package cmd

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"reflect"
	"strings"

	"github.com/BurntSushi/toml"
	"github.com/spf13/cobra"
)

var configCmd = &cobra.Command{
	Use:   "config",
	Short: "View and modify configuration",
}

var configListCmd = &cobra.Command{
	Use:          "list",
	Aliases:      []string{"ls"},
	Short:        "List all configuration values",
	Args:         cobra.NoArgs,
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		defaults := defaultConfig()
		fields := configFields(&config, &defaults)
		for _, f := range fields {
			fmt.Printf("%s = %v\n", f.Key, f.Value)
		}
		return nil
	},
}

var configGetCmd = &cobra.Command{
	Use:          "get <key>",
	Short:        "Print a configuration value",
	Args:         cobra.ExactArgs(1),
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		defaults := defaultConfig()
		fields := configFields(&config, &defaults)
		f := findConfigField(fields, args[0])
		if f == nil {
			err := fmt.Errorf("unknown config key '%s'", args[0])
			if suggestions := suggestConfigKey(fields, args[0]); len(suggestions) > 0 {
				return withHint(err, fmt.Sprintf("did you mean '%s'?", strings.Join(suggestions, "', '")))
			}
			return err
		}
		fmt.Printf("%v\n", f.Value)
		return nil
	},
}

var configPathCmd = &cobra.Command{
	Use:          "path",
	Short:        "Print config file path",
	Args:         cobra.NoArgs,
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		p, err := configPath()
		if err != nil {
			return fmt.Errorf("cannot determine config path: %w", err)
		}
		fmt.Println(p)
		return nil
	},
}

var configEditCmd = &cobra.Command{
	Use:          "edit",
	Short:        "Open config file in $EDITOR",
	Args:         cobra.NoArgs,
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		editor := os.Getenv("EDITOR")
		if editor == "" {
			return withHint(
				fmt.Errorf("EDITOR not set"),
				"set $EDITOR to your preferred text editor",
			)
		}
		p, err := configPath()
		if err != nil {
			return fmt.Errorf("cannot determine config path: %w", err)
		}
		// Create default config if file doesn't exist
		if _, err := os.Stat(p); os.IsNotExist(err) {
			if err := writeConfigFile(defaultConfig()); err != nil {
				return err
			}
		}
		c := exec.Command(editor, p)
		c.Stdin = os.Stdin
		c.Stdout = os.Stdout
		c.Stderr = os.Stderr
		if err := c.Run(); err != nil {
			return err
		}

		cfg, undecoded, migrations, err := loadConfig()
		for _, m := range migrations {
			if m.Conflict {
				warnf("both '%s' and '%s' present; using '%s'", m.Old, m.New, m.New)
			} else {
				warnf("config key '%s' is deprecated, use '%s'", m.Old, m.New)
			}
		}
		if err != nil {
			warnf("config has errors: %v", err)
			printHint("re-run 'pda config edit' to fix")
			return nil
		}
		if len(undecoded) > 0 {
			warnf("unrecognised key(s) will be ignored: %s", strings.Join(undecoded, ", "))
		}
		config = cfg
		configUndecodedKeys = undecoded
		configErr = nil
		okf("saved config: %s", p)
		return nil
	},
}

func writeConfigFile(cfg Config) error {
	p, err := configPath()
	if err != nil {
		return fmt.Errorf("cannot determine config path: %w", err)
	}
	if err := os.MkdirAll(filepath.Dir(p), 0o750); err != nil {
		return fmt.Errorf("cannot create config directory: %w", err)
	}
	f, err := os.Create(p)
	if err != nil {
		return fmt.Errorf("cannot write config: %w", err)
	}
	defer f.Close()
	enc := toml.NewEncoder(f)
	return enc.Encode(cfg)
}

var configInitCmd = &cobra.Command{
	Use:          "init",
	Short:        "Generate default config file",
	Args:         cobra.NoArgs,
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		p, err := configPath()
		if err != nil {
			return fmt.Errorf("cannot determine config path: %w", err)
		}
		newFlag, _ := cmd.Flags().GetBool("new")
		updateFlag, _ := cmd.Flags().GetBool("update")

		if newFlag && updateFlag {
			return fmt.Errorf("--new and --update are mutually exclusive")
		}

		if updateFlag {
			if _, err := os.Stat(p); os.IsNotExist(err) {
				return withHint(
					fmt.Errorf("no config file to update"),
					"use 'pda config init' to create one",
				)
			}
			cfg, _, migrations, loadErr := loadConfig()
			if loadErr != nil {
				return fmt.Errorf("cannot update config: %w", loadErr)
			}
			if err := writeConfigFile(cfg); err != nil {
				return err
			}
			for _, m := range migrations {
				okf("%s migrated to %s", m.Old, m.New)
			}
			okf("updated config: %s", p)
			return nil
		}

		if !newFlag {
			if _, err := os.Stat(p); err == nil {
				return withHint(
					fmt.Errorf("config file already exists"),
					"use '--update' to update your config, or '--new' to get a fresh copy",
				)
			}
		}
		okf("generated config: %s", p)
		return writeConfigFile(defaultConfig())
	},
}

var configSetCmd = &cobra.Command{
	Use:          "set <key> <value>",
	Short:        "Set a configuration value",
	Args:         cobra.ExactArgs(2),
	SilenceUsage: true,
	RunE: func(cmd *cobra.Command, args []string) error {
		key, raw := args[0], args[1]
		cfg := config
		defaults := defaultConfig()
		fields := configFields(&cfg, &defaults)
		f := findConfigField(fields, key)
		if f == nil {
			err := fmt.Errorf("unknown config key '%s'", key)
			if suggestions := suggestConfigKey(fields, key); len(suggestions) > 0 {
				return withHint(err, fmt.Sprintf("did you mean '%s'?", strings.Join(suggestions, "', '")))
			}
			return err
		}

		switch f.Kind {
		case reflect.Bool:
			switch strings.ToLower(raw) {
			case "true":
				f.Field.SetBool(true)
			case "false":
				f.Field.SetBool(false)
			default:
				return fmt.Errorf("cannot set '%s': expected bool (true/false), got '%s'", key, raw)
			}
		case reflect.String:
			f.Field.SetString(raw)
		default:
			return fmt.Errorf("cannot set '%s': unsupported type %s", key, f.Kind)
		}

		if err := validateConfig(cfg); err != nil {
			return fmt.Errorf("cannot set '%s': %w", key, err)
		}

		if err := writeConfigFile(cfg); err != nil {
			return err
		}

		config = cfg
		configUndecodedKeys = nil
		okf("%s set to '%s'", key, raw)
		return nil
	},
}

func init() {
	configInitCmd.Flags().Bool("new", false, "overwrite existing config file")
	configInitCmd.Flags().Bool("update", false, "migrate deprecated keys and fill missing defaults")
	configCmd.AddCommand(configEditCmd)
	configCmd.AddCommand(configGetCmd)
	configCmd.AddCommand(configInitCmd)
	configCmd.AddCommand(configListCmd)
	configCmd.AddCommand(configPathCmd)
	configCmd.AddCommand(configSetCmd)
	rootCmd.AddCommand(configCmd)
}