/* jslint node: true */
'use strict';

const Config			= require('./config.js').config;
const art				= require('./art.js');
const ansi				= require('./ansi_term.js');
const Log				= require('./logger.js').log;
const ConfigCache		= require('./config_cache.js');
const getFullConfig		= require('./config_util.js').getFullConfig;
const asset				= require('./asset.js');
const ViewController	= require('./view_controller.js').ViewController;
const Errors			= require('./enig_error.js').Errors;
const ErrorReasons		= require('./enig_error.js').ErrorReasons;
const Events			= require('./events.js');

const fs				= require('graceful-fs');
const paths				= require('path');
const async				= require('async');
const _					= require('lodash');
const assert			= require('assert');

exports.getThemeArt				= getThemeArt;
exports.getAvailableThemes		= getAvailableThemes;
exports.getRandomTheme			= getRandomTheme;
exports.setClientTheme          = setClientTheme;
exports.initAvailableThemes		= initAvailableThemes;
exports.displayThemeArt			= displayThemeArt;
exports.displayThemedPause		= displayThemedPause;
exports.displayThemedPrompt		= displayThemedPrompt;
exports.displayThemedAsset		= displayThemedAsset;

function refreshThemeHelpers(theme) {
	//
	//	Create some handy helpers
	//
	theme.helpers = {
		getPasswordChar : function() {
			let pwChar = _.get(
				theme,
				'customization.defaults.general.passwordChar',
				Config.defaults.passwordChar
			);

			if(_.isString(pwChar)) {
				pwChar = pwChar.substr(0, 1);
			} else if(_.isNumber(pwChar)) {
				pwChar = String.fromCharCode(pwChar);
			}

			return pwChar;
		},
		getDateFormat : function(style = 'short') {
			const format = Config.defaults.dateFormat[style] || 'MM/DD/YYYY';
			return _.get(theme, `customization.defaults.dateFormat.${style}`, format);
		},
		getTimeFormat : function(style = 'short') {
			const format = Config.defaults.timeFormat[style] || 'h:mm a';
			return _.get(theme, `customization.defaults.timeFormat.${style}`, format);
		},
		getDateTimeFormat : function(style = 'short') {
			const format = Config.defaults.dateTimeFormat[style] || 'MM/DD/YYYY h:mm a';
			return _.get(theme, `customization.defaults.dateTimeFormat.${style}`, format);
		}
	};
}

function loadTheme(themeId, cb) {
	const path = paths.join(Config.paths.themes, themeId, 'theme.hjson');

	const changed = ( { fileName, fileRoot } ) => {
		const reCachedPath = paths.join(fileRoot, fileName);
		if(reCachedPath === path) {
			reloadTheme(themeId);
		}
	};

	const getOpts = {
		filePath 		: path,
		forceReCache	: true,
		callback		: changed,
	};

	ConfigCache.getConfigWithOptions(getOpts, (err, theme) => {
		if(err) {
			return cb(err);
		}

		if(!_.isObject(theme.info) ||
			!_.isString(theme.info.name) ||
			!_.isString(theme.info.author))
		{
			return cb(Errors.Invalid('Invalid or missing "info" section'));
		}

		if(false === _.get(theme, 'info.enabled')) {
			return cb(Errors.General('Theme is not enalbed', ErrorReasons.ErrNotEnabled));
		}

		refreshThemeHelpers(theme);

		return cb(null, theme, path);
	});
}

const availableThemes = new Map();

const IMMUTABLE_MCI_PROPERTIES = [
	'maxLength', 'argName', 'submit', 'validate'
];

function getMergedTheme(menuConfig, promptConfig, theme) {
	assert(_.isObject(menuConfig));
	assert(_.isObject(theme));

	//  :TODO: merge in defaults (customization.defaults{} )
	//	:TODO: apply generic stuff, e.g. "VM" (vs "VM1")

	//
	//  Create a *clone* of menuConfig (menu.hjson) then bring in
	//  promptConfig (prompt.hjson)
	//
	const mergedTheme = _.cloneDeep(menuConfig);

	if(_.isObject(promptConfig.prompts)) {
		mergedTheme.prompts = _.cloneDeep(promptConfig.prompts);
	}

	//
	//  Add in data we won't be altering directly from the theme
	//
	mergedTheme.info    = theme.info;
	mergedTheme.helpers = theme.helpers;

	//
	//  merge customizer to disallow immutable MCI properties
	//
	const mciCustomizer = function(objVal, srcVal, key) {
		return IMMUTABLE_MCI_PROPERTIES.indexOf(key) > -1 ? objVal : srcVal;
	};

	function getFormKeys(fromObj) {
		return _.remove(_.keys(fromObj), function pred(k) {
			return !isNaN(k);    //  remove all non-numbers
		});
	}

	function mergeMciProperties(dest, src) {
		Object.keys(src).forEach(function mciEntry(mci) {
			_.mergeWith(dest[mci], src[mci], mciCustomizer);
		});
	}

	function applyThemeMciBlock(dest, src, formKey) {
		if(_.isObject(src.mci)) {
			mergeMciProperties(dest, src.mci);
		} else {
			if(_.has(src, [ formKey, 'mci' ])) {
				mergeMciProperties(dest, src[formKey].mci);
			}
		}
	}

	//
	//  menu.hjson can have a couple different structures:
	//  1)  Explicit declaration of expected MCI code(s) under 'form:<id>' before a 'mci' block
	//      (this allows multiple layout types defined by one menu for example)
	//
	//  2)  Non-explicit declaration: 'mci' directly under 'form:<id>'
	//
	//  theme.hjson has it's own mix:
	//  1)  Explicit: Form ID before 'mci' (generally used where there are > 1 forms)
	//
	//  2)  Non-explicit: 'mci' directly under an entry
	//
	//  Additionally, #1 or #2 may be under an explicit key of MCI code(s) to match up
	//  with menu.hjson in #1.
	//
	//  *   When theming an explicit menu.hjson entry (1), we will use a matching explicit
	//      entry with a matching MCI code(s) key in theme.hjson (e.g. menu="ETVM"/theme="ETVM"
	//      and fall back to generic if a match is not found.
	//
	//  *   If theme.hjson provides form ID's, use them. Otherwise, we'll apply directly assuming
	//      there is a generic 'mci' block.
	//
	function applyToForm(form, menuTheme, formKey) {
		if(_.isObject(form.mci)) {
			//   non-explicit: no MCI code(s) key assumed since we found 'mci' directly under form ID
			applyThemeMciBlock(form.mci, menuTheme, formKey);

		} else {
			const menuMciCodeKeys = _.remove(_.keys(form), function pred(k) {
				return k === k.toUpperCase(); //  remove anything not uppercase
			});

			menuMciCodeKeys.forEach(function mciKeyEntry(mciKey) {
				let applyFrom;
				if(_.has(menuTheme, [ mciKey, 'mci' ])) {
					applyFrom = menuTheme[mciKey];
				} else {
					applyFrom = menuTheme;
				}

				applyThemeMciBlock(form[mciKey].mci, applyFrom, formKey);
			});
		}
	}

	[ 'menus', 'prompts' ].forEach(function areaEntry(sectionName) {
		_.keys(mergedTheme[sectionName]).forEach(function menuEntry(menuName) {
			let createdFormSection = false;
			const mergedThemeMenu = mergedTheme[sectionName][menuName];

			if(_.has(theme, [ 'customization', sectionName, menuName ])) {
				const menuTheme = theme.customization[sectionName][menuName];

				//	config block is direct assign/overwrite
				//  :TODO: should probably be _.merge()
				if(menuTheme.config) {
					mergedThemeMenu.config = _.assign(mergedThemeMenu.config || {}, menuTheme.config);
				}

				if('menus' === sectionName) {
					if(_.isObject(mergedThemeMenu.form)) {
						getFormKeys(mergedThemeMenu.form).forEach(function formKeyEntry(formKey) {
							applyToForm(mergedThemeMenu.form[formKey], menuTheme, formKey);
						});
					} else {
						if(_.isObject(menuTheme.mci)) {
							//
							//  Not specified at menu level means we apply anything from the
							//  theme to form.0.mci{}
							//
							mergedThemeMenu.form = { 0 : { mci : { } } };
							mergeMciProperties(mergedThemeMenu.form[0], menuTheme);
							createdFormSection = true;
						}
					}
				} else if('prompts' === sectionName) {
					//  no 'form' or form keys for prompts -- direct to mci
					applyToForm(mergedThemeMenu, menuTheme);
				}
			}

			//
			//  Finished merging for this menu/prompt
			//
			//  If the following conditions are true, set runtime.autoNext to true:
			//  *   This is a menu
			//  *   There is/was no explicit 'form' section
			//  *   There is no 'prompt' specified
			//
			if('menus' === sectionName && !_.isString(mergedThemeMenu.prompt) &&
				(createdFormSection || !_.isObject(mergedThemeMenu.form)))
			{
				mergedThemeMenu.runtime = _.merge(mergedThemeMenu.runtime || {}, { autoNext : true } );
			}
		});
	});


	return mergedTheme;
}

function reloadTheme(themeId) {
	async.waterfall(
		[
			function loadMenuConfig(callback) {
				getFullConfig(Config.general.menuFile, (err, menuConfig) => {
					return callback(err, menuConfig);
				});
			},
			function loadPromptConfig(menuConfig, callback) {
				getFullConfig(Config.general.promptFile, (err, promptConfig) => {
					return callback(err, menuConfig, promptConfig);
				});
			},
			function loadIt(menuConfig, promptConfig, callback) {
				loadTheme(themeId, (err, theme) => {
					if(err) {
						if(ErrorReasons.NotEnabled !== err.reasonCode) {
							Log.warn( { themeId : themeId, err : err.message }, 'Failed loading theme');
							return;
						}
						return callback(err);
					}

					Object.assign(theme.info, { themeId } );
					availableThemes.set(themeId, getMergedTheme(menuConfig, promptConfig, theme));

					Events.emit(
						Events.getSystemEvents().ThemeChanged,
						{ themeId }
					);

					return callback(null, theme);
				});
			}
		],
		(err, theme) => {
			if(err) {
				Log.warn( { themeId, error : err.message }, 'Failed to reload theme');
			} else {
				Log.debug( { info : theme.info }, 'Theme recached' );
			}
		}
	);
}

function reloadAllThemes()
{
	async.each([ ...availableThemes.keys() ], themeId => reloadTheme(themeId));
}

function initAvailableThemes(cb) {

	async.waterfall(
		[
			function loadMenuConfig(callback) {
				getFullConfig(Config.general.menuFile, (err, menuConfig) => {
					return callback(err, menuConfig);
				});
			},
			function loadPromptConfig(menuConfig, callback) {
				getFullConfig(Config.general.promptFile, (err, promptConfig) => {
					return callback(err, menuConfig, promptConfig);
				});
			},
			function getThemeDirectories(menuConfig, promptConfig, callback) {
				fs.readdir(Config.paths.themes, (err, files) =>  {
					if(err) {
						return callback(err);
					}

					return callback(
						null,
						menuConfig,
						promptConfig,
						files.filter( f => {
							//	sync normally not allowed -- initAvailableThemes() is a startup-only method, however
							return fs.statSync(paths.join(Config.paths.themes, f)).isDirectory();
						})
					);
				});
			},
			function populateAvailable(menuConfig, promptConfig, themeDirectories, callback) {
				async.each(themeDirectories, (themeId, nextThemeDir) => {	//	theme dir = theme ID
					loadTheme(themeId, (err, theme) => {
						if(err) {
							if(ErrorReasons.NotEnabled !== err.reasonCode) {
								Log.warn( { themeId : themeId, err : err.message }, 'Failed loading theme');
							}

							return nextThemeDir(null);	//	try next
						}

						Object.assign(theme.info, { themeId } );
						availableThemes.set(themeId, getMergedTheme(menuConfig, promptConfig, theme));
						return nextThemeDir(null);
					});
				}, err => {
					return callback(err);
				});
			},
			function initEvents(callback) {
				Events.on(Events.getSystemEvents().MenusChanged, () => {
					return reloadAllThemes();
				});
				Events.on(Events.getSystemEvents().PromptsChanged, () => {
					return reloadAllThemes();
				});

				return callback(null);
			}
		],
		err => {
			return cb(err, availableThemes.size);
		}
	);
}

function getAvailableThemes() {
	return availableThemes;
}

function getRandomTheme() {
	if(availableThemes.size > 0) {
		const themeIds = [ ...availableThemes.keys() ];
		return themeIds[Math.floor(Math.random() * themeIds.length)];
	}
}

function setClientTheme(client, themeId) {
	const availThemes = getAvailableThemes();

	let msg;
	let setThemeId;
	if(availThemes.has(themeId)) {
		msg = 'Set client theme';
		setThemeId = themeId;
	} else if(availThemes.has(Config.defaults.theme)) {
		msg = 'Failed setting theme by supplied ID; Using default';
		setThemeId = Config.defaults.theme;
	} else {
		msg = 'Failed setting theme by system default ID; Using the first one we can find';
		setThemeId = availThemes.keys().next().value;
	}

	client.currentTheme = availThemes.get(setThemeId);
	client.log.debug( { setThemeId, requestedThemeId : themeId, info : client.currentTheme.info }, msg);
}

function getThemeArt(options, cb) {
	//
	//	options - required:
	//		name
	//
	//	options - optional
	//		client - needed for user's theme/etc.
	//		themeId
	//		asAnsi
	//		readSauce
	//		random
	//
	if(!options.themeId && _.has(options, 'client.user.properties.theme_id')) {
		options.themeId = options.client.user.properties.theme_id;
	} else {
		options.themeId = Config.defaults.theme;
	}

	//	:TODO: replace asAnsi stuff with something like retrieveAs = 'ansi' | 'pipe' | ...
	//	:TODO: Some of these options should only be set if not provided!
	options.asAnsi		= true;	//	always convert to ANSI
	options.readSauce	= true;	//	read SAUCE, if avail
	options.random		= _.get(options, 'random', true);	//	FILENAME<n>.EXT support

	//
	//	We look for themed art in the following order:
	//	1)	Direct/relative path
	//	2)	Via theme supplied by |themeId|
	//	3)	Via default theme
	//	4)	General art directory
	//
	async.waterfall(
		[
			function fromPath(callback) {
				//
				//	We allow relative (to enigma-bbs) or full paths
				//
				if('/' === options.name.charAt(0)) {
					//	just take the path as-is
					options.basePath = paths.dirname(options.name);
				} else if(options.name.indexOf('/') > -1) {
					//	make relative to base BBS dir
					options.basePath = paths.join(__dirname, '../', paths.dirname(options.name));
				} else {
					return callback(null, null);
				}

				art.getArt(options.name, options, (err, artInfo) => {
					return callback(null, artInfo);
				});
			},
			function fromSuppliedTheme(artInfo, callback) {
				if(artInfo) {
					return callback(null, artInfo);
				}

				options.basePath = paths.join(Config.paths.themes, options.themeId);
				art.getArt(options.name, options, (err, artInfo) => {
					return callback(null, artInfo);
				});
			},
			function fromDefaultTheme(artInfo, callback) {
				if(artInfo || Config.defaults.theme === options.themeId) {
					return callback(null, artInfo);
				}

				options.basePath = paths.join(Config.paths.themes, Config.defaults.theme);
				art.getArt(options.name, options, (err, artInfo) => {
					return callback(null, artInfo);
				});
			},
			function fromGeneralArtDir(artInfo, callback) {
				if(artInfo) {
					return callback(null, artInfo);
				}

				options.basePath = Config.paths.art;
				art.getArt(options.name, options, (err, artInfo) => {
					return callback(err, artInfo);
				});
			}
		],
		function complete(err, artInfo) {
			if(err) {
				const logger = _.get(options, 'client.log') || Log;
				logger.debug( { reason : err.message }, 'Cannot find theme art');
			}
			return cb(err, artInfo);
		}
	);
}

function displayThemeArt(options, cb) {
	assert(_.isObject(options));
	assert(_.isObject(options.client));
	assert(_.isString(options.name));

	getThemeArt(options, (err, artInfo) => {
		if(err) {
			return cb(err);
		}
		//	:TODO: just use simple merge of options -> displayOptions
		const displayOpts = {
			sauce		: artInfo.sauce,
			font		: options.font,
			trailingLF	: options.trailingLF,
		};

		art.display(options.client, artInfo.data, displayOpts, (err, mciMap, extraInfo) => {
			return cb(err, { mciMap : mciMap, artInfo : artInfo, extraInfo : extraInfo } );
		});
	});
}

function displayThemedPrompt(name, client, options, cb) {

	const useTempViewController = _.isUndefined(options.viewController);

	async.waterfall(
		[
			function display(callback) {
				const promptConfig = client.currentTheme.prompts[name];
				if(!promptConfig) {
					return callback(Errors.DoesNotExist(`Missing "${name}" prompt configuration!`));
				}

				if(options.clearScreen) {
					client.term.rawWrite(ansi.resetScreen());
				}

				//
				//	If we did *not* clear the screen, don't let the font change
				//	doing so messes things up -- most terminals that support font
				//	changing can only display a single font at at time.
				//
				//	:TODO: We can use term detection to do nifty things like avoid this kind of kludge:
				const dispOptions = Object.assign( {}, promptConfig.options );
				if(!options.clearScreen) {
					dispOptions.font = 'not_really_a_font!';	//	kludge :)
				}

				displayThemedAsset(
					promptConfig.art,
					client,
					dispOptions,
					(err, artInfo) => {
						if(err) {
							return callback(err);
						}

						return callback(null, promptConfig, artInfo);
					}
				);
			},
			function discoverCursorPosition(promptConfig, artInfo, callback) {
				if(!options.clearPrompt) {
					//	no need to query cursor - we're not gonna use it
					return callback(null, promptConfig, artInfo);
				}

				client.once('cursor position report', pos => {
					artInfo.startRow = pos[0] - artInfo.height;
					return callback(null, promptConfig, artInfo);
				});

				client.term.rawWrite(ansi.queryPos());
			},
			function createMCIViews(promptConfig, artInfo, callback) {
				const tempViewController = useTempViewController ? new ViewController( { client : client } ) : options.viewController;

				const loadOpts = {
					promptName	: name,
					mciMap		: artInfo.mciMap,
					config		: promptConfig,
				};

				tempViewController.loadFromPromptConfig(loadOpts, () => {
					return callback(null, artInfo, tempViewController);
				});
			},
			function pauseForUserInput(artInfo, tempViewController, callback) {
				if(!options.pause) {
					return callback(null, artInfo, tempViewController);
				}

				client.waitForKeyPress( () => {
					return callback(null, artInfo, tempViewController);
				});
			},
			function clearPauseArt(artInfo, tempViewController, callback) {
				if(options.clearPrompt) {
					if(artInfo.startRow && artInfo.height) {
						client.term.rawWrite(ansi.goto(artInfo.startRow, 1));

						//	Note: Does not work properly in NetRunner < 2.0b17:
						client.term.rawWrite(ansi.deleteLine(artInfo.height));
					} else {
						client.term.rawWrite(ansi.eraseLine(1));
					}
				}

				return callback(null, tempViewController);
			}
		],
		(err, tempViewController) => {
			if(err) {
				client.log.warn( { error : err.message }, `Failed displaying "${name}" prompt` );
			}

			if(tempViewController && useTempViewController) {
				tempViewController.detachClientEvents();
			}

			return cb(null);
		}
	);
}

//
//	Pause prompts are a special prompt by the name 'pause'.
//
function displayThemedPause(client, options, cb) {

	if(!cb && _.isFunction(options)) {
		cb = options;
		options = {};
	}

	if(!_.isBoolean(options.clearPrompt)) {
		options.clearPrompt = true;
	}

	const promptOptions = Object.assign( {}, options, { pause : true } );
	return displayThemedPrompt('pause', client, promptOptions, cb);
}

function displayThemedAsset(assetSpec, client, options, cb) {
	assert(_.isObject(client));

	//	options are... optional
	if(3 === arguments.length) {
		cb = options;
		options = {};
	}

	if(Array.isArray(assetSpec) && _.isString(options.acsCondMember)) {
		assetSpec = client.acs.getConditionalValue(assetSpec, options.acsCondMember);
	}

	const artAsset = asset.getArtAsset(assetSpec);
	if(!artAsset) {
		return cb(new Error('Asset not found: ' + assetSpec));
	}

	//	:TODO: just use simple merge of options -> displayOptions
	var dispOpts = {
		name			: artAsset.asset,
		client			: client,
		font			: options.font,
		trailingLF		: options.trailingLF,
	};

	switch(artAsset.type) {
		case 'art' :
			displayThemeArt(dispOpts, function displayed(err, artData) {
				return cb(err, err ? null : { mciMap : artData.mciMap, height : artData.extraInfo.height } );
			});
			break;

		case 'method' :
			//	:TODO: fetch & render via method
			break;

		case 'inline ' :
			//	:TODO: think about this more in relation to themes, etc. How can this come
			//	from a theme (with override from menu.json) ???
			//	look @ client.currentTheme.inlineArt[name] -> menu/prompt[name]
			break;

		default :
			return cb(new Error('Unsupported art asset type: ' + artAsset.type));
	}
}