let filename = exec_args[1]

const FBUF_SIZE = 560*448
const MAGIC = [0x1F, 0x54, 0x53, 0x56, 0x4D, 0x4D, 0x4F, 0x56]
const port = filesystem._toPorts("A")[0]

println("Reading...")

com.sendMessage(port, "DEVRST\x17")
com.sendMessage(port, `OPENR"${filename}",1`)
let statusCode = com.getStatusCode(port)

if (statusCode != 0) return statusCode

//let bytes = filesystem.readAllBytes("A")

//con.clear()

let readCount = 0

function readBytes(length) {
    /*let ret = new Int8Array(length)
    for (let k = 0; k < length; k++) {
        ret[k] = bytes[readCount]
        readCount += 1
    }
    return ret*/

    let ptr = sys.malloc(length)
    let requiredBlocks = Math.floor((readCount + length) / 4096) - Math.floor(readCount / 4096)

    let completedReads = 0

    serial.println(`readBytes(${length}); readCount = ${readCount}`)

    for (let bc = 0; bc < requiredBlocks + 1; bc++) {
        if (completedReads >= length) break

        if (readCount % 4096 == 0) {
            serial.println("READ from serial")
            com.sendMessage(port, "READ")
            statusCode = com.getStatusCode(port)
            if (statusCode != 0) {
                printerrln("READ failed with "+statusCode)
                return statusCode
            }
            // pull the actual message
            sys.poke(-4093 - port, 6);sys.sleep(0) // spinning is required as Graal run is desynced with the Java side

            // FIXME READ won't fetch next block!


            let blockTransferStatus = ((sys.peek(-4085 - port*2) & 255) | ((sys.peek(-4086 - port*2) & 255) << 8))
            let thisBlockLen = blockTransferStatus & 4095
            if (thisBlockLen == 0) thisBlockLen = 4096 // [1, 4096]
            let hasMore = (blockTransferStatus & 0x8000 != 0)


            serial.println(`block: (${thisBlockLen})[${[...Array(thisBlockLen).keys()].map(k => (sys.peek(-4097 - k) & 255).toString(16).padStart(2,'0')).join()}]`)

            let remaining = Math.min(thisBlockLen, length - completedReads)

            serial.println(`Pulled a block (${thisBlockLen}); readCount = ${readCount}, completedReads = ${completedReads}, remaining = ${remaining}`)

            // copy from read buffer to designated position
            sys.memcpy(-4097, ptr + completedReads, remaining)

            // increment readCount properly
            readCount += remaining
            completedReads += remaining
        }
        else {
            let padding = readCount % 4096
            let remaining = length - completedReads
            let thisBlockLen = Math.min(4096 - padding, length - completedReads)

            serial.println(`padding = ${padding}; remaining = ${remaining}`)

            serial.println(`block: (${thisBlockLen})[${[...Array(thisBlockLen).keys()].map(k => (sys.peek(-4097 - padding - k) & 255).toString(16).padStart(2,'0')).join()}]`)

            serial.println(`Reusing a block (${thisBlockLen}); readCount = ${readCount}, completedReads = ${completedReads}`)

            // copy from read buffer to designated position
            sys.memcpy(-4097 - padding, ptr + completedReads, thisBlockLen)

            // increment readCount properly
            readCount += thisBlockLen
            completedReads += thisBlockLen
        }
    }

    serial.println(`END readBytes(${length}); readCount = ${readCount}\n`)

    return ptr
}

function readInt() {
    let b = readBytes(4)
    let i = (sys.peek(b) & 255) | ((sys.peek(b+1) & 255) << 8) | ((sys.peek(b+2) & 255) << 16) | ((sys.peek(b+3) & 255) << 24)

    serial.println(`readInt(); bytes: ${sys.peek(b)}, ${sys.peek(b+1)}, ${sys.peek(b+2)}, ${sys.peek(b+3)} = ${i}\n`)

    sys.free(b)
    return i
}

function readShort() {
    let b = readBytes(2)
    let i = (sys.peek(b) & 255) | ((sys.peek(b+1) & 255) << 8)

    serial.println(`readShort(); bytes: ${sys.peek(b)}, ${sys.peek(b+1)} = ${i}\n`)

    sys.free(b)
    return i
}


let magic = readBytes(8)
let magicMatching = true

// check if magic number matches
MAGIC.forEach((b,i) => {
    let testb = sys.peek(magic + i) & 255 // for some reason this must be located here
    if (testb != b) {
        magicMatching = false
    }
})
sys.free(magic)
if (!magicMatching) {
    println("Not a movie file (MAGIC mismatch)")
    return 1
}


let width = readShort()
let height = readShort()
let fps = readShort()
let frameCount = readInt() % 16777216

serial.println(readCount) // must say 18
serial.println(`Dim: (${width}x${height}), FPS: ${fps}, Frames: ${frameCount}`)

let fbuf = sys.malloc(FBUF_SIZE)

for (let f = 0; f < frameCount; f++) {
    serial.println(`Frame #${f+1}`)

    let payloadLen = readInt()
    let gzippedPtr = readBytes(payloadLen)

    gzip.decompFromTo(gzippedPtr, payloadLen, fbuf) // should return FBUF_SIZE

    dma.ramToFrame(fbuf, 0, FBUF_SIZE)
    sys.free(gzippedPtr)
}

sys.free(fbuf)