package dasmlbl

import (
	"strings"
	"strconv"
	"fmt"
)

type Parser struct {
	config *Config
	items chan LexItem
}

func NewParser(items chan LexItem) *Parser {
	return &Parser{
		config: &Config{},
		items: items,
	}
}

func (p *Parser) next() LexItem {
	select {
	case itm := <- p.items:
		//fmt.Println(itm)
		return itm
	}
	return LexItem{lex_EOF, "EOF"}
}

func (p *Parser) Run() (*Config, error) {
	for {
		itm := p.next()
		//fmt.Println("<", itm)
		if itm.typ == lex_EOF {
			break
		}

		if itm.typ == lex_Pound {
			itm = p.next()
			continue
		}

		if itm.typ != lex_Ident {
			continue
			//return nil, fmt.Errorf("expected ident, got %s", itm)
		}

		//if strings.ToLower(itm.val) != "label" {
		//	continue
		//}

		var err error
		switch strings.ToLower(itm.val) {
		case "label":
			err = p.parseLabel()
		case "range":
			err = p.parseRange()
		}

		if err != nil {
			return p.config, err
		}
	}
	return p.config, nil
}

func (p *Parser) parseRange() error {
	itm := p.next()
	if itm.typ != lex_OpenBracket {
		return fmt.Errorf("missing open bracket")
	}

	rng := Range{}
	for {
		itm = p.next()
		if itm.typ == lex_CloseBracket {
			break
		}

		if itm.typ != lex_Ident {
			return fmt.Errorf("missing ident")
		}

		switch strings.ToLower(itm.val) {
		case "name", "comment":
			typ := itm.val
			itm = p.next()
			if itm.typ != lex_String {
				return fmt.Errorf("%s requires string: %s", typ, itm)
				//return fmt.Errorf("name requires string")
			}

			switch typ {
			case "name":
				rng.Name = itm.val
			case "comment":
				rng.Comment = itm.val
			case "type":
				rng.Type = itm.val
			case "addrmode":
				rng.AddrMode = itm.val
			}

		case "type", "addrmode":
			itm = p.next()
			if itm.typ != lex_Ident {
				return fmt.Errorf("%s requires ident: %s", itm.val, itm)
			}
			rng.Type = itm.val

		case "start", "end", "unit":
			typ := itm.val
			itm = p.next()
			if itm.typ != lex_Number {
				return fmt.Errorf("%s: %s", strings.ToLower(typ+" requires number"), itm)
			}

			str := itm.val
			if strings.HasPrefix(str, "$") {
				str = "0x"+strings.TrimPrefix(str, "$")
			} else if strings.HasPrefix(str, "%") {
				str = "0b"+strings.TrimPrefix(str, "%")
			}

			val, err := strconv.ParseInt(str, 0, 32)
			if err != nil {
				return err
			}

			switch typ {
			case "start":
				rng.Start = int(val)
			case "end":
				rng.End = int(val)
			case "unit":
				rng.Unit = int(val)
			}
		}

		itm = p.next()
		if itm.typ != lex_Semicolon {
			return fmt.Errorf("[parseRange] missing semicolon")
		}
	}

	p.config.Ranges = append(p.config.Ranges, rng)
	return nil
}

func (p *Parser) parseLabel() error {
	itm := p.next()
	if itm.typ != lex_OpenBracket {
		return fmt.Errorf("missing open bracket")
	}

	lbl := Label{}
	for {
		itm = p.next()
		if itm.typ == lex_CloseBracket {
			break
		}

		if itm.typ != lex_Ident {
			return fmt.Errorf("missing ident")
		}

		//fmt.Println("]", itm)

		switch strings.ToLower(itm.val) {
		case "name":
			itm = p.next()
			if itm.typ != lex_String {
				return fmt.Errorf("name requires string: %s", itm)
			}
			lbl.Name = itm.val

		case "addr", "size", "paramsize":
			typ := strings.ToLower(itm.val)
			itm = p.next()
			if itm.typ != lex_Number {
				return fmt.Errorf("%s: %s", strings.ToLower(typ+" requires number"), itm)
			}

			str := itm.val
			if strings.HasPrefix(str, "$") {
				str = "0x"+strings.TrimPrefix(str, "$")
			} else if strings.HasPrefix(str, "%") {
				str = "0b"+strings.TrimPrefix(str, "%")
			}

			val, err := strconv.ParseInt(str, 0, 32)
			if err != nil {
				return err
			}

			switch typ {
			case "addr":
				lbl.Address = int(val)
			case "size":
				lbl.Size = int(val)
			case "paramsize":
				lbl.ParamSize = int(val)
			}

		case "comment":
			itm = p.next()
			if itm.typ != lex_String {
				return fmt.Errorf("comment requires string")
			}

			lbl.Comment = itm.val
		}

		itm = p.next()
		if itm.typ != lex_Semicolon {
			return fmt.Errorf("[parseLabel] missing semicolon; %#v", lbl)
		}
	}

	p.config.Labels = append(p.config.Labels, lbl)
	return nil
}

//func (p *Parser) parseIdent(itm LexItem) error {
//	switch strings.ToLower(itm.val) {
//	case "global":
//		select {
//		case itm = <- p.items:
//			if itm.typ != lex_OpenBracket {
//				return fmt.Errorf("expected { after global, got %q", itm)
//			}
//			return p.parseGlobal()
//		default:
//			return fmt.Errorf("early EOF")
//		}
//	}
//
//	return nil
//}

//func (p *Parser) parseGlobal() error {
//	for {
//		select {
//		case itm := <- p.items:
//		default:
//			return fmt.Errorf("early EOF")
//		}
//	}
//}