package hlog

import (
	"os"
	"testing"

	"github.com/rs/zerolog"
)

func TestConfigFromEnv(t *testing.T) {
	tests := []struct {
		name    string
		envVars map[string]string
		want    *Config
		wantErr bool
		errMsg  string
	}{
		{
			name:    "default values",
			envVars: map[string]string{},
			want: &Config{
				LogLevel:    zerolog.InfoLevel,
				LogOutput:   "console",
				LogDir:      "",
				LogFileName: "",
				LogAppend:   true,
			},
			wantErr: false,
		},
		{
			name: "custom values",
			envVars: map[string]string{
				"LOG_LEVEL":     "debug",
				"LOG_OUTPUT":    "both",
				"LOG_DIR":       "/var/log/myapp",
				"LOG_FILE_NAME": "application.log",
				"LOG_APPEND":    "false",
			},
			want: &Config{
				LogLevel:    zerolog.DebugLevel,
				LogOutput:   "both",
				LogDir:      "/var/log/myapp",
				LogFileName: "application.log",
				LogAppend:   false,
			},
			wantErr: false,
		},
		{
			name: "file output mode",
			envVars: map[string]string{
				"LOG_LEVEL":     "warn",
				"LOG_OUTPUT":    "file",
				"LOG_DIR":       "/tmp/logs",
				"LOG_FILE_NAME": "test.log",
				"LOG_APPEND":    "true",
			},
			want: &Config{
				LogLevel:    zerolog.WarnLevel,
				LogOutput:   "file",
				LogDir:      "/tmp/logs",
				LogFileName: "test.log",
				LogAppend:   true,
			},
			wantErr: false,
		},
		{
			name: "invalid log level",
			envVars: map[string]string{
				"LOG_LEVEL":  "invalid",
				"LOG_OUTPUT": "console",
			},
			want:    nil,
			wantErr: true,
			errMsg:  "LogLevel",
		},
		{
			name: "invalid log output",
			envVars: map[string]string{
				"LOG_LEVEL":  "info",
				"LOG_OUTPUT": "invalid",
			},
			want:    nil,
			wantErr: true,
			errMsg:  "Invalid LOG_OUTPUT",
		},
		{
			name: "trace log level with defaults",
			envVars: map[string]string{
				"LOG_LEVEL":  "trace",
				"LOG_OUTPUT": "console",
			},
			want: &Config{
				LogLevel:    zerolog.TraceLevel,
				LogOutput:   "console",
				LogDir:      "",
				LogFileName: "",
				LogAppend:   true,
			},
			wantErr: false,
		},
		{
			name: "file output without LOG_DIR",
			envVars: map[string]string{
				"LOG_OUTPUT":    "file",
				"LOG_FILE_NAME": "test.log",
			},
			want:    nil,
			wantErr: true,
			errMsg:  "LOG_DIR not set",
		},
		{
			name: "file output without LOG_FILE_NAME",
			envVars: map[string]string{
				"LOG_OUTPUT": "file",
				"LOG_DIR":    "/tmp",
			},
			want:    nil,
			wantErr: true,
			errMsg:  "LOG_FILE_NAME not set",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// Clear all environment variables first
			os.Unsetenv("LOG_LEVEL")
			os.Unsetenv("LOG_OUTPUT")
			os.Unsetenv("LOG_DIR")
			os.Unsetenv("LOG_FILE_NAME")
			os.Unsetenv("LOG_APPEND")

			// Set test environment variables (only set if value provided)
			for k, v := range tt.envVars {
				os.Setenv(k, v)
			}
			
			// Cleanup after test
			defer func() {
				os.Unsetenv("LOG_LEVEL")
				os.Unsetenv("LOG_OUTPUT")
				os.Unsetenv("LOG_DIR")
				os.Unsetenv("LOG_FILE_NAME")
				os.Unsetenv("LOG_APPEND")
			}()

			got, err := ConfigFromEnv()

			if tt.wantErr {
				if err == nil {
					t.Errorf("ConfigFromEnv() expected error but got nil")
					return
				}
				if tt.errMsg != "" && err.Error() == "" {
					t.Errorf("ConfigFromEnv() error = %v, should contain %v", err, tt.errMsg)
				}
				return
			}

			if err != nil {
				t.Errorf("ConfigFromEnv() unexpected error = %v", err)
				return
			}

			if got.LogLevel != tt.want.LogLevel {
				t.Errorf("ConfigFromEnv() LogLevel = %v, want %v", got.LogLevel, tt.want.LogLevel)
			}
			if got.LogOutput != tt.want.LogOutput {
				t.Errorf("ConfigFromEnv() LogOutput = %v, want %v", got.LogOutput, tt.want.LogOutput)
			}
			if got.LogDir != tt.want.LogDir {
				t.Errorf("ConfigFromEnv() LogDir = %v, want %v", got.LogDir, tt.want.LogDir)
			}
			if got.LogFileName != tt.want.LogFileName {
				t.Errorf("ConfigFromEnv() LogFileName = %v, want %v", got.LogFileName, tt.want.LogFileName)
			}
			if got.LogAppend != tt.want.LogAppend {
				t.Errorf("ConfigFromEnv() LogAppend = %v, want %v", got.LogAppend, tt.want.LogAppend)
			}
		})
	}
}