#!/usr/bin/env bash
set -euo pipefail
script_dir="$(cd "$(dirname "$0")" && pwd)"
# Source SDK (MCP_SDK is set by the framework when running tools)
# shellcheck source=../../../../../sdk/tool-sdk.sh disable=SC1091
source "${MCP_SDK:?MCP_SDK environment variable not set}/tool-sdk.sh"
# shellcheck source=../../lib/roots.sh disable=SC1091
source "${script_dir}/../../lib/roots.sh"
json_bin="${MCPBASH_JSON_TOOL_BIN:-}"
if [[ -z "${json_bin}" ]] || ! command -v "${json_bin}" >/dev/null 2>&1; then
mcp_fail -32603 "JSON tooling unavailable for argument parsing"
fi
input_path="$(mcp_args_get '.input // empty' 2>/dev/null || true)"
output_path="$(mcp_args_get '.output // empty' 2>/dev/null || true)"
preset="$(mcp_args_get '.preset // empty' 2>/dev/null || true)"
start_time="$(mcp_args_get '.start_time // empty' 2>/dev/null || true)"
duration="$(mcp_args_get '.duration // empty' 2>/dev/null || true)"
if [[ -z "${input_path}" ]] && [[ $# -ge 1 ]]; then
input_path="$1"
fi
if [[ -z "${output_path}" ]] && [[ $# -ge 2 ]]; then
output_path="$2"
fi
if [[ -z "${preset}" ]] && [[ $# -ge 3 ]]; then
preset="$3"
fi
if [[ -z "${start_time}" ]] && [[ $# -ge 4 ]]; then
start_time="$4"
fi
if [[ -z "${duration}" ]] && [[ $# -ge 5 ]]; then
duration="$5"
fi
if [[ -z "${input_path}" ]] || [[ -z "${output_path}" ]] || [[ -z "${preset}" ]]; then
mcp_fail_invalid_args "Missing required arguments: input, output, preset"
fi
full_input="$(mcp_ffmpeg_resolve_path "${input_path}" "read")"
full_output="$(mcp_ffmpeg_resolve_path "${output_path}" "write")"
# Validation: Input exists → Tool Execution Error (LLM can choose a different file)
if [[ ! -f "${full_input}" ]]; then
mcp_result_error "$(
mcp_json_obj \
error "Input file not found" \
input "${input_path}" \
hint "Check the file exists and is within allowed media roots"
)"
fi
# Validation: Output collision with elicitation-based confirmation
if [[ -f "${full_output}" ]]; then
if [[ "${MCP_ELICIT_SUPPORTED:-0}" != "1" ]]; then
# Tool Execution Error: LLM can choose a different output path
mcp_result_error "$(
mcp_json_obj \
error "Output file already exists" \
output "${output_path}" \
hint "Choose a different output path or enable elicitation to confirm overwrite"
)"
fi
if [[ -z "${json_bin}" ]]; then
mcp_fail -32603 "JSON tooling unavailable for elicitation parsing"
fi
overwrite_resp="$(mcp_elicit_confirm "Output ${output_path} exists. Overwrite?")"
overwrite_fields="$("${json_bin}" -r '[.action, (.content.confirmed // false)] | @tsv' <<<"${overwrite_resp}")"
overwrite_action="${overwrite_fields%%$'\t'*}"
overwrite_confirmed="${overwrite_fields#*$'\t'}"
if [[ "${overwrite_action}" != "accept" ]] || [[ "${overwrite_confirmed}" != "true" ]]; then
# Tool Execution Error: User declined, LLM can try different output
mcp_result_error "$(
mcp_json_obj \
error "Overwrite declined" \
output "${output_path}" \
hint "Choose a different output path"
)"
fi
fi
# Determine ffmpeg args based on preset (separate input vs output options for ordering)
global_opts=("-hide_banner")
input_opts=()
output_opts=("-y")
if [[ -n "${start_time}" ]]; then
input_opts+=("-ss" "${start_time}")
fi
if [[ -n "${duration}" ]]; then
input_opts+=("-t" "${duration}")
fi
case "${preset}" in
"1080p")
output_opts+=("-c:v" "libx264" "-preset" "fast" "-crf" "23" "-vf" "scale=-2:1080" "-c:a" "aac" "-b:a" "128k")
;;
"720p")
output_opts+=("-c:v" "libx264" "-preset" "fast" "-crf" "23" "-vf" "scale=-2:720" "-c:a" "aac" "-b:a" "128k")
;;
"audio-only")
output_opts+=("-vn" "-c:a" "libmp3lame" "-b:a" "192k")
;;
"gif")
# Complex filter for high quality GIF
output_opts+=("-vf" "fps=10,scale=320:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse")
;;
*)
# Tool Execution Error: LLM can choose a valid preset
mcp_result_error "$(
mcp_json_obj \
error "Invalid preset" \
preset "${preset}" \
hint "Valid presets: 1080p, 720p, audio-only, gif"
)"
;;
esac
# Get total duration in microseconds for progress calculation
total_duration_us=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${full_input}" | awk '{print int($1 * 1000000)}')
if [[ -z "${total_duration_us}" ]] || [[ "${total_duration_us}" -eq 0 ]]; then
# Fallback if duration unknown
total_duration_us=1
fi
# Run ffmpeg with a dedicated progress pipe so we can track cancellation and exit codes accurately.
mcp_progress 0 "Starting transcoding..."
fifo_dir="$(mktemp -d "${TMPDIR:-/tmp}/mcp-ffmpeg-progress.XXXXXX")"
progress_fifo="${fifo_dir}/progress.fifo"
mkfifo "${progress_fifo}"
mcp_ffmpeg_cleanup_fifo() {
rm -rf "${fifo_dir}"
}
trap mcp_ffmpeg_cleanup_fifo EXIT INT TERM
ffmpeg "${global_opts[@]}" "${input_opts[@]}" -i "${full_input}" -progress "${progress_fifo}" "${output_opts[@]}" "${full_output}" &
ffmpeg_pid=$!
while IFS= read -r line; do
key=${line%%=*}
value=${line#*=}
if [[ "$key" == "out_time_us" ]]; then
current_us=$value
if [[ "${total_duration_us}" -gt 0 ]]; then
pct=$((current_us * 100 / total_duration_us))
if [[ $pct -gt 100 ]]; then
pct=100
fi
mcp_progress "${pct}" "Transcoding... ${pct}%"
fi
fi
if mcp_is_cancelled; then
kill "${ffmpeg_pid}" 2>/dev/null || true
wait "${ffmpeg_pid}" 2>/dev/null || true
rm -f "${full_output}"
mcp_fail -32001 "Cancelled"
fi
done <"${progress_fifo}"
wait_status=0
if ! wait "${ffmpeg_pid}"; then
wait_status=$?
fi
rm -f "${progress_fifo}"
trap - EXIT INT TERM
if [[ "${wait_status}" -ne 0 ]]; then
rm -f "${full_output}"
mcp_fail -32603 "Transcode failed (ffmpeg exit ${wait_status})"
fi
mcp_result_success "$(mcp_json_obj message "Transcoding complete: ${output_path}")"
