use std::fs::File;
use std::io::{Read, Write};
use std::{fmt, io};
use std::collections::BTreeSet;

fn main() {
    use clap::*;
    let _ = include_str!("../Cargo.toml");
    let app = app_from_crate!()
        .arg(
            Arg::with_name("arch")
                .short("a")
                .long("--architecture")
                .takes_value(true)
                .validator(|a| {
                    if ["x86_64", "x86_32", "x86_16",
                        "x86:64", "x86:32", "x86:16",
                        "ia64", "armv7", "armv8", "avr", "mips", "msp430",
                        "pic17", "pic18", "m16c", "6502", "lc87"].contains(&&a[..]) ||
                       (["sh", "sh2", "sh3", "sh4", "j2"].contains(
                             &&a[0..a.find(|c| c == '+' || c == '-').unwrap_or(a.len())]) &&
                        a.split(|c| c == '+' || c == '-').skip(1).all(
                            |f| ["be", "mmu", "fpu", "f64", "j2"].contains(&f))) {
                        Ok(())
                    } else {
                        Err("possible values: x86_64, x86_32, x86_16, x86:64, x86:32, x86:16, \
                                              ia64, armv7, armv8, avr, mips, msp430, pic17, pic18, \
                                              m16c, 6502, lc87, {sh{,2,3,4},j2}[[+-]{be,mmu,fpu,f64,j2}]*"
                            .to_string())
                    }
                })
                .help("architecture to disassemble input as."),
        )
        .arg(
            Arg::with_name("file")
                .short("f")
                .long("file")
                .takes_value(true)
                .help("file of bytes to decode"),
        )
        .arg(
            Arg::with_name("verbose")
                .short("v")
                .long("--verbose")
                .help("increased detail when decoding instructions"),
        )
        .arg(Arg::with_name("data").help(
            "hex bytes to decode by the selected architecture. for example, try -a x86_64 33c0c3",
        ));

    let matches = app.get_matches();

    let arch_str = matches.value_of("arch").unwrap_or("x86_64");
    let buf: Vec<u8> = match matches.value_of("data") {
        Some(data) => match hex::decode(data) {
            Ok(buf) => buf,
            Err(e) => {
                eprintln!("Invalid input, {}. Expected a sequence of bytes as hex", e);
                return;
            }
        },
        None => {
            let mut v = Vec::new();
            match matches.value_of("file") {
                Some(name) => match File::open(name) {
                    Ok(mut f) => {
                        f.read_to_end(&mut v).expect("can read the file");
                        v
                    }
                    Err(e) => {
                        eprintln!("error opening {}: {}", name, e);
                        return;
                    }
                },
                None => {
                    eprintln!("data must be provided by either an argument consisting of hex bytes, or by the --file argument.");
                    return;
                }
            }
        }
    };
    let verbose = matches.occurrences_of("verbose") > 0;

    let printer = Printer { stdout: io::stdout(), verbose };

    match arch_str {
        "x86_64" |
        "x86:64" => arch_02::decode_input::<yaxpeax_x86::long_mode::Arch>(&buf, &printer),
        "x86_32" |
        "x86:32" => arch_02::decode_input::<yaxpeax_x86::protected_mode::Arch>(&buf, &printer),
        "x86_16" |
        "x86:16" => arch_02::decode_input::<yaxpeax_x86::real_mode::Arch>(&buf, &printer),
        "ia64" => arch_02::decode_input::<yaxpeax_ia64::IA64>(&buf, &printer),
        "avr" => arch_02::decode_input::<yaxpeax_avr::AVR>(&buf, &printer),
        "armv7" => arch_02::decode_input::<yaxpeax_arm::armv7::ARMv7>(&buf, &printer),
        "armv8" => arch_02::decode_input::<yaxpeax_arm::armv8::a64::ARMv8>(&buf, &printer),
        "mips" => arch_02::decode_input::<yaxpeax_mips::MIPS>(&buf, &printer),
        "msp430" => arch_02::decode_input::<yaxpeax_msp430::MSP430>(&buf, &printer),
        "pic17" => arch_02::decode_input::<yaxpeax_pic17::PIC17>(&buf, &printer),
        "pic18" => arch_02::decode_input::<yaxpeax_pic18::PIC18>(&buf, &printer),
        "m16c" => arch_02::decode_input::<yaxpeax_m16c::M16C>(&buf, &printer),
        "6502" => arch_02::decode_input::<yaxpeax_6502::N6502>(&buf, &printer),
        "lc87" => arch_02::decode_input::<yaxpeax_lc87::LC87>(&buf, &printer),
        //        "pic24" => decode_input::<yaxpeax_pic24::PIC24>(buf),
        other => {
            let seg_idx = arch_str.find(|c| c == '+' || c == '-').unwrap_or(arch_str.len());
            let wps = |base| with_parsed_superh(base, &arch_str[seg_idx..],
                |decoder| arch_02::decode_input_with_decoder::<yaxpeax_superh::SuperH>(decoder, &buf, &printer));
            match &arch_str[0..seg_idx] {
                "sh" => wps(yaxpeax_superh::SuperHDecoder::SH1),
                "sh2" => wps(yaxpeax_superh::SuperHDecoder::SH2),
                "sh3" => wps(yaxpeax_superh::SuperHDecoder::SH3),
                "sh4" => wps(yaxpeax_superh::SuperHDecoder::SH4),
                "j2" => wps(yaxpeax_superh::SuperHDecoder::J2),
                _ => println!("unsupported architecture: {}", other),
            }
        }
    }
}

fn with_parsed_superh<F: FnOnce(yaxpeax_superh::SuperHDecoder)>(
    mut based_on: yaxpeax_superh::SuperHDecoder, mut from: &str, func: F
) {
    let mut features = based_on.features.iter().copied().collect::<BTreeSet<_>>();

    while !from.is_empty() {
        // This would be Not Trash if split_inclusive were stable; alas
        let op = from.chars().next().unwrap();
        from = &from[1..];

        let next_feat_idx = from.find(|c| c == '+' || c == '-').unwrap_or(from.len());
        let feat = &from[0..next_feat_idx];
        from = &from[next_feat_idx..];

        match (op, feat) {
            ('+', "be") => based_on.little_endian = false,
            ('-', "be") => based_on.little_endian = true,
            ('+', "f64") => based_on.fpscr_sz = true,
            ('-', "f64") => based_on.fpscr_sz = false,

            ('+', "mmu") => { features.insert(yaxpeax_superh::SuperHFeature::MMU); },
            ('-', "mmu") => { features.remove(&yaxpeax_superh::SuperHFeature::MMU); },
            ('+', "fpu") => { features.insert(yaxpeax_superh::SuperHFeature::FPU); },
            ('-', "fpu") => { features.remove(&yaxpeax_superh::SuperHFeature::FPU); },
            ('+', "j2") => { features.insert(yaxpeax_superh::SuperHFeature::J2); },
            ('-', "j2") => { features.remove(&yaxpeax_superh::SuperHFeature::J2); },

            pair => panic!("Who is {:?} and why was it not caught at parse time?", pair),
        }
    }

    func(yaxpeax_superh::SuperHDecoder {
        features: &features.into_iter().collect::<Vec<_>>()[..],
        ..based_on
    })
}

struct Printer {
    stdout: io::Stdout,
    verbose: bool,
}

impl Printer {
    // shared generic function to keep display logic consistent regardless of yaxpeax-arch version
    fn print_instr<I, E>(&self, rest: &[u8], addr: usize, x: Result<(usize, bool, I), E>)
    where
        I: fmt::Display + fmt::Debug,
        E: fmt::Display,
    {
        // TODO: lock stdout for the whole time? What if an arch implementation tries to log something?
        let mut stdout = self.stdout.lock();
        write!(stdout, "{:#010x}: ", addr).unwrap();
        match x {
            Ok((inst_len, well_defined, inst)) => {
                writeln!(stdout, "{:14}: {}", hex::encode(&rest[..inst_len]), inst)
                    .unwrap();
                if self.verbose {
                    writeln!(stdout, "  {:?}", inst).unwrap();
                    if !well_defined {
                        writeln!(stdout, "  not well-defined").unwrap();
                    }
                }
            }
            Err(e) => {
                writeln!(stdout, "{}", e).unwrap();
            }
        }
    }
}

// yaxpeax-arch, implemented by all decoders here, may be required at incompatible versions by
// different decoders if/when a new version releases. implement the actual decode-and-print
// behavior independent of yaxpeax-arch so decoders using different version can exist in parallel.
mod arch_02 {
    use super::Printer;
    use num_traits::identities::Zero;
    use std::fmt;
    use yaxpeax_arch_02::{
        AddressBase, Arch, Decoder, Instruction, LengthedInstruction, Reader, U8Reader,
    };

    pub(crate) fn decode_input<A: Arch>(buf: &[u8], printer: &Printer)
    where
        A::Instruction: fmt::Display,
        for<'data> U8Reader<'data>: Reader<A::Address, A::Word>,
    {
        decode_input_with_decoder::<A>(A::Decoder::default(), buf, printer);
    }

    pub(crate) fn decode_input_with_decoder<A: Arch>(
        decoder: A::Decoder,
        buf: &[u8],
        printer: &Printer,
    ) where
        A::Instruction: fmt::Display,
        for<'data> U8Reader<'data>: Reader<A::Address, A::Word>,
    {
        let mut addr = A::Address::zero();
        while let Some(rest) = buf.get(addr.to_linear()..).filter(|v| !v.is_empty()) {
            let mut reader = U8Reader::new(rest);
            let res = decoder.decode(&mut reader);
            let advance_addr = match &res {
                Ok(inst) => inst.len(),
                Err(_) => A::Instruction::min_size(),
            };
            let generic_res = res.map(|inst| {
                (
                    A::Address::zero().wrapping_offset(inst.len()).to_linear(),
                    inst.well_defined(),
                    inst,
                )
            });
            printer.print_instr(rest, addr.to_linear(), generic_res);
            addr += advance_addr;
        }
    }
}