package main

import (
	"bufio"
	"strings"
	"testing"
)

func TestParseRequestLine(t *testing.T) {
	tests := []struct {
		name       string
		input      string
		wantMethod string
		wantUri    string
		wantProto  string
	}{
		{"basic GET", "GET / HTTP/1.1\n", "GET", "/", "HTTP/1.1"},
		{"POST with CRLF", "POST /path/resource HTTP/2.0\r\n", "POST", "/path/resource", "HTTP/2.0"},
		{"extra spaces", "  GET /spaced HTTP/1.0  \n", "GET", "/spaced", "HTTP/1.0"},
		{"invalid single token", "INVALIDLINE\n", "", "", ""},
		{"too many parts", "TOO MANY PARTS A B C\n", "", "", ""},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			m, u, p := parseRequestLine(tc.input)
			if m != tc.wantMethod || u != tc.wantUri || p != tc.wantProto {
				t.Fatalf("parseRequestLine(%q) = %q,%q,%q; want %q,%q,%q", tc.input, m, u, p, tc.wantMethod, tc.wantUri, tc.wantProto)
			}
		})
	}
}

func TestReadHeaders_Valid(t *testing.T) {
	// mix of CRLF and values with extra spaces, plus an invalid header line (no ':') which should be ignored
	req := "" +
		"GET /test HTTP/1.1\r\n" +
		"Host: example.com\r\n" +
		"X-Empty:    value with spaces   \r\n" +
		"InvalidHeaderLineWithoutColon\r\n" +
		"Connection: keep-alive\r\n" +
		"\r\n"

	r := bufio.NewReader(strings.NewReader(req))
	h := readHeaders(r)
	if h == nil {
		t.Fatal("expected headers, got nil")
	}

	if h.Method != "GET" || h.Uri != "/test" || h.Proto != "HTTP/1.1" {
		t.Fatalf("unexpected request line: got Method=%q Uri=%q Proto=%q", h.Method, h.Uri, h.Proto)
	}

	if got := h.KV["Host"]; got != "example.com" {
		t.Fatalf("Host header = %q; want %q", got, "example.com")
	}

	if got := h.KV["Connection"]; got != "keep-alive" {
		t.Fatalf("Connection header = %q; want %q", got, "keep-alive")
	}

	// value should be trimmed
	if got := h.KV["X-Empty"]; got != "value with spaces" {
		t.Fatalf("X-Empty header = %q; want trimmed %q", got, "value with spaces")
	}

	// invalid header line without ':' should be ignored
	if _, ok := h.KV["InvalidHeaderLineWithoutColon"]; ok {
		t.Fatalf("headers with no ':' should be ignored")
	}
}

func TestReadHeaders_EmptyReader_ReturnsNil(t *testing.T) {
	r := bufio.NewReader(strings.NewReader(""))
	h := readHeaders(r)
	if h != nil {
		t.Fatalf("expected nil for empty reader, got %v", h)
	}
}

func TestReadHeaders_MalformedRequestLine_ReturnsNil(t *testing.T) {
	r := bufio.NewReader(strings.NewReader("BADLINE\r\nHost: example.com\r\n\r\n"))
	h := readHeaders(r)
	if h != nil {
		t.Fatalf("expected nil for malformed request line, got %v", h)
	}
}

func TestReadHeaders_StopsAtFirstBlankLine(t *testing.T) {
	req := "" +
		"GET /abc HTTP/1.1\r\n" +
		"Header1: one\r\n" +
		"\r\n" +
		"Header2: should-not-be-read\r\n" // this should not be read as part of headers

	r := bufio.NewReader(strings.NewReader(req))
	h := readHeaders(r)
	if h == nil {
		t.Fatal("expected headers, got nil")
	}
	if _, ok := h.KV["Header2"]; ok {
		t.Fatalf("Header2 should not be present; headers reading should stop at blank line")
	}
}