package varaq

import (
	"fmt"
	"strings"
)

type Expr struct {
	Tok   TokenType
	Exprs []Expr
	Value any
	Count int
}

type Parser struct {
	tokens []Token
	pos    int
	end    int
}

func (p Parser) curr() Token {
	return p.tokens[p.pos]
}

func parse(p Parser, stop TokenType, tt TokenType) (Expr, int) {
	code := Expr{tt, make([]Expr, 0), nil, 0}

	for {
		if p.pos < 0 || p.pos > p.end-1 {
			break
		}

		if p.curr().Toktype == stop {
			p.pos += 1
			break
		}

		if p.curr().Toktype == LEFTBRACE {
			p.pos += 1
			ex, pos := parse(p, RIGHTBRACE, FUNCTION)
			p.pos = pos
			code.Exprs = append(code.Exprs, ex)
			code.Count += 1
		} else if p.curr().Toktype == LEFTPAREN {
			p.pos += 1
			ex, pos := parse(p, RIGHTPAREN, LIST)
			p.pos = pos
			code.Exprs = append(code.Exprs, ex)
			code.Count += 1
		} else {
			code.Exprs = append(code.Exprs, Expr{p.curr().Toktype, nil, p.curr().Literal, 0})
			p.pos += 1
		}
	}

	return code, p.pos
}

func Parse(tokens []Token) Expr {
	parser := Parser{tokens, 0, len(tokens)}
	ex, _ := parse(parser, EOF, SCRIPT)
	return ex
}

func PrintDump(code Expr, depth int) {
	for _, c := range code.Exprs {
		if c.Tok == FUNCTION {
			depth += 1
			fmt.Printf("%s %s\n", strings.Repeat("-", depth), c.Tok)
			PrintDump(c, depth)
			depth -= 1
		} else if c.Tok == LIST {
			depth += 1
			fmt.Printf("%s %s\n", strings.Repeat("-", depth), c.Tok)
			PrintDump(c, depth)
			depth -= 1
		} else {
			fmt.Printf("%s %s: %v\n", strings.Repeat("-", depth), c.Tok, c.Value)
		}
	}
}