// SPDX-FileCopyrightText: 2025 The Project Pterodactyl Developers
//
// SPDX-License-Identifier: MPL-2.0

import Foundation

public struct ImportParser {
	private var lexer: PterodactylSyntax.Lexer
	public private(set) var imports: [String] = []

	public init(input: String) {
		self.lexer = PterodactylSyntax.Lexer(input: input)
	}

	public mutating func parseHeader() {
		while true {
			guard let token = nextSignificantToken() else { return }
			switch token.kind {
			case .keyword(.import): parseImportStatement()
			default: return
			}
		}
	}

	/// Returns the next non-whitespace token.
	private mutating func nextSignificantToken() -> Token? {
		var token = lexer.nextToken()
		while token?.kind.isTrivia == true {
			token = lexer.nextToken()
		}

		guard let token else { return nil }
		return Token(kind: token.kind, text: token.text)
	}

	/// Parses a single `import xyz` line.
	private mutating func parseImportStatement() {
		guard let next = nextSignificantToken() else { return }
		guard next.kind == .identifier else { return }
		imports.append(next.text)
	}
}