#!/usr/bin/env bash
# Resolve pipeline input from CLI arg, sources.list index, or env SOURCE_URL.
set -euo pipefail

# shellcheck disable=SC1091
source "$(dirname "${BASH_SOURCE[0]}")/common.sh"

SOURCE_URL=""
SOURCE_FMT=""
SOURCE_VIDEO_STREAM="v:0"
SOURCE_AUDIO_STREAM="a:0"
AUDIO_INPUT_ARGS=()
USE_YTDLP=0

is_page_url() {
  local url="$1"
  [[ "$url" =~ ^https?:// ]] || return 1
  [[ "$url" =~ \.(m3u8|mpd|mp4|mkv|mov|ts|flv)(\?|$) ]] && return 1
  [[ -f "$url" ]] && return 1
  return 0
}

resolve_source() {
  local arg="${1:-}"
  SOURCE_URL="${SOURCE_URL:-}"
  SOURCE_FMT=""

  if [[ -n "${SOURCE_URL}" ]]; then
    :
  elif [[ -n "${arg}" && -f "${arg}" && "${arg}" != *".list" ]]; then
    SOURCE_URL="${arg}"
  elif [[ -n "${arg}" && "${arg}" =~ ^https?:// ]]; then
    SOURCE_URL="${arg}"
  elif [[ -n "${arg}" && "${arg}" =~ ^[0-9]+$ ]]; then
    if [[ ! -f "${SOURCES_LIST}" ]]; then
      die "sources list missing: ${SOURCES_LIST} (copy sources.example.list)"
    fi
    local line
    line="$(sed -n "${arg}p" "${SOURCES_LIST}" | sed 's/#.*//' | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
    [[ -n "${line}" ]] || die "no source on line ${arg} of ${SOURCES_LIST}"
    SOURCE_URL="$(awk '{print $1}' <<<"${line}")"
    SOURCE_FMT="$(awk '{print $2}' <<<"${line}")"
  elif [[ -f "${SOURCES_LIST}" ]]; then
    local line
    line="$(grep -v '^[[:space:]]*#' "${SOURCES_LIST}" | grep -v '^[[:space:]]*$' | head -1)"
    SOURCE_URL="$(awk '{print $1}' <<<"${line}")"
    SOURCE_FMT="$(awk '{print $2}' <<<"${line}")"
  else
    die "usage: pass URL, file path, or 1-based index into ${SOURCES_LIST}"
  fi

  [[ -n "${SOURCE_URL}" ]] || die "empty source URL"

  if [[ -n "${AUDIO_SOURCE:-}" ]]; then
    read_rate_flag
    AUDIO_INPUT_ARGS=("${RE_FLAG[@]}" -thread_queue_size "${THREAD_QUEUE_SIZE}" -i "${AUDIO_SOURCE}")
    SOURCE_AUDIO_STREAM="a:0"
  fi

  if [[ "${YTDLP_ENABLED}" == "1" ]] && is_page_url "${SOURCE_URL}"; then
    USE_YTDLP=1
  fi

  echo "${SOURCE_URL}" > "${ROOT}/.current_source"
  log "source: ${SOURCE_URL} (ytdlp=${USE_YTDLP})"
}

ytdlp_auth_args() {
  local auth="${ROOT}/config/yt-dlp.auth.env"
  if [[ -f "${auth}" ]]; then
    # shellcheck disable=SC1090
    source "${auth}"
  fi
  local args=()
  [[ -n "${YTDLP_USERNAME:-}" ]] && args+=(--username "${YTDLP_USERNAME}")
  [[ -n "${YTDLP_PASSWORD:-}" ]] && args+=(--password "${YTDLP_PASSWORD}")
  [[ -n "${YTDLP_NETRC:-}" ]] && args+=(--netrc)
  [[ -n "${YTDLP_EXTRA_ARGS:-}" ]] && args+=(${YTDLP_EXTRA_ARGS})
  printf '%s\n' "${args[@]}"
}

build_ytdlp_pipeline() {
  local fmt_args=()
  [[ -n "${SOURCE_FMT}" ]] && fmt_args=(-f "${SOURCE_FMT}")
  mapfile -t auth < <(ytdlp_auth_args)

  printf '%s\0' "${YTDLP_BIN}" \
    -o - --no-part --no-live-from-start --no-write-subs --no-embed-subs \
    --remux-video mkv --merge-output-format mkv --no-audio-multistreams \
    --geo-bypass --ignore-errors --hls-use-mpegts \
    "${auth[@]}" \
    "${fmt_args[@]}" \
    "${SOURCE_URL}"
}

# Returns ffmpeg input argv: either direct -i URL or pipe from yt-dlp.
build_primary_input() {
  read_rate_flag
  if [[ "${USE_YTDLP}" == "1" ]]; then
    require_cmd "${YTDLP_BIN}"
    printf '%s\0' pipe
    printf '%s\0' -thread_queue_size "${THREAD_QUEUE_SIZE}" -i pipe:0
    return
  fi

  local url="${SOURCE_URL}"
  if [[ "${url}" == *.jpg || "${url}" == *.jpeg || "${url}" == *.png ]]; then
    printf '%s\0' direct
    printf '%s\0' "${RE_FLAG[@]}" -thread_queue_size "${THREAD_QUEUE_SIZE}" \
      -loop 1 -i "${url}" -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=48000
    return
  fi

  printf '%s\0' direct
  printf '%s\0' "${RE_FLAG[@]}" -thread_queue_size "${THREAD_QUEUE_SIZE}" \
    -reconnect_on_network_error 1 -reconnect_streamed 1 -reconnect_delay_max 5 \
    -i "${url}"
}