		return DuckDBError;
	} // LCOV_EXCL_STOP

	// zero initialize the columns (so we can cleanly delete it in case a malloc fails)
	memset(out->columns, 0, sizeof(duckdb_column) * out->column_count);
	for (idx_t i = 0; i < out->column_count; i++) {
		out->columns[i].type = ConvertCPPTypeToC(result->types[i]);
		out->columns[i].name = strdup(result->names[i].c_str());
		out->columns[i].nullmask = (bool *)duckdb_malloc(sizeof(bool) * out->row_count);
		out->columns[i].data = duckdb_malloc(GetCTypeSize(out->columns[i].type) * out->row_count);
		if (!out->columns[i].nullmask || !out->columns[i].name || !out->columns[i].data) { // LCOV_EXCL_START
			// malloc failure
			return DuckDBError;
		} // LCOV_EXCL_STOP
	}
	// now write the data
	for (idx_t col = 0; col < out->column_count; col++) {
		// first set the nullmask
		idx_t row = 0;
		for (auto &chunk : result->collection.Chunks()) {
			for (idx_t k = 0; k < chunk->size(); k++) {
				out->columns[col].nullmask[row++] = FlatVector::IsNull(chunk->data[col], k);
			}
		}
		// then write the data
		switch (result->types[col].id()) {
		case LogicalTypeId::BOOLEAN:
			WriteData<bool>(out, result->collection, col);
			break;
		case LogicalTypeId::TINYINT:
			WriteData<int8_t>(out, result->collection, col);
			break;
		case LogicalTypeId::SMALLINT:
			WriteData<int16_t>(out, result->collection, col);
			break;
		case LogicalTypeId::INTEGER:
			WriteData<int32_t>(out, result->collection, col);
			break;
		case LogicalTypeId::BIGINT:
			WriteData<int64_t>(out, result->collection, col);
			break;
		case LogicalTypeId::UTINYINT:
			WriteData<uint8_t>(out, result->collection, col);
			break;
		case LogicalTypeId::USMALLINT:
			WriteData<uint16_t>(out, result->collection, col);
			break;
		case LogicalTypeId::UINTEGER:
			WriteData<uint32_t>(out, result->collection, col);
			break;
		case LogicalTypeId::UBIGINT:
			WriteData<uint64_t>(out, result->collection, col);
			break;
		case LogicalTypeId::FLOAT:
			WriteData<float>(out, result->collection, col);
			break;
		case LogicalTypeId::DOUBLE:
			WriteData<double>(out, result->collection, col);
			break;
		case LogicalTypeId::DATE:
			WriteData<date_t>(out, result->collection, col);
			break;
		case LogicalTypeId::TIME:
			WriteData<dtime_t>(out, result->collection, col);
			break;
		case LogicalTypeId::TIMESTAMP:
			WriteData<timestamp_t>(out, result->collection, col);
			break;
		case LogicalTypeId::VARCHAR: {
			idx_t row = 0;
			auto target = (const char **)out->columns[col].data;
			for (auto &chunk : result->collection.Chunks()) {
				auto source = FlatVector::GetData<string_t>(chunk->data[col]);
				for (idx_t k = 0; k < chunk->size(); k++) {
					if (!FlatVector::IsNull(chunk->data[col], k)) {
						target[row] = (char *)duckdb_malloc(source[k].GetSize() + 1);
						assert(target[row]);
						memcpy((void *)target[row], source[k].GetDataUnsafe(), source[k].GetSize());
						auto write_arr = (char *)target[row];
						write_arr[source[k].GetSize()] = '\0';
					} else {
						target[row] = nullptr;
					}
					row++;
				}
			}
			break;
		}
		case LogicalTypeId::BLOB: {
			idx_t row = 0;
			auto target = (duckdb_blob *)out->columns[col].data;
			for (auto &chunk : result->collection.Chunks()) {
				auto source = FlatVector::GetData<string_t>(chunk->data[col]);
				for (idx_t k = 0; k < chunk->size(); k++) {
					if (!FlatVector::IsNull(chunk->data[col], k)) {
						target[row].data = (char *)duckdb_malloc(source[k].GetSize());
						target[row].size = source[k].GetSize();
						assert(target[row].data);
						memcpy((void *)target[row].data, source[k].GetDataUnsafe(), source[k].GetSize());
					} else {
						target[row].data = nullptr;
						target[row].size = 0;
					}
					row++;
				}
			}
			break;
		}
		case LogicalTypeId::TIMESTAMP_NS:
		case LogicalTypeId::TIMESTAMP_MS:
		case LogicalTypeId::TIMESTAMP_SEC: {
			idx_t row = 0;
			auto target = (timestamp_t *)out->columns[col].data;
			for (auto &chunk : result->collection.Chunks()) {
				auto source = FlatVector::GetData<timestamp_t>(chunk->data[col]);

				for (idx_t k = 0; k < chunk->size(); k++) {
					if (!FlatVector::IsNull(chunk->data[col], k)) {
						if (result->types[col].id() == LogicalTypeId::TIMESTAMP_NS) {
							target[row] = Timestamp::FromEpochNanoSeconds(source[k].value);
						} else if (result->types[col].id() == LogicalTypeId::TIMESTAMP_MS) {
							target[row] = Timestamp::FromEpochMs(source[k].value);
						} else {
							D_ASSERT(result->types[col].id() == LogicalTypeId::TIMESTAMP_SEC);
							target[row] = Timestamp::FromEpochSeconds(source[k].value);
						}
					}
					row++;
				}
			}
			break;
		}
		case LogicalTypeId::HUGEINT: {
			idx_t row = 0;
			auto target = (duckdb_hugeint *)out->columns[col].data;
			for (auto &chunk : result->collection.Chunks()) {
				auto source = FlatVector::GetData<hugeint_t>(chunk->data[col]);
				for (idx_t k = 0; k < chunk->size(); k++) {
					if (!FlatVector::IsNull(chunk->data[col], k)) {
						target[row].lower = source[k].lower;
						target[row].upper = source[k].upper;
					}
					row++;
				}
			}
			break;
		}
		case LogicalTypeId::INTERVAL: {
			idx_t row = 0;
			auto target = (duckdb_interval *)out->columns[col].data;
			for (auto &chunk : result->collection.Chunks()) {
				auto source = FlatVector::GetData<interval_t>(chunk->data[col]);
				for (idx_t k = 0; k < chunk->size(); k++) {
					if (!FlatVector::IsNull(chunk->data[col], k)) {
						target[row].days = source[k].days;
						target[row].months = source[k].months;
						target[row].micros = source[k].micros;
					}
					row++;
				}
			}
			break;
		}
		default: // LCOV_EXCL_START
			// unsupported type for C API
			D_ASSERT(0);
			return DuckDBError;
		} // LCOV_EXCL_STOP
	}
	return DuckDBSuccess;
}

} // namespace duckdb

static void duckdb_destroy_column(duckdb_column column, idx_t count) {
	if (column.data) {
		if (column.type == DUCKDB_TYPE_VARCHAR) {
			// varchar, delete individual strings
			auto data = (char **)column.data;
			for (idx_t i = 0; i < count; i++) {
				if (data[i]) {
					duckdb_free(data[i]);
				}
			}
		} else if (column.type == DUCKDB_TYPE_BLOB) {
			// blob, delete individual blobs
			auto data = (duckdb_blob *)column.data;
			for (idx_t i = 0; i < count; i++) {
				if (data[i].data) {
					duckdb_free((void *)data[i].data);
				}
			}
		}
		duckdb_free(column.data);
	}
	if (column.nullmask) {
		duckdb_free(column.nullmask);
	}
	if (column.name) {
		duckdb_free(column.name);
	}
}

void duckdb_destroy_result(duckdb_result *result) {
	if (result->error_message) {
		duckdb_free(result->error_message);
	}
	if (result->columns) {
		for (idx_t i = 0; i < result->column_count; i++) {
			duckdb_destroy_column(result->columns[i], result->row_count);
		}
		duckdb_free(result->columns);
	}
	memset(result, 0, sizeof(duckdb_result));
}

const char *duckdb_column_name(duckdb_result *result, idx_t col) {
	if (!result || col >= result->column_count) {
		return nullptr;
	}
	return result->columns[col].name;
}

duckdb_type duckdb_column_type(duckdb_result *result, idx_t col) {
	if (!result || col >= result->column_count) {
		return DUCKDB_TYPE_INVALID;
	}
	return result->columns[col].type;
}

idx_t duckdb_column_count(duckdb_result *result) {
	if (!result) {
		return 0;
	}
	return result->column_count;
}

idx_t duckdb_row_count(duckdb_result *result) {
	if (!result) {
		return 0;
	}
	return result->row_count;
}

idx_t duckdb_rows_changed(duckdb_result *result) {
	if (!result) {
		return 0;
	}
	return result->rows_changed;
}

void *duckdb_column_data(duckdb_result *result, idx_t col) {
	if (!result || col >= result->column_count) {
		return nullptr;
	}
	return result->columns[col].data;
}

bool *duckdb_nullmask_data(duckdb_result *result, idx_t col) {
	if (!result || col >= result->column_count) {
		return nullptr;
	}
	return result->columns[col].nullmask;
}

char *duckdb_result_error(duckdb_result *result) {
	if (!result) {
		return nullptr;
	}
	return result->error_message;
}