//! The evmasm crate aims to provide a simple interface for the conversion between
//! evm bytecode and it's human readable form.
//!
//!```
//!extern crate evmasm;
//!use evmasm::{BYTE_INST, instruction, arguments_size};
//!
//!fn main() {
//!    for (&bc, _) in BYTE_INST.iter() {
//!        let inst = instruction(bc).ok().unwrap();
//!        println!("0x{:2x} - {} - needs {} bytes of arguments",
//!                 bc,
//!                 inst,
//!                 arguments_size(bc).ok().unwrap());
//!    }
//!}
//!```

#[macro_use]
extern crate lazy_static;

mod instructions;
pub use instructions::{BYTE_INST, INST_BYTE};

/// Error is only returned when an instruction/bytecode is not found
#[derive(Debug)]
pub enum Error<'a> {
    Bytecode(u8),
    Instruction(&'a str),
}

/// Return the bytecode corresponding to the provided instruction
pub fn bytecode<'a>(inst: &'a str) -> Result<u8, Error<'a>> {
    match INST_BYTE.get(inst) {
        Some(bc) => Ok(*bc),
        None => Err(Error::Instruction(inst)),
    }
}

/// Return the instruction corresponding to the provided bytecode
pub fn instruction<'a>(bytecode: u8) -> Result<&'static str, Error<'a>> {
    match BYTE_INST.get(&bytecode) {
        Some(i) => Ok(*i),
        None => Err(Error::Bytecode(bytecode)),
    }
}

/// Return the size in bytes of the arguments of a specific bytecode
pub fn arguments_size<'a>(bytecode: u8) -> Result<usize, Error<'a>> {
    if bytecode > 0x5f && bytecode < 0x80 {
        Ok((bytecode as usize) - 0x5f)
    } else if BYTE_INST.contains_key(&bytecode) {
        Ok(0)
    } else {
        Err(Error::Bytecode(bytecode))
    }
}

#[cfg(test)]
mod tests {
    use super::{instruction, bytecode, arguments_size};

    #[test]
    fn unknown_instruction() {
        if let Ok(_) = bytecode("hello world") {
            panic!("not an instruction");
        }
    }

    #[test]
    fn all_bytes() {
        let inst_bc: Vec<u8> =
            vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x10,
                 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x20, 0x30, 0x31,
                 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x40, 0x41,
                 0x42, 0x43, 0x44, 0x45, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
                 0x59, 0x5a, 0x5b, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
                 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96,
                 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3,
                 0xa4, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xff];
        let push_inst_bc: Vec<u8> = vec![0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
                                         0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71,
                                         0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
                                         0x7b, 0x7c, 0x7d, 0x7e, 0x7f];
        let push_inst_strs =
            vec!["PUSH1", "PUSH2", "PUSH3", "PUSH4", "PUSH5", "PUSH6", "PUSH7", "PUSH8", "PUSH9",
                 "PUSH10", "PUSH11", "PUSH12", "PUSH13", "PUSH14", "PUSH15", "PUSH16", "PUSH17",
                 "PUSH18", "PUSH19", "PUSH20", "PUSH21", "PUSH22", "PUSH23", "PUSH24", "PUSH25",
                 "PUSH26", "PUSH27", "PUSH28", "PUSH29", "PUSH30", "PUSH31", "PUSH32"];
        let inst_strs = vec!["STOP",
                             "ADD",
                             "MUL",
                             "SUB",
                             "DIV",
                             "SDIV",
                             "MOD",
                             "SMOD",
                             "ADDMOD",
                             "MULMOD",
                             "EXP",
                             "SIGNEXTEND",
                             "LT",
                             "GT",
                             "SLT",
                             "SGT",
                             "EQ",
                             "ISZERO",
                             "AND",
                             "OR",
                             "XOR",
                             "NOT",
                             "BYTE",
                             "SHA3",
                             "ADDRESS",
                             "BALANCE",
                             "ORIGIN",
                             "CALLER",
                             "CALLVALUE",
                             "CALLDATALOAD",
                             "CALLDATASIZE",
                             "CALLDATACOPY",
                             "CODESIZE",
                             "CODECOPY",
                             "TXGASPRICE",
                             "EXTCODESIZE",
                             "EXTCODECOPY",
                             "BLOCKHASH",
                             "COINBASE",
                             "TIMESTAMP",
                             "NUMBER",
                             "DIFFICULTY",
                             "GASLIMIT",
                             "POP",
                             "MLOAD",
                             "MSTORE",
                             "MSTORE8",
                             "SLOAD",
                             "SSTORE",
                             "JUMP",
                             "JUMPI",
                             "PC",
                             "MSIZE",
                             "GAS",
                             "JUMPDEST",
                             "DUP1",
                             "DUP2",
                             "DUP3",
                             "DUP4",
                             "DUP5",
                             "DUP6",
                             "DUP7",
                             "DUP8",
                             "DUP9",
                             "DUP10",
                             "DUP11",
                             "DUP12",
                             "DUP13",
                             "DUP14",
                             "DUP15",
                             "DUP16",
                             "SWAP1",
                             "SWAP2",
                             "SWAP3",
                             "SWAP4",
                             "SWAP5",
                             "SWAP6",
                             "SWAP7",
                             "SWAP8",
                             "SWAP9",
                             "SWAP10",
                             "SWAP11",
                             "SWAP12",
                             "SWAP13",
                             "SWAP14",
                             "SWAP15",
                             "SWAP16",
                             "LOG0",
                             "LOG1",
                             "LOG2",
                             "LOG3",
                             "LOG4",
                             "CREATE",
                             "CALL",
                             "CALLCODE",
                             "RETURN",
                             "DELEGATECALL",
                             "SUICIDE"];
        let seen = &mut [false; 256];
        let all_inst_bc = {
            let mut t = Vec::with_capacity(inst_bc.len() + push_inst_bc.len());
            t.extend(inst_bc.clone());
            t.extend(push_inst_bc);
            t
        };
        let all_inst_strs = {
            let mut t = Vec::with_capacity(inst_strs.len() + push_inst_strs.len());
            t.extend(inst_strs);
            t.extend(push_inst_strs);
            t
        };
        for i in all_inst_bc {
            if let Err(_) = instruction(i) {
                panic!("should be able to find an instruction");
            }
            seen[i as usize] = true;
        }
        for i in all_inst_strs {
            if let Err(_) = bytecode(i) {
                panic!("should be able to find a byte");
            }
        }
        for i in 0..256 {
            if seen[i] {
                continue;
            }
            if let Ok(_) = instruction(i as u8) {
                panic!(format!("should not find bytecode {}", i));
            }
        }
        for i in inst_bc {
            if arguments_size(i).ok().unwrap() != 0 {
                panic!("should get 0 as size");
            }
        }
        for i in 1..33 {
            let bc = (i as u8) + 0x5f;
            let sz = arguments_size(bc).ok().unwrap();
            if sz != i {
                panic!(format!("should get {} instead of {} (0x{:2x})", i, sz, bc));
            }
        }
    }
}