package state

import (
	"errors"
	"fmt"
	"net/url"
	"path/filepath"
	"sort"
	"strings"

	"go.uber.org/zap"

	"github.com/helmfile/helmfile/pkg/filesystem"
	"github.com/helmfile/helmfile/pkg/remote"
)

type Storage struct {
	logger *zap.SugaredLogger

	FilePath string

	basePath string
	fs       *filesystem.FileSystem
}

func NewStorage(forFile string, logger *zap.SugaredLogger, fs *filesystem.FileSystem) *Storage {
	return &Storage{
		FilePath: forFile,
		basePath: filepath.Dir(forFile),
		logger:   logger,
		fs:       fs,
	}
}

type resolveFileConfig struct {
	IgnoreMissingGitBranch bool
}

type resolveFileOption func(*resolveFileConfig)

func ignoreMissingGitBranch(v bool) func(c *resolveFileConfig) {
	return func(c *resolveFileConfig) {
		c.IgnoreMissingGitBranch = v
	}
}

func (st *Storage) resolveFile(missingFileHandler *string, tpe, path string, opts ...resolveFileOption) ([]string, bool, error) {
	title := fmt.Sprintf("%s file", tpe)

	var (
		files []string
		err   error
		conf  resolveFileConfig
	)

	for _, o := range opts {
		o(&conf)
	}

	if remote.IsRemote(path) {
		r := remote.NewRemote(st.logger, "", st.fs)

		// Named fetchErr, not err: err is declared in the outer scope above and
		// checked again after this if-block. Reusing that name here would shadow
		// it with a new, block-local variable (fetchedFilePath is new, so ":="
		// can't reuse the outer err), silently discarding any fetch error that
		// isn't returned or explicitly ignored below.
		fetchedFilePath, fetchErr := r.Fetch(path, "values")
		if fetchErr != nil {
			// https://github.com/helmfile/helmfile/issues/392
			if conf.IgnoreMissingGitBranch && strings.Contains(fetchErr.Error(), "' did not match any file(s) known to git") {
				st.logger.Debugf("Ignored missing git branch error: %v", fetchErr)
			} else {
				return nil, false, fetchErr
			}
		}

		switch {
		case fetchedFilePath == "":
			// Fetch failed and the failure was ignored above (ignoreMissingGitBranch).
			// Leave files empty and let the missing file handler below decide.
		case st.fs.FileExistsAt(fetchedFilePath):
			// A literal, existing file. Checked before glob-expanding so that a
			// file name which happens to contain "[" or "?" (valid in
			// filepath.Match patterns but also valid in plain file names) still
			// resolves to itself when it exists.
			files = []string{fetchedFilePath}
		case remote.HasGlobPattern(path):
			// Fetch joins the "@<file>" selector onto the local cache directory
			// verbatim (see Remote.Fetch), so a wildcard selector is expanded
			// here, against the fetched directory, using the same glob syntax as
			// local values files (st.ExpandPaths / filepath.Match).
			//
			// st.ExpandPaths itself is not reused: its normalizePath would
			// incorrectly prefix the helmfile's basePath onto this
			// already-absolute cache path whenever remote.CacheDir() falls back
			// to the relative ".helmfile" directory.
			matches, globErr := st.fs.Glob(fetchedFilePath)
			if globErr != nil {
				// filepath.Glob's only documented error is ErrBadPattern (e.g. an
				// unclosed "["). Before wildcard support, a selector containing "["
				// was checked with FileExistsAt and simply treated as missing if it
				// didn't exist, so a malformed pattern should fall back to the same
				// missingFileHandler-driven "no matches" handling below rather than
				// becoming an unconditional hard error, which would be a regression
				// for existing Info/Warn/Debug users referencing such a file.
				if !errors.Is(globErr, filepath.ErrBadPattern) {
					return nil, false, fmt.Errorf("failed processing %s: %v", path, globErr)
				}
				st.logger.Debugf("Treating invalid glob pattern as no match for %s: %v", path, globErr)
			}
			sort.Strings(matches)
			for _, m := range matches {
				// Keep the same "regular files only" contract as the non-glob
				// case above: a glob can also match directories.
				if st.fs.FileExistsAt(m) {
					files = append(files, m)
				}
			}
		}
	} else {
		files, err = st.ExpandPaths(path)
	}

	if err != nil {
		return nil, false, err
	}

	var handlerId string

	if missingFileHandler != nil {
		handlerId = *missingFileHandler
	} else {
		handlerId = MissingFileHandlerError
	}

	if len(files) == 0 {
		switch handlerId {
		case MissingFileHandlerError:
			return nil, false, fmt.Errorf("%s matching \"%s\" does not exist in \"%s\"", title, path, st.basePath)
		case MissingFileHandlerWarn:
			st.logger.Warnf("skipping missing %s matching \"%s\"", title, path)
			return nil, true, nil
		case MissingFileHandlerInfo:
			st.logger.Infof("skipping missing %s matching \"%s\"", title, path)
			return nil, true, nil
		case MissingFileHandlerDebug:
			st.logger.Debugf("skipping missing %s matching \"%s\"", title, path)
			return nil, true, nil
		default:
			available := []string{
				MissingFileHandlerError,
				MissingFileHandlerWarn,
				MissingFileHandlerInfo,
				MissingFileHandlerDebug,
			}
			return nil, false, fmt.Errorf("invalid missing file handler \"%s\" while processing \"%s\" in \"%s\": it must be one of %s", handlerId, path, st.FilePath, available)
		}
	}

	return files, false, nil
}

func (st *Storage) ExpandPaths(globPattern string) ([]string, error) {
	result := []string{}
	absPathPattern := st.normalizePath(globPattern)
	matches, err := st.fs.Glob(absPathPattern)
	if err != nil {
		return nil, fmt.Errorf("failed processing %s: %v", globPattern, err)
	}

	sort.Strings(matches)

	result = append(result, matches...)
	return result, nil
}

// normalizes relative path to absolute one
func (st *Storage) normalizePath(path string) string {
	u, _ := url.Parse(path)
	if u != nil && (u.Scheme != "" || filepath.IsAbs(path)) {
		return path
	}
	// Avoid double-prefixing when the path already starts with basePath.
	// This can happen when normalizePath is called multiple times on the same path
	// (e.g. once in generateVanillaValuesFiles and again in resolveFile/ExpandPaths).
	if st.basePath != "" && st.basePath != "." && strings.HasPrefix(path, st.basePath+string(filepath.Separator)) {
		return path
	}
	return st.JoinBase(path)
}

// JoinBase returns an absolute path in the form basePath/relative
// Helm's setFiles command does not support unescaped filepath separators (\) on Windows.
// Instead, it requires double backslashes (\\) as filepath separators.
// See https://github.com/helm/helm/issues/9537
func (st *Storage) JoinBase(relPath string) string {
	path := filepath.Join(st.basePath, relPath)
	return path
}

func (st *Storage) normalizeSetFilePath(path, goos string) string {
	normalizedPath := st.normalizePath(path)
	if goos == "windows" {
		return strings.ReplaceAll(normalizedPath, "\\", "\\\\")
	}
	return normalizedPath
}