use std::collections::HashMap;

use crate::ast::Expr;

use super::entry::{Symbol, SymbolKind};

#[derive(Debug, Clone, Default)]

pub struct SymbolTable {

    pub(super) symbols: HashMap<String, Symbol>,

    pub(super) struct_fields: HashMap<String, Vec<String>>,

    /// Registered nomiscript tests, in declaration order. Populated

    /// by `DEFTEST`, drained by `RUN-TESTS`. Each entry is

    /// `(name, body)` where `body` is the test's wrapped (BEGIN ...)

    /// form. Lives on the table so each compiler/evaluator instance

    /// gets its own isolated registry — no global state.

    pub(super) tests: Vec<(String, Expr)>,

    /// Per-native-fn compile-time reference counter. Bumped each time

    /// the compiler emits a `call $<host-fn-idx>` for a registered

    /// `HostFnSpec`. Read by `(coverage-dump)` to certify the test

    /// surface reaches every native. Compile-time count (not runtime

    /// hits) — sufficient for the parity contract "every native has

    /// at least one test that compiles against it"; runtime hit

    /// counts via a wasm-global counter array land in a follow-up.

    pub(super) native_coverage: HashMap<String, u32>,

    /// Current macro-expansion nesting depth. Bumped on entry to each

    /// `expand_macro` (which clones the table for the expansion body), so

    /// the count accumulates down a chain of nested expansions and a

    /// self-referential macro is caught before it overflows the stack.

    /// Lives on the table because every expansion site threads

    /// `&mut SymbolTable`; a top-level form starts at 0.

    pub(super) macro_depth: usize,

    /// Names of defuns currently being inlined on the eval path, in entry

    /// order. The eval-side `call_lambda` walks a defun body inline for

    /// constant folding; a recursive defun whose recursion doesn't fold to a

    /// base case (e.g. a runtime-arg call) would otherwise recurse the

    /// compiler's native stack forever. A name already on this stack signals

    /// re-entry, so the call site short-circuits to a runtime placeholder

    /// (handing the real lowering to the codegen monomorph path) rather than

    /// inlining again. Threaded on the table because the eval path only ever

    /// carries `&mut SymbolTable`.

    pub(super) inline_stack: Vec<String>,

    /// Result `WasmType` of each emitted closure, keyed by `ClosureSigId`'s raw

    /// id. A closure value carries only `WasmType::Closure(sig)` — the sig's

    /// param/result types live on the codegen `CompileContext`, invisible to the

    /// eval surface. The closure-emit sites (which have the context) record the

    /// result here so the ctx-less eval paths — FOLD's accumulator-type probe,

    /// MAP/FILTER element typing, binding-local sizing — predict a HOF result

    /// type that AGREES with what `compile_*_to_stack` emits (which reads the

    /// real sig). Without it, eval guesses from the seed and drifts from

    /// codegen, mis-sizing a local (invalid wasm). Carried on the table because

    /// the eval recursion only ever threads `&mut SymbolTable`.

    pub(super) closure_results: HashMap<u32, crate::ast::WasmType>,

}

/// Hard ceiling on nested macro expansion. A self-reproducing macro

/// (`(defmacro m () '(m))`) would otherwise recurse until the compiler's

/// native stack overflows; this turns that into a structured compile

/// error. Each level clones the symbol table and re-enters the full

/// eval/compile recursion, so the per-level native-stack cost is high —

/// `64` (matching `MAX_STATIC_LOOP_ITERS`) stays comfortably within a

/// worker-thread stack while far exceeding any legitimate macro nesting.

pub const MAX_MACRO_EXPANSION_DEPTH: usize = 64;

/// Hard ceiling on nested eval-time function inlining. The eval path walks a

/// defun body inline for constant folding; a recursive defun whose recursion

/// doesn't fold to a base case (a runtime-arg call, or genuinely unbounded

/// recursion) would otherwise recurse the compiler's native stack until it

/// overflows. This turns that into a structured compile error.

///

/// Set conservatively below the macro ceiling: an inline level is far heavier

/// on the native stack than a macro-expansion level (it clones the table,

/// binds params, and re-enters the full `eval_value` recursion through

/// `if`/arithmetic/etc.), and compilation is not guaranteed to run on a large

/// stack — empirically a default ~2 MiB thread overflows around ~64 inline

/// levels. `32` leaves roughly a 2× native-stack margin while still allowing

/// far deeper const-folded recursion than any realistic accounting script

/// uses (the deepest legitimate cases are a handful of levels).

pub const MAX_INLINE_DEPTH: usize = 32;

impl SymbolTable {

    #[must_use]

    /// Enter one macro-expansion level, erroring once the depth ceiling is

    /// crossed. Bumped before a macro's expansion is re-evaluated (where a

    /// self-referential macro would otherwise recurse forever) and undone

    /// by [`Self::exit_macro_expansion`] once that subtree finishes, so

    /// sibling expansions don't accumulate. Turns a non-terminating macro

    /// into a structured compile error instead of a native stack overflow.

    /// Whether `name` is already being inlined further up the eval-time call

    /// chain — i.e. inlining it again would be (mutual) recursion.

    #[must_use]

    /// Mark `name` as entering an eval-time inline walk. Paired with

    /// [`Self::exit_inline`]; the depth ceiling turns a deeply-nested

    /// (or unbounded) inline recursion into a structured compile error

    /// instead of a native stack overflow — the eval-path analogue of

    /// [`Self::enter_macro_expansion`].

    /// Records the result `WasmType` for a closure signature id (see

    /// [`Self::closure_results`]). Called by the closure-emit sites, which hold

    /// the `CompileContext` and so know the sig's true result type.

    /// The recorded result `WasmType` for a closure signature id, or `None` if

    /// the closure wasn't emitted through a recording site (e.g. a closure

    /// reaching the eval surface from a path that doesn't record).

    #[must_use]

        // Re-register entity accessors after stdlib to override DEFSTRUCT-generated ones

        // Prelude loads last so its DEFUNs resolve the builtins + accessors above.

    #[must_use]

    /// Register a named test (`DEFTEST`); `RUN-TESTS` reads it via [`tests`].

    /// Re-registering an existing name overwrites its body in place (matching

    /// [`define`]'s overwrite semantics) rather than appending, so the

    /// two-surface compile — which may evaluate a `DEFTEST` on both the eval

    /// and codegen passes — stays idempotent and never double-runs a test.

        {

        }

    /// Snapshot of registered tests in declaration order. Cloned so

    /// `RUN-TESTS` can iterate without holding a borrow on the table

    /// it needs to evaluate against.

    #[must_use]

    /// Records a compile-time reference to native fn `name`. Called

    /// from the compiler's `host_fn::compile_host_fn_for_*` whenever

    /// a wasm import call is emitted for `name`.

    /// Compile-time reference counts per native fn name. The map only

    /// contains names that were emitted at least once; callers that

    /// need a complete-vs-missing report should cross-reference

    /// against the registered `HostFnSpec` list.

    #[must_use]

    /// Pre-registers the lisp-side symbol for each host fn so the compiler's

    /// resolve_arg + native-dispatch path picks them up. The symbol's value

    /// slot carries a `WasmRuntime(result-type)` stand-in so callers that

    /// eval the host-fn form during compile-time analysis (CONS element

    /// inference, arithmetic dispatch type lookup, etc.) see the right

    /// result type without needing to actually run the host fn. The

    /// matching wasm import is registered separately by

    /// `CompileContext::new_eval_with_host_fns`.

            };

            );

        }

    #[must_use]

    /// Looks up a (possibly namespaced) name via its canonical key (ADR-0029).

    /// Resolution is strict and lexical: a qualified `(Some(ns), name)` looks

    /// up only `NS:NAME`, an unqualified `(None, name)` looks up only `NAME` —

    /// there is no cross-namespace fallback and no ambient "current namespace".

    /// Most call sites pass the already-canonical `Expr::Symbol` string straight

    /// to [`Self::lookup`]; this helper is for callers that hold the split parts.

    #[must_use]

    #[must_use]

    #[must_use]

}