use super::*;
use super::super::utils::*;
use serde_json::Value as JsonValue;

impl MirInterpreter {
    fn patch_mir_json_version(s: &str) -> String {
        match serde_json::from_str::<JsonValue>(s) {
            Ok(mut v) => {
                if let JsonValue::Object(ref mut m) = v {
                    if !m.contains_key("version") {
                        m.insert("version".to_string(), JsonValue::from(0));
                        if let Ok(out) = serde_json::to_string(&v) { return out; }
                    }
                }
                s.to_string()
            }
            Err(_) => s.to_string(),
        }
    }

    /// Central extern dispatcher used by both execute_extern_function (calls.rs)
    /// and handle_extern_call (externals.rs). Returns a VMValue; callers are
    /// responsible for writing it to registers when needed.
    pub(super) fn extern_provider_dispatch(
        &mut self,
        extern_name: &str,
        args: &[ValueId],
    ) -> Option<Result<VMValue, VMError>> {
        match extern_name {
            // Console family (minimal)
            "nyash.console.log" | "env.console.log" | "print" | "nyash.builtin.print" => {
                let s = if let Some(a0) = args.get(0) { self.reg_load(*a0).ok() } else { None };
                if let Some(v) = s { println!("{}", v.to_string()); } else { println!(""); }
                Some(Ok(VMValue::Void))
            }
            "env.console.warn" | "nyash.console.warn" => {
                let s = if let Some(a0) = args.get(0) { self.reg_load(*a0).ok() } else { None };
                if let Some(v) = s { eprintln!("[warn] {}", v.to_string()); } else { eprintln!("[warn]"); }
                Some(Ok(VMValue::Void))
            }
            "env.console.error" | "nyash.console.error" => {
                let s = if let Some(a0) = args.get(0) { self.reg_load(*a0).ok() } else { None };
                if let Some(v) = s { eprintln!("[error] {}", v.to_string()); } else { eprintln!("[error]"); }
                Some(Ok(VMValue::Void))
            }
            // Extern providers (env.mirbuilder / env.codegen)
            "env.mirbuilder.emit" => {
                // Guarded stub path for verify/Hakorune-primary bring-up
                if std::env::var("HAKO_V1_EXTERN_PROVIDER").ok().as_deref() == Some("1") {
                    return Some(Ok(VMValue::String(String::new())));
                }
                if args.is_empty() { return Some(Err(ErrorBuilder::arg_count_mismatch("env.mirbuilder.emit", 1, args.len()))); }
                let program_json = match self.reg_load(args[0]) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) };
                let res = match crate::host_providers::mir_builder::program_json_to_mir_json(&program_json) {
                    Ok(s) => Ok(VMValue::String(Self::patch_mir_json_version(&s))),
                    Err(e) => Err(ErrorBuilder::with_context("env.mirbuilder.emit", &e.to_string())),
                };
                Some(res)
            }
            "env.codegen.emit_object" => {
                // Guarded stub path for verify/Hakorune-primary bring-up
                if std::env::var("HAKO_V1_EXTERN_PROVIDER").ok().as_deref() == Some("1") {
                    return Some(Ok(VMValue::String(String::new())));
                }
                if args.is_empty() { return Some(Err(ErrorBuilder::arg_count_mismatch("env.codegen.emit_object", 1, args.len()))); }
                let mir_json_raw = match self.reg_load(args[0]) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) };
                // Normalize to v1 shape if missing/legacy (prevents harness NoneType errors)
                let mir_json = Self::patch_mir_json_version(&mir_json_raw);
                let opts = crate::host_providers::llvm_codegen::Opts {
                    out: None,
                    nyrt: std::env::var("NYASH_EMIT_EXE_NYRT").ok().map(std::path::PathBuf::from),
                    opt_level: std::env::var("HAKO_LLVM_OPT_LEVEL").ok().or(Some("0".to_string())),
                    timeout_ms: None,
                };
                let res = match crate::host_providers::llvm_codegen::mir_json_to_object(&mir_json, opts) {
                    Ok(p) => Ok(VMValue::String(p.to_string_lossy().into_owned())),
                    Err(e) => Err(ErrorBuilder::with_context("env.codegen.emit_object", &e.to_string())),
                };
                Some(res)
            }
            "env.codegen.link_object" => {
                // Only supported on C-API route; expect 1 or 2 args: obj_path [, exe_out]
                let obj_path = match args.get(0) {
                    Some(v) => match self.reg_load(*v) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) },
                    None => return Some(Err(VMError::InvalidInstruction("env.codegen.link_object expects 1+ args".into()))),
                };
                let exe_out = match args.get(1) {
                    Some(v) => Some(match self.reg_load(*v) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) }),
                    None => None,
                };
                let extra = std::env::var("HAKO_AOT_LDFLAGS").ok();
                // Require C-API toggles
                if std::env::var("NYASH_LLVM_USE_CAPI").ok().as_deref() != Some("1") ||
                   std::env::var("HAKO_V1_EXTERN_PROVIDER_C_ABI").ok().as_deref() != Some("1") {
                    return Some(Err(ErrorBuilder::invalid_instruction("env.codegen.link_object: C-API route disabled")));
                }
                let obj = std::path::PathBuf::from(obj_path);
                let exe = exe_out.map(std::path::PathBuf::from).unwrap_or_else(|| std::env::temp_dir().join("hako_link_out.exe"));
                match crate::host_providers::llvm_codegen::link_object_capi(&obj, &exe, extra.as_deref()) {
                    Ok(()) => Some(Ok(VMValue::String(exe.to_string_lossy().into_owned()))),
                    Err(e) => Some(Err(ErrorBuilder::with_context("env.codegen.link_object", &e.to_string()))),
                }
            }
            // Environment
            "env.get" => {
                if args.is_empty() { return Some(Err(ErrorBuilder::arg_count_mismatch("env.get", 1, args.len()))); }
                let key = match self.reg_load(args[0]) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) };
                let val = std::env::var(&key).ok();
                Some(Ok(match val { Some(s) => VMValue::String(s), None => VMValue::Void }))
            }
            // Legacy global-call form: hostbridge.extern_invoke(name, method, args?)
            "hostbridge.extern_invoke" => {
                if std::env::var("HAKO_CABI_TRACE").ok().as_deref() == Some("1") {
                    eprintln!("[hb:entry:provider] hostbridge.extern_invoke");
                }
                if args.len() < 2 {
                    return Some(Err(VMError::InvalidInstruction(
                        "extern_invoke expects at least 2 args".into(),
                    )));
                }
                let name = match self.reg_load(args[0]) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) };
                let method = match self.reg_load(args[1]) { Ok(v) => v.to_string(), Err(e) => return Some(Err(e)) };
                // Extract first payload arg (optional)
                let mut first_arg_str: Option<String> = None;
                if let Some(a2) = args.get(2) {
                    let v = match self.reg_load(*a2) { Ok(v) => v, Err(e) => return Some(Err(e)) };
                    match v {
                        VMValue::BoxRef(b) => {
                            if let Some(ab) = b.as_any().downcast_ref::<crate::boxes::array::ArrayBox>() {
                                let idx: Box<dyn crate::box_trait::NyashBox> =
                                    Box::new(crate::box_trait::IntegerBox::new(0));
                                let elem = ab.get(idx);
                                first_arg_str = Some(elem.to_string_box().value);
                            } else {
                                first_arg_str = Some(b.to_string_box().value);
                            }
                        }
                        _ => first_arg_str = Some(v.to_string()),
                    }
                }
                // Dispatch to known providers
                if std::env::var("HAKO_CABI_TRACE").ok().as_deref() == Some("1") {
                    eprintln!("[hb:dispatch:provider] {} {}", name, method);
                }
                let out = match (name.as_str(), method.as_str()) {
                    ("env.codegen", "link_object") if std::env::var("HAKO_CABI_TRACE").ok().as_deref() == Some("1") => {
                        // Trace payload shape before actual handling
                        if let Some(a2) = args.get(2) {
                            let v = match self.reg_load(*a2) { Ok(v) => v, Err(_) => VMValue::Void };
                            match &v {
                                VMValue::BoxRef(b) => {
                                    if b.as_any().downcast_ref::<crate::boxes::array::ArrayBox>().is_some() {
                                        eprintln!("[hb:provider:args] link_object third=ArrayBox");
                                    } else {
                                        eprintln!("[hb:provider:args] link_object third=BoxRef({})", b.type_name());
                                    }
                                }
                                other => {
                                    eprintln!("[hb:provider:args] link_object third={:?}", other);
                                }
                            }
                        } else {
                            eprintln!("[hb:provider:args] link_object third=<none>");
                        }
                        // fallthrough to real handler below by duplicating arm
                        // Args in third param (ArrayBox): [obj_path, exe_out?]
                        let (objs, exe_out) = if let Some(a2) = args.get(2) {
                            let v = match self.reg_load(*a2) {
                                Ok(v) => v,
                                Err(e) => return Some(Err(e)),
                            };
                            match v {
                                VMValue::BoxRef(b) => {
                                    if let Some(ab) = b.as_any().downcast_ref::<crate::boxes::array::ArrayBox>() {
                                        let idx0: Box<dyn crate::box_trait::NyashBox> = Box::new(crate::box_trait::IntegerBox::new(0));
                                        let elem0 = ab.get(idx0).to_string_box().value;
                                        let mut exe: Option<String> = None;
                                        let idx1: Box<dyn crate::box_trait::NyashBox> = Box::new(crate::box_trait::IntegerBox::new(1));
                                        let e1 = ab.get(idx1).to_string_box().value;
                                        if !e1.is_empty() { exe = Some(e1); }
                                        (elem0, exe)
                                    } else {
                                        (b.to_string_box().value, None)
                                    }
                                }
                                _ => (v.to_string(), None),
                            }
                        } else {
                            return Some(Err(VMError::InvalidInstruction("extern_invoke env.codegen.link_object expects args array".into())));
                        };
                        if std::env::var("NYASH_LLVM_USE_CAPI").ok().as_deref() != Some("1") ||
                           std::env::var("HAKO_V1_EXTERN_PROVIDER_C_ABI").ok().as_deref() != Some("1") {
                            return Some(Err(ErrorBuilder::invalid_instruction("env.codegen.link_object: C-API route disabled")));
                        }
                        let extra = std::env::var("HAKO_AOT_LDFLAGS").ok();
                        let obj = std::path::PathBuf::from(objs);
                        let exe = exe_out.map(std::path::PathBuf::from).unwrap_or_else(|| std::env::temp_dir().join("hako_link_out.exe"));
                        match crate::host_providers::llvm_codegen::link_object_capi(&obj, &exe, extra.as_deref()) {
                            Ok(()) => Ok(VMValue::String(exe.to_string_lossy().into_owned())),
                            Err(e) => Err(ErrorBuilder::with_context("env.codegen.link_object", &e.to_string()))
                        }
                    }
                    ("env.mirbuilder", "emit") => {
                        if let Some(s) = first_arg_str {
                            match crate::host_providers::mir_builder::program_json_to_mir_json(&s) {
                                Ok(out) => Ok(VMValue::String(Self::patch_mir_json_version(&out))),
                                Err(e) => Err(VMError::InvalidInstruction(format!(
                                    "env.mirbuilder.emit: {}",
                                    e
                                ))),
                            }
                        } else {
                            Err(VMError::InvalidInstruction(
                                "extern_invoke env.mirbuilder.emit expects 1 arg".into(),
                            ))
                        }
                    }
                    ("env.codegen", "emit_object") => {
                        if let Some(s) = first_arg_str {
                            let opts = crate::host_providers::llvm_codegen::Opts {
                                out: None,
                                nyrt: std::env::var("NYASH_EMIT_EXE_NYRT").ok().map(std::path::PathBuf::from),
                                opt_level: std::env::var("HAKO_LLVM_OPT_LEVEL").ok(),
                                timeout_ms: None,
                            };
                            match crate::host_providers::llvm_codegen::mir_json_to_object(&s, opts) {
                                Ok(p) => Ok(VMValue::String(p.to_string_lossy().into_owned())),
                                Err(e) => Err(VMError::InvalidInstruction(format!(
                                    "env.codegen.emit_object: {}",
                                    e
                                ))),
                            }
                        } else {
                            Err(VMError::InvalidInstruction(
                                "extern_invoke env.codegen.emit_object expects 1 arg".into(),
                            ))
                        }
                    }
                    ("env.codegen", "link_object") => {
                        // Unify both shapes:
                        // 1) third arg is ArrayBox [obj, exe?]
                        // 2) first_arg_str has obj and third arg has optional exe
                        let mut obj_s: Option<String> = None;
                        let mut exe_s: Option<String> = None;
                        if let Some(a2) = args.get(2) {
                            let v = match self.reg_load(*a2) {
                                Ok(v) => v,
                                Err(e) => return Some(Err(e)),
                            };
                            match v {
                                VMValue::BoxRef(b) => {
                                    if let Some(ab) = b.as_any().downcast_ref::<crate::boxes::array::ArrayBox>() {
                                        let idx0: Box<dyn crate::box_trait::NyashBox> = Box::new(crate::box_trait::IntegerBox::new(0));
                                        obj_s = Some(ab.get(idx0).to_string_box().value);
                                        let idx1: Box<dyn crate::box_trait::NyashBox> = Box::new(crate::box_trait::IntegerBox::new(1));
                                        let s1 = ab.get(idx1).to_string_box().value;
                                        if !s1.is_empty() { exe_s = Some(s1); }
                                    } else {
                                        obj_s = Some(b.to_string_box().value);
                                    }
                                }
                                _ => obj_s = Some(v.to_string()),
                            }
                        }
                        if obj_s.is_none() {
                            obj_s = first_arg_str;
                        }
                        let objs = match obj_s {
                            Some(s) => s,
                            None => return Some(Err(VMError::InvalidInstruction("extern_invoke env.codegen.link_object expects args".into()))),
                        };
                        if std::env::var("NYASH_LLVM_USE_CAPI").ok().as_deref() != Some("1") ||
                           std::env::var("HAKO_V1_EXTERN_PROVIDER_C_ABI").ok().as_deref() != Some("1") {
                            return Some(Err(ErrorBuilder::invalid_instruction("env.codegen.link_object: C-API route disabled")));
                        }
                        let extra = std::env::var("HAKO_AOT_LDFLAGS").ok();
                        let obj = std::path::PathBuf::from(objs);
                        let exe = exe_s.map(std::path::PathBuf::from).unwrap_or_else(|| std::env::temp_dir().join("hako_link_out.exe"));
                        match crate::host_providers::llvm_codegen::link_object_capi(&obj, &exe, extra.as_deref()) {
                            Ok(()) => Ok(VMValue::String(exe.to_string_lossy().into_owned())),
                            Err(e) => Err(ErrorBuilder::with_context("env.codegen.link_object", &e.to_string()))
                        }
                    }
                    _ => {
                        if std::env::var("HAKO_CABI_TRACE").ok().as_deref() == Some("1") {
                            eprintln!("[hb:unsupported:provider] {}.{}", name, method);
                        }
                        Err(VMError::InvalidInstruction(format!(
                            "hostbridge.extern_invoke unsupported for {}.{} [provider]",
                            name, method
                        )))
                    },
                };
                Some(out)
            }
            _ => None,
        }
    }
}