import std.experimental.logger;
import std.range;
import std.string;
import std.stdio;
import std.typecons;

import vibe.d;

import article;
import page;
import project;
import watcher;

/**
 * Internal list of articles, pages and projects by slug.
 */
Article[string] articles;
Page[string] pages;
Project[string] projects;

/**
 * Default ordering and list with pointers to ordered articles.
 * (Note: this is code which will actually be compiled and passed on!)
 */
immutable string articleSortPred = "a.firstPublished > b.firstPublished";
Article*[] articleList;

immutable string pageSortPred = "a.title < b.title";
Page*[] pageList;

immutable string projectSortPred = "a.title < b.title";
Project*[] projectList;

/**
 * Output types for the content.
 */
enum OutputType {
	HTML,
	MARKDOWN
}

immutable string MIME_MARKDOWN = "text/markdown";

immutable Duration CACHE_TIME = days(16);

/**
 * Get's the document type for the given slug based on extension
 * and returns the slug without extension and the document type. Also removes the extension from the
 * slug.
 */
private OutputType getOutputType(ref string slug) {
	if (slug.endsWith(".md")) {
		slug = chomp(slug, ".md");
		return OutputType.MARKDOWN;
	} else if (slug.endsWith(".html")){
		// If explicitly asking for HTML, we'll return HTML
		slug = chomp(slug, ".html");
		return OutputType.HTML;
	} else {
		// If in the future, for any reason, we no longer use HTML
		// this allows to us to keep the current urls with an option
		// to change the output in the future.
		return OutputType.HTML;
	}
}

void addCachingHeader(bool publicCache = true)(ref HTTPServerResponse res) {
	string header = "";
	static if (publicCache) {
		header ~= "public";
	} else {
		header ~= "private";
	}
	header ~= ", max-age=" ~ to!string(CACHE_TIME.total!"seconds");
	res.headers["Cache-Control"] = header;
}

/**
 * Template method for fetching a single page for a subclass of page.
 * Params:
 *     T = the data structure/class to be passed as template parameter. Must have a slug parameter.
 *     templ = The template to use when rendering.
 *     array = An associative array where the keys are slugs for parameters and the values the template parameter.
 *     req = The server request to consume. Assumes there is an slug parameter.
 *     res = The server response to write to.
 *             
 */
void getSingle(T, string templ)(ref T[string] array, HTTPServerRequest req, HTTPServerResponse res) {
	string slug = req.params["slug"];
	OutputType outputType = getOutputType(slug);

	enforceHTTP(slug in array, HTTPStatus.notFound, "Page not found");
	T content = array[slug];
	switch(outputType) with (OutputType) {
	case MARKDOWN:
		res.writeBody(content.contentSource, MIME_MARKDOWN);
		break;
	default:
	case HTML:
		res.render!(templ, content);
		break;
	}
}

/**
 * Generates response for /posts/:slug and /palen/:slug.
 */
void articleGetSingle(HTTPServerRequest req, HTTPServerResponse res) {
	getSingle!(Article, "pages/article.dt")(articles, req, res);
}

/**
 * Generates response for /posts and /palen
 */
void articleGetOverview(HTTPServerRequest req, HTTPServerResponse res) {
	addCachingHeader(res);
	render!("pages/article-list.dt", articleList)(res);
}

/**
 * Generates response for /projects and /projecten
 */
void projectGetOverview(HTTPServerRequest req, HTTPServerResponse res) {
	addCachingHeader(res);
	render!("pages/project-list.dt", projectList)(res);
}

/**
 * Generate response for a page
 */
void pageGet(HTTPServerRequest req, HTTPServerResponse res) {
	addCachingHeader(res);
	// If no slug is supplied, it will be adjusted to "index"
	if (("slug" in req.params) is null)  {
		req.params.addField("slug", "index");
	}
	getSingle!(Page, "pages/page.dt")(pages, req, res);
}

/**
 * Generate response for a project page
 */
void projectGet(HTTPServerRequest req, HTTPServerResponse res) {
	res.headers["Cache-Control"] = "public";
	getSingle!(Project, "pages/project.dt")(projects, req, res);
}

/**
 * Generates response whenever an error occurs.
 */
@safe
void errorPage(HTTPServerRequest req, HTTPServerResponse res, HTTPServerErrorInfo error) {
	render!("pages/error.dt", error)(res);
}

void main() {
	HTTPServerSettings settings = new HTTPServerSettings;
	settings.bindAddresses = ["0.0.0.0"];
	settings.port = 3465;
	settings.serverString = "zeg ik lekker niet";
	settings.errorPageHandler = toDelegate(&errorPage);
	settings.keepAliveTimeout = dur!"seconds"(60);
	debug {
		settings.accessLogToConsole = true;
	}
	HTTPFileServerSettings fSettings = new HTTPFileServerSettings;
	fSettings.maxAge = days(16);
	
	URLRouter router = new URLRouter;
	router.get("/posts/:slug", &articleGetSingle);
	router.get("/palen/:slug", &articleGetSingle);
	router.get("/posts/", &articleGetOverview);
	router.get("/palen/", &articleGetOverview);
	router.get("/projects/", &projectGetOverview);
	router.get("/projects/:slug", &projectGet);
	router.get("/projecten/:slug", &projectGet);
	router.get("/static/*", serveStaticFiles("./public/", fSettings));
	router.get("/:slug", &pageGet);
	router.get("/", &pageGet);
	
	listenHTTP(settings, router);

	// Start indexing pages.
	runTask({
		initPages!(Page, pageSortPred)(pages, pageList, "pages");
	});
	runTask({
		initPages!(Article, articleSortPred)(articles, articleList, "articles");
	});
	runTask({
		initPages!(Project, projectSortPred)(projects, projectList, "projects");
	});
	runApplication();
}