// 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 (
	"context"
	"fmt"
	"strings"

	"fidl-lsp/third_party/fidlgen"
	"github.com/sourcegraph/go-lsp"
	"github.com/sourcegraph/jsonrpc2"

	"fidl-lsp/analysis"
	"fidl-lsp/state"
)

func (h *LangHandler) publishDiagnostics(ctx context.Context, conn *jsonrpc2.Conn, uri lsp.DocumentURI) {
	diags, err := h.getDiagnosticsForLibraryWithFile(uri)
	if err != nil {
		h.log.Printf("error publishing diagnostics: %s\n", err)
		return
	}

	for fileURI, fileDiags := range diags {
		h.Notify(ctx, conn, "textDocument/publishDiagnostics", lsp.PublishDiagnosticsParams{
			URI:         fileURI,
			Diagnostics: fileDiags,
		})
	}
}

func (h *LangHandler) getDiagnosticsForLibraryWithFile(uri lsp.DocumentURI) (map[lsp.DocumentURI][]lsp.Diagnostic, error) {
	file, err := h.fs.File(state.FileID(uri))
	if err != nil {
		return nil, fmt.Errorf("could not find file `%s`: %s", uri, err)
	}
	libraryName, err := state.LibraryOfFile(file)
	if err != nil {
		return nil, fmt.Errorf("could not find library name of file `%s`: %s", uri, err)
	}

	diags, err := h.analyzer.DiagnosticsOnLibrary(fidlgen.LibraryName(libraryName), state.FileID(uri))
	if err != nil {
		return nil, fmt.Errorf("error getting diagnostics: %s", err)
	}

	// Convert analysis.Diagnostics --> lsp.Diagnostics
	lspDiags := make(map[lsp.DocumentURI][]lsp.Diagnostic)
	for fileID, fileDiags := range diags {
		fileURI := lsp.DocumentURI(fileID)
		lspDiags[fileURI] = []lsp.Diagnostic{}

		for _, diag := range fileDiags {
			var severity lsp.DiagnosticSeverity
			message := diag.Message

			switch diag.Source {
			case analysis.Fidlc:
				diagType := strings.Split(diag.Category, "/")[1]
				if diagType == "error" {
					severity = lsp.Error
				} else {
					severity = lsp.Warning
				}
			case analysis.FidlLint:
				severity = lsp.Warning
				if len(diag.Suggestions) > 0 {
					message = message + "; " + diag.Suggestions[0].Description
				}
			}

			lspDiags[fileURI] = append(lspDiags[fileURI], lsp.Diagnostic{
				Range: lsp.Range{
					Start: lsp.Position{Line: diag.StartLine - 1, Character: diag.StartChar},
					End:   lsp.Position{Line: diag.EndLine - 1, Character: diag.EndChar},
				},
				Severity: severity,
				Source:   string(diag.Source),
				Message:  message,
			})
		}
	}
	return lspDiags, nil
}