package core

/* Branch represents a named line of development.
 * Uses SVN-style global revision numbering - a branch is just a name,
 * revisions are still globally sequential (r123 on port, r124 on feature/x). */

type Branch struct {
	Name        string `json:"name"`         // "port", "feature/foo", "release/1.0"
	HeadRev     int64  `json:"head_rev"`     // current tip revision number
	CreatedAt   int64  `json:"created_at"`   // unix timestamp
	CreatedFrom int64  `json:"created_from"` // revision number this branch was created from
}

// DefaultBranchName is the default branch name (like SVN's trunk, but we call it "port")
const DefaultBranchName = "port"

// BranchNameValid checks if a branch name is valid
func BranchNameValid(name string) bool {
	if len(name) == 0 || len(name) > 255 {
		return false
	}

	/* NOTE(kroot): branch names follow simple rules:
	 * - no leading/trailing slashes
	 * - no double slashes
	 * - no special chars except / - _ .
	 * - no reserved names */

	for i, r := range name {
		switch {
		case r >= 'a' && r <= 'z':
			continue
		case r >= 'A' && r <= 'Z':
			continue
		case r >= '0' && r <= '9':
			continue
		case r == '-' || r == '_' || r == '.':
			continue
		case r == '/':
			/* no leading slash */
			if i == 0 {
				return false
			}
			/* no trailing slash */
			if i == len(name)-1 {
				return false
			}
			/* no double slashes */
			if i > 0 && name[i-1] == '/' {
				return false
			}
			continue
		default:
			return false
		}
	}

	return true
}