ggplot with both `geom_vline` and `geom_hline`. Task: need separate legends

library(tidyverse)
library(lubridate)

y <- rnorm(100)

df <- tibble(y) %>% 
  mutate(os = factor(rep_len(1:5, 100)),
         date = seq(from = ymd('2013-01-01'), by = 1, length.out = 100))

ggplot(df, aes(x = date, y = y, colour = os)) +
  geom_line() +
  geom_vline(
    aes(xintercept = min(date), linetype = 'os 1'), 
    colour = 'red') +
  geom_vline(
    aes(xintercept = median(date), linetype = 'os 2'), 
    colour = 'blue') +
  geom_hline(
    aes(yintercept = 1, linetype = "dashed"),
    colour = "black"
  ) +
  scale_linetype_manual(
    name = 'lines',
    values = c('os 1' = 1, 'os 2' = 1),
    guide = guide_legend(override.aes = list(colour = c('red', 'blue')))) 

output:

What is wrong with output:

1. The geom_hline is missing.
2. The legend combines the vline and the hline to form a cross.

Correct output:

1. THe geom_hline should be drawn.
2. Need a separate legend for the vlines and hlines. i.e., lines in the vline legend should be vertical while lines in the hline legend should be horizontal.

This could be achieved by

1. Adding the hline to scale_linetype_manual
2. Making use of a custom key glyph as in this answer.

library(tidyverse)
library(lubridate)

set.seed(123)

y <- rnorm(100)

df <- tibble(y) %>% 
  mutate(os = factor(rep_len(1:5, 100)),
         date = seq(from = ymd('2013-01-01'), by = 1, length.out = 100))

draw_key_cust <- function(data, params, size) {
  if (data$colour %in% c("red", "blue"))
    draw_key_vpath(data, params, size)
  else
    draw_key_path(data, params, size)
}

ggplot(df, aes(x = date, y = y, colour = os)) +
  geom_line() +
  geom_vline(
    aes(xintercept = min(date), linetype = 'os 1'), 
    colour = 'red', key_glyph = "cust") +
  geom_vline(
    aes(xintercept = median(date), linetype = 'os 2'), 
    colour = 'blue', key_glyph = "cust") +
  geom_hline(
    aes(yintercept = 1, linetype = "dashed"), 
    colour = "black", key_glyph = "cust"
  ) +
  scale_linetype_manual(
    name = 'lines',
    values = c('os 1' = 1, 'os 2' = 1, dashed = 2),
    guide = guide_legend(override.aes = list(colour = c('red', 'blue', 'black'))))