#include"parse.h"

#include"vm.h"
#include<alloca.h>

#define i_key LInst
#include"stc/vec.h"

#define i_key int32_t
#include"stc/vec.h"

#define i_key LFunc
#include"stc/vec.h"

typedef struct ScopeItem {
	Token name;
	int vreg;
	
	struct ScopeItem *next;
} ScopeItem;

typedef struct Scope {
	struct Scope *parent;
	ScopeItem *items;
} Scope;

ScopeItem *scope_get(Scope *scope, const char *name) {
	for(ScopeItem *si = scope->items; si; si = si->next) {
		if(!strcmp(si->name.text, name)) {
			return si;
		}
	}
	return NULL;
}
	
ScopeItem *scope_find(Scope *scope, const char *name) {
	while(scope) {
		ScopeItem *si = scope_get(scope, name);
		if(si) {
			return si;
		}
		scope = scope->parent;
	}
	return NULL;
}
	
void scope_set_direct(Scope *scope, ScopeItem *new) {
	new->next = scope->items;
	scope->items = new;
}

typedef struct {
	vec_LInst instrs;
	int used_vregs[256];
} Chunk;

typedef struct {
	size_t i;
	size_t sz;
	Token *tokens;
	
	LTable *environment;
	
	Scope *scope;
	
	vec_LFunc unit_functions;
	
	size_t abyss_size;
	uint8_t *abyss;
	
	Chunk current_chunk;
} Parser;

typedef enum ExprKind {
	EX_LOCAL,
	EX_GLOBAL,
	EX_INT,
	EX_FLOAT,
	EX_BOOL,
	EX_ADD,
	EX_SUB,
	EX_MUL,
	EX_DIV,
	EX_IDIV,
	EX_MOD,
	EX_POW,
	EX_BAND,
	EX_BOR,
	EX_BXOR,
	EX_AND,
	EX_OR,
	EX_EQ,
	EX_NEQ,
	EX_TBL_LIT,
	EX_FUNC_LIT,
	EX_DOT,
	EX_INDEX,
	EX_CALL,
	EX_STR,
	EX_LENGTH,
} ExprKind;
typedef struct Expr {
	ExprKind kind;
	struct Expr *next_to_die;
	union {
		struct {
			struct Expr *A;
			union {
				struct Expr *B;
				Token B_tok;
			};
		};
		Token name;
		intmax_t i;
		double f;
		bool b;
		struct {
			uint8_t sub_count;
			struct Expr *subs[];
		};
		struct {
			size_t table_first_token;
			size_t table_last_token;
		};
	};
} Expr;

size_t abyss_insert(Parser *P, uint8_t *data, size_t len) {
	size_t idx = P->abyss_size;
	
	P->abyss = realloc(P->abyss, P->abyss_size += len);
	
	if(data) {
		memcpy(P->abyss + idx, data, len);
	}
	
	return idx;
}

Token peek(Parser *P, int offset) {
	if(P->i + offset >= P->sz) {
		Token t = P->tokens[P->sz - 1];
		t.type = TOK_EOF;
		return t;
	}
	return P->tokens[P->i + offset];
}

Token get(Parser *P) {
	Token t = peek(P, 0);
	P->i++;
	return t;
}

Token expect(Parser *P, TokenType type) {
	Token t = get(P);
	assert(t.type == type);
	return t;
}

bool maybe(Parser *P, TokenType type) {
	if(peek(P, 0).type == type) {
		P->i++;
		return true;
	} else {
		return false;
	}
}

int find_vreg(Parser *P) {
	for(int i = 255; i >= 0; i--) {
		if(!P->current_chunk.used_vregs[i]) {
			return i;
		}
	}
	assert(false);
}

void alloc_vreg(Parser *P, int vreg) {
	P->current_chunk.used_vregs[vreg]++;
}

void free_vreg(Parser *P, int vreg) {
	P->current_chunk.used_vregs[vreg]--;
	assert(P->current_chunk.used_vregs[vreg] >= 0 && "Cannot free unused vreg");
}

static void scope_kill(Parser *P) {
	Scope *parent = P->scope->parent;
	
	for(ScopeItem *si = P->scope->items; si;) {
		ScopeItem *next = si->next;
		free(si);
		si = next;
	}
	free(P->scope);
	
	P->scope = parent;
}

void parse_chunk(Parser *P);

int parse_functiondef(Parser *P, bool can_be_local) {
	size_t old_idx = P->i;
	
	if(!(peek(P, 0).type == TOK_FUNCTION || (can_be_local && peek(P, 0).type == TOK_LOCAL && peek(P, 1).type == TOK_FUNCTION))) {
		goto err;
	}
	
	bool is_local = maybe(P, TOK_LOCAL);
	
	expect(P, TOK_FUNCTION);
	
	Token name = {};
	if(peek(P, 0).type == TOK_NAME) {
		name = get(P);
	}
	
	if(!maybe(P, TOK_PAREN_L)) {
		goto err;
	}
	
	Chunk old_chunk = P->current_chunk;
	P->current_chunk = (Chunk) {};
	
	Scope *new_scope = calloc(1, sizeof(*new_scope));
	new_scope->parent = P->scope;
	P->scope = new_scope;
	
	size_t arg_count = 0;
	if(!maybe(P, TOK_PAREN_R)) {
		while(1) {
			if(peek(P, 0).type != TOK_NAME) {
				goto err;
			}
			
			ScopeItem *si = calloc(1, sizeof(*si));
			si->name = expect(P, TOK_NAME);
			si->vreg = arg_count++;
			scope_set_direct(P->scope, si);
			
			if(maybe(P, TOK_PAREN_R)) {
				break;
			} else {
				if(peek(P, 0).type != TOK_COMMA) {
					goto err;
				}
			}
		}
	}
	
	parse_chunk(P);
	if(P->current_chunk.instrs.data[P->current_chunk.instrs.size - 1].opcode != L_RET) {
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_RET, .argb = {0}});
	}
	
	expect(P, TOK_END);
	
	assert(P->unit_functions.size > 0);
	
	LFunc lf = {};
	lf.unit = P->unit_functions.data[0].unit;
	lf.is_native = false;
	lf.lua_instrs = P->current_chunk.instrs.data;
	lf.env = P->environment;
	vec_LFunc_push(&P->unit_functions, lf);
	
	size_t function_idx = P->unit_functions.size - 1;
	
	P->current_chunk = old_chunk;
	scope_kill(P);
	
	int vreg = find_vreg(P);
	assert(vreg != -1);
	
	vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETFUNC, .a = vreg, .bc = function_idx});
	
	if(name.text) {
		if(is_local) {
			alloc_vreg(P, vreg);
			
			ScopeItem *si = calloc(1, sizeof(*si));
			si->name = name;
			si->vreg = vreg;
			
			scope_set_direct(P->scope, si);
		} else {
			size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(name.text));
			*(uint16_t*) &P->abyss[abyss_idx] = strlen(name.text);
			memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], name.text, strlen(name.text));
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETGLOBAL, .a = vreg, .bc = abyss_idx});
		}
	}
	
	return vreg;
err:
	P->i = old_idx;
	return -1;
}

Expr *desc_exp(Parser *P);
Expr *desc_subexp(Parser *P, int priority);
void emit_expr(Parser *P, int assigned_vreg, Expr *expr);

bool parse_functioncall(Parser *P) {
	size_t old_idx = P->i;
	
	Expr *ex = desc_exp(P);
	
	if(ex->kind != EX_CALL) {
		goto err;
	}
	
	emit_expr(P, find_vreg(P), ex);
	
	return true;
err:
	P->i = old_idx;
	return false;
}

vec_Token parse_namelist(Parser *P) {
	vec_Token v = {};
	
	vec_Token_push(&v, expect(P, TOK_NAME));
	
	while(maybe(P, TOK_COMMA)) {
		vec_Token_push(&v, expect(P, TOK_NAME));
	}
	
	return v;
}

static Expr *last_desc = NULL;
static Expr *mark_for_death(Expr *e) {
	e->next_to_die = last_desc;
	last_desc = e;
	return e;
}
static Expr *new_expr(size_t space) {
	Expr *e = calloc(1, sizeof(*e) + space);
	mark_for_death(e);
	return e;
}
Expr *desc_subexp(Parser *P, int priority) {
	if(priority == 0) {
		Expr *a = desc_subexp(P, priority + 1);
		
		while(maybe(P, TOK_DOUBLE_EQUAL) || maybe(P, TOK_NOT_EQUAL)) {
			Token op = peek(P, -1);
			
			Expr *b = desc_subexp(P, priority + 1);
			
			Expr *opex = new_expr(0);
			opex->A = a;
			opex->B = b;
			
			if(op.type == TOK_DOUBLE_EQUAL) {
				opex->kind = EX_EQ;
			} else if(op.type == TOK_NOT_EQUAL) {
				opex->kind = EX_NEQ;
			}
			
			a = opex;
		}
		
		return a;
	} else if(priority == 1) {
		Expr *a = desc_subexp(P, priority + 1);
		
		while(peek(P, 0).type == TOK_PLUS || peek(P, 0).type == TOK_MINUS) {
			Token op = get(P);
			
			Expr *b = desc_subexp(P, priority + 1);
			
			Expr *opex = new_expr(0);
			opex->A = a;
			opex->B = b;
			
			if(op.type == TOK_PLUS) {
				opex->kind = EX_ADD;
			} else {
				opex->kind = EX_SUB;
			}
			
			a = opex;
		}
		
		return a;
	} else if(priority == 2) {
		Expr *a = desc_subexp(P, priority + 1);
		
		while(peek(P, 0).type == TOK_MUL || peek(P, 0).type == TOK_DIV || peek(P, 0).type == TOK_IDIV || peek(P, 0).type == TOK_PERCENT) {
			Token op = get(P);
			
			Expr *b = desc_subexp(P, priority + 1);
			
			Expr *opex = new_expr(0);
			opex->A = a;
			opex->B = b;
			
			if(op.type == TOK_MUL) {
				opex->kind = EX_MUL;
			} else if(op.type == TOK_DIV) {
				opex->kind = EX_DIV;
			} else if(op.type == TOK_IDIV) {
				opex->kind = EX_IDIV;
			} else if(op.type == TOK_PERCENT) {
				opex->kind = EX_MOD;
			}
			
			a = opex;
		}
		
		return a;
	} else if(priority == 3) {
		Expr *e = NULL;
		
		if(maybe(P, TOK_SHARP)) {
			e = new_expr(0);
			e->kind = EX_LENGTH;
			e->A = desc_subexp(P, priority);
		} else if(maybe(P, TOK_TRUE)) {
			e = new_expr(0);
			e->kind = EX_BOOL;
			e->b = true;
		} else if(maybe(P, TOK_FALSE)) {
			e = new_expr(0);
			e->kind = EX_BOOL;
			e->b = false;
		} else if(maybe(P, TOK_NUMBER)) {
			P->i--;
			
			Token num = expect(P, TOK_NUMBER);
			long i = strtol(num.text, NULL, 10);
			
			e = new_expr(0);
			e->kind = EX_INT;
			e->i = i;
		} else if(maybe(P, TOK_NAME)) {
			P->i--;
			
			Token name = expect(P, TOK_NAME);
			
			ScopeItem *si = scope_find(P->scope, name.text);
			
			e = new_expr(0);
			e->kind = si ? EX_LOCAL : EX_GLOBAL;
			e->name = name;
		} else if(maybe(P, TOK_STRING)) {
			P->i--;
			
			Token str = expect(P, TOK_STRING);
			
			e = new_expr(0);
			e->kind = EX_STR;
			e->name = str;
		} else if(maybe(P, TOK_FUNCTION)) {
			e = new_expr(0);
			e->kind = EX_FUNC_LIT;
			e->table_first_token = P->i - 1;
			
			size_t depth = 1;
			while(1) {
				Token t = get(P);
				if(t.type == TOK_THEN || t.type == TOK_DO) {
					depth++;
				} else if(t.type == TOK_END) {
					depth--;
					if(depth == 0) {
						break;
					}
				}
			}
			
			e->table_last_token = P->i - 1;
		} else if(maybe(P, TOK_SQUIGGLY_L)) {
			e = new_expr(0);
			e->kind = EX_TBL_LIT;
			e->table_first_token = P->i - 1;
			
			size_t depth = 1;
			while(1) {
				Token t = get(P);
				if(t.type == TOK_SQUIGGLY_L) {
					depth++;
				} else if(t.type == TOK_SQUIGGLY_R) {
					depth--;
					if(depth == 0) {
						break;
					}
				}
			}
			
			e->table_last_token = P->i - 1;
		}
		
		if(e) {
			while(maybe(P, TOK_PAREN_L) || maybe(P, TOK_DOT) || maybe(P, TOK_SQUAREN_L)) {
				if(peek(P, -1).type == TOK_PAREN_L) {
					Expr *call = new_expr(sizeof(Expr*) + sizeof(Expr*) * 32);
					call->kind = EX_CALL;
					call->sub_count = 1;
					call->subs[0] = e;
					
					if(!maybe(P, TOK_PAREN_R)) {
						while(1) {
							call->subs[call->sub_count++] = desc_exp(P);
							
							if(maybe(P, TOK_PAREN_R)) {
								break;
							} else {
								expect(P, TOK_COMMA);
							}
						}
					}
					
					e = call;
				} else if(peek(P, -1).type == TOK_DOT) {
					Expr *dot = new_expr(0);
					dot->kind = EX_DOT;
					dot->A = e;
					dot->B_tok = expect(P, TOK_NAME);

					e = dot;
				} else if(peek(P, -1).type == TOK_SQUAREN_L) {
					Expr *index = new_expr(0);
					index->kind = EX_INDEX;
					index->A = e;
					index->B = desc_exp(P);
					
					expect(P, TOK_SQUAREN_R);
					
					e = index;
				}
			}
			
			return e;
		}
	}
	return NULL;
}

Expr *desc_exp(Parser *P) {
	return desc_subexp(P, 0);
}

/*void parse_exp_priority(Parser *P, int assigned_vreg, int priority) {
	if(priority == 0) {
		parse_exp_priority(P, assigned_vreg, priority + 1);
		
		while(peek(P, 0).type == TOK_DOUBLE_EQUAL) {
			int vreg = find_vreg(P);
			
			Token op = get(P);
			
			alloc_vreg(P, vreg);
			parse_exp_priority(P, vreg, priority + 1);
			free_vreg(P, vreg);
			
			if(op.type == TOK_DOUBLE_EQUAL) {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_COND_EQ, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			}
		}
	} else if(priority == 1) {
		parse_exp_priority(P, assigned_vreg, priority + 1);
		
		while(peek(P, 0).type == TOK_MUL || peek(P, 0).type == TOK_DIV || peek(P, 0).type == TOK_PERCENT || peek(P, 0).type == TOK_IDIV) {
			int vreg = find_vreg(P);
			
			Token op = get(P);
			
			alloc_vreg(P, vreg);
			parse_exp_priority(P, vreg, priority + 1);
			free_vreg(P, vreg);
			
			if(op.type == TOK_MUL) {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_MUL, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			} else if(op.type == TOK_DIV) {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_DIV, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			} else if(op.type == TOK_PERCENT) {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_MOD, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			} else {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_IDIV, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			}
		}
	} else if(priority == 2) {
		parse_exp_priority(P, assigned_vreg, priority + 1);
		
		while(peek(P, 0).type == TOK_PLUS || peek(P, 0).type == TOK_MINUS) {
			int vreg = find_vreg(P);
			
			Token op = get(P);
			
			alloc_vreg(P, vreg);
			parse_exp_priority(P, vreg, priority + 1);
			free_vreg(P, vreg);
			
			if(op.type == TOK_PLUS) {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_ADD, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			} else {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SUB, .a = assigned_vreg, .b = assigned_vreg, .c = vreg});
			}
		}
	} else if(priority == 3) {
		if(maybe(P, TOK_TRUE)) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETBOOL, .a = assigned_vreg, .b = true});
		} else if(maybe(P, TOK_FALSE)) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETBOOL, .a = assigned_vreg, .b = false});
		} else if(maybe(P, TOK_NIL)) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETNIL, .a = assigned_vreg});
		} else if(maybe(P, TOK_SQUIGGLY_L)) {
			expect(P, TOK_SQUIGGLY_R);
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETTABLE, .a = assigned_vreg, .bc = 8});
		} else if(peek(P, 0).type == TOK_NAME) {
			Token name = expect(P, TOK_NAME);
			
			ScopeItem *si = scope_find(P->scope, name.text);
			
			if(!si) {
				size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(name.text));
				*(uint16_t*) &P->abyss[abyss_idx] = strlen(name.text);
				memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], name.text, strlen(name.text));
				
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_GETGLOBAL, .a = assigned_vreg, .b = abyss_idx});
			} else {
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_MOVE, .a = assigned_vreg, .b = si->vreg});
			}
		} else if(peek(P, 0).type == TOK_NUMBER) {
			Token num = expect(P, TOK_NUMBER);
			
			long i = strtol(num.text, NULL, 10);
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETINT16, .a = assigned_vreg, .bc = i});
		} else if(peek(P, 0).type == TOK_STRING) {
			Token str = expect(P, TOK_STRING);
			
			size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(str.text));
			*(uint16_t*) &P->abyss[abyss_idx] = strlen(str.text);
			memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], str.text, strlen(str.text));
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETSTR, .a = assigned_vreg, .bc = abyss_idx});
		} else {
			assert(false);
		}
	}
}*/

void emit_expr(Parser *P, int assigned_vreg, Expr *expr) {
	if(expr->kind == EX_LOCAL) {
		ScopeItem *si = scope_find(P->scope, expr->name.text);
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_MOVE, .a = assigned_vreg, .b = si->vreg});
	} else if(expr->kind == EX_GLOBAL) {
		size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(expr->name.text));
		*(uint16_t*) &P->abyss[abyss_idx] = strlen(expr->name.text);
		memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], expr->name.text, strlen(expr->name.text));
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_GETGLOBAL, .a = assigned_vreg, .b = abyss_idx});
	} else if(expr->kind == EX_INT) {
		if(expr->i <= 32767 && expr->i >= -32768) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETINT16, .a = assigned_vreg, .bc = expr->i});
		} else {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETINT32, .a = assigned_vreg, .bc = abyss_insert(P, (uint8_t*) &expr->i, 4)});
		}
	} else if(expr->kind == EX_FLOAT) {
		assert(false);
	} else if(expr->kind == EX_BOOL) {
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETBOOL, .a = assigned_vreg, .bc = expr->b});
	} else if(expr->kind == EX_STR) {
		size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(expr->name.text));
		*(uint16_t*) &P->abyss[abyss_idx] = strlen(expr->name.text);
		memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], expr->name.text, strlen(expr->name.text));
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETSTR, .a = assigned_vreg, .bc = abyss_idx});
	} else if(expr->kind == EX_CALL) {
		int vreg = find_vreg(P);
		assert(vreg != -1);
		
		emit_expr(P, vreg, expr->subs[0]);
		alloc_vreg(P, vreg);
		
		uint8_t buf[258] = {};
		
		uint8_t *ret_vreg = buf + 0;
		uint8_t *arg_count = buf + 1;
		uint8_t *args = buf + 2;
		
		for(size_t i = 1; i < expr->sub_count; i++) {
			int av = find_vreg(P);
			emit_expr(P, av, expr->subs[i]);
			args[(*arg_count)++] = av;
			alloc_vreg(P, av);
		}
		
		*ret_vreg = find_vreg(P);
		
		free_vreg(P, vreg);
		for(int i = 0; i < *arg_count; i++) {
			free_vreg(P, args[i]);
		}
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_CALL, .a = vreg, .bc = abyss_insert(P, buf, 2 + *arg_count)});
	} else if(expr->kind == EX_FUNC_LIT) {
		size_t old_idx = P->i;
		
		P->i = expr->table_first_token;
		
		expect(P, TOK_FUNCTION);
		
		expect(P, TOK_PAREN_L);
		
		Chunk old_chunk = P->current_chunk;
		P->current_chunk = (Chunk) {};
		
		Scope *new_scope = calloc(1, sizeof(*new_scope));
		new_scope->parent = P->scope;
		P->scope = new_scope;
		
		size_t arg_count = 0;
		if(!maybe(P, TOK_PAREN_R)) {
			while(1) {
				expect(P, TOK_NAME);
				
				P->i--;
				
				ScopeItem *si = calloc(1, sizeof(*si));
				si->name = expect(P, TOK_NAME);
				si->vreg = arg_count++;
				scope_set_direct(P->scope, si);
				
				if(maybe(P, TOK_PAREN_R)) {
					break;
				} else {
					expect(P, TOK_COMMA);
				}
			}
		}
		
		parse_chunk(P);
		if(P->current_chunk.instrs.data[P->current_chunk.instrs.size - 1].opcode != L_RET) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_RET, .argb = {0}});
		}
		
		expect(P, TOK_END);
		
		assert(P->unit_functions.size > 0);
		
		LFunc lf = {};
		lf.unit = P->unit_functions.data[0].unit;
		lf.is_native = false;
		lf.lua_instrs = P->current_chunk.instrs.data;
		lf.env = P->environment;
		vec_LFunc_push(&P->unit_functions, lf);
		
		size_t function_idx = P->unit_functions.size - 1;
		
		P->current_chunk = old_chunk;
		scope_kill(P);
		
		P->i = old_idx;
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETFUNC, .a = assigned_vreg, .bc = function_idx});
	} else if(expr->kind == EX_TBL_LIT) {
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETTABLE, .a = assigned_vreg, .bc = 16});

		size_t old_idx = P->i;
		P->i = expr->table_first_token;

		expect(P, TOK_SQUIGGLY_L);
		
		alloc_vreg(P, assigned_vreg);

		if(!maybe(P, TOK_SQUIGGLY_R)) {
			while(1) {
				int keyv = find_vreg(P);
				assert(keyv != -1);
				if(peek(P, 0).type == TOK_NAME) {
					Token name = get(P);
					
					size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(name.text));
					*(uint16_t*) &P->abyss[abyss_idx] = strlen(name.text);
					memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], name.text, strlen(name.text));
					
					vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETSTR, .a = keyv, .bc = abyss_idx});
				} else {
					expect(P, TOK_SQUAREN_L);
					emit_expr(P, keyv, desc_exp(P));
					expect(P, TOK_SQUAREN_R);
				}

				expect(P, TOK_EQUAL);

				alloc_vreg(P, keyv);
				int valv = find_vreg(P);
				emit_expr(P, valv, desc_exp(P));
				free_vreg(P, keyv);

				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETFIELD, .a = assigned_vreg, .b = keyv, .c = valv});

				if(maybe(P, TOK_SQUIGGLY_R)) {
					break;
				} else {
					expect(P, TOK_COMMA);
				}
			}
		}
		
		free_vreg(P, assigned_vreg);

		P->i = old_idx;
	} else if(expr->kind == EX_DOT) {
		Token field = expr->B_tok;

		emit_expr(P, assigned_vreg, expr->A);
		alloc_vreg(P, assigned_vreg);
		
		size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(field.text));
		*(uint16_t*) &P->abyss[abyss_idx] = strlen(field.text);
		memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], field.text, strlen(field.text));

		int keyv = find_vreg(P);
		assert(keyv != -1);
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETSTR, .a = keyv, .bc = abyss_idx});
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_GETFIELD, .a = assigned_vreg, .b = assigned_vreg, .c = keyv});
		
		free_vreg(P, assigned_vreg);
	} else if(expr->kind == EX_INDEX) {
		emit_expr(P, assigned_vreg, expr->A);
		
		alloc_vreg(P, assigned_vreg);
		int keyv = find_vreg(P);
		emit_expr(P, keyv, expr->B);
		free_vreg(P, assigned_vreg);
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_GETFIELD, .a = assigned_vreg, .b = assigned_vreg, .c = keyv});
	} else if(expr->kind == EX_LENGTH) {
		emit_expr(P, assigned_vreg, expr->A);
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_LEN, .a = assigned_vreg, .b = assigned_vreg, .c = 0});
	} else {
		assert(expr->kind == EX_ADD || expr->kind == EX_SUB || expr->kind == EX_MUL || expr->kind == EX_DIV || expr->kind == EX_IDIV || expr->kind == EX_MOD || expr->kind == EX_POW || expr->kind == EX_BAND || expr->kind == EX_BOR || expr->kind == EX_BXOR || expr->kind == EX_AND || expr->kind == EX_OR || expr->kind == EX_EQ || expr->kind == EX_NEQ);
		
		assert(expr->A);
		assert(expr->B);
		
		emit_expr(P, assigned_vreg, expr->A);

		alloc_vreg(P, assigned_vreg);
		int b_vreg = find_vreg(P);
		emit_expr(P, b_vreg, expr->B);
		free_vreg(P, assigned_vreg);
		
		uint8_t opcode;
		switch(expr->kind) {
		case EX_ADD: opcode = L_ADD; break;
		case EX_SUB: opcode = L_SUB; break;
		case EX_MUL: opcode = L_MUL; break;
		case EX_DIV: opcode = L_DIV; break;
		case EX_IDIV: opcode = L_IDIV; break;
		case EX_MOD: opcode = L_MOD; break;
		case EX_POW: opcode = L_POW; break;
		case EX_EQ: opcode = L_COND_EQ; break;
		case EX_NEQ: opcode = L_COND_NEQ; break;
		default: assert(false);
		}
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = opcode, .a = assigned_vreg, .b = assigned_vreg, .c = b_vreg});
	}
}

int parse_exp(Parser *P, int assigned_vreg) {
	bool owned = false;
	if(assigned_vreg == -1) {
		owned = true;
		
		assigned_vreg = find_vreg(P);
		alloc_vreg(P, assigned_vreg);
	}
	
	emit_expr(P, assigned_vreg, desc_exp(P));
	
	if(owned) {
		free_vreg(P, assigned_vreg);
	}
	
	return assigned_vreg;
}

bool parse_assignment(Parser *P) {
	size_t old_idx = P->i;
	
	const size_t max_exprs = 8;
	
	Expr *lhs[max_exprs];
	size_t lhsi = 0;
	
	Expr *rhs[max_exprs];
	int rhsv[max_exprs];
	size_t rhsi = 0;
	
	while(1) {
		lhs[lhsi++] = desc_exp(P);
		
		if(!lhs[lhsi - 1]) {
			goto err;
		}
		
		if(lhs[lhsi - 1]->kind != EX_LOCAL && lhs[lhsi - 1]->kind != EX_GLOBAL && lhs[lhsi - 1]->kind != EX_DOT && lhs[lhsi - 1]->kind != EX_INDEX) {
			goto err;
		}
		
		if(maybe(P, TOK_EQUAL)) {
			break;
		} else {
			expect(P, TOK_COMMA);
		}
	}
	
	rhs[rhsi++] = desc_exp(P);
	
	while(1) {
		if(!maybe(P, TOK_COMMA)) {
			break;
		}
		
		rhs[rhsi++] = desc_exp(P);
	}
	
	for(size_t i = 0; i < rhsi; i++) {
		rhsv[i] = find_vreg(P);
		emit_expr(P, rhsv[i], rhs[i]);
		alloc_vreg(P, rhsv[i]);
	}
	
	assert(rhsi == lhsi);
	
	for(size_t i = 0; i < lhsi; i++) {
		if(lhs[i]->kind == EX_LOCAL) {
			ScopeItem *si = scope_find(P->scope, lhs[i]->name.text);
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_MOVE, .a = si->vreg, .b = rhsv[i]});
		} else if(lhs[i]->kind == EX_GLOBAL) {
			size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(lhs[i]->name.text));
			*(uint16_t*) &P->abyss[abyss_idx] = strlen(lhs[i]->name.text);
			memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], lhs[i]->name.text, strlen(lhs[i]->name.text));
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETGLOBAL, .a = rhsv[i], .bc = abyss_idx});
		} else if(lhs[i]->kind == EX_INDEX) {
			int lhsv = find_vreg(P);
			assert(lhsv != -1);
			emit_expr(P, lhsv, lhs[i]->A);
			alloc_vreg(P, lhsv);
			
			int keyv = find_vreg(P);
			assert(keyv != -1);
			emit_expr(P, keyv, lhs[i]->B);

			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETFIELD, .a = lhsv, .b = keyv, .c = rhsv[i]});

			free_vreg(P, lhsv);
		} else if(lhs[i]->kind == EX_DOT) {
			int lhsv = find_vreg(P);
			assert(lhsv != -1);
			emit_expr(P, lhsv, lhs[i]->A);
			alloc_vreg(P, lhsv);
			
			Token field = lhs[i]->B_tok;
			
			size_t abyss_idx = abyss_insert(P, NULL, sizeof(uint16_t) + strlen(field.text));
			*(uint16_t*) &P->abyss[abyss_idx] = strlen(field.text);
			memcpy(&P->abyss[abyss_idx + sizeof(uint16_t)], field.text, strlen(field.text));

			int keyv = find_vreg(P);
			assert(keyv != -1);
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETSTR, .a = keyv, .bc = abyss_idx});

			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETFIELD, .a = lhsv, .b = keyv, .c = rhsv[i]});

			free_vreg(P, lhsv);
		} else {
			assert(false);
		}
	}
	
	for(size_t i = 0; i < rhsi; i++) {
		free_vreg(P, rhsv[i]);
	}
	
	return true;
err:
	P->i = old_idx;
	return false;
}

void parse_chunk(Parser *P);

bool parse_stat(Parser *P) {
	if(parse_functiondef(P, true) != -1) {
	} else if(maybe(P, TOK_LOCAL)) {
		vec_Token names = parse_namelist(P);
		
		int i = 0;
		
		if(maybe(P, TOK_EQUAL)) {
			do {
				int vreg = parse_exp(P, -1);
				
				if(i < names.size) {
					alloc_vreg(P, vreg);
					
					ScopeItem *si = calloc(1, sizeof(*si));
					*si = (ScopeItem) {.name = names.data[i], .vreg = vreg};
					
					scope_set_direct(P->scope, si);
				}
				
				i++;
			} while(maybe(P, TOK_COMMA));
		}
		
		for(; i < names.size; i++) {
			int vreg = find_vreg(P);
			alloc_vreg(P, vreg);
			
			ScopeItem *si = calloc(1, sizeof(*si));
			*si = (ScopeItem) {.name = names.data[i], .vreg = vreg};
			
			scope_set_direct(P->scope, si);
		}
		
		vec_Token_drop(&names);
	} else if(maybe(P, TOK_IF)) {
		int vreg = parse_exp(P, -1);
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JNOTCOND, .a = vreg, .bc = 0});
		size_t jump2else = P->current_chunk.instrs.size - 1;
		
		expect(P, TOK_THEN);
		
		parse_chunk(P);
		
		bool isElse = maybe(P, TOK_ELSE);
		
		size_t jump2end;
		if(isElse) {
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JUMP, .a = 0, .bc = 0});
			jump2end = P->current_chunk.instrs.size - 1;
		}
		
		P->current_chunk.instrs.data[jump2else].bc = P->current_chunk.instrs.size - 1 - jump2else;
		
		if(isElse) {
			parse_chunk(P);
			P->current_chunk.instrs.data[jump2end].bc = P->current_chunk.instrs.size - 1 - jump2end;
		}
		
		expect(P, TOK_END);
	} else if(maybe(P, TOK_WHILE)) {
		Expr *condition = desc_exp(P);

		int vreg = find_vreg(P);
		assert(vreg != -1);

		size_t start_idx = P->current_chunk.instrs.size;
		
		emit_expr(P, vreg, condition);

		size_t jump2end = P->current_chunk.instrs.size;
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JNOTCOND, .a = vreg, .bc = 0});

		Scope *new_scope = calloc(1, sizeof(*new_scope));
		new_scope->parent = P->scope;

		expect(P, TOK_DO);
		parse_chunk(P);
		expect(P, TOK_END);

		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JUMP, .a = 0, .bc = start_idx - P->current_chunk.instrs.size - 1});

		P->current_chunk.instrs.data[jump2end].bc = P->current_chunk.instrs.size - 1 - jump2end;
		
		scope_kill(P);
	} else if(maybe(P, TOK_FOR)) {
		if(peek(P, 0).type == TOK_NAME && peek(P, 1).type == TOK_EQUAL) {
			// Range loop
			
			Token name = expect(P, TOK_NAME);
			
			expect(P, TOK_EQUAL);
			
			int fromVreg = parse_exp(P, -1);
			alloc_vreg(P, fromVreg);
			
			expect(P, TOK_COMMA);
			
			int toVreg = parse_exp(P, -1);
			alloc_vreg(P, toVreg);
			
			int stepVreg;
			if(maybe(P, TOK_COMMA)) {
				stepVreg = parse_exp(P, -1);
			} else {
				stepVreg = find_vreg(P);
				vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SETINT16, .a = stepVreg, .bc = 1});
			}
			alloc_vreg(P, stepVreg);
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_SUB, .a = fromVreg, .b = fromVreg, .c = stepVreg});
			
			expect(P, TOK_DO);
			
			Scope *new_scope = calloc(1, sizeof(*new_scope));
			new_scope->parent = P->scope;
			
			ScopeItem *si = calloc(1, sizeof(*si));
			si->name = name;
			si->vreg = fromVreg;
			scope_set_direct(new_scope, si);
			
			P->scope = new_scope;
			
			size_t start_idx = P->current_chunk.instrs.size;
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_ADD, .a = fromVreg, .b = fromVreg, .c = stepVreg});
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_ADVANCETEST, .a = fromVreg, .b = toVreg, .c = stepVreg});
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JUMP, .a = 0, .bc = 0});
			size_t jump2end = P->current_chunk.instrs.size - 1;
			
			parse_chunk(P);
			
			vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_JUMP, .a = 0, .bc = start_idx - P->current_chunk.instrs.size - 1});
			
			P->current_chunk.instrs.data[jump2end].bc = P->current_chunk.instrs.size - 1 - jump2end;
			
			scope_kill(P);
			
			expect(P, TOK_END);
			
			free_vreg(P, fromVreg);
			free_vreg(P, toVreg);
			free_vreg(P, stepVreg);
		} else {
			assert(0 && "Iterator for loop not yet supported");
		}
	} else if(maybe(P, TOK_RETURN)) {
		int vreg = parse_exp(P, -1);
		
		vec_LInst_push(&P->current_chunk.instrs, (LInst) {.opcode = L_RET, .argb = {vreg}});
		
		return false;
	} else if(peek(P, 0).type == TOK_END || peek(P, 0).type == TOK_ELSE || peek(P, 0).type == TOK_ELSEIF || peek(P, 0).type == TOK_EOF) {
		return false;
	} else if(parse_functioncall(P)) {
	} else if(parse_assignment(P)) {
	} else {
		assert(false);
	}
	
	return true;
}

void parse_chunk(Parser *P) {
	while(parse_stat(P));
}

LUnit *lparse(size_t sz, Token *tokens, LTable *environment) {
	LUnit *unit = calloc(1, sizeof(*unit));
	
	Parser P = {
		.i = 0,
		.sz = sz,
		.tokens = tokens,
		
		.environment = environment,
		
		.unit_functions = {},
		
		.scope = calloc(1, sizeof(Scope)),
	};
	
	LFunc func = {};
	func.unit = unit;
	func.is_native = false;
	func.upvalue_count = 0;
	func.env = environment;
	vec_LFunc_push(&P.unit_functions, func);
	
	parse_chunk(&P);
	if(P.current_chunk.instrs.data[P.current_chunk.instrs.size - 1].opcode != L_RET) {
		vec_LInst_push(&P.current_chunk.instrs, (LInst) {.opcode = L_RET, .argb = {0}});
	}
	
	P.unit_functions.data[0].lua_instrs = P.current_chunk.instrs.data;
	
	unit->abyss = P.abyss;
	unit->func_count = 1;
	unit->funcs = P.unit_functions.data;
	
	for(Expr *e = last_desc; e;) {
		Expr *n = e->next_to_die;
		free(e);
		e = n;
	}
	last_desc = NULL;
	
	return unit;
}