// Copyright 2022 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 cmd

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"os"

	"golang.org/x/tools/go/packages"
	"golang.org/x/tools/internal/lsp/command"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/tool"
)

// vulncheck implements the vulncheck command.
type vulncheck struct {
	app *Application
}

func (v *vulncheck) Name() string   { return "vulncheck" }
func (v *vulncheck) Parent() string { return v.app.Name() }
func (v *vulncheck) Usage() string  { return "" }
func (v *vulncheck) ShortHelp() string {
	return "run experimental vulncheck analysis (experimental: under development)"
}
func (v *vulncheck) DetailedHelp(f *flag.FlagSet) {
	fmt.Fprint(f.Output(), `
	WARNING: this command is experimental.

	By default, the command outputs a JSON-encoded
	golang.org/x/tools/internal/lsp/command.VulncheckResult
	message.

	Example:
	$ gopls vulncheck <packages>
`)
	printFlagDefaults(f)
}

func (v *vulncheck) Run(ctx context.Context, args ...string) error {
	if len(args) > 1 {
		return tool.CommandLineErrorf("vulncheck accepts at most one package pattern")
	}
	pattern := "."
	if len(args) == 1 {
		pattern = args[0]
	}

	cwd, err := os.Getwd()
	if err != nil {
		return tool.CommandLineErrorf("failed to get current directory: %v", err)
	}

	opts := source.DefaultOptions().Clone()
	v.app.options(opts) // register hook
	if opts == nil || opts.Hooks.Govulncheck == nil {
		return tool.CommandLineErrorf("vulncheck feature is not available")
	}

	loadCfg := &packages.Config{
		Context: ctx,
	}

	res, err := opts.Hooks.Govulncheck(ctx, loadCfg, command.VulncheckArgs{
		Dir:     protocol.URIFromPath(cwd),
		Pattern: pattern,
	})
	if err != nil {
		return err
	}
	data, err := json.MarshalIndent(res, " ", " ")
	if err != nil {
		return fmt.Errorf("failed to decode results: %v", err)
	}
	fmt.Printf("%s", data)
	return nil
}