// docs-generator — генератор Markdown-документации для ресурсов провайдера.
package main

import (
	"flag"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"

	"gopkg.in/yaml.v3"

	"docs-generator/internal/ops"
	"docs-generator/internal/types"
	"docs-generator/internal/writers"
)

func main() {
	resourcesDirFlag := flag.String("resources", "", "Path to resources_yaml")
	docsDirFlag := flag.String("docs", "", "Path to docs/30_registry/resources")
	servicesListFlag := flag.String("services", "", "Path to devops/config/services_list.txt")
	excludeFlag := flag.String("exclude", "", "Comma-separated resource names to skip")
	versionFlag := flag.String("version", "", "Provider version for example block")
	apiEndpointFlag := flag.String("api-endpoint", "https://deck-api.ngcloud.ru/api/v1/index.cfm", "API endpoint for example block")
	opsFlag := flag.Bool("ops", false, "Generate per-service operations docs (resources_ops_yaml → docs/.../operations)")
	flag.Parse()

	root := detectRoot()

	// --ops mode: generate per-service operations documentation
	if *opsFlag {
		runOpsMode(root)
		return
	}
	resourcesDir := pickPath(*resourcesDirFlag, filepath.Join(root, "provider", "resources_yaml"))
	docsDir := pickPath(*docsDirFlag, filepath.Join(root, "docs", "30_registry", "resources"))
	servicesList := pickPath(*servicesListFlag, filepath.Join(root, "devops", "config", "services_list.txt"))
	writers.CloudOutputByServiceID = writers.LoadCloudOutputSnapshot(root)
	excludeSet := toSet(*excludeFlag)
	version := *versionFlag
	if version == "" {
		version = detectVersion(filepath.Join(root, "provider", "main.go"))
	}
	apiEndpoint := *apiEndpointFlag

	servicesOrder := loadServicesList(servicesList)
	specs := loadSpecs(resourcesDir, servicesOrder)
	if len(specs) == 0 {
		fmt.Fprintf(os.Stderr, "No specs found in %s\n", resourcesDir)
		os.Exit(1)
	}

	if err := os.MkdirAll(docsDir, 0o755); err != nil {
		fmt.Fprintf(os.Stderr, "ERROR: cannot create docs dir %s: %v\n", docsDir, err)
		os.Exit(1)
	}

	var processedSpecs []types.ServiceSpec
	for _, spec := range specs {
		if excludeSet[spec.Name] {
			continue
		}
		writers.ResourceDocs(docsDir, spec, version, apiEndpoint)
		processedSpecs = append(processedSpecs, spec)
	}
	writers.IndexMD(docsDir, processedSpecs)
}

func detectRoot() string {
	cwd, err := os.Getwd()
	if err != nil {
		panic(err)
	}
	if filepath.Base(cwd) == "provider" {
		return filepath.Dir(cwd)
	}
	return cwd
}

func pickPath(value, fallback string) string {
	if value != "" {
		return value
	}
	return fallback
}

func toSet(csv string) map[string]bool {
	out := map[string]bool{}
	for _, item := range strings.Split(csv, ",") {
		trimmed := strings.TrimSpace(item)
		if trimmed == "" {
			continue
		}
		out[trimmed] = true
	}
	return out
}

func detectVersion(mainPath string) string {
	b, err := os.ReadFile(mainPath)
	if err != nil {
		return "2.x"
	}
	re := regexp.MustCompile(`version string\s*=\s*"([0-9.]+)"`)
	match := re.FindStringSubmatch(string(b))
	if len(match) > 1 {
		return match[1]
	}
	return "2.x"
}

func loadServicesList(path string) []types.ServiceMeta {
	b, err := os.ReadFile(path)
	if err != nil {
		return nil
	}
	lines := strings.Split(string(b), "\n")
	out := []types.ServiceMeta{}
	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		head := strings.SplitN(line, "#", 2)[0]
		parts := strings.Fields(head)
		if len(parts) < 2 {
			continue
		}
		id, err := strconv.Atoi(parts[0])
		if err != nil {
			continue
		}
		out = append(out, types.ServiceMeta{ID: id, Name: parts[1]})
	}
	return out
}

func loadSpecs(dir string, ordered []types.ServiceMeta) []types.ServiceSpec {
	specsByID := map[int]types.ServiceSpec{}
	filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() || !strings.HasSuffix(d.Name(), ".yaml") {
			return nil
		}
		b, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		var spec types.ServiceSpec
		if err := yaml.Unmarshal(b, &spec); err != nil {
			return err
		}
		specsByID[spec.ServiceID] = spec
		return nil
	})

	if len(ordered) == 0 {
		specs := make([]types.ServiceSpec, 0, len(specsByID))
		for _, spec := range specsByID {
			specs = append(specs, spec)
		}
		sort.Slice(specs, func(i, j int) bool { return specs[i].ServiceID < specs[j].ServiceID })
		return specs
	}

	specs := []types.ServiceSpec{}
	for _, meta := range ordered {
		spec, ok := specsByID[meta.ID]
		if !ok {
			continue
		}
		specs = append(specs, spec)
	}
	return specs
}

// runOpsMode генерирует per-service operations документацию.
func runOpsMode(root string) {
	yamlDir := pickPath(os.Getenv("NUBES_OPS_YAML_DIR"), filepath.Join(root, "provider", "resources_ops_yaml"))
	docsDir := pickPath(os.Getenv("NUBES_OPS_DOCS_DIR"), filepath.Join(root, "docs", "30_registry", "resources", "operations"))

	if err := os.MkdirAll(docsDir, 0o755); err != nil {
		panic(err)
	}

	entries := []ops.Entry{}

	err := filepath.WalkDir(yamlDir, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() || !strings.HasSuffix(d.Name(), ".yaml") {
			return nil
		}
		b, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		var spec ops.ServiceOpsSpec
		if err := yaml.Unmarshal(b, &spec); err != nil {
			return err
		}
		if spec.ServiceID == 0 || spec.Name == "" {
			return nil
		}

		fileName := fmt.Sprintf("%d_%s.md", spec.ServiceID, ops.Name(spec.Name))
		outPath := filepath.Join(docsDir, fileName)
		if err := ops.ServiceDoc(outPath, spec); err != nil {
			return err
		}

		entries = append(entries, ops.Entry{
			ServiceID: spec.ServiceID,
			Name:      spec.Name,
			File:      fileName,
			Title:     ops.Title(spec),
			OpCount:   len(spec.Operations),
		})
		return nil
	})
	if err != nil {
		panic(err)
	}

	sort.Slice(entries, func(i, j int) bool { return entries[i].ServiceID < entries[j].ServiceID })
	if err := ops.Index(filepath.Join(docsDir, "index.md"), entries); err != nil {
		panic(err)
	}

	fmt.Printf("Generated %d operations docs in %s\n", len(entries), docsDir)
}