REBOL []

if not exists? %libwmp3.dll [
    write/binary %libwmp3.dll
    read/binary http://musiclessonz.com/rebol_tutorial/libwmp3.dll
]

lib: load/library %libwmp3.dll

Mp3_Initialize: make routine! [
    return: [integer!]
] lib "Mp3_Initialize"

Mp3_OpenFile: make routine! [
    return: [integer!] 
    class [integer!] 
    filename [string!]
    nWaveBufferLengthMs [integer!]
    nSeekFromStart [integer!] 
    nFileSize [integer!]
] lib "Mp3_OpenFile"

Mp3_Play: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Play"

Mp3_Stop: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Stop"

Mp3_Destroy: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Destroy"

Mp3_GetStatus: make routine! [
    return: [integer!] 
    initialized [integer!] 
    status [struct! []]
] lib "Mp3_GetStatus"

status: make struct! [
    fPlay [integer!] 
    fPause [integer!] 
    fStop [integer!] 
    fEcho [integer!] 
    nSfxMode [integer!] 
    fExternalEQ [integer!] 
    fInternalEQ [integer!] 
    fVocalCut [integer!] 
    fChannelMix [integer!] 
    fFadeIn [integer!] 
    fFadeOut [integer!] 
    fInternalVolume [integer!] 
    fLoop [integer!] 
    fReverse [integer!] 
] none

Mp3_Time: make struct! [
    ms [integer!] 
    sec [integer!]
    bytes [integer!] 
    frames [integer!] 
    hms_hour [integer!] 
    hms_minute [integer!] 
    hms_second [integer!] 
    hms_millisecond [integer!] 
] none

TIME_FORMAT_SEC: 2
SONG_BEGIN: 1
SONG_CURRENT_FORWARD: 4

Mp3_Seek: make routine! [
    return: [integer!] 
    initialized [integer!]
    fFormat [integer!]
    pTime [struct! []]
    nMoveMethod [integer!]
] lib "Mp3_Seek"

Mp3_PlayLoop: make routine! [
    return: [integer!] 
    initialized [integer!]
    fFormatStartTime [integer!]
    pStartTime [struct! []]
    fFormatEndTime [integer!] 
    pEndTime [struct! []]
    nNumOfRepeat [integer!] 
] lib "Mp3_PlayLoop"

Mp3_GetSongLength: make routine! [
    return: [integer!]
    initialized [integer!]
    pLength [struct! []]
] lib "Mp3_GetSongLength"

Mp3_GetPosition: make routine! [
    return: [integer!] 
    initialized [integer!]
    pTime [struct! []]
] lib "Mp3_GetPosition"

Mp3_Pause: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Pause"

Mp3_Resume: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Resume"

Mp3_SetVolume: make routine! [
    return: [integer!] 
    initialized [integer!]
    nLeftVolume [integer!]
    nRightVolume [integer!]
] lib "Mp3_SetVolume"

Mp3_GetVolume: [
    initialized [integer!]
    pnLeftVolume [integer!]
    pnRightVolume [integer!]
    return: [integer!]
] lib "Mp3_GetVolume"

Mp3_VocalCut: make routine! [
    return: [integer!] 
    initialized [integer!]
    fEnable [integer!]
] lib "Mp3_VocalCut"

Mp3_ReverseMode: make routine! [
    return: [integer!] 
    initialized [integer!]
    fEnable [integer!]
] lib "Mp3_ReverseMode"

Mp3_Close: make routine! [
    return: [integer!] 
    initialized [integer!]
] lib "Mp3_Close"

waves: []
foreach file read %. [
    if (%.mp3 = suffix? file) [append waves file]
]
append waves "(CHANGE FOLDER...)"

initialized: Mp3_Initialize

view center-face layout [
    vh2 "Click a File to Play:"
    file-list: text-list data waves [
        if value = "(CHANGE FOLDER...)" [
            new-dir: request-dir
            if new-dir = none [break]
            change-dir new-dir        
            waves: copy []
            foreach file read %. [
                if (%.mp3 = suffix? file) [append waves file]
            ]
            append waves "(CHANGE FOLDER...)"
            file-list/data: waves
            show file-list
            break
        ]
        Mp3_GetStatus initialized status
        if (status/fPlay = 0) [
            file: rejoin [to-local-file what-dir "\" value]
            Mp3_OpenFile initialized file 1000 0 0
            Mp3_Play initialized
        ]
    ]
    across
    tabs 40
    text "Seek:   " 
    tab slider 140x15 [
        plength: make struct! Mp3_Time compose [0 0 0 0 0 0 0 0]
        Mp3_GetSongLength initialized plength
        location: to-integer (value * plength/sec)
        ptime: make struct! Mp3_Time compose [0 (location) 0 0 0 0 0 0]
        Mp3_Seek initialized TIME_FORMAT_SEC ptime SONG_BEGIN
        Mp3_Play initialized
    ]
    return
    text "Volume: " 
    tab slider 140x15 [
        volume: to-integer value * 100
        Mp3_SetVolume initialized volume volume
    ]
    return
    btn 58 "Stop" [
         if (attempt [sound-port]) [
             close sound-port
             wait-flag: false
         ]
         if (status/fPlay > 0) [Mp3_Stop initialized]
    ]
    btn "Reverse" [
        Mp3_GetStatus initialized status
        either (status/fReverse > 0) [
            Mp3_ReverseMode initialized 0
        ] [
            Mp3_ReverseMode initialized 1
        ]
    ]
    btn "Vocal-Cut" [
        Mp3_GetStatus initialized status
        either (status/fVocalCut > 0) [
            Mp3_VocalCut initialized 0
        ] [
            Mp3_VocalCut initialized 1
        ]
    ]
]

Mp3_Destroy initialized
free lib