#include <windows.h>
#include <tchar.h>
#include "../Calculator.h"
#include "TestHarness.h"

// Feed a sequence of command chars through the engine, threading the
// output string back in as the next input (as the UI does).
static void feed(calc& c, const wchar_t* keys, wchar_t* out) {
    wcscpy(out, L"0");
    wchar_t in[1024];
    for (const wchar_t* p = keys; *p; ++p) {
        wcscpy(in, out);
        c.change_state(*p, in, out);
    }
}

TEST(add) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"2+3=", out);
    EXPECT_WSTR(out, L"5");
    return true;
}

TEST(subtract) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"7-2=", out);
    EXPECT_WSTR(out, L"5");
    return true;
}

TEST(multiply) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"6*7=", out);
    EXPECT_WSTR(out, L"42");
    return true;
}

TEST(divide) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"8/2=", out);
    EXPECT_WSTR(out, L"4");
    return true;
}

TEST(decimal_and_add) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"1.5+1.5=", out);
    EXPECT_WSTR(out, L"3");
    return true;
}

TEST(chained_operations) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"2+3+4=", out);
    EXPECT_WSTR(out, L"9");
    return true;
}

TEST(square_root) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"9Q", out);           // Q = CALC_SQRT
    EXPECT_WSTR(out, L"3");
    return true;
}

TEST(reciprocal) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"4I", out);           // I = CALC_I (inverse, 1/x)
    EXPECT_WSTR(out, L"0.25");
    return true;
}

TEST(percent) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"200*10%", out);      // % = CALC_PERC
    EXPECT_WSTR(out, L"20");
    return true;
}

TEST(negate) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"5P", out);           // P = CALC_NEG
    EXPECT_WSTR(out, L"-5");
    return true;
}

TEST(triple_zero) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"5Z", out);           // Z = CALC_000
    EXPECT_WSTR(out, L"5000");
    return true;
}

TEST(reset) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"123N", out);         // N = CALC_RESET
    EXPECT_WSTR(out, L"0");
    return true;
}

TEST(divide_by_zero) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"5/0=", out);
    EXPECT_WSTR(out, L"Error: division by zero");
    return true;
}

TEST(overflow) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"99999999999999999999999999", out);  // 26 digits > MAX_LEN_RESULT (25)
    EXPECT_WSTR(out, L"Error: overflow");
    return true;
}

TEST(euro_key_is_noop) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"5R", out);   // R = CALC_EURO (removed) -> must not convert
    EXPECT_WSTR(out, L"5");
    return true;
}

TEST(hex_toggle_key_is_noop) {
    calc c; c.set_precision(2);
    wchar_t out[1024];
    feed(c, L"255X", out); // X = CALC_X (removed) -> stays decimal text
    EXPECT_WSTR(out, L"255");
    return true;
}

int wmain() { return run_all(); }