package config

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

func writeTemp(t *testing.T, body string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "warp.yaml")
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatal(err)
	}
	return path
}

func TestLoadAppliesDefaults(t *testing.T) {
	path := writeTemp(t, "version: 1\nglobal:\n  server_name: warp.example\n")

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if got, want := cfg.Listen.Address, ":8008"; got != want {
		t.Errorf("listen.address = %q, want %q", got, want)
	}
	if got, want := cfg.Database.Driver, "sqlite"; got != want {
		t.Errorf("database.driver = %q, want %q", got, want)
	}
	if cfg.Federation.Enabled {
		t.Error("federation must default to disabled")
	}
	if !cfg.Federation.AllowRuntimeToggle {
		t.Error("federation.allow_runtime_toggle must default to true")
	}
	if got, want := cfg.ClientBaseURL(), "https://warp.example"; got != want {
		t.Errorf("ClientBaseURL() = %q, want %q", got, want)
	}
	if cfg.Path() == "" {
		t.Error("Path() must record the file the config came from")
	}
}

func TestLoadRejectsUnknownFields(t *testing.T) {
	path := writeTemp(t, "version: 1\nglobal:\n  server_name: warp.example\n  srever_name: typo\n")

	_, err := Load(path)
	if err == nil {
		t.Fatal("expected an error for an unknown field")
	}
	if !strings.Contains(err.Error(), "srever_name") {
		t.Errorf("error should name the offending field, got: %v", err)
	}
}

func TestValidateCollectsEveryProblem(t *testing.T) {
	cfg := Default()
	cfg.Global.ServerName = ""
	cfg.Database.Driver = "mysql"
	cfg.Logging.Level = "chatty"

	err := cfg.Validate()
	if err == nil {
		t.Fatal("expected validation to fail")
	}
	for _, want := range []string{"global.server_name", "database.driver", "logging.level"} {
		if !strings.Contains(err.Error(), want) {
			t.Errorf("error should mention %s, got: %v", want, err)
		}
	}
}

func TestApplyEnvOverrides(t *testing.T) {
	cfg := Default()
	cfg.Global.ServerName = "from-yaml.example"
	cfg.Federation.Allowlist = []string{"a.example"}

	env := map[string]string{
		"WARP_SERVER_NAME":                "from-env.example",
		"WARP_FEDERATION_ENABLED":         "true",
		"WARP_FEDERATION_ALLOWLIST":       "b.example, c.example",
		"WARP_DB_MAX_OPEN_CONNS":          "42",
		"WARP_SHUTDOWN_TIMEOUT":           "5s",
		"WARP_WELL_KNOWN_CLIENT_BASE_URL": "https://matrix.example",
	}
	if err := ApplyEnv(cfg, func(k string) string { return env[k] }); err != nil {
		t.Fatalf("ApplyEnv: %v", err)
	}

	if got, want := cfg.Global.ServerName, "from-env.example"; got != want {
		t.Errorf("server_name = %q, want %q", got, want)
	}
	if !cfg.Federation.Enabled {
		t.Error("federation.enabled should have been overridden to true")
	}
	if got, want := strings.Join(cfg.Federation.Allowlist, ","), "b.example,c.example"; got != want {
		t.Errorf("allowlist = %q, want %q", got, want)
	}
	if got, want := cfg.Database.MaxOpenConns, 42; got != want {
		t.Errorf("max_open_conns = %d, want %d", got, want)
	}
	if got, want := cfg.Listen.ShutdownTimeout, 5*time.Second; got != want {
		t.Errorf("shutdown_timeout = %s, want %s", got, want)
	}
	if got, want := cfg.ClientBaseURL(), "https://matrix.example"; got != want {
		t.Errorf("ClientBaseURL() = %q, want %q", got, want)
	}
}

func TestApplyEnvRejectsMalformedValues(t *testing.T) {
	cfg := Default()
	err := ApplyEnv(cfg, func(k string) string {
		if k == "WARP_FEDERATION_ENABLED" {
			return "yes-please"
		}
		return ""
	})
	if err == nil || !strings.Contains(err.Error(), "WARP_FEDERATION_ENABLED") {
		t.Fatalf("expected an error naming the variable, got: %v", err)
	}
}

func TestApplyEnvEmptyListSentinel(t *testing.T) {
	cfg := Default()
	cfg.ClientAPI.CORSAllowedOrigins = []string{"*"}
	if err := ApplyEnv(cfg, func(k string) string {
		if k == "WARP_CORS_ALLOWED_ORIGINS" {
			return "-"
		}
		return ""
	}); err != nil {
		t.Fatalf("ApplyEnv: %v", err)
	}
	if len(cfg.ClientAPI.CORSAllowedOrigins) != 0 {
		t.Errorf("expected the list to be cleared, got %v", cfg.ClientAPI.CORSAllowedOrigins)
	}
}

// TestExampleConfigIsValid keeps warp.yaml.example honest: it must parse
// with unknown fields rejected and pass validation as shipped.
func TestExampleConfigIsValid(t *testing.T) {
	path := filepath.Join("..", "..", "..", "warp.yaml.example")
	if _, err := os.Stat(path); err != nil {
		t.Skipf("example config not found: %v", err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("warp.yaml.example does not load: %v", err)
	}
	if cfg.Federation.Enabled {
		t.Error("the shipped example must keep federation off")
	}
	if cfg.Registration.Enabled {
		t.Error("the shipped example must keep registration off")
	}
	if cfg.Database.Driver != "sqlite" {
		t.Errorf("example driver = %q, want sqlite", cfg.Database.Driver)
	}
	if cfg.Sync.Presence {
		t.Error("the shipped example must keep presence off (PLAN.md open question 3)")
	}
	// A zero here would mean the example omitted the section and the
	// validation below is passing on the defaults rather than on the file.
	if cfg.Sync.TypingTimeout == 0 || cfg.Sync.LongPollTimeout == 0 {
		t.Error("the shipped example must set the sync timeouts")
	}
	if cfg.ClientAPI.RateLimit.Sync.Burst == 0 {
		t.Error("the shipped example must set the sync rate-limit bucket")
	}
}