//! Global environment configuration aggregator (管理棟)
//!
//! Consolidates NYASH_* environment variables across subsystems and
//! optionally applies overrides from `nyash.toml`.

use std::collections::BTreeMap;

#[derive(Debug, Clone, Default)]
pub struct NyashEnv {
    /// JIT-related configuration (delegates to jit::config)
    pub jit: crate::jit::config::JitConfig,
    /// Arbitrary key-value overrides loaded from nyash.toml [env]
    pub overrides: BTreeMap<String, String>,
}

impl NyashEnv {
    pub fn from_env() -> Self {
        Self {
            jit: crate::jit::config::JitConfig::from_env(),
            overrides: BTreeMap::new(),
        }
    }
    /// Apply current struct values into process environment
    pub fn apply_env(&self) {
        self.jit.apply_env();
        for (k, v) in &self.overrides {
            std::env::set_var(k, v);
        }
    }
}

// Global current env config (thread-safe)
use once_cell::sync::OnceCell;
use std::sync::RwLock;

static GLOBAL_ENV: OnceCell<RwLock<NyashEnv>> = OnceCell::new();
static PHI_ON_GATED_WARNED: OnceCell<()> = OnceCell::new();

pub fn current() -> NyashEnv {
    if let Some(lock) = GLOBAL_ENV.get() {
        if let Ok(cfg) = lock.read() {
            return cfg.clone();
        }
    }
    NyashEnv::from_env()
}

pub fn set_current(cfg: NyashEnv) {
    if let Some(lock) = GLOBAL_ENV.get() {
        if let Ok(mut w) = lock.write() {
            *w = cfg;
            return;
        }
    }
    let _ = GLOBAL_ENV.set(RwLock::new(cfg));
}

/// Load overrides from nyash.toml `[env]` table and apply them to process env.
///
/// Example:
/// [env]
/// NYASH_JIT_THRESHOLD = "1"
/// NYASH_CLI_VERBOSE = "1"
pub fn bootstrap_from_toml_env() {
    // Allow disabling nyash.toml env bootstrapping for isolated smokes/CI
    if std::env::var("NYASH_SKIP_TOML_ENV").ok().as_deref() == Some("1") {
        return;
    }
    let path = "nyash.toml";
    let content = match std::fs::read_to_string(path) {
        Ok(s) => s,
        Err(_) => return,
    };
    let Ok(value) = toml::from_str::<toml::Value>(&content) else {
        return;
    };
    let Some(env_tbl) = value.get("env").and_then(|v| v.as_table()) else {
        return;
    };
    let mut overrides: BTreeMap<String, String> = BTreeMap::new();
    for (k, v) in env_tbl {
        if let Some(s) = v.as_str() {
            std::env::set_var(k, s);
            overrides.insert(k.clone(), s.to_string());
        } else if let Some(b) = v.as_bool() {
            let sv = if b { "1" } else { "0" };
            std::env::set_var(k, sv);
            overrides.insert(k.clone(), sv.to_string());
        } else if let Some(n) = v.as_integer() {
            let sv = n.to_string();
            std::env::set_var(k, &sv);
            overrides.insert(k.clone(), sv);
        }
    }
    // Merge into global
    let mut cur = current();
    cur.overrides.extend(overrides);
    set_current(cur);
}

/// Get await maximum milliseconds, centralized here for consistency.
pub fn await_max_ms() -> u64 {
    std::env::var("NYASH_AWAIT_MAX_MS")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(5000)
}

// ---- MIR PHI-less (edge-copy) mode ----
/// Enable MIR PHI non-generation. Bridge/Builder emit edge copies instead of PHI.
pub fn mir_no_phi() -> bool {
    match std::env::var("NYASH_MIR_NO_PHI").ok() {
        Some(v) => {
            let lv = v.to_ascii_lowercase();
            let requested_no_phi = !(lv == "0" || lv == "false" || lv == "off");
            if requested_no_phi {
                return true;
            }
            // PHI-on requested
            #[cfg(feature = "phi-legacy")]
            {
                return false;
            }
            #[cfg(not(feature = "phi-legacy"))]
            {
                if PHI_ON_GATED_WARNED.set(()).is_ok() {
                    eprintln!(
                        "[nyash] PHI-on requested but disabled in this build (missing 'phi-legacy' feature). Falling back to PHI-off."
                    );
                }
                return true;
            }
        }
        // Default: ON for MIR13 stability (PHI generation off by default)
        None => true,
    }
}

/// Allow verifier to skip SSA/dominance/merge checks for PHI-less MIR.
pub fn verify_allow_no_phi() -> bool {
    std::env::var("NYASH_VERIFY_ALLOW_NO_PHI").ok().as_deref() == Some("1") || mir_no_phi()
}

/// Enable strict edge-copy policy verification in PHI-off mode.
/// When enabled, merge blocks must receive merged values via predecessor copies only,
/// and the merge block itself must not introduce a self-copy to the merged destination.
pub fn verify_edge_copy_strict() -> bool {
    std::env::var("NYASH_VERIFY_EDGE_COPY_STRICT").ok().as_deref() == Some("1")
}

// ---- LLVM harness toggle (llvmlite) ----
pub fn llvm_use_harness() -> bool {
    std::env::var("NYASH_LLVM_USE_HARNESS").ok().as_deref() == Some("1")
}

// ---- Phase 11.8 MIR cleanup toggles ----
/// Core-13 minimal MIR mode toggle
/// Default: ON (unless explicitly disabled with NYASH_MIR_CORE13=0)
pub fn mir_core13() -> bool {
    match std::env::var("NYASH_MIR_CORE13").ok() {
        Some(v) => {
            let lv = v.to_ascii_lowercase();
            !(lv == "0" || lv == "false" || lv == "off")
        }
        None => true,
    }
}
pub fn mir_ref_boxcall() -> bool {
    std::env::var("NYASH_MIR_REF_BOXCALL").ok().as_deref() == Some("1") || mir_core13()
}
pub fn mir_array_boxcall() -> bool {
    std::env::var("NYASH_MIR_ARRAY_BOXCALL").ok().as_deref() == Some("1") || mir_core13()
}
pub fn mir_plugin_invoke() -> bool {
    std::env::var("NYASH_MIR_PLUGIN_INVOKE").ok().as_deref() == Some("1")
}
pub fn plugin_only() -> bool {
    std::env::var("NYASH_PLUGIN_ONLY").ok().as_deref() == Some("1")
}

/// Core-13 "pure" mode: after normalization, only the 13 canonical ops are allowed.
/// If enabled, the optimizer will try lightweight rewrites for Load/Store/NewBox/Unary,
/// and the final verifier will reject any remaining non-Core-13 ops.
pub fn mir_core13_pure() -> bool {
    std::env::var("NYASH_MIR_CORE13_PURE").ok().as_deref() == Some("1")
}

// ---- Optimizer diagnostics ----
pub fn opt_debug() -> bool {
    std::env::var("NYASH_OPT_DEBUG").is_ok()
}
pub fn opt_diag() -> bool {
    std::env::var("NYASH_OPT_DIAG").is_ok()
}
pub fn opt_diag_forbid_legacy() -> bool {
    std::env::var("NYASH_OPT_DIAG_FORBID_LEGACY").is_ok()
}
pub fn opt_diag_fail() -> bool {
    std::env::var("NYASH_OPT_DIAG_FAIL").is_ok()
}

// ---- GC/Runtime tracing (execution-affecting visibility) ----
pub fn gc_trace() -> bool {
    std::env::var("NYASH_GC_TRACE").ok().as_deref() == Some("1")
}
pub fn gc_barrier_trace() -> bool {
    std::env::var("NYASH_GC_BARRIER_TRACE").ok().as_deref() == Some("1")
}
pub fn runtime_checkpoint_trace() -> bool {
    std::env::var("NYASH_RUNTIME_CHECKPOINT_TRACE")
        .ok()
        .as_deref()
        == Some("1")
}
pub fn vm_pic_stats() -> bool {
    std::env::var("NYASH_VM_PIC_STATS").ok().as_deref() == Some("1")
}
pub fn vm_vt_trace() -> bool {
    std::env::var("NYASH_VM_VT_TRACE").ok().as_deref() == Some("1")
}
pub fn vm_pic_trace() -> bool {
    std::env::var("NYASH_VM_PIC_TRACE").ok().as_deref() == Some("1")
}
pub fn gc_barrier_strict() -> bool {
    std::env::var("NYASH_GC_BARRIER_STRICT").ok().as_deref() == Some("1")
}

/// Return 0 (off) to 3 (max) for `NYASH_GC_TRACE`.
pub fn gc_trace_level() -> u8 {
    match std::env::var("NYASH_GC_TRACE").ok().as_deref() {
        Some("1") => 1,
        Some("2") => 2,
        Some("3") => 3,
        Some(_) => 1,
        None => 0,
    }
}

// ---- GC mode and instrumentation ----
/// Return current GC mode string (auto default = "rc+cycle").
/// Allowed: "auto", "rc+cycle", "minorgen", "stw", "rc", "off"
pub fn gc_mode() -> String {
    match std::env::var("NYASH_GC_MODE").ok() {
        Some(m) if !m.trim().is_empty() => m,
        _ => "rc+cycle".to_string(),
    }
}
/// Brief metrics emission (text)
pub fn gc_metrics() -> bool {
    std::env::var("NYASH_GC_METRICS").ok().as_deref() == Some("1")
}
/// JSON metrics emission (single line)
pub fn gc_metrics_json() -> bool {
    std::env::var("NYASH_GC_METRICS_JSON").ok().as_deref() == Some("1")
}
/// Leak diagnostics on exit
pub fn gc_leak_diag() -> bool {
    std::env::var("NYASH_GC_LEAK_DIAG").ok().as_deref() == Some("1")
}
/// Optional allocation threshold; if Some(n) and exceeded, print warning
pub fn gc_alloc_threshold() -> Option<u64> {
    std::env::var("NYASH_GC_ALLOC_THRESHOLD").ok()?.parse().ok()
}

// ---- Cleanup (method-level postfix) policy toggles ----
/// Allow `return` inside a cleanup block. Default: false (0)
pub fn cleanup_allow_return() -> bool {
    match std::env::var("NYASH_CLEANUP_ALLOW_RETURN").ok() {
        Some(v) => {
            let lv = v.to_ascii_lowercase();
            !(lv == "0" || lv == "false" || lv == "off")
        }
        None => false,
    }
}

/// Allow `throw` inside a cleanup block. Default: false (0)
pub fn cleanup_allow_throw() -> bool {
    match std::env::var("NYASH_CLEANUP_ALLOW_THROW").ok() {
        Some(v) => {
            let lv = v.to_ascii_lowercase();
            !(lv == "0" || lv == "false" || lv == "off")
        }
        None => false,
    }
}

/// Run a collection every N safepoints (if Some)
pub fn gc_collect_sp_interval() -> Option<u64> {
    std::env::var("NYASH_GC_COLLECT_SP").ok()?.parse().ok()
}
/// Run a collection when allocated bytes since last >= N (if Some)
pub fn gc_collect_alloc_bytes() -> Option<u64> {
    std::env::var("NYASH_GC_COLLECT_ALLOC").ok()?.parse().ok()
}

// ---- Rewriter flags (optimizer transforms)
pub fn rewrite_debug() -> bool {
    std::env::var("NYASH_REWRITE_DEBUG").ok().as_deref() == Some("1")
}
pub fn rewrite_safepoint() -> bool {
    std::env::var("NYASH_REWRITE_SAFEPOINT").ok().as_deref() == Some("1")
}
pub fn rewrite_future() -> bool {
    std::env::var("NYASH_REWRITE_FUTURE").ok().as_deref() == Some("1")
}

// ---- Phase 12: Nyash ABI (vtable) toggles ----
pub fn abi_vtable() -> bool {
    std::env::var("NYASH_ABI_VTABLE").ok().as_deref() == Some("1")
}
pub fn abi_strict() -> bool {
    std::env::var("NYASH_ABI_STRICT").ok().as_deref() == Some("1")
}

// ---- ExternCall strict diagnostics ----
pub fn extern_strict() -> bool {
    std::env::var("NYASH_EXTERN_STRICT").ok().as_deref() == Some("1")
}
pub fn extern_trace() -> bool {
    std::env::var("NYASH_EXTERN_TRACE").ok().as_deref() == Some("1")
}

// ---- Phase 12: thresholds and routing policies ----
/// PIC hotness threshold before promoting to mono cache.
pub fn vm_pic_threshold() -> u32 {
    std::env::var("NYASH_VM_PIC_THRESHOLD")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(8)
}

/// Route VM ExternCall via name→slot handlers when available
pub fn extern_route_slots() -> bool {
    std::env::var("NYASH_EXTERN_ROUTE_SLOTS").ok().as_deref() == Some("1")
}

// ---- Runner/CLI common toggles (hot-path centralization)
pub fn cli_verbose() -> bool {
    std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1")
}
pub fn enable_using() -> bool {
    std::env::var("NYASH_ENABLE_USING").ok().as_deref() == Some("1")
}
pub fn vm_use_py() -> bool {
    std::env::var("NYASH_VM_USE_PY").ok().as_deref() == Some("1")
}
pub fn pipe_use_pyvm() -> bool {
    std::env::var("NYASH_PIPE_USE_PYVM").ok().as_deref() == Some("1")
}
pub fn vm_use_dispatch() -> bool {
    std::env::var("NYASH_VM_USE_DISPATCH").ok().as_deref() == Some("1")
}

// Self-host compiler knobs
pub fn ny_compiler_timeout_ms() -> u64 {
    std::env::var("NYASH_NY_COMPILER_TIMEOUT_MS")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(2000)
}
pub fn ny_compiler_emit_only() -> bool {
    std::env::var("NYASH_NY_COMPILER_EMIT_ONLY").unwrap_or_else(|_| "1".to_string()) == "1"
}
pub fn ny_compiler_skip_py() -> bool {
    std::env::var("NYASH_NY_COMPILER_SKIP_PY").ok().as_deref() == Some("1")
}
pub fn use_ny_compiler_exe() -> bool {
    std::env::var("NYASH_USE_NY_COMPILER_EXE").ok().as_deref() == Some("1")
}
pub fn ny_compiler_exe_path() -> Option<String> {
    std::env::var("NYASH_NY_COMPILER_EXE_PATH").ok()
}
pub fn ny_compiler_min_json() -> bool {
    std::env::var("NYASH_NY_COMPILER_MIN_JSON").ok().as_deref() == Some("1")
}
pub fn selfhost_read_tmp() -> bool {
    std::env::var("NYASH_SELFHOST_READ_TMP").ok().as_deref() == Some("1")
}
pub fn ny_compiler_stage3() -> bool {
    std::env::var("NYASH_NY_COMPILER_STAGE3").ok().as_deref() == Some("1")
}
/// Core (Rust) parser Stage-3 gate
/// When enabled, the Rust parser accepts Stage-3 surface (try/catch/finally, throw).
/// Default is OFF to keep Stage-2 stable.
pub fn parser_stage3() -> bool {
    std::env::var("NYASH_PARSER_STAGE3").ok().as_deref() == Some("1")
}

/// Parser gate for Block‑Postfix Catch acceptance
/// Enabled when either NYASH_BLOCK_CATCH=1 or Stage‑3 gate is on.
/// Phase 15.5 allows parsing a standalone `{ ... }` block optionally followed by
/// a single `catch (...) { ... }` and/or `finally { ... }`, which is folded into
/// ASTNode::TryCatch with the preceding block as the try body.
pub fn block_postfix_catch() -> bool {
    std::env::var("NYASH_BLOCK_CATCH").ok().as_deref() == Some("1") || parser_stage3()
}

/// Bridge lowering: use Result-style try/throw lowering instead of MIR Catch/Throw
/// When on, try/catch is lowered using structured blocks and direct jumps,
/// without emitting MIR Throw/Catch. The thrown value is routed to catch via
/// block parameters (PHI-off uses edge-copy).
pub fn try_result_mode() -> bool {
    std::env::var("NYASH_TRY_RESULT_MODE").ok().as_deref() == Some("1")
}

/// Parser gate for method-level postfix catch/finally acceptance on method definitions.
/// Enabled when either NYASH_METHOD_CATCH=1 or Stage‑3 gate is on.
pub fn method_catch() -> bool {
    std::env::var("NYASH_METHOD_CATCH").ok().as_deref() == Some("1") || parser_stage3()
}

/// Entry policy: allow top-level `main` resolution in addition to `Main.main`.
/// Default: false (prefer explicit `static box Main { main(...) }`).
pub fn entry_allow_toplevel_main() -> bool {
    match std::env::var("NYASH_ENTRY_ALLOW_TOPLEVEL_MAIN").ok() {
        Some(v) => {
            let v = v.to_ascii_lowercase();
            v == "1" || v == "true" || v == "on"
        }
        None => false,
    }
}

/// Parser gate for expression-level postfix catch/cleanup acceptance.
/// Enabled when Stage-3 gate is on (NYASH_PARSER_STAGE3=1). Separate gate can
/// be introduced in future if needed, but we keep minimal toggles now.
pub fn expr_postfix_catch() -> bool {
    parser_stage3()
}
/// Parser gate for Unified Members (stored/computed/once/birth_once).
/// Default: ON during Phase-15 (set NYASH_ENABLE_UNIFIED_MEMBERS=0|false|off to disable).
pub fn unified_members() -> bool {
    match std::env::var("NYASH_ENABLE_UNIFIED_MEMBERS").ok() {
        Some(v) => {
            let lv = v.to_ascii_lowercase();
            !(lv == "0" || lv == "false" || lv == "off")
        }
        None => true,
    }
}
pub fn ny_compiler_child_args() -> Option<String> {
    std::env::var("NYASH_NY_COMPILER_CHILD_ARGS").ok()
}
pub fn ny_compiler_use_tmp_only() -> bool {
    std::env::var("NYASH_NY_COMPILER_USE_TMP_ONLY")
        .ok()
        .as_deref()
        == Some("1")
}