package config

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

func TestWithERPEnvironmentFileUsesApprovedFallbackValues(t *testing.T) {
	path := writeERPEnvironmentFile(t, strings.Join([]string{
		"OTHER_TOOL_TOKEN=ignored",
		"CMROUBAO_SHUNYUNBAO_URL=https://erp.example.test",
		"CMROUBAO_SHUNYUNBAO_USERNAME=dotenv-user",
		"CMROUBAO_SHUNYUNBAO_PASSWORD='dotenv password #1'",
	}, "\n"))

	lookup, err := WithERPEnvironmentFile(path, func(string) (string, bool) {
		return "", false
	})
	if err != nil {
		t.Fatalf("WithERPEnvironmentFile() error = %v", err)
	}
	cfg, err := Load(lookup)
	if err != nil {
		t.Fatalf("Load() error = %v", err)
	}
	if cfg.ShunyunbaoURL != "https://erp.example.test" ||
		cfg.ShunyunbaoUsername != "dotenv-user" ||
		cfg.ShunyunbaoPassword != "dotenv password #1" {
		t.Fatalf(
			"ERP config = %#v",
			struct {
				URL      string
				Username string
				Password string
			}{cfg.ShunyunbaoURL, cfg.ShunyunbaoUsername, cfg.ShunyunbaoPassword},
		)
	}
	if _, exists := lookup("OTHER_TOOL_TOKEN"); exists {
		t.Fatal("unapproved .env value was exposed")
	}
}

func TestWithERPEnvironmentFileProcessEnvironmentTakesPriority(t *testing.T) {
	path := writeERPEnvironmentFile(t, strings.Join([]string{
		"CMROUBAO_SHUNYUNBAO_URL=https://dotenv.example.test",
		"CMROUBAO_SHUNYUNBAO_USERNAME=dotenv-user",
		"CMROUBAO_SHUNYUNBAO_PASSWORD=dotenv-password",
	}, "\n"))
	process := map[string]string{
		ShunyunbaoURLEnvironment:      "https://process.example.test",
		ShunyunbaoUsernameEnvironment: "process-user",
		ShunyunbaoPasswordEnvironment: "process-password",
	}
	lookup, err := WithERPEnvironmentFile(path, lookupMap(process))
	if err != nil {
		t.Fatalf("WithERPEnvironmentFile() error = %v", err)
	}
	cfg, err := Load(lookup)
	if err != nil {
		t.Fatalf("Load() error = %v", err)
	}
	if cfg.ShunyunbaoURL != process[ShunyunbaoURLEnvironment] ||
		cfg.ShunyunbaoUsername != process[ShunyunbaoUsernameEnvironment] ||
		cfg.ShunyunbaoPassword != process[ShunyunbaoPasswordEnvironment] {
		t.Fatalf("process values did not override .env values")
	}
}

func TestWithERPEnvironmentFileAllowsMissingFile(t *testing.T) {
	lookup, err := WithERPEnvironmentFile(
		filepath.Join(t.TempDir(), "missing.env"),
		lookupMap(nil),
	)
	if err != nil {
		t.Fatalf("WithERPEnvironmentFile() error = %v", err)
	}
	if _, exists := lookup(ShunyunbaoUsernameEnvironment); exists {
		t.Fatal("missing file provided a value")
	}
}

func TestWithERPEnvironmentFileRejectsInvalidContentWithoutLeakingValues(t *testing.T) {
	const secret = "must-not-appear-in-error"
	testCases := map[string]string{
		"invalid name": "not a name=" + secret,
		"duplicate": strings.Join([]string{
			"CMROUBAO_SHUNYUNBAO_USERNAME=" + secret,
			"CMROUBAO_SHUNYUNBAO_USERNAME=another",
		}, "\n"),
		"unknown app config": "CMROUBAO_AUTH_PASSWORD=" + secret,
		"unmatched quote":    "CMROUBAO_SHUNYUNBAO_PASSWORD='" + secret,
		"nul":                "CMROUBAO_SHUNYUNBAO_PASSWORD=" + secret + "\x00",
	}
	for name, contents := range testCases {
		t.Run(name, func(t *testing.T) {
			path := writeERPEnvironmentFile(t, contents)
			_, err := WithERPEnvironmentFile(path, lookupMap(nil))
			if err == nil {
				t.Fatal("WithERPEnvironmentFile() error = nil")
			}
			if strings.Contains(err.Error(), secret) {
				t.Fatalf("error leaked .env content: %v", err)
			}
		})
	}
}

func TestWithERPEnvironmentFileRejectsOversizedFile(t *testing.T) {
	path := writeERPEnvironmentFile(
		t,
		"CMROUBAO_SHUNYUNBAO_USERNAME="+
			strings.Repeat("x", maximumERPEnvironmentFileBytes),
	)
	_, err := WithERPEnvironmentFile(path, lookupMap(nil))
	if err == nil {
		t.Fatal("WithERPEnvironmentFile() error = nil")
	}
}

func writeERPEnvironmentFile(t *testing.T, contents string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), ".env")
	if err := os.WriteFile(path, []byte(contents), 0o600); err != nil {
		t.Fatalf("os.WriteFile() error = %v", err)
	}
	return path
}

func lookupMap(values map[string]string) LookupEnvironment {
	return func(name string) (string, bool) {
		value, exists := values[name]
		return value, exists
	}
}