package protocol

import (
	"bufio"
	"bytes"
	"testing"
)

func TestParseSimpleString(t *testing.T) {
	tests := []struct {
		input    string
		expected Status
	}{
		{"+OK\r\n", "OK"},
		{"+PONG\r\n", "PONG"},
		{"+\r\n", ""},
	}

	for _, tt := range tests {
		reader := bufio.NewReader(bytes.NewReader([]byte(tt.input)))
		val, err := Parse(reader)
		if err != nil {
			t.Errorf("Parse(%q) error: %v", tt.input, err)
			continue
		}
		status, ok := val.(Status)
		if !ok {
			t.Errorf("Parse(%q) got %T, want Status", tt.input, val)
			continue
		}
		if status != tt.expected {
			t.Errorf("Parse(%q) = %q, want %q", tt.input, status, tt.expected)
		}
	}
}

func TestParseError(t *testing.T) {
	input := "-ERR unknown command\r\n"
	reader := bufio.NewReader(bytes.NewReader([]byte(input)))
	val, err := Parse(reader)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}
	errVal, ok := val.(Error)
	if !ok {
		t.Fatalf("got %T, want Error", val)
	}
	if errVal.Message != "ERR unknown command" {
		t.Errorf("got %q, want 'ERR unknown command'", errVal.Message)
	}
}

func TestParseInteger(t *testing.T) {
	tests := []struct {
		input    string
		expected Int
	}{
		{":0\r\n", 0},
		{":12345\r\n", 12345},
		{":-100\r\n", -100},
	}

	for _, tt := range tests {
		reader := bufio.NewReader(bytes.NewReader([]byte(tt.input)))
		val, err := Parse(reader)
		if err != nil {
			t.Errorf("Parse(%q) error: %v", tt.input, err)
			continue
		}
		n, ok := val.(Int)
		if !ok {
			t.Errorf("Parse(%q) got %T, want Int", tt.input, val)
			continue
		}
		if n != tt.expected {
			t.Errorf("Parse(%q) = %d, want %d", tt.input, n, tt.expected)
		}
	}
}

func TestParseBulkString(t *testing.T) {
	tests := []struct {
		input    string
		expected []byte
	}{
		{"$5\r\nhello\r\n", []byte("hello")},
		{"$0\r\n\r\n", []byte("")},
		{"$-1\r\n", nil},
	}

	for _, tt := range tests {
		reader := bufio.NewReader(bytes.NewReader([]byte(tt.input)))
		val, err := Parse(reader)
		if err != nil {
			t.Errorf("Parse(%q) error: %v", tt.input, err)
			continue
		}
		if tt.expected == nil {
			if val != nil {
				t.Errorf("Parse(%q) = %v, want nil", tt.input, val)
			}
			continue
		}
		bulk, ok := val.(Bulk)
		if !ok {
			t.Errorf("Parse(%q) got %T, want Bulk", tt.input, val)
			continue
		}
		if string(bulk) != string(tt.expected) {
			t.Errorf("Parse(%q) = %q, want %q", tt.input, string(bulk), string(tt.expected))
		}
	}
}

func TestParseArray(t *testing.T) {
	input := "*2\r\n$3\r\nfoo\r\n$3\r\nbar\r\n"
	reader := bufio.NewReader(bytes.NewReader([]byte(input)))
	val, err := Parse(reader)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}
	arr, ok := val.(Array)
	if !ok {
		t.Fatalf("got %T, want Array", val)
	}
	if len(arr) != 2 {
		t.Errorf("array length = %d, want 2", len(arr))
	}
}

func TestParseEmptyArray(t *testing.T) {
	input := "*0\r\n"
	reader := bufio.NewReader(bytes.NewReader([]byte(input)))
	val, err := Parse(reader)
	if err != nil {
		t.Fatalf("Parse error: %v", err)
	}
	arr, ok := val.(Array)
	if !ok {
		t.Fatalf("got %T, want Array", val)
	}
	if len(arr) != 0 {
		t.Errorf("array length = %d, want 0", len(arr))
	}
}

func TestMakeStatus(t *testing.T) {
	result := MakeStatus("OK")
	expected := "+OK\r\n"
	if string(result) != expected {
		t.Errorf("MakeStatus() = %q, want %q", string(result), expected)
	}
}

func TestMakeInt(t *testing.T) {
	result := MakeInt(42)
	expected := ":42\r\n"
	if string(result) != expected {
		t.Errorf("MakeInt() = %q, want %q", string(result), expected)
	}
}

func TestMakeBulk(t *testing.T) {
	tests := []struct {
		input    []byte
		expected string
	}{
		{[]byte("hello"), "$5\r\nhello\r\n"},
		{[]byte(""), "$0\r\n\r\n"},
		{nil, "$-1\r\n"},
	}

	for _, tt := range tests {
		result := MakeBulk(tt.input)
		if string(result) != tt.expected {
			t.Errorf("MakeBulk(%q) = %q, want %q", tt.input, string(result), tt.expected)
		}
	}
}

func TestMakeMultiBulk(t *testing.T) {
	result := MakeMultiBulk([]Value{Bulk("message"), Bulk("mychannel"), Bulk("hello")})
	if len(result) == 0 {
		t.Error("MakeMultiBulk returned empty")
	}
}

func TestToBytes(t *testing.T) {
	tests := []struct {
		input    Value
		expected string
	}{
		{nil, "$-1\r\n"},
		{Status("OK"), "+OK\r\n"},
		{Int(42), ":42\r\n"},
		{Error{Message: "ERR"}, "-ERR\r\n"},
		{Bulk("test"), "$4\r\ntest\r\n"},
	}

	for _, tt := range tests {
		result := ToBytes(tt.input)
		if string(result) != tt.expected {
			t.Errorf("ToBytes(%v) = %q, want %q", tt.input, string(result), tt.expected)
		}
	}
}