package cmd

import (
	"context"
	"fmt"
	"io"
	"log/slog"
	"os"
	"strings"

	tea "github.com/charmbracelet/bubbletea/v2"
	"github.com/charmbracelet/crush/internal/app"
	"github.com/charmbracelet/crush/internal/config"
	"github.com/charmbracelet/crush/internal/db"
	"github.com/charmbracelet/crush/internal/tui"
	"github.com/charmbracelet/crush/internal/version"
	"github.com/charmbracelet/fang"
	"github.com/charmbracelet/x/term"
	"github.com/spf13/cobra"
)

func init() {
	rootCmd.PersistentFlags().StringP("cwd", "c", "", "Current working directory")
	rootCmd.PersistentFlags().BoolP("debug", "d", false, "Debug")

	rootCmd.Flags().BoolP("help", "h", false, "Help")
	rootCmd.Flags().BoolP("yolo", "y", false, "Automatically accept all permissions (dangerous mode)")

	runCmd.Flags().BoolP("quiet", "q", false, "Hide spinner")
	rootCmd.AddCommand(runCmd)
}

var rootCmd = &cobra.Command{
	Use:   "crush",
	Short: "Terminal-based AI assistant for software development",
	Long: `Crush is a powerful terminal-based AI assistant that helps with software development tasks.
It provides an interactive chat interface with AI capabilities, code analysis, and LSP integration
to assist developers in writing, debugging, and understanding code directly from the terminal.`,
	Example: `
# Run in interactive mode
crush

# Run with debug logging
crush -d

# Run with debug logging in a specific directory
crush -d -c /path/to/project

# Print version
crush -v

# Run a single non-interactive prompt
crush run "Explain the use of context in Go"

# Run in dangerous mode (auto-accept all permissions)
crush -y
  `,
	RunE: func(cmd *cobra.Command, args []string) error {
		app, err := setupApp(cmd)
		if err != nil {
			return err
		}
		defer app.Shutdown()

		// Set up the TUI.
		program := tea.NewProgram(
			tui.New(app),
			tea.WithAltScreen(),
			tea.WithContext(cmd.Context()),
			tea.WithMouseCellMotion(),            // Use cell motion instead of all motion to reduce event flooding
			tea.WithFilter(tui.MouseEventFilter), // Filter mouse events based on focus state
		)

		go app.Subscribe(program)

		if _, err := program.Run(); err != nil {
			slog.Error("TUI run error", "error", err)
			return fmt.Errorf("TUI error: %v", err)
		}
		return nil
	},
}

var runCmd = &cobra.Command{
	Use:   "run [prompt...]",
	Short: "Run a single non-interactive prompt",
	Long: `Run a single prompt in non-interactive mode and exit.
The prompt can be provided as arguments or piped from stdin.`,
	Example: `
# Run a simple prompt
crush run Explain the use of context in Go

# Pipe input from stdin
echo "What is this code doing?" | crush run

# Run with quiet mode (no spinner)
crush run -q "Generate a README for this project"
  `,
	RunE: func(cmd *cobra.Command, args []string) error {
		quiet, _ := cmd.Flags().GetBool("quiet")

		app, err := setupApp(cmd)
		if err != nil {
			return err
		}
		defer app.Shutdown()

		prompt := strings.Join(args, " ")

		prompt, err = maybePrependStdin(prompt)
		if err != nil {
			slog.Error("Failed to read from stdin", "error", err)
			return err
		}

		if prompt == "" {
			return fmt.Errorf("no prompt provided")
		}

		// Run non-interactive flow using the App method
		return app.RunNonInteractive(cmd.Context(), prompt, quiet)
	},
}

func Execute() {
	if err := fang.Execute(
		context.Background(),
		rootCmd,
		fang.WithVersion(version.Version),
		fang.WithNotifySignal(os.Interrupt),
	); err != nil {
		os.Exit(1)
	}
}

// setupApp handles the common setup logic for both interactive and non-interactive modes.
// It returns the app instance, config, cleanup function, and any error.
func setupApp(cmd *cobra.Command) (*app.App, error) {
	debug, _ := cmd.Flags().GetBool("debug")
	yolo, _ := cmd.Flags().GetBool("yolo")
	ctx := cmd.Context()

	cwd, err := resolveCwd(cmd)
	if err != nil {
		return nil, err
	}

	cfg, err := config.Init(cwd, debug)
	if err != nil {
		return nil, err
	}

	if cfg.Permissions == nil {
		cfg.Permissions = &config.Permissions{}
	}
	cfg.Permissions.SkipRequests = yolo

	// Connect to DB; this will also run migrations.
	conn, err := db.Connect(ctx, cfg.Options.DataDirectory)
	if err != nil {
		return nil, err
	}

	appInstance, err := app.New(ctx, conn, cfg)
	if err != nil {
		slog.Error("Failed to create app instance", "error", err)
		return nil, err
	}

	return appInstance, nil
}

func maybePrependStdin(prompt string) (string, error) {
	if term.IsTerminal(os.Stdin.Fd()) {
		return prompt, nil
	}
	fi, err := os.Stdin.Stat()
	if err != nil {
		return prompt, err
	}
	if fi.Mode()&os.ModeNamedPipe == 0 {
		return prompt, nil
	}
	bts, err := io.ReadAll(os.Stdin)
	if err != nil {
		return prompt, err
	}
	return string(bts) + "\n\n" + prompt, nil
}

func resolveCwd(cmd *cobra.Command) (string, error) {
	cwd, _ := cmd.Flags().GetString("cwd")
	if cwd != "" {
		err := os.Chdir(cwd)
		if err != nil {
			return "", fmt.Errorf("failed to change directory: %v", err)
		}
		return cwd, nil
	}
	cwd, err := os.Getwd()
	if err != nil {
		return "", fmt.Errorf("failed to get current working directory: %v", err)
	}
	return cwd, nil
}