package app

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

func TestTransportMigrateSingBoxDNSConfigMapLegacyUDP(t *testing.T) {
	root := map[string]any{
		"dns": map[string]any{
			"servers": []any{
				map[string]any{
					"tag":              "dns-direct",
					"address":          "1.1.1.1",
					"address_resolver": "dns-local",
					"address_strategy": "prefer_ipv4",
				},
			},
		},
	}
	changed, warns := transportMigrateSingBoxDNSConfigMap(root)
	if !changed {
		t.Fatalf("expected changed=true")
	}
	if len(warns) != 0 {
		t.Fatalf("unexpected warnings: %#v", warns)
	}

	dns := root["dns"].(map[string]any)
	servers := dns["servers"].([]any)
	srv := servers[0].(map[string]any)
	if strings.TrimSpace(asString(srv["type"])) != "udp" {
		t.Fatalf("expected type=udp, got %#v", srv["type"])
	}
	if strings.TrimSpace(asString(srv["server"])) != "1.1.1.1" {
		t.Fatalf("expected server=1.1.1.1, got %#v", srv["server"])
	}
	if _, ok := srv["address"]; ok {
		t.Fatalf("legacy address key must be removed")
	}
	if strings.TrimSpace(asString(srv["domain_resolver"])) != "dns-local" {
		t.Fatalf("expected domain_resolver migration, got %#v", srv["domain_resolver"])
	}
	if strings.TrimSpace(asString(srv["domain_strategy"])) != "prefer_ipv4" {
		t.Fatalf("expected domain_strategy migration, got %#v", srv["domain_strategy"])
	}
	if _, ok := srv["detour"]; ok {
		t.Fatalf("detour=direct should be removed in migrated config")
	}
}

func TestTransportMigrateSingBoxDNSConfigMapHTTPS(t *testing.T) {
	root := map[string]any{
		"dns": map[string]any{
			"servers": []any{
				map[string]any{
					"tag":     "dns-doh",
					"address": "https://1.1.1.1/dns-query",
				},
			},
		},
	}
	changed, warns := transportMigrateSingBoxDNSConfigMap(root)
	if !changed {
		t.Fatalf("expected changed=true")
	}
	if len(warns) != 0 {
		t.Fatalf("unexpected warnings: %#v", warns)
	}
	dns := root["dns"].(map[string]any)
	srv := dns["servers"].([]any)[0].(map[string]any)
	if strings.TrimSpace(asString(srv["type"])) != "https" {
		t.Fatalf("expected type=https, got %#v", srv["type"])
	}
	if strings.TrimSpace(asString(srv["server"])) != "1.1.1.1" {
		t.Fatalf("expected server=1.1.1.1, got %#v", srv["server"])
	}
	if _, ok := srv["path"]; ok {
		t.Fatalf("default /dns-query path should not be forced into config")
	}
}

func TestTransportMigrateSingBoxDNSConfigMapTypedServerDetourDirectRemoved(t *testing.T) {
	root := map[string]any{
		"dns": map[string]any{
			"servers": []any{
				map[string]any{
					"tag":    "dns-direct",
					"type":   "udp",
					"server": "1.1.1.1",
					"detour": "direct",
				},
			},
		},
	}
	changed, warns := transportMigrateSingBoxDNSConfigMap(root)
	if !changed {
		t.Fatalf("expected changed=true when removing direct detour")
	}
	if len(warns) != 0 {
		t.Fatalf("unexpected warnings: %#v", warns)
	}
	dns := root["dns"].(map[string]any)
	srv := dns["servers"].([]any)[0].(map[string]any)
	if _, ok := srv["detour"]; ok {
		t.Fatalf("detour should be removed for typed DNS server")
	}
}

func TestTransportSystemdBackendProvisionSingBoxDNSMigrationStrictFail(t *testing.T) {
	origRunner := transportRunCommand
	origUnitsDir := transportSystemdUnitsDir
	defer func() {
		transportRunCommand = origRunner
		transportSystemdUnitsDir = origUnitsDir
	}()

	transportSystemdUnitsDir = t.TempDir()
	transportRunCommand = func(_ time.Duration, _ string, _ ...string) (string, string, int, error) {
		return "", "", 0, nil
	}

	cfgDir := t.TempDir()
	cfg := filepath.Join(cfgDir, "singbox.json")
	if err := os.WriteFile(cfg, []byte("{broken-json"), 0o644); err != nil {
		t.Fatalf("write config: %v", err)
	}

	client := TransportClient{
		ID:   "sg-mig-strict",
		Kind: TransportClientSingBox,
		Config: map[string]any{
			"runner":                     "systemd",
			"unit":                       "sg-mig-strict.service",
			"bin":                        "/usr/bin/sing-box",
			"singbox_config_path":        cfg,
			"singbox_dns_migrate_legacy": true,
			"singbox_dns_migrate_strict": true,
		},
	}
	res := selectTransportBackend(client).Provision(client)
	if res.OK {
		t.Fatalf("expected strict migration failure, got %#v", res)
	}
	if res.Code != "TRANSPORT_BACKEND_SINGBOX_DNS_MIGRATE_FAILED" {
		t.Fatalf("unexpected code: %#v", res)
	}
}

func TestTransportSystemdBackendProvisionSingBoxDNSMigrationWritesBackup(t *testing.T) {
	origRunner := transportRunCommand
	origUnitsDir := transportSystemdUnitsDir
	defer func() {
		transportRunCommand = origRunner
		transportSystemdUnitsDir = origUnitsDir
	}()

	tmpDir := t.TempDir()
	transportSystemdUnitsDir = tmpDir
	transportRunCommand = func(_ time.Duration, name string, args ...string) (string, string, int, error) {
		cmd := name + " " + strings.Join(args, " ")
		if cmd == "systemctl daemon-reload" {
			return "", "", 0, nil
		}
		return "", "", 0, nil
	}

	cfgDir := t.TempDir()
	cfg := filepath.Join(cfgDir, "singbox.json")
	legacy := map[string]any{
		"dns": map[string]any{
			"servers": []any{
				map[string]any{
					"tag":     "dns-direct",
					"address": "1.1.1.1",
				},
			},
		},
	}
	raw, _ := json.Marshal(legacy)
	if err := os.WriteFile(cfg, raw, 0o644); err != nil {
		t.Fatalf("write config: %v", err)
	}

	client := TransportClient{
		ID:   "sg-mig-ok",
		Kind: TransportClientSingBox,
		Config: map[string]any{
			"runner":                     "systemd",
			"unit":                       "sg-mig-ok.service",
			"bin":                        "/usr/bin/sing-box",
			"singbox_config_path":        cfg,
			"singbox_dns_migrate_legacy": true,
		},
	}
	res := selectTransportBackend(client).Provision(client)
	if !res.OK {
		t.Fatalf("expected provision success, got %#v", res)
	}
	if !strings.Contains(strings.ToLower(res.Stdout), "dns-migrate:") {
		t.Fatalf("expected migration note in stdout, got %#v", res.Stdout)
	}
	if _, err := os.Stat(cfg + ".legacy-dns.bak"); err != nil {
		t.Fatalf("expected backup file, stat err=%v", err)
	}
	updatedRaw, err := os.ReadFile(cfg)
	if err != nil {
		t.Fatalf("read updated config: %v", err)
	}
	var updated map[string]any
	if err := json.Unmarshal(updatedRaw, &updated); err != nil {
		t.Fatalf("parse updated config: %v", err)
	}
	dns := updated["dns"].(map[string]any)
	srv := dns["servers"].([]any)[0].(map[string]any)
	if strings.TrimSpace(asString(srv["type"])) != "udp" {
		t.Fatalf("expected migrated type=udp, got %#v", srv["type"])
	}
	if _, ok := srv["address"]; ok {
		t.Fatalf("legacy address key should be removed after migration")
	}
}