package supervisor

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

// setupTempGoProject creates a minimal Go project in a temp directory.
func setupTempGoProject(t *testing.T, mainContent, testContent string) string {
	t.Helper()
	dir := t.TempDir()

	// go.mod
	goMod := "module tempproject\n\ngo 1.22\n"
	if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte(goMod), 0644); err != nil {
		t.Fatalf("write go.mod: %v", err)
	}

	// main.go
	if err := os.WriteFile(filepath.Join(dir, "main.go"), []byte(mainContent), 0644); err != nil {
		t.Fatalf("write main.go: %v", err)
	}

	// test file (optional)
	if testContent != "" {
		if err := os.WriteFile(filepath.Join(dir, "main_test.go"), []byte(testContent), 0644); err != nil {
			t.Fatalf("write main_test.go: %v", err)
		}
	}

	return dir
}

func TestVerify_PassingProject(t *testing.T) {
	mainGo := `package main

import "fmt"

func main() {
	fmt.Println("hello")
}

func Add(a, b int) int {
	return a + b
}
`
	testGo := `package main

import "testing"

func TestAdd(t *testing.T) {
	if Add(1, 2) != 3 {
		t.Fatal("expected 3")
	}
}

func TestAddZero(t *testing.T) {
	if Add(0, 0) != 0 {
		t.Fatal("expected 0")
	}
}
`
	dir := setupTempGoProject(t, mainGo, testGo)

	result := Verify(dir)

	if !result.AllPassed {
		t.Errorf("expected AllPassed=true\nBuild: %s %s\nVet: %s %s\nTest: %s %s",
			result.Build.Status, result.Build.Output,
			result.Vet.Status, result.Vet.Output,
			result.Test.Status, result.Test.Output)
	}

	if result.Build.Status != "pass" {
		t.Errorf("expected build pass, got %s", result.Build.Status)
	}
	if result.Vet.Status != "pass" {
		t.Errorf("expected vet pass, got %s", result.Vet.Status)
	}
	if result.Test.Status != "pass" {
		t.Errorf("expected test pass, got %s", result.Test.Status)
	}
	if result.Test.TestCount != 2 {
		t.Errorf("expected 2 tests, got %d", result.Test.TestCount)
	}
}

func TestVerify_BuildFail(t *testing.T) {
	badGo := `package main

func main() {
	this is not valid go code
}
`
	dir := setupTempGoProject(t, badGo, "")

	result := Verify(dir)

	if result.AllPassed {
		t.Error("expected AllPassed=false")
	}
	if result.Build.Status != "fail" {
		t.Errorf("expected build fail, got %s", result.Build.Status)
	}
	// Vet and test should be skipped
	if result.Vet.Status != "fail" {
		t.Errorf("expected vet fail (skipped), got %s", result.Vet.Status)
	}
	if result.Test.Status != "fail" {
		t.Errorf("expected test fail (skipped), got %s", result.Test.Status)
	}
}

func TestVerify_TestFail(t *testing.T) {
	mainGo := `package main

func main() {}

func Broken() int {
	return 42
}
`
	testGo := `package main

import "testing"

func TestBroken(t *testing.T) {
	if Broken() != 99 {
		t.Fatal("expected 99")
	}
}
`
	dir := setupTempGoProject(t, mainGo, testGo)

	result := Verify(dir)

	if result.AllPassed {
		t.Error("expected AllPassed=false")
	}
	if result.Build.Status != "pass" {
		t.Errorf("expected build pass, got %s", result.Build.Status)
	}
	if result.Test.Status != "fail" {
		t.Errorf("expected test fail, got %s", result.Test.Status)
	}
}

func TestVerify_Duration(t *testing.T) {
	mainGo := `package main

func main() {}
`
	dir := setupTempGoProject(t, mainGo, "")

	result := Verify(dir)

	if result.Build.Duration <= 0 {
		t.Error("expected build duration > 0")
	}
	if result.Vet.Duration <= 0 {
		t.Error("expected vet duration > 0")
	}
	if result.Test.Duration <= 0 {
		t.Error("expected test duration > 0")
	}
}

func TestVerify_OutputPopulated(t *testing.T) {
	mainGo := `package main

func main() {}
`
	testGo := `package main

import "testing"

func TestNothing(t *testing.T) {}
`
	dir := setupTempGoProject(t, mainGo, testGo)

	result := Verify(dir)

	// Test output should contain test results
	if result.Test.Output == "" {
		t.Error("expected non-empty test output")
	}
}

func TestParseTestCount_PassingTests(t *testing.T) {
	output := `=== RUN   TestAdd
--- PASS: TestAdd (0.00s)
=== RUN   TestSub
--- PASS: TestSub (0.00s)
PASS
ok  	github.com/dal/kaos	0.003s
`
	count := parseTestCount(output)
	if count != 2 {
		t.Errorf("expected 2, got %d", count)
	}
}

func TestParseTestCount_MixedResults(t *testing.T) {
	output := `=== RUN   TestGood
--- PASS: TestGood (0.00s)
=== RUN   TestBad
--- FAIL: TestBad (0.00s)
FAIL
`
	count := parseTestCount(output)
	if count != 2 {
		t.Errorf("expected 2, got %d", count)
	}
}

func TestParseTestCount_NoTests(t *testing.T) {
	output := "FAIL\n"
	count := parseTestCount(output)
	if count != 0 {
		t.Errorf("expected 0, got %d", count)
	}
}

func TestParseTestCount_Empty(t *testing.T) {
	count := parseTestCount("")
	if count != 0 {
		t.Errorf("expected 0, got %d", count)
	}
}

func TestFormatResult(t *testing.T) {
	result := VerifyResult{
		Build:     CheckResult{Name: "build", Status: "pass"},
		Vet:       CheckResult{Name: "vet", Status: "pass"},
		Test:      CheckResult{Name: "test", Status: "pass", TestCount: 5},
		AllPassed: true,
	}

	out := FormatResult(result)
	if out == "" {
		t.Error("expected non-empty format output")
	}
	if !contains(out, "All checks passed") {
		t.Errorf("expected 'All checks passed' in output, got: %s", out)
	}
	if !contains(out, "5 tests") {
		t.Errorf("expected '5 tests' in output, got: %s", out)
	}
}

func contains(s, substr string) bool {
	return len(s) >= len(substr) && searchString(s, substr)
}

func searchString(s, substr string) bool {
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}