using namespace System.Management.Automation
using namespace System.Management.Automation.Language

Register-ArgumentCompleter -Native -CommandName '{{PROJECT_EXECUTABLE}}' -ScriptBlock {
    param($wordToComplete, $commandAst, $cursorPosition)

    $ArrayStyle      = @('default', 'auto', 'full', 'plain', 'changes', 'header', 'header-filename', 'header-filesize', 'grid', 'rule', 'numbers', 'snip')
    $ArrayCompletion = @('bash', 'fish', 'zsh', 'ps1')
    $ArrayWhen       = @('auto', 'never', 'always')
    $ArrayYesNo      = @('never', 'always')
    $ArrayWrap       = @('always', 'never', 'character')
    $ArrayBinary     = @('no-printing', 'as-text')
    $ArrayPrint      = @('unicode', 'caret')

    function Get-MyThemes(){
        $themes = {{PROJECT_EXECUTABLE}} --list-themes | ForEach-Object {$_  -replace "^(.*)$", '''$1'''} | select-object
        return $themes
    }

    function Get-MyLanguages(){
        $themes = {{PROJECT_EXECUTABLE}} --list-languages | ForEach-Object{[pscustomobject]@{MyParameter=$_.Substring(0,$_.IndexOf(":")).Trim();MyDescription=$_.Substring($_.IndexOf(":")+1)}} | select-object
        return $themes
    }

    $commandElements = $commandAst.CommandElements
    $command = @(
        '{{PROJECT_EXECUTABLE}}'
        for ($i = 1; $i -lt $commandElements.Count; $i++) {
            $element = $commandElements[$i]
            if ($element -isnot [StringConstantExpressionAst] -or
                $element.StringConstantType -ne [StringConstantType]::BareWord -or
                #$element.Value.StartsWith('-') -or
                $element.Value -eq $wordToComplete) {
                break
        }
        $element.Value
    }) -join ';'

    $completions = @(switch -Wildcard ($command) {
        '*;--help' {
            break
        }
        '*;--version' {
            break
        }
        '*;--acknowledgements' {
            break
        }
        '*;--language' {
            Get-MyLanguages |
            ForEach-Object {[CompletionResult]::new(($_.MyParameter -replace "^(.*)$", '''$1'''), $_.MyParameter, [CompletionResultType]::ParameterName, $_.MyDescription ?? '_no value_')}
            break
        }
        '*;--theme' {
            Get-MyThemes |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterName, $_)}
            break
        }
        '*;--binary' {
            $ArrayBinary |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--style' {
            $ArrayStyle |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--wrap' {
            $ArrayWrap |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--color' {
            $ArrayWhen |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--italic-text' {
            $ArrayYesNo |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--paging' {
            $ArrayWhen |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--decorations' {
            $ArrayWhen |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--completion' {
            $ArrayCompletion |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--strip-ansi' {
            $ArrayWhen |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--nonprintable-notation' {
            $ArrayPrint |
            ForEach-Object {[System.Management.Automation.CompletionResult]::new($_, $_, [CompletionResultType]::ParameterValue, $_)}
            break
        }
        '*;--generate-config-file' {
            break
        }
        '{{PROJECT_EXECUTABLE}};cache' {
            [CompletionResult]::new('--source'                , 'source'                , [CompletionResultType]::ParameterName, 'Use a different directory to load syntaxes and themes from.')
            [CompletionResult]::new('--target'                , 'target'                , [CompletionResultType]::ParameterName, 'Use a different directory to store the cached syntax and theme set.')
        #   [CompletionResult]::new('-b'                      , 'b'                     , [CompletionResultType]::ParameterName, 'Initialize (or update) the syntax/theme cache.')
            [CompletionResult]::new('--build'                 , 'build'                 , [CompletionResultType]::ParameterName, 'Initialize (or update) the syntax/theme cache.')
        #   [CompletionResult]::new('-c'                      , 'c'                     , [CompletionResultType]::ParameterName, 'Remove the cached syntax definitions and themes.')
            [CompletionResult]::new('--clear'                 , 'clear'                 , [CompletionResultType]::ParameterName, 'Remove the cached syntax definitions and themes.')
            [CompletionResult]::new('--blank'                 , 'blank'                 , [CompletionResultType]::ParameterName, 'Create completely new syntax and theme sets (instead of appending to the default sets).')
        #   [CompletionResult]::new('-h'                      , 'h'                     , [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help'                  , 'help'                  , [CompletionResultType]::ParameterName, 'Prints help information')
        #   [CompletionResult]::new('-V'                      , 'V'                     , [CompletionResultType]::ParameterName, 'Prints version information')
        #   [CompletionResult]::new('--version'               , 'version'               , [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        default {
        #   [CompletionResult]::new('-l'                      , 'l'                     , [CompletionResultType]::ParameterName, 'Set the language for syntax highlighting.')
            [CompletionResult]::new('--language'              , 'language'              , [CompletionResultType]::ParameterName, 'Set the language for syntax highlighting.')
        #   [CompletionResult]::new('-H'                      , 'H'                     , [CompletionResultType]::ParameterName, 'Highlight lines N through M.')
            [CompletionResult]::new('--highlight-line'        , 'highlight-line'        , [CompletionResultType]::ParameterName, 'Highlight lines N through M.')
            [CompletionResult]::new('--file-name'             , 'file-name'             , [CompletionResultType]::ParameterName, 'Specify the name to display for a file.')
            [CompletionResult]::new('--diff-context'          , 'diff-context'          , [CompletionResultType]::ParameterName, 'diff-context')
            [CompletionResult]::new('--tabs'                  , 'tabs'                  , [CompletionResultType]::ParameterName, 'Set the tab width to T spaces.')
            [CompletionResult]::new('--wrap'                  , 'wrap'                  , [CompletionResultType]::ParameterName, 'Specify the text-wrapping mode (*auto*, character).')
            [CompletionResult]::new('--terminal-width'        , 'terminal-width'        , [CompletionResultType]::ParameterName, 'Explicitly set the width of the terminal instead of determining it automatically. If prefixed with ''+'' or ''-'', the value will be treated as an offset to the actual terminal width. See also: ''--wrap''.')
            [CompletionResult]::new('--color'                 , 'color'                 , [CompletionResultType]::ParameterName, 'When to use colors (*auto*, never, always).')
            [CompletionResult]::new('--italic-text'           , 'italic-text'           , [CompletionResultType]::ParameterName, 'Use italics in output (always, *never*)')
            [CompletionResult]::new('--decorations'           , 'decorations'           , [CompletionResultType]::ParameterName, 'When to show the decorations (*auto*, never, always).')
            [CompletionResult]::new('--paging'                , 'paging'                , [CompletionResultType]::ParameterName, 'Specify when to use the pager, or use ''-P'' to disable (*auto*, never, always).')
            [CompletionResult]::new('--pager'                 , 'pager'                 , [CompletionResultType]::ParameterName, 'Determine which pager to use.')
        #   [CompletionResult]::new('-m'                      , 'm'                     , [CompletionResultType]::ParameterName, 'Use the specified syntax for files matching the glob pattern (''*.cpp:C++'').')
            [CompletionResult]::new('--map-syntax'            , 'map-syntax'            , [CompletionResultType]::ParameterName, 'Use the specified syntax for files matching the glob pattern (''*.cpp:C++'').')
            [CompletionResult]::new('--theme'                 , 'theme'                 , [CompletionResultType]::ParameterName, 'Set the color theme for syntax highlighting.')
            [CompletionResult]::new('--theme-dark'            , 'themedark'             , [CompletionResultType]::ParameterName, 'Set the color theme for syntax highlighting for dark backgrounds.')
            [CompletionResult]::new('--theme-light'           , 'themelight'            , [CompletionResultType]::ParameterName, 'Set the color theme for syntax highlighting for light backgrounds.')
            [CompletionResult]::new('--style'                 , 'style'                 , [CompletionResultType]::ParameterName, 'Comma-separated list of style elements to display (*default*, auto, full, plain, changes, header, header-filename, header-filesize, grid, rule, numbers, snip).')
        #   [CompletionResult]::new('-r'                      , 'r'                     , [CompletionResultType]::ParameterName, 'Only print the lines from N to M.')
            [CompletionResult]::new('--line-range'            , 'line-range'            , [CompletionResultType]::ParameterName, 'Only print the lines from N to M.')
        #   [CompletionResult]::new('-A'                      , 'A'                     , [CompletionResultType]::ParameterName, 'Show non-printable characters (space, tab, newline, ..).')
            [CompletionResult]::new('--show-all'              , 'show-all'              , [CompletionResultType]::ParameterName, 'Show non-printable characters (space, tab, newline, ..).')
            [CompletionResult]::new('--nonprintable-notation' , 'nonprintable-notation' , [CompletionResultType]::ParameterName, 'Set notation for non-printable characters. (unicode, caret)')
            [CompletionResult]::new('--chop-long-lines'       , 'chop-long-lines'       , [CompletionResultType]::ParameterName, 'Truncate all lines longer than screen width. Alias for ''--wrap=never''.')
            [CompletionResult]::new('--binary'                , 'binary'                , [CompletionResultType]::ParameterName, 'How to treat binary content. (*no-printing*, as-text)')
            [CompletionResult]::new('--ignored-suffix'        , 'ignored-suffix'        , [CompletionResultType]::ParameterName, 'Ignore extension. For example: ''bat --ignored-suffix ".dev" my_file.json.dev'' will use JSON syntax, and ignore ''.dev''')
            [CompletionResult]::new('--squeeze-blank'         , 'squeeze-blank'         , [CompletionResultType]::ParameterName, 'Squeeze consecutive empty lines into a single empty line.')
            [CompletionResult]::new('--squeeze-limit'         , 'squeeze-limit'         , [CompletionResultType]::ParameterName, 'Set the maximum number of consecutive empty lines to be printed.')
            [CompletionResult]::new('--strip-ansi'            , 'strip-ansi'            , [CompletionResultType]::ParameterName, 'Specify when to strip ANSI escape sequences from the input. The automatic mode will remove escape sequences unless the syntax highlighting language is plain text. (auto, always, *never*).')
        #   [CompletionResult]::new('-p'                      , 'p'                     , [CompletionResultType]::ParameterName, 'Show plain style (alias for ''--style=plain'').')
            [CompletionResult]::new('--plain'                 , 'plain'                 , [CompletionResultType]::ParameterName, 'Show plain style (alias for ''--style=plain'').')
        #   [CompletionResult]::new('-d'                      , 'd'                     , [CompletionResultType]::ParameterName, 'Only show lines that have been added/removed/modified.')
            [CompletionResult]::new('--diff'                  , 'diff'                  , [CompletionResultType]::ParameterName, 'Only show lines that have been added/removed/modified.')
        #   [CompletionResult]::new('-n'                      , 'n'                     , [CompletionResultType]::ParameterName, 'Show line numbers (alias for ''--style=numbers'').')
            [CompletionResult]::new('--number'                , 'number'                , [CompletionResultType]::ParameterName, 'Show line numbers (alias for ''--style=numbers'').')
        #   [CompletionResult]::new('-f'                      , 'f'                     , [CompletionResultType]::ParameterName, 'f')
            [CompletionResult]::new('--force-colorization'    , 'force-colorization'    , [CompletionResultType]::ParameterName, 'force-colorization')
        #   [CompletionResult]::new('-P'                      , 'P'                     , [CompletionResultType]::ParameterName, 'Alias for ''--paging=never''')
            [CompletionResult]::new('--no-paging'             , 'no-paging'             , [CompletionResultType]::ParameterName, 'Alias for ''--paging=never''')
            [CompletionResult]::new('--list-themes'           , 'list-themes'           , [CompletionResultType]::ParameterName, 'Display all supported highlighting themes.')
        #   [CompletionResult]::new('-L'                      , 'L'                     , [CompletionResultType]::ParameterName, 'Display all supported languages.')
            [CompletionResult]::new('--list-languages'        , 'list-languages'        , [CompletionResultType]::ParameterName, 'Display all supported languages.')
        #   [CompletionResult]::new('-u'                      , 'u'                     , [CompletionResultType]::ParameterName, 'u')
            [CompletionResult]::new('--unbuffered'            , 'unbuffered'            , [CompletionResultType]::ParameterName, 'unbuffered')
            [CompletionResult]::new('--completion'            , 'completion'            , [CompletionResultType]::ParameterName, 'Show shell completion for a certain shell. [possible values: bash, fish, zsh, ps1]')
            [CompletionResult]::new('--no-config'             , 'no-config'             , [CompletionResultType]::ParameterName, 'Do not use the configuration file')
            [CompletionResult]::new('--no-custom-assets'      , 'no-custom-assets'      , [CompletionResultType]::ParameterName, 'Do not load custom assets')
            [CompletionResult]::new('--lessopen'              , 'lessopen'              , [CompletionResultType]::ParameterName, 'Enable the $LESSOPEN preprocessor')
            [CompletionResult]::new('--no-lessopen'           , 'no-lessopen'           , [CompletionResultType]::ParameterName, 'Disable the $LESSOPEN preprocessor if enabled (overrides --lessopen)')
            [CompletionResult]::new('--config-file'           , 'config-file'           , [CompletionResultType]::ParameterName, 'Show path to the configuration file.')
            [CompletionResult]::new('--generate-config-file'  , 'generate-config-file'  , [CompletionResultType]::ParameterName, 'Generates a default configuration file.')
            [CompletionResult]::new('--config-dir'            , 'config-dir'            , [CompletionResultType]::ParameterName, 'Show bat''s configuration directory.')
            [CompletionResult]::new('--cache-dir'             , 'cache-dir'             , [CompletionResultType]::ParameterName, 'Show bat''s cache directory.')
            [CompletionResult]::new('--acknowledgements'      , 'acknowledgements'      , [CompletionResultType]::ParameterName, 'Show acknowledgements.')
            [CompletionResult]::new('--set-terminal-title'    , 'set-terminal-title'    , [CompletionResultType]::ParameterName, 'Sets terminal title to filenames when using a pager.')
            [CompletionResult]::new('--diagnostic'            , 'diagnostic'            , [CompletionResultType]::ParameterName, 'Show diagnostic information for bug reports.')
        #   [CompletionResult]::new('-h'                      , 'h'                     , [CompletionResultType]::ParameterName, 'Print this help message.')
            [CompletionResult]::new('--help'                  , 'help'                  , [CompletionResultType]::ParameterName, 'Print this help message.')
        #   [CompletionResult]::new('-V'                      , 'V'                     , [CompletionResultType]::ParameterName, 'Show version information.')
            [CompletionResult]::new('--version'               , 'version'               , [CompletionResultType]::ParameterName, 'Show version information.')
            break
        }
    })

    $completions.Where{ $_.CompletionText -like "$wordToComplete*" } |
        Sort-Object -Property CompletionText
}