/// <reference path="../../../dist/preview release/babylon.d.ts"/>

module BABYLON {
    export class OBJExport {
        //Exports the geometry of a Mesh array in .OBJ file format (text)
        public static OBJ(mesh: Mesh[], materials?: boolean, matlibname?: string, globalposition?: boolean): string {
            const output:string[] = [];
            let v = 1;
            if (materials) {
                if (!matlibname) {
                    matlibname = 'mat';
                }
                output.push("mtllib " + matlibname + ".mtl");
            }
            for (let j = 0; j < mesh.length; j++) {
                output.push("g object" + j);
                output.push("o object_" + j);

                //Uses the position of the item in the scene, to the file (this back to normal in the end)
                let lastMatrix: Nullable<Matrix> = null;
                if (globalposition) {
                    var newMatrix = BABYLON.Matrix.Translation(mesh[j].position.x, mesh[j].position.y, mesh[j].position.z);
                    lastMatrix = BABYLON.Matrix.Translation(-(mesh[j].position.x), -(mesh[j].position.y), -(mesh[j].position.z));
                    mesh[j].bakeTransformIntoVertices(newMatrix);
                }

                //TODO: submeshes (groups)
                //TODO: smoothing groups (s 1, s off);
                if (materials) {
                    let mat = mesh[j].material;

                    if (mat) {
                        output.push("usemtl " + mat.id);
                    }
                }
                const g: Nullable<Geometry> = mesh[j].geometry;

                if (!g) {
                    continue;
                }

                const trunkVerts = g.getVerticesData('position');
                const trunkNormals = g.getVerticesData('normal');
                const trunkUV = g.getVerticesData('uv');
                const trunkFaces = g.getIndices();
                var curV = 0;

                if (!trunkVerts || !trunkFaces) {
                    continue;
                }

                for (var i = 0; i < trunkVerts.length; i += 3) {
                    output.push("v " + trunkVerts[i] + " " + trunkVerts[i + 1] + " " + trunkVerts[i + 2]);
                    curV++;
                }

                if (trunkNormals != null) {
                    for (i = 0; i < trunkNormals.length; i += 3) {
                        output.push("vn " + trunkNormals[i] + " " + trunkNormals[i + 1] + " " + trunkNormals[i + 2]);
                    }
                }
                if (trunkUV != null) {

                    for (i = 0; i < trunkUV.length; i += 2) {
                        output.push("vt " + trunkUV[i] + " " + trunkUV[i + 1]);
                    }
                }

                for (i = 0; i < trunkFaces.length; i += 3) {
                    const indices = [String(trunkFaces[i + 2] + v), String(trunkFaces[i + 1] + v), String(trunkFaces[i] + v)];
                    const blanks: string[] = ["","",""];

                    const facePositions = indices;
                    const faceUVs = trunkUV != null ? indices : blanks;
                    const faceNormals = trunkNormals != null ? indices : blanks;
                         
                    output.push(
                        "f " + facePositions[0] + "/" + faceUVs[0] + "/" + faceNormals[0] +
                        " " + facePositions[1] + "/" + faceUVs[1] + "/" + faceNormals[1] +
                        " " + facePositions[2] + "/" + faceUVs[2] + "/" + faceNormals[2]
                    );
                }
                //back de previous matrix, to not change the original mesh in the scene
                if (globalposition && lastMatrix) {
                    mesh[j].bakeTransformIntoVertices(lastMatrix);
                }
                v += curV;
            }
            const text: string = output.join("\n");
            return (text);
        }
        //Exports the material(s) of a mesh in .MTL file format (text)
        //TODO: Export the materials of mesh array
        public static MTL(mesh: Mesh): string {
            var output = [];
            var m = <StandardMaterial>mesh.material;
            output.push("newmtl mat1");
            output.push("  Ns " + m.specularPower.toFixed(4));
            output.push("  Ni 1.5000");
            output.push("  d " + m.alpha.toFixed(4));
            output.push("  Tr 0.0000");
            output.push("  Tf 1.0000 1.0000 1.0000");
            output.push("  illum 2");
            output.push("  Ka " + m.ambientColor.r.toFixed(4) + " " + m.ambientColor.g.toFixed(4) + " " + m.ambientColor.b.toFixed(4));
            output.push("  Kd " + m.diffuseColor.r.toFixed(4) + " " + m.diffuseColor.g.toFixed(4) + " " + m.diffuseColor.b.toFixed(4));
            output.push("  Ks " + m.specularColor.r.toFixed(4) + " " + m.specularColor.g.toFixed(4) + " " + m.specularColor.b.toFixed(4));
            output.push("  Ke " + m.emissiveColor.r.toFixed(4) + " " + m.emissiveColor.g.toFixed(4) + " " + m.emissiveColor.b.toFixed(4));

            //TODO: uv scale, offset, wrap
            //TODO: UV mirrored in Blender? second UV channel? lightMap? reflection textures?
            var uvscale = "";

            if (m.ambientTexture) {
                output.push("  map_Ka " + uvscale + m.ambientTexture.name);
            }

            if (m.diffuseTexture) {
                output.push("  map_Kd " + uvscale + m.diffuseTexture.name);
                //TODO: alpha testing, opacity in diffuse texture alpha channel (diffuseTexture.hasAlpha -> map_d)
            }

            if (m.specularTexture) {
                output.push("  map_Ks " + uvscale + m.specularTexture.name);
                /* TODO: glossiness = specular highlight component is in alpha channel of specularTexture. (???)
                if (m.useGlossinessFromSpecularMapAlpha)  {
                    output.push("  map_Ns "+uvscale + m.specularTexture.name);
                }
                */
            }

            /* TODO: emissive texture not in .MAT format (???)
            if (m.emissiveTexture) {
                output.push("  map_d "+uvscale+m.emissiveTexture.name);
            }
            */

            if (m.bumpTexture) {
                output.push("  map_bump -imfchan z " + uvscale + m.bumpTexture.name);
            }

            if (m.opacityTexture) {
                output.push("  map_d " + uvscale + m.opacityTexture.name);
            }

            var text = output.join("\n");
            return (text);
        }
    }
}