import "libc.hff";
import "mem.hff";
import "option.hff";

/// Types

struct Type;
struct Decl;
struct Expr;
struct Env;

struct Loc {
   fileid i16,
   col    i16,
   line   int,
   idx    isize,
}

#[lax]
enum TokT : i32 {
   // !sorted
   kw_alignof, kw_and, kw_as, kw_bitfield, kw_break, kw_case,
   kw_const, kw_continue, kw_def, kw_defer, kw_defmacro, kw_do,
   kw_else, kw_enum, kw_extern, kw_fn,
   kw_for, kw_if, kw_import, kw_let, kw_offsetof,
   kw_or, kw_return, kw_sizeof, kw_static,
   kw_struct, kw_switch, kw_typedef, kw_typeof,
   kw_union, kw_while,
   NUM_KEYWORDS,
   int = -100,
   flo,
   bool,
   str,
   chr,
   null,
   ident,
   macident,
   gensym,
   label,
   strify,
   typearg,
   eof,
}
def NUM_KEYWORDS = as(int)TokT:NUM_KEYWORDS;

struct Tok {
   t TokT,
   loc Loc,
   ty *const Type,
   u union {
      int i64,
      uint u64,
      flo f64,
      bool bool,
      str [#]const u8,
      ident *const u8,
   },
}

enum AggKind {
   Struct,
   Union,
   EUnion,
}

struct AggField {
   name *const u8,
   ty *const Type,
   off usize,
}

struct EnumVal { name *const u8, i i64 }

struct BitFField {
   name *const u8,
   ty *const Type,
   off u16, size u16
}

enum union TeplArg;

struct Type {
   size  usize,
   align usize,
   konst bool,
   id    uint,
   u enum union {
      Void,
      Bool,
      Int struct { sgn bool },
      Flo,
      Ptr *const Type,
      Arr struct { child *const Type, length i64 },
      Slice *const Type,
      Fn struct {
         params [#]*const Type,
         variadic bool,
         ret *const Type,
      },
      Enum struct {
         intty *const Type,
         name *const u8,
         lax bool,
         id int,
         vals [#]EnumVal,
      },
      Agg struct {
         kind AggKind,
         name *const u8,
         id int,
         fwd bool,
         enumty *const Type,
         tpargs [#]TeplArg,
         flds [#]AggField,
         decls *Env,
      },
      BitF struct {
         intty *const Type,
         name *const u8,
         id int,
         flds [#]BitFField,
      },
      VaList,
   },

   fn is(ty *const Type, tag typeof((Type{}).u.#tag)) bool {
      return ty.u.#tag == tag;
   }
}

struct Fn;
struct Expan;
struct Block;
struct Parser {
   fp *FILE,
   alloc *Allocator,
   tlalloc *Allocator,
   curfile *const u8,
   curfn *Fn,
   curenv *Env,
   curloop int,
   curblock *Block,
   curexpan *Expan,
   expanno int,
   loopid int,
   varid int,
   targty *const Type,
   tokloc Loc,
   curloc Loc,
   eof bool,
   error bool,
   is_header bool,
   peekchr Option<int>,
   peektok Option<Tok>,
}

enum UnOp {
   neg,
   not,
   compl,
   deref,
   addrof,
   postinc,
   preinc,
   postdec,
   predec,
}

struct Stmt;
struct Defers;
struct Block {
   sts [#]Stmt,
   defers *Defers,
   id int,
}

struct Expr {
   loc Loc,
   ty *const Type,
   u enum union {
      IntLit union { i i64, u u64 },
      FloLit f64,
      StrLit [#]const u8,
      BoolLit bool,
      NullLit,
      Symbol *Decl,
      BinOp struct { op TokT, lhs *Expr, rhs *Expr },
      UnOp struct { op UnOp, ex *Expr },
      Cond struct { test *Expr, t *Expr, f *Expr },
      Cast *Expr,
      Dot struct { lhs *Expr, fld *const AggField },
      BitDot struct { lhs *Expr, fld *const BitFField },
      SLen *Expr,
      SPtr *Expr,
      EUTag *Expr,
      BitRaw *Expr,
      Index struct { lhs *Expr, rhs *Expr },
      Slice struct { lhs *Expr, begin *Expr, end *Expr },
      Call struct { lhs *Expr, args [#]Expr },
      ZeroIni,
      EnumIni i64,
      EUnionIni struct { var *const AggField, ex *Expr },
      AggIni struct { flds [#]*const AggField, exs [#]Expr },
      ArrIni struct { idxs [#]u32, exs [#]Expr, maxn i64 },
      VaStart *Expr,
      VaArg *Expr,
      VaCopy struct { dst *Expr, src *Expr },
      VaEnd *Expr,
      Stmt Block,
   }
}

struct Defers {
   next *Defers,
   blockid int,
   age int,
   ex Expr
}

struct ISwitchCase {
   es [#]Expr,
   t Block
}

struct EUSwitchCase {
   capt *const u8,
   captptr bool,
   captid int,
   variant int,
   captty *const Type,
   fld *AggField,
   t Block
}

struct CSwitchCase {
   test Expr,
   t Block,
}

struct Stmt {
   loc Loc,
   u enum union {
      Block Block,
      If struct { test Expr, t Block, f Block },
      While struct { test Expr, body Block, id int },
      DoWhile struct { test Expr, body Block, id int },
      For struct {
         ini Block,
         test Expr,
         next Option<Expr>,
         body Block,
         id int,
      },
      Break #{loopid} int,
      Continue #{loopid} int,
      Return struct { ex Option<Expr>, deferage int },
      Expr Expr,
      Decl *Decl,
      ISwitch struct { ex Expr, cs [#]ISwitchCase, f Block },
      EUSwitch struct { lvalue bool, ex Expr, cs [#]EUSwitchCase, f Block },
      CSwitch struct { cs [#]CSwitchCase, f Block }
   }
}

struct Fn {
   ty *const Type,
   paramnames [#]*const u8,
   variadic bool,
   id int,
   body Option<Block>
}

struct Var {
   ty *const Type,
   ini Option<Expr>,
   fwd bool,
   fnid int,
   id int,
}

struct MacroCase {
   variadic bool,
   bodyarg bool,
   params [#]*const u8,
   body [#]Tok,
}

struct Macro {
   cs [#]MacroCase
}

struct TeplParam {
   name *const u8,
   u enum union {
      Ty,
      Val *const Type,
   }
}

enum union TeplArg {
   Ty *const Type,
   Val Tok,
}

struct TeplCache {
   next *TeplCache,
   args [#]TeplArg,
   ty *const Type,
}

struct Tepl {
   kind AggKind,
   env *Env,
   params [#]TeplParam,
   toks [#]Tok,
   cache *TeplCache,
}

struct Decl {
   name *const u8,
   loc Loc,
   externp bool,
   toplevel bool,
   u enum union {
      Let Var,
      Static Var,
      Ty *const Type,
      Def Expr,
      Fn Fn,
      Macro Macro,
      Tepl Tepl,
      Label #{loopid} int,
   },
   myenv *Env,
}

fn islvalue(ex *Expr) bool {
   switch ex.u {
   case Symbol decl;
      return decl.u.#tag == :Let or decl.u.#tag == :Static;
   case UnOp u;
      return u.op == :deref;
   case Index idx;
      return idx.lhs.ty->is(:Ptr) or islvalue(idx.lhs);
   case Dot dot;
      return dot.lhs.ty->is(:Ptr) or islvalue(dot.lhs);
   case BitDot bdot;
      return bdot.lhs.ty->is(:Ptr) or islvalue(bdot.lhs);
   case BitRaw ex;
      return ex.ty->is(:Ptr) or islvalue(ex);
   case EUTag;
      return #t;
   }
   return #f;
}

def ATTR_LAX = 1u32;

struct ExpanArg {
   name *const u8,
   toks [#]Tok,
}
struct Expan {
   prev *Expan,
   args [#]ExpanArg,
   toks [#]Tok,
   name *const u8,
   loc Loc,
   tepl bool,
   peektok Option<Tok>,
   idx int,
}

struct DeclList {
   link *DeclList,
   decl Decl,
}

struct Targ {
   name *const u8,
   ptrsize    u8,
   intsize    u8,
   i64align   u8,
   longsize   u8, longalign  u8,
   llongsize  u8, llongalign u8,
   sizesize   u8,
   f64align   u8,
   valistsize u8, valistalign u8,
   valistllvmty *const u8,
   charsigned bool,
   shortenum  bool,

   triple *const u8,
}

// parse.cff
extern static keyword2str [NUM_KEYWORDS]*const u8;
extern fn parser_init(*Parser, path *const u8) void;
extern fn parse(*Parser) [#]Decl;

// fmt.cff
extern fn vpfmt(proc *fn(u8, *void) void, parg *void, fmt *const u8, va_list) void;
extern fn pfmt(proc *fn(u8, *void) void, parg *void, fmt *const u8, ...) void;
extern fn vefmt(fmt *const u8, ap va_list) void;
extern fn efmt(fmt *const u8, ...) void;
extern fn ssfmt(fmt *const u8, ...) *const u8;
extern fn warn(P *Parser, Loc, fmt *const u8, ...) void;
extern fn err(P *Parser, Loc, fmt *const u8, ...) void;
extern fn fatal(*Parser, Loc, fmt *const u8, ...) void;

// targ.cff
extern static g_targ Targ;
extern static host_target_triple const *const u8;
extern fn targ_ini(name *const u8) bool;
extern fn triple2targ(triple *const u8) *const u8;

// type.cff
extern static ty_void     *const Type,
              ty_bool     *const Type,
              ty_i8       *const Type,
              ty_u8       *const Type,
              ty_i16      *const Type,
              ty_u16      *const Type,
              ty_i32      *const Type,
              ty_u32      *const Type,
              ty_int      *const Type,
              ty_uint     *const Type,
              ty_i64      *const Type,
              ty_u64      *const Type,
              ty_isize    *const Type,
              ty_usize    *const Type,
              ty_iptrint  *const Type,
              ty_uptrint  *const Type,
              ty_f32      *const Type,
              ty_f64      *const Type,
              ty_voidptr  *const Type,
              ty_c_char   *const Type,
              ty_c_long   *const Type,
              ty_c_ulong  *const Type,
              ty_c_llong  *const Type,
              ty_c_ullong *const Type,
              ty_c_valist *const Type;
extern fn interntype(Type) *const Type;
extern fn putprimtypes(env *Env) void;
fn constify(ty *const Type) *const Type {
   if ty.konst or ty.u.#tag == :Fn {
      return ty;
   }
   let ty2 = *ty;
   ty2.konst = #t;
   return interntype(ty2);
}
fn unconstify(ty *const Type) *const Type {
   if !ty.konst {
      return ty;
   }
   let ty2 = *ty;
   ty2.konst = #f;
   return interntype(ty2);
}
fn mkarrtype(len i64, konst bool, child *const Type) *const Type {
   return interntype({
      len * child.size,
      child.align,
      .u: :Arr { konst ? constify(child) : child, len }
   });
}
fn mkptrtype(child *const Type) *const Type {
   return interntype({
      g_targ.ptrsize,
      .u: :Ptr(child)
   });
}
extern fn mkslicetype(child *const Type) *const Type;

fn childtype(ty *const Type) *const Type {
   switch ty.u {
   case Ptr t; return t;
   case Arr a; return a.child;
   case Slice t; return t;
   }
   return #null;
}
extern fn completetype(ty *const Type) bool;
fn isnumtype(ty *const Type) bool {
   return ty->is(:Int) or ty->is(:Flo) or (ty->is(:Enum) and ty.u.Enum.lax);
}
extern fn typeof2(a *const Type, b *const Type) *const Type;
extern fn visittypes(*fn(*const Type, *void) void, *void) void;

// env.cff
extern fn mkenv(parent *Env, alloc *Allocator) *Env;
extern fn envparent(*Env) *Env;
extern fn envput(*Env, Decl, **const Decl) *Decl;
extern fn envput_alloc(*Env, *Allocator, Decl, **const Decl) *Decl;
extern fn envfind(*Env, *const u8) *Decl;
extern fn envfind_noparent(*Env, *const u8) *Decl;
extern fn envfree(*Env) void;

// fold.cff
extern fn fold(*Expr) bool;

// llvm.cff
extern fn llvm_addtype(*const Type) void;
extern fn llvm_addglobl(*Decl, staticp bool) void;
extern fn llvm_genfn(externp bool, name *const u8, f *Fn) void;
extern fn llvm_genstatic(externp bool, name *const u8, var *Var) void;
extern fn llvm_init(*FILE) void;
extern fn llvm_fini() void;