#pragma once

// The schema migrator. Numbered SQL files in store/migrations/ are embedded at build time
// (see embed_migrations.cmake). On startup the daemon calls migrate_to_head(db): every
// migration whose version exceeds PRAGMA user_version is applied in order, each in its own
// transaction, and user_version is advanced to match.
//
// Forward-only: a released migration is immutable. The forward-only test in
// daemon/tests replays from every prior released user_version to head.

#include <cstdint>
#include <span>
#include <string_view>

#include "store/sqlite.hpp"

namespace velox::daemon::store {

struct Migration {
    std::int64_t version;      // 1, 2, 3, ... ; matches the NNNN_ prefix
    std::string_view name;     // e.g. "0001_initial"
    std::string_view sql;      // the file body
};

// The embedded set, sorted by version ascending. Defined in the generated header.
std::span<const Migration> embedded_migrations();

struct MigrationOutcome {
    std::int64_t from_version = 0;
    std::int64_t to_version = 0;
    int applied = 0;
};

// Apply every migration newer than db.user_version(). A no-op (applied == 0) when the DB
// is already at or beyond the highest embedded version.
DbResult<MigrationOutcome> migrate_to_head(Db& db);

}  // namespace velox::daemon::store