// 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 analysis

import (
	"encoding/json"
	"fmt"
	"os/exec"

	"fidl-lsp/third_party/fidlgen"

	"fidl-lsp/state"
)

// DiagnosticsOnLibrary retrieves the cached diagnostics for the library with
// name `libName` including the file `path`.
func (a *Analyzer) DiagnosticsOnLibrary(libName fidlgen.LibraryName, path state.FileID) (map[state.FileID][]Diagnostic, error) {
	lib, ok := a.getLibraryWithFile(libName, path)
	if !ok {
		return nil, fmt.Errorf("could not find library `%s`", libName)
	}
	return lib.diags, nil
}

type fidlLintSuggestion struct {
	Description string
}

type FidlcTool string

const (
	Fidlc    FidlcTool = "fidlc"
	FidlLint           = "fidl-lint"
)

// Diagnostic represents an {error, warning, lint} deserialized from the JSON
// output of fidlc or fidl-lint.
type Diagnostic struct {
	Source      FidlcTool
	Category    string
	Message     string
	Path        string
	StartLine   int `json:"start_line"`
	StartChar   int `json:"start_char"`
	EndLine     int `json:"end_line"`
	EndChar     int `json:"end_char"`
	Suggestions []fidlLintSuggestion
}

func (a *Analyzer) fidlcDiagsFromStderr(stderr []byte) (map[state.FileID][]Diagnostic, error) {
	// Deserialize stderr into []Diagnostic
	var diags []Diagnostic
	if err := json.Unmarshal(stderr, &diags); err != nil {
		return nil, fmt.Errorf("could not deserialize fidlc diagnostics: `%s`", err)
	}
	fileToDiags := make(map[state.FileID][]Diagnostic)
	for i := range diags {
		fileID, err := a.inputFileToFileID(diags[i].Path)
		if err != nil {
			continue
		}
		if _, ok := fileToDiags[fileID]; !ok {
			fileToDiags[fileID] = []Diagnostic{}
		}
		diags[i].Source = Fidlc
		fileToDiags[fileID] = append(fileToDiags[fileID], diags[i])
	}
	return fileToDiags, nil
}

func (a *Analyzer) runFidlLint(path string) (map[state.FileID][]Diagnostic, error) {
	// TODO: return early with an error if we got status code != 0 or 1?
	// Otherwise, ignore err: we expect this to fail with status code 1 if there
	// are any lints from fidl-lint.
	out, _ := exec.Command(a.cfg.FidlLintPath, "--format=json", path).Output()

	// Deserialize stdout into []fidlLint
	var diags []Diagnostic
	if err := json.Unmarshal(out, &diags); err != nil {
		return nil, fmt.Errorf("error deserializing fidl-lint output: %s", err)
	}
	fileToDiags := make(map[state.FileID][]Diagnostic)
	for i := range diags {
		fileID, err := a.inputFileToFileID(diags[i].Path)
		if err != nil {
			continue
		}
		if _, ok := fileToDiags[fileID]; !ok {
			fileToDiags[fileID] = []Diagnostic{}
		}
		diags[i].Source = FidlLint
		fileToDiags[fileID] = append(fileToDiags[fileID], diags[i])
	}
	return fileToDiags, nil
}