#!/bin/bash

###############################################################################
# Script Name: find_panoramas.sh
#
# Description:
#   Recursively scans a directory for JPG and PNG images and identifies
#   potential panorama images using multiple detection methods:
#
#     1. Aspect ratio < 0.5
#     2. Aspect ratio > 1.8
#     3. Width > 3 × Height
#
#   Images already tagged as "Panorama" are ignored.
#
#   Matching images are:
#     - Logged to a timestamped logfile
#     - Optionally copied to a review directory
#
# Requirements:
#   - Bash
#   - ImageMagick (identify)
#   - bc
#
# Usage:
#   ./find_panoramas.sh
#
###############################################################################

set -euo pipefail

IMG_DIR="/home/lucas/Pictures"
COPY_DIR="/home/lucas/Downloads"

PANORAMA_AR_LT="0.5"
PANORAMA_AR_HT="1.8"

DATE=$(date +"%Y%m%d_%H%M%S")
LOGFILE="${IMG_DIR}/panorama_${DATE}.log"

touch "$LOGFILE"

write_log() {
    echo "$@"
    echo "$@" >> "$LOGFILE"
}

# Verify dependencies
for cmd in identify bc; do
    command -v "$cmd" >/dev/null 2>&1 || {
        echo "Error: '$cmd' not found"
        exit 1
    }
done

find "$IMG_DIR" \
    \( -iname "*.jpg" -o -iname "*.jpeg" -o -iname "*.png" \) \
    -print0 |
while IFS= read -r -d '' img; do

    # Get dimensions
    dimensions=$(identify -format "%wx%h" "$img" 2>/dev/null) || {
        write_log "Skipping invalid image: $img"
        continue
    }

    width=${dimensions%x*}
    height=${dimensions#*x}

    # Avoid divide-by-zero
    [[ "$height" -eq 0 ]] && continue

    # Calculate aspect ratio
    aspect_ratio=$(echo "scale=4; $height / $width" | bc -l)

    # Skip images already marked Panorama
    if identify -verbose "$img" 2>/dev/null | grep -q "Panorama"; then
        continue
    fi

    panorama=false

    # Aspect-ratio checks
    if (( $(echo "$aspect_ratio < $PANORAMA_AR_LT" | bc -l) )); then
        panorama=true
    elif (( $(echo "$aspect_ratio > $PANORAMA_AR_HT" | bc -l) )); then
        panorama=true
    fi

    # Width > 3 × Height check
    if (( width > height * 3 )); then
        panorama=true
    fi

    if [[ "$panorama" == true ]]; then

        write_log "PANORAMA | ${dimensions} | AR=${aspect_ratio} | ${img}"

        # Copy for manual review
        cp -n "$img" "$COPY_DIR/" 2>/dev/null || true
    fi

done

write_log "Scan complete."