// Copyright © 2022 Roberto Hidalgo <chinampa@un.rob.mx>
// SPDX-License-Identifier: Apache-2.0
package registry

import (
	"fmt"
	"os"
	"sort"
	"strings"

	"git.rob.mx/nidito/chinampa/internal/commands"
	"git.rob.mx/nidito/chinampa/pkg/command"
	"git.rob.mx/nidito/chinampa/pkg/errors"
	"git.rob.mx/nidito/chinampa/pkg/logger"
	"git.rob.mx/nidito/chinampa/pkg/runtime"
	"github.com/fatih/color"
	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
)

// ContextKeyRuntimeIndex is the string key used to store context in a cobra Command.
const ContextKeyRuntimeIndex = "x-chinampa-runtime-index" // nolint:gosec

var ErrorHandler = errors.HandleCobraExit

var log = logger.Sub("registry")

var registry = &CommandRegistry{
	kv: map[string]*command.Command{},
}

type ByPath []*command.Command

func (cmds ByPath) Len() int           { return len(cmds) }
func (cmds ByPath) Swap(i, j int)      { cmds[i], cmds[j] = cmds[j], cmds[i] }
func (cmds ByPath) Less(i, j int) bool { return cmds[i].FullName() < cmds[j].FullName() }

type CommandRegistry struct {
	kv     map[string]*command.Command
	byPath []*command.Command
}

func Register(cmd *command.Command) {
	log.Tracef("adding to registry: %s", cmd.FullName())
	registry.kv[cmd.FullName()] = cmd
}

func Get(id string) *command.Command {
	return registry.kv[id]
}

func CommandList() []*command.Command {
	if len(registry.byPath) == 0 {
		list := []*command.Command{}
		for _, v := range registry.kv {
			list = append(list, v)
		}
		sort.Sort(ByPath(list))
		registry.byPath = list
	}

	return registry.byPath
}

func subOptions(m command.Options) command.Options {
	m2 := make(map[string]*command.Option, len(m))
	for id, opt := range m {
		m2[id] = opt
	}
	return m2
}

func Execute(version string) error {
	log.Debug("starting execution")
	cmdRoot := command.Root
	ccRoot := newCobraRoot(command.Root)
	ccRoot.CompletionOptions.HiddenDefaultCmd = true
	globalOptions := command.Options{}
	cmdRoot.FlagSet().VisitAll(func(f *pflag.Flag) {
		opt := command.Root.Options[f.Name]
		if f.Name == "version" {
			ccRoot.Flags().AddFlag(f)
		} else {
			ccRoot.PersistentFlags().AddFlag(f)
			globalOptions[f.Name] = opt
		}

		if err := ccRoot.RegisterFlagCompletionFunc(f.Name, opt.CompletionFunction); err != nil {
			log.Errorf("Failed setting up autocompletion for option <%s> of command <%s>", f.Name, cmdRoot.FullName())
		}
	})

	if version != "" {
		name := commands.VersionCommandName
		ccRoot.Annotations["version"] = version
		commands.Version.Hidden = strings.HasPrefix(name, "_")
		commands.Version.Use = name
		ccRoot.AddCommand(commands.Version)
	}
	ccRoot.AddCommand(commands.GenerateCompletions)

	ccRoot.SetHelpFunc(cmdRoot.HelpRenderer(globalOptions))
	for _, cmd := range CommandList() {
		cmd := cmd
		container := ccRoot
		for idx, cp := range cmd.Path {
			if idx == len(cmd.Path)-1 {
				if cmd.Action != nil && cmd.Cobra == nil {
					// nil actions come when the current command consists only
					// of metadata for a "group parent" command
					// and we don't wanna cobraize it like a regular, actionable one
					leaf := ToCobra(cmd, globalOptions, container)
					log.Tracef("cobra: %s => %s", leaf.Name(), container.CommandPath())
					break
				}
				log.Tracef("Found command with no action: %s, assuming group parent action", cmd.Path)
			}

			query := []string{cp}
			found := false
			if len(query) == 1 && query[0] == "help" {
				container = commands.Help
				continue
			}

			for _, sub := range container.Commands() {
				if sub.Name() == cp {
					if parent := FromCobra(container); parent != nil {
						log.Tracef("pflags to %s from %s", sub.Name(), parent.FullName())
						fs := parent.FlagSet()
						sub.PersistentFlags().AddFlagSet(fs)
					}
					container = sub
					found = true
				}
			}

			if !found {
				groupName := strings.Join(query, " ")
				cleanPath := append(cmd.Path[0:idx], query...)  // nolint:gocritic
				groupPath := append(cmdRoot.Path, cleanPath...) // nolint:gocritic

				cmdGlobalOptions := globalOptions

				groupParent := Get(groupName)
				if groupParent == nil {
					log.Tracef("creating group parent for %s", groupPath)
					groupParent = &command.Command{
						Path:        cleanPath,
						Summary:     fmt.Sprintf("%s subcommands", groupName),
						Description: fmt.Sprintf("Runs subcommands within %s", groupName),
						Arguments:   command.Arguments{},
						Options:     command.Options{},
					}
					if groupParent.FullName() == cmd.FullName() {
						groupParent.Summary = cmd.Summary
						groupParent.Description = cmd.Description
					}
					Register(groupParent)
				} else {
					log.Tracef("using pre-existing group parent for %s (%s)", groupPath, groupParent.Path)
				}

				cc := &cobra.Command{
					Use:                        cp,
					Short:                      groupParent.Summary,
					DisableAutoGenTag:          true,
					SuggestionsMinimumDistance: 2,
					SilenceUsage:               true,
					SilenceErrors:              true,
					Annotations: map[string]string{
						ContextKeyRuntimeIndex: strings.Join(cleanPath, " "),
					},
					ValidArgs: []string{},
					Args: func(cmd *cobra.Command, args []string) error {
						if err := cobra.OnlyValidArgs(cmd, args); err == nil {
							return nil
						}

						suggestions := []string{}
						bold := color.New(color.Bold)
						for _, l := range cmd.SuggestionsFor(args[len(args)-1]) {
							suggestions = append(suggestions, bold.Sprint(l))
						}
						last := len(args) - 1
						parent := cmd.CommandPath()
						errMessage := fmt.Sprintf("Unknown subcommand %s of known command %s", bold.Sprint(args[last]), bold.Sprint(parent))
						if len(suggestions) > 0 {
							errMessage += ". Perhaps you meant " + strings.Join(suggestions, ", ") + "?"
						}
						return errors.NotFound{Msg: errMessage, Group: []string{}}
					},
					RunE: func(cc *cobra.Command, args []string) error {
						if len(args) == 0 {
							if cc.Name() == "help" {
								return cc.Help()
							}
							return errors.NotFound{Msg: "No subcommand provided", Group: []string{}}
						}

						return errors.NotFound{Msg: fmt.Sprintf("Unknown subcommand %s", args[0]), Group: []string{}}
					},
				}

				if len(groupParent.Options) > 0 {
					fs := cmd.FlagSet()
					cc.PersistentFlags().AddFlagSet(fs)
					log.Debugf("adding sub-global option set to %s", groupName)
				}

				if container != cc.Root() {
					cmdGlobalOptions = subOptions(globalOptions)
					if p := FromCobra(container); p != nil {
						for key, opt := range p.Options {
							cmdGlobalOptions[key] = opt
						}
					}
				}
				cc.PersistentFlags().AddFlagSet(container.PersistentFlags())

				cc.SetHelpFunc(groupParent.HelpRenderer(cmdGlobalOptions))
				cc.SetHelpCommand(commands.Help)
				container.AddCommand(cc)
				container = cc
			}
		}

		cmd.Path = append(cmdRoot.Path, cmd.Path...)
	}
	cmdRoot.SetCobra(ccRoot)
	commands.Help.Long = strings.ReplaceAll(commands.Help.Long, "@chinampa@", runtime.Executable)
	ccRoot.SetHelpCommand(commands.Help)

	current, remaining, err := ccRoot.Find(os.Args[1:])
	if err != nil {
		current = ccRoot
	}
	log.Debugf("exec: found command %s with args: %s", current.CommandPath(), remaining)

	if sub, _, err := current.Find(remaining); err == nil && sub != current {
		log.Debugf("exec: found sub-command %s", sub.CommandPath())
		current = sub
	}
	log.Debugf("exec: calling %s", current.CommandPath())

	return ErrorHandler(current, current.Execute())
}