use serde_json::Value;
use std::collections::HashMap;

/// Minimal hv1 inline executor for tests (no Nyash parser).
/// Supports a very small subset needed by canaries:
/// - const i64
/// - mir_call(Constructor ArrayBox)
/// - mir_call(Method ArrayBox.push/size/len/length) with optional per-receiver state
/// - ret (by register id)
pub fn run_json_v1_inline(json: &str) -> i32 {
    // Parse JSON
    let v: Value = match serde_json::from_str(json) {
        Ok(v) => v,
        Err(_) => return 1,
    };
    // schema_version 1.x required
    match v.get("schema_version").and_then(Value::as_str) {
        Some(s) if s.starts_with('1') => {}
        _ => return 1,
    }
    // Fetch first function and build block map
    let functions = match v.get("functions").and_then(Value::as_array) { Some(a) => a, None => return 1 };
    let func = match functions.get(0) { Some(f) => f, None => return 1 };
    let blocks = match func.get("blocks").and_then(Value::as_array) { Some(a) => a, None => return 1 };
    let mut bmap: HashMap<i64, &Vec<Value>> = HashMap::new();
    for b in blocks {
        if let (Some(id), Some(insts)) = (b.get("id").and_then(Value::as_i64), b.get("instructions").and_then(Value::as_array)) {
            bmap.insert(id, insts);
        }
    }

    // Registers and simple method state
    let mut regs: HashMap<i64, i64> = HashMap::new();
    let sizestate = crate::config::env::env_bool("HAKO_VM_MIRCALL_SIZESTATE");
    let per_recv = crate::config::env::env_bool("HAKO_VM_MIRCALL_SIZESTATE_PER_RECV");
    // Keep Array and Map length states separate to avoid cross‑box interference
    let mut len_global_arr: i64 = 0;
    let mut len_by_recv_arr: HashMap<i64, i64> = HashMap::new();
    let mut len_global_map: i64 = 0;
    let mut len_by_recv_map: HashMap<i64, i64> = HashMap::new();

    fn is_size_alias(name: &str) -> bool {
        matches!(name, "size" | "len" | "length")
    }

    // Simple CFG interpreter with limited ops (const/compare/phi/branch/jump/mir_call/ret)
    let mut curr: i64 = 0; // assume entry block id 0
    let mut prev: i64 = -1;
    let mut steps: i32 = 0;
    'outer: loop {
        if steps > 10000 { return 1; }
        steps += 1;
        let insts = match bmap.get(&curr) { Some(v) => *v, None => return 1 };
        let mut ip = 0usize;
        while ip < insts.len() {
            let inst = &insts[ip];
            ip += 1;
            let op = match inst.get("op").and_then(Value::as_str) { Some(s) => s, None => return 1 };
        match op {
            "binop" => {
                // Minimal integer binops
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let lhs = inst.get("lhs").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let rhs = inst.get("rhs").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let opn = inst.get("operation").and_then(Value::as_str).unwrap_or("");
                let out = match opn {
                    "+" => lhs.wrapping_add(rhs),
                    "-" => lhs.wrapping_sub(rhs),
                    "*" => lhs.wrapping_mul(rhs),
                    "/" => {
                        if rhs == 0 { 0 } else { lhs.wrapping_div(rhs) }
                    }
                    "%" => {
                        if rhs == 0 { 0 } else { lhs.wrapping_rem(rhs) }
                    }
                    "&" => lhs & rhs,
                    "|" => lhs | rhs,
                    "^" => lhs ^ rhs,
                    "<<" => lhs.wrapping_shl((rhs as u32).min(63)),
                    ">>" => ((lhs as i64) >> (rhs as u32).min(63)) as i64,
                    _ => 0,
                };
                regs.insert(dst, out);
            }
            "unop" => {
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let src = inst.get("src").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let kind = inst.get("kind").and_then(Value::as_str).unwrap_or("");
                let out = match kind {
                    "neg" => src.wrapping_neg(),
                    "not" => if src == 0 { 1 } else { 0 },
                    "bitnot" => !src,
                    _ => 0,
                };
                regs.insert(dst, out);
            }
            "copy" => {
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let srcv = inst.get("src").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                regs.insert(dst, srcv);
            }
            "typeop" => {
                // Minimal TypeOp support for PRIMARY reps
                // Fields: operation ("check"|"is"|"cast"), src (vid), target_type (str), dst (vid)
                let operation = inst
                    .get("operation")
                    .and_then(Value::as_str)
                    .unwrap_or("")
                    .to_lowercase();
                let src = match inst.get("src").and_then(Value::as_i64) { Some(s) => s, None => return 1 };
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let target = inst
                    .get("target_type")
                    .and_then(Value::as_str)
                    .unwrap_or("")
                    .to_lowercase();

                let sval = regs.get(&src).cloned();
                let is_integer = sval.is_some(); // hv1 inline stores i64 only → integer
                let mut out = 0i64;
                if operation == "check" || operation == "is" {
                    if target == "i64" || target == "int" || target == "integer" {
                        out = if is_integer { 1 } else { 0 };
                    } else if target == "bool" {
                        // Inline model uses integer registers; treat 0/1 as bool when present
                        out = if let Some(v) = sval { if v == 0 || v == 1 { 1 } else { 0 } } else { 0 };
                    } else if target == "string" {
                        out = 0; // no string registers in inline model
                    } else {
                        out = 0;
                    }
                    regs.insert(dst, out);
                } else {
                    // cast/as: pass-through (MVP)
                    regs.insert(dst, sval.unwrap_or(0));
                }
            }
            "const" => {
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                // Prefer i64 numeric constants; otherwise stub non-numeric to 0 for inline path
                if let Some(n) = inst.get("value").and_then(|vv| vv.get("value")).and_then(Value::as_i64) {
                    regs.insert(dst, n);
                } else {
                    regs.insert(dst, 0);
                }
            }
            "compare" => {
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let lhs = inst.get("lhs").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let rhs = inst.get("rhs").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let cmp = inst.get("cmp").and_then(Value::as_str).unwrap_or("");
                let res = match cmp {
                    "Gt" => (lhs > rhs) as i64,
                    "Ge" => (lhs >= rhs) as i64,
                    "Lt" => (lhs < rhs) as i64,
                    "Le" => (lhs <= rhs) as i64,
                    "Eq" => (lhs == rhs) as i64,
                    "Ne" => (lhs != rhs) as i64,
                    _ => 0,
                };
                regs.insert(dst, res);
            }
            "mir_call" => {
                // Support both nested shape {"mir_call":{"callee":...}} and flat shape {"callee":...}
                let mc = inst.get("mir_call");
                let callee = if let Some(m) = mc { m.get("callee") } else { inst.get("callee") };
                let Some(callee) = callee else { return 1 };
                let ctype = callee.get("type").and_then(Value::as_str).unwrap_or("");
                match ctype {
                    // Constructor: just create and optionally write dst=0
                    "Constructor" => {
                        if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                        continue;
                    }
                    // ArrayBox methods we model inline
                    "Method" => {
                        let bname = callee.get("box_name").and_then(Value::as_str).unwrap_or("");
                        if bname == "ArrayBox" {
                            let method = callee.get("method").and_then(Value::as_str).unwrap_or("");
                            let recv = callee.get("receiver").and_then(Value::as_i64).unwrap_or(-1);
                            if method == "push" {
                                if sizestate {
                                    if per_recv {
                                        let e = len_by_recv_arr.entry(recv).or_insert(0);
                                        *e += 1;
                                    } else {
                                        len_global_arr += 1;
                                    }
                                }
                                if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                                continue;
                            }
                            if is_size_alias(method) {
                                let value = if sizestate {
                                    if per_recv { *len_by_recv_arr.get(&recv).unwrap_or(&0) } else { len_global_arr }
                                } else { 0 };
                                if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, value); }
                                continue;
                            }
                            // unsupported method on ArrayBox → stub 0
                            if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                            continue;
                        }
                        if bname == "MapBox" {
                            let method = callee.get("method").and_then(Value::as_str).unwrap_or("");
                            let recv = callee.get("receiver").and_then(Value::as_i64).unwrap_or(-1);
                            if method == "set" {
                                if sizestate {
                                    if per_recv {
                                        let e = len_by_recv_map.entry(recv).or_insert(0);
                                        *e += 1;
                                    } else {
                                        len_global_map += 1;
                                    }
                                }
                                if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                                continue;
                            }
                            if is_size_alias(method) {
                                let value = if sizestate {
                                    if per_recv { *len_by_recv_map.get(&recv).unwrap_or(&0) } else { len_global_map }
                                } else { 0 };
                                if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, value); }
                                continue;
                            }
                            // other methods stub 0
                            if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                            continue;
                        }
                        // Other box methods are not modeled; stub if dst present
                        if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                        continue;
                    }
                    // Extern calls: allow stub (return 0) when provider is enabled via env, else still stub to 0
                    "Extern" => {
                        let _provider_on = crate::config::env::env_bool("HAKO_V1_EXTERN_PROVIDER");
                        // For now, always treat extern as stub → write 0 when dst present
                        if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); }
                        continue;
                    }
                    _ => {}
                }
                // Unsupported callee shape/type → treat as stub if possible, else error
                if let Some(dst) = inst.get("dst").and_then(Value::as_i64) { regs.insert(dst, 0); continue; }
                return 1;
            }
            "phi" => {
                let dst = match inst.get("dst").and_then(Value::as_i64) { Some(d) => d, None => return 1 };
                let mut val: i64 = 0;
                let mut matched = false;
                if let Some(incomings) = inst.get("incoming").and_then(Value::as_array) {
                    for pair in incomings {
                        if let Some(arr) = pair.as_array() {
                            if arr.len() >= 2 {
                                // v1 schema (inline minimal): [value_reg, pred_block_id]
                                let r = arr[0].as_i64().unwrap_or(-1);
                                let b = arr[1].as_i64().unwrap_or(-1);
                                if b == prev { val = regs.get(&r).cloned().unwrap_or(0); matched = true; break; }
                            }
                        }
                    }
                }
                if !matched { return 1; }
                regs.insert(dst, val);
            }
            "branch" => {
                let cond = inst.get("cond").and_then(Value::as_i64).and_then(|r| regs.get(&r).cloned()).unwrap_or(0);
                let then_b = inst.get("then").and_then(Value::as_i64).unwrap_or(curr);
                let else_b = inst.get("else").and_then(Value::as_i64).unwrap_or(curr);
                prev = curr;
                curr = if cond != 0 { then_b } else { else_b };
                continue 'outer; // switch block
            }
            "jump" => {
                let target = inst.get("target").and_then(Value::as_i64).unwrap_or(curr);
                prev = curr;
                curr = target;
                continue 'outer; // switch block
            }
            "ret" => {
                let vid = match inst.get("value").and_then(Value::as_i64) { Some(v) => v, None => return 0 };
                let v = *regs.get(&vid).unwrap_or(&0);
                return (v as i32) & 0xFF;
            }
            // ignore others for now (compare/branch not used in hv1 per‑recv canaries)
            _ => {}
        }
        // if we completed a block without control flow, stop
        }
        return 0;
    }
}