package tree

import (
	"fmt"
	"io/fs"
	"path/filepath"
	"strings"

	"git.flo.fo/FLO/dirmd/internal/config"
	"git.flo.fo/FLO/dirmd/internal/filter"
)

func BuildFullTree(absRoot string, cfg *config.Config) (*Node, error) {
	root := &Node{IsDir: true, Children: make(map[string]*Node)}

	err := filepath.WalkDir(absRoot, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return nil
		}

		rel, rerr := filepath.Rel(absRoot, path)
		if rerr != nil || rel == "." {
			return nil
		}

		if filter.IsSymlink(path) {
			return nil
		}

		depth := strings.Count(rel, string(filepath.Separator)) + 1
		if depth > cfg.MaxDepth {
			node := addPath(root, rel, d.IsDir())
			node.Annotation = "exceeded --max-depth"
			if d.IsDir() {
				return filepath.SkipDir
			}
			return nil
		}

		name := filepath.Base(path)

		if d.IsDir() {
			if isIgnoredName(name, cfg.Ignores) {
				node := addPath(root, rel, true)
				node.Annotation = "ignored (--ignore)"
				return filepath.SkipDir
			}
			if cfg.OmitTest && isTestDir(rel) {
				node := addPath(root, rel, true)
				node.Annotation = "tests omitted (--omit-test)"
				return filepath.SkipDir
			}
			addPath(root, rel, true)
			return nil
		}

		if annotation, ok := fileAnnotation(rel, name, cfg); ok {
			node := addPath(root, rel, false)
			node.Annotation = annotation
			return nil
		}

		addPath(root, rel, false)
		return nil
	})
	if err != nil {
		return nil, fmt.Errorf("cannot walk %s: %w", absRoot, err)
	}

	return root, nil
}

func isIgnoredName(name string, ignores []string) bool {
	if strings.HasPrefix(name, ".") {
		return true
	}
	for _, pattern := range ignores {
		if matched, _ := filepath.Match(pattern, name); matched {
			return true
		}
	}
	return false
}

func isTestDir(rel string) bool {
	slashPath := filepath.ToSlash(rel)
	return strings.Contains(slashPath, "/tests/") || strings.HasPrefix(slashPath, "tests/")
}

func fileAnnotation(rel, name string, cfg *config.Config) (string, bool) {
	if strings.HasPrefix(name, ".") {
		return "", false
	}
	for _, pattern := range cfg.Ignores {
		if matched, _ := filepath.Match(pattern, name); matched {
			return "ignored (--ignore)", true
		}
	}
	if cfg.OmitTest && isTestFileName(rel, name) {
		return "tests omitted (--omit-test)", true
	}
	if cfg.OmitMd && isNonReadmeMarkdown(name) {
		return "omitted (--omit-md)", true
	}
	if cfg.FrontendOnly && !isFrontendOrReadme(rel, name) {
		return "omitted (--frontend-only)", true
	}
	if cfg.SkipFrontend && isFrontendExt(rel) {
		return "omitted (--skip-frontend)", true
	}
	return "", false
}

func isTestFileName(rel, name string) bool {
	ext := strings.ToLower(filepath.Ext(name))
	switch ext {
	case ".go":
		return strings.HasSuffix(strings.ToLower(name), "_test.go")
	case ".java":
		base := strings.TrimSuffix(name, filepath.Ext(name))
		if strings.HasSuffix(base, "Test") || strings.HasSuffix(base, "Tests") {
			return true
		}
		slashPath := filepath.ToSlash(rel)
		return strings.Contains(slashPath, "/src/test/")
	case ".py":
		lower := strings.ToLower(name)
		if strings.HasPrefix(lower, "test_") || strings.HasSuffix(lower, "_test.py") {
			return true
		}
		if strings.EqualFold(name, "conftest.py") {
			return true
		}
		return isTestDir(rel)
	}
	return false
}

func isNonReadmeMarkdown(name string) bool {
	ext := strings.ToLower(filepath.Ext(name))
	if ext != ".md" && ext != ".markdown" {
		return false
	}
	return !strings.EqualFold(name, "README.md")
}

func isFrontendOrReadme(rel, name string) bool {
	if isFrontendExt(rel) {
		return true
	}
	return strings.EqualFold(name, "README.md")
}

func isFrontendExt(rel string) bool {
	ext := strings.ToLower(filepath.Ext(rel))
	for _, fe := range frontendExts {
		if strings.EqualFold(ext, fe) {
			return true
		}
	}
	return false
}

var frontendExts = []string{
	".html", ".htm", ".gohtml", ".tmpl",
	".css", ".scss", ".sass", ".less",
	".js", ".jsx", ".mjs", ".cjs",
	".ts", ".tsx",
	".vue", ".svelte",
}