use crate::types::{
    FuncSig, GlobalDescriptor, MemoryDescriptor, MemoryIndex, TableDescriptor, TableIndex, Type,
};
use std::sync::Arc;
use wasmparser::BinaryReaderError;

pub type Result<T> = std::result::Result<T, Error>;
pub type CompileResult<T> = std::result::Result<T, CompileError>;
pub type LinkResult<T> = std::result::Result<T, Vec<LinkError>>;
pub type RuntimeResult<T> = std::result::Result<T, RuntimeError>;
pub type CallResult<T> = std::result::Result<T, CallError>;
pub type ResolveResult<T> = std::result::Result<T, ResolveError>;

/// This is returned when the chosen compiler is unable to
/// successfully compile the provided webassembly module into
/// a `Module`.
///
/// Comparing two `CompileError`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum CompileError {
    ValidationError { msg: String },
    InternalError { msg: String },
}

impl From<BinaryReaderError> for CompileError {
    fn from(other: BinaryReaderError) -> CompileError {
        CompileError::InternalError {
            msg: format!("{:?}", other),
        }
    }
}

impl PartialEq for CompileError {
    fn eq(&self, _other: &CompileError) -> bool {
        false
    }
}

/// This is returned when the runtime is unable to
/// correctly link the module with the provided imports.
///
/// Comparing two `LinkError`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum LinkError {
    IncorrectImportType {
        namespace: String,
        name: String,
        expected: String,
        found: String,
    },
    IncorrectImportSignature {
        namespace: String,
        name: String,
        expected: Arc<FuncSig>,
        found: Arc<FuncSig>,
    },
    ImportNotFound {
        namespace: String,
        name: String,
    },
    IncorrectMemoryDescriptor {
        namespace: String,
        name: String,
        expected: MemoryDescriptor,
        found: MemoryDescriptor,
    },
    IncorrectTableDescriptor {
        namespace: String,
        name: String,
        expected: TableDescriptor,
        found: TableDescriptor,
    },
    IncorrectGlobalDescriptor {
        namespace: String,
        name: String,
        expected: GlobalDescriptor,
        found: GlobalDescriptor,
    },
}

impl PartialEq for LinkError {
    fn eq(&self, _other: &LinkError) -> bool {
        false
    }
}

/// This is the error type returned when calling
/// a webassembly function.
///
/// The main way to do this is `Instance.call`.
///
/// Comparing two `RuntimeError`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum RuntimeError {
    OutOfBoundsAccess {
        memory: MemoryIndex,
        addr: Option<u32>,
    },
    TableOutOfBounds {
        table: TableIndex,
    },
    IndirectCallSignature {
        table: TableIndex,
    },
    IndirectCallToNull {
        table: TableIndex,
    },
    IllegalArithmeticOperation,
    User {
        msg: String,
    },
    Unknown {
        msg: String,
    },
}

impl PartialEq for RuntimeError {
    fn eq(&self, _other: &RuntimeError) -> bool {
        false
    }
}

/// This error type is produced by resolving a wasm function
/// given its name.
///
/// Comparing two `ResolveError`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum ResolveError {
    Signature {
        expected: Arc<FuncSig>,
        found: Vec<Type>,
    },
    ExportNotFound {
        name: String,
    },
    ExportWrongType {
        name: String,
    },
}

impl PartialEq for ResolveError {
    fn eq(&self, _other: &ResolveError) -> bool {
        false
    }
}

/// This error type is produced by calling a wasm function
/// exported from a module.
///
/// If the module traps in some way while running, this will
/// be the `CallError::Runtime(RuntimeError)` variant.
///
/// Comparing two `CallError`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum CallError {
    Resolve(ResolveError),
    Runtime(RuntimeError),
}

impl PartialEq for CallError {
    fn eq(&self, _other: &CallError) -> bool {
        false
    }
}

/// This error type is produced when creating something,
/// like a `Memory` or a `Table`.
#[derive(Debug, Clone)]
pub enum CreationError {
    UnableToCreateMemory,
    UnableToCreateTable,
}

impl PartialEq for CreationError {
    fn eq(&self, _other: &CreationError) -> bool {
        false
    }
}

/// The amalgamation of all errors that can occur
/// during the compilation, instantiation, or execution
/// of a webassembly module.
///
/// Comparing two `Error`s always evaluates to false.
#[derive(Debug, Clone)]
pub enum Error {
    CompileError(CompileError),
    LinkError(Vec<LinkError>),
    RuntimeError(RuntimeError),
    ResolveError(ResolveError),
    CallError(CallError),
    CreationError(CreationError),
}

impl PartialEq for Error {
    fn eq(&self, _other: &Error) -> bool {
        false
    }
}

impl From<CompileError> for Error {
    fn from(compile_err: CompileError) -> Self {
        Error::CompileError(compile_err)
    }
}

impl From<RuntimeError> for Error {
    fn from(runtime_err: RuntimeError) -> Self {
        Error::RuntimeError(runtime_err)
    }
}

impl From<ResolveError> for Error {
    fn from(resolve_err: ResolveError) -> Self {
        Error::ResolveError(resolve_err)
    }
}

impl From<CallError> for Error {
    fn from(call_err: CallError) -> Self {
        Error::CallError(call_err)
    }
}

impl From<CreationError> for Error {
    fn from(creation_err: CreationError) -> Self {
        Error::CreationError(creation_err)
    }
}

impl From<Vec<LinkError>> for Error {
    fn from(link_errs: Vec<LinkError>) -> Self {
        Error::LinkError(link_errs)
    }
}

impl From<RuntimeError> for CallError {
    fn from(runtime_err: RuntimeError) -> Self {
        CallError::Runtime(runtime_err)
    }
}

impl From<ResolveError> for CallError {
    fn from(resolve_err: ResolveError) -> Self {
        CallError::Resolve(resolve_err)
    }
}