use std::ops::{Index,IndexMut};
use std::borrow::{Borrow,BorrowMut};
use std::slice;
use std::vec;
use std::iter::{FromIterator, IntoIterator};
use std::io::BufRead;
use super::vertex::*;
#[cfg(any(feature="gl", feature="gles", feature="webgl"))]
use glin;
#[cfg(any(feature="gl", feature="gles", feature="webgl"))]
use super::primitive_type_to_gl;

use na::*;
use color::ToRgba;
use std::path::Path;
use std::io;
use std::fs::File;
use std::mem;

#[cfg(not(target_os="android"))]
pub type IndexT = u32;
#[cfg(target_os="android")]
pub type IndexT = u16;

/// A Mesh with any vertex type
///
/// Contains vertices that can be of any type although
/// rin define a few of the most commonly used and optionally
/// indices
///
/// Also a primitive type that defines how the vertices / indices
/// should be parsed
#[derive(Debug,Clone)]
#[cfg_attr(feature = "serialize", derive(Serialize, Deserialize))]
pub struct Mesh<T>{
    vertices: Vec<T>,
    indices: Vec<IndexT>,
    primitive_type: PrimitiveType,
}

impl<T> Default for Mesh<T>{
    fn default() -> Mesh<T>{
        Mesh{
            vertices: vec![],
            indices: vec![],
            primitive_type: PrimitiveType::Triangles,
        }
    }
}

/// Mesh with no indices from vertices and primitive type
pub fn mesh<T: Clone>(vertices: Vec<T>, ty: PrimitiveType) ->Mesh<T>{
    Mesh::from_vertices_and_type(vertices,ty)
}

impl<T: Clone> Mesh<T>{
    /// Mesh from vertices, indices and primitive type
    pub fn new(vertices: Vec<T>, indices: Vec<IndexT>, primitive_type: PrimitiveType) -> Mesh<T>{
        Mesh{vertices, indices, primitive_type}
    }

    /// Triangles mesh from vertices with no indices
    pub fn from_vertices(vertices: Vec<T>) -> Mesh<T>{
        Mesh{vertices: vertices, indices: Vec::new(), primitive_type: PrimitiveType::Triangles}
    }

    /// Mesh with no indices from vertices and primitive type
    pub fn from_vertices_and_type(vertices: Vec<T>, ty: PrimitiveType) -> Mesh<T>{
        Mesh{vertices: vertices, indices: Vec::new(), primitive_type: ty}
    }

    /// Mesh with no indices from vertices iterator and primitive type
    pub fn from_iter_and_type<I: Iterator<Item=T>>(vertices: I, ty: PrimitiveType) -> Mesh<T>{
        Mesh{vertices: vertices.collect(), indices: Vec::new(), primitive_type: ty}
    }

    /// Triangles mesh from vertices and indices
    pub fn from_vertices_indices(vertices: Vec<T>, indices: Vec<IndexT>) -> Mesh<T>{
        Mesh{vertices: vertices, indices: indices, primitive_type: PrimitiveType::Triangles}
    }

    /// Empty mesh with the specified primitive type
    pub fn with_type(ty: PrimitiveType) -> Mesh<T>{
         Mesh{vertices: Vec::new(), indices: Vec::new(), primitive_type: ty}
    }

    /// Set the mesh vertices
    pub fn set_vertices(&mut self, vertices: Vec<T>){
        self.vertices = vertices;
    }

    /// Set the mesh vertices
    pub fn set_indices(&mut self, indices: Vec<IndexT>){
        self.indices = indices;
    }

    pub fn indices(&self) -> &Vec<IndexT>{
        &self.indices
    }

    pub fn indices_mut(&mut self) -> &mut Vec<IndexT>{
        &mut self.indices
    }

    pub fn vertices(&self) -> &[T]{
        &self.vertices
    }

    pub fn vertices_mut(&mut self) -> &mut [T]{
        &mut self.vertices
    }

    /// Iterator over the mesh vertices in the order they where inserted
    pub fn iter(&self) -> slice::Iter<T>{
        self.vertices.iter()
    }

    /// Mutable iterator over the mesh vertices in the order they where inserted
    pub fn iter_mut(&mut self) -> slice::IterMut< T>{
        self.vertices.iter_mut()
    }

    /// Consume the mesh into an iterator over it's vertices in the order they where inserted
    pub fn into_iter(self) -> vec::IntoIter<T>{
        self.vertices.into_iter()
    }

    /// Pop the last vertex
    pub fn pop(&mut self) -> Option<T>{
        self.vertices.pop()
    }

    /// Push a vertex at the end of the mesh
    pub fn push(&mut self, value: T){
        self.vertices.push(value);
    }

    /// Extend the mesh with a slice of new vertices
    pub fn extend_from_slice(&mut self, other: &[T]){
        self.vertices.extend_from_slice(other);
    }

    /// Extend the mesh with another mesh
    ///
    /// The vertices and indices will just be inserted at the end
    /// without taking into account the primitive types
    pub fn extend_from_mesh(&mut self, other: &Mesh<T>){
        let offset = self.vertices.len() as u32;
        self.vertices.extend_from_slice(other.vertices());
        self.indices.extend(other.indices().iter().map(|i| i + offset));
    }

    /// Extend the mesh with an iterator of new vertices
    pub fn extend<I: IntoIterator<Item=T>>(&mut self, other: I){
        self.vertices.extend(other);
    }

    /// Insert a vertex at a certain position
    pub fn insert(&mut self, index: usize, element: T){
        self.vertices.insert(index, element);
    }

    /// Mutably get the vertex at the specified position.
    ///
    /// Will panic if the vertex doesn't exist
    pub fn get_mut(&mut self, index: usize) -> &mut T{
        self.vertices.get_mut(index).unwrap()
    }

    /// Reserve as much capacity for vertices
    pub fn reserve(&mut self, capacity: usize){
        self.vertices.reserve(capacity);
    }

    /// Unsafe operation that sets the len of the vertices
    /// collection
    pub unsafe fn set_len(&mut self, len: usize){
        self.vertices.set_len(len);
    }

    /// Truncate the mesh vertices at the specified len
    pub fn truncate(&mut self, len: usize){
        self.vertices.truncate(len);
    }

    /// Last vertex if there's any
    pub fn last(&self) -> Option<&T>{
        self.vertices.last()
    }

    /// Last vertex mutably if there's any
    pub fn last_mut(&mut self) -> Option<&mut T>{
        self.vertices.last_mut()
    }

    /// Primitive type
    pub fn primitive_type(&self) -> PrimitiveType{
        self.primitive_type
    }

    pub fn set_primitive_type(&mut self, ty: PrimitiveType){
        self.primitive_type = ty;
    }

    /// Add a triangle face (only for Triangles primitive type)
    pub fn add_face(&mut self, i0: IndexT, i1: IndexT, i2: IndexT){
        self.indices.push(i0);
        self.indices.push(i1);
        self.indices.push(i2);
    }

    /// Clear the mesh vertices and indices
    pub fn clear(&mut self){
        self.vertices.clear();
        self.indices.clear();
    }

    /// Clear the vertices
    pub fn clear_vertices(&mut self){
        self.vertices.clear();
    }

    /// Clear the indices
    pub fn clear_indices(&mut self){
        self.indices.clear();
    }

    /// Number of vertices
    pub fn len(&self) -> usize{
        self.vertices.len()
    }

    /// Contains any vertices
    pub fn is_empty(&self) -> bool{
        self.vertices.is_empty()
    }

    pub fn faces(&self) -> Box<Iterator<Item = [&T; 3]> + '_>{
        if self.indices.is_empty(){
            Box::new(self.vertices.chunks(3).map(|tri| [
                &tri[0],
                &tri[1],
                &tri[2],
            ]))
        }else if self.primitive_type() == PrimitiveType::Triangles{
            Box::new(self.indices.chunks(3).map(move |tri| [
                &self.vertices[tri[0] as usize],
                &self.vertices[tri[1] as usize],
                &self.vertices[tri[2] as usize],
            ]))
        }else{
            unimplemented!()
        }
    }

    pub fn faces_mut(&mut self) -> Box<Iterator<Item = [&mut T; 3]> + '_>{
        if self.primitive_type() == PrimitiveType::Triangles{
            if self.indices.is_empty(){
                Box::new(self.vertices.chunks_mut(3).map(|tri| [
                    unsafe{ mem::transmute(&mut tri[0]) },
                    unsafe{ mem::transmute(&mut tri[1]) },
                    unsafe{ mem::transmute(&mut tri[2]) },
                ]))
            }else{
                let indices = &self.indices;
                let vertices: &mut Vec<T> = unsafe{ mem::transmute(&mut self.vertices) };
                Box::new(indices.chunks(3).map(move |tri| [
                    unsafe{ mem::transmute(&mut vertices[tri[0] as usize]) },
                    unsafe{ mem::transmute(&mut vertices[tri[1] as usize]) },
                    unsafe{ mem::transmute(&mut vertices[tri[2] as usize]) },
                ]))
            }
        }else{
            unimplemented!()
        }
    }
}

impl<T> Index<usize> for Mesh<T>{
	type Output = T;
    fn index(&self, index: usize) -> &T{
        self.vertices.index(index)
    }
}

impl<T> IndexMut<usize> for Mesh<T>{
    fn index_mut(&mut self, index: usize) -> &mut T{
        self.vertices.index_mut(index)
    }
}

impl<T> AsRef<[T]> for Mesh<T>{
    fn as_ref(&self) -> &[T]{
        self.vertices.as_ref()
    }
}

impl<T> AsMut<[T]> for Mesh<T>{
    fn as_mut(&mut self) -> &mut [T]{
        self.vertices.as_mut()
    }
}

impl<T> Into<Vec<T>> for Mesh<T>{
    fn into(self) -> Vec<T>{
        self.vertices
    }
}

impl<T> Into<(Vec<T>, Vec<IndexT>)> for Mesh<T>{
    fn into(self) -> (Vec<T>, Vec<IndexT>){
        (self.vertices, self.indices)
    }
}

impl<T> Borrow<[T]> for Mesh<T>{
    fn borrow(&self) -> &[T]{
        self.vertices.borrow()
    }
}

impl<T> BorrowMut<[T]> for Mesh<T>{
    fn borrow_mut(&mut self) -> &mut [T]{
        self.vertices.borrow_mut()
    }
}

impl<T> FromIterator<T> for Mesh<T>{
    fn from_iter<I>(iter: I) -> Mesh<T> where I: IntoIterator<Item=T>{
        Mesh{
            vertices: iter.into_iter().collect(),
            indices: vec![],
            primitive_type: PrimitiveType::Triangles
        }
    }
}

#[derive(Clone,Copy,Debug,Eq,PartialEq)]
#[cfg_attr(feature = "serialize", derive(Serialize, Deserialize))]
pub enum PrimitiveType{
    Triangles,
    TriangleStrip,
    TriangleFan,
    Lines,
    LineStrip,
    LineLoop,
    LinesAdjacency,
    LineStripAdjacency,
    Points,
    Patches
}

impl Default for PrimitiveType{
    fn default() -> PrimitiveType {
        PrimitiveType::Triangles
    }
}

/// Load a ply into a Mesh
pub fn load_ply<C: ToRgba, P: AsRef<Path>>(path: P, default_color: C) -> Result<Mesh<Vertex3DTexColor>,String>{
    // let reader = io::file_reader(path).map_err(|err| format!("Couldn't open {}: {:?}", path, err))?;
    let file = File::open(path.as_ref())
        .map_err(|err| format!("Couldn't open {}: {:?}", path.as_ref().display(), err))?;
    let reader = io::BufReader::new(file);
    let mut mesh: Mesh<Vertex3DTexColor> = Mesh::default();
    let mut first_line = true;
    let mut vertex_dim = 0;
    let mut texcoord_dim = 0;
    let mut color_dim = 0;
    let mut state = "init".to_string();
    let mut idx = 0;
    for line in reader.lines() {
        let line = line.unwrap().trim_right_matches([' ','\n'].as_ref()).to_string();
        if first_line && line!="ply"{
            return Err("couldn't read file, ply not found on first line".to_string());
        }
        first_line = false;

        if line.starts_with("format"){
            if line != "format ascii 1.0"{
                return Err(format!("{}, not supported",line));
            }
            continue;
        }

        if line.starts_with("element"){
            let element_ty_len: Vec<&str> = line.split(' ').collect();
            let ty = element_ty_len[1];
            let len = element_ty_len[2];
            if ty == "vertex"{
				unsafe{
					let new_len = len.parse().unwrap();
					mesh.reserve(new_len);
					mesh.set_len(new_len);
				}
            }
            state = ty.to_string();
            println!("state: {}",state);
            continue;
        }

        if line.starts_with("property"){
            //let property_ty_name: ~[&str] = line.split(' ').collect();
            println!("state on property: {}",state);
            match state.as_ref(){
                "vertex" => vertex_dim+=1,
                "texcoord" => texcoord_dim+=1,
                "color" => color_dim+=1,
                _ => {}
            }
            continue;
        }

        if line == "end_header"{
            state = "vertices".to_string();
            continue;
        }

        if state == "vertices"{
            //println!("{} vertex dim",vertex_dim);
            let components: Vec<&str> = line.split(' ').collect();
            let mut next_pos = 0;
            if idx<mesh.vertices.len(){
                if vertex_dim == 2{
                    let pos = vec3(components[next_pos].parse().unwrap(),components[next_pos+1].parse().unwrap(),0.0);
                    mesh[idx].position = pos;
                    next_pos = 3;
                }else if vertex_dim >= 3{
                    let pos = vec3(components[next_pos].parse().unwrap(),components[next_pos+1].parse().unwrap(),components[next_pos+2].parse().unwrap());
                    mesh[idx].position = pos;
                    next_pos = vertex_dim+1;
                }

                if texcoord_dim >= 2{
                    let texcoord = vec2(components[next_pos].parse().unwrap(),components[next_pos+1].parse().unwrap());
                    mesh[idx].texcoord = texcoord;
                    next_pos += texcoord_dim;
                }else{
                    mesh[idx].texcoord = zero();
                }

                if color_dim >= 3{
                    let r = components[next_pos].parse().unwrap();
                    let g = components[next_pos+1].parse().unwrap();
                    let b = components[next_pos+2].parse().unwrap();
                    if color_dim == 3{
                        let color = rgba!(r,g,b,1.0f32);
                        mesh[idx].color = color;
                        //next_pos += color_dim;
                    }else if color_dim >= 4{
                        let a = components[next_pos+3].parse().unwrap();
                        let color = rgba!(r,g,b,a);
                        mesh[idx].color = color;
                        //next_pos += color_dim;
                    }
                }else{
                    mesh[idx].color = default_color.to_rgba();
                }
                idx += 1;
            }else{
                state = "faces".to_string();
                idx = 0;
            }
        }

        if state == "faces"{
            let components: Vec<&str> = line.split(' ').collect();
            let num_components: usize = components[0].parse().unwrap();
            if num_components == 3 {
                mesh.add_face(components[1].parse().unwrap(), components[2].parse().unwrap(), components[3].parse().unwrap());
            }else if num_components == 4{
                mesh.add_face(components[1].parse().unwrap(), components[2].parse().unwrap(), components[3].parse().unwrap());
                mesh.add_face(components[3].parse().unwrap(), components[4].parse().unwrap(), components[1].parse().unwrap());
            }
            idx += 1;
        }
    }

    Ok(mesh)
}


#[cfg(any(feature="gl", feature="gles", feature="webgl"))]
impl<'a,T: Clone> Into<glin::simple_vao::Data<'a,T>> for &'a Mesh<T>{
    fn into(self) -> glin::simple_vao::Data<'a,T>{
        glin::simple_vao::Data{
            vertices: self,
            indices: self.indices(),
            mode: primitive_type_to_gl(self.primitive_type())
        }
    }
}