package tile

import "gitlab.com/beoran/ebsgo/monolog"
import "fmt"
import "strings"
import "bytes"
import "strconv"
import "io/ioutil"
import "compress/gzip"
import "compress/zlib"
import "encoding/binary"
import "encoding/base64"


import "gitlab.com/beoran/al5go/al"
// import "gitlab.com/beoran/ebsgo/engine/geometry/point"
// import "gitlab.com/beoran/ebsgo/engine/physics/camera"
import "gitlab.com/beoran/ebsgo/engine/fifi"

import "github.com/beevik/etree"


// Tile flipping constants
const (
    TMX_FLIPPED_HORIZONTALLY = 0x80000000
    TMX_FLIPPED_VERTICALLY   = 0x40000000
    TMX_FLIPPED_DIAGONALLY   = 0x20000000
    TMX_FLIPPED_FILTER       = (^uint32(0xE0000000))
)


func AttrInt(e * etree.Element, key string) (int, error) {
    return strconv.Atoi(e.SelectAttrValue(key, ""))
}

func AttrFloat64(e * etree.Element, key string) (float64, error) {
    return strconv.ParseFloat(e.SelectAttrValue(key, ""), 64)
}


func Property(e * etree.Element, propname string) (string, bool) {
  properties := e.FindElements("//properties/property")
  
  for _, property := range properties {
        name := property.SelectAttrValue("name", "")
        if name == propname {
            return property.SelectAttrValue("value", ""), true
        }
  }
  
  return "", false
}

func PropertyInt(e * etree.Element, propname string) (int, error) {
    value , ok := Property(e, propname)
    if (!ok) {
        return 0, fmt.Errorf("no such property")
    }
    
    return strconv.Atoi(value)
} 


func LoadFrame(xml_frame * etree.Element, tile * Tile, set * Set) * Tile {
    tile_id, err := AttrInt(xml_frame, "tileid")
    if err != nil {
        return tile;
    }
    
    // the tile id obtained here is correct and doesn't need to be 
    // lessened by firstgid
    
    duration, err := AttrFloat64(xml_frame, "duration")
    
    if err != nil {
        return tile;
    }
    
    /* Convert ms to s. */ 
    duration /= 1000.0
    
    frame := tile.AddAnimationFrame(tile_id, duration)
    
    monolog.Log("TILEIO", "Frame loaded: %d %f", frame.Index, frame.Duration)
    
    return tile
}


func LoadAnimation(xml_tile * etree.Element, tile * Tile, set * Set) * Tile {
    xml_anim := xml_tile.FindElement("//animation")
    if xml_anim == nil {
        return tile;
    }
    
    xml_frames := xml_anim.FindElements("//frame")
    for _, xml_frame := range xml_frames {
        LoadFrame(xml_frame, tile, set)
    }

    
    monolog.Log("TILEIO", "Loaded animation: %d", len(tile.Frames))
    return tile
}

func XmlToTileType(xml_tile * etree.Element) (uint, error) {
    
    value , ok := Property(xml_tile, "type")
    if (!ok) {
        return 0, fmt.Errorf("no type property")
    }
    
    result, ok  := FlagNames[value]
    
    if ! ok {
        return 0, fmt.Errorf("unknown type property")
    }
    
    return result, nil
} 


func LoadTile(xml_tile * etree.Element, index int, set * Set, tm * Map) (*Tile, error) {
     
    id, err := AttrInt(xml_tile, "id") 
 
    if err != nil { 
        return nil, fmt.Errorf("Tile id not found: %s", err)
    }
  
    tile := set.Tile(id)
    monolog.Log("TILEIO", "Got tile: %d <- %d", tile.Active, tile.Index)
    
    
    if tile == nil { 
        return nil, fmt.Errorf("Tile id not found in tile set: %d", id)
    }
    
    value , ok := Property(xml_tile, "type")
    if (ok) {
        parts := strings.Split(value, ",") 
        for _, part := range parts {
            clean := strings.Trim(part, "")
            tile.SetProperty(clean)
        }
    }
    
    // ianim       , err := PropertyInt(xml_tile, "anim"       )
    // iwait       , err := PropertyInt(xml_tile, "wait"       )
    ilight      , err := PropertyInt(xml_tile, "light"      )
    iblend      , err := PropertyInt(xml_tile, "blend"      )
    ishadow     , err := PropertyInt(xml_tile, "shadow"     )
    ilightmask  , err := PropertyInt(xml_tile, "lightmask"  )
    iblendmask  , err := PropertyInt(xml_tile, "blendmask"  )
    ishadowmask , err := PropertyInt(xml_tile, "shadowmask" )
    
    // No support anymore for "classic" animations since TMX now 
    // supports animations.
    tile.Light      = ilight
    tile.Blend      = iblend
    tile.Shadow     = ishadow
    tile.LightMask  = ilightmask
    tile.BlendMask  = iblendmask
    tile.ShadowMask = ishadowmask

    /* Support tiled-style animations. */
    LoadAnimation(xml_tile, tile, set)
    monolog.Log("TILEIO", "Loaded tile: (%d x %d)", tile.SheetX(tile.Tileset), tile.SheetY(tile.Tileset))
    return tile, nil
}


/** Calculates index and the Allegro draw flags and rotation for a tile. */

func TmxTileIndexFlagsAndRotation(tmx_index uint32) (int, int, float32) { 
    index := int(tmx_index & TMX_FLIPPED_FILTER) 
    flags := int(0)
    rotate := float32(0.0)

    if (tmx_index & TMX_FLIPPED_HORIZONTALLY) != 0 {
        flags |= al.FLIP_HORIZONTAL
    }
   
    if (tmx_index & TMX_FLIPPED_VERTICALLY) != 0 {
        flags |= al.FLIP_VERTICAL
    } 
  
    if (tmx_index & TMX_FLIPPED_DIAGONALLY) != 0 {
        rotate = float32(al.PI / 2.0)
    }

  return index, flags, rotate
}


func LoadSet(xml_set * etree.Element, index int, tm * Map) (* Set, error) { 
    firstgid, err := AttrInt(xml_set, "firstgid")
    if err != nil {
        return nil, fmt.Errorf("Could not find firstgid for tile set %d: %s", index, err)
    }
    
    xml_image := xml_set.FindElement("//image")
    
    if xml_image == nil {
        return nil, fmt.Errorf("Could not find image data for tile set %d", index)
    }
    
    tile_w, err := AttrInt(xml_set, "tilewidth")
    tile_h, err := AttrInt(xml_set, "tilewidth")
    
    if (tile_w < 1) || (tile_h < 1) {
        return nil, fmt.Errorf("Tile size too small for tile set %d: %d x %d", index, tile_w, tile_h)
    }
    
    iname   := xml_image.SelectAttrValue("source", "tile_set_default.png")    
    bmp     := fifi.LoadBitmap("map/" + iname)
    
    if bmp == nil {
        return nil, fmt.Errorf("Could not load tile set sheet: %s", iname)
    }
    
    set     := NewSet(bmp, tile_w, tile_h, firstgid)
    monolog.Log("TILEIO", "Loaded tile set: (%d x %d) (%d x %d) %d", set.TileW, set.TileH, set.W, set.H, set.FirstGID)
    
    xml_tiles := xml_set.FindElements("//tile")
    
    for tile_index, xml_tile := range xml_tiles {
        LoadTile(xml_tile, tile_index, set, tm)
    }
    
    set.Recalculate()
    
    return set, nil
}

type Expander func(in []byte) ([]byte, error) 

type Decoder func(data string, w, h int, expand Expander) ([][]uint32, error) 


func CsvDecoder(data string, w, h int, expand Expander) ([][]uint32, error) {
    lines := strings.Split(data, "\n")
    x := 0
    y := 0
    
    result := make([][]uint32, h)     
    for _, line := range lines {
        if line != "" {
            cells := strings.Split(line, ",")
            result[y] = make([]uint32, w)
            for x = 0 ; x < w ; x++ {
                value := uint32(0)
                if ( x >= len(cells)  ) {
                    break;
                }
                res, err := strconv.ParseUint(cells[x], 10, 32) 
                if err == nil {
                    value = uint32(res)
                }
                result[y][x] = value
            }
            y++    
        }
        if y >= h {
            break;
        }
    }
    return result, nil
}

func GzipExpander(in []byte) ([]byte, error) {
    zr, err := gzip.NewReader(bytes.NewReader(in))
    if err != nil {
        return nil, err
    }
    return ioutil.ReadAll(zr)
}

func ZlibExpander(in []byte) ([]byte, error) {
    zr, err := zlib.NewReader(bytes.NewReader(in))
    if err != nil {
        return nil, err
    }
    return ioutil.ReadAll(zr)
}


func Base64Decoder(data string, w, h int, expand Expander) ([][]uint32, error) {
    bytes, err := base64.StdEncoding.DecodeString(data)
    if err != nil {
        return nil, err
    }
    
    if expand != nil {
        bytes, err = expand(bytes)
        if err != nil {
            return nil, err
        }
    }
    
    result := make([][]uint32, h) 
    for i := 0 ; i < h; i++ { 
        result[i] = make([]uint32, w) 
        for j := 0 ; i < w ; j++ { 
            index := (i * w + j) * 4
            value := binary.LittleEndian.Uint32(bytes[index:4])
            result[i][j] = value
        }
    }

    return result, nil
}

var Decoders map[string]Decoder = map[string]Decoder {
    "csv"   : CsvDecoder,
    "base64": Base64Decoder,
}

var Expanders map[string]Expander = map[string]Expander {
    "gzip"   : GzipExpander,
    "zlib": ZlibExpander,
}



// Loads a single tile pane of the tile map from xml (tmx). 
func LoadPane(xml_pane * etree.Element, index int, tm * Map) (* Pane, error) {  
    width, err := AttrInt(xml_pane, "width")
    height, err := AttrInt(xml_pane, "height")
  
    if (width < 1) || (height < 1) {
        return nil, 
        fmt.Errorf("Layer %i size too small: %d x %d, ", index, width, height)
    }
    
    name := xml_pane.SelectAttrValue("name", "")
    
    iset, err := PropertyInt(xml_pane, "tileset")
    
    if err != nil {
        iset = 0
    }
    
    set := tm.Set(iset)
    
    if set == nil {
      return nil, 
      fmt.Errorf("No tile set found for layer %d: %d", index, iset)
    }
    
    pane := NewPane(set, width, height, name)
    
    xml_data := xml_pane.FindElement("//data")
    
    if xml_data == nil {
        return nil, fmt.Errorf("Cannot find layer data for layer %d", index)
    }
    
    encoding    := xml_data.SelectAttrValue("encoding"   , "csv")
    compression := xml_data.SelectAttrValue("compression", "")
    
    decoder     := Decoders[encoding]
    
    if decoder == nil {
        return nil, fmt.Errorf("Unknown encoding %s", encoding)
    }
    
    expander    := Expanders[compression]
    
    grid, err   := decoder(xml_data.Text(), width, height, expander) 

    if err != nil {
        return nil, fmt.Errorf("Could not decode data for layer %d: %s %s: %s;\nData:>%s<",
         index, encoding, compression, err, xml_data.Text())
    }
    
    monolog.Log("TILEIO", "Loaded grid size: (%d x %d) vs size (%d x %d)\n",len(grid), len(grid[0]), height, width)
    
    for y := 0 ; y < height ; y ++ {
        row := grid[y]
        for x := 0 ; x < width && x < len(row)  ; x++ {
            tmx_index := row[x]
            if tmx_index == 0 { 
                pane.SetTile(x, y, nil)
            } else {
                index, flags, rotation := TmxTileIndexFlagsAndRotation(tmx_index)
                if pane.Tileset == nil {
                    pane.Tileset = tm.LookupTmxTileset(index)
                }
                ebs_index   := index - pane.FirstGID() // + 1 
                cell        := pane.Cell(x, y)
                cell.Tile    = pane.Tileset.Tile(ebs_index)
                cell.Flags   = flags
                cell.Rotate  = rotation
            }
        }
    }
    return pane, nil
}


// Load a TMX map file from the given XML document.
func LoadMapXml(doc * etree.Document) (* Map, error) {
    root := doc.Root()
    if root.Tag != "map" {
        return nil, fmt.Errorf("File is not a TMX map file: %s", root.Tag)
    }
    
    wide, err := AttrInt(root, "width")
    
    if err != nil {
        return nil, fmt.Errorf("Width not a number: %s", err)
    }
    
    high, err := AttrInt(root, "height"); 
    if err != nil {
        return nil, fmt.Errorf("Height not a number: %s", err)
    }
    
    if (wide < 1)  || (high < 1) {
        return nil, fmt.Errorf("Map size too smalll: %d x %d",wide, high)
    }
    
    tm := NewMap(wide, high)
    
    xml_sets := root.FindElements("//tileset")
    
    for i, xml_set := range xml_sets {
        set, err := LoadSet(xml_set, i, tm)
        if err != nil {
            return nil, fmt.Errorf("Could not load tile set: %s", err)
        } else {
            _ = tm.AddSet(set)
        }
    }
    
    xml_panes := root.FindElements("//layer")
    
    for i, xml_pane := range xml_panes {
        pane, err := LoadPane(xml_pane, i, tm)
        if err != nil {
            return nil, fmt.Errorf("Could not load tile layer: %s", err)
        } else {
            tm.AddPane(pane)
        }
    }
      
  return tm, nil;          
}

// Loads a TMX tile map from the named file.
// Return nil on error.
func LoadMap(filename string) (* Map, error) {
    doc := etree.NewDocument()
    err := doc.ReadFromFile(filename)
    if err != nil {
        return nil, err
    }
    return LoadMapXml(doc)
}


func LoadMapFifi(relname string) (* Map, error) {
    realname := fifi.Map(relname)
    return LoadMap(realname)
}