#![allow(dead_code, private_interfaces)]
use super::host_bridge::BoxInvokeFn;
use super::types::{LoadedPluginV2, NyashTypeBoxFfi, PluginBoxMetadata, PluginBoxV2, PluginHandleInner};
use crate::bid::{BidError, BidResult};
use crate::box_trait::NyashBox;
use crate::config::nyash_toml_v2::{LibraryDefinition, NyashConfigV2};
use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::sync::{Arc, RwLock};

use libloading::{Library, Symbol};

fn dbg_on() -> bool {
    std::env::var("NYASH_DEBUG_PLUGIN").unwrap_or_default() == "1"
}

// (alias imported from host_bridge)

#[derive(Debug, Clone, Default)]
pub(super) struct LoadedBoxSpec {
    pub(super) type_id: Option<u32>,
    pub(super) methods: HashMap<String, MethodSpec>,
    pub(super) fini_method_id: Option<u32>,
    // Optional Nyash ABI v2 per-box invoke entry (not yet used for calls)
    invoke_id: Option<BoxInvokeFn>,
    // Optional resolve(name)->method_id provided by NyashTypeBoxFfi
    pub(super) resolve_fn: Option<extern "C" fn(*const std::os::raw::c_char) -> u32>,
}
#[derive(Debug, Clone, Copy)]
pub(super) struct MethodSpec {
    pub(super) method_id: u32,
    returns_result: bool,
}

pub struct PluginLoaderV2 {
    pub(super) plugins: RwLock<HashMap<String, Arc<LoadedPluginV2>>>,
    pub config: Option<NyashConfigV2>,
    pub(super) config_path: Option<String>,
    pub(super) singletons: RwLock<HashMap<(String, String), Arc<PluginHandleInner>>>,
    pub(super) box_specs: RwLock<HashMap<(String, String), LoadedBoxSpec>>,
}

impl PluginLoaderV2 {
    pub fn new() -> Self {
        Self {
            plugins: RwLock::new(HashMap::new()),
            config: None,
            config_path: None,
            singletons: RwLock::new(HashMap::new()),
            box_specs: RwLock::new(HashMap::new()),
        }
    }

    pub fn load_config(&mut self, config_path: &str) -> BidResult<()> {
        let canonical = std::fs::canonicalize(config_path)
            .map(|p| p.to_string_lossy().to_string())
            .unwrap_or_else(|_| config_path.to_string());
        self.config_path = Some(canonical.clone());
        self.config =
            Some(NyashConfigV2::from_file(&canonical).map_err(|_| BidError::PluginError)?);
        if let Some(cfg) = self.config.as_ref() {
            let mut labels: Vec<String> = Vec::new();
            for (_lib, def) in &cfg.libraries {
                for bt in &def.boxes {
                    labels.push(format!("BoxRef:{}", bt));
                }
            }
            crate::runtime::cache_versions::bump_many(&labels);
        }
        Ok(())
    }

    pub fn load_all_plugins(&self) -> BidResult<()> {
        let config = self.config.as_ref().ok_or(BidError::PluginError)?;
        for (lib_name, lib_def) in &config.libraries {
            let _ = self.load_plugin(lib_name, lib_def);
        }
        for (plugin_name, root) in &config.plugins {
            let _ = self.load_plugin_from_root(plugin_name, root);
        }
        self.prebirth_singletons()?;
        Ok(())
    }

    fn load_plugin(&self, lib_name: &str, lib_def: &LibraryDefinition) -> BidResult<()> {
        // Resolve platform-specific filename from configured base path
        let base = Path::new(&lib_def.path);
        let mut candidates: Vec<PathBuf> = Vec::new();
        if cfg!(target_os = "windows") {
            // Try exact + .dll, and without leading 'lib'
            candidates.push(base.with_extension("dll"));
            if let Some(file) = base.file_name().and_then(|s| s.to_str()) {
                if file.starts_with("lib") {
                    let mut alt = base.to_path_buf();
                    let alt_file = file.trim_start_matches("lib");
                    alt.set_file_name(alt_file);
                    candidates.push(alt.with_extension("dll"));
                }
            }
        } else if cfg!(target_os = "macos") {
            candidates.push(base.with_extension("dylib"));
        } else {
            candidates.push(base.with_extension("so"));
        }

        // Prefer existing path; otherwise try to resolve via plugin_paths.search_paths
        let mut lib_path = candidates.iter().find(|p| p.exists()).cloned();
        if lib_path.is_none() {
            if let Some(cfg) = &self.config {
                // Try each candidate filename against search paths
                for c in &candidates {
                    if let Some(fname) = c.file_name().and_then(|s| s.to_str()) {
                        if let Some(resolved) = cfg.resolve_plugin_path(fname) {
                            let pb = PathBuf::from(resolved);
                            if pb.exists() {
                                lib_path = Some(pb);
                                break;
                            }
                        }
                    }
                }
            }
        }
        let lib_path = lib_path.unwrap_or_else(|| base.to_path_buf());
        if dbg_on() {
            eprintln!(
                "[PluginLoaderV2] load_plugin: lib='{}' path='{}'",
                lib_name,
                lib_path.display()
            );
        }
        let lib = unsafe { Library::new(&lib_path) }.map_err(|_| BidError::PluginError)?;
        let lib_arc = Arc::new(lib);

        // Optional init (best-effort)
        unsafe {
            if let Ok(init_sym) =
                lib_arc.get::<Symbol<unsafe extern "C" fn() -> i32>>(b"nyash_plugin_init\0")
            {
                let _ = init_sym();
            }
        }
        let loaded = LoadedPluginV2 {
            _lib: lib_arc.clone(),
            box_types: lib_def.boxes.clone(),
            typeboxes: HashMap::new(),
            init_fn: None,
        };
        self.plugins
            .write()
            .map_err(|_| BidError::PluginError)?
            .insert(lib_name.to_string(), Arc::new(loaded));

        // Try to resolve Nyash ABI v2 per-box TypeBox symbols and record invoke_id
        // Symbol pattern: nyash_typebox_<BoxType>
        for box_type in &lib_def.boxes {
            let sym_name = format!("nyash_typebox_{}\0", box_type);
            unsafe {
                if let Ok(tb_sym) = lib_arc.get::<Symbol<&NyashTypeBoxFfi>>(sym_name.as_bytes()) {
                    let st: &NyashTypeBoxFfi = &*tb_sym;
                    // Validate ABI tag 'TYBX' (0x54594258) and basic invariants
                    let abi_ok = st.abi_tag == 0x5459_4258
                        && st.struct_size as usize >= std::mem::size_of::<NyashTypeBoxFfi>();
                    if !abi_ok {
                        if dbg_on() {
                            eprintln!(
                                "[PluginLoaderV2] WARN: invalid TypeBox ABI for {}.{} (abi_tag=0x{:08x} size={} need>={})",
                                lib_name,
                                box_type,
                                st.abi_tag,
                                st.struct_size,
                                std::mem::size_of::<NyashTypeBoxFfi>()
                            );
                        }
                        continue;
                    }
                    // Remember invoke_id/resolve in box_specs for (lib_name, box_type)
                    if let Some(invoke_id) = st.invoke_id {
                        let key = (lib_name.to_string(), box_type.to_string());
                        let mut map = self.box_specs.write().map_err(|_| BidError::PluginError)?;
                        let entry = map.entry(key).or_insert(LoadedBoxSpec {
                            type_id: None,
                            methods: HashMap::new(),
                            fini_method_id: None,
                            invoke_id: None,
                            resolve_fn: None,
                        });
                        entry.invoke_id = Some(invoke_id);
                        entry.resolve_fn = st.resolve;
                    } else if dbg_on() {
                        eprintln!(
                            "[PluginLoaderV2] WARN: TypeBox present but no invoke_id for {}.{} — plugin should export per-Box invoke",
                            lib_name, box_type
                        );
                    }
                } else if dbg_on() {
                    eprintln!(
                        "[PluginLoaderV2] NOTE: TypeBox symbol not found for {}.{} (symbol='{}'). Migrate plugin to Nyash ABI v2 to enable per-Box dispatch.",
                        lib_name,
                        box_type,
                        sym_name.trim_end_matches('\0')
                    );
                }
            }
        }

        Ok(())
    }

    /// Public helper to load a single library definition directly (bypass nyash.toml sweep).
    /// Useful for `using kind="dylib"` autoload where only path and a few box names are known.
    pub fn load_plugin_direct(&self, lib_name: &str, lib_def: &LibraryDefinition) -> BidResult<()> {
        self.load_plugin(lib_name, lib_def)
    }

    fn load_plugin_from_root(&self, _plugin_name: &str, _root: &str) -> BidResult<()> {
        Ok(())
    }

    fn prebirth_singletons(&self) -> BidResult<()> {
        let config = self.config.as_ref().ok_or(BidError::PluginError)?;
        let cfg_path = self.config_path.as_deref().unwrap_or("nyash.toml");
        let toml_content = super::errors::from_fs(std::fs::read_to_string(cfg_path))?;
        let toml_value: toml::Value = super::errors::from_toml(toml::from_str(&toml_content))?;
        for (lib_name, lib_def) in &config.libraries {
            for box_name in &lib_def.boxes {
                if let Some(bc) = config.get_box_config(lib_name, box_name, &toml_value) {
                    if bc.singleton {
                        let _ = self.ensure_singleton_handle(lib_name, box_name);
                    }
                }
            }
        }
        Ok(())
    }

    fn find_box_by_type_id<'a>(
        &'a self,
        config: &'a NyashConfigV2,
        toml_value: &'a toml::Value,
        type_id: u32,
    ) -> Option<(&'a str, &'a str)> {
        for (lib_name, lib_def) in &config.libraries {
            for box_name in &lib_def.boxes {
                if let Some(box_conf) = config.get_box_config(lib_name, box_name, toml_value) {
                    if box_conf.type_id == type_id {
                        return Some((lib_name.as_str(), box_name.as_str()));
                    }
                }
            }
        }
        None
    }

    /// Lookup per-Box invoke function pointer for given type_id via loaded TypeBox specs
    pub fn box_invoke_fn_for_type_id(&self, type_id: u32) -> Option<BoxInvokeFn> {
        // First try config-based resolution
        if let (Some(config), Some(cfg_path)) = (self.config.as_ref(), self.config_path.as_ref()) {
            if let (Ok(toml_str), Ok(toml_value)) = (
                std::fs::read_to_string(cfg_path),
                toml::from_str::<toml::Value>(&std::fs::read_to_string(cfg_path).unwrap_or_default()),
            ) {
                let _ = toml_str; // silence
                if let Some((lib_name, box_type)) = self.find_box_by_type_id(config, &toml_value, type_id) {
                    let key = (lib_name.to_string(), box_type.to_string());
                    let map = self.box_specs.read().ok()?;
                    if let Some(s) = map.get(&key) {
                        if s.invoke_id.is_none() && dbg_on() {
                            eprintln!(
                                "[PluginLoaderV2] WARN: no per-Box invoke for {}.{} (type_id={}). Calls will fail with E_PLUGIN (-5) until plugin migrates to v2.",
                                lib_name, box_type, type_id
                            );
                        }
                        return s.invoke_id;
                    }
                }
            }
        }
        // Fallback: scan box_specs for matching type_id (autoload path without central config)
        if let Ok(map) = self.box_specs.read() {
            for ((_lib, _bt), spec) in map.iter() {
                if let Some(tid) = spec.type_id {
                    if tid == type_id {
                        return spec.invoke_id;
                    }
                }
            }
        }
        None
    }

    pub fn metadata_for_type_id(&self, type_id: u32) -> Option<PluginBoxMetadata> {
        let config = self.config.as_ref()?;
        let cfg_path = self.config_path.as_ref()?;
        let toml_str = std::fs::read_to_string(cfg_path).ok()?;
        let toml_value: toml::Value = toml::from_str(&toml_str).ok()?;
        let (lib_name, box_type) = self.find_box_by_type_id(config, &toml_value, type_id)?;
        let _plugin = {
            let plugins = self.plugins.read().ok()?;
            plugins.get(lib_name)?.clone()
        };
        let spec_key = (lib_name.to_string(), box_type.to_string());
        let mut resolved_type = type_id;
        let mut fini_method = None;
        if let Some(spec) = self.box_specs.read().ok()?.get(&spec_key).cloned() {
            if let Some(tid) = spec.type_id {
                resolved_type = tid;
            }
            if let Some(fini) = spec.fini_method_id {
                fini_method = Some(fini);
            }
        }
        if resolved_type == type_id || fini_method.is_none() {
            if let Some(cfg) = config.get_box_config(lib_name, box_type, &toml_value) {
                if resolved_type == type_id {
                    resolved_type = cfg.type_id;
                }
                if fini_method.is_none() {
                    fini_method = cfg.methods.get("fini").map(|m| m.method_id);
                }
            }
        }
        Some(PluginBoxMetadata {
            lib_name: lib_name.to_string(),
            box_type: box_type.to_string(),
            type_id: resolved_type,
            invoke_fn: super::super::nyash_plugin_invoke_v2_shim,
            fini_method_id: fini_method,
        })
    }

    pub fn construct_existing_instance(
        &self,
        type_id: u32,
        instance_id: u32,
    ) -> Option<Box<dyn NyashBox>> {
        let config = self.config.as_ref()?;
        let cfg_path = self.config_path.as_ref()?;
        let toml_str = std::fs::read_to_string(cfg_path).ok()?;
        let toml_value: toml::Value = toml::from_str(&toml_str).ok()?;
        let (lib_name, box_type) = self.find_box_by_type_id(config, &toml_value, type_id)?;
        let plugins = self.plugins.read().ok()?;
        let _plugin = plugins.get(lib_name)?.clone();
        let fini_method_id = if let Some(spec) = self
            .box_specs
            .read()
            .ok()?
            .get(&(lib_name.to_string(), box_type.to_string()))
        {
            spec.fini_method_id
        } else {
            let box_conf = config.get_box_config(lib_name, box_type, &toml_value)?;
            box_conf.methods.get("fini").map(|m| m.method_id)
        };
        let bx = super::types::construct_plugin_box(
            box_type.to_string(),
            type_id,
            super::super::nyash_plugin_invoke_v2_shim,
            instance_id,
            fini_method_id,
        );
        Some(Box::new(bx))
    }

    fn find_lib_name_for_box(&self, box_type: &str) -> Option<String> {
        if let Some(cfg) = &self.config {
            if let Some((name, _)) = cfg.find_library_for_box(box_type) {
                return Some(name.to_string());
            }
        }
        for ((lib, b), _) in self.box_specs.read().unwrap().iter() {
            if b == box_type {
                return Some(lib.clone());
            }
        }
        None
    }

    /// Best-effort: ingest specs from nyash_box.toml for autoloaded plugins.
    pub fn ingest_box_specs_from_nyash_box(
        &self,
        lib_name: &str,
        box_names: &[String],
        nyash_box_toml_path: &std::path::Path,
    ) {
        if !nyash_box_toml_path.exists() {
            return;
        }
        let Ok(text) = std::fs::read_to_string(nyash_box_toml_path) else { return; };
        let Ok(doc) = toml::from_str::<toml::Value>(&text) else { return; };
        if let Ok(mut map) = self.box_specs.write() {
            for box_type in box_names {
                let key = (lib_name.to_string(), box_type.to_string());
                let mut spec = map.get(&key).cloned().unwrap_or_default();
                // type_id
                if let Some(tid) = doc
                    .get(box_type)
                    .and_then(|v| v.get("type_id"))
                    .and_then(|v| v.as_integer())
                {
                    spec.type_id = Some(tid as u32);
                }
                // lifecycle.fini
                if let Some(fini) = doc
                    .get(box_type)
                    .and_then(|v| v.get("lifecycle"))
                    .and_then(|v| v.get("fini"))
                    .and_then(|v| v.get("id"))
                    .and_then(|v| v.as_integer())
                {
                    spec.fini_method_id = Some(fini as u32);
                }
                // lifecycle.birth (treat as method name "birth")
                if let Some(birth) = doc
                    .get(box_type)
                    .and_then(|v| v.get("lifecycle"))
                    .and_then(|v| v.get("birth"))
                    .and_then(|v| v.get("id"))
                    .and_then(|v| v.as_integer())
                {
                    spec.methods.insert(
                        "birth".to_string(),
                        MethodSpec { method_id: birth as u32, returns_result: false },
                    );
                }
                // methods.*.id
                if let Some(methods) = doc
                    .get(box_type)
                    .and_then(|v| v.get("methods"))
                    .and_then(|v| v.as_table())
                {
                    for (mname, mdef) in methods.iter() {
                        if let Some(id) = mdef
                            .get("id")
                            .and_then(|v| v.as_integer())
                            .map(|x| x as u32)
                        {
                            spec.methods.insert(
                                mname.to_string(),
                                MethodSpec { method_id: id, returns_result: mdef.get("returns_result").and_then(|v| v.as_bool()).unwrap_or(false) },
                            );
                        }
                    }
                }
                map.insert(key, spec);
            }
        }
    }

    fn ensure_singleton_handle(&self, lib_name: &str, box_type: &str) -> BidResult<()> {
        if self
            .singletons
            .read()
            .unwrap()
            .contains_key(&(lib_name.to_string(), box_type.to_string()))
        {
            return Ok(());
        }
        let cfg_path = self.config_path.as_deref().unwrap_or("nyash.toml");
        let toml_value: toml::Value =
            toml::from_str(&std::fs::read_to_string(cfg_path).map_err(|_| BidError::PluginError)?)
                .map_err(|_| BidError::PluginError)?;
        let config = self.config.as_ref().ok_or(BidError::PluginError)?;
        let plugins = self.plugins.read().unwrap();
        let _plugin = plugins.get(lib_name).ok_or(BidError::PluginError)?;
        let type_id = if let Some(spec) = self
            .box_specs
            .read()
            .unwrap()
            .get(&(lib_name.to_string(), box_type.to_string()))
        {
            spec.type_id
                .unwrap_or_else(|| config.box_types.get(box_type).copied().unwrap_or(0))
        } else {
            let box_conf = config
                .get_box_config(lib_name, box_type, &toml_value)
                .ok_or(BidError::InvalidType)?;
            box_conf.type_id
        };
        let out = vec![0u8; 1024];
        let out_len = out.len();
        let tlv_args = crate::runtime::plugin_ffi_common::encode_empty_args();
        let (birth_result, _len, out_vec) =
            super::host_bridge::invoke_alloc(super::super::nyash_plugin_invoke_v2_shim, type_id, 0, 0, &tlv_args);
        let out = out_vec;
        if birth_result != 0 || out_len < 4 {
            return Err(BidError::PluginError);
        }
        let instance_id = u32::from_le_bytes([out[0], out[1], out[2], out[3]]);
        let fini_id = if let Some(spec) = self
            .box_specs
            .read()
            .unwrap()
            .get(&(lib_name.to_string(), box_type.to_string()))
        {
            spec.fini_method_id
        } else {
            let box_conf = config
                .get_box_config(lib_name, box_type, &toml_value)
                .ok_or(BidError::InvalidType)?;
            box_conf.methods.get("fini").map(|m| m.method_id)
        };
        let handle = Arc::new(PluginHandleInner {
            type_id,
            invoke_fn: super::super::nyash_plugin_invoke_v2_shim,
            instance_id,
            fini_method_id: fini_id,
            finalized: std::sync::atomic::AtomicBool::new(false),
        });
        self.singletons
            .write()
            .unwrap()
            .insert((lib_name.to_string(), box_type.to_string()), handle);
        crate::runtime::cache_versions::bump_version(&format!("BoxRef:{}", box_type));
        Ok(())
    }

    pub fn extern_call(
        &self,
        iface_name: &str,
        method_name: &str,
        args: &[Box<dyn NyashBox>],
    ) -> BidResult<Option<Box<dyn NyashBox>>> {
        // Delegate to the extracted extern_functions module
        super::extern_functions::extern_call(iface_name, method_name, args)
    }
}