package tui

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"agentu/internal/tools"
)

const workflowCommandTimeout = 2 * time.Minute

func (m model) handleStatusCommand(args []string) (string, error) {
	if len(args) != 0 {
		return "", fmt.Errorf("usage: /status")
	}
	out, err := m.runGitCommand("status", "--short")
	if err != nil {
		return out, err
	}
	if strings.TrimSpace(out) == "" {
		return "Working tree clean.", nil
	}
	return "Changed files:\n" + out, nil
}

func (m model) handleDiffCommand(args []string) (string, error) {
	if len(args) > 0 && args[0] == "--stat" {
		out, err := m.runGitCommand(append([]string{"diff", "--stat", "--"}, args[1:]...)...)
		if err != nil {
			return out, err
		}
		if strings.TrimSpace(out) == "" {
			return "No unstaged diff.", nil
		}
		return out, nil
	}
	out, err := m.runGitCommand(append([]string{"diff", "--"}, args...)...)
	if err != nil {
		return out, err
	}
	if strings.TrimSpace(out) == "" {
		return "No unstaged diff.", nil
	}
	return out, nil
}

func (m model) handleTestCommand(args []string) (string, error) {
	command := strings.TrimSpace(strings.Join(args, " "))
	if command == "" {
		var err error
		command, err = defaultTestCommand(m.workflowDir())
		if err != nil {
			return "", err
		}
	}
	out, err := m.runShellCommand(command)
	if err != nil {
		if strings.TrimSpace(out) != "" {
			return out, err
		}
		return "", err
	}
	if strings.TrimSpace(out) == "" {
		return fmt.Sprintf("$ %s\n(no output)", command), nil
	}
	return out, nil
}

func (m model) runGitCommand(args ...string) (string, error) {
	ctx, cancel := context.WithTimeout(m.ctx, workflowCommandTimeout)
	defer cancel()

	cmd := exec.CommandContext(ctx, "git", append([]string{"-C", m.workflowDir()}, args...)...)
	output, err := cmd.CombinedOutput()
	text := tools.FormatResult(string(output))
	if errors.Is(ctx.Err(), context.DeadlineExceeded) {
		return text, fmt.Errorf("git command timed out: %w", ctx.Err())
	}
	if err != nil {
		if strings.TrimSpace(text) != "" {
			return text, fmt.Errorf("git command failed: %w", err)
		}
		return "", fmt.Errorf("git command failed: %w", err)
	}
	return text, nil
}

func (m model) runShellCommand(command string) (string, error) {
	ctx, cancel := context.WithTimeout(m.ctx, workflowCommandTimeout)
	defer cancel()

	shell := os.Getenv("SHELL")
	if shell == "" {
		shell = "/bin/sh"
	}
	cmd := exec.CommandContext(ctx, shell, "-lc", command)
	cmd.Dir = m.workflowDir()

	var combined bytes.Buffer
	cmd.Stdout = &combined
	cmd.Stderr = &combined
	err := cmd.Run()
	text := strings.TrimRight(tools.FormatResult(combined.String()), "\n")
	if text != "" {
		text = fmt.Sprintf("$ %s\n%s", command, text)
	}
	if errors.Is(ctx.Err(), context.DeadlineExceeded) {
		return text, fmt.Errorf("command timed out: %w", ctx.Err())
	}
	if err != nil {
		return text, fmt.Errorf("command failed: %w", err)
	}
	return text, nil
}

func (m model) workflowDir() string {
	if strings.TrimSpace(m.workingDir) == "" {
		return "."
	}
	return m.workingDir
}

func defaultTestCommand(dir string) (string, error) {
	if fileExists(filepath.Join(dir, "go.mod")) {
		return "go test ./...", nil
	}
	if fileExists(filepath.Join(dir, "package.json")) {
		return "npm test", nil
	}
	return "", fmt.Errorf("no default test command found; use /test <command>")
}

func fileExists(path string) bool {
	info, err := os.Stat(path)
	return err == nil && !info.IsDir()
}