#!/bin/bash

# AI-Cut: Structured field extraction tool
# Beautiful implementation using composable functions

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/ai-common"

show_usage() {
    cat << 'EOF'
Usage: ai-cut -f FIELDS [FILE...]
Extract structured fields from unstructured text using natural language field descriptions.

Options:
  -f FIELDS   Comma-separated field descriptions (required)
  -j          Output as JSON objects (default: TSV)
  -h          Show this help message
EOF
}

build_extraction_prompt() {
    local fields="$1"
    local json_output="$2"
    
    local format_instructions
    if [[ "$json_output" == "true" ]]; then
        format_instructions='For each line or record in the input, extract the specified fields and output as a JSON object with the field names as keys. Output one JSON object per line. Output ONLY the raw JSON - do not wrap in markdown code blocks or add any other formatting.

Example format:
{"field1": "value1", "field2": "value2", "field3": "value3"}'
    else
        format_instructions='For each line or record in the input, extract the specified fields and output as tab-separated values. Output the fields in the same order as specified.

Example format:
value1	value2	value3'
    fi
    
    cat << EOF
You are a structured data extraction tool. Extract the following fields from the unstructured text: $fields

$format_instructions
EOF
}

process_extraction_response() {
    local response="$1"
    local json_output="$2"
    
    if [[ "$json_output" == "true" ]]; then
        process_json_response "$response"
    else
        echo "$response"
        return 0
    fi
}

validate_and_setup() {
    local fields="$1"
    shift
    local files=("$@")
    
    ensure_dependencies
    ensure_argument_provided "Field specification (-f)" "$fields" show_usage
    
    [[ ${#files[@]} -gt 0 ]] && ensure_files_exist "${files[@]}"
}

main() {
    local fields=""
    local json_output="false"
    local files=()
    
    # Parse options
    while getopts "f:jh" opt; do
        case $opt in
            f) fields="$OPTARG" ;;
            j) json_output="true" ;;
            h) handle_help_option show_usage ;;
            \?) handle_invalid_option "$OPTARG" ;;
        esac
    done
    
    shift $((OPTIND-1))
    files=("$@")
    
    # Early validation with immediate exit on failure
    validate_and_setup "$fields" "${files[@]}"
    
    # Process input with early exit
    local input
    input=$(process_input_sources "${files[@]}") || exit "$EXIT_NO_MATCH"
    
    # Execute LLM request with early exit
    local prompt response
    prompt=$(build_extraction_prompt "$fields" "$json_output")
    response=$(execute_llm_request "$prompt" "$input") || handle_llm_error $?
    
    # Process response with early exit
    local result
    result=$(process_extraction_response "$response" "$json_output") || exit $?
    
    echo "$result"
}

main "$@"