package config

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

func TestFieldSourcesLayerAttribution(t *testing.T) {
	dir := t.TempDir()
	envf := filepath.Join(dir, ".env")
	if err := os.WriteFile(envf, []byte("HTTP_HOST=0.0.0.0\nKB_DB_PASSWORD=from-file\nAGENT_BACKEND=stub\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	t.Setenv("KB_DB_PASSWORD", "from-process") // 进程 env 覆盖 env-file

	cfg, src, err := LoadWithSources(envf, nil)
	if err != nil {
		t.Fatalf("load: %v", err)
	}
	if cfg.HTTPHost != "0.0.0.0" || cfg.KbDbPassword != "from-process" || cfg.AgentBackend != "stub" {
		t.Fatalf("values not applied: host=%s", cfg.HTTPHost)
	}
	if src["http_host"].Layer != "env-file:"+filepath.ToSlash(envf) {
		t.Fatalf("http_host layer=%s", src["http_host"].Layer)
	}
	if src["kb_db_password"].Layer != "process-env" {
		t.Fatalf("kb_db_password layer=%s", src["kb_db_password"].Layer)
	}
	if src["agent_backend"].Layer != "env-file:"+filepath.ToSlash(envf) {
		t.Fatalf("agent_backend layer=%s", src["agent_backend"].Layer)
	}
	// 未设置字段仍是 default 层
	if src["admin_username"].Layer != "default" || src["admin_username"].Set {
		t.Fatalf("admin_username layer=%s set=%v", src["admin_username"].Layer, src["admin_username"].Set)
	}
}

func TestApplyCLIOverridesAttribution(t *testing.T) {
	cfg, src, err := LoadWithSources("", nil)
	if err != nil {
		t.Fatal(err)
	}
	src2, err := ApplyCLIOverrides(cfg, src, func(c *Config) {
		c.HTTPPort = 9999
		c.AgentBackend = "stub"
	})
	if err != nil {
		t.Fatal(err)
	}
	if src2["http_port"].Layer != "cli" || !src2["http_port"].Set {
		t.Fatalf("http_port layer=%s set=%v", src2["http_port"].Layer, src2["http_port"].Set)
	}
	if src2["agent_backend"].Layer != "cli" {
		t.Fatalf("agent_backend layer=%s", src2["agent_backend"].Layer)
	}
	// 未覆盖字段来源不变
	if src2["http_host"].Layer != src["http_host"].Layer {
		t.Fatalf("http_host layer changed unexpectedly")
	}
}

// Load 行为回归：老入口签名与结果不变。
func TestLoadStillWorks(t *testing.T) {
	cfg, err := Load("")
	if err != nil {
		t.Fatal(err)
	}
	if cfg.HTTPPort == 0 || cfg.DataDir == "" {
		t.Fatal("defaults lost")
	}
}