/**
	Generates offline documentation in the form of HTML files.

	Copyright: © 2012 RejectedSoftware e.K.
	License: Subject to the terms of the MIT license, as written in the included LICENSE.txt file.
	Authors: Sönke Ludwig
*/
module ddox.htmlgenerator;

import ddox.api;
import ddox.entities;
import ddox.settings;

import std.algorithm : canFind, countUntil, map;
import std.array;
import std.digest.md;
import std.format : formattedWrite;
import std..string : startsWith, toLower;
import std.traits : EnumMembers;
import std.variant;
import vibe.core.log;
import vibe.core.file;
import vibe.core.stream;
import vibe.data.json;
import vibe.inet.path;
import vibe.http.server;
import vibe.stream.wrapper : streamOutputRange;
import diet.html;
import diet.traits : dietTraits;


/*
	structure:
	/index.html
	/pack1/pack2/module1.html
	/pack1/pack2/module1/member.html
	/pack1/pack2/module1/member.submember.html
*/

version (Windows) version = CaseInsensitiveFS;
else version (OSX) version = CaseInsensitiveFS;

void generateHtmlDocs(NativePath dst_path, Package root, GeneratorSettings settings = null)
{
	import std.algorithm : splitter;
	import vibe.web.common : adjustMethodStyle;

	if( !settings ) settings = new GeneratorSettings;

	version (CaseInsensitiveFS) {
		final switch (settings.fileNameStyle) with (MethodStyle) {
			case unaltered, camelCase, pascalCase:
				logWarn("On Windows and OS X, file names that differ only in their case "
					~ "are treated as equal by default. Use one of the "
					~ "lower/upper case styles with the --file-name-style "
					~ "option to avoid missing files in the generated output.");
				break;
			case lowerCase, upperCase, lowerUnderscored, upperUnderscored:
				break;
		}
	}

	string[string] file_hashes;
	string[string] new_file_hashes;

	const hash_file_name = dst_path ~ "file_hashes.json";
	if (existsFile(hash_file_name)) {
		auto hfi = getFileInfo(hash_file_name);
		auto hf = readFileUTF8(hash_file_name);
		file_hashes = deserializeJson!(string[string])(hf);
	}

	string linkTo(in Entity ent_, size_t level)
	{
		import std.typecons : Rebindable;

		auto dst = appender!string();
		Rebindable!(const(Entity)) ent = ent_;

		if( level ) foreach( i; 0 .. level ) dst.put("../");
		else dst.put("./");

		if( ent !is null ){
			if( !ent.parent ){
				dst.put("index.html");
				return dst.data();
			}

			Entity nested;
			if (
				// link parameters to their function
				(cast(FunctionDeclaration)ent.parent !is null &&
				 (nested = cast(VariableDeclaration)ent) !is null) ||
				// link enum members to their enum
				(!settings.enumMemberPages &&
				 cast(EnumDeclaration)ent.parent !is null &&
				 (nested = cast(EnumMemberDeclaration)ent) !is null))
				ent = ent.parent;

			const(Entity)[] nodes;
			size_t mod_idx = 0;
			while( ent ){
				if( cast(const(Module))ent ) mod_idx = nodes.length;
				nodes ~= ent.get;
				ent = ent.parent;
			}
			foreach_reverse(i, n; nodes[mod_idx .. $-1]){
				dst.put(n.name[]);
				if( i > 0 ) dst.put('/');
			}
			if( mod_idx == 0 ) dst.put(".html");
			else {
				dst.put('/');
				foreach_reverse(n; nodes[0 .. mod_idx]){
					dst.put(adjustMethodStyle(n.name, settings.fileNameStyle));
					dst.put('.');
				}
				dst.put("html");
			}

			// FIXME: conflicting ids with parameters occurring in multiple overloads
			// link nested elements to anchor in parent, e.g. params, enum members
			if( nested ){
				dst.put('#');
				dst.put(nested.name[]);
			}
		}

		return dst.data();
	}

	void collectChildren(Entity parent, ref DocGroup[][string] pages)
	{
		Declaration[] members;
		if (!settings.enumMemberPages && cast(EnumDeclaration)parent)
			return;

		if (auto mod = cast(Module)parent) members = mod.members;
		else if (auto ctd = cast(CompositeTypeDeclaration)parent) members = ctd.members;
		else if (auto td = cast(TemplateDeclaration)parent) members = td.members;

		foreach (decl; members) {
			if (decl.parent !is parent) continue; // exclude inherited members (issue #120)
			auto style = settings.fileNameStyle; // workaround for invalid value when directly used inside lamba
			auto name = decl.nestedName.splitter(".").map!(n => adjustMethodStyle(n, style)).join(".");
			auto pl = name in pages;
			if (pl && !canFind(*pl, decl.docGroup)) *pl ~= decl.docGroup;
			else if (!pl) pages[name] = [decl.docGroup];

			collectChildren(decl, pages);
		}
	}

	void writeHashedFile(NativePath filename, scope void delegate(OutputStream) del)
	{
		import std.range : drop, walkLength;
		import vibe.stream.memory;

		assert(filename.startsWith(dst_path));

		auto str = createMemoryOutputStream();
		del(str);
		auto h = md5Of(str.data).toHexString.idup;
		version (Have_vibe_core)
			auto relfilename = NativePath(filename.bySegment.drop(dst_path.bySegment.walkLength)).toString();
		else
			auto relfilename = NativePath(filename.bySegment.drop(dst_path.bySegment.walkLength), false).toString();
		auto ph = relfilename in file_hashes;
		if (!ph || *ph != h) {
			//logInfo("do write %s", filename);
			writeFile(filename, str.data);
		}
		new_file_hashes[relfilename] = h;
	}

	void visitModule(Module mod, NativePath pack_path)
	{
		import std.range : walkLength;

		auto modpath = pack_path ~ NativePath.Segment(mod.name);
		if (!existsFile(modpath)) createDirectory(modpath);
		logInfo("Generating module: %s", mod.qualifiedName);
		writeHashedFile(pack_path ~ NativePath.Segment(mod.name~".html"), (stream) {
			generateModulePage(stream, root, mod, settings, ent => linkTo(ent, pack_path.bySegment.walkLength-dst_path.bySegment.walkLength));
		});

		DocGroup[][string] pages;
		collectChildren(mod, pages);
		foreach (name, decls; pages)
			writeHashedFile(modpath ~ NativePath.Segment(name~".html"), (stream) {
				generateDeclPage(stream, root, mod, name, decls, settings, ent => linkTo(ent, modpath.bySegment.walkLength-dst_path.bySegment.walkLength));
			});
	}

	void visitPackage(Package p, NativePath path)
	{
		auto packpath = p.parent ? path ~ NativePath.Segment(p.name) : path;
		if( !packpath.empty && !existsFile(packpath) ) createDirectory(packpath);
		foreach( sp; p.packages ) visitPackage(sp, packpath);
		foreach( m; p.modules ) visitModule(m, packpath);
	}

	dst_path.normalize();

	if( !dst_path.empty && !existsFile(dst_path) ) createDirectory(dst_path);

	writeHashedFile(dst_path ~ NativePath.Segment("index.html"), (stream) {
		generateApiIndex(stream, root, settings, ent => linkTo(ent, 0));
	});

	writeHashedFile(dst_path ~ "symbols.js", (stream) {
		generateSymbolsJS(stream, root, settings, ent => linkTo(ent, 0));
	});

	writeHashedFile(dst_path ~ NativePath.Segment("sitemap.xml"), (stream) {
		generateSitemap(stream, root, settings, ent => linkTo(ent, 0));
	});

	visitPackage(root, dst_path);

	// delete obsolete files
	foreach (f; file_hashes.byKey)
		if (f !in new_file_hashes) {
			try removeFile(dst_path ~ NativePath(f));
			catch (Exception e) logWarn("Failed to remove obsolete file '%s': %s", f, e.msg);
		}

	// write new file hash list
	writeFileUTF8(hash_file_name, new_file_hashes.serializeToJsonString());
}

class DocPageInfo {
	string delegate(in Entity ent) linkTo;
	GeneratorSettings settings;
	Package rootPackage;
	Entity node;
	Module mod;
	DocGroup[] docGroups; // for multiple doc groups with the same name
	string nestedName;

	@property NavigationType navigationType() const { return settings.navigationType; }
	string formatType(CachedType tp, bool include_code_tags = true) { return .formatType(tp, linkTo, include_code_tags); }
	void renderTemplateArgs(R)(R output, Declaration decl) { .renderTemplateArgs(output, decl, linkTo); }
	string formatDoc(DocGroup group, int hlevel, bool delegate(string) display_section)
	{
		if (!group) return null;
		// TODO: memoize the DocGroupContext
		return group.comment.renderSections(new DocGroupContext(group, linkTo, settings), display_section, hlevel);
	}
}

@dietTraits
struct DdoxDietTraits(HTMLOutputStyle htmlStyle) {
	// fields and functions must be static atm., see https://github.com/rejectedsoftware/diet-ng/issues/33
	enum HTMLOutputStyle htmlOutputStyle = htmlStyle;
}

void generateSitemap(OutputStream)(OutputStream dst, Package root_package, GeneratorSettings settings, string delegate(in Entity) link_to, HTTPServerRequest req = null)
	if (isOutputStream!OutputStream)
{
	dst.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
	dst.write("<urlset xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\">\n");

	void writeEntry(string[] parts...){
		dst.write("<url><loc>");
		foreach( p; parts )
			dst.write(p);
		dst.write("</loc></url>\n");
	}

	void writeEntityRec(Entity ent){
		import std..string;
		if (!cast(Package)ent || ent is root_package) {
			auto link = link_to(ent);
			if (indexOf(link, '#') < 0) { // ignore URLs with anchors
				auto p = InetPath(link);
				p.normalize();
				writeEntry((settings.siteUrl ~ p).toString());
			}
		}
		ent.iterateChildren((ch){ writeEntityRec(ch); return true; });
	}

	writeEntityRec(root_package);

	dst.write("</urlset>\n");
	dst.flush();
}

void generateSymbolsJS(OutputStream)(OutputStream dst, Package root_package, GeneratorSettings settings, string delegate(in Entity) link_to)
	if (isOutputStream!OutputStream)
{
	import std.typecons : Tuple, tuple;

	bool[Tuple!(Entity, CachedString)] visited;

	auto rng = streamOutputRange(dst);

	void writeEntry(Entity ent) {
		auto key = tuple(ent.parent, ent.name);
		if (cast(Package)ent || cast(TemplateParameterDeclaration)ent) return;
		if (key in visited) return;
		visited[key] = true;

		string kind = ent.classinfo.name.split(".")[$-1].toLower;
		const(CachedString)[] cattributes;
		if (auto fdecl = cast(FunctionDeclaration)ent) cattributes = fdecl.attributes;
		else if (auto adecl = cast(AliasDeclaration)ent) cattributes = adecl.attributes;
		else if (auto tdecl = cast(TypedDeclaration)ent) cattributes = tdecl.type.attributes;
		auto attributes = cattributes.map!(a => a.str.startsWith("@") ? a[1 .. $] : a);
		(&rng).formattedWrite(`{name: '%s', kind: "%s", path: '%s', attributes: %s},`, ent.qualifiedName, kind, link_to(ent), attributes);
		rng.put('\n');
	}

	void writeEntryRec(Entity ent) {
		writeEntry(ent);
		if (cast(FunctionDeclaration)ent) return;
		ent.iterateChildren((ch) { writeEntryRec(ch); return true; });
	}

	rng.put("// symbol index generated by DDOX - do not edit\n");
	rng.put("var symbols = [\n");
	writeEntryRec(root_package);
	rng.put("];\n");
}

void generateApiIndex(OutputStream)(OutputStream dst, Package root_package, GeneratorSettings settings, string delegate(in Entity) link_to, HTTPServerRequest req = null)
	if (isOutputStream!OutputStream)
{
	auto info = new DocPageInfo;
	info.linkTo = link_to;
	info.settings = settings;
	info.rootPackage = root_package;
	info.node = root_package;

	auto rng = streamOutputRange(dst);
	final switch (settings.htmlOutputStyle)
	{
		foreach (htmlOutputStyle; EnumMembers!HTMLOutputStyle)
		case htmlOutputStyle:
		{
			rng.compileHTMLDietFile!("ddox.overview.dt", req, info, DdoxDietTraits!(htmlOutputStyle));
			return;
		}
	}
}

void generateModulePage(OutputStream)(OutputStream dst, Package root_package, Module mod, GeneratorSettings settings, string delegate(in Entity) link_to, HTTPServerRequest req = null)
	if (isOutputStream!OutputStream)
{
	auto info = new DocPageInfo;
	info.linkTo = link_to;
	info.settings = settings;
	info.rootPackage = root_package;
	info.mod = mod;
	info.node = mod;
	info.docGroups = null;

	auto rng = streamOutputRange(dst);
	final switch (settings.htmlOutputStyle)
	{
		foreach (htmlOutputStyle; EnumMembers!HTMLOutputStyle)
		case htmlOutputStyle:
		{
			rng.compileHTMLDietFile!("ddox.module.dt", req, info, DdoxDietTraits!(htmlOutputStyle));
			return;
		}
	}
}

void generateDeclPage(OutputStream)(OutputStream dst, Package root_package, Module mod, string nested_name, DocGroup[] docgroups, GeneratorSettings settings, string delegate(in Entity) link_to, HTTPServerRequest req = null)
	if (isOutputStream!OutputStream)
{
	import std.algorithm : sort;

	auto info = new DocPageInfo;
	info.linkTo = link_to;
	info.settings = settings;
	info.rootPackage = root_package;
	info.mod = mod;
	info.node = mod;
	info.docGroups = docgroups;//docGroups(mod.lookupAll!Declaration(nested_name));
	sort!((a, b) => cmpKind(a.members[0], b.members[0]))(info.docGroups);
	info.nestedName = nested_name;

	auto rng = streamOutputRange(dst);
	final switch (settings.htmlOutputStyle)
	{
		foreach (htmlOutputStyle; EnumMembers!HTMLOutputStyle)
		case htmlOutputStyle:
		{
			rng.compileHTMLDietFile!("ddox.docpage.dt", req, info, DdoxDietTraits!(htmlOutputStyle));
			return;
		}
	}
}

private bool cmpKind(in Entity a, in Entity b)
{
	static immutable kinds = [
		DeclarationKind.Variable,
		DeclarationKind.Function,
		DeclarationKind.Struct,
		DeclarationKind.Union,
		DeclarationKind.Class,
		DeclarationKind.Interface,
		DeclarationKind.Enum,
		DeclarationKind.EnumMember,
		DeclarationKind.Template,
		DeclarationKind.TemplateParameter,
		DeclarationKind.Alias
	];

	auto ad = cast(const(Declaration))a;
	auto bd = cast(const(Declaration))b;

	if (!ad && !bd) return false;
	if (!ad) return false;
	if (!bd) return true;

	auto ak = kinds.countUntil(ad.kind);
	auto bk = kinds.countUntil(bd.kind);

	if (ak < 0 && bk < 0) return false;
	if (ak < 0) return false;
	if (bk < 0) return true;

	return ak < bk;
}