package handlers

import (
	"encoding/json"
	"log"
)

// ParseSchemaVersion extracts the schema_version from a package manifest.
func ParseSchemaVersion(manifest any) int {
	switch m := manifest.(type) {
	case map[string]any:
		if v, ok := m["schema_version"].(float64); ok {
			return int(v)
		}
	case json.RawMessage:
		var s struct {
			SchemaVersion int `json:"schema_version"`
		}
		if err := json.Unmarshal(m, &s); err == nil {
			return s.SchemaVersion
		}
	}
	return 0
}

// RunSchemaMigrations logs a schema version change during package update.
//
// Only additive schema changes are supported: extensions can ADD columns and
// tables via db_tables in the manifest, but cannot modify or delete existing
// schema. If a migration between versions requires destructive changes,
// uninstall and reinstall the package manually.
func RunSchemaMigrations(ctx any, sandbox any, stores any, db any, isPostgres bool, packageID string, manifest any, fromVersion, toVersion int) error {
	log.Printf("[pkg-migrate] %s: schema version %d → %d (only additive changes are applied automatically; destructive migrations require manual uninstall/reinstall)", packageID, fromVersion, toVersion)
	return nil
}