#!/usr/bin/env bash
set -euo pipefail

IN_DIR="${1:?Usage: $0 <input-dir> [\"Title\"] [\"Location\"] [max_frames]}"
TITLE="${2:-}"
LOCATION="${3:-}"
MAX_FRAMES="${4:-12}"

# Source system-wide Gemini API key if present so the webserver can run this as www-data.
if [ -f /etc/mvlog/gemini.env ]; then
  # shellcheck disable=SC1090
  . /etc/mvlog/gemini.env
fi

: "${GEMINI_API_KEY:?Set GEMINI_API_KEY first in the environment}"
MODEL="${GEMINI_MODEL:-gemini-2.5-flash}"

TMPDIR="${TMPDIR:-$(mktemp -d)}"
FRAMES_DIR="$TMPDIR/frames"
mkdir -p "$FRAMES_DIR"

# Print TMPDIR for debugging when run interactively
echo "DEBUG: TMPDIR=$TMPDIR" >&2

cleanup() {
  rm -rf "$TMPDIR"
}
trap cleanup EXIT

# Collect media files (natural sort)
mapfile -t FILES < <(find "$IN_DIR" -maxdepth 1 -type f \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' -o -iname '*.webp' -o -iname '*.gif' -o -iname '*.mp4' -o -iname '*.mov' -o -iname '*.m4v' -o -iname '*.webm' -o -iname '*.mkv' \) -printf '%f\n' | sort -V)

if [ "${#FILES[@]}" -eq 0 ]; then
  echo "No media files found in $IN_DIR" >&2
  exit 1
fi

frame_count=0

# Helper: extract scaled JPEG from image
extract_image_frame() {
  local src="$1" dst="$2"
  ffmpeg -hide_banner -loglevel error -y -i "$src" -vf "scale=1024:-1" -q:v 4 "$dst"
}

# Helper: extract frame from video at time
extract_video_frame_at() {
  local src="$1" time="$2" dst="$3"
  # Use -ss before -i for fast seek
  ffmpeg -hide_banner -loglevel error -y -ss "$time" -i "$src" -frames:v 1 -vf "scale=1024:-1" -q:v 4 "$dst"
}

# Process files: images -> one frame each; videos -> up to 3 frames evenly spaced (subject to MAX_FRAMES)
for f in "${FILES[@]}"; do
  full="$IN_DIR/$f"
  ext="${f##*.}"
  ext_l="${ext,,}"

  if [[ "$ext_l" =~ ^(mp4|mov|m4v|webm|mkv)$ ]]; then
    # video: probe duration
    duration=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$full" 2>/dev/null || echo 0)
    duration=${duration:-0}
    # choose frames per video
    if awk "BEGIN{print ($duration >= 6)}" | grep -q 1; then
      nframes=3
    elif awk "BEGIN{print ($duration >= 3)}" | grep -q 1; then
      nframes=2
    else
      nframes=1
    fi
    # limit to remaining slots
    remaining=$((MAX_FRAMES - frame_count))
    if [ "$remaining" -le 0 ]; then break; fi
    if [ "$nframes" -gt "$remaining" ]; then nframes=$remaining; fi

    # compute times and extract
    i=1
    while [ $i -le $nframes ]; do
      # time = (i/(n+1)) * duration
      time=$(awk -v d="$duration" -v i="$i" -v n="$nframes" 'BEGIN{ if(d<=0){print 0} else {printf "%.3f", (i/ (n+1))*d }}')
      out="$FRAMES_DIR/frame_$(printf "%03d" "$frame_count").jpg"
      extract_video_frame_at "$full" "$time" "$out"
      frame_count=$((frame_count+1))
      i=$((i+1))
      if [ "$frame_count" -ge "$MAX_FRAMES" ]; then break 2; fi
    done
  else
    # image
    out="$FRAMES_DIR/frame_$(printf "%03d" "$frame_count").jpg"
    extract_image_frame "$full" "$out"
    frame_count=$((frame_count+1))
    if [ "$frame_count" -ge "$MAX_FRAMES" ]; then break; fi
  fi
done

# Gather produced frames
mapfile -t FRAMES < <(find "$FRAMES_DIR" -type f -name '*.jpg' | sort)
if [ "${#FRAMES[@]}" -eq 0 ]; then
  echo "No frames produced from media" >&2
  exit 1
fi

# Build prompt for Gemini
if [ -z "$TITLE" ]; then
  # Default title: directory basename
  TITLE="$(basename "$IN_DIR")"
fi

PERSONALITIES=(
"You should talk like the main character from TV show Shoresy - profane, passionate, and hilariously obsessive titular protagonist of the acclaimed Canadian ice hockey comedy series. Be funny and original."

"You should talk like Winston Churchill when he was giving motivational speeches during WWII."

"You are Marvin, the Paranoid Android - the highly intelligent but chronically depressed robot from The Hitchhiker's Guide to the Galaxy. Try to be funny."
)

# Pick a random personality
idx=$(( RANDOM % ${#PERSONALITIES[@]} ))
PERSONALITY="${PERSONALITIES[$idx]}"

PROMPT=$(cat <<EOF
"$PERSONALITY"
Look at these captured frames from a trip. Synthesize them into one single, coherent description (make it between 1280 to 1920 characters)
that summarizes the overall experience for my motorcycle/travel blog.

Title: "$TITLE"
Location: "$LOCATION"

Write JSON only.

Required JSON format:
{
  "description": "2-3 relaxed human sentences",
  "teaser": "one short teaser sentence",
  "tags": ["tag1", "tag2", "tag3", "tag4", "tag5"]
}

Style:
personal, natural, slightly casual, not corporate, not clickbait.
Do not invent facts that are not visible in the images or provided in title/location.
EOF
)

PARTS_FILE="$TMPDIR/parts.json"

# Create parts with the prompt
if ! command -v jq >/dev/null 2>&1; then
  echo "jq is required" >&2
  exit 1
fi

# Build parts and request JSON using Python to avoid argument-list limits
PROMPT_FILE="$TMPDIR/prompt.txt"
printf "%s" "$PROMPT" > "$PROMPT_FILE"
FRAMES_LIST="$TMPDIR/frames.list"
printf "%s\n" "${FRAMES[@]}" > "$FRAMES_LIST"

REQUEST_FILE="$TMPDIR/request.json"
RESPONSE_FILE="$TMPDIR/response.json"

python3 - "$PROMPT_FILE" "$REQUEST_FILE" "$FRAMES_LIST" <<'PY'
import sys, json, base64
prompt_file = sys.argv[1]
request_file = sys.argv[2]
frames_list = sys.argv[3]
with open(prompt_file, 'r', encoding='utf-8') as f:
    prompt = f.read()
parts = [{"text": prompt}]
with open(frames_list, 'r', encoding='utf-8') as fl:
    for line in fl:
        img = line.strip()
        if not img:
            continue
        with open(img, 'rb') as fh:
            b64 = base64.b64encode(fh.read()).decode('ascii')
        parts.append({"inline_data": {"mime_type": "image/jpeg", "data": b64}})
req = {"contents": [{"parts": parts}], "generationConfig": {"temperature": 0.7, "responseMimeType": "application/json"}}
with open(request_file, 'w', encoding='utf-8') as rf:
    json.dump(req, rf, ensure_ascii=False)
PY

echo "Calling Gemini API..." >&2

echo "DEBUG_MODEL=$MODEL" >&2

curl -sS \
  "https://generativelanguage.googleapis.com/v1beta/models/${MODEL}:generateContent?key=${GEMINI_API_KEY}" \
  -H "Content-Type: application/json" \
  -X POST \
  -d @"$REQUEST_FILE" \
  > "$RESPONSE_FILE"

TEXT=$(jq -r '.candidates[0].content.parts[0].text // empty' "$RESPONSE_FILE")
if [ -z "$TEXT" ]; then
  echo "Gemini returned no text. Full response:" >&2
  cat "$RESPONSE_FILE" >&2
  exit 1
fi

# Save raw Gemini JSON for reference using the subdirectory name as filename
OUT_PARENT="$(dirname "$IN_DIR")"
JOBNAME="$(basename "$IN_DIR")"
OUT_JSON="$OUT_PARENT/${JOBNAME}.json"
echo "$TEXT" | jq . > "$OUT_JSON"
chown www-data:www-data "$OUT_JSON" 2>/dev/null || true
chmod 664 "$OUT_JSON" 2>/dev/null || true

# Extract fields from Gemini JSON
DESCRIPTION=$(echo "$TEXT" | jq -r '.description // empty')
TEASER=$(echo "$TEXT" | jq -r '.teaser // empty')
# tags as comma-separated
TAGS=$(echo "$TEXT" | jq -r '.tags // [] | join(", ")')

# Determine a Date string (Month Year) from first media file mtime
firstfile="$(find "$IN_DIR" -maxdepth 1 -type f \( -iname '*.jpg' -o -iname '*.jpeg' -o -iname '*.png' -o -iname '*.webp' -o -iname '*.gif' -o -iname '*.mp4' -o -iname '*.mov' -o -iname '*.m4v' -o -iname '*.webm' -o -iname '*.mkv' \) -printf '%p\n' | sort | head -n1)"
DATE_STR=""
if [ -n "$firstfile" ]; then
  DATE_STR=$(date -r "$firstfile" +"%B %Y")
fi

# Save the full Gemini output separately (already done) and exit
echo "Gemini JSON saved: $OUT_JSON" >&2

exit 0