-- 'Hole' program, version 1.1
-- Created by Pyro_
-- Credit:
--      theoriginalbit
-- Also:
--      BigSHinyToys
--      BombMan

local version = 1.1

-- Stores data about current mode
local speedy = false
local noFuel = false
local fuelChest = false

-- Stores turtle status data
local isRefuelling = false
local fuelLevel = 0

-- Stores dimensions for the hole
local sizeX, sizeZ, depth = 0,0,0

-- Stores current turtle position, relative to start point
local xPos, yPos, zPos = 0,0,0


-- Stores current direction, positive x is directly forwards from start point
-- positive z is directly right
local xDir, zDir = 1,0

-- Stores last saved position (Save 1)
local xSav1, ySav1, zSav1 = 0,0,0
local xDirSav1, zDirSav1 = 0,0
local save1Mutex = 0

-- Save 2
local xSav2, ySav2, zSav2 = 0,0,0
local xDirSav2, zDirSav2 = 0,0
local save2Mutex = 0

-- This is required in movement functions
-- Calculates distance to home, with small buffer
local function distToHome()
    local distance
    -- Y is negative because the y axis increases as it goes up
    distance = xPos + (-yPos) + zPos + 5
    return distance
end

-- **************************************************
-- Movement / Turning functions
local function moveForwardRF()
    local retVal = true
    -- Account for falling blocks, such as sand and gravel
    if not speedy then
        while turtle.detect() do
            turtle.dig()
            sleep(0.8)
        end
    else
        turtle.dig()
    end
    -- If there is any mob infront of the turtle, or we are out of fuel
    -- DEV NOTE: Will be modified later to refuel, or message over rednet wifi
    while not turtle.forward() do
        turtle.attack()
    end

    -- Update position
    xPos = xPos + xDir
    zPos = zPos + zDir

    if not noFuel then
        -- Update fuel info
        fuelLevel = fuelLevel - 1

        -- Fuel checking
        if (distToHome() >= fuelLevel) and not isRefuelling then
            retVal = false
        end
    end

    return retVal
end

local function moveUpRF()
    local retVal = true
    -- Account for falling blocks
    if not speedy then
        while turtle.detectUp() do
            turtle.digUp()
            sleep(0.8)
        end
    else
        turtle.digUp()
    end
    --Update position
    yPos = yPos + 1

    while not turtle.up() do
        turtle.attackUp()
    end

    if not noFuel then
        -- Update fuel info
        fuelLevel = fuelLevel - 1

        -- Fuel checking
        if (distToHome() >= fuelLevel) and not isRefuelling then
            retVal = false
        end
    end

    return retVal
end

local function moveDownRF()
    local retVal = true
    -- No need to account for falling blocks
    turtle.digDown()

    -- Update position
    yPos = yPos - 1

    while not turtle.down() do
        turtle.attackDown()
    end

    if not noFuel then
        -- Update fuel info
        fuelLevel = fuelLevel - 1

        -- Fuel checking (skip if already refuelling)
        if (distToHome() >= fuelLevel) and not isRefuelling then
            retVal = false
        end
    end

    return retVal
end

-- Move functions, with fuel checking (will be ignored if noFuel mode is selected)
local function moveForward()
    if not moveForwardRF() then
        refuel()
    end
end

local function moveUp()
    if not moveUpRF() then
        refuel()
    end
end

local function moveDown()
    if not moveDownRF() then
        refuel()
    end
end

local function turnLeft()
    -- Update direction vector
    zDir, xDir = -xDir, zDir

    turtle.turnLeft()
end

local function turnRight()
    -- Update direction vector
    zDir, xDir = xDir, -zDir

    turtle.turnRight()
end

local function turnAround()
    -- Update direction
    zDir, xDir = -zDir, -xDir

    turtle.turnLeft()
    turtle.turnLeft()
end

-- Turns the turtle to the prompted direction
local function turnToDir(x, z)
    if x == 1 and xDir == 0 then
        if zDir == 1 then
            turnLeft()
        else
            turnRight()
        end
    elseif x == 1 and xDir == -1 then
        turnAround()
    elseif x == -1 and xDir == 0 then
        if zDir == 1 then
            turnRight()
        else
            turnLeft()
        end
    elseif x == -1 and xDir == 1 then
        turnAround()
    elseif z == 1 and zDir == 0 then
        if xDir == 1 then
            turnRight()
        else
            turnLeft()
        end
    elseif z == 1 and zDir == -1 then
        turnAround()
    elseif z == -1 and zDir == 0 then
        if xDir == 1 then
            turnLeft()
        else
            turnRight()
        end
    elseif z == -1 and zDir == 1 then
        turnAround()
    else
        return false
    end
    return true
end

-- Takes in a coordinate and moves the turtle there
-- IMPLEMENTATION NOTE: Turtle will be facing in whatever direction it finishes in.
--                      Keep this in mind, as it might affect what happens next.
local function moveToPos(x, y, z)

    -- Move the turtle to the required X value
        if x > xPos then
            turnToDir(1, 0)
            while x > xPos do
                moveForward()
            end
        elseif x < xPos then
            turnToDir(-1, 0)
            while x < xPos do
                moveForward()
            end
        end

    -- Move the turtle to the required Z value
        if z > zPos then
            turnToDir(0, 1)
            while z > zPos do
                moveForward()
            end
        elseif z < zPos then
            turnToDir(0, -1)
            while z < zPos do
                moveForward()
            end
        end

    -- Move the turtle to the required Y value
        if y > yPos then
            while y > yPos do
                moveUp()
            end
        else
            while y < yPos do
                moveDown()
            end
        end
end

-- End of movement functions
-- **************************************************

-- ++++++++++++++++++++++++++++++++++++++++++++++++++
-- Logic functions

-- Saves the current dig position and direction
local function saveDig()
    local retVal = 0
    if save1Mutex == 0 then
        xSav1 = xPos
        ySav1 = yPos
        zSav1 = zPos
        xDirSav1 = xDir
        zDirSav1 = zDir
        save1Mutex = 1
        retVal = 1
    elseif save2Mutex == 0 then
        xSav2 = xPos
        ySav2 = yPos
        zSav2 = zPos
        xDirSav2 = xDir
        zDirSav2 = zDir
        save2Mutex = 1
        retVal = 2
    end
    return retVal
end

-- Dumps the load into a chest or thin air
local function dumpLoad()
    for n = 1, 16 do
        turtle.select(n)
        turtle.drop()
    end
end


-- Moves the turtle back to the last saved position and direction
local function resumeDig(save)
    if save == 1 then
        moveToPos(xSav1, ySav1, zSav1)
        turnToDir(xDirSav1, zDirSav1)
        save1Mutex = 0
    elseif save == 2 then
        moveToPos(xSav2, ySav2, zSav2)
        turnToDir(xDirSav2, xDirSav2)
        save2Mutex = 0
    end
end

-- Move the turtle to the home and fuel chests, dump load and refuel, then
-- resume digging
function refuel()
print("refuelling")
    local save

    isRefuelling = 1

    save = saveDig()
    moveToPos(0, 0, 0)
    turnToDir(-1, 0)
    dumpLoad()
    turnToDir(0, -1)
    turtle.select(1)
    turtle.suck()
    turtle.refuel()

    fuelLevel = turtle.getFuelLevel()

    resumeDig(save)

    isRefuelling = 0
end


-- Simply checks if the turtle is full
-- DEV NOTE: this is kind of brute-forcish, I wonder if there's a better way?
local function isFull()
    local retVal = true
    for n = 1, 16 do
        if turtle.getItemCount(n) == 0 then
            retVal = false
        end
    end
    return retVal
end

-- Digs the current strip in the current layer (parallel to X axis)
local function digStrip()
    for i = 2, sizeX do
        moveForward()
        if isFull() then
            local save
            save = saveDig()
            moveToPos(0,0,0)
            turnToDir(-1, 0)
            dumpLoad()
            resumeDig(save)
        end
    end
end

-- Turns the turtle in the correct direction at the end of digging a strip
local function stripTurn(strips)
-- This is a bit bizzarre, since when we have an odd number of strips,
-- then the turns are the same for every level, but when we have an
-- even number of strips, they flip every other level
    if strips ~= sizeZ - 1 and sizeZ % 2 == 1 then
        if strips % 2 == 1 then
            turnLeft()
            moveForward()
            turnLeft()
        else
            turnRight()
            moveForward()
            turnRight()
        end
-- DEV NOTE: is there a better way of doing this?
    elseif strips ~= sizeZ -1 and sizeZ % 2 == 0 then
        if yPos % 2 == 0 and strips % 2 == 0 then
            turnRight()
            moveForward()
            turnRight()
        elseif yPos % 2 == 1 and strips % 2 == 1 then
            turnRight()
            moveForward()
            turnRight()
        else
            turnLeft()
            moveForward()
            turnLeft()
        end
    end
end

-- Digs the current layer
local function digLayer()
    local strips = 0
    print("Beginning layer: "..(-yPos))
    for i = 1, sizeZ do
        digStrip()
        stripTurn(strips)
        strips = strips + 1
    end
end


-- This function controls the digging of the hole
local function digOut()
-- This for loop controls how many layers we are going to dig
    for n = 1, depth do
        digLayer()
        -- If this was no the last layer, then start digging the next one, otherwise,
        -- head home and empty contents into the chest
        if n ~= depth then
            turnAround()
            moveDown()
        elseif n == depth then
            moveToPos(0, 0, 0)
            turnToDir(-1, 0)
            dumpLoad()
            turnToDir(1, 0)
        end
    end
end

-- Converts the dimension arguments to numbers
local function argToNumber(argv)
    argv[1] = tonumber(argv[1])
    argv[2] = tonumber(argv[2])
    argv[3] = tonumber(argv[3])
end

-- Validate the dimensions passed to the program (so the first three arguments)
local function validateDimensions(argv)
    local retVal = true
    -- Convert the flags to usable numbers
    argToNumber(argv)
    -- Check that they exist, and are numbers
    if argv[1] == nil or not type(argv[1], "number") then
        retVal = false
    elseif argv[2] == nil or not type(argv[2], "number") then
        retVal = false
    elseif argv[3] == nil or not type(argv[3], "number") then
        retVal = false
    -- Check that the numbers are valid
    elseif argv[1] < 0 then
        retVal = false
    elseif argv[2] < 0 then
        retVal = false
    elseif argv[3] < 0 then
        retVal = false
    end
    return retVal
end

-- Will validate the flags (if any) that were passed to the program
-- They are also set here, as it turns out to be easier
local function validateAndParseFlags(argc, argv)
    local retVal = true
    if not type(argv[4], "string") or not argv[4] then
        retVal = false
    elseif not type(argv[5], "string") or not argv[4] then
        retVal = false
    else
        for i = 4, argc do
            if argv[i] == "-s" then
                speedy = true
                print("Speed mode")
            elseif argv[i] == "-fc" then
                fuelChest = true
                print("Fuel chest mode")
            else
                retVal = false
            end
        end
    end
    return retVal
end

-- Prints usage information to the terminal
local function printUsage()
    term.clear()
    term.setCursorPos(1, 1)
    print("Usage:")
    print("hole [<size X> <size Z> <depth> -s -fc] | help")
    print("")
    print("-s : speed mode")
    print("-fc : fuel chest mode")
    print("")
    print("Using 'hole help' will display help pages")
end

-- Just prints author info
local function printInfo()
    print("Created by: Pyro_")
    print("Credit to: theoriginalbit, BigSHinyToys and BombMan")
end

-- Just writes help information to the terminal, one of these
-- days I will have it write a help file for the help program,
-- then call the help program or something
local function printHelp()
    term.clear()
    term.setCursorPos(1, 2)
    print("Information:")
    print("An ongoing development project by Pyro_")
    print("Credit to:")
    print("theoriginalbit, BigSHinyToys and BombMan")
    print("Come check us out on the CC forums")
    print("")
    print("Version: ".. version)
    print("OS Version: " .. os.version())
    -- Keep page number and any key prompt in the same spot
    -- this way they don't interfere with spacing
    term.setCursorPos(x - string.len("Page 1"), 12)
    print("Page 1")
    term.setCursorPos(1, 13)
    print("Press any key to continue")
    os.pullEvent("key")
    term.clear()
    term.setCursorPos(1, 2)
    -- Why not?
    printUsage()
    term.setCursorPos(x - string.len("Page 2"), 12)
    print("Page 2")
    term.setCursorPos(1, 13)
    print("Press any key to continue")
    os.pullEvent("key")
    term.clear()
    term.setCursorPos(1, 2)
    print("All flags with '-' preceding them are optional")
    print("All flags surrounded by '<>' are required")
    print("")
    print("Using -s will skip checking for blocks that may fall in front of the turtle,")
    print("so ensure this won't happen before you use this flag")
    term.setCursorPos(x - string.len("Page 3"), 12)
    print("Page 3")
    term.setCursorPos(1, 13)
    print("Press any key to continue")
    os.pullEvent("key")
    term.clear()
    term.setCursorPos(1, 2)
    print("Using -fc will tell the turtle that")
    print("there's a chest of fuel located to it's")
    print("immediate left when it initially starts")
    print("it will use the fuel inside the chest")
    print("to refuel when it gets low")
    print("")
    print("Note: The turtle will pull one whole")
    print("stack from a slot in the chest, so")
    print("budget fuel accordingly; so that it")
    print("doesn't end up eating fuel it will")
    print("never use...")
    term.setCursorPos(x - string.len("Page 4"), 12)
    print("Page 4")
    term.setCursorPos(1, 13)
    print("Press any key to return")
    os.pullEvent("key")
    term.clear()
    term.setCursorPos(1, 1)
end

-- Checks if the user has requested the help page
local function isFlagHelp(argv)
    local retVal = false
    if argv[1] == "help" then
        retVal = true
    end
    return retVal
end

-- End of logic functions
-- ++++++++++++++++++++++++++++++++++++++++++++++++++

-- Main function controls flow of program
local function main(argc, argv)

    if isFlagHelp(argv) then
        printHelp()
    elseif not validateDimensions(argv) then
        printUsage()
        printInfo()
    elseif not validateAndParseFlags(argc, argv) then
    -- Test if the 'speedy' or 'fuel chest' flags were set
        printUsage()
        printInfo()
    else

        -- If we aren't in fuel chest mode, then ignore fuel checking
        if fuelChest == false then
            noFuel = true
        end
        -- Backwards compatability; think C ternary operation
        -- fuelLevel will be ignored if noFuel flag is set
        fuelLevel = turtle.getFuelLevel and turtle.getFuelLevel() or "unlimited"

        -- Will skip fuel checking if turtleNeedsFuel is 0 in config
        if fuelLevel == "unlimited" then
            noFuel = true
        end

        sizeX = argv[1]
        sizeZ = argv[2]
        depth = argv[3]

        local dims = string.format("Dimensions: X: %i Z: %i Depth: %i", sizeX, sizeZ, depth)

        print("Beginning dig...")
        print(dims)
        digOut()
        print("Finished dig...")
    end
end

main(#{...}, {...})