package cmd

import (
	"io"
	"text/template"

	"go.fifitido.net/cmd/opt"
)

func WriteBashCompletions(out io.Writer, rootCmd *Command) error {
	return bashTpl.Execute(out, map[string]any{
		"RootCmd":    rootCmd,
		"GlobalOpts": opt.Globals(),
	})
}

// TODO: Add --option|--other-option...) to return nothing for options that require a value
// TODO: Add descriptions to completions using https://stackoverflow.com/a/10130007
var bashTpl = template.Must(template.New("bash").Funcs(tplFuncs).Parse(`
{{- $rootCmd := .RootCmd -}}
{{- $progName := $rootCmd.Name -}}
{{- $varName := under $rootCmd.Name -}}

{{- define "cmd" }}
{{ $currIdx := .Index -}}
{{- $nextIdx := inc .Index -}}
{{- $indentSize := mult $currIdx 2 -}}
{{ indent $indentSize }}"{{ .Cmd.Name }}")
{{ indent $indentSize }}  case ${COMP_WORDS[{{ $currIdx }}]} in
{{ indent $indentSize }}	{{ range .Cmd.Subcommands -}}
{{ indent $indentSize }}	{{ template "cmd" (map "Cmd" . "Index" $nextIdx) -}}
{{ indent $indentSize }}	{{ end }}
{{ indent $indentSize }}    *)
{{ indent $indentSize }}      COMPREPLY=($(compgen -W "{{ join .Cmd.Subcommands.Names " " }} {{ join .Cmd.Opts.Names " "  }}" -- $curr))
{{ indent $indentSize }}    ;;
{{ indent $indentSize }}  esac
{{ indent $indentSize }};; # {{ .Cmd.Name }}
{{- end -}}

_{{$varName}}_completions()
{
  COMPREPLY=()

  case ${COMP_WORDS[1]} in
    {{- range .RootCmd.Subcommands -}}
    {{ template "cmd" (map "Cmd" . "Index" 2) -}}
    {{ end }}
    *)
      COMPREPLY=($(compgen -W "{{ join .RootCmd.Subcommands.Names " " }} {{ join .RootCmd.Opts.Names " "  }}" -- $curr))
    ;;
  esac

  # Global Options
  COMPREPLY+=($(compgen -W "{{ join .GlobalOpts.Names " " }}" -- $curr))
}

complete -F _{{$varName}}_completions {{$progName}}
`))