package path

import (
	"fmt"

	"github.com/Tnze/go-mc/bot/world"
	"github.com/Tnze/go-mc/data/block"
)

// Cardinal directions.
type Direction uint8

func (d Direction) Offset() (x, y, z int) {
	switch d {
	case North:
		return 0, 0, -1
	case South:
		return 0, 0, 1
	case East:
		return 1, 0, 0
	case West:
		return -1, 0, 0
	}
	panic(fmt.Sprintf("unknown direction value: %v", d))
}

func (d Direction) Offset2x() (x, y, z int) {
	x, y, z = d.Offset()
	return x + x, y + y, z + z
}

func (d Direction) String() string {
	switch d {
	case North:
		return "north"
	case South:
		return "south"
	case East:
		return "east"
	case West:
		return "west"
	}
	return fmt.Sprintf("Direction?<%d>", int(d))
}

// Valid direction values.
const (
	North Direction = iota
	South
	West
	East
)

func LadderDirection(bStateID world.BlockStatus) Direction {
	return Direction(((uint32(bStateID) - block.Ladder.MinStateID) & 0xE) >> 1)
}

func ChestDirection(bStateID world.BlockStatus) Direction {
	return Direction(((uint32(bStateID) - block.Chest.MinStateID) / 6) & 0x3)
}

func StairsDirection(bStateID world.BlockStatus) Direction {
	b := block.StateID[uint32(bStateID)]
	return Direction(((uint32(bStateID) - block.ByID[b].MinStateID) / 20) & 0x3)
}

func SlabIsBottom(bStateID world.BlockStatus) bool {
	b := block.StateID[uint32(bStateID)]
	return ((uint32(bStateID)-block.ByID[b].MinStateID)&0xE)>>1 == 1
}

// Movement represents a single type of movement in a path.
type Movement uint8

var allMovements = []Movement{TraverseNorth, TraverseSouth, TraverseEast, TraverseWest,
	TraverseNorthWest, TraverseNorthEast, TraverseSouthWest, TraverseSouthEast,
	DropNorth, DropSouth, DropEast, DropWest,
	Drop2North, Drop2South, Drop2East, Drop2West,
	AscendNorth, AscendSouth, AscendEast, AscendWest,
	DescendLadder, DescendLadderNorth, DescendLadderSouth, DescendLadderEast, DescendLadderWest,
	AscendLadder,
	JumpCrossNorth, JumpCrossSouth, JumpCrossEast, JumpCrossWest,
}

// Valid movement values.
const (
	Waypoint Movement = iota
	TraverseNorth
	TraverseSouth
	TraverseEast
	TraverseWest
	TraverseNorthEast
	TraverseNorthWest
	TraverseSouthEast
	TraverseSouthWest
	DropNorth
	DropSouth
	DropEast
	DropWest
	Drop2North
	Drop2South
	Drop2East
	Drop2West
	AscendNorth
	AscendSouth
	AscendEast
	AscendWest
	DescendLadder
	DescendLadderNorth
	DescendLadderSouth
	DescendLadderEast
	DescendLadderWest
	AscendLadder
	JumpCrossEast
	JumpCrossWest
	JumpCrossNorth
	JumpCrossSouth
)

func (m Movement) Possible(nav *Nav, x, y, z int, from V3, previous Movement) bool {
	switch m {
	case Waypoint, TraverseNorth, TraverseSouth, TraverseEast, TraverseWest:
		if !SteppableBlock(nav.World.GetBlockStatus(x, y, z)) {
			return false
		}
		b1, b2 := nav.World.GetBlockStatus(x, y+1, z), nav.World.GetBlockStatus(x, y+2, z)
		u1, u2 := AirLikeBlock(b1) || IsLadder(b1), AirLikeBlock(b2) || IsLadder(b2)
		return u1 && u2

	case TraverseNorthWest, TraverseNorthEast, TraverseSouthWest, TraverseSouthEast:
		if !SteppableBlock(nav.World.GetBlockStatus(x, y, z)) {
			return false
		}
		if !AirLikeBlock(nav.World.GetBlockStatus(x, y+1, z)) || !AirLikeBlock(nav.World.GetBlockStatus(x, y+2, z)) {
			return false
		}
		if !AirLikeBlock(nav.World.GetBlockStatus(from.X, y+1, z)) || !AirLikeBlock(nav.World.GetBlockStatus(from.X, y+2, z)) {
			return false
		}
		return AirLikeBlock(nav.World.GetBlockStatus(x, y+1, from.Z)) && AirLikeBlock(nav.World.GetBlockStatus(x, y+2, from.Z))

	case Drop2North, Drop2South, Drop2East, Drop2West:
		if !AirLikeBlock(nav.World.GetBlockStatus(x, y+4, z)) {
			return false
		}
		fallthrough

	case DropNorth, DropSouth, DropEast, DropWest:
		for amt := 0; amt < 3; amt++ {
			if !AirLikeBlock(nav.World.GetBlockStatus(x, y+amt+1, z)) {
				return false
			}
		}
		return SteppableBlock(nav.World.GetBlockStatus(x, y, z))

	case AscendNorth, AscendSouth, AscendEast, AscendWest:
		if !AirLikeBlock(nav.World.GetBlockStatus(x, y+1, z)) || !AirLikeBlock(nav.World.GetBlockStatus(x, y+2, z)) {
			return false
		}
		return SteppableBlock(nav.World.GetBlockStatus(x, y, z)) &&
			AirLikeBlock(nav.World.GetBlockStatus(from.X, from.Y+1, from.Z)) &&
			AirLikeBlock(nav.World.GetBlockStatus(from.X, from.Y+2, from.Z))

	case DescendLadder, AscendLadder:
		if bID := nav.World.GetBlockStatus(x, y+1, z); !AirLikeBlock(bID) && !IsLadder(bID) {
			return false
		}
		return IsLadder(nav.World.GetBlockStatus(x, y, z))

	case DescendLadderNorth, DescendLadderSouth, DescendLadderEast, DescendLadderWest:
		for amt := 0; amt < 2; amt++ {
			if bID := nav.World.GetBlockStatus(x, y+amt+1, z); !AirLikeBlock(bID) && !IsLadder(bID) {
				return false
			}
		}
		return IsLadder(nav.World.GetBlockStatus(x, y, z))

	case JumpCrossEast, JumpCrossWest, JumpCrossNorth, JumpCrossSouth:
		if !AirLikeBlock(nav.World.GetBlockStatus(x, y+1, z)) || !AirLikeBlock(nav.World.GetBlockStatus(x, y+2, z)) || !AirLikeBlock(nav.World.GetBlockStatus(x, y+3, z)) {
			return false
		}
		midX, midZ := (from.X+x)/2, (from.Z+z)/2
		if !AirLikeBlock(nav.World.GetBlockStatus(midX, y+1, midZ)) || !AirLikeBlock(nav.World.GetBlockStatus(midX, y+2, midZ)) || !AirLikeBlock(nav.World.GetBlockStatus(midX, y+3, midZ)) {
			return false
		}
		if !AirLikeBlock(nav.World.GetBlockStatus(from.X, from.Y+3, from.Z)) {
			return false
		}
		return SteppableBlock(nav.World.GetBlockStatus(x, y, z))

	default:
		panic(m)
	}
}

func (m Movement) Offset() (x, y, z int) {
	switch m {
	case Waypoint:
		return 0, 0, 0
	case TraverseNorth:
		return North.Offset()
	case TraverseSouth:
		return South.Offset()
	case TraverseEast:
		return East.Offset()
	case TraverseWest:
		return West.Offset()

	case JumpCrossEast:
		return East.Offset2x()
	case JumpCrossWest:
		return West.Offset2x()
	case JumpCrossNorth:
		return North.Offset2x()
	case JumpCrossSouth:
		return South.Offset2x()

	case AscendLadder:
		return 0, 1, 0
	case DescendLadder:
		return 0, -1, 0
	case DropNorth, DescendLadderNorth:
		return 0, -1, -1
	case DropSouth, DescendLadderSouth:
		return 0, -1, 1
	case DropEast, DescendLadderEast:
		return 1, -1, 0
	case DropWest, DescendLadderWest:
		return -1, -1, 0
	case AscendNorth:
		return 0, 1, -1
	case AscendSouth:
		return 0, 1, 1
	case AscendEast:
		return 1, 1, 0
	case AscendWest:
		return -1, 1, 0

	case TraverseNorthWest:
		return -1, 0, -1
	case TraverseNorthEast:
		return 1, 0, -1
	case TraverseSouthWest:
		return -1, 0, 1
	case TraverseSouthEast:
		return 1, 0, 1

	case Drop2North:
		return 0, -2, -1
	case Drop2South:
		return 0, -2, 1
	case Drop2East:
		return 1, -2, 0
	case Drop2West:
		return -1, -2, 0

	default:
		panic(m)
	}
}

func (m Movement) BaseCost() float64 {
	switch m {
	case Waypoint:
		return 0
	case TraverseNorth, TraverseSouth, TraverseEast, TraverseWest:
		return 2
	case TraverseNorthWest, TraverseNorthEast, TraverseSouthWest, TraverseSouthEast:
		return 2.5

	case DropNorth, DropSouth, DropEast, DropWest, Drop2North, Drop2South, Drop2East, Drop2West:
		return 4
	case AscendNorth, AscendSouth, AscendEast, AscendWest:
		return 4
	case DescendLadderNorth, DescendLadderSouth, DescendLadderEast, DescendLadderWest:
		return 1.5
	case DescendLadder:
		return 1
	case AscendLadder:
		return 3

	case JumpCrossEast, JumpCrossWest, JumpCrossNorth, JumpCrossSouth:
		return 5.5
	default:
		panic(m)
	}
}

func (m Movement) String() string {
	switch m {
	case Waypoint:
		return "waypoint"
	case TraverseNorth:
		return "traverse-north"
	case TraverseSouth:
		return "traverse-south"
	case TraverseEast:
		return "traverse-east"
	case TraverseWest:
		return "traverse-west"

	case DropNorth:
		return "drop-north"
	case DropSouth:
		return "drop-south"
	case DropEast:
		return "drop-east"
	case DropWest:
		return "drop-west"
	case Drop2North:
		return "drop-2-north"
	case Drop2South:
		return "drop-2-south"
	case Drop2East:
		return "drop-2-east"
	case Drop2West:
		return "drop-2-west"

	case AscendNorth:
		return "jump-north"
	case AscendSouth:
		return "jump-south"
	case AscendEast:
		return "jump-east"
	case AscendWest:
		return "jump-west"

	case TraverseNorthWest:
		return "traverse-northwest"
	case TraverseNorthEast:
		return "traverse-northeast"
	case TraverseSouthWest:
		return "traverse-southwest"
	case TraverseSouthEast:
		return "traverse-southeast"

	case DescendLadder:
		return "descend-ladder"
	case DescendLadderNorth:
		return "descend-ladder-north"
	case DescendLadderSouth:
		return "descend-ladder-south"
	case DescendLadderEast:
		return "descend-ladder-east"
	case DescendLadderWest:
		return "descend-ladder-west"

	case AscendLadder:
		return "ascend-ladder"

	case JumpCrossEast:
		return "jump-crossing-east"
	case JumpCrossWest:
		return "jump-crossing-west"
	case JumpCrossNorth:
		return "jump-crossing-north"
	case JumpCrossSouth:
		return "jump-crossing-south"
	default:
		panic(m)
	}
}