// Copyright 2019 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_test

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"testing"

	"golang.org/x/tools/go/packages/packagestest"
	"golang.org/x/tools/internal/lsp/cmd"
	"golang.org/x/tools/internal/span"
	"golang.org/x/tools/internal/tool"
)

const (
	expectedDefinitionsCount     = 25
	expectedTypeDefinitionsCount = 2
)

type definition struct {
	src   span.Span
	flags string
	def   span.Span
	match string
}

type definitions map[span.Span]definition

var verifyGuru = flag.Bool("verify-guru", false, "Check that the guru compatability matches")

func TestDefinitionHelpExample(t *testing.T) {
	if runtime.GOOS == "android" {
		t.Skip("not all source files are available on android")
	}
	dir, err := os.Getwd()
	if err != nil {
		t.Errorf("could not get wd: %v", err)
		return
	}
	thisFile := filepath.Join(dir, "definition.go")
	baseArgs := []string{"query", "definition"}
	expect := regexp.MustCompile(`^[\w/\\:_-]+flag[/\\]flag.go:\d+:\d+-\d+: defined here as type flag.FlagSet struct{.*}$`)
	for _, query := range []string{
		fmt.Sprintf("%v:%v:%v", thisFile, cmd.ExampleLine, cmd.ExampleColumn),
		fmt.Sprintf("%v:#%v", thisFile, cmd.ExampleOffset)} {
		args := append(baseArgs, query)
		got := captureStdOut(t, func() {
			tool.Main(context.Background(), &cmd.Application{}, args)
		})
		if !expect.MatchString(got) {
			t.Errorf("test with %v\nexpected:\n%s\ngot:\n%s", args, expect, got)
		}
	}
}

func (l definitions) godef(src, def span.Span) {
	l[src] = definition{
		src: src,
		def: def,
	}
}

func (l definitions) typdef(src, def span.Span) {
	l[src] = definition{
		src: src,
		def: def,
	}
}

func (l definitions) definition(src span.Span, flags string, def span.Span, match string) {
	l[src] = definition{
		src:   src,
		flags: flags,
		def:   def,
		match: match,
	}
}

func (l definitions) testDefinitions(t *testing.T, e *packagestest.Exported) {
	if len(l) != expectedDefinitionsCount {
		t.Errorf("got %v definitions expected %v", len(l), expectedDefinitionsCount)
	}
	for _, d := range l {
		args := []string{"query"}
		if d.flags != "" {
			args = append(args, strings.Split(d.flags, " ")...)
		}
		args = append(args, "definition")
		src := span.New(d.src.URI(), span.NewPoint(0, 0, d.src.Start().Offset()), span.Point{})
		args = append(args, fmt.Sprint(src))
		app := &cmd.Application{}
		app.Config = *e.Config
		got := captureStdOut(t, func() {
			tool.Main(context.Background(), app, args)
		})
		if d.match == "" {
			expect := fmt.Sprint(d.def)
			if !strings.HasPrefix(got, expect) {
				t.Errorf("definition %v\nexpected:\n%s\ngot:\n%s", args, expect, got)
			}
		} else {
			expect := os.Expand(d.match, func(name string) string {
				switch name {
				case "file":
					fname, _ := d.def.URI().Filename()
					return fname
				case "efile":
					fname, _ := d.def.URI().Filename()
					qfile := strconv.Quote(fname)
					return qfile[1 : len(qfile)-1]
				case "euri":
					quri := strconv.Quote(string(d.def.URI()))
					return quri[1 : len(quri)-1]
				case "line":
					return fmt.Sprint(d.def.Start().Line())
				case "col":
					return fmt.Sprint(d.def.Start().Column())
				case "offset":
					return fmt.Sprint(d.def.Start().Offset())
				case "eline":
					return fmt.Sprint(d.def.End().Line())
				case "ecol":
					return fmt.Sprint(d.def.End().Column())
				case "eoffset":
					return fmt.Sprint(d.def.End().Offset())
				default:
					return name
				}
			})
			if expect != got {
				t.Errorf("definition %v\nexpected:\n%s\ngot:\n%s", args, expect, got)
			}
			if *verifyGuru {
				moduleMode := e.File(e.Modules[0].Name, "go.mod") != ""
				var guruArgs []string
				runGuru := false
				if !moduleMode {
					for _, arg := range args {
						switch {
						case arg == "query":
							// just ignore this one
						case arg == "-json":
							guruArgs = append(guruArgs, arg)
						case arg == "-emulate=guru":
							// if we don't see this one we should not run guru
							runGuru = true
						case strings.HasPrefix(arg, "-"):
							// unknown flag, ignore it
							break
						default:
							guruArgs = append(guruArgs, arg)
						}
					}
				}
				if runGuru {
					cmd := exec.Command("guru", guruArgs...)
					cmd.Env = e.Config.Env
					out, err := cmd.CombinedOutput()
					if err != nil {
						t.Errorf("Could not run guru %v: %v\n%s", guruArgs, err, out)
					} else {
						guru := strings.TrimSpace(string(out))
						if !strings.HasPrefix(expect, guru) {
							t.Errorf("definition %v\nexpected:\n%s\nguru gave:\n%s", args, expect, guru)
						}
					}
				}
			}
		}
	}
}

func (l definitions) testTypeDefinitions(t *testing.T, e *packagestest.Exported) {
	if len(l) != expectedTypeDefinitionsCount {
		t.Errorf("got %v definitions expected %v", len(l), expectedTypeDefinitionsCount)
	}
	//TODO: add command line type definition tests when it works
}