#include <exception>
#include <sstream>
#include <windows.h>
#include <commctrl.h>
#include <uxtheme.h>
#include <SWI-Prolog.h>

#include "resource.h"
#include "common.h"
#include "datalistview.h"
#include "episodelistview.h"
#include "main.h"
#include "pl.h"

/* Looked-up constants. */
int g_bThemes;
int g_iDPI = 96;

/* Fonts. */
HFONT g_hfNormal;
HFONT g_hfBold;

/* Menus. */
HMENU g_hPopupMenu;

/* Windows. */
HWND g_hWndFocus;
HWND g_hWnd;
HWND g_hWndStatus;

/* Child window objects. */
DataListView* g_pDlv;
EpisodeListView* g_pElv;

/* View settings. */
int g_bViewWatched = 1;
int g_bViewTVOriginal = 1;
char g_szLimitScreenwriter[64];

static LRESULT CALLBACK CBTProc(int, WPARAM, LPARAM);
static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
void WndProcMainMenu(const HWND, unsigned short);
void WndProcContextMenu(const HWND, unsigned short);
static void WaitFor(const char*, const char*);
static INT_PTR CALLBACK AboutDlgProc(HWND, UINT, WPARAM, LPARAM);
static void UpdateTheme();

void TerminateMsg(const wchar_t* wsz1, const wchar_t* wsz2) noexcept
{
	std::wstringstream wss;
	wss << L"Episode Browser was terminated due to ";
	wss << wsz1;
	if (wsz2)
		wss << ": " << wsz2;
	else
		wss << ".";
	MessageBox(g_hWnd, wss.str().c_str(), L"Fatal Error", MB_ICONERROR);
}

void OnTerminate() noexcept
{
	try {
		std::rethrow_exception(std::current_exception());
        } catch (const term_t& t) {
		std::wstring ws;
		if (PlString(t, &ws))
			TerminateMsg(L"a Prolog exception", ws.c_str());
		else
			TerminateMsg(L"a Prolog exception", NULL);
	} catch (const Win32Error& e) {
		TerminateMsg(L"a Windows error", e.WhatW());
	} catch (const std::exception& e) {
		TerminateMsg(L"an exception", WsFromSz(e.what()).c_str());
	} catch (...) {
		TerminateMsg(L"an exception", NULL);
	}
	_Exit(1);
}

int WINAPI WinMain(const HINSTANCE hInstance, const HINSTANCE, char* const, const int nCmdShow)
{
	/* Exit gracefully on uncaught exception. */
	std::set_terminate(OnTerminate);

	/* Initialize Prolog. */
	char* argv[] = { (char*)"EpisodeBrowser", NULL };
	if (!PL_initialise(1, argv))
		throw std::runtime_error("Could not initialize Prolog.");
	if (!Pl("track_episodes","attach") || !Pl("episode_data","attach"))
		throw std::runtime_error("Could not attach databases.");

	/* Initialize common controls, load menu and register window class. */
	INITCOMMONCONTROLSEX icc;
	icc.dwSize = sizeof(icc);
	icc.dwICC = ICC_WIN95_CLASSES;
	require(InitCommonControlsEx(&icc));

	g_hPopupMenu = require(LoadMenu((HINSTANCE)NULL, MAKEINTRESOURCE(IDR_POPUPMENU)));
	g_hPopupMenu = require(GetSubMenu(g_hPopupMenu, 0));

	WNDCLASSEX wc;
	memset(&wc, 0, sizeof(WNDCLASSEX));
	wc.cbSize	 = sizeof(WNDCLASSEX);
	wc.lpfnWndProc	 = WndProc;
	wc.hInstance	 = hInstance;
	wc.hIcon	 = LoadIcon(NULL, IDI_APPLICATION);
	wc.hCursor	 = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
	wc.lpszMenuName	 = MAKEINTRESOURCE(IDR_MENU);
	wc.lpszClassName = L"Episode Browser";
	wc.hIconSm	 = LoadIcon(NULL, IDI_APPLICATION);
	require(RegisterClassEx(&wc));

	/* Create window. A CBT hook is used to initialize important
	 * global variables before any messages are sent to the new
	 * window. It is vital that the hook is set up correctly. */
	const HHOOK hHook = require(SetWindowsHookEx(WH_CBT, CBTProc,
	    (HINSTANCE)NULL, GetCurrentThreadId()));
	const HWND hWnd = require(CreateWindowEx(
	    0,
	    L"Episode Browser",
	    L"Episode Browser",
	    WS_OVERLAPPEDWINDOW|WS_CLIPCHILDREN,
	    CW_USEDEFAULT, CW_USEDEFAULT, 0, 0,
	    (HWND)NULL, (HMENU)NULL, hInstance, (void*)NULL));
	require(UnhookWindowsHookEx(hHook));

	g_hWndStatus = require(CreateWindowEx(
	    0,
	    STATUSCLASSNAME,
	    (const wchar_t*)NULL,
	    WS_CHILD|WS_VISIBLE|SBARS_SIZEGRIP,
	    0, 0, 0, 0,
	    hWnd, (HMENU)IDR_STATUS, hInstance, (void*)NULL));

	ShowWindow(hWnd, nCmdShow);

	/* Populate episode list view. */
	Pl("track_episodes","update_tracked_episodes");
	g_pElv->Update();
	g_pElv->RestoreFocus();

	MSG msg;
	while (GetMessage(&msg, NULL, 0, 0) > 0) {
		if (IsDialogMessage(hWnd, &msg)) continue;
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	PL_halt(0);
	return 0;
}

static LRESULT CALLBACK CBTProc(const int nCode, const WPARAM wParam, const LPARAM lParam)
{
	if (nCode < 0 || nCode != HCBT_CREATEWND || g_hWnd)
		return CallNextHookEx(0, nCode, wParam, lParam);

	/* This code is run ONCE, at the creation of the top-level
	 * window -- before WndProc! This is important, as it
	 * initializes global variables that are used by WndProc. */

	g_hWnd = (HWND)wParam;

	/* Look up constants. */
	if (auto opLib = maybe_make<Library>(L"User32.dll");
	    auto GetDpiForWindow = opLib->GetProcAddress<UINT(HWND)>("GetDpiForWindow"))
		g_iDPI = GetDpiForWindow(g_hWnd);

	if (auto opLib = maybe_make<Library>(L"uxtheme.dll");
	    opLib->GetProcAddress<void>("SetWindowTheme"))
		g_bThemes = 1;

	if (auto opLib = maybe_make<Library>(L"User32.dll");
	    opLib->GetProcAddress<void>("SystemParametersInfo" WA)) {
		NONCLIENTMETRICS m;
		m.cbSize = sizeof(NONCLIENTMETRICS);
		require(SystemParametersInfo(SPI_GETNONCLIENTMETRICS,
		    sizeof(NONCLIENTMETRICS), &m, 0));
		g_hfNormal = require(CreateFontIndirect(&m.lfMessageFont));
	} else
		g_hfNormal = static_cast<HFONT>(require(GetStockObject(DEFAULT_GUI_FONT)));

	LOGFONT lf;
	require(GetObject(g_hfNormal, sizeof(LOGFONT), &lf));
	lf.lfWeight = FW_BOLD;
	g_hfBold = require(CreateFontIndirect(&lf));

	/* Create child windows. */
	g_pDlv = new DataListView(g_hWnd);
	g_pElv = new EpisodeListView(g_hWnd);

	/* Get saved view settings. */
	char* sz;
	Pl("cfg","get_view_watched",&g_bViewWatched);
	Pl("cfg","get_view_tv_original",&g_bViewTVOriginal);
	if (Pl("cfg","get_limit_screenwriter",&sz))
		strcpy_s(g_szLimitScreenwriter, sizeof(g_szLimitScreenwriter), sz);
	return 0;
}

LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam, LPARAM lParam)
{
	switch (uMsg) {
	case WM_CREATE:
		UpdateTheme();
		SetWindowPos(hWnd, NULL, -1, -1, Dpi(510), Dpi(412), SWP_NOZORDER|SWP_NOMOVE|SWP_NOACTIVATE);
		SetFocus(g_pElv->hWnd);

		/* Set menu item checkmarks according to saved settings. */
		CheckMenuItem(GetMenu(hWnd), IDM_VIEW_WATCHED,
		    g_bViewWatched? MF_CHECKED: MF_UNCHECKED);
		CheckMenuItem(GetMenu(hWnd), IDM_VIEW_TV_ORIGINAL,
		    g_bViewTVOriginal? MF_CHECKED: MF_UNCHECKED);
		CheckMenuItem(GetMenu(hWnd), IDM_VIEW_OTHERS,
		    g_szLimitScreenwriter[0]? MF_UNCHECKED: MF_CHECKED);
		break;
	case WM_CLOSE:
		DestroyWindow(hWnd);
		break;
	case WM_DESTROY:
		g_pElv->SaveFocus();
		PostQuitMessage(0);
		break;
	case WM_SIZE:
		SendMessage(g_hWndStatus, WM_SIZE, wParam, lParam);
		UpdateLayout(LOWORD(lParam), HIWORD(lParam));
		break;
	case WM_GETMINMAXINFO:
	    {
		MINMAXINFO* const pMMI = (MINMAXINFO*)lParam;
		pMMI->ptMinTrackSize.x = Dpi(220);
		pMMI->ptMinTrackSize.y = Dpi(220);
		break;
	    }
	case WM_THEMECHANGED:
		UpdateTheme();
		UpdateLayout();
		break;
	case 0x02E0: /* WM_DPICHANGED */
	    {
		const RECT* const lpr = (RECT*)lParam;
		g_iDPI = HIWORD(wParam);
		prefer(SetWindowPos(hWnd, (HWND)NULL,
		    lpr->left, lpr->top,
		    lpr->right-lpr->left,
		    lpr->bottom-lpr->top,
		    SWP_NOZORDER|SWP_NOACTIVATE));
		UpdateLayout(lpr->right-lpr->left, lpr->bottom-lpr->top);
		break;
	    }
	case WM_ACTIVATE:
		switch (wParam) {
		case WA_INACTIVE:
			g_hWndFocus = GetFocus();
			break;
		case WA_ACTIVE:
		case WA_CLICKACTIVE:
			SetFocus(g_hWndFocus);
			Pl("track_episodes","update_tracked_episodes");
			g_pElv->Redraw();
		}
		break;
	case WM_NOTIFY:
		switch (((NMHDR*)lParam)->idFrom) {
		case IDC_EPISODELISTVIEW:
			return g_pElv->HandleNotify(lParam);
		}
		break;
	case WM_COMMAND:
	    {
		const unsigned short wCommand = LOWORD(wParam);
		switch (ID_GROUP(wCommand)) {
		case IDG_MENU:
			WndProcMainMenu(hWnd, wCommand);
			break;
		case IDG_CTX:
			WndProcContextMenu(hWnd, wCommand);
			break;
		}
		break;
	    }
	case WM_MENUSELECT:
	    {
		/* Look up status bar help for menu command. The help
		 * strings are stored in arrays, whose indices
		 * correspond to the IDM_ values (see resource.h). */

		static const wchar_t* aWszMenu[] = {
			/*IDM_FILE_EXIT*/L"Close Episode Browser.",
			/*IDM_FILE_REFRESH*/L"Quickly refresh episode list.",
			/*IDM_FILE_FETCH_DATA*/L"Fetch episode data from the web (may take a few seconds).",
			/*IDM_FILE_FETCH_SCREENWRITERS*/L"Fetch screenwriters from the web (may take a minute).",
			/*IDM_FILE_ABOUT*/L"Show information about Episode Browser.",
			/*IDM_VIEW_WATCHED*/L"Show/hide watched episodes.",
			/*IDM_VIEW_TV_ORIGINAL*/L"Show/hide TV original episodes.",
			/*IDM_VIEW_OTHERS*/L"Show/hide episodes by other screenwriters."
		};
		static const wchar_t* aWszCtx[] = {
			/*IDM_WATCH_LOCALLY*/L"Open local copy of episode, if available.",
			/*IDM_WATCH_ONLINE*/L"Open episode in the web browser.",
			/*IDM_TOGGLE*/L"Toggle watched/unwatched status.",
			/*IDM_FORGET*/L"Reset watched/unwatched status.",
			/*IDM_LOOKUP*/L"Fetch episode data from the web, such as date, source and hint.",
			/*IDM_WIKI*/L"Show Detective Conan Wiki entry for episode.",
			/*IDM_RATE0*/L"Remove episode rating.",
			/*IDM_RATE1*/L"Rate episode 1/10.",
			/*IDM_RATE2*/L"Rate episode 2/10.",
			/*IDM_RATE3*/L"Rate episode 3/10.",
			/*IDM_RATE4*/L"Rate episode 4/10.",
			/*IDM_RATE5*/L"Rate episode 5/10.",
			/*IDM_RATE6*/L"Rate episode 6/10.",
			/*IDM_RATE7*/L"Rate episode 7/10.",
			/*IDM_RATE8*/L"Rate episode 8/10.",
			/*IDM_RATE9*/L"Rate episode 9/10.",
			/*IDM_RATE10*/L"Rate episode 10/10."
		};

		const unsigned short wCommand = LOWORD(wParam);
		const unsigned short wGroup = ID_GROUP(wCommand);
		const wchar_t* wsz = {0};
		if (wGroup) {
			const wchar_t** aWsz = wGroup==IDG_MENU? aWszMenu: aWszCtx;
			wsz = aWsz[ID_INDEX(wCommand)];
		}
		SendMessage(g_hWndStatus, SB_SETTEXT, MAKEWPARAM(0,0), (LPARAM)wsz);
		break;
	    }
	default:
		return DefWindowProc(hWnd, uMsg, wParam, lParam);
	}

	return 0;
}

/* Process main menu commands. */
void WndProcMainMenu(const HWND hWnd, unsigned short wCommand)
{
	switch (wCommand) {
	case IDM_FILE_EXIT:
		PostMessage(hWnd, WM_CLOSE, 0, 0);
		break;
	case IDM_FILE_REFRESH:
		g_pElv->Update();
		break;
	case IDM_FILE_FETCH_DATA:
		WaitFor("episode_data","update_episode_data");
		break;
	case IDM_FILE_FETCH_SCREENWRITERS:
		WaitFor("episode_data","update_screenwriters");
		break;
	case IDM_FILE_ABOUT:
		DialogBox(
		    GetModuleHandle(NULL),
		    MAKEINTRESOURCE(IDD_ABOUT),
		    hWnd,
		    AboutDlgProc
		);
		break;
	case IDM_VIEW_WATCHED:
		CheckMenuItem(GetMenu(hWnd), IDM_VIEW_WATCHED,
		    g_bViewWatched? MF_UNCHECKED: MF_CHECKED);
		g_bViewWatched = !g_bViewWatched;
		Pl("cfg","set_view_watched",g_bViewWatched);
		g_pElv->Update();
		g_pElv->EnsureFocusVisible();
		break;
	case IDM_VIEW_TV_ORIGINAL:
		CheckMenuItem(GetMenu(hWnd), IDM_VIEW_TV_ORIGINAL,
		    g_bViewTVOriginal? MF_UNCHECKED: MF_CHECKED);
		g_bViewTVOriginal = !g_bViewTVOriginal;
		Pl("cfg","set_view_tv_original",g_bViewTVOriginal);
		g_pElv->Update();
		g_pElv->EnsureFocusVisible();
		break;
	case IDM_VIEW_OTHERS:	/* Show/hide other screenwriters. */
		if (g_szLimitScreenwriter[0]) {
			CheckMenuItem(GetMenu(hWnd), IDM_VIEW_OTHERS,
			    MF_CHECKED);
			g_szLimitScreenwriter[0] = 0;
		} else {
			const int iEpFocus = ListView_GetNextItem(g_pElv->hWnd, -1, LVNI_FOCUSED);
			if (iEpFocus == -1) break;

			LVITEM lvi;
			lvi.iItem = iEpFocus;
			lvi.mask = LVIF_PARAM;
			if (!ListView_GetItem(g_pElv->hWnd, &lvi)) break;

			char* sz;
			if (!Pl("episode_data","episode_datum",lvi.lParam,"Screenwriter",&sz))
				break;
			strcpy_s(g_szLimitScreenwriter,
			    sizeof(g_szLimitScreenwriter), sz);
			CheckMenuItem(GetMenu(hWnd), IDM_VIEW_OTHERS,
			    MF_UNCHECKED);
		}
		Pl("cfg","set_limit_screenwriter",g_szLimitScreenwriter);
		g_pElv->Update();
		g_pElv->EnsureFocusVisible();
		break;
	}
}

/* Process context menu commands. */
void WndProcContextMenu(const HWND, unsigned short wCommand)
{
	LVITEM lvi;
	int cNotFound = 0;

	/* Look through selected items, applying the
	 * selected command to each one. */

	lvi.mask = LVIF_PARAM;
	lvi.iItem = -1;
	while ((lvi.iItem = ListView_GetNextItem(g_pElv->hWnd, lvi.iItem, LVNI_SELECTED)) != -1
	    && ListView_GetItem(g_pElv->hWnd, &lvi)) {

		/* Process rate commands. */
		if (ID_SUBGROUP(wCommand) == IDG_CTX_RATE) {
			Pl("episode_data","rate_episode",lvi.lParam,ID_RATING(wCommand));
			g_pElv->UpdateItem(&lvi);
			continue;
		}

		/* Process other commands. */
		switch (wCommand) {
		case IDM_WATCH_LOCALLY:
			if (!Pl("local_episode","open_episode_locally",lvi.lParam))
				cNotFound++;
			break;
		case IDM_WATCH_ONLINE:
			Pl("local_episode","open_episode_online",lvi.lParam);
			break;
		case IDM_TOGGLE:
			Pl("track_episodes","toggle_episode",lvi.lParam);
			break;
		case IDM_FORGET:
			Pl("track_episodes","forget_episode",lvi.lParam);
			Pl("track_episodes","update_tracked_episodes");
			break;
		case IDM_LOOKUP:
			Pl("episode_data","retract_episode",lvi.lParam);
			g_pElv->UpdateItem(&lvi);
			g_pDlv->ShowEpisode(lvi.lParam);
			break;
		case IDM_WIKI:
			Pl("episode_data","open_episode_wiki",lvi.lParam);
			break;
		}
	}

	g_pElv->Redraw();
	if (cNotFound == 1) {
		EBMessageBox(L"Episode could not be opened locally.",
		    L"Error", MB_ICONWARNING);
	} else if (cNotFound) {
		std::wstringstream wss;
		wss << cNotFound << L" episodes could not be opened locally.";
		EBMessageBox(wss.str().c_str(), L"Error", MB_ICONWARNING);
	} else if (ID_SUBGROUP(wCommand) == IDG_CTX_RATE) {
		g_pElv->Sort();
		g_pElv->ShowFocus();
	}
}

/* Call Prolog predicate in other thread, if available. */
void WaitFor(const char* szMod, const char* szPred)
{
	static atom_t aThread;
	static int bActive;
	static int iTimer;
	static std::wstring wsPred;

	if (bActive) {
		std::wstringstream wss;
		wss << L"Another task (" << wsPred.c_str() << ") is active. "
		    << "Do you want to cancel the existing task and start a new one?";
		if (EBMessageBox(wss.str().c_str(), L"Error", MB_YESNO|MB_ICONWARNING) != IDYES)
			return;
		KillTimer(NULL, iTimer);
		bActive = 0;
		g_pElv->Update();
	}

	/* The timer procedure animates an ellipsis in the status bar
	 * while the thread is running. */

	static auto proc = [](HWND, UINT, UINT_PTR, DWORD) -> void {
		static int i = 0;

		if (Pl("episode_data","thread_running",aThread)) {
			i = (i+1)%4;
			SendMessage(g_hWndStatus, SB_SETTEXT, MAKEWPARAM(1,0),
			    (LPARAM)(i==0? L".": i==1? L"..": i==2? L"...": L""));
		} else {
			KillTimer(NULL, iTimer);
			i = 0;
			bActive = 0;
			g_pElv->Update();
		}
	};

	Plx(szMod,"thread_create",szPred,&aThread);
	SendMessage(g_hWndStatus, SB_SETTEXT, MAKEWPARAM(1,0), (LPARAM)L".");
	if (prefer(iTimer = SetTimer(NULL, -1, 500, proc))) {
		wsPred = WsFromSz(szPred);
		bActive = 1;
	}
}

/* Handle messages to Help > About dialog. */
INT_PTR CALLBACK AboutDlgProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam, const LPARAM)
{
	switch (uMsg) {
	case WM_CLOSE:
		EndDialog(hWnd, IDOK);
		break;
	case WM_COMMAND:
		switch (LOWORD(wParam)) {
		case IDOK:
			EndDialog(hWnd, IDOK);
			break;
		}
		break;
	default:
		return FALSE;
	}

	return TRUE;
}

void UpdateLayout(int w, int h)
{
	if (!g_hWndStatus) return;

	RECT rc, rrStatus;
	if (w && h) rc = {0, 0, w, h};
	else require(GetClientRect(g_hWnd, &rc));
	require(GetRelativeRect(g_hWndStatus, &rrStatus));

	SendMessage(g_hWnd, WM_SETREDRAW, FALSE, 0);

	/* Resize list views. */
	const long pad = IsThemeActive()? Dpi(6): 0; /* Add padding in modern themes. */
	const long cyDlv = rrStatus.top-g_pDlv->Height()-pad;
	require(SetWindowRect(g_pDlv->hWnd, pad, cyDlv, rc.right-pad, rrStatus.top-pad));
	require(SetWindowRect(g_pElv->hWnd, pad, pad, rc.right-pad, cyDlv-pad));
	g_pDlv->ResizeColumns(rc.right-pad-pad);
	g_pElv->ResizeColumns(rc.right-pad-pad);

	/* Resize status bar parts. */
	const int aParts[] = {rc.right-Dpi(55), rc.right};
	SendMessage(g_hWndStatus, SB_SETPARTS, (WPARAM)sizeof(aParts), (LPARAM)aParts);

	SendMessage(g_hWnd, WM_SETREDRAW, TRUE, 0);
	RedrawWindow(g_hWnd, NULL, NULL,
	    RDW_ERASE|RDW_FRAME|RDW_INVALIDATE|RDW_ALLCHILDREN);
}

/* Try to style application according to current Windows theme. */
void UpdateTheme()
{
	if (!g_bThemes) return;
	const BOOL bThemeActive = IsThemeActive();
	g_pDlv->UpdateTheme(bThemeActive);
	g_pElv->UpdateTheme(bThemeActive);
}