package parse

import (
	"git.makaay.nl/mauricem/go-parsekit/parse"
	"git.makaay.nl/mauricem/go-parsekit/tokenize"
)

// Some globally useful tokenizer definitions.
var (
	c, a, m, tok = tokenize.C, tokenize.A, tokenize.M, tokenize.T

	// Whitespace means tab (0x09) or space (0x20).
	// This matches the blanks as defined by parsekit.

	whitespace = a.Blanks.Optional()

	// Newline means LF (0x0A) or CRLF (0x0D0A).
	// This matches the newline as defined by parsekit.

	newline = a.Newline

	// Whitespace + newlines.
	// This matches the whitespace as defined by parsekit.

	whitespaceInclNewlines = a.Whitespace

	// A '#' hash symbol marks the rest of the line as a comment.
	// All characters up to the end of the line are included in the comment.

	comment                      = c.Seq(a.Hash, a.UntilEndOfLine.Optional())
	optionalComment              = comment.Optional()
	endOfLineOrComment           = c.Seq(whitespace, optionalComment, a.EndOfLine)
	whitespaceNewlinesOrComments = whitespaceInclNewlines.Or(comment)

	// Keys may be either bare or quoted.
	detectKey = a.ByteByCallback(func(b byte) bool {
		return isBareKeyRune(b) || b == '\'' || b == '"'
	})

	// Both [tables] and [[arrays of tables]] start with a square open bracket.
	detectTable = a.SquareOpen
)

func (t *parser) startDocument(p *parse.API) {
	for {
		switch {
		case p.Skip(whitespaceNewlinesOrComments):
			// NOOP
		case p.Peek(detectKey):
			p.Handle(t.startKeyValuePair)
		case p.Peek(detectTable):
			p.Handle(t.startTable)
		case p.Skip(a.EndOfFile):
			p.Stop()
		default:
			p.Expected("key/value pair, table or array of tables")
			return
		}
		if p.IsStoppedOrInError() {
			return
		}
	}
}