package supervisor

import (
	"context"
	"os"
	"os/exec"
	"path/filepath"
	"testing"
	"time"

	"github.com/dal/kaos/internal/config"
)

// setupE2E creates a temp directory with TASKS structure and a passing Go project.
func setupE2E(t *testing.T) (*Supervisor, string) {
	t.Helper()
	dir := t.TempDir()

	// Create TASKS structure
	tasksDir := filepath.Join(dir, "TASKS")
	for _, folder := range []string{"backlog", "ready", "active", "review", "done", "reports"} {
		os.MkdirAll(filepath.Join(tasksDir, folder), 0755)
	}

	// Create a passing Go project
	codeDir := filepath.Join(dir, "code")
	os.MkdirAll(codeDir, 0755)
	os.WriteFile(filepath.Join(codeDir, "go.mod"), []byte("module testproj\n\ngo 1.22\n"), 0644)
	os.WriteFile(filepath.Join(codeDir, "main.go"), []byte("package main\n\nfunc main() {}\n"), 0644)
	os.WriteFile(filepath.Join(codeDir, "main_test.go"), []byte("package main\n\nimport \"testing\"\n\nfunc TestMain(t *testing.T) {}\n"), 0644)

	cfg := &config.Config{
		Timeout:     30 * time.Second,
		ProjectPath: codeDir,
		TasksDir:    tasksDir,
	}

	sv := NewSupervisor(cfg)
	// Use mock command builder so we don't need real Claude CLI
	sv.CmdBuilder = func(ctx context.Context, task Task, projectPath string) *exec.Cmd {
		return exec.CommandContext(ctx, "echo", "mock agent output for "+task.ID)
	}

	return sv, dir
}

func writeTaskFile(t *testing.T, tasksDir, folder, filename, content string) {
	t.Helper()
	path := filepath.Join(tasksDir, folder, filename)
	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("write task file: %v", err)
	}
}

const e2eTask1 = `# T01: Bazni task

**Agent:** coder
**Model:** Sonnet
**Zavisi od:** —

---

## Opis

Bazni task koji nema zavisnosti.

---
`

const e2eTask2 = `# T02: Zavisni task

**Agent:** coder
**Model:** Sonnet
**Zavisi od:** T01

---

## Opis

Zavisi od T01.

---
`

func TestSupervisor_Run_EndToEnd(t *testing.T) {
	sv, _ := setupE2E(t)

	// Put task in ready
	writeTaskFile(t, sv.TasksDir, "ready", "T01.md", e2eTask1)

	err := sv.Run("T01")
	if err != nil {
		t.Fatalf("Run failed: %v", err)
	}

	// Verify task moved to review
	if _, err := os.Stat(filepath.Join(sv.TasksDir, "review", "T01.md")); err != nil {
		t.Error("expected T01.md in review/")
	}
	if _, err := os.Stat(filepath.Join(sv.TasksDir, "ready", "T01.md")); !os.IsNotExist(err) {
		t.Error("expected T01.md removed from ready/")
	}
	if _, err := os.Stat(filepath.Join(sv.TasksDir, "active", "T01.md")); !os.IsNotExist(err) {
		t.Error("expected T01.md removed from active/")
	}

	// Verify report written
	if _, err := os.Stat(filepath.Join(sv.ReportsDir, "T01-report.md")); err != nil {
		t.Error("expected T01-report.md in reports/")
	}
}

func TestSupervisor_RunNext_PicksCorrectTask(t *testing.T) {
	sv, _ := setupE2E(t)

	// T01 is done, T02 depends on T01 and is in ready
	writeTaskFile(t, sv.TasksDir, "done", "T01.md", e2eTask1)
	writeTaskFile(t, sv.TasksDir, "ready", "T02.md", e2eTask2)

	err := sv.RunNext()
	if err != nil {
		t.Fatalf("RunNext failed: %v", err)
	}

	// T02 should be in review now
	if _, err := os.Stat(filepath.Join(sv.TasksDir, "review", "T02.md")); err != nil {
		t.Error("expected T02.md in review/")
	}
}

func TestSupervisor_RunNext_BlockedTask(t *testing.T) {
	sv, _ := setupE2E(t)

	// T02 depends on T01, but T01 is NOT done (it's in backlog)
	writeTaskFile(t, sv.TasksDir, "backlog", "T01.md", e2eTask1)
	writeTaskFile(t, sv.TasksDir, "ready", "T02.md", e2eTask2)

	err := sv.RunNext()
	if err == nil {
		t.Fatal("expected error for blocked task")
	}
}

func TestSupervisor_RunNext_NoTasks(t *testing.T) {
	sv, _ := setupE2E(t)

	err := sv.RunNext()
	if err == nil {
		t.Fatal("expected error when no tasks available")
	}
}

func TestSupervisor_Run_TaskNotFound(t *testing.T) {
	sv, _ := setupE2E(t)

	err := sv.Run("T99")
	if err == nil {
		t.Fatal("expected error for nonexistent task")
	}
}

func TestSupervisor_Run_TaskNotReady(t *testing.T) {
	sv, _ := setupE2E(t)

	// Task in active, not ready
	writeTaskFile(t, sv.TasksDir, "active", "T01.md", e2eTask1)

	err := sv.Run("T01")
	if err == nil {
		t.Fatal("expected error for task not in ready/")
	}
}

func TestSupervisor_Run_FailedVerification(t *testing.T) {
	sv, _ := setupE2E(t)

	// Make the Go project fail by writing bad code
	os.WriteFile(filepath.Join(sv.CodeDir, "main.go"), []byte("package main\n\nfunc main() { BROKEN }\n"), 0644)

	writeTaskFile(t, sv.TasksDir, "ready", "T01.md", e2eTask1)

	err := sv.Run("T01")
	if err == nil {
		t.Fatal("expected error for failed verification")
	}

	// Task should still be moved to review even on failure
	if _, err := os.Stat(filepath.Join(sv.TasksDir, "review", "T01.md")); err != nil {
		t.Error("expected T01.md in review/ even after failure")
	}

	// Report should exist with failed status
	reportPath := filepath.Join(sv.ReportsDir, "T01-report.md")
	if _, err := os.Stat(reportPath); err != nil {
		t.Error("expected report to exist even for failed verification")
	}
}

func TestNewSupervisor(t *testing.T) {
	cfg := &config.Config{
		Timeout:     10 * time.Minute,
		ProjectPath: "/tmp/code",
		TasksDir:    "/tmp/tasks",
	}

	sv := NewSupervisor(cfg)

	if sv.Config != cfg {
		t.Error("expected config to be set")
	}
	if sv.TasksDir != "/tmp/tasks" {
		t.Errorf("expected TasksDir /tmp/tasks, got %s", sv.TasksDir)
	}
	if sv.CodeDir != "/tmp/code" {
		t.Errorf("expected CodeDir /tmp/code, got %s", sv.CodeDir)
	}
	if sv.ReportsDir != "/tmp/tasks/reports" {
		t.Errorf("expected ReportsDir /tmp/tasks/reports, got %s", sv.ReportsDir)
	}
}