package config

import (
	"errors"
	"fmt"
	"io/fs"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/BurntSushi/toml"
)

const DefaultWebhookPort = 17421

type Settings struct {
	WebhookPort              int    `toml:"webhook_port"`
	BrainstormPrompt         string `toml:"brainstorm_prompt"`
	BrainstormContinuePrompt string `toml:"brainstorm_continue_prompt"`
	ImplementPlanPrompt      string `toml:"implement_plan_prompt"`
	ReviewPrompt             string `toml:"review_prompt"`
	AutoReview               bool   `toml:"auto_review"`
	DevBranch                string `toml:"dev_branch"`
	AutoBuildBranch          string `toml:"auto_build_branch"`
	WorktreePostCreateScript string `toml:"worktree_post_create_script"`
	WorktreePreRemoveScript  string `toml:"worktree_pre_remove_script"`
	ImplTabPreCreateScript   string `toml:"impl_tab_pre_create_script"`
	ImplTabPostCloseScript   string `toml:"impl_tab_post_close_script"`
	ProfilesDir              string `toml:"profiles_dir"`
	SystemPromptCommand      string `toml:"system_prompt_command"`
}

func DefaultSettings() *Settings {
	return &Settings{
		WebhookPort: DefaultWebhookPort,
		AutoReview:  true,
		DevBranch:   "main",
	}
}

// configFilePath returns the path to the config file. It's a variable so tests can override it.
var configFilePath = func() (string, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("resolve home dir: %w", err)
	}
	return filepath.Join(home, ".config", "superwork", "config.toml"), nil
}

func Load() (*Settings, error) {
	return LoadFrom("")
}

func LoadFrom(path string) (*Settings, error) {
	if path == "" {
		var err error
		path, err = configFilePath()
		if err != nil {
			return nil, err
		}
	}
	s := DefaultSettings()
	_, err := toml.DecodeFile(path, s)
	if errors.Is(err, fs.ErrNotExist) {
		return s, nil
	}
	if err != nil {
		return nil, fmt.Errorf("decode config %s: %w", path, err)
	}
	return s, nil
}

func Save(s *Settings) error {
	return SaveTo("", s)
}

func SaveTo(path string, s *Settings) error {
	if path == "" {
		var err error
		path, err = configFilePath()
		if err != nil {
			return err
		}
	}
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return fmt.Errorf("create config dir: %w", err)
	}
	f, err := os.Create(path)
	if err != nil {
		return fmt.Errorf("create config file: %w", err)
	}
	defer f.Close()
	if err := toml.NewEncoder(f).Encode(s); err != nil {
		return fmt.Errorf("encode config: %w", err)
	}
	return nil
}

func WorkspaceRoot() (string, error) {
	out, err := exec.Command("git", "rev-parse", "--show-toplevel").Output()
	if err != nil {
		cwd, cerr := os.Getwd()
		if cerr != nil {
			return "", fmt.Errorf("get cwd: %w", cerr)
		}
		return cwd, nil
	}
	return strings.TrimSpace(string(out)), nil
}

func SpxDir(workspaceRoot string) string {
	return filepath.Join(workspaceRoot, ".spx")
}