package merkle

import (
    . "github.com/tendermint/tendermint/binary"
    "os"
    "fmt"
    "crypto/sha256"
)

/*
Compute a deterministic merkle hash from a list of byteslices.
*/
func HashFromBinarySlice(items []Binary) ByteSlice {
    switch len(items) {
    case 0:
        panic("Cannot compute hash of empty slice")
    case 1:
        hasher := sha256.New()
        _, err := items[0].WriteTo(hasher)
        if err != nil { panic(err) }
        return ByteSlice(hasher.Sum(nil))
    default:
        hasher := sha256.New()
        _, err := HashFromBinarySlice(items[0:len(items)/2]).WriteTo(hasher)
        if err != nil { panic(err) }
        _, err = HashFromBinarySlice(items[len(items)/2:]).WriteTo(hasher)
        if err != nil { panic(err) }
        return ByteSlice(hasher.Sum(nil))
    }
}

func PrintIAVLNode(node *IAVLNode) {
    fmt.Println("==== NODE")
    if node != nil {
        printIAVLNode(node, 0)
    }
    fmt.Println("==== END")
}

func printIAVLNode(node *IAVLNode, indent int) {
    indentPrefix := ""
    for i:=0; i<indent; i++ {
        indentPrefix += "    "
    }

    if node.right != nil {
        printIAVLNode(node.rightFilled(nil), indent+1)
    }

    fmt.Printf("%s%v:%v\n", indentPrefix, node.key, node.height)

    if node.left != nil {
        printIAVLNode(node.leftFilled(nil), indent+1)
    }

}

func randstr(length int) String {
    if urandom, err := os.Open("/dev/urandom"); err != nil {
        panic(err)
    } else {
        slice := make([]byte, length)
        if _, err := urandom.Read(slice); err != nil {
            panic(err)
        }
        urandom.Close()
        return String(slice)
    }
    panic("unreachable")
}

func maxUint8(a, b uint8) uint8 {
    if a > b {
        return a
    }
    return b
}