#!/usr/bin/env bash
# imgDiagnose.sh - run imgStats / imgDiff on PNG or PPM inputs.
# PNGs are converted to PPM via ImageMagick into a sibling tmp file
# so the C tools never see the PNG and Claude never has to Read it.
#
# Usage:
#   imgDiagnose.sh stats <img>            # single-image text summary
#   imgDiagnose.sh diff <a> <b> [--ascii] # pairwise text diff
#
# Inputs may be .png, .ppm, or .pgm. PNG inputs are converted via
# `convert in.png ppm:tmpfile`. If two inputs differ in size, the
# larger one is resized to match the smaller (nearest neighbour) so
# differing PNG render scales (e.g. MAME 704x231 vs port 1120x768)
# can still be diffed without a manual pre-step.

set -euo pipefail

# Tools live in port/tools/<name>.c and are built by port/Makefile into
# port/bin/<name>. Resolve those paths from the script location.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PORT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
BIN_DIR="$PORT_DIR/bin"
TMP_DIR="$PORT_DIR/../tmp"
DIFF_BIN="$BIN_DIR/imgDiff"
STATS_BIN="$BIN_DIR/imgStats"

if [[ ! -x "$DIFF_BIN" || ! -x "$STATS_BIN" ]]; then
    (cd "$PORT_DIR" && make -s tools) >&2
fi

toPpm() {
    local in="$1"
    local out="$2"
    local ext="${in##*.}"
    if [[ "$ext" == "ppm" || "$ext" == "pgm" ]]; then
        cp "$in" "$out"
    else
        convert "$in" -depth 8 "ppm:$out"
    fi
}

cmd="${1:-}"
shift || true

case "$cmd" in
    stats)
        if [[ $# -ne 1 ]]; then
            echo "usage: imgDiagnose.sh stats <img>" >&2
            exit 2
        fi
        tmp=$(mktemp --tmpdir="$TMP_DIR" imgDiag.XXXXXX.ppm)
        trap 'rm -f "$tmp"' EXIT
        toPpm "$1" "$tmp"
        "$STATS_BIN" "$tmp"
        ;;
    diff)
        if [[ $# -lt 2 ]]; then
            echo "usage: imgDiagnose.sh diff <a> <b> [--ascii]" >&2
            exit 2
        fi
        a="$1"; shift
        b="$1"; shift
        extra=("$@")
        ta=$(mktemp --tmpdir="$TMP_DIR" imgDiagA.XXXXXX.ppm)
        tb=$(mktemp --tmpdir="$TMP_DIR" imgDiagB.XXXXXX.ppm)
        trap 'rm -f "$ta" "$tb"' EXIT
        toPpm "$a" "$ta"
        toPpm "$b" "$tb"
        # Match sizes: resize the larger to the smaller (nearest neighbour).
        wa=$(identify -format "%w" "$ta"); ha=$(identify -format "%h" "$ta")
        wb=$(identify -format "%w" "$tb"); hb=$(identify -format "%h" "$tb")
        if [[ "$wa" != "$wb" || "$ha" != "$hb" ]]; then
            if (( wa * ha >= wb * hb )); then
                convert "$ta" -filter point -resize "${wb}x${hb}!" -depth 8 "ppm:$ta"
            else
                convert "$tb" -filter point -resize "${wa}x${ha}!" -depth 8 "ppm:$tb"
            fi
        fi
        "$DIFF_BIN" "$ta" "$tb" "${extra[@]}"
        ;;
    *)
        cat >&2 <<EOF
usage:
  imgDiagnose.sh stats <img>
  imgDiagnose.sh diff <a> <b> [--ascii]
EOF
        exit 2
        ;;
esac