#include"value.h"
#include"table.h"
#include"parse.h"
#include"vm.h"
#include"lexer.h"
#include"str.h"
#include"dump.h"
#include<stdatomic.h>
#include<math.h>

static size_t native_print(LVM *lvm, void *ud, size_t argn, set_LValueU *heap, LRegSet *regset) {
	if(lvalue_tag(regset->regs[0]) == LTAG_STRING) {
		LString *lstr = (void*) (regset->regs[0].u & ~LTAG_MASK);
		printf("%.*s\n", (int) lstr->length, lstr->data);
	} else if(lvalue_tag(regset->regs[0]) == LTAG_I32) {
		printf("%i\n", lvalue_to_int32(regset->regs[0]));
	} else if(lvalue_tag(regset->regs[0]) == LTAG_TABLE) {
		printf("table: 0x%lx\n", (uintptr_t) (regset->regs[0].u & ~LTAG_MASK));
	} else if(lvalue_tag(regset->regs[0]) == LTAG_FUNCTION) {
		printf("function: 0x%lx\n", (uintptr_t) (regset->regs[0].u & ~LTAG_MASK));
	} else if(regset->regs[0].u == LTAG_NIL) {
		printf("nil\n");
	} else if(regset->regs[0].u == LTAG_TRUE) {
		printf("true\n");
	} else if(regset->regs[0].u == LTAG_FALSE) {
		printf("false\n");
	} else if(!isnan(regset->regs[0].f)) {
		printf("%f\n", regset->regs[0].f);
	}
	return 0;
}

static size_t table_insert(LVM *lvm, void *ud, size_t argn, set_LValueU *heap, LRegSet *regset) {
	LTable *tbl = (LTable*) (regset->regs[0].u & ~LTAG_MASK);
	ltable_insert(tbl, regset->regs[1], 0);
	return 0;
}

// This function is intended for small-medium runtimes, since the caller thread's heap is not touchable during this call.
static size_t threads_parallel(LVM *lvm, void *ud, size_t argn, set_LValueU *heap, LRegSet *regset) {
	size_t no = lvalue_to_int32(regset->regs[0]);
	LFunc *func = (LFunc*) (regset->regs[1].u & ~LTAG_MASK);
	
	atomic_fetch_sub(&lvm->active_thread_count, 1);
	
	#pragma omp parallel for
	for(size_t i = 0; i < no; i++) {
		LRegSet regset = {};
		lvm_reset_regs(&regset);
		lvm_run(lvm, func, 0, &regset);
	}
	
	atomic_fetch_add(&lvm->active_thread_count, 1);
	
	return 0;
}

static char* read_full_file(const char *fn) {
	FILE *f = fn ? fopen(fn, "rb") : stdin;
	fseek(f, 0, SEEK_END);
	size_t filesize = ftell(f);
	fseek(f, 0, SEEK_SET);
	char *buf = malloc(filesize + 1);
	fread(buf, 1, filesize, f);
	buf[filesize] = '\0';
	if(fn) fclose(f);
	return buf;
}

int main(int argc, char **argv) {
	LTable *env = ltable_new(128);
	
	ltable_set(env,
		lvalue_from_string(lstring_newz("print")),
		lvalue_from_func(lvm_func_from_native(native_print, NULL)));
	
	LTable *table = ltable_new(16);
	{
		ltable_set(table,
			lvalue_from_string(lstring_newz("insert")),
			lvalue_from_func(lvm_func_from_native(table_insert, NULL)));
	}
	ltable_set(env,
		lvalue_from_string(lstring_newz("table")),
		lvalue_from_table(table));
	
	LTable *threads = ltable_new(16);
	{
		ltable_set(threads,
			lvalue_from_string(lstring_newz("parallel")),
			lvalue_from_func(lvm_func_from_native(threads_parallel, NULL)));
	}
	ltable_set(env,
		lvalue_from_string(lstring_newz("threads")),
		lvalue_from_table(threads));
	
	LTable *math = ltable_new(16);
	{
		ltable_set(math, lvalue_from_string(lstring_newz("pi")), (LValue) {.f = 3.141592653589793238463});
	}
	ltable_set(env,
		lvalue_from_string(lstring_newz("math")),
		lvalue_from_table(math));
	
	//const char *bufs = "for i = 1, 10000 do print(i) if i % 3 == 0 then print(\"Fizz\") end if i % 5 == 0 then print(\"Buzz\") end end";
	//const char *bufs = "local t = {a = 9} print(t.a)";
	//const char *bufs = "z = 5 print(z)";
	//const char *bufs = "local i = 0 while i ~= 1500000 do print(i) i = i + 1 end";
	//const char *bufs = "for i = 1, 1000 do print(print) end";
	
	char *bufs = read_full_file(argv[1]);
	
	vec_Token toks = ltokenize(bufs, strlen(bufs));
	
	free(bufs);
	
	LUnit *unit = lparse(toks.size, toks.data, env);
	
	lfreetoks(&toks);

	//dump(unit->funcs[0].lua_instrs);
	
	LVM lvm = {};
	lvm_init(&lvm);
	
	LRegSet regset = {.parent = NULL};
	lvm_reset_regs(&regset);
	lvm_run(&lvm, &unit->funcs[0], 0, &regset);
	
	lvm_destroy(&lvm);
}