package ast

import "git.akyoto.dev/cli/q/src/token"

// eachInstruction calls the function on each AST node.
func eachInstruction(tokens token.List, call func(token.List) error) error {
	start := 0
	groupLevel := 0
	blockLevel := 0

	for i, t := range tokens {
		switch t.Kind {
		case token.NewLine:
			if start == i {
				start = i + 1
				continue
			}

			if groupLevel > 0 || blockLevel > 0 {
				continue
			}

			err := call(tokens[start:i])

			if err != nil {
				return err
			}

			start = i + 1

		case token.GroupStart:
			groupLevel++

		case token.GroupEnd:
			groupLevel--

		case token.BlockStart:
			blockLevel++

		case token.BlockEnd:
			blockLevel--

			if groupLevel > 0 || blockLevel > 0 {
				continue
			}

			err := call(tokens[start : i+1])

			if err != nil {
				return err
			}

			start = i + 1

		case token.EOF:
			if start < i {
				return call(tokens[start:i])
			}

			return nil
		}
	}

	if start < len(tokens) {
		return call(tokens[start:])
	}

	return nil
}