package buildstep

import (
	"context"
	"strings"
	"testing"

	"git.novox.be/novox/mesh-sdk/go/forgekey"
)

const sha = "0123456789abcdef0123456789abcdef01234567"

// fakeGit records every command and answers by a rule.
type fakeGit struct {
	calls []string
	envs  [][]string
	rule  func(args string) forgekey.Ran
}

func (f *fakeGit) run(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
	line := name + " " + strings.Join(args, " ")
	f.calls = append(f.calls, line)
	f.envs = append(f.envs, env)
	if f.rule != nil {
		if r := f.rule(line); r.Status != 0 || r.Stdout != "" || r.Err != "" {
			return r
		}
	}
	if len(args) > 4 && args[4] == "rev-parse" {
		return forgekey.Ran{Stdout: sha + "\n"}
	}
	return forgekey.Ran{}
}

const pre = "git -c credential.helper= -C /w "

// 1474/AC1: the git commands are exactly the sequence, none with a credential or an https remote.
func TestFetchCommitRunsTheSequence(t *testing.T) {
	f := &fakeGit{}
	if err := FetchCommit(context.Background(), f.run, "/w", "ssh://mesh-forge/novox/mesh-sdk.git", sha, ""); err != nil {
		t.Fatal(err)
	}
	want := []string{
		pre + "init -q",
		pre + "remote add origin ssh://mesh-forge/novox/mesh-sdk.git",
		pre + "fetch --no-tags --depth 1 origin " + sha,
		pre + "checkout -q --detach " + sha,
		pre + "rev-parse HEAD",
	}
	if strings.Join(f.calls, "\n") != strings.Join(want, "\n") {
		t.Errorf("commands:\n%s\nwant:\n%s", strings.Join(f.calls, "\n"), strings.Join(want, "\n"))
	}
	for i, c := range f.calls {
		if strings.Contains(c, "https://") || strings.Contains(c, "@") || !strings.Contains(c, "credential.helper= ") {
			t.Errorf("command %q carries a credential or https", c)
		}
		if len(f.envs[i]) != 1 || f.envs[i][0] != "GIT_TERMINAL_PROMPT=0" {
			t.Errorf("env %v", f.envs[i])
		}
	}
}

// 1474/AC2: the depth-1 fetch fails and a pull ref is given: the ref is fetched and the commit verified; with no
// ref, the fetch's failure is the answer.
func TestFetchCommitFallsBackToThePullRef(t *testing.T) {
	f := &fakeGit{rule: func(l string) forgekey.Ran {
		if strings.Contains(l, "--depth 1") {
			return forgekey.Ran{Status: 128, Stderr: "fatal: couldn't find remote ref " + sha + "\n"}
		}
		return forgekey.Ran{}
	}}
	if err := FetchCommit(context.Background(), f.run, "/w", "ssh://mesh-forge/o/r.git", sha, "refs/pull/1/head"); err != nil {
		t.Fatal(err)
	}
	want := []string{pre + "fetch --no-tags origin refs/pull/1/head", pre + "cat-file -e " + sha + "^{commit}", pre + "checkout -q --detach " + sha}
	got := strings.Join(f.calls[3:6], "\n")
	if got != strings.Join(want, "\n") {
		t.Errorf("after the failed fetch:\n%s\nwant:\n%s", got, strings.Join(want, "\n"))
	}

	g := &fakeGit{rule: f.rule}
	err := FetchCommit(context.Background(), g.run, "/w", "ssh://mesh-forge/o/r.git", sha, "")
	if err == nil || !strings.Contains(err.Error(), "couldn't find remote ref") || len(g.calls) != 3 {
		t.Errorf("without a ref: %v after %d commands", err, len(g.calls))
	}

	h := &fakeGit{rule: func(l string) forgekey.Ran {
		if strings.Contains(l, "--depth 1") || strings.Contains(l, "cat-file") {
			return forgekey.Ran{Status: 1, Stderr: "no"}
		}
		return forgekey.Ran{}
	}}
	if err := FetchCommit(context.Background(), h.run, "/w", "ssh://mesh-forge/o/r.git", sha, "refs/pull/1/head"); err == nil {
		t.Error("a commit that is not in the ref was accepted")
	}
}

// 1474/AC3: HEAD differs from the commit after the checkout: an error naming both.
func TestFetchCommitAnswersAHeadThatIsNotTheCommit(t *testing.T) {
	other := strings.Repeat("a", 40)
	f := &fakeGit{rule: func(l string) forgekey.Ran {
		if strings.HasSuffix(l, "rev-parse HEAD") {
			return forgekey.Ran{Stdout: other + "\n"}
		}
		return forgekey.Ran{}
	}}
	err := FetchCommit(context.Background(), f.run, "/w", "ssh://mesh-forge/o/r.git", sha, "")
	if err == nil || !strings.Contains(err.Error(), other) || !strings.Contains(err.Error(), sha) {
		t.Errorf("error = %v, want both shas", err)
	}
}

// 1474/AC4: an https remote, user information, a file remote without the option, or a commit that is not 40
// hex digits is refused before anything runs.
func TestFetchCommitRefusesBeforeRunningAnything(t *testing.T) {
	for _, c := range []struct{ remote, commit, ref string }{
		{"https://forge.example/o/r.git", sha, ""},
		{"http://forge.example/o/r.git", sha, ""},
		{"ssh://git@mesh-forge/o/r.git", sha, ""},
		{"ssh://user:pw@mesh-forge/o/r.git", sha, ""},
		{"file:///tmp/r.git", sha, ""},
		{"/tmp/r.git", sha, ""},
		{"ssh://mesh-forge/o/r.git", "abc123", ""},
		{"ssh://mesh-forge/o/r.git", strings.ToUpper(sha), ""},
		{"ssh://mesh-forge/o/r.git", "main", ""},
		{"ssh://mesh-forge/o/r.git", sha, "--upload-pack=x"},
	} {
		f := &fakeGit{}
		if err := FetchCommit(context.Background(), f.run, "/w", c.remote, c.commit, c.ref); err == nil || len(f.calls) != 0 {
			t.Errorf("%+v: err %v, %d commands", c, err, len(f.calls))
		}
	}
	f := &fakeGit{}
	if err := FetchCommit(context.Background(), f.run, "/w", "file:///tmp/r.git", sha, "", AllowFileRemote()); err != nil {
		t.Errorf("a file remote with the option: %v", err)
	}
}