package app

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

func TestPlanUsesDiscoveredSessionTemplateWithSessionIDs(t *testing.T) {
	workspaceRoot := t.TempDir()
	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)

	sessionTemplate := `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
`
	if err := os.WriteFile(sessionPath, []byte(sessionTemplate), 0o644); err != nil {
		t.Fatalf("write session template: %v", err)
	}

	cwd := filepath.Dir(sessionPath)
	originalWD, err := os.Getwd()
	if err != nil {
		t.Fatalf("Getwd(): %v", err)
	}
	if err := os.Chdir(cwd); err != nil {
		t.Fatalf("Chdir(%q): %v", cwd, err)
	}
	t.Cleanup(func() { _ = os.Chdir(originalWD) })

	var out bytes.Buffer
	if err := Plan(context.Background(), []string{
		"--config", pipelinePath,
		"--session-id", "2026-04-04",
		"--previous-session-id", "2026-03-28",
	}, &out); err != nil {
		t.Fatalf("Plan() error = %v", err)
	}
	if !strings.Contains(out.String(), "narratio plan: workdir prepared") {
		t.Fatalf("output = %q, want plan output", out.String())
	}
}

func TestPlanFailsWhenSessionIDMismatchesConcreteSession(t *testing.T) {
	workspaceRoot := t.TempDir()
	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)

	var out bytes.Buffer
	err := Plan(context.Background(), []string{"--config", pipelinePath, "--session", sessionPath, "--session-id", "2026-04-04"}, &out)
	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())
	}
}

func TestPlanFailsWhenPreviousSessionIDMismatchesConcreteSession(t *testing.T) {
	workspaceRoot := t.TempDir()
	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)

	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
`
	if err := os.WriteFile(sessionPath, []byte(sessionYAML), 0o644); err != nil {
		t.Fatalf("write session.yml: %v", err)
	}

	var out bytes.Buffer
	err := Plan(context.Background(), []string{
		"--config", pipelinePath,
		"--session", sessionPath,
		"--session-id", "2026-05-03",
		"--previous-session-id", "2026-04-25",
	}, &out)
	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())
	}
}

func TestRunStageAcceptsSessionIDFlagAndParsesStageName(t *testing.T) {
	workspaceRoot := t.TempDir()
	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)

	var out bytes.Buffer
	err := RunStage(context.Background(), []string{"--config", pipelinePath, "--session", sessionPath, "--session-id", "2026-05-03", "prepare"}, &out)
	if err != nil {
		t.Fatalf("RunStage() error = %v", err)
	}
	if !strings.Contains(out.String(), "stage=prepare") {
		t.Fatalf("output = %q, want stage output", out.String())
	}
}

func TestResolveSessionConfigPathErrorIncludesSearchedPaths(t *testing.T) {
	_, err := resolveSessionConfigPathWithCandidates("", []string{"./session.yml", "/usr/local/etc/narratio/session.yml", "/etc/narratio/session.yml"})
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !strings.Contains(err.Error(), "searched") {
		t.Fatalf("error = %q, want searched paths", err.Error())
	}
	if !strings.Contains(err.Error(), "pass --session") {
		t.Fatalf("error = %q, want explicit-session guidance", err.Error())
	}
}