package gsp

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

	"gopkg.in/yaml.v3"
)

var ignoredDirs = map[string]bool{
	".git":         true,
	".gsp":         true,
	"node_modules": true,
	"dist":         true,
	"build":        true,
	"bin":          true,
}

func LoadProject(root string) (*Project, error) {
	absRoot, err := filepath.Abs(root)
	if err != nil {
		return nil, err
	}
	project := &Project{
		Root:       absRoot,
		ByID:       map[string]*Unit{},
		Duplicates: map[string][]*Unit{},
	}
	manifest, err := loadManifest(absRoot)
	if err != nil {
		project.LoadIssues = append(project.LoadIssues, Issue{Level: "error", Code: "manifest_error", File: "gsp.manifest", Message: err.Error()})
	}
	project.Manifest = manifest

	var files []string
	for _, scanEntry := range project.Manifest.scanEntries() {
		scanPath := filepath.Join(absRoot, filepath.FromSlash(scanEntry))
		info, statErr := os.Stat(scanPath)
		if statErr != nil {
			project.LoadIssues = append(project.LoadIssues, Issue{Level: "warning", Code: "scan_missing", File: scanEntry, Message: "scan path does not exist"})
			continue
		}
		if !info.IsDir() {
			if strings.EqualFold(filepath.Ext(scanPath), ".gsp") {
				files = append(files, scanPath)
			}
			continue
		}
		walkErr := filepath.WalkDir(scanPath, func(path string, entry os.DirEntry, walkErr error) error {
			if walkErr != nil {
				project.LoadIssues = append(project.LoadIssues, Issue{Level: "error", Code: "walk_error", File: path, Message: walkErr.Error()})
				return nil
			}
			if entry.IsDir() {
				if ignoredDirs[entry.Name()] {
					return filepath.SkipDir
				}
				return nil
			}
			if strings.EqualFold(filepath.Ext(entry.Name()), ".gsp") {
				files = append(files, path)
			}
			return nil
		})
		if walkErr != nil {
			return nil, walkErr
		}
	}
	sort.Strings(files)

	for _, file := range files {
		unit, err := readUnit(absRoot, file)
		if err != nil {
			project.LoadIssues = append(project.LoadIssues, Issue{Level: "error", Code: "parse_error", File: relPath(absRoot, file), Message: err.Error()})
			continue
		}
		project.Units = append(project.Units, unit)
		if unit.ID == "" {
			continue
		}
		if existing, ok := project.ByID[unit.ID]; ok {
			project.Duplicates[unit.ID] = append(project.Duplicates[unit.ID], existing, unit)
			continue
		}
		project.ByID[unit.ID] = unit
	}
	return project, nil
}

func readUnit(root, file string) (*Unit, error) {
	data, err := os.ReadFile(file)
	if err != nil {
		return nil, err
	}
	var unit Unit
	if err := yaml.Unmarshal(data, &unit); err != nil {
		return nil, err
	}
	unit.File = relPath(root, file)
	return &unit, nil
}

func relPath(root, path string) string {
	rel, err := filepath.Rel(root, path)
	if err != nil {
		return path
	}
	return filepath.ToSlash(rel)
}