package main

import (
	"archive/zip"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	tea "github.com/charmbracelet/bubbletea"
)

func executeAction(versionDir string, action Action, index int, backupDir string) tea.Cmd {
	total := index + 1
	prefix := fmt.Sprintf("[%d]", total)

	switch action.Type {
	case "add":
		return executeAdd(versionDir, action, index, backupDir, prefix)
	case "delete":
		return func() tea.Msg {
			absPath := filepath.Join(versionDir, action.Path)
			if err := backupPath(versionDir, action.Path, backupDir); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("backup failed: %w", err)}
			}
			if err := os.RemoveAll(absPath); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("delete failed: %w", err)}
			}
			return actionCompleteMsg{index: index}
		}
	case "copy":
		return func() tea.Msg {
			dst := filepath.Join(versionDir, action.NewPath)
			if _, err := os.Stat(dst); err == nil {
				if err := backupPath(versionDir, action.NewPath, backupDir); err != nil {
					return actionErrorMsg{index: index, err: fmt.Errorf("backup failed: %w", err)}
				}
			}
			src := filepath.Join(versionDir, action.Path)
			if err := copyPath(src, dst); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("copy failed: %w", err)}
			}
			return actionCompleteMsg{index: index}
		}
	case "move":
		return func() tea.Msg {
			src := filepath.Join(versionDir, action.Path)
			dst := filepath.Join(versionDir, action.NewPath)
			if _, err := os.Stat(dst); err == nil {
				if err := backupPath(versionDir, action.NewPath, backupDir); err != nil {
					return actionErrorMsg{index: index, err: fmt.Errorf("backup failed: %w", err)}
				}
			}
			if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("mkdir failed: %w", err)}
			}
			if err := os.Rename(src, dst); err != nil {
				if err := copyPath(src, dst); err != nil {
					return actionErrorMsg{index: index, err: fmt.Errorf("move failed: %w", err)}
				}
				os.RemoveAll(src)
			}
			return actionCompleteMsg{index: index}
		}
	default:
		return func() tea.Msg {
			return actionErrorMsg{index: index, err: fmt.Errorf("unknown action type: %s", action.Type)}
		}
	}
}

func executeAdd(versionDir string, action Action, index int, backupDir, prefix string) tea.Cmd {
	return func() tea.Msg {
		absPath := filepath.Join(versionDir, action.Path)

		if err := os.MkdirAll(filepath.Dir(absPath), 0o755); err != nil {
			return actionErrorMsg{index: index, err: fmt.Errorf("mkdir failed: %w", err)}
		}

		if _, err := os.Stat(absPath); err == nil {
			if err := backupPath(versionDir, action.Path, backupDir); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("backup failed: %w", err)}
			}
		}

		err := downloadFile(action.URL, absPath)
		if err != nil {
			if len(action.Mirrors) > 0 {
				return mirrorChoiceMsg{index: index, mirrors: action.Mirrors, action: action}
			}
			return actionErrorMsg{index: index, err: fmt.Errorf("download failed: %w", err)}
		}

		if action.Unzip {
			destDir := filepath.Dir(absPath)
			if err := unzipFile(absPath, destDir); err != nil {
				return actionErrorMsg{index: index, err: fmt.Errorf("unzip failed: %w", err)}
			}
			os.Remove(absPath)
		}

		return actionCompleteMsg{index: index}
	}
}

func waitForProgress(ch chan float64, index int) tea.Cmd {
	return func() tea.Msg {
		p, ok := <-ch
		if !ok {
			return nil
		}
		return actionProgressMsg{percent: p}
	}
}

func downloadFile(url, destPath string) error {
	resp, err := http.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("HTTP %d", resp.StatusCode)
	}

	tmpPath := destPath + ".tmp"
	f, err := os.Create(tmpPath)
	if err != nil {
		return err
	}

	_, err = io.Copy(f, resp.Body)
	f.Close()
	if err != nil {
		os.Remove(tmpPath)
		return err
	}

	return os.Rename(tmpPath, destPath)
}

func unzipFile(zipPath, destDir string) error {
	r, err := zip.OpenReader(zipPath)
	if err != nil {
		return err
	}
	defer r.Close()

	for _, f := range r.File {
		target := filepath.Join(destDir, f.Name)

		if !strings.HasPrefix(filepath.Clean(target), filepath.Clean(destDir)+string(os.PathSeparator)) {
			continue
		}

		if f.FileInfo().IsDir() {
			os.MkdirAll(target, 0o755)
			continue
		}

		if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
			return err
		}

		rc, err := f.Open()
		if err != nil {
			return err
		}

		outFile, err := os.Create(target)
		if err != nil {
			rc.Close()
			return err
		}

		_, err = io.Copy(outFile, rc)
		outFile.Close()
		rc.Close()
		if err != nil {
			return err
		}
	}
	return nil
}

func backupPath(versionDir, relativePath, backupDir string) error {
	src := filepath.Join(versionDir, relativePath)
	if _, err := os.Stat(src); os.IsNotExist(err) {
		return nil
	}

	dst := filepath.Join(versionDir, backupDir, relativePath)
	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
		return err
	}

	info, err := os.Stat(src)
	if err != nil {
		return err
	}

	if info.IsDir() {
		return copyDir(src, dst)
	}
	return copyFile(src, dst)
}

func copyPath(src, dst string) error {
	info, err := os.Stat(src)
	if err != nil {
		return err
	}

	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
		return err
	}

	if info.IsDir() {
		return copyDir(src, dst)
	}
	return copyFile(src, dst)
}

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, in)
	return err
}

func copyDir(src, dst string) error {
	return filepath.Walk(src, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		rel, err := filepath.Rel(src, path)
		if err != nil {
			return err
		}

		target := filepath.Join(dst, rel)

		if info.IsDir() {
			return os.MkdirAll(target, 0o755)
		}
		return copyFile(path, target)
	})
}