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/**
 * An old "scroll-able log" I made when I first learnt Windows programming.
 * Very basic and not really useful, but took me a long time to figure out
 * the auto size expansion, dynamic memory management, syncing, wide string stuff,
 * and so on, so want to keep it somewhere.
 *
 * Combined dsm-log.c and dsm-log.rc to save space and reduce contex switching
 */

#include <windows.h>
#include <stdio.h>

#ifndef UNICODE
#define UNICODE
#endif

#define N_SHOWN 1    /* how many messages to show at the same time */
#define S_TEST L"[Hit Test a few times]"
#define CLASS_LOGSCROLLABLE L"LogScrollable"
#define MAX_LEN_MSG 32

void *Zalloc(size_t len) {
    void *p = malloc(len);
    if (p==NULL) {
        perror("Error calling malloc()\n");
    }
    return(p);
}
void KlasWOld(HWND hWnd, CHAR *snle, size_t lenSnle) {
    WCHAR *sZof = Zalloc((lenSnle+1)*sizeof(WCHAR));
    MultiByteToWideChar(CP_UTF8, 0, snle, lenSnle, sZof, lenSnle);
    sZof[lenSnle] = '\0';
    SetWindowTextW(hWnd, sZof);
    free(sZof);
}
void KlasW(HWND hTarget, LPWSTR sMsg) {
    SetWindowTextW(hTarget, sMsg);
}


enum tag_TEST_ID {
    IDB_TEST_ADD_MSG = 101, IDB_TEST_CLEAR, IDB_TEST_EXIT
};
enum tag_LS_ID {
    IDB_PREV = 190, IDB_NEXT = 191, IDB_LAST = 192
};
enum tag_TAQ {
    L_WIDTH = 40, L_HEIGHT = 20, L_TEXT = 200,
    LS_X_CONTROLS = 10, LS_Y_CONTROL_TOP = 10 + N_SHOWN * L_HEIGHT,
    LS_X_MSGS = 10 + L_WIDTH, LS_Y_MSG_TOP = 10 + L_HEIGHT
};


/* -- tyeps -- */
typedef struct tag_LOGSCROLLABLE {
    HWND hCurrent;
    HWND hCurIndex;
    HWND hButtonPrev;
    HWND hButtonNext;
    int index;
    BOOL isAutoScroll;    /* auto-scroll on/of */
    int capMsgs;    /* capacity */
    int nMsgs;
    LPWSTR *listMsgs;
} LOGSCROLLABLE, *PLOGSCROLLABLE;


void LS_Init(PLOGSCROLLABLE logData) {
    logData->capMsgs = 8;
    logData->index = 0;
    logData->isAutoScroll = TRUE;
    logData->nMsgs = 0;
    logData->listMsgs = (LPWSTR *) Zalloc((logData->capMsgs)*sizeof(LPVOID));
    printf("<LS I.> init'd\n");
}
void LS_Expand(PLOGSCROLLABLE logData) {
    printf("<LS E.> attempting to expand capacity...\n");
    int newCapMsgs = 3 * (logData->capMsgs) / 2;
    logData->listMsgs = (LPWSTR *) realloc(logData->listMsgs, newCapMsgs*sizeof(LPVOID));
    if (logData->listMsgs==NULL) { perror("realloc() failed\n"); }
    logData->capMsgs = newCapMsgs;
    printf("<LS E.> expanded capacity to %d\n", newCapMsgs);
}


void LS_CreateWindows(PLOGSCROLLABLE logData, HWND hWnd) {
    HINSTANCE hInst = (HINSTANCE) GetWindowLongPtr(hWnd, GWLP_HINSTANCE);
    logData->hCurrent = CreateWindowW(L"Static", S_TEST, WS_CHILD | WS_VISIBLE,
        LS_X_MSGS, LS_Y_MSG_TOP, L_TEXT, L_HEIGHT,
        hWnd, NULL, hInst, NULL);
    logData->hButtonPrev = CreateWindowW(L"Button", L"Prev", WS_CHILD | WS_VISIBLE,
        LS_X_CONTROLS, LS_Y_CONTROL_TOP+0*L_HEIGHT, L_WIDTH, L_HEIGHT,
        hWnd, (HMENU) IDB_PREV, hInst, NULL);
    logData->hCurIndex = CreateWindowW(L"Static", L"#", WS_CHILD | WS_VISIBLE,
        LS_X_CONTROLS, LS_Y_CONTROL_TOP+1*L_HEIGHT, L_WIDTH, L_HEIGHT,
        hWnd, NULL, hInst, NULL);
    logData->hButtonNext = CreateWindowW(L"Button", L"Next", WS_CHILD | WS_VISIBLE,
        LS_X_CONTROLS, LS_Y_CONTROL_TOP+2*L_HEIGHT, L_WIDTH, L_HEIGHT,
        hWnd, (HMENU) IDB_NEXT, hInst, NULL);
    CreateWindowW(L"Button", L"Latest", WS_CHILD | WS_VISIBLE,
        LS_X_CONTROLS, LS_Y_CONTROL_TOP+3*L_HEIGHT, L_WIDTH, L_HEIGHT,
        hWnd, (HMENU) IDB_LAST, hInst, NULL);
    CreateWindowW(L"Button", L"exit", WS_CHILD | WS_VISIBLE,
        240, 0, 40, 20, hWnd, (HMENU) IDB_TEST_EXIT, NULL, NULL);
    CreateWindowW(L"Button", L"test", WS_CHILD | WS_VISIBLE,
        240, 20, 40, 20, hWnd, (HMENU) IDB_TEST_ADD_MSG, NULL, NULL);
    printf("<LS C.W.> created windows\n");
}

void LS_Scroll(PLOGSCROLLABLE logData, WPARAM wParam) {
    if (logData->nMsgs==0) {
        return;
    }

    switch (wParam) {
    case IDB_PREV:
        logData->isAutoScroll = FALSE;    /* auto-scroll off */
        logData->index--;
        break;
    case IDB_NEXT:
        logData->index++;
        break;
    case IDB_LAST:
        logData->isAutoScroll = TRUE;    /* auto-scroll on */
        logData->index = logData->nMsgs - 1;
        break;
    default:
        /* need this to manually update sIndex */
        break;
    }

    if ((logData->index) < 0) {
        MessageBeep(MB_ICONWARNING);
        logData->index = 0;
    }
    if ((logData->index) > (logData->nMsgs)-1) {
        MessageBeep(MB_ICONWARNING);
        logData->index = logData->nMsgs - 1;
    }

    LPWSTR sIndex = (LPWSTR) Zalloc(10*sizeof(LPVOID));
    wsprintfW(sIndex, L"%d/%d", logData->index+1, logData->nMsgs);
    KlasW(logData->hCurIndex, sIndex);
    KlasW(logData->hCurrent, logData->listMsgs[logData->index]);
    free(sIndex);
}

void LS_AddMsg(PLOGSCROLLABLE logData, LPWSTR sMsg) {
    /* we need vwsprintf, right prlxvalue? */
    LPWSTR sMsgInList = (LPWSTR) Zalloc(MAX_LEN_MSG*sizeof(WCHAR));
    wcsncpy(sMsgInList, sMsg, MAX_LEN_MSG);
    sMsgInList[0] = (SHORT) (logData->nMsgs + 'B');
    /* too lazy to generate actually plausible messages */
    sMsgInList[MAX_LEN_MSG-1] = L'\0';

    logData->listMsgs[logData->nMsgs] = sMsgInList;
    logData->nMsgs++;

    LS_Scroll(logData, (WPARAM) 0);    /* set new text */
    if (logData->isAutoScroll) {
        logData->index++;
    }

    if ((logData->nMsgs) > (logData->capMsgs - 5)) {
        LS_Expand(logData);
    }

    //for (int i=0; i<logData->nMsgs; i++) {
    //wprintf(L"%p is %s\n", logData->listMsgs[i], logData->listMsgs[i]);
    //}

}
void LS_Cleanup(PLOGSCROLLABLE logData) {
    for (int i=0; i<logData->nMsgs; i++) {
        if (logData->listMsgs[i]) {
            free(logData->listMsgs[i]);
        }
    }
    free(logData->listMsgs);
    free(logData);
    printf("<LS C.> Cleanup done!\n");
}

void LS_ButtonControl(PLOGSCROLLABLE logData, HWND hWnd, WPARAM wParam) {
    switch (wParam) {
    case IDB_PREV:
    case IDB_NEXT:
    case IDB_LAST:
        LS_Scroll(logData, wParam);
        break;
    case IDB_TEST_EXIT:
        SendMessageW(hWnd, WM_DESTROY, (WPARAM) NULL, (LPARAM) NULL);
        break;
    case IDB_TEST_ADD_MSG:
        LS_AddMsg(logData, L"*ary says hi");
        break;
    }
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT wmsg, WPARAM wParam, LPARAM lParam) {
    static PLOGSCROLLABLE logData = NULL;

    switch (wmsg) {
    case WM_CREATE:
        logData = (PLOGSCROLLABLE) Zalloc(sizeof(LOGSCROLLABLE));
        LS_Init(logData);
        LS_CreateWindows(logData, hWnd);
        break;
    case WM_COMMAND:
        LS_ButtonControl(logData, hWnd, wParam);
        break;
    case WM_ERASEBKGND:
        break;    /* allegd fix for flashing */
    case WM_DESTROY:
        LS_Cleanup(logData);
        PostQuitMessage(0);
        break;
    }
    return(DefWindowProcW(hWnd, wmsg, wParam, lParam));
}
int APIENTRY WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmdLine, int nCmdShow) {
    WNDCLASSW wc = {0};
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInst;
    wc.lpszClassName = CLASS_LOGSCROLLABLE;
    RegisterClassW(&wc);
    HWND hWnd;    /* "HWND hWnd;" indeed */
    hWnd = CreateWindowW(CLASS_LOGSCROLLABLE, L"Log", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 300, 300, NULL, NULL, hInst, NULL);
    ShowWindow(hWnd, nCmdShow);
    MSG windowMsg = {0};
    while (GetMessage(&windowMsg, NULL, 0, 0)) {
        TranslateMessage(&windowMsg);
        DispatchMessage(&windowMsg);
    }
    return(0);
}