// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>

package cli

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"
)

var _ = fmt.Print

type OptionType int

const (
	StringOption OptionType = iota
	IntegerOption
	FloatOption
	BoolOption
	CountOption
)

type Alias struct {
	NameWithoutHyphens string
	IsShort            bool
	IsUnset            bool
}

func (self *Alias) String() string {
	if self.IsShort {
		return "-" + self.NameWithoutHyphens
	}
	return "--" + self.NameWithoutHyphens
}

type Option struct {
	Name       string
	Aliases    []Alias
	Choices    map[string]bool
	Default    string
	OptionType OptionType
	Hidden     bool
	Depth      int
	HelpText   string
	Parent     *Command

	values_from_cmdline        []string
	parsed_values_from_cmdline []interface{}
	seen_option                string
}

func (self *Option) needs_argument() bool {
	return self.OptionType != BoolOption && self.OptionType != CountOption
}

func (self *Option) HasAlias(name_without_hyphens string, is_short bool) bool {
	for _, a := range self.Aliases {
		if a.IsShort == is_short && a.NameWithoutHyphens == name_without_hyphens {
			return true
		}
	}
	return false
}

var mpat *regexp.Regexp

type ParseError struct {
	Option  *Option
	Message string
}

func (self *ParseError) Error() string { return self.Message }

func NormalizeOptionName(name string) string {
	return strings.ReplaceAll(strings.TrimLeft(name, "-"), "_", "-")
}

func (self *Option) add_value(val string) error {
	name_without_hyphens := NormalizeOptionName(self.seen_option)
	switch self.OptionType {
	case BoolOption:
		for _, x := range self.Aliases {
			if x.NameWithoutHyphens == name_without_hyphens {
				if x.IsUnset {
					self.values_from_cmdline = append(self.values_from_cmdline, "false")
					self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, false)
				} else {
					self.values_from_cmdline = append(self.values_from_cmdline, "true")
					self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, true)
				}
				return nil
			}
		}
	case StringOption:
		if self.Choices != nil && !self.Choices[val] {
			c := make([]string, len(self.Choices))
			for k := range self.Choices {
				c = append(c, k)
			}
			return &ParseError{Option: self, Message: fmt.Sprintf(":yellow:`%s` is not a valid value for :bold:`%s`. Valid values: %s",
				val, self.seen_option, strings.Join(c, ", "),
			)}
		}
		self.values_from_cmdline = append(self.values_from_cmdline, val)
		self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, val)
	case IntegerOption:
		pval, err := strconv.ParseInt(val, 0, 0)
		if err != nil {
			return &ParseError{Option: self, Message: fmt.Sprintf(
				":yellow:`%s` is not a valid number for :bold:`%s`. Only integers in decimal, hexadecimal, binary or octal notation are accepted.", val, self.seen_option)}
		}
		self.values_from_cmdline = append(self.values_from_cmdline, val)
		self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, pval)
	case FloatOption:
		pval, err := strconv.ParseFloat(val, 64)
		if err != nil {
			return &ParseError{Option: self, Message: fmt.Sprintf(
				":yellow:`%s` is not a valid number for :bold:`%s`. Only floats in decimal and hexadecimal notation are accepted.", val, self.seen_option)}
		}
		self.values_from_cmdline = append(self.values_from_cmdline, val)
		self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, pval)
	case CountOption:
		self.values_from_cmdline = append(self.values_from_cmdline, val)
		self.parsed_values_from_cmdline = append(self.parsed_values_from_cmdline, 1)
	}
	return nil
}

type CommandGroup struct {
	SubCommands []*Command
	Title       string
}

func (self *CommandGroup) AddSubCommand(parent *Command, name string) (*Command, error) {
	for _, c := range self.SubCommands {
		if c.Name == name {
			return nil, fmt.Errorf("A subcommand with the name %#v already exists in the parent command: %#v", name, parent.Name)
		}
	}
	ans := Command{
		Name:   name,
		Parent: parent,
	}
	return &ans, nil
}

type OptionGroup struct {
	Options []*Option
	Title   string
}

func (self *OptionGroup) AddOption(parent *Command, items ...string) (*Option, error) {
	ans, err := OptionFromString(items...)
	if err == nil {
		ans.Parent = parent
	}
	return ans, err
}

func (self *OptionGroup) FindOption(name_with_hyphens string) *Option {
	is_short := !strings.HasPrefix(name_with_hyphens, "--")
	option_name := NormalizeOptionName(name_with_hyphens)
	for _, q := range self.Options {
		if q.HasAlias(option_name, is_short) {
			return q
		}
	}
	return nil
}

type Command struct {
	Name             string
	Usage, HelpText  string
	Hidden           bool
	SubCommandGroups []*CommandGroup
	OptionGroups     []*OptionGroup
	Parent           *Command

	AllowOptionsAfterArgs int
	SubCommandIsOptional  bool

	args []string
}

func NewRootCommand() *Command {
	ans := Command{
		SubCommandGroups: make([]*CommandGroup, 0, 8),
		OptionGroups:     make([]*OptionGroup, 0, 8),
		args:             make([]string, 0, 8),
	}
	return &ans
}

func (self *Command) AddSubCommandGroup(title string) *CommandGroup {
	for _, g := range self.SubCommandGroups {
		if g.Title == title {
			return g
		}
	}
	ans := CommandGroup{Title: title, SubCommands: make([]*Command, 0, 8)}
	self.SubCommandGroups = append(self.SubCommandGroups, &ans)
	return &ans
}

func (self *Command) AddSubCommand(group string, name string) (*Command, error) {
	return self.AddSubCommandGroup(group).AddSubCommand(self, name)
}

func (self *Command) HasSubCommands() bool {
	for _, g := range self.SubCommandGroups {
		if len(g.SubCommands) > 0 {
			return true
		}
	}
	return false
}

func (self *Command) FindSubCommand(name string) *Command {
	for _, g := range self.SubCommandGroups {
		for _, c := range g.SubCommands {
			if c.Name == name {
				return c
			}
		}
	}
	return nil
}

func (self *Command) AddOptionGroup(title string) *OptionGroup {
	for _, g := range self.OptionGroups {
		if g.Title == title {
			return g
		}
	}
	ans := OptionGroup{Title: title, Options: make([]*Option, 0, 8)}
	self.OptionGroups = append(self.OptionGroups, &ans)
	return &ans
}

func (self *Command) AddOption(items ...string) (*Option, error) {
	return self.AddOptionGroup("").AddOption(self, items...)
}

func (self *Command) AddOptionToGroup(group string, items ...string) (*Option, error) {
	return self.AddOptionGroup(group).AddOption(self, items...)
}

func (self *Command) FindOption(name_with_hyphens string) *Option {
	for _, g := range self.OptionGroups {
		q := g.FindOption(name_with_hyphens)
		if q != nil {
			return q
		}
	}
	depth := 0
	for p := self.Parent; p != nil; p = p.Parent {
		depth++
		q := p.FindOption(name_with_hyphens)
		if q != nil && q.Depth >= depth {
			return q
		}
	}
	return nil
}

type Context struct {
	SeenCommands []*Command
}