/* Copyright (c) 2013-2015 Jeffrey Pfau
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "file-select.h"

#include "util/gui/font.h"
#include "util/vfs.h"

#include <stdlib.h>

DEFINE_VECTOR(FileList, char*);

#define ITERATION_SIZE 5
#define SCANNING_THRESHOLD 15

static void _cleanFiles(struct FileList* currentFiles) {
	size_t size = FileListSize(currentFiles);
	size_t i;
	for (i = 1; i < size; ++i) {
		free(*FileListGetPointer(currentFiles, i));
	}
	FileListClear(currentFiles);
}

static void _upDirectory(char* currentPath) {
	char* end = strrchr(currentPath, '/');
	if (!end) {
		return;
	}
	if (end == currentPath) {
		end[1] = '\0';
		return;
	}
	end[0] = '\0';
	if (end[1]) {
		return;
	}
	// TODO: What if there was a trailing slash?
}

static int _strpcmp(const void* a, const void* b) {
	return strcmp(*(const char**) a, *(const char**) b);
}

static bool _refreshDirectory(struct GUIParams* params, const char* currentPath, struct FileList* currentFiles, bool (*filter)(struct VFile*)) {
	_cleanFiles(currentFiles);

	struct VDir* dir = VDirOpen(currentPath);
	if (!dir) {
		return false;
	}
	*FileListAppend(currentFiles) = "(Up)";
	size_t i = 0;
	struct VDirEntry* de;
	while ((de = dir->listNext(dir))) {
		++i;
		if (i % SCANNING_THRESHOLD == SCANNING_THRESHOLD - 1) {
			int input = 0;
			GUIPollInput(params, &input, 0);
			if (input & (1 << GUI_INPUT_CANCEL)) {
				return false;
			}
			params->drawStart();
			GUIFontPrintf(params->font, 0, GUIFontHeight(params->font), GUI_TEXT_LEFT, 0xFFFFFFFF, "%s", currentPath);
			GUIFontPrintf(params->font, 0, GUIFontHeight(params->font) * 2, GUI_TEXT_LEFT, 0xFFFFFFFF, "(scanning)");
			params->drawEnd();
		}
		const char* name = de->name(de);
		if (name[0] == '.') {
			continue;
		}
		if (de->type(de) == VFS_FILE) {
			struct VFile* vf = dir->openFile(dir, name, O_RDONLY);
			if (!vf) {
				continue;
			}
			if (!filter || filter(vf)) {
				*FileListAppend(currentFiles) = strdup(name);
			}
			vf->close(vf);
		} else {
			*FileListAppend(currentFiles) = strdup(name);
		}
	}
	dir->close(dir);
	qsort(FileListGetPointer(currentFiles, 1), FileListSize(currentFiles) - 1, sizeof(char*), _strpcmp);
	return true;
}

bool GUISelectFile(struct GUIParams* params, char* outPath, size_t outLen, bool (*filter)(struct VFile*)) {
	size_t start = 0;
	size_t pageSize = params->height / GUIFontHeight(params->font);
	if (pageSize > 4) {
		pageSize -= 4;
	} else {
		pageSize = 1;
	}

	GUIInvalidateKeys(params);
	struct FileList currentFiles;
	FileListInit(&currentFiles, 0);
	_refreshDirectory(params, params->currentPath, &currentFiles, filter);

	while (true) {
		int newInput = 0;
		GUIPollInput(params, &newInput, 0);

		if (newInput & (1 << GUI_INPUT_UP) && params->fileIndex > 0) {
			--params->fileIndex;
		}
		if (newInput & (1 << GUI_INPUT_DOWN) && params->fileIndex < FileListSize(&currentFiles) - 1) {
			++params->fileIndex;
		}
		if (newInput & (1 << GUI_INPUT_LEFT)) {
			if (params->fileIndex >= pageSize) {
				params->fileIndex -= pageSize;
			} else {
				params->fileIndex = 0;
			}
		}
		if (newInput & (1 << GUI_INPUT_RIGHT)) {
			if (params->fileIndex + pageSize < FileListSize(&currentFiles)) {
				params->fileIndex += pageSize;
			} else {
				params->fileIndex = FileListSize(&currentFiles) - 1;
			}
		}

		if (params->fileIndex < start) {
			start = params->fileIndex;
		}
		while ((params->fileIndex - start + 4) * GUIFontHeight(params->font) > params->height) {
			++start;
		}
		if (newInput & (1 << GUI_INPUT_CANCEL)) {
			break;
		}
		if (newInput & (1 << GUI_INPUT_SELECT)) {
			if (params->fileIndex == 0) {
				_upDirectory(params->currentPath);
				if (!_refreshDirectory(params, params->currentPath, &currentFiles, filter)) {
					break;
				}
			} else {
				size_t len = strlen(params->currentPath);
				const char* sep = PATH_SEP;
				if (params->currentPath[len - 1] == *sep) {
					sep = "";
				}
				snprintf(outPath, outLen, "%s%s%s", params->currentPath, sep, *FileListGetPointer(&currentFiles, params->fileIndex));

				struct FileList newFiles;
				FileListInit(&newFiles, 0);
				if (!_refreshDirectory(params, outPath, &newFiles, filter)) {
					_cleanFiles(&newFiles);
					FileListDeinit(&newFiles);
					struct VFile* vf = VFileOpen(outPath, O_RDONLY);
					if (!vf) {
						continue;
					}
					if (!filter || filter(vf)) {
						vf->close(vf);
						_cleanFiles(&currentFiles);
						FileListDeinit(&currentFiles);
						return true;
					}
					vf->close(vf);
					break;
				} else {
					_cleanFiles(&currentFiles);
					FileListDeinit(&currentFiles);
					currentFiles = newFiles;
					strncpy(params->currentPath, outPath, PATH_MAX);
				}
			}
			params->fileIndex = 0;
		}
		if (newInput & (1 << GUI_INPUT_BACK)) {
			if (strncmp(params->currentPath, params->basePath, PATH_MAX) == 0) {
				break;
			}
			_upDirectory(params->currentPath);
			if (!_refreshDirectory(params, params->currentPath, &currentFiles, filter)) {
				break;
			}
			params->fileIndex = 0;
		}

		params->drawStart();
		unsigned y = GUIFontHeight(params->font);
		GUIFontPrintf(params->font, 0, y, GUI_TEXT_LEFT, 0xFFFFFFFF, "%s", params->currentPath);
		y += 2 * GUIFontHeight(params->font);
		size_t i;
		for (i = start; i < FileListSize(&currentFiles); ++i) {
			int color = 0xE0A0A0A0;
			char bullet = ' ';
			if (i == params->fileIndex) {
				color = 0xFFFFFFFF;
				bullet = '>';
			}
			GUIFontPrintf(params->font, 0, y, GUI_TEXT_LEFT, color, "%c %s", bullet, *FileListGetPointer(&currentFiles, i));
			y += GUIFontHeight(params->font);
			if (y + GUIFontHeight(params->font) > params->height) {
				break;
			}
		}
		y += GUIFontHeight(params->font) * 2;

		params->drawEnd();
	}

	_cleanFiles(&currentFiles);
	FileListDeinit(&currentFiles);
	return false;
}