package e2emutate

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"strings"
	"testing"
)

type fakeHTTP struct {
	do    func(*http.Request) (*http.Response, error)
	calls []*http.Request
}

func (f *fakeHTTP) Do(request *http.Request) (*http.Response, error) {
	f.calls = append(f.calls, request)
	return f.do(request)
}

func mutationResponse(status int, body string) *http.Response {
	return &http.Response{StatusCode: status, Body: io.NopCloser(strings.NewReader(body)), Header: make(http.Header)}
}

func testOptions() Options {
	return Options{
		ForgejoURL: "https://git.example.test",
		Owner:      "Maidn",
		Repo:       "maidn-e2e-repo",
		Branch:     "maidn-e2e-branch",
		SHA:        "0123456789abcdef0123456789abcdef01234567",
		Token:      "test-token",
	}
}

func TestOptionsValidateAcceptsOnlyFixtureTargets(t *testing.T) {
	if err := testOptions().Validate(); err != nil {
		t.Fatalf("valid fixture options: %v", err)
	}
	for _, update := range []func(*Options){
		func(o *Options) { o.Owner = "other-org" },
		func(o *Options) { o.Repo = "production" },
		func(o *Options) { o.Branch = "feature/maidn-e2e-branch" },
		func(o *Options) { o.Branch = "maidn-e2e-branch..unsafe" },
		func(o *Options) { o.Repo = "maidn-e2e-repo.lock" },
	} {
		options := testOptions()
		update(&options)
		if err := options.Validate(); err == nil {
			t.Fatalf("Validate accepted %#v", options)
		}
	}
}

func TestMutatorUpdatesFixtureRefAndEnsuresOnePR(t *testing.T) {
	fake := &fakeHTTP{do: func(request *http.Request) (*http.Response, error) {
		if request.Header.Get("Authorization") != "token test-token" {
			t.Fatal("mutation request did not authenticate at the API boundary")
		}
		switch {
		case request.Method == http.MethodPatch && request.URL.Path == "/api/v1/repos/Maidn/maidn-e2e-repo/git/refs/heads/maidn-e2e-branch":
			var body struct {
				SHA   string `json:"sha"`
				Force bool   `json:"force"`
			}
			if err := json.NewDecoder(request.Body).Decode(&body); err != nil || body.SHA != testOptions().SHA || body.Force {
				t.Fatalf("unexpected branch update: %#v, %v", body, err)
			}
			return mutationResponse(http.StatusOK, ""), nil
		case request.Method == http.MethodGet && request.URL.Path == "/api/v1/repos/Maidn/maidn-e2e-repo/pulls":
			if request.URL.Query().Get("head") != "Maidn:maidn-e2e-branch" || request.URL.Query().Get("state") != "open" {
				t.Fatal("pull request lookup did not target the fixture branch")
			}
			return mutationResponse(http.StatusOK, "[]"), nil
		case request.Method == http.MethodPost && request.URL.Path == "/api/v1/repos/Maidn/maidn-e2e-repo/pulls":
			var body struct {
				Head string `json:"head"`
				Base string `json:"base"`
			}
			if err := json.NewDecoder(request.Body).Decode(&body); err != nil || body.Head != "maidn-e2e-branch" || body.Base != "main" {
				t.Fatalf("unexpected pull request creation: %#v, %v", body, err)
			}
			return mutationResponse(http.StatusCreated, ""), nil
		default:
			t.Fatalf("unexpected Forgejo request: %s %s", request.Method, request.URL)
			return nil, nil
		}
	}}
	options := testOptions()
	options.OpenPR = true
	if err := (Mutator{HTTP: fake}).Run(context.Background(), options); err != nil || len(fake.calls) != 3 {
		t.Fatalf("Run() = %v, calls = %d", err, len(fake.calls))
	}
}

func TestMutatorCreatesFixtureRefWhenAbsent(t *testing.T) {
	fake := &fakeHTTP{do: func(request *http.Request) (*http.Response, error) {
		switch request.Method {
		case http.MethodPatch:
			return mutationResponse(http.StatusNotFound, ""), nil
		case http.MethodPost:
			if request.URL.Path != "/api/v1/repos/Maidn/maidn-e2e-repo/git/refs" {
				t.Fatalf("branch creation targeted %q", request.URL.Path)
			}
			return mutationResponse(http.StatusCreated, ""), nil
		default:
			t.Fatalf("unexpected Forgejo request: %s %s", request.Method, request.URL)
			return nil, nil
		}
	}}
	if err := (Mutator{HTTP: fake}).Run(context.Background(), testOptions()); err != nil || len(fake.calls) != 2 {
		t.Fatalf("Run() = %v, calls = %d", err, len(fake.calls))
	}
}

func TestMutatorRejectsUnsafeTargetsBeforeAPIAndDoesNotExposeToken(t *testing.T) {
	fake := &fakeHTTP{do: func(*http.Request) (*http.Response, error) {
		t.Fatal("unsafe target reached the Forgejo API")
		return nil, nil
	}}
	options := testOptions()
	options.Owner = "production"
	options.Token = "secret-token"
	err := (Mutator{HTTP: fake}).Run(context.Background(), options)
	if err == nil || strings.Contains(err.Error(), options.Token) {
		t.Fatalf("Run() returned unsafe error: %v", err)
	}

	fake.do = func(*http.Request) (*http.Response, error) { return nil, errors.New(options.Token) }
	options = testOptions()
	options.Token = "secret-token"
	err = (Mutator{HTTP: fake}).Run(context.Background(), options)
	if err == nil || strings.Contains(err.Error(), options.Token) {
		t.Fatalf("Run() exposed token: %v", err)
	}
}