package validator

import (
	"bufio"
	"encoding/json"
	"os"
	"path/filepath"
	"sync"
	"testing"
)

func TestSessionLogger_AppendsSchemaTaggedRows(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "sessions.jsonl")
	logger := NewSessionLogger(path)
	if logger == nil {
		t.Fatal("expected non-nil logger for a non-empty path")
	}

	rec := SessionRecord{
		SessionID:    "trace-1",
		Kind:         "fill",
		Model:        "qwen3.5:latest",
		Provider:     "ollama",
		Prompt:       "produce a fill artifact",
		Iterations:   1,
		FinalVerdict: "accepted",
	}
	logger.Append(rec)

	rows := readJSONL(t, path)
	if len(rows) != 1 {
		t.Fatalf("expected 1 row, got %d", len(rows))
	}
	if rows[0]["schema"] != SessionRecordSchema {
		t.Errorf("schema autopopulation: %v", rows[0]["schema"])
	}
	if rows[0]["session_id"] != "trace-1" {
		t.Errorf("session_id round-trip: %v", rows[0]["session_id"])
	}
	if rows[0]["timestamp"] == "" || rows[0]["timestamp"] == nil {
		t.Errorf("timestamp autopopulation: %v", rows[0]["timestamp"])
	}
	if rows[0]["daemon"] != "validatord" {
		t.Errorf("daemon autopopulation: %v", rows[0]["daemon"])
	}
}

func TestSessionLogger_NilIsNoOp(t *testing.T) {
	var logger *SessionLogger // nil
	logger.Append(SessionRecord{SessionID: "trace-1"})
	// No panic, no error — the test passing IS the assertion.
}

func TestSessionLogger_EmptyPathReturnsNil(t *testing.T) {
	if NewSessionLogger("") != nil {
		t.Error("empty path should disable logging (nil logger)")
	}
}

// TestSessionLogger_ConcurrentAppends locks the per-row atomicity: N
// goroutines each appending must produce N well-formed JSONL rows
// with no torn writes. Mutex lives at the logger level, not OS-level,
// so this also documents that concurrent logger instances would NOT
// be safe (one logger per daemon — that's fine).
func TestSessionLogger_ConcurrentAppends(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "sessions.jsonl")
	logger := NewSessionLogger(path)

	const N = 64
	var wg sync.WaitGroup
	for i := 0; i < N; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			logger.Append(SessionRecord{
				SessionID:    "trace-" + string(rune('a'+i%26)),
				Kind:         "fill",
				FinalVerdict: "accepted",
				Iterations:   i,
			})
		}(i)
	}
	wg.Wait()

	rows := readJSONL(t, path)
	if len(rows) != N {
		t.Fatalf("expected %d rows after concurrent appends, got %d", N, len(rows))
	}
	// Every row must be parseable JSON — a torn write would throw
	// a decode error, which readJSONL t.Fatal's on.
}

func TestBuildSessionRecord_SuccessPathCapturesArtifact(t *testing.T) {
	req := IterateRequest{
		TraceID:       "trace-x",
		Kind:          "fill",
		Prompt:        "produce fill",
		Provider:      "ollama",
		Model:         "qwen3.5:latest",
		MaxIterations: 3,
	}
	resp := &IterateResponse{
		Artifact: map[string]any{"fills": []any{
			map[string]any{"candidate_id": "W-1"},
		}},
		Validation: Report{},
		Iterations: 1,
		History: []IterateAttempt{{
			Iteration: 0,
			Raw:       `{"fills":[{"candidate_id":"W-1"}]}`,
			Status:    AttemptStatus{Kind: "accepted"},
			SpanID:    "span-0",
		}},
		TraceID: "trace-x",
	}
	roster := func(_ map[string]any) *bool {
		t := true
		return &t
	}
	rec := BuildSessionRecord(req, resp, nil, nil, roster, 1234)
	if rec.FinalVerdict != "accepted" || rec.Iterations != 1 {
		t.Errorf("verdict/iterations: %+v", rec)
	}
	if rec.GroundedInRoster == nil || !*rec.GroundedInRoster {
		t.Errorf("grounded_in_roster: expected true, got %v", rec.GroundedInRoster)
	}
	if rec.Artifact == nil {
		t.Errorf("artifact missing on success path")
	}
	if len(rec.Attempts) != 1 || rec.Attempts[0].SpanID != "span-0" {
		t.Errorf("attempts shape: %+v", rec.Attempts)
	}
	if rec.SessionID != "trace-x" {
		t.Errorf("session_id: %s", rec.SessionID)
	}
	if rec.DurationMs != 1234 {
		t.Errorf("duration: %d", rec.DurationMs)
	}
}

func TestBuildSessionRecord_FailurePathOmitsArtifact(t *testing.T) {
	req := IterateRequest{
		TraceID:       "trace-y",
		Kind:          "fill",
		Provider:      "ollama",
		Model:         "qwen",
		MaxIterations: 3,
	}
	fail := &IterateFailure{
		Error:      "max iterations reached (3)",
		Iterations: 3,
		History: []IterateAttempt{
			{Iteration: 0, Status: AttemptStatus{Kind: "no_json"}},
			{Iteration: 1, Status: AttemptStatus{Kind: "validation_failed", Error: "phantom W-X"}},
			{Iteration: 2, Status: AttemptStatus{Kind: "validation_failed", Error: "phantom W-Y"}},
		},
		TraceID: "trace-y",
	}
	rec := BuildSessionRecord(req, nil, fail, nil, nil, 8765)
	if rec.FinalVerdict != "max_iter_exhausted" {
		t.Errorf("final_verdict: %s", rec.FinalVerdict)
	}
	if rec.Artifact != nil {
		t.Errorf("artifact must be omitted on failure path: %v", rec.Artifact)
	}
	if rec.GroundedInRoster != nil {
		t.Errorf("grounded_in_roster should be nil on failure: %v", *rec.GroundedInRoster)
	}
	if len(rec.Attempts) != 3 || rec.Attempts[2].VerdictKind != "validation_failed" {
		t.Errorf("attempts: %+v", rec.Attempts)
	}
}

func TestBuildSessionRecord_InfraErrorEmitsRow(t *testing.T) {
	// An infrastructure failure (e.g. chat hop crashed) must STILL
	// produce a session row — otherwise debugging gets harder
	// (no log → operator can't see it failed at all).
	req := IterateRequest{TraceID: "trace-z", Kind: "fill"}
	rec := BuildSessionRecord(req, nil, nil, errExample{"chat refused"}, nil, 50)
	if rec.FinalVerdict != "infra_error" {
		t.Errorf("verdict: %s", rec.FinalVerdict)
	}
	if len(rec.Attempts) != 1 || rec.Attempts[0].VerdictKind != "infra_error" {
		t.Errorf("attempts: %+v", rec.Attempts)
	}
	if rec.Attempts[0].Error == "" {
		t.Errorf("error must be carried")
	}
}

// ─── Helpers ───────────────────────────────────────────────────

type errExample struct{ msg string }

func (e errExample) Error() string { return e.msg }

func readJSONL(t *testing.T, path string) []map[string]any {
	t.Helper()
	f, err := os.Open(path)
	if err != nil {
		t.Fatalf("open: %v", err)
	}
	defer f.Close()
	var out []map[string]any
	sc := bufio.NewScanner(f)
	sc.Buffer(make([]byte, 0, 1<<16), 1<<24)
	for sc.Scan() {
		line := sc.Bytes()
		if len(line) == 0 {
			continue
		}
		var row map[string]any
		if err := json.Unmarshal(line, &row); err != nil {
			t.Fatalf("parse line %q: %v", line, err)
		}
		out = append(out, row)
	}
	if err := sc.Err(); err != nil {
		t.Fatalf("scan: %v", err)
	}
	return out
}