package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"net/http/httptest"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"testing"

	"git.unkin.net/unkin/agent-tools/internal/agent"
)

// fixture is a bare origin plus a source checkout named "repo" and a worktree
// root, wired so managedWorktrees() finds the worktrees created here.
type fixture struct {
	root   string
	bare   string
	srcDir string
	wtRoot string
}

func git(t *testing.T, dir string, args ...string) string {
	t.Helper()
	cmd := exec.Command("git", args...)
	cmd.Dir = dir
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("git %s (in %s): %v: %s", strings.Join(args, " "), dir, err, out)
	}
	return strings.TrimSpace(string(out))
}

func newFixture(t *testing.T) *fixture {
	t.Helper()
	root := t.TempDir()
	f := &fixture{
		root:   root,
		bare:   filepath.Join(root, "origin.git"),
		srcDir: filepath.Join(root, "src", "repo"),
		wtRoot: filepath.Join(root, "worktrees"),
	}
	if err := os.MkdirAll(filepath.Join(root, "src"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.MkdirAll(f.wtRoot, 0o755); err != nil {
		t.Fatal(err)
	}
	git(t, root, "init", "--bare", "-b", "main", f.bare)

	seed := filepath.Join(root, "seed")
	git(t, root, "init", "-b", "main", seed)
	identity(t, seed)
	writeCommit(t, seed, "README.md", "hi\n", "init")
	git(t, seed, "remote", "add", "origin", f.bare)
	git(t, seed, "push", "-u", "origin", "main")

	git(t, filepath.Join(root, "src"), "clone", f.bare, f.srcDir)
	identity(t, f.srcDir)

	t.Setenv("AGENTWS_ROOT", f.wtRoot)
	t.Setenv("AGENTWS_SRC_ROOT", filepath.Join(root, "src"))
	t.Setenv("AGENTWS_OWNER", "unkin")
	return f
}

func identity(t *testing.T, dir string) {
	t.Helper()
	git(t, dir, "config", "user.email", "test@example.com")
	git(t, dir, "config", "user.name", "Test")
}

func writeCommit(t *testing.T, dir, name, content, msg string) {
	t.Helper()
	if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}
	git(t, dir, "add", ".")
	git(t, dir, "commit", "-m", msg)
}

// addWorktree creates a managed worktree for branch and returns its path.
func (f *fixture) addWorktree(t *testing.T, branch string) string {
	t.Helper()
	path := filepath.Join(f.wtRoot, agent.WorktreeDirName("repo", branch))
	git(t, f.srcDir, "worktree", "add", path, "-b", branch, "origin/main")
	identity(t, path)
	return path
}

// landUpstream commits content on origin's main, mimicking a squash merge: the
// same patch arrives upstream under a different SHA.
func (f *fixture) landUpstream(t *testing.T, name, content, msg string) {
	t.Helper()
	seed := filepath.Join(f.root, "seed")
	git(t, seed, "pull", "--ff-only", "origin", "main")
	writeCommit(t, seed, name, content, msg)
	git(t, seed, "push", "origin", "main")
}

// fakeGitea serves the pulls listing for unkin/repo with the given PR bodies.
func fakeGitea(t *testing.T, prs ...map[string]any) *httptest.Server {
	t.Helper()
	mux := http.NewServeMux()
	mux.HandleFunc("/api/v1/repos/unkin/repo/pulls", func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Query().Get("page") != "1" {
			_, _ = w.Write([]byte("[]"))
			return
		}
		body, err := json.Marshal(prs)
		if err != nil {
			t.Errorf("marshal PRs: %v", err)
		}
		_, _ = w.Write(body)
	})
	srv := httptest.NewServer(mux)
	t.Cleanup(srv.Close)
	return srv
}

func client(srv *httptest.Server) prLister {
	return &agent.GiteaClient{BaseURL: srv.URL, HTTP: srv.Client()}
}

// mergedPR mimics Gitea after a merge: the branch is deleted, so head.ref
// becomes refs/pull/<n>/head and only head.label still names the branch.
func mergedPR(number int, branch string) map[string]any {
	return map[string]any{
		"number": number,
		"state":  "closed",
		"merged": true,
		"head": map[string]any{
			"ref":   "refs/pull/" + strconv.Itoa(number) + "/head",
			"label": branch,
		},
	}
}

func withHeadSha(pr map[string]any, sha string) map[string]any {
	pr["head"].(map[string]any)["sha"] = sha
	return pr
}

func openPR(number int, branch string) map[string]any {
	return map[string]any{
		"number": number,
		"state":  "open",
		"merged": false,
		"head":   map[string]any{"ref": branch, "label": branch},
	}
}

func closedPR(number int, branch string) map[string]any {
	return map[string]any{
		"number": number,
		"state":  "closed",
		"merged": false,
		"head":   map[string]any{"ref": branch, "label": branch},
	}
}

func run(t *testing.T, prs prLister, apply, keepBranches bool) string {
	t.Helper()
	return runOpts(t, prs, pruneOpts{apply: apply, keepBranches: keepBranches})
}

func runOpts(t *testing.T, prs prLister, opts pruneOpts) string {
	t.Helper()
	var out, errOut bytes.Buffer
	if err := runPrune(&out, &errOut, prs, opts); err != nil {
		t.Fatalf("runPrune: %v\n%s%s", err, out.String(), errOut.String())
	}
	return out.String() + errOut.String()
}

func lineFor(t *testing.T, out, branch string) string {
	t.Helper()
	for _, line := range strings.Split(out, "\n") {
		if fields := strings.Fields(line); len(fields) > 1 && fields[1] == branch {
			return line
		}
	}
	t.Fatalf("no line for branch %q in:\n%s", branch, out)
	return ""
}

// assertVerdict reads the table row for a branch: REPO BRANCH PATH VERDICT REASON.
func assertVerdict(t *testing.T, out, branch, verdict, reason string) {
	t.Helper()
	line := lineFor(t, out, branch)
	fields := strings.Fields(line)
	if len(fields) < 4 || fields[3] != verdict {
		t.Errorf("branch %s: verdict line %q, want verdict %q", branch, line, verdict)
	}
	if reason != "" && !strings.Contains(line, reason) {
		t.Errorf("branch %s: line %q, want reason containing %q", branch, line, reason)
	}
}

func exists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

// A merged PR's branch is deleted on merge, so its head.ref reads
// refs/pull/<n>/head; classification must still see the merge (via head.label)
// and remove the branch, not fall through to "no PR".
func TestPruneMergedPRWithDeletedBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/merged")
	writeCommit(t, wt, "m.txt", "m\n", "work")
	head := git(t, wt, "rev-parse", "HEAD")

	srv := fakeGitea(t, withHeadSha(mergedPR(3, "benvin/merged"), head))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/merged", verdictRemoveBranch, "PR merged #3")

	if exists(wt) {
		t.Errorf("worktree %s should have been removed", wt)
	}
	if agent.GitBranchExists(f.srcDir, "benvin/merged") {
		t.Error("branch of a merged PR should be deleted")
	}
}

// The same PR without head.label: matching falls back to head.ref, which no
// longer names the branch, so prune must not guess it is merged — the worktree
// goes but the branch stays.
func TestPruneMergedPRWithoutLabelKeepsBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/merged")
	writeCommit(t, wt, "m.txt", "m\n", "work")

	pr := mergedPR(3, "benvin/merged")
	pr["head"].(map[string]any)["label"] = ""
	srv := fakeGitea(t, pr)
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/merged", verdictRemove, "no PR")

	if !agent.GitBranchExists(f.srcDir, "benvin/merged") {
		t.Error("branch must survive when the PR could not be matched")
	}
}

func TestPruneContainedBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/contained")

	srv := fakeGitea(t)
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/contained", verdictRemoveBranch, "contained in origin/main")

	if exists(wt) {
		t.Error("contained worktree should have been removed")
	}
	if agent.GitBranchExists(f.srcDir, "benvin/contained") {
		t.Error("contained branch should be deleted")
	}
}

// Squash-merged work keeps a local SHA that is not upstream, so only the
// patch-equivalence check proves it landed.
func TestPruneCherryCleanBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/squashed")
	writeCommit(t, wt, "s.txt", "same\n", "add s")
	f.landUpstream(t, "s.txt", "same\n", "squashed s")

	srv := fakeGitea(t)
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/squashed", verdictRemoveBranch, "patch-equivalent commits in origin/main history")

	if agent.GitBranchExists(f.srcDir, "benvin/squashed") {
		t.Error("cherry-clean branch should be deleted")
	}
}

// Uncommitted work outranks every other signal, including a branch that is
// otherwise fully contained upstream.
func TestPruneNeverTouchesDirtyWorktree(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/dirty")
	if err := os.WriteFile(filepath.Join(wt, "wip.txt"), []byte("wip\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t, mergedPR(4, "benvin/dirty"))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/dirty", verdictKeep, "dirty")

	if !exists(wt) {
		t.Error("dirty worktree must not be removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/dirty") {
		t.Error("dirty worktree's branch must survive")
	}
}

// An open PR is kept even when its commits are already upstream.
func TestPruneKeepsOpenPR(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/open")

	srv := fakeGitea(t, openPR(5, "benvin/open"))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/open", verdictKeep, "PR open #5")

	if !exists(wt) {
		t.Error("worktree with an open PR must not be removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/open") {
		t.Error("branch with an open PR must not be deleted")
	}
}

// Closed-unmerged with the branch still on origin: the work is not lost, so the
// local branch goes too.
func TestPruneClosedPRWithBranchOnOrigin(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/closed")
	writeCommit(t, wt, "c.txt", "c\n", "work")
	git(t, wt, "push", "origin", "benvin/closed")

	srv := fakeGitea(t, closedPR(6, "benvin/closed"))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/closed", verdictRemoveBranch, "PR closed #6, HEAD contained in origin/benvin/closed")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if agent.GitBranchExists(f.srcDir, "benvin/closed") {
		t.Error("branch should be deleted while origin still has it")
	}
}

// Closed-unmerged with nothing on origin: the commits exist only here, so the
// branch is kept and only the worktree goes.
func TestPruneClosedPRWithBranchGone(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/orphan")
	writeCommit(t, wt, "o.txt", "o\n", "work")

	srv := fakeGitea(t, closedPR(7, "benvin/orphan"))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/orphan", verdictRemove, "PR closed #7, branch gone")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/orphan") {
		t.Error("branch must survive when origin does not have the commits")
	}
}

func TestPruneNoPRKeepsBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/unpushed")
	writeCommit(t, wt, "u.txt", "u\n", "work")

	srv := fakeGitea(t)
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/unpushed", verdictRemove, "no PR")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/unpushed") {
		t.Error("branch with unproven work must survive")
	}
}

// The default run reports and changes nothing.
func TestPruneDryRunChangesNothing(t *testing.T) {
	f := newFixture(t)
	contained := f.addWorktree(t, "benvin/contained")
	merged := f.addWorktree(t, "benvin/merged")
	writeCommit(t, merged, "m.txt", "m\n", "work")
	head := git(t, merged, "rev-parse", "HEAD")

	srv := fakeGitea(t, withHeadSha(mergedPR(8, "benvin/merged"), head))
	out := run(t, client(srv), false, false)

	if !strings.Contains(out, "dry run") {
		t.Errorf("dry-run output should say so:\n%s", out)
	}
	assertVerdict(t, out, "benvin/contained", verdictRemoveBranch, "contained")
	assertVerdict(t, out, "benvin/merged", verdictRemoveBranch, "PR merged #8")
	if !exists(contained) || !exists(merged) {
		t.Error("dry run must not remove worktrees")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/contained") || !agent.GitBranchExists(f.srcDir, "benvin/merged") {
		t.Error("dry run must not delete branches")
	}
}

// --keep-branches removes worktrees but leaves every branch alone, and the
// printed verdict says so.
func TestPruneKeepBranches(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/contained")

	srv := fakeGitea(t)
	out := run(t, client(srv), true, true)
	assertVerdict(t, out, "benvin/contained", verdictRemove, "contained")
	if strings.Contains(out, verdictRemoveBranch) {
		t.Errorf("--keep-branches must not print a branch-deleting verdict:\n%s", out)
	}

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/contained") {
		t.Error("--keep-branches must not delete the branch")
	}
}

// With Gitea unreachable prune falls back to the git signals: provably-upstream
// work is still cleaned up, and anything unproven keeps its branch.
func TestPruneDegradesWhenGiteaUnreachable(t *testing.T) {
	f := newFixture(t)
	contained := f.addWorktree(t, "benvin/contained")
	unproven := f.addWorktree(t, "benvin/unproven")
	writeCommit(t, unproven, "u.txt", "u\n", "work")

	dead := httptest.NewServer(http.NewServeMux())
	c := &agent.GiteaClient{BaseURL: dead.URL, HTTP: dead.Client()}
	dead.Close()

	out := run(t, c, true, false)
	if !strings.Contains(out, "git signals only") {
		t.Errorf("output should note the Gitea failure:\n%s", out)
	}
	assertVerdict(t, out, "benvin/contained", verdictRemoveBranch, "contained")
	assertVerdict(t, out, "benvin/unproven", verdictRemove, "PR state unknown")

	if exists(contained) || exists(unproven) {
		t.Error("both worktrees should have been removed")
	}
	if agent.GitBranchExists(f.srcDir, "benvin/contained") {
		t.Error("contained branch is safe to delete without Gitea")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/unproven") {
		t.Error("unproven branch must survive an unreachable Gitea")
	}
}

func TestPruneNoWorktrees(t *testing.T) {
	newFixture(t)
	srv := fakeGitea(t)
	if out := run(t, client(srv), true, false); !strings.Contains(out, "no managed worktrees") {
		t.Errorf("output = %q", out)
	}
}

// Commits made after the PR merged exist nowhere else, so a merged PR alone
// must not authorise deleting the branch.
func TestPruneMergedPRWithCommitsAfterMerge(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/ahead")
	writeCommit(t, wt, "a.txt", "a\n", "merged work")
	merged := git(t, wt, "rev-parse", "HEAD")
	writeCommit(t, wt, "b.txt", "b\n", "work after the merge")

	srv := fakeGitea(t, withHeadSha(mergedPR(9, "benvin/ahead"), merged))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/ahead", verdictRemove, "PR merged #9")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/ahead") {
		t.Error("branch with commits beyond the merged head must survive")
	}
}

// HEAD proven contained in the merged head still loses its branch.
func TestPruneMergedPRContainedInMergedHead(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/landed")
	writeCommit(t, wt, "a.txt", "a\n", "work")
	head := git(t, wt, "rev-parse", "HEAD")

	srv := fakeGitea(t, withHeadSha(mergedPR(10, "benvin/landed"), head))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/landed", verdictRemoveBranch, "HEAD contained in the merged head")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if agent.GitBranchExists(f.srcDir, "benvin/landed") {
		t.Error("branch contained in the merged head should be deleted")
	}
}

// A surviving remote branch only covers what was pushed to it; later local
// commits keep the branch.
func TestPruneClosedPRWithCommitsBeyondOrigin(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/beyond")
	writeCommit(t, wt, "c.txt", "c\n", "pushed work")
	git(t, wt, "push", "origin", "benvin/beyond")
	writeCommit(t, wt, "d.txt", "d\n", "local only")

	srv := fakeGitea(t, closedPR(11, "benvin/beyond"))
	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/beyond", verdictRemove, "local commits not on origin/benvin/beyond")

	if exists(wt) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/beyond") {
		t.Error("branch with commits beyond origin must survive")
	}
}

// truncatedLister stands in for a repo with more PRs than the listing cap.
type truncatedLister struct{ prs []agent.PullRequest }

func (l truncatedLister) ListPRs(string, string) ([]agent.PullRequest, error) {
	return l.prs, fmt.Errorf("unkin/repo: %w after 1000 pull requests", agent.ErrPRListTruncated)
}

// A truncated listing still classifies the PRs it saw, but a branch missing
// from it reads as unknown rather than as having no PR.
func TestPruneWarnsOnTruncatedPRListing(t *testing.T) {
	f := newFixture(t)
	listed := f.addWorktree(t, "benvin/listed")
	writeCommit(t, listed, "a.txt", "a\n", "work")
	head := git(t, listed, "rev-parse", "HEAD")
	unlisted := f.addWorktree(t, "benvin/unlisted")
	writeCommit(t, unlisted, "b.txt", "b\n", "work")

	var pr agent.PullRequest
	pr.Number, pr.State, pr.Merged = 12, "closed", true
	pr.Head.Label, pr.Head.Sha = "benvin/listed", head

	out := run(t, truncatedLister{prs: []agent.PullRequest{pr}}, true, false)
	if !strings.Contains(out, "truncated") || !strings.Contains(out, "older PRs unseen") {
		t.Errorf("output should warn about the truncated listing:\n%s", out)
	}
	assertVerdict(t, out, "benvin/listed", verdictRemoveBranch, "PR merged #12")
	assertVerdict(t, out, "benvin/unlisted", verdictRemove, "PR state unknown")

	if agent.GitBranchExists(f.srcDir, "benvin/listed") {
		t.Error("branch of a merged PR seen in the listing should be deleted")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/unlisted") {
		t.Error("branch missing from a truncated listing must survive")
	}
}

// breakRemote points origin at a path that does not exist, so every fetch fails.
func (f *fixture) breakRemote(t *testing.T) {
	t.Helper()
	git(t, f.srcDir, "remote", "set-url", "origin", filepath.Join(f.root, "missing.git"))
}

// applyUnreachable applies the plan against a repo whose remote is unreachable.
// The post-removal refresh fetch fails, so runPrune must report an error; the
// classification and the removals it authorised happen regardless.
func applyUnreachable(t *testing.T, prs prLister) string {
	t.Helper()
	var out, errOut bytes.Buffer
	err := runPrune(&out, &errOut, prs, pruneOpts{apply: true})
	if err == nil {
		t.Fatalf("expected the refresh fetch to fail against a missing remote:\n%s", out.String())
	}
	return out.String() + errOut.String()
}

// staleFixture builds a repo where origin/<branch> covers HEAD for a closed and
// a merged PR. Deleting the branches on origin makes those tracking refs stale:
// a pruning fetch would drop them, so they only prove anything while a fetch
// this run confirms they are still there.
func staleFixture(t *testing.T, deleteUpstream bool) (*fixture, *httptest.Server, string, string) {
	t.Helper()
	f := newFixture(t)
	closed := f.addWorktree(t, "benvin/stale-closed")
	writeCommit(t, closed, "c.txt", "c\n", "work")
	git(t, closed, "push", "origin", "benvin/stale-closed")

	merged := f.addWorktree(t, "benvin/stale-merged")
	writeCommit(t, merged, "m.txt", "m\n", "work")
	git(t, merged, "push", "origin", "benvin/stale-merged")

	if deleteUpstream {
		git(t, f.bare, "update-ref", "-d", "refs/heads/benvin/stale-closed")
		git(t, f.bare, "update-ref", "-d", "refs/heads/benvin/stale-merged")
	}

	// The merged head is an older commit, so only origin/<branch> covers HEAD.
	base := git(t, f.srcDir, "rev-parse", "origin/main")
	srv := fakeGitea(t,
		closedPR(20, "benvin/stale-closed"),
		withHeadSha(mergedPR(21, "benvin/stale-merged"), base),
	)
	return f, srv, closed, merged
}

// A tracking ref this run's fetch could not confirm is not evidence: the branch
// may already be gone upstream, and the next successful --prune deletes the ref.
// Both worktrees go, both branches stay.
func TestPruneFailedFetchDistrustsStaleRemoteBranch(t *testing.T) {
	f, srv, closed, merged := staleFixture(t, true)
	f.breakRemote(t)

	out := run(t, client(srv), false, false)
	if !strings.Contains(out, "remote state unverified") {
		t.Errorf("output should report the failed fetch:\n%s", out)
	}
	assertVerdict(t, out, "benvin/stale-closed", verdictRemove, "PR closed #20, fetch failed so origin/benvin/stale-closed is unverified")
	assertVerdict(t, out, "benvin/stale-merged", verdictRemove, "PR merged #21, fetch failed so origin/benvin/stale-merged is unverified")
	for _, b := range []string{"benvin/stale-closed", "benvin/stale-merged"} {
		if !agent.GitRemoteBranchExists(f.srcDir, "origin", b) {
			t.Fatalf("fixture: origin/%s should still be present as a stale ref", b)
		}
	}

	applyUnreachable(t, client(srv))
	if exists(closed) || exists(merged) {
		t.Error("both worktrees should have been removed")
	}
	for _, b := range []string{"benvin/stale-closed", "benvin/stale-merged"} {
		if !agent.GitBranchExists(f.srcDir, b) {
			t.Errorf("branch %s must survive an unverified origin", b)
		}
	}
}

// The control for the case above: with the fetch working and the branches still
// on origin, the same shape still loses both branches.
func TestPruneSuccessfulFetchTrustsRemoteBranch(t *testing.T) {
	f, srv, closed, merged := staleFixture(t, false)

	out := run(t, client(srv), true, false)
	assertVerdict(t, out, "benvin/stale-closed", verdictRemoveBranch, "PR closed #20, HEAD contained in origin/benvin/stale-closed")
	assertVerdict(t, out, "benvin/stale-merged", verdictRemoveBranch, "PR merged #21, HEAD contained in origin/benvin/stale-merged")

	if exists(closed) || exists(merged) {
		t.Error("both worktrees should have been removed")
	}
	for _, b := range []string{"benvin/stale-closed", "benvin/stale-merged"} {
		if agent.GitBranchExists(f.srcDir, b) {
			t.Errorf("branch %s should be deleted while origin still has it", b)
		}
	}
}

// Proofs that read only local objects and the merged head SHA from the API do
// not depend on the fetch, so a failed fetch must not suppress them.
func TestPruneFailedFetchKeepsFetchIndependentProofs(t *testing.T) {
	f := newFixture(t)
	contained := f.addWorktree(t, "benvin/contained")
	landed := f.addWorktree(t, "benvin/landed")
	writeCommit(t, landed, "a.txt", "a\n", "work")
	head := git(t, landed, "rev-parse", "HEAD")
	f.breakRemote(t)

	srv := fakeGitea(t, withHeadSha(mergedPR(22, "benvin/landed"), head))
	out := applyUnreachable(t, client(srv))
	assertVerdict(t, out, "benvin/contained", verdictRemoveBranch, "contained in origin/main")
	assertVerdict(t, out, "benvin/landed", verdictRemoveBranch, "PR merged #22, HEAD contained in the merged head")

	if exists(contained) || exists(landed) {
		t.Error("both worktrees should have been removed")
	}
	for _, b := range []string{"benvin/contained", "benvin/landed"} {
		if agent.GitBranchExists(f.srcDir, b) {
			t.Errorf("branch %s is proven without the fetch and should be deleted", b)
		}
	}
}

// Managed repos are not all under AGENTWS_OWNER, so the Gitea path comes from
// origin's URL; a non-Gitea remote falls back to the configured owner.
func TestRepoPathFollowsOrigin(t *testing.T) {
	t.Setenv("AGENTWS_OWNER", "unkin")
	dir := t.TempDir()
	git(t, dir, "init", "-b", "main", ".")
	git(t, dir, "remote", "add", "origin", "https://git.unkin.net/unkinben/dotfiles.git")
	if got := repoPath(dir, "dotfiles"); got != "unkinben/dotfiles" {
		t.Errorf("repoPath = %q, want unkinben/dotfiles", got)
	}
	git(t, dir, "remote", "set-url", "origin", filepath.Join(dir, "origin.git"))
	if got := repoPath(dir, "dotfiles"); got != "unkin/dotfiles" {
		t.Errorf("repoPath for a local remote = %q, want unkin/dotfiles", got)
	}
}

// --- discovery beyond the worktree root -----------------------------------

// gitAllow runs git and returns its combined output without failing the test,
// for commands that are expected to stop mid-way (e.g. an interrupted rebase).
func gitAllow(t *testing.T, dir string, args ...string) string {
	t.Helper()
	cmd := exec.Command("git", args...)
	cmd.Dir = dir
	out, _ := cmd.CombinedOutput()
	return strings.TrimSpace(string(out))
}

// addManualWorktree creates a worktree outside the worktree root, the way a
// person would by hand, so only `git worktree list` can find it.
func (f *fixture) addManualWorktree(t *testing.T, branch string) string {
	t.Helper()
	path := filepath.Join(f.root, "manual", agent.SanitizeBranch(branch))
	git(t, f.srcDir, "worktree", "add", path, "-b", branch, "origin/main")
	identity(t, path)
	return path
}

// A hand-made worktree outside the worktree root is still classified, but the
// default run refuses to remove it: that needs --include-unmanaged.
func TestPruneReportsUnmanagedWorktreeButKeepsIt(t *testing.T) {
	f := newFixture(t)
	manual := f.addManualWorktree(t, "benvin/by-hand")

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "benvin/by-hand", verdictRemoveBranch, "contained in origin/main")
	if !strings.Contains(out, "--include-unmanaged") {
		t.Errorf("output should name the flag that would remove it:\n%s", out)
	}
	if !exists(manual) {
		t.Error("an unmanaged worktree must survive without --include-unmanaged")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/by-hand") {
		t.Error("an unmanaged worktree's branch must survive too")
	}
}

func TestPruneRemovesUnmanagedWorktreeWithFlag(t *testing.T) {
	f := newFixture(t)
	manual := f.addManualWorktree(t, "benvin/by-hand")

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true, includeUnmanaged: true})
	assertVerdict(t, out, "benvin/by-hand", verdictRemoveBranch, "contained in origin/main")
	if exists(manual) {
		t.Error("--include-unmanaged should have removed the worktree")
	}
}

// --include-unmanaged only lifts the location gate. A keep verdict is a separate
// gate, so a dirty hand-made worktree still needs --include-keep to be touched.
func TestPruneIncludeUnmanagedStillObeysKeep(t *testing.T) {
	f := newFixture(t)
	manual := f.addManualWorktree(t, "benvin/by-hand")
	if err := os.WriteFile(filepath.Join(manual, "scratch.txt"), []byte("wip\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true, includeUnmanaged: true})
	assertVerdict(t, out, "benvin/by-hand", verdictKeep, "dirty")
	if !exists(filepath.Join(manual, "scratch.txt")) {
		t.Error("--include-unmanaged must not remove a worktree classified keep")
	}
}

// A worktree whose directory was deleted leaves only a registration behind:
// there is nothing to lose, so it is prunable outright.
func TestPruneStaleRegistrationWithMissingDirectory(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/vanished")
	writeCommit(t, wt, "v.txt", "v\n", "work")
	if err := os.RemoveAll(wt); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "benvin/vanished", verdictRemove, "working tree gone")

	wts, err := agent.GitWorktreeList(f.srcDir)
	if err != nil {
		t.Fatal(err)
	}
	for _, w := range wts {
		if w.Path == wt {
			t.Errorf("registration for %s should have been pruned: %+v", wt, w)
		}
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/vanished") {
		t.Error("pruning a registration must not delete the branch")
	}
}

// A directory under the worktree root whose backing repo is gone cannot be
// inspected by git at all, so prune deletes the leftover directory.
func TestPruneOrphanedDirectoryWhenRepoIsGone(t *testing.T) {
	f := newFixture(t)
	other := filepath.Join(f.root, "src", "other")
	git(t, filepath.Join(f.root, "src"), "clone", f.bare, other)
	identity(t, other)
	orphan := filepath.Join(f.wtRoot, agent.WorktreeDirName("other", "benvin/orphaned"))
	git(t, other, "worktree", "add", orphan, "-b", "benvin/orphaned", "origin/main")
	if err := os.RemoveAll(other); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "-", verdictRemove, "backing repo gone")
	if exists(orphan) {
		t.Error("an orphaned worktree directory should have been deleted")
	}
}

// addForeignWorktree clones a second repo under the source root and gives it a
// worktree under the worktree root, so it can be broken without touching the
// fixture's own repo. It returns the clone and the worktree path.
func (f *fixture) addForeignWorktree(t *testing.T, repo, branch string) (string, string) {
	t.Helper()
	src := filepath.Join(f.root, "src", repo)
	git(t, filepath.Join(f.root, "src"), "clone", f.bare, src)
	identity(t, src)
	wt := filepath.Join(f.wtRoot, agent.WorktreeDirName(repo, branch))
	git(t, src, "worktree", "add", wt, "-b", branch, "origin/main")
	return src, wt
}

// The regression this guards: git failing for a reason that is not "the backing
// repo is gone" used to be read as orphan, and orphan deletes the directory
// outright. Here the git dir is still on disk — only its commondir pointer is
// broken, as a half-written or momentarily unreachable repo would be — so the
// verdict must be keep and the directory must survive a --yes run.
func TestPruneKeepsWorktreeWhenGitFailsButRepoExists(t *testing.T) {
	f := newFixture(t)
	src, wt := f.addForeignWorktree(t, "other", "benvin/unreadable")
	writeCommit(t, wt, "u.txt", "u\n", "work")
	gitDir, err := agent.GitDir(wt)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.Remove(filepath.Join(gitDir, "commondir")); err != nil {
		t.Fatal(err)
	}
	if _, err := agent.GitCurrentBranch(wt); err == nil {
		t.Fatal("fixture did not break git in the worktree")
	}
	if !exists(gitDir) || !exists(filepath.Join(src, ".git")) {
		t.Fatal("fixture removed the backing repo; it must still be present")
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "-", verdictKeep, "inspection failed")
	if !exists(wt) {
		t.Error("a worktree git could not be read must not be deleted")
	}
}

// The same rule one step further in: the registration is gone but the repo is
// not, so the directory is still recoverable and must not be deleted.
func TestPruneKeepsWorktreeWhenOnlyRegistrationIsGone(t *testing.T) {
	f := newFixture(t)
	src, wt := f.addForeignWorktree(t, "other", "benvin/deregistered")
	gitDir, err := agent.GitDir(wt)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.RemoveAll(gitDir); err != nil {
		t.Fatal(err)
	}
	if !exists(filepath.Join(src, ".git")) {
		t.Fatal("fixture removed the backing repo; it must still be present")
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "-", verdictKeep, "inspection failed")
	if !exists(wt) {
		t.Error("a worktree whose repo still exists must not be deleted")
	}
}

// --include-keep overrides a keep, but it must not become a second route to the
// deletion finding #1 closed: with no readable git state there is nothing to
// remove through, so the removal fails loudly and the directory stays.
func TestPruneIncludeKeepDoesNotDeleteUnreadableWorktree(t *testing.T) {
	f := newFixture(t)
	_, wt := f.addForeignWorktree(t, "other", "benvin/forced")
	gitDir, err := agent.GitDir(wt)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.Remove(filepath.Join(gitDir, "commondir")); err != nil {
		t.Fatal(err)
	}

	var out, errOut bytes.Buffer
	err = runPrune(&out, &errOut, client(fakeGitea(t)), pruneOpts{apply: true, includeKeep: true})
	if err == nil {
		t.Error("forcing removal of an unreadable worktree should fail, not succeed silently")
	}
	if !exists(wt) {
		t.Error("--include-keep must not delete a worktree whose git state is unknown")
	}
}

// --- safety signals -------------------------------------------------------

// An interrupted rebase holds sequencer state that exists nowhere else, and it
// detaches HEAD while it runs, so it must outrank every other signal.
func TestPruneKeepsInterruptedRebase(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/rebasing")
	writeCommit(t, wt, "r.txt", "r\n", "work")
	gitAllow(t, wt, "rebase", "--exec", "false", "origin/main")
	if op, err := agent.GitInProgressOp(wt); err != nil || op != "rebase" {
		t.Fatalf("fixture did not leave a rebase in progress: op=%q err=%v", op, err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "HEAD", verdictKeep, "rebase in progress")
	if !exists(wt) {
		t.Error("a worktree mid-rebase must not be removed")
	}
}

// A half-finished cherry-pick is the same case with a branch still checked out,
// so the sequencer check has to run before the dirty check can mask it.
func TestPruneKeepsInterruptedCherryPick(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/picking")
	gitDir, err := agent.GitDir(wt)
	if err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(gitDir, "CHERRY_PICK_HEAD"), []byte(git(t, wt, "rev-parse", "HEAD")+"\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "benvin/picking", verdictKeep, "cherry-pick in progress")
	if !exists(wt) {
		t.Error("a worktree mid-cherry-pick must not be removed")
	}
}

// A detached HEAD has no branch to carry its commits, so unique work there is
// unrecoverable once the worktree goes.
func TestPruneKeepsDetachedHeadWithUniqueCommits(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/detaching")
	writeCommit(t, wt, "d.txt", "d\n", "work")
	git(t, wt, "checkout", "--detach")
	git(t, f.srcDir, "branch", "-D", "benvin/detaching")

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "HEAD", verdictKeep, "detached HEAD carrying 1 commit on no remote")
	if !exists(wt) {
		t.Error("a detached worktree with unique commits must not be removed")
	}
}

// A detached HEAD whose commit is already upstream is safe to drop, but there is
// no branch to delete, so the verdict must not promise one.
func TestPruneDetachedHeadContainedUpstream(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/detached-clean")
	git(t, wt, "checkout", "--detach")
	git(t, f.srcDir, "branch", "-D", "benvin/detached-clean")

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "HEAD", verdictRemove, "contained in origin/main")
	if strings.Contains(out, verdictRemoveBranch) {
		t.Errorf("a detached worktree has no branch to delete:\n%s", out)
	}
	if exists(wt) {
		t.Error("a detached worktree contained upstream should have been removed")
	}
}

// git refuses to drop a locked worktree, and so does prune.
func TestPruneKeepsLockedWorktree(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/locked")
	git(t, f.srcDir, "worktree", "lock", wt)

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true})
	assertVerdict(t, out, "benvin/locked", verdictKeep, "locked")
	if !exists(wt) {
		t.Error("a locked worktree must not be removed")
	}
}

// Unproven work is only safe to abandon because the branch keeps it, so the
// reason has to say so rather than leaving the operator to guess.
func TestPruneReasonNamesRetainedBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/unpushed")
	writeCommit(t, wt, "u.txt", "u\n", "work")

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{})
	assertVerdict(t, out, "benvin/unpushed", verdictRemove, "1 commit on no remote so branch benvin/unpushed is kept")
	if !exists(wt) {
		t.Error("a dry run must not remove anything")
	}
}

// --- flags ----------------------------------------------------------------

// --include-keep is the only way past a keep verdict, and even then the branch
// stays, so the commits survive the worktree.
func TestPruneIncludeKeepRemovesDirtyWorktreeButNotItsBranch(t *testing.T) {
	f := newFixture(t)
	wt := f.addWorktree(t, "benvin/dirty")
	writeCommit(t, wt, "d.txt", "d\n", "work")
	if err := os.WriteFile(filepath.Join(wt, "wip.txt"), []byte("wip\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{apply: true, includeKeep: true})
	assertVerdict(t, out, "benvin/dirty", verdictKeep, "dirty")
	if !strings.Contains(out, "--include-keep") {
		t.Errorf("forcing a keep should warn it is doing so:\n%s", out)
	}
	if exists(wt) {
		t.Error("--include-keep should have removed the dirty worktree")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/dirty") {
		t.Error("--include-keep must never delete a branch")
	}
}

// --no-fetch means origin's refs are whatever is already on disk, so a tracking
// ref cannot prove the work survives: the branch is kept.
func TestPruneNoFetchDistrustsTrackingRefs(t *testing.T) {
	f, srv, closed, _ := staleFixture(t, true)

	out := runOpts(t, client(srv), pruneOpts{apply: true, noFetch: true})
	if !strings.Contains(out, "--no-fetch") {
		t.Errorf("output should record that the fetch was skipped:\n%s", out)
	}
	assertVerdict(t, out, "benvin/stale-closed", verdictRemove, "is unverified")
	if exists(closed) {
		t.Error("worktree should have been removed")
	}
	if !agent.GitBranchExists(f.srcDir, "benvin/stale-closed") {
		t.Error("an unverified tracking ref must not authorise deleting the branch")
	}
}

// --json puts the machine-readable document on stdout alone, with the same
// verdicts the table shows.
func TestPruneJSONOutput(t *testing.T) {
	f := newFixture(t)
	contained := f.addWorktree(t, "benvin/contained")
	dirty := f.addWorktree(t, "benvin/dirty")
	if err := os.WriteFile(filepath.Join(dirty, "wip.txt"), []byte("wip\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	srv := fakeGitea(t)
	var out, errOut bytes.Buffer
	if err := runPrune(&out, &errOut, client(srv), pruneOpts{jsonOut: true}); err != nil {
		t.Fatalf("runPrune: %v", err)
	}
	var entries []reportEntry
	if err := json.Unmarshal(out.Bytes(), &entries); err != nil {
		t.Fatalf("stdout is not JSON (%v): %s", err, out.String())
	}
	byBranch := map[string]reportEntry{}
	for _, e := range entries {
		byBranch[e.Branch] = e
	}
	if got := byBranch["benvin/contained"]; got.Verdict != verdictRemoveBranch || got.Path != contained || !got.Managed || got.Applied {
		t.Errorf("contained entry = %+v", got)
	}
	if got := byBranch["benvin/dirty"]; got.Verdict != verdictKeep || got.Reason != "dirty" {
		t.Errorf("dirty entry = %+v", got)
	}
	if !exists(contained) {
		t.Error("a --json dry run must not remove anything")
	}
	_ = f
}

// A directory in the source root can itself be a linked worktree. Enumerating
// from there lists the repo's real checkout, which must never be offered up for
// removal — discovery normalises each candidate to its main checkout instead.
func TestPruneNeverOffersAMainCheckout(t *testing.T) {
	f := newFixture(t)
	sibling := filepath.Join(f.root, "src", "repo-sibling")
	git(t, f.srcDir, "worktree", "add", sibling, "-b", "benvin/sibling", "origin/main")
	identity(t, sibling)

	srv := fakeGitea(t)
	out := runOpts(t, client(srv), pruneOpts{})
	for _, line := range strings.Split(out, "\n") {
		if fields := strings.Fields(line); len(fields) > 2 && fields[2] == f.srcDir {
			t.Errorf("main checkout %s must not be classified: %q", f.srcDir, line)
		}
	}
	assertVerdict(t, out, "benvin/sibling", verdictRemoveBranch, "contained in origin/main")
	if strings.Contains(out, "\tmain\t") || lineForBranch(out, "main") != "" {
		t.Errorf("the default branch's own checkout must not appear:\n%s", out)
	}
}

// lineForBranch is lineFor without the fatal, for asserting a row is absent.
func lineForBranch(out, branch string) string {
	for _, line := range strings.Split(out, "\n") {
		if fields := strings.Fields(line); len(fields) > 1 && fields[1] == branch {
			return line
		}
	}
	return ""
}