import "Prelude" hiding (group)

importJava "java.util.regex.Pattern" where
    data Pattern
    
    compile :: String -> Pattern
    matcher :: Pattern -> String -> Matcher

importJava "java.util.regex.Matcher" where
    data Matcher

    matches :: Matcher -> <Proc> Boolean
    
    group :: Matcher -> <Proc> String

    @JavaName find
    matcherFind :: Matcher -> <Proc> Boolean
    
    appendReplacement :: Matcher -> StringBuffer -> String -> <Proc> Matcher
    appendTail :: Matcher -> StringBuffer -> <Proc> StringBuffer
    
    @JavaName replaceAll
    replaceAll_ :: Matcher -> String -> String
    
    @JavaName replaceFirst
    replaceFirst_ :: Matcher -> String -> String
    
    quoteReplacement :: String -> String

importJava "java.lang.StringBuffer" where
    data StringBuffer
    
    @JavaName "<init>"
    newStringBuffer :: () -> StringBuffer
    
    @JavaName toString
    freezeStringBuffer :: StringBuffer -> <Proc> String

"""
@replaceAll pattern replacement text@ replaces all matches of @pattern@ in the @text@
by @replacement@.
"""    
replaceAll :: String -> String -> String -> String
replaceAll pattern replacement text = 
    replaceAll_ (matcher (compile pattern) text) replacement 
    
"""
@replaceFirst pattern replacement text@ replaces the first match of @pattern@ in the @text@
by @replacement@.
"""    
replaceFirst :: String -> String -> String -> String
replaceFirst pattern replacement text = 
    replaceFirst_ (matcher (compile pattern) text) replacement 

"""
@substituteAll pattern f text@ replaces all matches of @pattern@ in the @text@
by the string returned by @f@ given the matched region of the string as a parameter.
"""
substituteAll :: String -> (String -> String) -> String -> String
substituteAll pattern f text = runProc do
    m = matcher (compile pattern) text
    buf = newStringBuffer ()
    while (matcherFind m) do
        appendReplacement m buf $ f $ group m
    appendTail m buf
    freezeStringBuffer buf


"""
@substituteFirst pattern f text@ replaces the first match of @pattern@ in the @text@
by the string returned by @f@ given the matched region of the string as a parameter.
"""
substituteFirst :: String -> (String -> String) -> String -> String
substituteFirst pattern f text = runProc do
    m = matcher (compile pattern) text
    if (matcherFind m) then do
        buf = newStringBuffer ()    
        appendReplacement m buf $ f $ group m
        appendTail m buf
        freezeStringBuffer buf
    else text