// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package lsp

import (
	"context"
	"fmt"
	"net"
	"sync"

	"golang.org/x/tools/internal/jsonrpc2"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/span"
)

// NewClientServer
func NewClientServer(ctx context.Context, cache source.Cache, client protocol.Client) (context.Context, *Server) {
	ctx = protocol.WithClient(ctx, client)
	return ctx, &Server{
		client:  client,
		session: cache.NewSession(ctx),
	}
}

// NewServer starts an LSP server on the supplied stream, and waits until the
// stream is closed.
func NewServer(ctx context.Context, cache source.Cache, stream jsonrpc2.Stream) (context.Context, *Server) {
	s := &Server{}
	ctx, s.Conn, s.client = protocol.NewServer(ctx, stream, s)
	s.session = cache.NewSession(ctx)
	return ctx, s
}

// RunServerOnPort starts an LSP server on the given port and does not exit.
// This function exists for debugging purposes.
func RunServerOnPort(ctx context.Context, cache source.Cache, port int, h func(ctx context.Context, s *Server)) error {
	return RunServerOnAddress(ctx, cache, fmt.Sprintf(":%v", port), h)
}

// RunServerOnPort starts an LSP server on the given port and does not exit.
// This function exists for debugging purposes.
func RunServerOnAddress(ctx context.Context, cache source.Cache, addr string, h func(ctx context.Context, s *Server)) error {
	ln, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}
	for {
		conn, err := ln.Accept()
		if err != nil {
			return err
		}
		h(NewServer(ctx, cache, jsonrpc2.NewHeaderStream(conn, conn)))
	}
}

func (s *Server) Run(ctx context.Context) error {
	return s.Conn.Run(ctx)
}

type serverState int

const (
	serverCreated      = serverState(iota)
	serverInitializing // set once the server has received "initialize" request
	serverInitialized  // set once the server has received "initialized" request
	serverShutDown
)

type Server struct {
	Conn   *jsonrpc2.Conn
	client protocol.Client

	stateMu sync.Mutex
	state   serverState

	// Configurations.
	// TODO(rstambler): Separate these into their own struct?
	usePlaceholders               bool
	hoverKind                     hoverKind
	disableDeepCompletion         bool
	disableFuzzyMatching          bool
	watchFileChanges              bool
	wantCompletionDocumentation   bool
	wantUnimportedCompletions     bool
	insertTextFormat              protocol.InsertTextFormat
	configurationSupported        bool
	dynamicConfigurationSupported bool
	dynamicWatchedFilesSupported  bool
	preferredContentFormat        protocol.MarkupKind
	disabledAnalyses              map[string]struct{}
	wantSuggestedFixes            bool

	supportedCodeActions map[source.FileKind]map[protocol.CodeActionKind]bool

	textDocumentSyncKind protocol.TextDocumentSyncKind

	session source.Session

	// undelivered is a cache of any diagnostics that the server
	// failed to deliver for some reason.
	undeliveredMu sync.Mutex
	undelivered   map[span.URI][]source.Diagnostic
}

// General

func (s *Server) Initialize(ctx context.Context, params *protocol.InitializeParams) (*protocol.InitializeResult, error) {
	return s.initialize(ctx, params)
}

func (s *Server) Initialized(ctx context.Context, params *protocol.InitializedParams) error {
	return s.initialized(ctx, params)
}

func (s *Server) Shutdown(ctx context.Context) error {
	return s.shutdown(ctx)
}

func (s *Server) Exit(ctx context.Context) error {
	return s.exit(ctx)
}

// Workspace

func (s *Server) DidChangeWorkspaceFolders(ctx context.Context, params *protocol.DidChangeWorkspaceFoldersParams) error {
	return s.changeFolders(ctx, params.Event)
}

func (s *Server) DidChangeConfiguration(context.Context, *protocol.DidChangeConfigurationParams) error {
	return notImplemented("DidChangeConfiguration")
}

func (s *Server) DidChangeWatchedFiles(ctx context.Context, params *protocol.DidChangeWatchedFilesParams) error {
	return s.didChangeWatchedFiles(ctx, params)
}

func (s *Server) Symbol(context.Context, *protocol.WorkspaceSymbolParams) ([]protocol.SymbolInformation, error) {
	return nil, notImplemented("Symbol")
}

func (s *Server) ExecuteCommand(context.Context, *protocol.ExecuteCommandParams) (interface{}, error) {
	return nil, notImplemented("ExecuteCommand")
}

// Text Synchronization

func (s *Server) DidOpen(ctx context.Context, params *protocol.DidOpenTextDocumentParams) error {
	return s.didOpen(ctx, params)
}

func (s *Server) DidChange(ctx context.Context, params *protocol.DidChangeTextDocumentParams) error {
	return s.didChange(ctx, params)
}

func (s *Server) WillSave(context.Context, *protocol.WillSaveTextDocumentParams) error {
	return notImplemented("WillSave")
}

func (s *Server) WillSaveWaitUntil(context.Context, *protocol.WillSaveTextDocumentParams) ([]protocol.TextEdit, error) {
	return nil, notImplemented("WillSaveWaitUntil")
}

func (s *Server) DidSave(ctx context.Context, params *protocol.DidSaveTextDocumentParams) error {
	return s.didSave(ctx, params)
}

func (s *Server) DidClose(ctx context.Context, params *protocol.DidCloseTextDocumentParams) error {
	return s.didClose(ctx, params)
}

// Language Features

func (s *Server) Completion(ctx context.Context, params *protocol.CompletionParams) (*protocol.CompletionList, error) {
	return s.completion(ctx, params)
}

func (s *Server) Resolve(ctx context.Context, item *protocol.CompletionItem) (*protocol.CompletionItem, error) {
	return nil, notImplemented("completionItem/resolve")
}

func (s *Server) Hover(ctx context.Context, params *protocol.TextDocumentPositionParams) (*protocol.Hover, error) {
	return s.hover(ctx, params)
}

func (s *Server) SignatureHelp(ctx context.Context, params *protocol.TextDocumentPositionParams) (*protocol.SignatureHelp, error) {
	return s.signatureHelp(ctx, params)
}

func (s *Server) Definition(ctx context.Context, params *protocol.TextDocumentPositionParams) ([]protocol.Location, error) {
	return s.definition(ctx, params)
}

func (s *Server) TypeDefinition(ctx context.Context, params *protocol.TextDocumentPositionParams) ([]protocol.Location, error) {
	return s.typeDefinition(ctx, params)
}

func (s *Server) Implementation(context.Context, *protocol.TextDocumentPositionParams) ([]protocol.Location, error) {
	return nil, notImplemented("Implementation")
}

func (s *Server) References(ctx context.Context, params *protocol.ReferenceParams) ([]protocol.Location, error) {
	return s.references(ctx, params)
}

func (s *Server) DocumentHighlight(ctx context.Context, params *protocol.TextDocumentPositionParams) ([]protocol.DocumentHighlight, error) {
	return s.documentHighlight(ctx, params)
}

func (s *Server) DocumentSymbol(ctx context.Context, params *protocol.DocumentSymbolParams) ([]protocol.DocumentSymbol, error) {
	return s.documentSymbol(ctx, params)
}

func (s *Server) CodeAction(ctx context.Context, params *protocol.CodeActionParams) ([]protocol.CodeAction, error) {
	return s.codeAction(ctx, params)
}

func (s *Server) CodeLens(context.Context, *protocol.CodeLensParams) ([]protocol.CodeLens, error) {
	return nil, nil // ignore
}

func (s *Server) ResolveCodeLens(context.Context, *protocol.CodeLens) (*protocol.CodeLens, error) {
	return nil, notImplemented("ResolveCodeLens")
}

func (s *Server) DocumentLink(ctx context.Context, params *protocol.DocumentLinkParams) ([]protocol.DocumentLink, error) {
	return s.documentLink(ctx, params)
}

func (s *Server) ResolveDocumentLink(context.Context, *protocol.DocumentLink) (*protocol.DocumentLink, error) {
	return nil, notImplemented("ResolveDocumentLink")
}

func (s *Server) DocumentColor(context.Context, *protocol.DocumentColorParams) ([]protocol.ColorInformation, error) {
	return nil, notImplemented("DocumentColor")
}

func (s *Server) ColorPresentation(context.Context, *protocol.ColorPresentationParams) ([]protocol.ColorPresentation, error) {
	return nil, notImplemented("ColorPresentation")
}

func (s *Server) Formatting(ctx context.Context, params *protocol.DocumentFormattingParams) ([]protocol.TextEdit, error) {
	return s.formatting(ctx, params)
}

func (s *Server) RangeFormatting(ctx context.Context, params *protocol.DocumentRangeFormattingParams) ([]protocol.TextEdit, error) {
	return nil, notImplemented("RangeFormatting")
}

func (s *Server) OnTypeFormatting(context.Context, *protocol.DocumentOnTypeFormattingParams) ([]protocol.TextEdit, error) {
	return nil, notImplemented("OnTypeFormatting")
}

func (s *Server) Rename(ctx context.Context, params *protocol.RenameParams) (*protocol.WorkspaceEdit, error) {
	return s.rename(ctx, params)
}

func (s *Server) Declaration(context.Context, *protocol.TextDocumentPositionParams) ([]protocol.DeclarationLink, error) {
	return nil, notImplemented("Declaration")
}

func (s *Server) FoldingRange(ctx context.Context, params *protocol.FoldingRangeParams) ([]protocol.FoldingRange, error) {
	return s.foldingRange(ctx, params)
}

func (s *Server) LogTraceNotification(context.Context, *protocol.LogTraceParams) error {
	return notImplemented("LogtraceNotification")
}

func (s *Server) PrepareRename(ctx context.Context, params *protocol.TextDocumentPositionParams) (*protocol.Range, error) {
	// TODO(suzmue): support sending placeholder text.
	return s.prepareRename(ctx, params)
}

func (s *Server) SetTraceNotification(context.Context, *protocol.SetTraceParams) error {
	return notImplemented("SetTraceNotification")
}

func (s *Server) SelectionRange(context.Context, *protocol.SelectionRangeParams) ([]protocol.SelectionRange, error) {
	return nil, notImplemented("SelectionRange")
}

func notImplemented(method string) *jsonrpc2.Error {
	return jsonrpc2.NewErrorf(jsonrpc2.CodeMethodNotFound, "method %q not yet implemented", method)
}