#!/bin/sh

# Default filenames
PROMPT_FILE="${1:-test_prompts.txt}"
RESULT_FILE="${2:-results.txt}"
EXECUTABLE="./lex"

# Ensure the executable exists and is runnable
if [ ! -x "$EXECUTABLE" ]; then
    echo "Error: Executable '$EXECUTABLE' not found or not executable." >&2
    exit 1
fi

# Ensure the prompt file exists
if [ ! -f "$PROMPT_FILE" ]; then
    echo "Error: Prompt file '$PROMPT_FILE' not found." >&2
    exit 1
fi

# Count valid prompts using POSIX awk to avoid ksh $(...) parenthetical syntax errors
total_prompts=$(awk '/^[[:space:]]*($|#)/ {next} {count++} END {print count+0}' "$PROMPT_FILE")

if [ "$total_prompts" -eq 0 ]; then
    echo "No valid prompts found in '$PROMPT_FILE'."
    exit 0
fi

# Create (or truncate) the result file at the start of the run
> "$RESULT_FILE"

# Create a 70-character horizontal rule: " -- " + 66 "-"
RULE=" -- "
i=0
while [ $i -lt 66 ]; do
    RULE="${RULE}-"
    i=$((i + 1))
done

echo "Starting evaluation: $total_prompts prompt(s) found."
echo "Writing results to: '$RESULT_FILE'"
echo "---------------------------------------------------"

current=0
first=1

# Temporary file to capture time / rusage output
TIME_LOG=$(mktemp /tmp/lex_time.XXXXXX)
trap 'rm -f "$TIME_LOG"' EXIT

# Process each prompt line by line
while IFS= read -r prompt || [ -n "$prompt" ]; do
    # Skip empty lines or comment lines starting with #
    case "$prompt" in
        ""|\#*) continue ;;
    esac

    current=$((current + 1))

    # Add delimiter before every prompt except the first in the results file
    if [ "$first" -eq 1 ]; then
        first=0
    else
        printf "%s\n\n" "$RULE" >> "$RESULT_FILE"
    fi

    # Log prompt header to the result file
    printf "PROMPT: %s\n\n" "$prompt" >> "$RESULT_FILE"

    # On OpenBSD, /usr/bin/time -lp outputs POSIX timings and rusage stats to stderr
    /usr/bin/time -lp "$EXECUTABLE" "$prompt" >> "$RESULT_FILE" 2> "$TIME_LOG"

    # Extract execution time and peak memory (maximum resident set size) from OpenBSD time output
    real_time=$(awk '/^real/ {print $2}' "$TIME_LOG")
	max_rss_mb=$(awk '/maximum resident set size/ {printf "%.2f", $1/1024}' "$TIME_LOG")

    # Format metrics summary line
    metrics_summary="ELAPSED: ${real_time}s | MAX RSS: ${max_rss_mb} MB"

    # Append metrics to result file
    printf "METRICS: %s\n\n" "$metrics_summary" >> "$RESULT_FILE"

    # Print real-time progress to terminal
    printf "[%d/%d] Done: %s (%s)\n" "$current" "$total_prompts" "$prompt" "$metrics_summary"

done < "$PROMPT_FILE"

echo "---------------------------------------------------"
echo "Done! Processed $total_prompts prompt(s)."