package d2render

import (
	"fmt"
	"image"
	"log"
	"math"
	"math/rand"
	"strings"

	"github.com/OpenDiablo2/D2Shared/d2common/d2enum"
	"github.com/OpenDiablo2/D2Shared/d2common/d2interface"
	"github.com/OpenDiablo2/D2Shared/d2data"
	"github.com/OpenDiablo2/D2Shared/d2data/d2cof"
	"github.com/OpenDiablo2/D2Shared/d2data/d2datadict"
	"github.com/OpenDiablo2/D2Shared/d2data/d2dcc"
	"github.com/OpenDiablo2/D2Shared/d2helper"
	"github.com/hajimehoshi/ebiten"
)

var DccLayerNames = []string{"HD", "TR", "LG", "RA", "LA", "RH", "LH", "SH", "S1", "S2", "S3", "S4", "S5", "S6", "S7", "S8"}

type LayerCacheEntry struct {
	frameSheet       *ebiten.Image
	frameWidth       int
	frameHeight      int
	compositeMode    ebiten.CompositeMode
	offsetX, offsetY int32
}

// AnimatedEntity represents an entity on the map that can be animated
type AnimatedEntity struct {
	fileProvider       d2interface.FileProvider
	LocationX          float64
	LocationY          float64
	TileX, TileY       int     // Coordinates of the tile the unit is within
	subcellX, subcellY float64 // Subcell coordinates within the current tile
	dccLayers          map[string]d2dcc.DCC
	Cof                *d2cof.COF
	palette            d2enum.PaletteType
	base               string
	token              string
	animationMode      string
	weaponClass        string
	lastFrameTime      float64
	framesToAnimate    int
	animationSpeed     float64
	direction          int
	currentFrame       int
	offsetX, offsetY   int32
	object             *d2datadict.ObjectLookupRecord
	layerCache         []LayerCacheEntry
	drawOrder          [][]d2enum.CompositeType
	TargetX            float64
	TargetY            float64
	action             int32
	repetitions        int32
}

// CreateAnimatedEntity creates an instance of AnimatedEntity
func CreateAnimatedEntity(x, y int32, object *d2datadict.ObjectLookupRecord, fileProvider d2interface.FileProvider, palette d2enum.PaletteType) AnimatedEntity {
	result := AnimatedEntity{
		fileProvider: fileProvider,
		base:         object.Base,
		token:        object.Token,
		object:       object,
		palette:      palette,
		layerCache:   make([]LayerCacheEntry, d2enum.CompositeTypeMax),
	}
	result.dccLayers = make(map[string]d2dcc.DCC)
	result.LocationX = float64(x)
	result.LocationY = float64(y)
	result.TargetX = result.LocationX
	result.TargetY = result.LocationY

	result.TileX = int(result.LocationX / 5)
	result.TileY = int(result.LocationY / 5)
	result.subcellX = 1 + math.Mod(result.LocationX, 5)
	result.subcellY = 1 + math.Mod(result.LocationY, 5)

	return result
}

// SetMode changes the graphical mode of this animated entity
func (v *AnimatedEntity) SetMode(animationMode, weaponClass string, direction int) {
	cofPath := fmt.Sprintf("%s/%s/COF/%s%s%s.COF", v.base, v.token, v.token, animationMode, weaponClass)
	v.Cof = d2cof.LoadCOF(cofPath, v.fileProvider)
	if v.Cof.NumberOfDirections == 0 || v.Cof.NumberOfLayers == 0 || v.Cof.FramesPerDirection == 0 {
		return
	}
	resetAnimation := v.animationMode != animationMode || v.weaponClass != weaponClass
	v.animationMode = animationMode
	v.weaponClass = weaponClass
	v.direction = direction
	if v.direction >= v.Cof.NumberOfDirections {
		v.direction = v.Cof.NumberOfDirections - 1
	}
	v.dccLayers = make(map[string]d2dcc.DCC)
	for _, cofLayer := range v.Cof.CofLayers {
		layerName := DccLayerNames[cofLayer.Type]
		v.dccLayers[layerName] = v.LoadLayer(layerName, v.fileProvider)
		if !v.dccLayers[layerName].IsValid() {
			continue
		}
	}

	v.updateFrameCache(resetAnimation)
}

func (v *AnimatedEntity) LoadLayer(layer string, fileProvider d2interface.FileProvider) d2dcc.DCC {
	layerName := "TR"
	switch strings.ToUpper(layer) {
	case "HD": // Head
		layerName = v.object.HD
	case "TR": // Torso
		layerName = v.object.TR
	case "LG": // Legs
		layerName = v.object.LG
	case "RA": // RightArm
		layerName = v.object.RA
	case "LA": // LeftArm
		layerName = v.object.LA
	case "RH": // RightHand
		layerName = v.object.RH
	case "LH": // LeftHand
		layerName = v.object.LH
	case "SH": // Shield
		layerName = v.object.SH
	case "S1": // Special1
		layerName = v.object.S1
	case "S2": // Special2
		layerName = v.object.S2
	case "S3": // Special3
		layerName = v.object.S3
	case "S4": // Special4
		layerName = v.object.S4
	case "S5": // Special5
		layerName = v.object.S5
	case "S6": // Special6
		layerName = v.object.S6
	case "S7": // Special7
		layerName = v.object.S7
	case "S8": // Special8
		layerName = v.object.S8
	}
	if len(layerName) == 0 {
		return d2dcc.DCC{}
	}
	dccPath := fmt.Sprintf("%s/%s/%s/%s%s%s%s%s.dcc", v.base, v.token, layer, v.token, layer, layerName, v.animationMode, v.weaponClass)
	result := d2dcc.LoadDCC(dccPath, fileProvider)
	if !result.IsValid() {
		dccPath = fmt.Sprintf("%s/%s/%s/%s%s%s%s%s.dcc", v.base, v.token, layer, v.token, layer, layerName, v.animationMode, "HTH")
		result = d2dcc.LoadDCC(dccPath, fileProvider)
	}
	return result
}

// If an npc has a path to pause at each location.
// Waits for animation to end and all repetitions to be exhausted.
func (v AnimatedEntity) Wait() bool {
	// currentFrame might skip the final frame if framesToAdd doesn't match up,
	// bail immediately after the last repetition if that happens.
	return v.repetitions < 0 || (v.repetitions == 0 && v.currentFrame >= v.framesToAnimate-1)
}

// Render draws this animated entity onto the target
func (v *AnimatedEntity) Render(target *ebiten.Image, offsetX, offsetY int) {
	if v.animationSpeed > 0 {
		now := d2helper.Now()
		framesToAdd := math.Floor((now - v.lastFrameTime) / v.animationSpeed)
		if framesToAdd > 0 {
			v.lastFrameTime += v.animationSpeed * framesToAdd
			v.currentFrame += int(math.Floor(framesToAdd))
			for v.currentFrame >= v.framesToAnimate {
				v.currentFrame -= v.framesToAnimate
				v.repetitions = d2helper.MinInt32(-1, v.repetitions-1)
			}
		}
	}

	localX := (v.subcellX - v.subcellY) * 16
	localY := ((v.subcellX + v.subcellY) * 8) - 5

	if v.drawOrder == nil {
		return
	}
	for _, layerIdx := range v.drawOrder[v.currentFrame] {
		if v.currentFrame < 0 || v.layerCache[layerIdx].frameSheet == nil || v.currentFrame >= v.framesToAnimate {
			continue
		}
		opts := &ebiten.DrawImageOptions{}
		layer := v.layerCache[layerIdx]
		x := float64(v.offsetX) + float64(offsetX) + localX + float64(v.layerCache[layerIdx].offsetX)
		y := float64(v.offsetY) + float64(offsetY) + localY + float64(v.layerCache[layerIdx].offsetY)
		opts.GeoM.Translate(x, y)
		opts.CompositeMode = v.layerCache[layerIdx].compositeMode
		xOffset := layer.frameWidth * v.currentFrame
		sheetIndex := image.Rect(xOffset, 0, xOffset+layer.frameWidth, layer.frameHeight)
		if err := target.DrawImage(layer.frameSheet.SubImage(sheetIndex).(*ebiten.Image), opts); err != nil {
			log.Panic(err.Error())
		}
	}
}

func (v *AnimatedEntity) updateFrameCache(resetAnimation bool) {
	if resetAnimation {
		v.currentFrame = 0
	}
	// TODO: This animation data madness is incorrect, yet tasty
	animDataTemp := d2data.AnimationData[strings.ToLower(v.token+v.animationMode+v.weaponClass)]
	if animDataTemp == nil {
		return
	}
	animationData := animDataTemp[0]
	v.animationSpeed = 1.0 / ((float64(animationData.AnimationSpeed) * 25.0) / 256.0)
	v.framesToAnimate = animationData.FramesPerDirection
	v.lastFrameTime = d2helper.Now()

	v.drawOrder = make([][]d2enum.CompositeType, v.framesToAnimate)

	var dccDirection int
	switch v.Cof.NumberOfDirections {
	case 4:
		dccDirection = d2dcc.CofToDir4[v.direction]
	case 8:
		dccDirection = d2dcc.CofToDir8[v.direction]
	case 16:
		dccDirection = d2dcc.CofToDir16[v.direction]
	case 32:
		dccDirection = d2dcc.CofToDir32[v.direction]
	default:
		dccDirection = 0
	}

	for frame := 0; frame < v.framesToAnimate; frame++ {
		v.drawOrder[frame] = v.Cof.Priority[v.direction][frame]
	}

	for cofLayerIdx := range v.Cof.CofLayers {
		layerType := v.Cof.CofLayers[cofLayerIdx].Type
		layerName := DccLayerNames[layerType]
		dccLayer := v.dccLayers[layerName]
		if !dccLayer.IsValid() {
			continue
		}

		minX := int32(10000)
		minY := int32(10000)
		maxX := int32(-10000)
		maxY := int32(-10000)
		for frameIdx := range dccLayer.Directions[dccDirection].Frames {
			minX = d2helper.MinInt32(minX, int32(dccLayer.Directions[dccDirection].Frames[frameIdx].Box.Left))
			minY = d2helper.MinInt32(minY, int32(dccLayer.Directions[dccDirection].Frames[frameIdx].Box.Top))
			maxX = d2helper.MaxInt32(maxX, int32(dccLayer.Directions[dccDirection].Frames[frameIdx].Box.Right()))
			maxY = d2helper.MaxInt32(maxY, int32(dccLayer.Directions[dccDirection].Frames[frameIdx].Box.Bottom()))
		}

		v.layerCache[layerType].offsetX = minX
		v.layerCache[layerType].offsetY = minY
		actualWidth := maxX - minX
		actualHeight := maxY - minY

		if (actualWidth <= 0) || (actualHeight < 0) {
			log.Printf("Animated entity created with an invalid size of (%d, %d)", actualWidth, actualHeight)
			return
		}

		transparency := byte(255)
		if v.Cof.CofLayers[cofLayerIdx].Transparent {
			switch v.Cof.CofLayers[cofLayerIdx].DrawEffect {
			//Lets pick whatever we have that's closest.
			case d2enum.DrawEffectPctTransparency25:
				transparency = byte(64)
			case d2enum.DrawEffectPctTransparency50:
				transparency = byte(128)
			case d2enum.DrawEffectPctTransparency75:
				transparency = byte(192)
			case d2enum.DrawEffectModulate:
				v.layerCache[layerType].compositeMode = ebiten.CompositeModeLighter
			case d2enum.DrawEffectBurn:
				// Flies in tal rasha's tomb use this
			case d2enum.DrawEffectNormal:
			}
		}

		pixels := make([]byte, int32(v.framesToAnimate)*(actualWidth*actualHeight*4))

		for animationIdx := 0; animationIdx < v.framesToAnimate; animationIdx++ {
			if animationIdx >= len(dccLayer.Directions[dccDirection].Frames) {
				log.Printf("Invalid animation index of %d for animated entity", animationIdx)
				continue
			}
			sheetOffset := int(actualWidth) * animationIdx
			combinedWidth := int(actualWidth) * v.framesToAnimate

			frame := dccLayer.Directions[dccDirection].Frames[animationIdx]
			for y := 0; y < dccLayer.Directions[dccDirection].Box.Height; y++ {
				for x := 0; x < dccLayer.Directions[dccDirection].Box.Width; x++ {
					paletteIndex := frame.PixelData[x+(y*dccLayer.Directions[dccDirection].Box.Width)]
					if paletteIndex == 0 {
						continue
					}
					color := d2datadict.Palettes[v.palette].Colors[paletteIndex]
					actualX := (x + dccLayer.Directions[dccDirection].Box.Left) - int(minX)
					actualY := (y + dccLayer.Directions[dccDirection].Box.Top) - int(minY)
					idx := (sheetOffset + actualX + ((actualY) * combinedWidth)) * 4
					pixels[idx] = color.R
					pixels[idx+1] = color.G
					pixels[idx+2] = color.B
					pixels[idx+3] = transparency
				}
			}
		}
		v.layerCache[layerType].frameSheet, _ = ebiten.NewImage(int(actualWidth)*v.framesToAnimate, int(actualHeight), ebiten.FilterNearest)
		_ = v.layerCache[layerType].frameSheet.ReplacePixels(pixels)
		v.layerCache[layerType].frameWidth = int(actualWidth)
		v.layerCache[layerType].frameHeight = int(actualHeight)
	}
}

func (v AnimatedEntity) GetDirection() int {
	return v.direction
}

func (v *AnimatedEntity) getStepLength(tickTime float64) (float64, float64) {
	speed := 6.0
	length := tickTime * speed

	angle := 359 - d2helper.GetAngleBetween(
		v.LocationX,
		v.LocationY,
		v.TargetX,
		v.TargetY,
	)
	radians := (math.Pi / 180.0) * float64(angle)
	oneStepX := length * math.Cos(radians)
	oneStepY := length * math.Sin(radians)
	return oneStepX, oneStepY
}

func (v *AnimatedEntity) Step(tickTime float64) {
	stepX, stepY := v.getStepLength(tickTime)

	if d2helper.AlmostEqual(v.LocationX, v.TargetX, stepX) {
		v.LocationX = v.TargetX
	}
	if d2helper.AlmostEqual(v.LocationY, v.TargetY, stepY) {
		v.LocationY = v.TargetY
	}
	if v.LocationX != v.TargetX {
		v.LocationX += stepX
	}
	if v.LocationY != v.TargetY {
		v.LocationY += stepY
	}

	v.subcellX = 1 + math.Mod(v.LocationX, 5)
	v.subcellY = 1 + math.Mod(v.LocationY, 5)
	v.TileX = int(v.LocationX / 5)
	v.TileY = int(v.LocationY / 5)

	if v.LocationX == v.TargetX && v.LocationY == v.TargetY {

		v.repetitions = 3 + rand.Int31n(5)
		newAnimationMode := d2enum.AnimationModeObjectNeutral
		// TODO: Figure out what 1-3 are for, 4 is correct.
		switch v.action {
		case 1:
			newAnimationMode = d2enum.AnimationModeMonsterNeutral
		case 2:
			newAnimationMode = d2enum.AnimationModeMonsterNeutral
		case 3:
			newAnimationMode = d2enum.AnimationModeMonsterNeutral
		case 4:
			newAnimationMode = d2enum.AnimationModeMonsterSkill1
			v.repetitions = 0
		}

		if v.animationMode != newAnimationMode.String() {
			v.SetMode(newAnimationMode.String(), v.weaponClass, v.direction)
		}

	}
}

// SetTarget sets target coordinates and changes animation based on proximity and direction
func (v *AnimatedEntity) SetTarget(tx, ty float64, action int32) {
	angle := 359 - d2helper.GetAngleBetween(
		v.LocationX,
		v.LocationY,
		tx,
		ty,
	)

	v.action = action
	// TODO: Check if is in town and if is player.
	newAnimationMode := d2enum.AnimationModeMonsterWalk.String()
	if tx != v.LocationX || ty != v.LocationY {
		v.TargetX, v.TargetY = tx, ty
		newAnimationMode = d2enum.AnimationModeMonsterWalk.String()
	}

	newDirection := angleToDirection(float64(angle), v.Cof.NumberOfDirections)
	if newDirection != v.GetDirection() || newAnimationMode != v.animationMode {
		v.SetMode(newAnimationMode, v.weaponClass, newDirection)
	}
}

func angleToDirection(angle float64, numberOfDirections int) int {
	if numberOfDirections == 0 {
		return 0
	}

	degreesPerDirection := 360.0 / float64(numberOfDirections)
	offset := 45.0 - (degreesPerDirection / 2)
	newDirection := int((angle - offset) / degreesPerDirection)
	if newDirection >= numberOfDirections {
		newDirection = newDirection - numberOfDirections
	} else if newDirection < 0 {
		newDirection = numberOfDirections + newDirection
	}

	return newDirection
}

func (v *AnimatedEntity) Advance(tickTime float64) {

}

func (v *AnimatedEntity) GetPosition() (float64, float64) {
	return float64(v.TileX), float64(v.TileY)
}