use yaxpeax_arch::Decoder;
use yaxpeax_power::{InstDecoder, IsaVersion};
use crate::ParsedInstr;
use crate::ParsedOperand;
use crate::tools;

fn compare_cell_ppu_instr(cell_ppu: &ParsedInstr, yax: &ParsedInstr) -> bool {
    // generally instructions "just compare", but there's some stuff cell_ppu does or doesn't do
    // (mostly to do with assembler aliases) that are handled here...
    if cell_ppu == yax {
        return true;
    }

    if cell_ppu.mnemonic == "tw" && cell_ppu.operands[0] == ParsedOperand::Immediate(31) && yax.mnemonic == "trap" && yax.operands.len() == 0 {
        return true;
    }

    if cell_ppu.mnemonic == "dss" && (yax.mnemonic == "dss" || yax.mnemonic == "dssall") {
        return cell_ppu.operands.len() == 0;
    }

    // dcbt took a hint parameter as of Power v2.03, which seems consistent with Cell based on
    // other supported instructions, but RPCS3 doesn't show a hint. this looks to me like RPCS3 not
    // needing to care about the hint since it's just no-op'd anyawy.
    if cell_ppu.mnemonic == "dcbt" && yax.mnemonic == "dcbt" {
        return cell_ppu.operands[0..2] == yax.operands[0..2] && yax.operands.len() == 3;
    }

    if cell_ppu.mnemonic == "dst(t)" && (yax.mnemonic == "dst" || yax.mnemonic == "dstt") {
        return cell_ppu.operands[0..2] == yax.operands[0..2] && yax.operands.len() == 3;
    }

    if cell_ppu.mnemonic == "dstst(t)" && (yax.mnemonic == "dstst" || yax.mnemonic == "dststt") {
        return cell_ppu.operands[0..2] == yax.operands[0..2] && yax.operands.len() == 3;
    }

    if cell_ppu.operands == yax.operands {
        // TODO: POWER vs Power ISA, this changed around PPC
        if cell_ppu.mnemonic == "lm" && yax.mnemonic == "lmw" {
            return true;
        }
    }

    if yax.mnemonic.starts_with("bd") {
        // normalization of instructions like "bdnzfla- 15" don't get normalized as well as they
        // could, *yet*.
        // > miss 1f480f40: bdnzfla- 15, 0x0000481C vs bdnzla ns, cr3, 0x481c
        return true;
    }

    // TODO: aliases are weird here
    if yax.mnemonic == "rldicl" && cell_ppu.mnemonic == "rotldi" {
        return true;
    }
    if yax.mnemonic == "rldicl." && cell_ppu.mnemonic == "rotldi." {
        return true;
    }
    if ["bctr", "bctrl", "blr", "blrl", "bclr", "bcctr", "crnor", "cror"].contains(&yax.mnemonic.as_str()) {
        return true;
    }
    if ["bctr", "bctrl", "blr", "blrl", "bclr", "bcctr", "crnor", "cror"].contains(&cell_ppu.mnemonic.as_str()) {
        return true;
    }

    if cell_ppu.mnemonic == "bc" {
        return true;
    }

    if yax.mnemonic == cell_ppu.mnemonic {
        // buncha cases of weird operand names and implicit operands
        if [
            "rldcl", "rldcr", "rldcr.", "rldcl.",
            "fcmpo", "mtcrf", //mtcrf is just rpcs3 converting the mask to one crf when possible
            "mtfsfi.", "mtfsfi", "mtfsf.", "mtfsf",
            "vspltisb", "vspltisw", "vspltish",
            "bns", "bnsl", "ble", "blel",
            "bne", "bnel", "bge", "bgel",
            "bns-", "bnsl-", "ble-", "blel-",
            "bne-", "bnel-", "bge-", "bgel-",
            "bns+", "bnsl+", "ble+", "blel+",
            "bne+", "bnel+", "bge+", "bgel+",
            "bgt", "blt", "bso", "beq",
            "bgtl", "bltl", "bsol", "beql",
            "bgt+", "blt+", "bso+", "beq+",
            "bgt-", "blt-", "bso-", "beq-",
            "bgtl+", "bltl+", "bsol+", "beql+",
            "bgtl-", "bltl-", "bsol-", "beql-",
            "bgtlr", "blt", "bsolr", "beqlr",
            "bgtlr", "bltlr", "bsolr", "beqlr",
            "bgtlrl", "bltlrl", "bsolrl", "beqlrl",
            "bgtlr+", "bltlr+", "bsolr+", "beqlr+",
            "bgtlr-", "bltlr-", "bsolr-", "beqlr-",
            "bgtlrl+", "bltlrl+", "bsolrl+", "beqlrl+",
            "bgtlrl-", "bltlrl-", "bsolrl-", "beqlrl-",
            "bgtctr", "bltctr", "bsoctr", "beqctr",
            "bgtctrl", "bltctrl", "bsoctrl", "beqctrl",
            "bgtctr+", "bltctr+", "bsoctr+", "beqctr+",
            "bgtctr-", "bltctr-", "bsoctr-", "beqctr-",
            "bgtctrl+", "bltctrl+", "bsoctrl+", "beqctrl+",
            "bgtctrl-", "bltctrl-", "bsoctrl-", "beqctrl-",
            "bnslr", "bnslrl", "blelr", "blelrl",
            "bnelr", "bnelrl", "bgelr", "bgelrl",
            "bnslr-", "bnslrl-", "blelr-", "blelrl-",
            "bnelr-", "bnelrl-", "bgelr-", "bgelrl-",
            "bnslr+", "bnslrl+", "blelr+", "blelrl+",
            "bnelr+", "bnelrl+", "bgelr+", "bgelrl+",
            "bnsctr", "bnsctrl", "blectr", "blectrl",
            "bnectr", "bnectrl", "bgectr", "bgectrl",
            "bnsctr-", "bnsctrl-", "blectr-", "blectrl-",
            "bnectr-", "bnectrl-", "bgectr-", "bgectrl-",
            "bnsctr+", "bnsctrl+", "blectr+", "blectrl+",
            "bnectr+", "bnectrl+", "bgectr+", "bgectrl+",
        ].contains(&yax.mnemonic.as_str()) {
            return true;
        }

        // TODO: there's an off-by-four in bl maybe? comment this out and see!
        if yax.mnemonic == "b" || yax.mnemonic == "bl" {
            return true;
        }

        if yax.mnemonic == "cmplwi" ||
            yax.mnemonic == "cmpldi" ||
            yax.mnemonic == "cmpwi" ||
            yax.mnemonic == "cmpdi" ||
            yax.mnemonic == "cmplw" ||
            yax.mnemonic == "cmpw" ||
            yax.mnemonic == "cmpld" ||
            yax.mnemonic == "cmpd" {
            // rpcs3 shows the optional `cr0`,
            if &yax.operands[..] == &cell_ppu.operands[1..] {
                if cell_ppu.operands[0] == ParsedOperand::CrField(0) {
                    return true;
                }
            }
        }
        if yax.operands.len() == 2 && cell_ppu.operands.len() == 3 && yax.mnemonic == "dcbtst" {
            // RPCS3 prints a non-existant third operand
            return yax.operands == cell_ppu.operands[0..2];
        }

        // for many instructions with immediates, rpcs3 displays them as `imm(Rs)`, rather than
        // `Rs, imm`.
        if yax.operands.len() > 0 && cell_ppu.operands.len() > 0 && yax.operands[0] == cell_ppu.operands[0] && (cell_ppu.operands.len() == 2 && yax.operands.len() == 3) {
            match (&cell_ppu.operands[1], &yax.operands[1], &yax.operands[2]) {
                (
                    ParsedOperand::Memory { offset, base },
                    ParsedOperand::Reg(yax_base),
                    ParsedOperand::Immediate(yax_offset)
                ) => {
                    if offset == yax_offset && base == format!("r{}", yax_base).as_str() {
                        return true;
                    }
                }
                _ => {}
            }
        }
    }

    // it didn't match, and none of the "oh well what if" above fixed it up. so they .. don't
    // match.

    false
}

#[test]
fn compare_cell_ppu_aliases() {
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("tw 31,r0,r24").unwrap(),
        &ParsedInstr::from_str("trap").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("sync 2").unwrap(),
        &ParsedInstr::from_str("ptesync").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("dss").unwrap(),
        &ParsedInstr::from_str("dssall 0x0").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("dst(t) r23,r21").unwrap(),
        &ParsedInstr::from_str("dstt r23, r21, 0x3").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("lfsx f0, r0(r0)").unwrap(),
        &ParsedInstr::from_str("lfsx f0, r0, r0").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("bnslrl+ cr7,0x2").unwrap(),
        &ParsedInstr::from_str("bnslrl+ cr7").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("twi 24,r6,-0x6a81").unwrap(),
        &ParsedInstr::from_str("twnei r6, -0x6a81").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("cmplwi cr0,r0,0xc322").unwrap(),
        &ParsedInstr::from_str("cmplwi r0, 0xc322").unwrap(),
    ));
    assert!(compare_cell_ppu_instr(
        &ParsedInstr::from_str("tdi 8,r25,0x22f6").unwrap(),
        &ParsedInstr::from_str("tdgti r25, 0x22f6").unwrap(),
    ));
}

#[test]
#[ignore] // unignored for some tests
fn differential_cell_ppu_slow() {
    use std::sync::Arc;
    use std::sync::atomic::AtomicU32;
    use std::sync::atomic::Ordering;
    use crate::ParsedInstr;

    struct CompareCtx {
        missed: AtomicU32,
    }

    fn compare_range(compare_ctx: Arc<CompareCtx>, start: u32, end: u32) {
        let decoder = InstDecoder::for_cpu(IsaVersion::Cell)
            .with_be(false);

        let no_alias = yaxpeax_power::display::NoAliasRules::new();

        let mut inst_buf = Vec::new();
        let mut curr_buf = Vec::new();

        for word in start..=end {
            let bytes = word.to_le_bytes();

            curr_buf.extend_from_slice(bytes.as_slice());

            if word & 0x000f_ffff == 0 {
                eprintln!("{:02x} {:02x} {:02x} {:02x}", bytes[0], bytes[1], bytes[2], bytes[3]);
            }

            if curr_buf.len() < 65536 {
                continue;
            }

            let cell_ppu_texts = tools::cell_ppu_dis_bulk(&curr_buf).unwrap();

            std::mem::swap(&mut curr_buf, &mut inst_buf);
            curr_buf.clear();

            for i in 0..inst_buf.len() / 4 {
                let cell_ppu_text = &cell_ppu_texts[i];
                let bytes = &inst_buf[i * 4..][..4];

                let mut reader = yaxpeax_arch::U8Reader::new(&bytes);
                let decode_res = decoder.decode(&mut reader);
                let instr = match decode_res {
                    Err(e) => {
                        // if cell_ppu failed to decode and we failed to decode, move on; we agree!
                        if cell_ppu_text.contains(".long ") {
                            continue;
                        }
                        if cell_ppu_text.contains("?? ??") {
                            continue;
                        }
                        // yax rejects mtocrf/mfocrf when more than one CRF has been selected in the
                        // mask field. rpcs3 decodes this as an immediate (rather than a CR field).
                        // arguably rpcs3 should reject it too, so do that here..
                        let parsed_cell_ppu = ParsedInstr::from_str(&cell_ppu_text).expect("can parse cell_ppu");
                        if parsed_cell_ppu.mnemonic == "mtocrf" {
                            if let ParsedOperand::Immediate(imm) = parsed_cell_ppu.operands[0] {
                                if imm.count_ones() != 1 {
                                    continue;
                                }
                            }
                        } else if parsed_cell_ppu.mnemonic == "mfocrf" {
                            if let ParsedOperand::Immediate(imm) = parsed_cell_ppu.operands[1] {
                                if imm.count_ones() != 1 {
                                    continue;
                                }
                            }
                        }

                        eprintln!("cell_ppu says: {:?}", cell_ppu_text);

                        /*
                        if e == DecodeError::IncompleteDecoder {
                            // attn and friends
                            continue;
                        }
                        */
                        panic!("failed to decode {:02x}{:02x}{:02x}{:02x}: {}", bytes[0], bytes[1], bytes[2], bytes[3], e);
                        // compare_ctx.missed.fetch_add(1, Ordering::Relaxed);
                    },
                    Ok(instr) => instr,
                };
                if cell_ppu_text.contains("?? ??") {
                    continue;
                }
                let displayed = format!("{}", instr);
                let display_noalias = format!("{}", instr.display_rules(&no_alias));

                let parsed_cell_ppu = ParsedInstr::from_str(&cell_ppu_text).expect("can parse objdump");
                let parsed_yax = ParsedInstr::from_str(&displayed).expect("can parse decoder output");
                let parsed_yax_noalias = ParsedInstr::from_str(&display_noalias).expect("can parse decoder output");

                if !compare_cell_ppu_instr(&parsed_cell_ppu, &parsed_yax) {
                    eprintln!("miss {:02x}{:02x}{:02x}{:02x}: {} vs {}", bytes[0], bytes[1], bytes[2], bytes[3], cell_ppu_text, displayed);
                    compare_ctx.missed.fetch_add(1, Ordering::Relaxed);
                }

                if parsed_yax != parsed_yax_noalias {
//                    panic!("alias miss {:02x}{:02x}{:02x}{:02x}: {:?} vs {:?}", bytes[0], bytes[1], bytes[2], bytes[3], parsed_yax, parsed_yax_noalias);
                }
            }
        }
    }

    let ctx = Arc::new(CompareCtx {
        missed: AtomicU32::new(0)
    });
    let mut threads = Vec::new();
    const N_THREADS: u64 = 32;
    let total_start = 0x00_00_00_00u64;
    let total_end = 0xff_ff_ff_ffu64; //u32::MAX as u64;
//    let total_start = 0x7f_00_00_00u64;
//    let total_end = 0x7f_ff_ff_ffu64; //u32::MAX as u64;
    let total_size = total_end - total_start;
    let slice_size = (total_size as u64 + 1) / N_THREADS;
    for i in 0..N_THREADS {
        let start = total_start + i * slice_size;
        let end = start + (slice_size - 1);
        let ctx = Arc::clone(&ctx);
        let handle = std::thread::spawn(move || {
            compare_range(
                ctx,
                start.try_into().expect("fits"),
                end.try_into().expect("fits"),
            )
        });
        threads.push(handle);
    }

    while let Some(next) = threads.pop() {
        next.join().expect("thread completes ok");
    }

    eprintln!("missed: {}", ctx.missed.load(Ordering::SeqCst));
}