package ircserver_test

import (
	"testing"

	"git.eeqj.de/sneak/neoirc/internal/ircserver"
)

//nolint:funlen // table-driven test
func TestParseMessage(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name    string
		input   string
		want    *ircserver.Message
		wantNil bool
	}{
		{
			name:    "empty",
			input:   "",
			want:    nil,
			wantNil: true,
		},
		{
			name:  "simple command",
			input: "PING",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "PING",
				Params:  nil,
			},
			wantNil: false,
		},
		{
			name:  "command with one param",
			input: "NICK alice",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "NICK",
				Params:  []string{"alice"},
			},
			wantNil: false,
		},
		{
			name:  "command case insensitive",
			input: "nick Alice",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "NICK",
				Params:  []string{"Alice"},
			},
			wantNil: false,
		},
		{
			name:  "privmsg with trailing",
			input: "PRIVMSG #general :hello world",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "PRIVMSG",
				Params:  []string{"#general", "hello world"},
			},
			wantNil: false,
		},
		{
			name:  "with prefix",
			input: ":server.example.com 001 alice :Welcome to IRC",
			want: &ircserver.Message{
				Prefix:  "server.example.com",
				Command: "001",
				Params:  []string{"alice", "Welcome to IRC"},
			},
			wantNil: false,
		},
		{
			name:  "user command",
			input: "USER alice 0 * :Alice Smith",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "USER",
				Params: []string{
					"alice", "0", "*", "Alice Smith",
				},
			},
			wantNil: false,
		},
		{
			name:  "join channel",
			input: "JOIN #general",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "JOIN",
				Params:  []string{"#general"},
			},
			wantNil: false,
		},
		{
			name:  "quit with trailing",
			input: "QUIT :leaving now",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "QUIT",
				Params:  []string{"leaving now"},
			},
			wantNil: false,
		},
		{
			name:  "quit without reason",
			input: "QUIT",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "QUIT",
				Params:  nil,
			},
			wantNil: false,
		},
		{
			name:  "mode query",
			input: "MODE #general",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "MODE",
				Params:  []string{"#general"},
			},
			wantNil: false,
		},
		{
			name:  "kick with reason",
			input: "KICK #general bob :misbehaving",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "KICK",
				Params: []string{
					"#general", "bob", "misbehaving",
				},
			},
			wantNil: false,
		},
		{
			name:  "empty trailing",
			input: "PRIVMSG #general :",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "PRIVMSG",
				Params:  []string{"#general", ""},
			},
			wantNil: false,
		},
		{
			name:  "pass command",
			input: "PASS mysecret",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "PASS",
				Params:  []string{"mysecret"},
			},
			wantNil: false,
		},
		{
			name:  "ping with server",
			input: "PING :irc.example.com",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "PING",
				Params:  []string{"irc.example.com"},
			},
			wantNil: false,
		},
		{
			name:  "topic with trailing spaces",
			input: "TOPIC #general :Welcome to the channel!",
			want: &ircserver.Message{
				Prefix:  "",
				Command: "TOPIC",
				Params: []string{
					"#general",
					"Welcome to the channel!",
				},
			},
			wantNil: false,
		},
	}

	for _, testCase := range tests {
		t.Run(testCase.name, func(t *testing.T) {
			t.Parallel()

			got := ircserver.ParseMessage(testCase.input)
			if testCase.wantNil {
				if got != nil {
					t.Fatalf("expected nil, got %+v", got)
				}

				return
			}

			if got == nil {
				t.Fatal("expected non-nil message")
			}

			if got.Prefix != testCase.want.Prefix {
				t.Errorf(
					"prefix: got %q, want %q",
					got.Prefix, testCase.want.Prefix,
				)
			}

			if got.Command != testCase.want.Command {
				t.Errorf(
					"command: got %q, want %q",
					got.Command, testCase.want.Command,
				)
			}

			if len(got.Params) != len(testCase.want.Params) {
				t.Fatalf(
					"params length: got %d, want %d (%v vs %v)",
					len(got.Params),
					len(testCase.want.Params),
					got.Params,
					testCase.want.Params,
				)
			}

			for i, p := range got.Params {
				if p != testCase.want.Params[i] {
					t.Errorf(
						"param[%d]: got %q, want %q",
						i, p, testCase.want.Params[i],
					)
				}
			}
		})
	}
}

func TestFormatMessage(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name    string
		prefix  string
		command string
		params  []string
		want    string
	}{
		{
			name:    "simple command",
			prefix:  "",
			command: "PING",
			params:  nil,
			want:    "PING",
		},
		{
			name:    "with prefix",
			prefix:  "server",
			command: "PONG",
			params:  []string{"server"},
			want:    ":server PONG server",
		},
		{
			name:    "privmsg with trailing",
			prefix:  "alice!alice@host",
			command: "PRIVMSG",
			params:  []string{"#general", "hello world"},
			want:    ":alice!alice@host PRIVMSG #general :hello world",
		},
		{
			name:    "numeric reply",
			prefix:  "server",
			command: "001",
			params:  []string{"alice", "Welcome to IRC"},
			want:    ":server 001 alice :Welcome to IRC",
		},
		{
			name:    "empty trailing",
			prefix:  "server",
			command: "PRIVMSG",
			params:  []string{"#chan", ""},
			want:    ":server PRIVMSG #chan :",
		},
	}

	for _, testCase := range tests {
		t.Run(testCase.name, func(t *testing.T) {
			t.Parallel()

			got := ircserver.FormatMessage(
				testCase.prefix, testCase.command, testCase.params...,
			)
			if got != testCase.want {
				t.Errorf("got %q, want %q", got, testCase.want)
			}
		})
	}
}

func TestParseFormatRoundTrip(t *testing.T) {
	t.Parallel()

	// Round-trip only works for lines where the last
	// parameter either contains a space (gets ':' prefix
	// on format) or is a non-trailing single token.
	lines := []string{
		"PING",
		"NICK alice",
		"PRIVMSG #general :hello world",
		"JOIN #general",
		"MODE #general",
	}

	for _, line := range lines {
		msg := ircserver.ParseMessage(line)
		if msg == nil {
			t.Fatalf("failed to parse: %q", line)
		}

		formatted := ircserver.FormatMessage(
			msg.Prefix, msg.Command, msg.Params...,
		)
		if formatted != line {
			t.Errorf(
				"round-trip failed: input %q, got %q",
				line, formatted,
			)
		}
	}
}