package herdr

import (
	"bufio"
	"context"
	"encoding/json"
	"net"
	"orchestra/internal/continuity"
	"os"
	"os/exec"
	"path/filepath"
	"testing"
)

type memCAS struct{ m map[string][]byte }

func (c *memCAS) PutArtifact(b []byte) (string, error) {
	if c.m == nil {
		c.m = map[string][]byte{}
	}
	id := string(rune(len(c.m) + 'a'))
	c.m[id] = b
	return id, nil
}
func (c *memCAS) Artifact(ref string) ([]byte, error) { return c.m[ref], nil }

func runGit(t *testing.T, dir string, args ...string) {
	t.Helper()
	cmd := exec.Command("git", append([]string{"-C", dir}, args...)...)
	if out, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("git %v: %v: %s", args, err, out)
	}
}

// fakeHerdr accepts one JSON-RPC connection and replies with an empty result
// to every request — enough to exercise CLIAdapter.Release's pane.release_agent
// call without a live herdr instance.
func fakeHerdr(t *testing.T) *Client {
	t.Helper()
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { ln.Close() })
	go func() {
		conn, err := ln.Accept()
		if err != nil {
			return
		}
		defer conn.Close()
		var req Request
		if err := json.NewDecoder(bufio.NewReader(conn)).Decode(&req); err != nil {
			return
		}
		json.NewEncoder(conn).Encode(Response{ID: req.ID, Result: json.RawMessage(`{}`)})
	}()
	return &Client{Path: ln.Addr().String(), dial: func() (net.Conn, error) { return net.Dial("tcp", ln.Addr().String()) }}
}

func validHandoff(anchorSHA string) continuity.Handoff {
	return continuity.Handoff{
		Meta:    continuity.Meta{ID: "t1", Reason: "threshold", RotationIndex: 1},
		Anchor:  continuity.Anchor{GitSHA: anchorSHA, Branch: "main"},
		Action:  "run the focused tests",
		Command: "go test ./...",
	}
}

const validAnswer = `NEXT: run the focused tests
WHY: confirm the current implementation before changing it
REMAINING: NONE
DEAD ENDS: NONE
OPEN Q: NONE
LEARNED: NONE`

func TestReleaseUploadsHandoffAndReleasesAgent(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	head, err := HeadSHA(repo)
	if err != nil {
		t.Fatal(err)
	}

	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}

	cas := &memCAS{}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: cas}
	ref, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo})
	if err != nil {
		t.Fatalf("Release: %v", err)
	}
	if ref == "" {
		t.Fatal("expected non-empty handoff ref")
	}
	if _, ok := cas.m[ref]; !ok {
		t.Fatal("handoff was not uploaded to CAS")
	}
	got, err := continuity.Load(ref, cas)
	if err != nil {
		t.Fatal(err)
	}
	if got.Anchor.GitSHA != head {
		t.Fatal("semantic report must not be included in the successor scratch anchor")
	}
	if _, err := os.Stat(filepath.Join(repo, HandoffReportFile)); !os.IsNotExist(err) {
		t.Fatalf("transferred semantic report still present: %v", err)
	}
}

func TestCanonicalHandoffCarriesCoordinatorReason(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}
	cas := &memCAS{}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: cas}
	ref, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo, HandoffReason: "thrash"})
	if err != nil {
		t.Fatal(err)
	}
	got, err := continuity.Load(ref, cas)
	if err != nil {
		t.Fatal(err)
	}
	if got.Meta.Reason != "thrash" {
		t.Fatalf("canonical reason = %q, want thrash", got.Meta.Reason)
	}
}

func TestReleaseUsesHarnessBindingNotDisplayName(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = ln.Close() })
	request := make(chan Request, 1)
	go func() {
		conn, err := ln.Accept()
		if err != nil {
			return
		}
		defer conn.Close()
		var req Request
		if json.NewDecoder(bufio.NewReader(conn)).Decode(&req) == nil {
			request <- req
			_ = json.NewEncoder(conn).Encode(Response{ID: req.ID, Result: json.RawMessage(`{}`)})
		}
	}()
	a := CLIAdapter{Client: &Client{Path: ln.Addr().String(), dial: func() (net.Conn, error) { return net.Dial("tcp", ln.Addr().String()) }}, Harness: "opencode", CAS: &memCAS{}}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo, AgentName: "oc-task-specific"}); err != nil {
		t.Fatal(err)
	}
	req := <-request
	p, _ := json.Marshal(req.Params)
	var got struct {
		Agent string `json:"agent"`
	}
	_ = json.Unmarshal(p, &got)
	if got.Agent != "opencode" {
		t.Fatalf("release agent = %q, want harness binding opencode", got.Agent)
	}
}

func TestReleaseRefusesWithoutHandoffFile(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: &memCAS{}}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo}); err == nil {
		t.Fatal("expected error when no handoff file is present")
	}
}

func TestReleaseRefusesNarrativeOrCircularHandoffAnswer(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	bad := `NEXT: Continue the task from the handoff
WHY: the predecessor asked for it
REMAINING: what changed\n# a markdown report
DEAD ENDS: NONE
OPEN Q: NONE
LEARNED: NONE`
	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(bad), 0o644); err != nil {
		t.Fatal(err)
	}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: &memCAS{}}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo}); err == nil {
		t.Fatal("expected invalid agent answer to refuse release")
	}
}

func TestParseHandoffAnswerPreservesOnlyAuthoredFields(t *testing.T) {
	a, err := parseHandoffAnswer(`NEXT: inspect the failing integration test
WHY: isolate the regression before changing production code
REMAINING: fix the assertion after identifying the cause
DEAD ENDS: tried rerunning the whole suite → failed because it obscures the relevant failure
OPEN Q: whether the remote worker has the updated fixture
LEARNED: the fixture requires a committed scratch branch
`)
	if err != nil {
		t.Fatal(err)
	}
	if len(a.Remaining) != 1 || len(a.DeadEnds) != 1 || len(a.OpenQuestions) != 1 || len(a.Learned) != 1 {
		t.Fatalf("parsed answer lost authored fields: %#v", a)
	}
}

func TestReleaseDoesNotTrustAgentSuppliedAnchor(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")

	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: &memCAS{}}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo}); err != nil {
		t.Fatalf("Release must derive the anchor itself: %v", err)
	}
}

func TestReleaseScratchCommitsDirtyFilesBeforeUpload(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	head, err := HeadSHA(repo)
	if err != nil {
		t.Fatal(err)
	}

	wipPath := filepath.Join(repo, "wip.txt")
	if err := os.WriteFile(wipPath, []byte("in progress"), 0644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}

	cas := &memCAS{}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: cas}
	ref, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo})
	if err != nil {
		t.Fatalf("Release: %v", err)
	}
	got, err := continuity.Load(ref, cas)
	if err != nil {
		t.Fatal(err)
	}
	if got.Anchor.GitSHA == head {
		t.Fatal("expected anchor to advance to the new scratch commit")
	}
	if len(got.Anchor.Dirty) != 0 {
		t.Fatal("expected dirty entries to be cleared after scratch commit")
	}
	newHead, err := HeadSHA(repo)
	if err != nil {
		t.Fatal(err)
	}
	if got.Anchor.GitSHA != newHead {
		t.Fatalf("stored anchor=%s does not match worktree HEAD=%s", got.Anchor.GitSHA, newHead)
	}
	branch, err := exec.Command("git", "-C", repo, "branch", "--show-current").Output()
	if err != nil {
		t.Fatal(err)
	}
	if got.Anchor.Branch != "orchestra/scratch/p1" || string(branch) != got.Anchor.Branch+"\n" {
		t.Fatalf("expected worktree on scratch branch, got %q (handoff says %q)", branch, got.Anchor.Branch)
	}
}

func TestReleaseDoesNotTrustAgentSuppliedDirtyFile(t *testing.T) {
	repo := t.TempDir()
	runGit(t, repo, "init")
	runGit(t, repo, "config", "user.email", "t@t")
	runGit(t, repo, "config", "user.name", "t")
	runGit(t, repo, "commit", "--allow-empty", "-m", "init")
	if err := os.WriteFile(filepath.Join(repo, "wip.txt"), []byte("changed after handoff written"), 0644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(repo, HandoffReportFile), []byte(validAnswer), 0644); err != nil {
		t.Fatal(err)
	}
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude", CAS: &memCAS{}}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: repo}); err != nil {
		t.Fatalf("Release must derive dirty hashes itself: %v", err)
	}
}

func TestReleaseRequiresCAS(t *testing.T) {
	a := CLIAdapter{Client: fakeHerdr(t), Harness: "claude"}
	if _, err := a.Release(context.Background(), Session{PaneID: "p1", Worktree: t.TempDir()}); err == nil {
		t.Fatal("expected error when CAS is nil")
	}
}