package config

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestLoadSessionWithOptionsRejectsCompactPlaceholder(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: "{{session_id}}"
campaign: sample-campaign
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{SessionID: "2026-04-04"})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	assertConcreteSessionTemplateError(t, err, "session_id")
}

func TestLoadSessionWithOptionsRejectsSpacedPlaceholder(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: "{{ session_id }}"
previous_session_id: "{{ previous_session_id }}"
campaign: sample-campaign
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{
		SessionID:         "2026-04-04",
		PreviousSessionID: "2026-03-28",
	})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	assertConcreteSessionTemplateError(t, err, "session_id", "previous_session_id")
}

func TestLoadSessionWithOptionsMismatchFails(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: 2026-05-03
campaign: sample-campaign
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{SessionID: "2026-04-04"})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !strings.Contains(err.Error(), "session_id mismatch") {
		t.Fatalf("error = %q, want mismatch context", err.Error())
	}
	if strings.Contains(err.Error(), "rendered") {
		t.Fatalf("error = %q, should not mention rendered session", err.Error())
	}
}

func TestLoadSessionWithOptionsPreviousSessionMismatchFails(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: 2026-05-03
previous_session_id: 2026-04-26
campaign: sample-campaign
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{
		SessionID:         "2026-05-03",
		PreviousSessionID: "2026-04-25",
	})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !strings.Contains(err.Error(), "previous_session_id mismatch") {
		t.Fatalf("error = %q, want mismatch context", err.Error())
	}
	if strings.Contains(err.Error(), "rendered") {
		t.Fatalf("error = %q, should not mention rendered session", err.Error())
	}
}

func TestLoadSessionWithOptionsRequiresExpectedPreviousSession(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: 2026-05-03
campaign: sample-campaign
inputs:
  audio_dir: ./audio
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{PreviousSessionID: "2026-04-26"})
	if err == nil || !strings.Contains(err.Error(), "previous_session_id is required") {
		t.Fatalf("LoadSessionWithOptions() error = %v, want missing previous-session expectation error", err)
	}
}

func TestLoadSessionWithOptionsUnknownFieldStillRejected(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: 2026-04-04
campaign: sample-campaign
unknown_field: true
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	_, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{SessionID: "2026-04-04"})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !strings.Contains(err.Error(), "strict decode failed") {
		t.Fatalf("error = %q, want strict-decode context", err.Error())
	}
}

func TestLoadSessionWithOptionsConcreteSessionStillLoads(t *testing.T) {
	dir := t.TempDir()
	sessionPath := filepath.Join(dir, "session.yml")
	sessionYAML := `session_id: 2026-05-03
campaign: sample-campaign
inputs:
  audio_dir: ./audio
  speakers_file: ./speakers.yml
  autocorrect_file: ./autocorrect.yml
  glossary_file: ./glossary.yml
  players_file: ./players.yml
  party_file: ./party.yml
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	cfg, err := LoadSessionWithOptions(sessionPath, SessionLoadOptions{})
	if err != nil {
		t.Fatalf("LoadSessionWithOptions() error = %v", err)
	}
	if cfg.SessionID != "2026-05-03" {
		t.Fatalf("SessionID = %q, want 2026-05-03", cfg.SessionID)
	}
}

func TestLoadSessionBytesWithOptionsRejectsPlaceholder(t *testing.T) {
	sessionYAML := []byte(`session_id: "{{ session_id }}"
campaign: sample-campaign
inputs:
  audio_s3:
    prefix: audio/
`)

	_, err := LoadSessionBytesWithOptions("s3://bucket/session.yml", sessionYAML, SessionLoadOptions{SessionID: "2026-05-03"})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	assertConcreteSessionTemplateError(t, err, "session_id")
}

func TestLoadSessionBytesWithOptionsStrictDecode(t *testing.T) {
	cfg, err := LoadSessionBytesWithOptions("s3://bucket/session.yml", []byte("session_id: 2026-05-03\n"), SessionLoadOptions{})
	if err != nil {
		t.Fatalf("LoadSessionBytesWithOptions() error = %v", err)
	}
	if cfg.SessionID != "2026-05-03" {
		t.Fatalf("SessionID = %q, want 2026-05-03", cfg.SessionID)
	}

	_, err = LoadSessionBytesWithOptions("s3://bucket/session.yml", []byte("session_id: 2026-05-03\nunknown: true\n"), SessionLoadOptions{})
	if err == nil {
		t.Fatal("expected strict decode error, got nil")
	}
	if !strings.Contains(err.Error(), "strict decode failed") {
		t.Fatalf("error = %q, want strict decode context", err.Error())
	}
}

func TestLoadSessionBytesWithOptionsMismatchFails(t *testing.T) {
	_, err := LoadSessionBytesWithOptions("s3://bucket/session.yml", []byte("session_id: 2026-05-03\n"), SessionLoadOptions{SessionID: "2026-04-04"})
	if err == nil {
		t.Fatal("expected mismatch error, got nil")
	}
	if !strings.Contains(err.Error(), "session_id mismatch") {
		t.Fatalf("error = %q, want mismatch context", err.Error())
	}
}

func TestLoadSessionBytesWithOptionsRequiresExpectedPreviousSession(t *testing.T) {
	_, err := LoadSessionBytesWithOptions(
		"s3://bucket/session.yml",
		[]byte("session_id: 2026-05-03\n"),
		SessionLoadOptions{PreviousSessionID: "2026-04-26"},
	)
	if err == nil || !strings.Contains(err.Error(), "previous_session_id is required") {
		t.Fatalf("LoadSessionBytesWithOptions() error = %v, want missing previous-session expectation error", err)
	}
}

func assertConcreteSessionTemplateError(t *testing.T, err error, vars ...string) {
	t.Helper()
	if !strings.Contains(err.Error(), "session.yml must be concrete") {
		t.Fatalf("error = %q, want concrete session guidance", err.Error())
	}
	if !strings.Contains(err.Error(), "run narratio session init") {
		t.Fatalf("error = %q, want session init guidance", err.Error())
	}
	for _, name := range vars {
		if !strings.Contains(err.Error(), name) {
			t.Fatalf("error = %q, want variable %q", err.Error(), name)
		}
	}
}