package parse

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

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

	// From the specs: "Whitespace means tab (0x09) or space (0x20)."
	// In this package, we name this a blank, to be in line with the
	// terminology as used in parsekit.
	blank          = a.Runes('\t', ' ')
	blanks         = c.OneOrMore(blank)
	optionalBlanks = c.ZeroOrMore(blank)

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

	// Whitespace is defined as blanks + newlines.
	whitespace         = c.OneOrMore(blank.Or(newline))
	optionalWhitespace = c.ZeroOrMore(blank.Or(newline))

	// 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, c.ZeroOrMore(c.Not(a.EndOfLine)))
	optionalComment = c.Optional(comment)

	endOfLineOrComment          = c.Seq(optionalBlanks, optionalComment, a.EndOfLine)
	whitespaceOrComment         = whitespace.Or(comment)
	optionalWhitespaceOrComment = c.ZeroOrMore(whitespaceOrComment)
)

type parser struct {
	doc *ast.Document
}

func newParser() *parser {
	doc := ast.NewDocument()
	return &parser{doc}
}

// Run the TOML parser against the provided input data.
//
// For an overview of allowed inputs, take a look at the documentation for
// parsekit.read.New(). At the time of writing, you can make use of
// strings, types implementing io.Reader and bufio.Readers.
//
// This function returns a TOML abstract syntax table structure and an
// error (or nil when no error occurred). When an error occurred, the
// TOML ast struct will contain the data that could be parsed up to the error.
func Run(input interface{}) (ast.Table, error) {
	p := newParser()
	err := parse.New(p.startDocument)(input)
	return p.doc.Root, err
}