package collector

import (
	"os"
	"path/filepath"
	"strings"
)

// Matcher determines if a file should be included in the collection
type Matcher interface {
	ShouldInclude(path string, info os.FileInfo) bool
}

// NameMatcher matches files by exact name
type NameMatcher struct {
	name string
}

// NewNameMatcher creates a matcher for exact filename matching
func NewNameMatcher(name string) *NameMatcher {
	return &NameMatcher{name: name}
}

// ShouldInclude returns true if the file matches the exact name
func (m *NameMatcher) ShouldInclude(path string, info os.FileInfo) bool {
	if info.IsDir() {
		return false
	}
	return info.Name() == m.name
}

// PatternMatcher matches files within directories matching a glob pattern
type PatternMatcher struct {
	pattern         string
	matchedDirs     map[string]bool
	patternSegments []string
}

// NewPatternMatcher creates a matcher for directory pattern matching
func NewPatternMatcher(pattern string) *PatternMatcher {
	// Remove trailing slash if present
	pattern = strings.TrimSuffix(pattern, "/")

	return &PatternMatcher{
		pattern:         pattern,
		matchedDirs:     make(map[string]bool),
		patternSegments: strings.Split(pattern, string(os.PathSeparator)),
	}
}

// ShouldInclude returns true if the file is within a directory matching the pattern
func (m *PatternMatcher) ShouldInclude(path string, info os.FileInfo) bool {
	// For directories, check if they match the pattern and cache the result
	if info.IsDir() {
		matched, err := m.dirMatchesPattern(path)
		if err == nil && matched {
			m.matchedDirs[path] = true
		}
		return false // Don't include the directory itself, only files within
	}

	// For files, check if any parent directory is in the matched set
	dir := filepath.Dir(path)
	for {
		if m.matchedDirs[dir] {
			return true
		}

		// Also check if this directory matches the pattern (in case we haven't seen it yet)
		if matched, err := m.dirMatchesPattern(dir); err == nil && matched {
			m.matchedDirs[dir] = true
			return true
		}

		parent := filepath.Dir(dir)
		if parent == dir || parent == "." {
			break
		}
		dir = parent
	}

	return false
}

// dirMatchesPattern checks if a directory path matches the glob pattern
func (m *PatternMatcher) dirMatchesPattern(dirPath string) (bool, error) {
	// Get the directory name
	dirName := filepath.Base(dirPath)

	// For simple patterns (no path separators), just match the directory name
	if len(m.patternSegments) == 1 {
		return filepath.Match(m.pattern, dirName)
	}

	// For complex patterns, we need to match the full path segments
	pathSegments := strings.Split(dirPath, string(os.PathSeparator))

	// Try to match the pattern segments against the path segments
	if len(pathSegments) < len(m.patternSegments) {
		return false, nil
	}

	// Check each pattern segment against the corresponding path segment
	for i := 0; i < len(m.patternSegments); i++ {
		// Start from the end of both slices
		patternIdx := len(m.patternSegments) - 1 - i
		pathIdx := len(pathSegments) - 1 - i

		matched, err := filepath.Match(m.patternSegments[patternIdx], pathSegments[pathIdx])
		if err != nil {
			return false, err
		}
		if !matched {
			return false, nil
		}
	}

	return true, nil
}

// CompositeMatcher combines multiple matchers with OR logic
type CompositeMatcher struct {
	matchers []Matcher
}

// NewCompositeMatcher creates a matcher that combines multiple matchers
func NewCompositeMatcher(matchers []Matcher) *CompositeMatcher {
	return &CompositeMatcher{matchers: matchers}
}

// ShouldInclude returns true if ANY of the matchers match the file
func (m *CompositeMatcher) ShouldInclude(path string, info os.FileInfo) bool {
	for _, matcher := range m.matchers {
		if matcher.ShouldInclude(path, info) {
			return true
		}
	}
	return false
}

// DirectoryFilter determines if a directory should be traversed
type DirectoryFilter interface {
	ShouldTraverse(path string, sourceDir string) bool
}

// IncludeDirectoryFilter only traverses directories matching the patterns
type IncludeDirectoryFilter struct {
	patterns []string
}

// NewIncludeDirectoryFilter creates a filter that only includes matching directories
func NewIncludeDirectoryFilter(patterns []string) *IncludeDirectoryFilter {
	return &IncludeDirectoryFilter{patterns: patterns}
}

// ShouldTraverse returns true if the directory path matches any include pattern
func (f *IncludeDirectoryFilter) ShouldTraverse(path string, sourceDir string) bool {
	// Always traverse the source directory itself
	if path == sourceDir {
		return true
	}

	// Get relative path from source directory
	relPath, err := filepath.Rel(sourceDir, path)
	if err != nil {
		return false
	}
	relPath = filepath.ToSlash(relPath)

	// Check if this directory or any parent directory matches any pattern
	for _, pattern := range f.patterns {
		if f.pathMatchesPattern(relPath, pattern) {
			return true
		}
	}

	return false
}

// pathMatchesPattern checks if a path matches a glob pattern
func (f *IncludeDirectoryFilter) pathMatchesPattern(path, pattern string) bool {
	// Direct match
	if matched, _ := filepath.Match(pattern, path); matched {
		return true
	}

	// Check if any parent directory matches the pattern
	pathSegments := strings.Split(path, "/")
	for i := 0; i < len(pathSegments); i++ {
		segment := pathSegments[i]
		if matched, _ := filepath.Match(pattern, segment); matched {
			return true
		}
	}

	// Check if we're a subdirectory of a matching directory
	dir := filepath.Dir(path)
	for dir != "." && dir != "/" {
		if matched, _ := filepath.Match(pattern, filepath.Base(dir)); matched {
			return true
		}
		dir = filepath.Dir(dir)
	}

	return false
}

// ExcludeDirectoryFilter skips directories matching the patterns
type ExcludeDirectoryFilter struct {
	patterns []string
}

// NewExcludeDirectoryFilter creates a filter that excludes matching directories
func NewExcludeDirectoryFilter(patterns []string) *ExcludeDirectoryFilter {
	return &ExcludeDirectoryFilter{patterns: patterns}
}

// ShouldTraverse returns false if the directory path matches any exclude pattern
func (f *ExcludeDirectoryFilter) ShouldTraverse(path string, sourceDir string) bool {
	// Always traverse the source directory itself
	if path == sourceDir {
		return true
	}

	// Get relative path from source directory
	relPath, err := filepath.Rel(sourceDir, path)
	if err != nil {
		return true
	}
	relPath = filepath.ToSlash(relPath)

	// Check if this directory or any parent directory matches any exclude pattern
	for _, pattern := range f.patterns {
		if f.pathMatchesPattern(relPath, pattern) {
			return false
		}
	}

	return true
}

// pathMatchesPattern checks if a path matches a glob pattern
func (f *ExcludeDirectoryFilter) pathMatchesPattern(path, pattern string) bool {
	// Direct match
	if matched, _ := filepath.Match(pattern, path); matched {
		return true
	}

	// Check if any parent directory matches the pattern
	pathSegments := strings.Split(path, "/")
	for i := 0; i < len(pathSegments); i++ {
		segment := pathSegments[i]
		if matched, _ := filepath.Match(pattern, segment); matched {
			return true
		}
	}

	return false
}

// CompositeDirectoryFilter combines multiple directory filters
type CompositeDirectoryFilter struct {
	includeFilters []DirectoryFilter
	excludeFilters []DirectoryFilter
}

// NewCompositeDirectoryFilter creates a filter combining include and exclude filters
func NewCompositeDirectoryFilter(includeFilters, excludeFilters []DirectoryFilter) *CompositeDirectoryFilter {
	return &CompositeDirectoryFilter{
		includeFilters: includeFilters,
		excludeFilters: excludeFilters,
	}
}

// ShouldTraverse applies include filters first, then exclude filters
// Include filters take precedence when both are present
func (f *CompositeDirectoryFilter) ShouldTraverse(path string, sourceDir string) bool {
	// If we have include filters, the directory must match at least one
	if len(f.includeFilters) > 0 {
		shouldInclude := false
		for _, filter := range f.includeFilters {
			if filter.ShouldTraverse(path, sourceDir) {
				shouldInclude = true
				break
			}
		}
		if !shouldInclude {
			return false
		}
	}

	// Apply exclude filters
	for _, filter := range f.excludeFilters {
		if !filter.ShouldTraverse(path, sourceDir) {
			return false
		}
	}

	return true
}