<?php

namespace TypePhp\Cli;

final class BashCompletion
{
    public static function render(): string
    {
        $options = self::words(CompletionMetadata::options());
        $valueCases = '';
        foreach (CompletionMetadata::values() as $option => $values) {
            if (str_ends_with($option, '=')) {
                continue;
            }
            $valueCases .= '        ' . self::bashPattern($option) . ")\n"
                . '            COMPREPLY=( $(compgen -W '
                . self::quote(self::words($values)) . ' -- "$current") )' . "\n"
                . "            return\n            ;;\n";
        }
        $quotedOptions = self::quote($options);

        $directoryOptions = implode('|', array_map(self::bashPattern(...), CompletionMetadata::directoryOptions()));
        $pythonFileOptions = implode('|', array_map(self::bashPattern(...), CompletionMetadata::pythonFileOptions()));
        $outputFileOptions = implode('|', array_map(self::bashPattern(...), CompletionMetadata::outputFileOptions()));
        $equalsCases = '';
        foreach (CompletionMetadata::values() as $option => $values) {
            if (!str_ends_with($option, '=')) {
                continue;
            }
            $prefix = substr($option, 0, -1);
            $equalsCases .= '        ' . self::bashPattern($prefix) . "=*)\n"
                . '            value="${current#' . $prefix . '=}"' . "\n"
                . '            COMPREPLY=( $(compgen -W ' . self::quote(self::words($values))
                . ' -P ' . self::quote($prefix . '=') . ' -- "$value") )' . "\n"
                . "            return\n            ;;\n";
        }
        foreach (CompletionMetadata::directoryEqualsOptions() as $option) {
            $prefix = substr($option, 0, -1);
            $equalsCases .= '        ' . self::bashPattern($prefix) . "=*)\n"
                . '            value="${current#' . $prefix . '=}"' . "\n"
                . "            compopt -o filenames\n"
                . '            COMPREPLY=()' . "\n"
                . '            while IFS= read -r candidate; do' . "\n"
                . '                COMPREPLY+=("' . $prefix . '=${candidate}")' . "\n"
                . '            done < <(compgen -d -- "$value")' . "\n"
                . "            return\n            ;;\n";
        }

        $script = <<<BASH
# Bash completion for the TypePHP compiler.
# Generated by: tpc --generate-completion=bash

_typephp_tpc_complete_files()
{
    local candidate
    COMPREPLY=()
    while IFS= read -r candidate; do
        if [[ -d "\$candidate" || "\$candidate" == *.php || "\$candidate" == *.yml || "\$candidate" == *.yaml || "\$candidate" == *.prof ]]; then
            COMPREPLY+=("\$candidate")
        fi
    done < <(compgen -f -- "\$1")
}

_typephp_tpc_complete_python_files()
{
    local candidate
    COMPREPLY=()
    while IFS= read -r candidate; do
        if [[ -d "\$candidate" || "\$candidate" == *.py ]]; then
            COMPREPLY+=("\$candidate")
        fi
    done < <(compgen -f -- "\$1")
}

_typephp_tpc_complete_paths()
{
    local mode="\$1" candidate
    COMPREPLY=()
    shift
    while IFS= read -r candidate; do
        COMPREPLY+=("\$candidate")
    done < <(compgen "\$mode" -- "\$1")
}

_typephp_tpc()
{
    local current previous value candidate
    current="\${COMP_WORDS[COMP_CWORD]}"
    previous=""
    if (( COMP_CWORD > 0 )); then
        previous="\${COMP_WORDS[COMP_CWORD - 1]}"
    fi

    local index
    for ((index = 1; index < COMP_CWORD; index++)); do
        if [[ "\${COMP_WORDS[index]}" == -- ]]; then
            compopt -o default
            return
        fi
    done

    case "\$previous" in
{$valueCases}        {$directoryOptions})
            compopt -o filenames
            _typephp_tpc_complete_paths -d "\$current"
            return
            ;;
        {$pythonFileOptions})
            compopt -o filenames
            _typephp_tpc_complete_python_files "\$current"
            return
            ;;
        {$outputFileOptions})
            compopt -o filenames
            _typephp_tpc_complete_paths -f "\$current"
            return
            ;;
    esac

    case "\$current" in
        -O[0-3])
            COMPREPLY=("\$current")
            return
            ;;
        -O*)
            value="\${current#-O}"
            COMPREPLY=( $(compgen -W '0 1 2 3' -P '-O' -- "\$value") )
            return
            ;;
{$equalsCases}        -* )
            COMPREPLY=( $(compgen -W {$quotedOptions} -- "\$current") )
            return
            ;;
    esac

    compopt -o filenames
    _typephp_tpc_complete_files "\$current"
}

complete -F _typephp_tpc tpc
complete -F _typephp_tpc ./tpc
complete -F _typephp_tpc tpc.php
complete -F _typephp_tpc bin/tpc.php
complete -F _typephp_tpc ./bin/tpc.php
BASH;
        return $script . PHP_EOL;
    }

    /** @param list<string> $words */
    private static function words(array $words): string
    {
        return implode(' ', $words);
    }

    private static function quote(string $value): string
    {
        return "'" . str_replace("'", "'\\''", $value) . "'";
    }

    private static function bashPattern(string $value): string
    {
        return str_replace(['\\', '*', '?', '[', ']'], ['\\\\', '\\*', '\\?', '\\[', '\\]'], $value);
    }
}