#include <stdlib.h>
#include <assert.h>
#include "ir.h"


struct ir* ir_make(void) {
	struct ir *ir = malloc(sizeof(struct ir));
	ir->cap = 32;
	ir->len = 0;
	ir->inss = malloc(ir->cap * sizeof(struct irins*));
	ir->globspace = 0;
	return ir;
}

void ir_delete(struct ir *ir) {
	for (int i = 0; i < ir->len; i++) {
		irins_delete(ir->inss[i]);
	}
	free(ir->inss);
	free(ir);
}

void ir_print(struct ir *ir, FILE *f) {
	fprintf(f, "IR [globspace=%d]\n", ir->globspace);
	for (int i = 0; i < ir->len; i++) {
		irins_print(ir->inss[i], f);
	}
}

static const char* condcode_show(enum condcode condcode) {
	switch (condcode) {
		case CCZ: return "z";
		case CCNZ: return "nz";
		case CCL: return "l";
		case CCG: return "g";
		case CCLE: return "le";
		case CCGE: return "ge";
		default: assert(false);
	}
}

static const char* ref_show(struct ref ref) {
	static char cbuf[3][16];
	static int cbufi = 0;
	static const char *special[8] = {"A", "B", "C", "D", "X", "Y", "SP", "BP"};

	const char *suffix;
	if (ref.rel == REFREL_ZERO) suffix = "";
	else if (ref.rel == REFREL_DATA) suffix = ":data";
	else if (ref.rel == REFREL_HEAP) suffix = ":heap";
	else assert(false);

	switch (ref.type) {
		case REF_REG:
			if (ref.reg == REG_UNUSED) return "<<UNUSED?>>";
			if (ref.reg < 0) return special[-(ref.reg - REG_A)];
			cbufi = (cbufi + 1) % 3;
			sprintf(cbuf[cbufi], "t%d", ref.reg);
			return cbuf[cbufi];

		case REF_MEM:
			cbufi = (cbufi + 1) % 3;
			if (ref.reg == REG_UNUSED) {
				sprintf(cbuf[cbufi], "[%d%s]", ref.offset, suffix);
			} else if (ref.reg < 0) {
				sprintf(cbuf[cbufi], "[%s + %d%s]", special[-(ref.reg - REG_A)], ref.offset, suffix);
			} else {
				sprintf(cbuf[cbufi], "[t%d + %d%s]", ref.reg, ref.offset, suffix);
			}
			return cbuf[cbufi];

		case REF_IMM:
			cbufi = (cbufi + 1) % 3;
			sprintf(cbuf[cbufi], "%d", ref.imm);
			return cbuf[cbufi];

		default:
			assert(false);
	}
}

void irins_print(struct irins *ins, FILE *f) {
	switch (ins->type) {
		case INS_ADD: fprintf(f, "\t%s <- %s + %s\n", ref_show(ins->r0), ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_SUB: fprintf(f, "\t%s <- %s - %s\n", ref_show(ins->r0), ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_MUL: fprintf(f, "\t%s <- %s * %s\n", ref_show(ins->r0), ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_DIV: fprintf(f, "\t%s <- %s / %s\n", ref_show(ins->r0), ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_MOD: fprintf(f, "\t%s <- %s %% %s\n", ref_show(ins->r0), ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_NEG: fprintf(f, "\t%s <- -%s\n", ref_show(ins->r0), ref_show(ins->r1)); break;
		case INS_NOT: fprintf(f, "\t%s <- !%s\n", ref_show(ins->r0), ref_show(ins->r1)); break;
		case INS_TEST: fprintf(f, "\ttest %s, %s\n", ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_PUSH: fprintf(f, "\tpush %s\n", ref_show(ins->r1)); break;
		case INS_POP: fprintf(f, "\t%s = pop\n", ref_show(ins->r0)); break;
		case INS_CMP: fprintf(f, "\tcmp %s, %s\n", ref_show(ins->r1), ref_show(ins->r2)); break;
		case INS_LBL: fprintf(f, "%s:\n", ins->name); break;
		case INS_JMP: fprintf(f, "\tjmp %s\n", ins->name); break;
		case INS_JCC: fprintf(f, "\tj%s %s\n", condcode_show(ins->condcode), ins->name); break;
		case INS_CALL: fprintf(f, "\tcall %s\n", ins->name); break;
		case INS_CALLV: fprintf(f, "\t%s <- call %s\n", ref_show(ins->r0), ins->name); break;
		case INS_RET: fprintf(f, "\tret\n"); break;
		case INS_RETV: fprintf(f, "\tret %s\n", ref_show(ins->r1)); break;
		case INS_MOV: fprintf(f, "\t%s <- %s\n", ref_show(ins->r0), ref_show(ins->r1)); break;
		default: assert(false);
	}
}

struct ref ir_reserve_global(struct ir *ir, int size) {
	int offset = ir->globspace;
	ir->globspace += size;
	return ref_mem(REG_UNUSED, offset, REFREL_DATA);
}

void ir_append(struct ir *ir, struct irins *ins) {
	if (ir->len == ir->cap) {
		ir->cap *= 2;
		ir->inss = realloc(ir->inss, ir->cap * sizeof(struct irins*));
	}
	ir->inss[ir->len++] = ins;
}

struct irins* irins_make(enum instype type) {
	struct irins *ins = malloc(sizeof(struct irins));
	ins->type = type;
	ins->name = NULL;
	return ins;
}

struct irins* irins_make_name(enum instype type, char *name) {
	struct irins *ins = irins_make(type);
	ins->name = name;
	return ins;
}

struct irins* irins_make_0(enum instype type, struct ref r0) {
	struct irins *ins = irins_make(type);
	ins->r0 = r0;
	return ins;
}

struct irins* irins_make_01(enum instype type, struct ref r0, struct ref r1) {
	struct irins *ins = irins_make(type);
	ins->r0 = r0;
	ins->r1 = r1;
	return ins;
}

struct irins* irins_make_012(enum instype type, struct ref r0, struct ref r1, struct ref r2) {
	struct irins *ins = irins_make_01(type, r0, r1);
	ins->r2 = r2;
	return ins;
}

struct irins* irins_make_1(enum instype type, struct ref r1) {
	struct irins *ins = irins_make(type);
	ins->r1 = r1;
	return ins;
}

struct irins* irins_make_12(enum instype type, struct ref r1, struct ref r2) {
	struct irins *ins = irins_make(type);
	ins->r1 = r1;
	ins->r2 = r2;
	return ins;
}

struct irins* irins_make_jcc(char *name, enum condcode condcode) {
	struct irins *ins = irins_make(INS_JCC);
	ins->name = name;
	ins->condcode = condcode;
	return ins;
}

void irins_delete(struct irins *ins) {
	if (ins->name) free(ins->name);
	free(ins);
}

char* gen_label_name(void) {
	static int next = 0;
	char *buf = malloc(16);
	sprintf(buf, "L%d", next++);
	return buf;
}

struct ref ref_reg(int reg) {
	return (struct ref){REF_REG, reg, 0, REFREL_ZERO, 0};
}

struct ref ref_mem(int reg, int offset, enum refrel rel) {
	return (struct ref){REF_MEM, reg, offset, rel, 0};
}

struct ref ref_imm(int imm) {
	return (struct ref){REF_IMM, REG_UNUSED, 0, REFREL_ZERO, imm};
}

struct ref ref_next_register(void) {
	static int next = 0;
	return ref_reg(next++);
}