package command

import (
	"fmt"
	"strings"

	"git.gophernest.net/azpect/TextEditor/internal/action"
	tea "github.com/charmbracelet/bubbletea"
)

// Command: Represents a command that can be executed from command mode.
type Command struct {
	Name      string                                                  // Full name: "quit"
	ShortForm string                                                  // Minimum abbreviation: "q"
	Handler   func(m action.Model, args []string, force bool) tea.Cmd // Handler function
}

// Registry: Holds all registered commands.
type Registry struct {
	commands []Command
}

// NewRegistry: Creates a new command registry with default commands.
func NewRegistry() *Registry {
	r := &Registry{}
	r.registerDefaults()
	return r
}

// Registry.Register: Adds a command to the registry.
func (r *Registry) Register(cmd Command) {
	r.commands = append(r.commands, cmd)
}

// Registry.Lookup: Finds a command by name or abbreviation with error handling.
func (r *Registry) Lookup(input string) (*Command, error) {
	if input == "" {
		return nil, fmt.Errorf("no command given")
	}

	var matches []*Command

	for i := range r.commands {
		cmd := &r.commands[i]

		// Exact match on short form
		if input == cmd.ShortForm {
			return cmd, nil
		}

		// Exact match on full name
		if input == cmd.Name {
			return cmd, nil
		}

		// Prefix match: input must be at least as long as short form
		// and must be a prefix of the full name
		if len(input) >= len(cmd.ShortForm) && strings.HasPrefix(cmd.Name, input) {
			matches = append(matches, cmd)
		}
	}

	if len(matches) == 0 {
		return nil, fmt.Errorf("unknown command: %s", input)
	}
	if len(matches) > 1 {
		names := make([]string, len(matches))
		for i, m := range matches {
			names[i] = m.Name
		}
		return nil, fmt.Errorf("ambiguous command: %s (could be: %s)", input, strings.Join(names, ", "))
	}

	return matches[0], nil
}

// Parse: Splits a command line into command name and arguments.
func Parse(cmdLine string) (name string, args []string, force bool) {
	parts := strings.Fields(cmdLine)
	if len(parts) == 0 {
		return "", nil, false
	}

	name = parts[0]
	args = parts[1:]

	// Check if command ends with ! (force flag)
	if strings.HasSuffix(name, "!") {
		name = strings.TrimSuffix(name, "!")
		force = true
	}

	return name, args, force
}

// Registry.Execute: Parses and executes a command line.
func (r *Registry) Execute(m action.Model, cmdLine string) (tea.Cmd, error) {
	name, args, force := Parse(cmdLine)

	cmd, err := r.Lookup(name)
	if err != nil {
		return nil, err
	}

	return cmd.Handler(m, args, force), nil
}

// DefaultRegistry is the global command registry
var DefaultRegistry = NewRegistry()

// Registry.registerDefaults: Registers the built-in commands.
func (r *Registry) registerDefaults() {
	// Quit commands
	r.Register(Command{
		Name:      "quit",
		ShortForm: "q",
		Handler:   cmdQuit,
	})

	r.Register(Command{
		Name:      "qall",
		ShortForm: "qa",
		Handler:   cmdQuitAll,
	})

	// Write commands
	r.Register(Command{
		Name:      "write",
		ShortForm: "w",
		Handler:   cmdWrite,
	})

	r.Register(Command{
		Name:      "wall",
		ShortForm: "wa",
		Handler:   cmdWriteAll,
	})

	r.Register(Command{
		Name:      "wq",
		ShortForm: "wq",
		Handler:   cmdWriteQuit,
	})

	r.Register(Command{
		Name:      "wqall",
		ShortForm: "wqa",
		Handler:   cmdWriteQuitAll,
	})

	// Set command
	r.Register(Command{
		Name:      "set",
		ShortForm: "se",
		Handler:   cmdSet,
	})

	// Register commands
	r.Register(Command{
		Name:      "register",
		ShortForm: "reg",
		Handler:   cmdRegisters,
	})

	// History commands
	r.Register(Command{
		Name:      "history",
		ShortForm: "his",
		Handler:   cmdHistory,
	})

	// Buffer commands
	r.Register(Command{
		Name:      "buffers",
		ShortForm: "buffers",
		Handler:   cmdListBuffers,
	})

	r.Register(Command{
		Name:      "ls",
		ShortForm: "ls",
		Handler:   cmdListBuffers,
	})

	r.Register(Command{
		Name:      "bn",
		ShortForm: "bn",
		Handler:   cmdNextBuffer,
	})

	r.Register(Command{
		Name:      "bp",
		ShortForm: "bp",
		Handler:   cmdPrevBuffer,
	})

	r.Register(Command{
		Name:      "bf",
		ShortForm: "bf",
		Handler:   cmdFirstBuffer,
	})

	r.Register(Command{
		Name:      "bl",
		ShortForm: "bl",
		Handler:   cmdLastBuffer,
	})

	r.Register(Command{
		Name:      "b",
		ShortForm: "b",
		Handler:   cmdSelectBuffer,
	})

	r.Register(Command{
		Name:      "bdelete",
		ShortForm: "bd",
		Handler:   cmdDeleteBuffer,
	})

	// File commands
	r.Register(Command{
		Name:      "edit",
		ShortForm: "e",
		Handler:   cmdEdit,
	})

	// Color scheme commands
	r.Register(Command{
		Name:      "colorscheme",
		ShortForm: "colo",
		Handler:   cmdColorscheme,
	})

	r.Register(Command{
		Name:      "colorschemes",
		ShortForm: "colorschemes",
		Handler:   cmdListColorschemes,
	})
}