// Copyright 2020 The Fuchsia 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 langserver

import (
	"strings"

	"github.com/sourcegraph/go-lsp"

	"fidl-lsp/state"
)

// handleFormat asks the Analyzer for the formatted version of the document
// specified in `params` and returns any resulting TextEdits, or an error.
//
// In practice, since fidl-format only runs on an entire document, when
// successful this will always return a single TextEdit spanning (and replacing)
// the entire document with its formatted version.
func (h *LangHandler) handleFormat(params lsp.DocumentFormattingParams) ([]lsp.TextEdit, error) {
	formatted, err := h.analyzer.FormatFile(h.fs, state.FileID(params.TextDocument.URI))
	if err != nil {
		return nil, err
	}

	lines := strings.Split(formatted, "\n")
	lastLine := lines[len(lines)-1]
	lastChar := len([]rune(lastLine))

	return []lsp.TextEdit{{
		Range: lsp.Range{
			Start: lsp.Position{},
			End:   lsp.Position{Line: len(lines), Character: lastChar},
		},
		NewText: formatted,
	}}, nil
}