use super::instructions::*;
use alloc::string::String;
use alloc::vec::Vec;
use core::convert::TryFrom;
use core::convert::TryInto;
use serde::{Deserialize, Serialize};
use webassembly::*;

pub trait WasmValueTypes {
    fn try_to_value_types(self) -> Result<Vec<ValueType>, &'static str>;
}

#[derive(Clone, PartialEq, Copy, Debug, Serialize, Deserialize)]
#[repr(C)]
pub enum ValueType {
    I32,
    I64,
    F32,
    F64,
}

impl ValueType {
    pub fn into_wasm_byte(self) -> u8 {
        match self {
            ValueType::I32 => I32,
            ValueType::I64 => I64,
            ValueType::F32 => F32,
            ValueType::F64 => F64,
        }
    }
}

impl TryFrom<u8> for ValueType {
    type Error = &'static str;

    fn try_from(value: u8) -> Result<Self, Self::Error> {
        match value {
            I32 => Ok(ValueType::I32),
            I64 => Ok(ValueType::I64),
            F32 => Ok(ValueType::F32),
            F64 => Ok(ValueType::F64),
            _ => Err("could not convert data type"),
        }
    }
}

impl WasmValueTypes for Vec<u8> {
    fn try_to_value_types(self) -> Result<Vec<ValueType>, &'static str> {
        let mut r = vec![];
        for v in self {
            r.push(v.try_into()?);
        }
        Ok(r)
    }
}

impl TryFrom<&u8> for ValueType {
    type Error = &'static str;

    fn try_from(value: &u8) -> Result<Self, Self::Error> {
        match *value {
            I32 => Ok(ValueType::I32),
            I64 => Ok(ValueType::I64),
            F32 => Ok(ValueType::F32),
            F64 => Ok(ValueType::F64),
            _ => Err("could not convert data type"),
        }
    }
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct FunctionType {
    pub inputs: Vec<ValueType>,
    pub outputs: Vec<ValueType>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct TypeSection {
    pub types: Vec<FunctionType>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct FunctionSection {
    pub function_types: Vec<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct LocalCount {
    pub count: u32,
    pub value_type: ValueType,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct CodeBlock {
    pub locals: Vec<LocalCount>,
    pub instructions: Vec<Instruction>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct CodeSection {
    pub code_blocks: Vec<CodeBlock>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct Export {
    pub name: String,
    pub index: usize,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
//#[serde(tag = "export_type", content = "content")]
#[repr(C)]
pub enum WasmExport {
    //#[serde(rename = "function")]
    Function(Export),
    //#[serde(rename = "table")]
    Table(Export),
    //#[serde(rename = "memory")]
    Memory(Export),
    //#[serde(rename = "global")]
    Global(Export),
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct ExportSection {
    pub exports: Vec<WasmExport>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct FunctionImport {
    pub module_name: String,
    pub name: String,
    pub type_index: usize,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct GlobalImport {
    pub module_name: String,
    pub name: String,
    pub value_type: ValueType,
    pub is_mutable: bool,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct MemoryImport {
    pub module_name: String,
    pub name: String,
    pub min_pages: usize,
    pub max_pages: Option<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct TableImport {
    pub module_name: String,
    pub name: String,
    pub element_type: u8,
    pub min: usize,
    pub max: Option<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[serde(tag = "import_type", content = "content")]
#[repr(C)]
pub enum WasmImport {
    //#[serde(rename = "function")]
    Function(FunctionImport),
    //#[serde(rename = "global")]
    Global(GlobalImport),
    //#[serde(rename = "memory")]
    Memory(MemoryImport),
    //#[serde(rename = "table")]
    Table(TableImport),
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct ImportSection {
    pub imports: Vec<WasmImport>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct WasmMemory {
    pub min_pages: usize,
    pub max_pages: Option<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct MemorySection {
    pub memories: Vec<WasmMemory>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct StartSection {
    pub start_function: usize,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct Global {
    pub value_type: ValueType,
    pub is_mutable: bool,
    pub value_expression: Vec<Instruction>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct GlobalSection {
    pub globals: Vec<Global>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct Table {
    pub element_type: u8,
    pub min: usize,
    pub max: Option<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct TableSection {
    pub tables: Vec<Table>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct DataBlock {
    pub memory: usize,
    pub offset_expression: Vec<Instruction>,
    pub data: Vec<u8>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct DataSection {
    pub data_blocks: Vec<DataBlock>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct CustomSection {
    pub name: String,
    pub data: Vec<u8>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct WasmElement {
    pub table: usize,
    pub value_expression: Vec<Instruction>,
    pub functions: Vec<usize>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[repr(C)]
pub struct ElementSection {
    pub elements: Vec<WasmElement>,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
#[serde(tag = "section_type", content = "content")]
#[repr(C)]
pub enum Section {
    //#[serde(rename = "type")]
    Type(TypeSection),
    //#[serde(rename = "function")]
    Function(FunctionSection),
    //#[serde(rename = "code")]
    Code(CodeSection),
    //#[serde(rename = "export")]
    Export(ExportSection),
    //#[serde(rename = "import")]
    Import(ImportSection),
    //#[serde(rename = "memory")]
    Memory(MemorySection),
    //#[serde(rename = "start")]
    Start(StartSection),
    //#[serde(rename = "global")]
    Global(GlobalSection),
    //#[serde(rename = "table")]
    Table(TableSection),
    //#[serde(rename = "data")]
    Data(DataSection),
    //#[serde(rename = "custom")]
    Custom(CustomSection),
    //#[serde(rename = "element")]
    Element(ElementSection),
}

impl Section {
    pub fn id(&self) -> u32 {
        match self {
            Section::Custom(_) => 0,
            Section::Type(_) => 1,
            Section::Import(_) => 2,
            Section::Function(_) => 3,
            Section::Table(_) => 4,
            Section::Memory(_) => 5,
            Section::Global(_) => 6,
            Section::Export(_) => 7,
            Section::Start(_) => 8,
            Section::Element(_) => 9,
            Section::Code(_) => 10,
            Section::Data(_) => 11,
        }
    }
}

pub trait WasmCompiler {
    fn compile(&mut self) -> Vec<u8>;
}

pub trait WriteWasm {
    fn extend_wasm_bytes(&self, v: &mut Vec<u8>);
}