package style

import  "github.com/yhirose/go-peg"    
import "fmt"
import "os"
import "io/ioutil"
import "errors"

const CSS1PEG = 
`
# CSS1 parser for a PEG parser generator.
# and a user command parser
# Doesn't support import statements.


STYLESHEET      ← (CDO / CDC)*  (RULESET/DECLARATIONS/COMMENT/ATRULE)* (CDO / CDC)*
RULESET         ← SELECTORS "{" DECLARATIONS? "}"
SELECTORS       ← SELECTOR ("," SELECTOR)*
SELECTOR        ← ( "*" / NAME ID? CLASS? PSEUDO_CLASS? /
                  ID CLASS? PSEUDO_CLASS? /
                  CLASS PSEUDO_CLASS? /
                  PSEUDO_CLASS )+ PSEUDO_ELEMENT* / PSEUDO_ELEMENT 
ATRULE          ← ATID (STRING / URL) ";" / ATID "{" DECLARATIONS "}" 
NAME            ← <IDENT>
DECLARATIONS    ← DECLARATION (';' DECLARATION)* ';'?
DECLARATION     ← NAME ":" EXPR PRIO? / COMMENT 
OPERATOR        ← '/' / ','
# UNARY_OPERATOR  ← '-' / '+'
PRIO            ← IMPORTANT
EXPR            ← TERM (OPERATOR TERM)*
TERM            ← STRING / PERCENTAGE / LENGTH / HEXCOLOR / URL / RGB / NUM / IDENT
~COMMENT        ←  "/*" (!("*/").)* "*/"
ATID            ← < "@" [a-zA-Z][-_a-zA-Z0-9]+ >
IMPORTANT       ← < "!" WS "important" >
IDENT           ← < [-_a-zA-Z][-_a-zA-Z0-9]* >
PERCENTAGE      ← < NUM > "%"
NUM             ← < [+-]*[0-9]+ / [0-9]* "." [0-9]+ >
LENGTH          ← NUM UNIT 
UNIT            ← <"pt" / "mm" / "pt" / "in" / "px" / "em" / "ex" >
PSEUDO_ELEMENT  ←  <":first-letter" / ":first-line" >
PSEUDO_CLASS    ←  <":hover" / ":link" / ":mark" / ":active" / ":visited" >
HEXCOLOR        ← "#" < ([0-9a-fA-F])+ > 
ID              ← "#" < IDENT >
CLASS           ← "." < IDENT >

# Raw string macro.
RAWSM(O,C)          ← O < (!(C).)* > C
# Escaped string macro.
ESCSM(O,C)          ← O < (!(C)STRCHAR)* > C
# String escapes
STRESC1      ← "\\" [nrtfv\'\\"\[\]\\]
STRESC2      ← "\\" [0-3] [0-7] [0-7]
STRESC3      ← "\\" [0-7] [0-7]*
STRESC4      ← "\\x" [0-9a-fA-F] [0-9a-fA-F]?
STRESC5      ← "\\u" [0-9a-fA-F]+
STRNOESC     ← (!('\\\\').)
STRCHAR      ←   STRESC1 / STRESC2 / STRESC3 / STRESC4 / STRESC5 / STRNOESC  
# Strings
STRING       ← ESCSM("\"", "\"") / ESCSM("'", "'")
URL                 ← "url(" STRING  ")"
RGB                 ← < "rgb("[ \t]*[0-9]+[ \t]* "," [ \t]*[0-9]+[ \t]* "," [ \t]*[0-9]+[ \t]*  ")" >
~WS                 ←   [ \t\n\r]*
CDO                 ←   "<!--"
CDC                 ←   "-->"
%whitespace         ←   [ \t\n\r]*
`



type CSS1Parser struct {
    *peg.Parser
}

type CSS1Result struct {
    * peg.Ast
}

func parserCheck(err error) {
    if perr, ok := err.(*peg.Error); ok {
        for _, d := range perr.Details {
            fmt.Println(d)
        }
        os.Exit(1)
    }
}

/** Creates a CS1 PEG parser. */
func NewCSS1Parser() (*CSS1Parser, error) {
    result := &CSS1Parser{}
    var err error
    result.Parser, err = peg.NewParser(CSS1PEG)
    if err == nil {
        result.EnableAst()            
    }
    return result, err
}

var defaultCSS1Parser * CSS1Parser

func InitDefaultParser() error {
    var err error
    defaultCSS1Parser, err = NewCSS1Parser()
    return err
}

func wrapResult(wrapme peg.Any) *CSS1Result {
    result := &CSS1Result{};
    ast, ok := wrapme.(*peg.Ast)
    if ok {
        result.Ast = ast
        return result
    } 
    return nil    
}

func (parser CSS1Parser) Parse(source string) (*CSS1Result, error) {
    ast, err := parser.ParseAndGetValue(source, nil)
    return wrapResult(ast), err
}

func (parser CSS1Parser) ParseFile(filename string) (*CSS1Result, error) {    
    source, err := ioutil.ReadFile(filename)
    if err == nil {
        return parser.Parse(string(source))
    } else {
        return nil, err
    }
}

func (css1 CSS1Result) InitializeTheme(theme * Theme) {
}

func parse(source string) (*CSS1Result, error) {
    if defaultCSS1Parser == nil {
        return nil, errors.New("Default parser not initialized!")
    }
    return defaultCSS1Parser.Parse(source)
}

func parseFile(filename string) (*CSS1Result, error) {
    if defaultCSS1Parser == nil {
        return nil, errors.New("Default parser not initialized!")
    }
    return defaultCSS1Parser.ParseFile(filename)
}