package ezconf

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

func TestPrintEnvVars(t *testing.T) {
	loader := New()
	loader.envVars = []EnvVar{
		{
			Name:         "LOG_LEVEL",
			Description:  "Log level",
			Required:     false,
			Default:      "info",
			CurrentValue: "debug",
		},
		{
			Name:         "DATABASE_URL",
			Description:  "Database connection",
			Required:     true,
			Default:      "",
			CurrentValue: "postgres://localhost/db",
		},
	}

	// Test without values
	t.Run("without values", func(t *testing.T) {
		buf := &bytes.Buffer{}
		err := loader.PrintEnvVars(buf, false)
		if err != nil {
			t.Fatalf("PrintEnvVars failed: %v", err)
		}

		output := buf.String()
		if !strings.Contains(output, "LOG_LEVEL") {
			t.Error("output should contain LOG_LEVEL")
		}
		if !strings.Contains(output, "Log level") {
			t.Error("output should contain description")
		}
		if !strings.Contains(output, "(default: info)") {
			t.Error("output should contain default value")
		}
		if strings.Contains(output, "debug") {
			t.Error("output should not contain current value when showValues is false")
		}
	})

	// Test with values
	t.Run("with values", func(t *testing.T) {
		buf := &bytes.Buffer{}
		err := loader.PrintEnvVars(buf, true)
		if err != nil {
			t.Fatalf("PrintEnvVars failed: %v", err)
		}

		output := buf.String()
		if !strings.Contains(output, "LOG_LEVEL=debug") {
			t.Error("output should contain LOG_LEVEL=debug")
		}
		if !strings.Contains(output, "DATABASE_URL=postgres://localhost/db") {
			t.Error("output should contain DATABASE_URL value")
		}
		if !strings.Contains(output, "(required)") {
			t.Error("output should indicate required variables")
		}
	})
}

func TestGenerateEnvFile(t *testing.T) {
	loader := New()
	loader.envVars = []EnvVar{
		{
			Name:         "LOG_LEVEL",
			Description:  "Log level",
			Required:     false,
			Default:      "info",
			CurrentValue: "debug",
		},
		{
			Name:         "DATABASE_URL",
			Description:  "Database connection",
			Required:     true,
			Default:      "postgres://localhost/db",
			CurrentValue: "",
		},
	}

	tempDir := t.TempDir()

	t.Run("generate with defaults", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "test1.env")

		err := loader.GenerateEnvFile(envFile, false)
		if err != nil {
			t.Fatalf("GenerateEnvFile failed: %v", err)
		}

		content, err := os.ReadFile(envFile)
		if err != nil {
			t.Fatalf("failed to read generated file: %v", err)
		}

		output := string(content)
		if !strings.Contains(output, "LOG_LEVEL=info") {
			t.Error("expected default value for LOG_LEVEL")
		}
		if !strings.Contains(output, "# Log level") {
			t.Error("expected description comment")
		}
		if !strings.Contains(output, "# Database connection") {
			t.Error("expected DATABASE_URL description")
		}
	})

	t.Run("generate with current values", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "test2.env")

		err := loader.GenerateEnvFile(envFile, true)
		if err != nil {
			t.Fatalf("GenerateEnvFile failed: %v", err)
		}

		content, err := os.ReadFile(envFile)
		if err != nil {
			t.Fatalf("failed to read generated file: %v", err)
		}

		output := string(content)
		if !strings.Contains(output, "LOG_LEVEL=debug") {
			t.Error("expected current value for LOG_LEVEL")
		}
		// DATABASE_URL has no current value, should use default
		if !strings.Contains(output, "DATABASE_URL=postgres://localhost/db") {
			t.Error("expected default value for DATABASE_URL when current is empty")
		}
	})

	t.Run("preserve untracked variables", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "test3.env")

		// Create existing file with untracked variable
		existing := `# Existing file
LOG_LEVEL=warn
CUSTOM_VAR=custom_value
ANOTHER_VAR=another_value
`
		if err := os.WriteFile(envFile, []byte(existing), 0644); err != nil {
			t.Fatalf("failed to create existing file: %v", err)
		}

		// Generate new file - should preserve untracked variables
		err := loader.GenerateEnvFile(envFile, false)
		if err != nil {
			t.Fatalf("GenerateEnvFile failed: %v", err)
		}

		content, err := os.ReadFile(envFile)
		if err != nil {
			t.Fatalf("failed to read generated file: %v", err)
		}

		output := string(content)
		// Should have tracked variables with new format
		if !strings.Contains(output, "LOG_LEVEL") {
			t.Error("expected LOG_LEVEL to be present")
		}
		if !strings.Contains(output, "DATABASE_URL") {
			t.Error("expected DATABASE_URL to be present")
		}
		// Should preserve untracked variables
		if !strings.Contains(output, "CUSTOM_VAR=custom_value") {
			t.Error("expected to preserve CUSTOM_VAR")
		}
		if !strings.Contains(output, "ANOTHER_VAR=another_value") {
			t.Error("expected to preserve ANOTHER_VAR")
		}
		// Should have untracked section header
		if !strings.Contains(output, "Untracked Variables") {
			t.Error("expected untracked variables section header")
		}
	})
}

func TestUpdateEnvFile(t *testing.T) {
	loader := New()
	loader.envVars = []EnvVar{
		{
			Name:        "LOG_LEVEL",
			Description: "Log level",
			Default:     "info",
		},
		{
			Name:        "NEW_VAR",
			Description: "New variable",
			Default:     "new_default",
		},
	}

	tempDir := t.TempDir()

	t.Run("update existing file", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "existing.env")

		// Create existing file
		existing := `# Existing file
LOG_LEVEL=debug
OLD_VAR=old_value
`
		if err := os.WriteFile(envFile, []byte(existing), 0644); err != nil {
			t.Fatalf("failed to create existing file: %v", err)
		}

		err := loader.UpdateEnvFile(envFile, false)
		if err != nil {
			t.Fatalf("UpdateEnvFile failed: %v", err)
		}

		content, err := os.ReadFile(envFile)
		if err != nil {
			t.Fatalf("failed to read updated file: %v", err)
		}

		output := string(content)
		// Should preserve existing value
		if !strings.Contains(output, "LOG_LEVEL=debug") {
			t.Error("expected to preserve existing LOG_LEVEL value")
		}
		// Should keep old variable
		if !strings.Contains(output, "OLD_VAR=old_value") {
			t.Error("expected to preserve OLD_VAR")
		}
		// Should add new variable
		if !strings.Contains(output, "NEW_VAR=new_default") {
			t.Error("expected to add NEW_VAR")
		}
	})

	t.Run("create if not exist", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "new.env")

		err := loader.UpdateEnvFile(envFile, true)
		if err != nil {
			t.Fatalf("UpdateEnvFile failed: %v", err)
		}

		if _, err := os.Stat(envFile); os.IsNotExist(err) {
			t.Error("expected file to be created")
		}
	})

	t.Run("error if not exist and no create", func(t *testing.T) {
		envFile := filepath.Join(tempDir, "nonexistent.env")

		err := loader.UpdateEnvFile(envFile, false)
		if err == nil {
			t.Error("expected error for nonexistent file")
		}
	})
}

func TestParseEnvFile(t *testing.T) {
	tempDir := t.TempDir()
	envFile := filepath.Join(tempDir, "test.env")

	content := `# Comment line
VAR1=value1
VAR2=value2

# Another comment
VAR3=value3
EMPTY_VAR=
`

	if err := os.WriteFile(envFile, []byte(content), 0644); err != nil {
		t.Fatalf("failed to create test file: %v", err)
	}

	lines, err := parseEnvFile(envFile)
	if err != nil {
		t.Fatalf("parseEnvFile failed: %v", err)
	}

	varCount := 0
	for _, line := range lines {
		if line.IsVar {
			varCount++
		}
	}

	if varCount != 4 {
		t.Errorf("expected 4 variables, got %d", varCount)
	}

	// Check specific variables
	found := false
	for _, line := range lines {
		if line.IsVar && line.Key == "VAR1" && line.Value == "value1" {
			found = true
			break
		}
	}
	if !found {
		t.Error("expected to find VAR1=value1")
	}
}

func TestParseEnvFile_InvalidFile(t *testing.T) {
	_, err := parseEnvFile("/nonexistent/file.env")
	if err == nil {
		t.Error("expected error for nonexistent file")
	}
}

func TestPrintEnvVars_NoEnvVars(t *testing.T) {
	loader := New()

	buf := &bytes.Buffer{}
	err := loader.PrintEnvVars(buf, false)
	if err == nil {
		t.Error("expected error when no env vars are loaded")
	}
	if !strings.Contains(err.Error(), "did you call Load()") {
		t.Errorf("expected helpful error message, got: %v", err)
	}
}

func TestPrintEnvVarsStdout(t *testing.T) {
	loader := New()
	loader.envVars = []EnvVar{
		{
			Name:        "TEST_VAR",
			Description: "Test variable",
			Default:     "test",
		},
	}

	// This test just ensures it doesn't panic
	// We can't easily capture stdout in a unit test without redirecting it
	err := loader.PrintEnvVarsStdout(false)
	if err != nil {
		t.Errorf("PrintEnvVarsStdout(false) failed: %v", err)
	}

	err = loader.PrintEnvVarsStdout(true)
	if err != nil {
		t.Errorf("PrintEnvVarsStdout(true) failed: %v", err)
	}
}

func TestPrintEnvVarsStdout_NoEnvVars(t *testing.T) {
	loader := New()

	err := loader.PrintEnvVarsStdout(false)
	if err == nil {
		t.Error("expected error when no env vars are loaded")
	}
}