package statequality

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"scm.bstein.dev/bstein/ananke/internal/state"
)

// TestStateIntentErrorAndParseBranches runs one orchestration or CLI step.
// Signature: TestStateIntentErrorAndParseBranches(t *testing.T).
// Why: covers non-happy-path intent branches that show up during interrupted drill recovery.
func TestStateIntentErrorAndParseBranches(t *testing.T) {
	root := t.TempDir()

	// ReadIntent should surface non-not-exist read errors.
	if _, err := state.ReadIntent(root); err == nil {
		t.Fatalf("expected read error when intent path is a directory")
	}

	// WriteIntent should fail when parent path cannot be created as a directory.
	parentFile := filepath.Join(root, "parent-file")
	if err := os.WriteFile(parentFile, []byte("x"), 0o600); err != nil {
		t.Fatalf("write parent marker: %v", err)
	}
	if err := state.WriteIntent(filepath.Join(parentFile, "intent.json"), state.Intent{State: state.IntentNormal}); err == nil {
		t.Fatalf("expected write failure when parent is not a directory")
	}

	ts := time.Now().UTC().Truncate(time.Second)
	raw := "prefix text intent=startup_in_progress reason=\"manual\" source=peer updated_at=" + ts.Format(time.RFC3339)
	in, err := state.ParseIntentOutput(raw)
	if err != nil {
		t.Fatalf("parse intent output: %v", err)
	}
	if in.State != state.IntentStartupInProgress || in.Reason != "manual" || in.Source != "peer" || !in.UpdatedAt.Equal(ts) {
		t.Fatalf("unexpected parsed intent: %+v", in)
	}
}

// TestStateStoreLockAndEstimatorBranches runs one orchestration or CLI step.
// Signature: TestStateStoreLockAndEstimatorBranches(t *testing.T).
// Why: exercises stale-lock error handling and estimator filtering behavior.
func TestStateStoreLockAndEstimatorBranches(t *testing.T) {
	root := t.TempDir()

	// AcquireLock should fail when lock parent cannot be created.
	parentFile := filepath.Join(root, "lock-parent")
	if err := os.WriteFile(parentFile, []byte("x"), 0o600); err != nil {
		t.Fatalf("write lock parent marker: %v", err)
	}
	if _, err := state.AcquireLock(filepath.Join(parentFile, "ananke.lock")); err == nil {
		t.Fatalf("expected acquire lock to fail when parent path is a file")
	}

	// AcquireLock should report stale-lock check failure when lock file cannot be read.
	lockDir := filepath.Join(root, "locks")
	if err := os.MkdirAll(lockDir, 0o755); err != nil {
		t.Fatalf("mkdir lock dir: %v", err)
	}
	lockPath := filepath.Join(lockDir, "ananke.lock")
	lockTargetDir := filepath.Join(lockDir, "lock-target")
	if err := os.MkdirAll(lockTargetDir, 0o755); err != nil {
		t.Fatalf("mkdir lock target dir: %v", err)
	}
	if err := os.Symlink(lockTargetDir, lockPath); err != nil {
		t.Fatalf("create lock symlink to directory: %v", err)
	}
	if _, err := state.AcquireLock(lockPath); err == nil || !strings.Contains(err.Error(), "existing lock check failed") {
		t.Fatalf("expected stale lock check failure, got %v", err)
	}

	storePath := filepath.Join(root, "runs.json")
	st := state.New(storePath)
	records := []state.RunRecord{
		{ID: "a", Action: "shutdown", Reason: "ups-threshold alpha", StartedAt: time.Now().Add(-10 * time.Second), EndedAt: time.Now(), DurationSeconds: 40, Success: true},
		{ID: "b", Action: "shutdown", Reason: "UPS-THRESHOLD beta", StartedAt: time.Now().Add(-10 * time.Second), EndedAt: time.Now(), DurationSeconds: 50, Success: true},
	}
	for _, rec := range records {
		if err := st.Append(rec); err != nil {
			t.Fatalf("append record: %v", err)
		}
	}

	if got := st.ShutdownP95WithMinSamples(99, 0); got <= 0 {
		t.Fatalf("expected computed p95 when minSamples<=0 branch is normalized, got %d", got)
	}
	if got := st.ShutdownP95ByReasonPrefix(77, 1, []string{"  ups-threshold  "}); got < 40 {
		t.Fatalf("expected prefix-filtered p95 to include matching records, got %d", got)
	}
}

// TestStateAutoHealFailurePath runs one orchestration or CLI step.
// Signature: TestStateAutoHealFailurePath(t *testing.T).
// Why: verifies corrupt-state auto-heal reports a useful error when filesystem permissions block quarantine.
func TestStateAutoHealFailurePath(t *testing.T) {
	root := t.TempDir()
	path := filepath.Join(root, "runs.json")
	if err := os.WriteFile(path, []byte("{invalid-json"), 0o600); err != nil {
		t.Fatalf("write corrupt runs file: %v", err)
	}
	restore := state.TestHookSetQuarantineCorruptFileOverride(func(path string, payload []byte, replacement []byte, mode os.FileMode) error {
		return errors.New("forced quarantine failure")
	})
	t.Cleanup(restore)

	_, err := state.New(path).Load()
	if err == nil {
		t.Fatalf("expected auto-heal failure when directory is not writable")
	}
	if !strings.Contains(err.Error(), "auto-heal failed") {
		t.Fatalf("expected auto-heal failure detail, got %v", err)
	}
}

// TestStateQuarantineHookBranches runs one orchestration or CLI step.
// Signature: TestStateQuarantineHookBranches(t *testing.T).
// Why: closes remaining corruption-heal branches so drill recovery file repair stays reliable.
func TestStateQuarantineHookBranches(t *testing.T) {
	root := t.TempDir()

	// Success path with backup+replacement writes.
	path := filepath.Join(root, "ok", "intent.json")
	if err := state.TestHookQuarantineCorruptFile(path, []byte("{bad"), []byte("{}\n"), 0o640); err != nil {
		t.Fatalf("expected successful quarantine write, got %v", err)
	}
	matches, err := filepath.Glob(path + ".corrupt-*")
	if err != nil {
		t.Fatalf("glob corrupt backups: %v", err)
	}
	if len(matches) == 0 {
		t.Fatalf("expected a .corrupt backup artifact")
	}

	// Parent is a file -> mkdir branch fails.
	parentFile := filepath.Join(root, "parent-as-file")
	if err := os.WriteFile(parentFile, []byte("x"), 0o600); err != nil {
		t.Fatalf("write parent file: %v", err)
	}
	err = state.TestHookQuarantineCorruptFile(filepath.Join(parentFile, "intent.json"), []byte("bad"), []byte("{}\n"), 0o640)
	if err == nil {
		t.Fatalf("expected mkdir failure when parent is a file")
	}

	// Long filename forces backup write failure branch regardless of root privileges.
	longName := strings.Repeat("a", 245)
	backupFailPath := filepath.Join(root, "long-name", longName)
	err = state.TestHookQuarantineCorruptFile(backupFailPath, []byte("bad"), []byte("{}\n"), 0o640)
	if err == nil || !strings.Contains(err.Error(), "write backup") {
		t.Fatalf("expected backup write failure for long-name backup path, got %v", err)
	}
}

// TestStateIntentParseAndWriteEdgeBranches runs one orchestration or CLI step.
// Signature: TestStateIntentParseAndWriteEdgeBranches(t *testing.T).
// Why: exercises parser and write edge paths that can otherwise hide intent-state drift.
func TestStateIntentParseAndWriteEdgeBranches(t *testing.T) {
	root := t.TempDir()

	// Parse branch where reason quote is malformed but token still parses.
	parsed, err := state.ParseIntentOutput(`intent=startup_in_progress reason="unterminated source=peer`)
	if err != nil {
		t.Fatalf("parse with malformed reason quote: %v", err)
	}
	if parsed.State != state.IntentStartupInProgress {
		t.Fatalf("unexpected parsed state: %+v", parsed)
	}

	// Parse branch with blank state token should normalize to zero intent.
	blank, err := state.ParseIntentOutput(`intent= source=peer`)
	if err != nil {
		t.Fatalf("parse blank intent token: %v", err)
	}
	if blank != (state.Intent{}) {
		t.Fatalf("expected zero intent for blank state token, got %+v", blank)
	}

	// WriteIntent branch with parent path not directory.
	parentFile := filepath.Join(root, "bad-parent")
	if err := os.WriteFile(parentFile, []byte("x"), 0o600); err != nil {
		t.Fatalf("write bad parent marker: %v", err)
	}
	if err := state.WriteIntent(filepath.Join(parentFile, "intent.json"), state.Intent{State: state.IntentNormal}); err == nil {
		t.Fatalf("expected WriteIntent error for invalid parent path")
	}
}

// TestStateStoreAppendAndAcquireBranches runs one orchestration or CLI step.
// Signature: TestStateStoreAppendAndAcquireBranches(t *testing.T).
// Why: covers append error and active-lock branches used by CLI locking semantics.
func TestStateStoreAppendAndAcquireBranches(t *testing.T) {
	root := t.TempDir()

	// Append should fail when parent path cannot be created as a directory.
	parentFile := filepath.Join(root, "runs-parent")
	if err := os.WriteFile(parentFile, []byte("x"), 0o600); err != nil {
		t.Fatalf("write append parent marker: %v", err)
	}
	st := state.New(filepath.Join(parentFile, "runs.json"))
	if err := st.Append(state.RunRecord{ID: "x", Action: "shutdown", StartedAt: time.Now(), EndedAt: time.Now(), DurationSeconds: 1, Success: true}); err == nil {
		t.Fatalf("expected append error when parent path is not a directory")
	}

	// AcquireLock active process branch: pid=1 should be treated as active on Linux.
	lockPath := filepath.Join(root, "active.lock")
	if err := os.WriteFile(lockPath, []byte("pid=1 started=1970-01-01T00:00:00Z\n"), 0o600); err != nil {
		t.Fatalf("write active lock: %v", err)
	}
	if _, err := state.AcquireLock(lockPath); err == nil || !strings.Contains(err.Error(), "active process") {
		t.Fatalf("expected active lock rejection, got %v", err)
	}
}