package config

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

func writeConf(t *testing.T, content string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "update.conf")
	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
		t.Fatalf("seed: %v", err)
	}
	return path
}

func TestLoadMissingReturnsEmptyConfig(t *testing.T) {
	c, err := Load(filepath.Join(t.TempDir(), "does-not-exist.conf"))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if c == nil {
		t.Fatal("Load returned nil config")
	}
	if c.Server != "" || c.Channel != "" || c.MaintenanceWindow != "" || c.PubKey != "" {
		t.Errorf("expected empty config, got %+v", c)
	}
}

func TestLoadAllFields(t *testing.T) {
	path := writeConf(t, `# comment line
server = https://updates.example.com
channel = stable
maintenance_window = 03:00-05:00
pubkey = /etc/kubesolo/pub.hex
`)
	c, err := Load(path)
	if err != nil {
		t.Fatalf("load: %v", err)
	}
	if c.Server != "https://updates.example.com" {
		t.Errorf("server: got %q", c.Server)
	}
	if c.Channel != "stable" {
		t.Errorf("channel: got %q", c.Channel)
	}
	if c.MaintenanceWindow != "03:00-05:00" {
		t.Errorf("maintenance_window: got %q", c.MaintenanceWindow)
	}
	if c.PubKey != "/etc/kubesolo/pub.hex" {
		t.Errorf("pubkey: got %q", c.PubKey)
	}
}

func TestLoadIgnoresUnknownKeys(t *testing.T) {
	// Unknown keys must not be an error — supports forward-compat config
	// fields added by newer agent versions.
	path := writeConf(t, `server = https://x
future_field = whatever
channel = beta
`)
	c, err := Load(path)
	if err != nil {
		t.Fatalf("load: %v", err)
	}
	if c.Server != "https://x" {
		t.Errorf("server: got %q", c.Server)
	}
	if c.Channel != "beta" {
		t.Errorf("channel: got %q", c.Channel)
	}
}

func TestLoadStripsWhitespace(t *testing.T) {
	path := writeConf(t, "   server   =   https://example   \n  channel=stable\n")
	c, err := Load(path)
	if err != nil {
		t.Fatalf("load: %v", err)
	}
	if c.Server != "https://example" {
		t.Errorf("server: got %q (whitespace not stripped?)", c.Server)
	}
	if c.Channel != "stable" {
		t.Errorf("channel: got %q", c.Channel)
	}
}

func TestLoadIgnoresBlankAndCommentLines(t *testing.T) {
	path := writeConf(t, `
# this is a comment

server = https://example
   # indented comment
channel = stable

`)
	c, err := Load(path)
	if err != nil {
		t.Fatalf("load: %v", err)
	}
	if c.Server != "https://example" {
		t.Errorf("server: got %q", c.Server)
	}
}

func TestLoadRejectsMissingEquals(t *testing.T) {
	// "noEqualsHere" with no '=' is a syntax error worth surfacing — likely
	// indicates a corrupted config file.
	path := writeConf(t, `server = https://example
noEqualsHere
`)
	_, err := Load(path)
	if err == nil {
		t.Error("expected error on malformed line, got nil")
	}
}