database

type AlreadyMergedError struct {
	// File is the base name of the migration that was refused.
	File string
	// Version is the version it claims.
	Version uint64
	// MergeBaseMax is the high-water mark it is at or below.
	MergeBaseMax uint64
}

type Column struct {
	Name      string `json:"name"`
	Type      string `json:"type"`
	Nullable  bool   `json:"nullable"`
	Default   string `json:"default,omitempty"`
	IsPrimary bool   `json:"is_primary"`
	MaxLength *int   `json:"max_length,omitempty"`
	UDTName   string `json:"udt_name,omitempty"`
}

type ForeignKey struct {
	Name             string `json:"name"`
	Column           string `json:"column"`
	ReferencedTable  string `json:"referenced_table"`
	ReferencedColumn string `json:"referenced_column"`
}

type Index struct {
	Name    string   `json:"name"`
	Columns []string `json:"columns"`
	Unique  bool     `json:"unique"`
}

type MigrationContext struct {
	MigrationName     string
	CreatedAt         time.Time
	ParsedTables      []ParsedTable // Schema reconstructed from existing migrations
	LiveTables        []Table       // Schema from live DB introspection (if --dsn)
	PreviousMigration *PreviousMigrationInfo
	MigrationHistory  []string // List of all previous migration filenames
}

type MigrationOptions struct {
	DSN string // If set, introspect the live DB for schema
}

type MigrationService interface {
	CreateMigration(ctx context.Context, name string, dir string, opts *MigrationOptions) error
	GatherMigrationContext(ctx context.Context, name string, migDir string, opts MigrationOptions) (*MigrationContext, error)
	GetPreviousMigration(ctx context.Context, dir string) (*PreviousMigrationInfo, error)
	GetMigrationHistory(ctx context.Context, dir string) ([]string, error)
}

type ParsedColumn struct {
	Name       string
	Type       string
	Constraint string // e.g. "PRIMARY KEY", "NOT NULL", "UNIQUE", "REFERENCES users(id)"
}

type ParsedTable struct {
	Name    string
	Columns []ParsedColumn
}

type PreviousMigrationInfo struct {
	Filename string
	Content  string
}

type RebaseResult struct {
	OldPath string
	NewPath string
	// OldVersion and NewVersion are the numeric version prefixes, so a
	// caller can assert ordering without re-parsing the filenames.
	OldVersion uint64
	NewVersion uint64
}

type SchemaIntrospector interface {
	ConnectDB(ctx context.Context, dsn string) (*sql.DB, error)
	IntrospectSchema(ctx context.Context, db *sql.DB, tableFilter string) ([]Table, error)
	IntrospectTable(ctx context.Context, db *sql.DB, tableName string) (*Table, error)
}

type Table struct {
	Name        string       `json:"name"`
	Schema      string       `json:"schema"`
	Columns     []Column     `json:"columns"`
	PrimaryKey  []string     `json:"primary_key"`
	Indexes     []Index      `json:"indexes"`
	ForeignKeys []ForeignKey `json:"foreign_keys"`
}