#!/bin/bash

# Function to show usage
usage() {
    echo "Usage: $0 [-l] [write|validate]"
    echo "  -l   Use local input files (e.g., day01input.txt)"
    exit 1
}

# Parse arguments
LOCAL_MODE=0
while getopts ":l" opt; do
    case $opt in
        l) LOCAL_MODE=1 ;;
        *) usage ;;
    esac
done
shift $((OPTIND - 1))

if [[ $# -ne 1 ]]; then
    usage
fi

MODE=$1

# Function to fetch input
fetch_input() {
    local script=$1
    local dayname
    dayname=$(basename "$script" .kts | tr 'a-z' 'A-Z')
    if [[ $LOCAL_MODE -eq 1 ]]; then
        # Fetch input from local files
        local input_file="${dayname,,}input.txt"
        if [[ -f "$input_file" ]]; then
            cat "$input_file"
        else
            echo "Error: Local input file $input_file not found" >&2
            exit 1
        fi
    else
        # Fetch input from environment variable
        local env_var="${dayname}INPUT"
        if [[ -z "${!env_var}" ]]; then
            echo "Error: Environment variable $env_var not set" >&2
            exit 1
        fi
        echo "${!env_var}"
    fi
}

# Write mode
if [[ "$MODE" == "write" ]]; then
    echo "Running in write mode..."

    for script in *.kts; do
        test_file="${script}.testvalue"

        echo "Processing $script..."
        input=$(fetch_input "$script")
        output=$(echo "$input" | kotlin "$script" 2>&1)

        if [[ -f "$test_file" ]]; then
            if [[ "$output" == "$(cat "$test_file")" ]]; then
                echo "No change: $script"
            else
                echo "Output changed for $script"
                diff -u "$test_file" <(echo "$output")
                read -p "Update test value? (y/n) " update
                if [[ "$update" == "y" ]]; then
                    echo "$output" > "$test_file"
                    echo "Updated $test_file"
                fi
            fi
        else
            echo "$output" > "$test_file"
            echo "Created $test_file"
        fi
    done

    for test_file in *.kts.testvalue; do
        script="${test_file%.testvalue}"
        if [[ ! -f "$script" ]]; then
            echo "Test file $test_file does not have a matching script."
            read -p "Delete $test_file? (y/n) " delete
            if [[ "$delete" == "y" ]]; then
                rm "$test_file"
                echo "Deleted $test_file"
            fi
        fi
    done

# Validate mode
elif [[ "$MODE" == "validate" ]]; then
    echo "Running in validate mode..."
    pass=0
    fail=0

    for test_file in *.kts.testvalue; do
        script="${test_file%.testvalue}"
        if [[ -f "$script" ]]; then
            input=$(fetch_input "$script")
            output=$(echo "$input" | kotlin "$script" 2>&1)
            if [[ "$output" == "$(cat "$test_file")" ]]; then
                echo "PASS: $script"
                ((pass++))
            else
                echo "FAIL: $script"
                diff -u "$test_file" <(echo "$output")
                ((fail++))
            fi
        else
            echo "Orphaned test file: $test_file (no matching script)"
            ((fail++))
        fi
    done

    echo "Summary: $pass pass, $fail fail"

    if [[ $fail -gt 0 ]]; then
        exit 1
    else
        exit 0
    fi

else
    usage
fi