package main

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"gopkg.in/yaml.v3"
)

// ops_docs_gen: builds per-service operations docs from resources_ops_yaml.
//
// Env:
// - NUBES_OPS_YAML_DIR (default: <repo>/resources_ops_yaml)
// - NUBES_OPS_DOCS_DIR (default: <repo>/../docs/30_registry/resources/operations)

func main() {
	repoRoot, err := findRepoRoot()
	if err != nil {
		panic(err)
	}

	yamlDir := strings.TrimSpace(os.Getenv("NUBES_OPS_YAML_DIR"))
	if yamlDir == "" {
		yamlDir = filepath.Join(repoRoot, "resources_ops_yaml")
	}

	docsDir := strings.TrimSpace(os.Getenv("NUBES_OPS_DOCS_DIR"))
	if docsDir == "" {
		root := filepath.Dir(repoRoot)
		docsDir = filepath.Join(root, "docs", "30_registry", "resources", "operations")
	}

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

	entries := []docEntry{}

	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 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, sanitizeName(spec.Name))
		outPath := filepath.Join(docsDir, fileName)
		if err := writeServiceDoc(outPath, spec); err != nil {
			return err
		}

		entries = append(entries, docEntry{
			ServiceID: spec.ServiceID,
			Name:      spec.Name,
			File:      fileName,
			Title:     serviceTitle(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 := writeIndex(filepath.Join(docsDir, "index.md"), entries); err != nil {
		panic(err)
	}

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

type docEntry struct {
	ServiceID int
	Name      string
	File      string
	Title     string
	OpCount   int
}

func writeServiceDoc(path string, spec ServiceOpsSpec) error {
	var b strings.Builder
	b.WriteString(fmt.Sprintf("# Operations for nubes_%s\n\n", spec.Name))
	b.WriteString(fmt.Sprintf("Service ID: `%d`\n\n", spec.ServiceID))

	if title := serviceTitle(spec); title != "" {
		b.WriteString(fmt.Sprintf("Service: %s\n\n", title))
	}

	if strings.TrimSpace(spec.ServiceMan) != "" {
		b.WriteString("## UI description\n\n")
		b.WriteString(spec.ServiceMan)
		b.WriteString("\n\n")
	}

	b.WriteString("## Operations\n\n")
	b.WriteString("Non-CRUD operations are typically executed via an action resource.\n")
	b.WriteString("Domain operations (for example create_user, create_database) are best modeled as separate resources.\n\n")
	if len(spec.Operations) == 0 {
		b.WriteString("No operations found.\n")
		return os.WriteFile(path, []byte(b.String()), 0o644)
	}

	for _, op := range spec.Operations {
		b.WriteString(fmt.Sprintf("- `%s` (id: %d)\n", op.Name, op.ID))
	}
	b.WriteString("\n")

	for _, op := range spec.Operations {
		b.WriteString(fmt.Sprintf("## Operation: %s\n\n", op.Name))
		b.WriteString(fmt.Sprintf("Operation ID: `%d`\n\n", op.ID))
		if strings.TrimSpace(op.Man) != "" {
			b.WriteString(op.Man)
			b.WriteString("\n\n")
		}
		if len(op.Params) == 0 {
			b.WriteString("No parameters.\n\n")
			continue
		}

		b.WriteString("| Code | Type | Required | Default | ID | RefSvcId | ValueList | Func | Regex | Min | Max | Sensitive | DependsOn |\n")
		b.WriteString("|---|---|---|---|---|---|---|---|---|---|---|---|---|\n")
		for _, p := range op.Params {
			b.WriteString(fmt.Sprintf("| `%s` | `%s` | `%t` | `%s` | `%d` | `%s` | `%s` | `%s` | `%s` | `%s` | `%s` | `%t` | `%s` |\n",
				esc(p.Code),
				esc(p.DataType),
				p.Required,
				esc(formatValue(p.Default)),
				p.ID,
				esc(formatRef(p.RefSvcId)),
				esc(formatList(p.ValueList)),
				esc(p.Func),
				esc(p.Regex),
				esc(formatValue(p.MinValue)),
				esc(formatValue(p.MaxValue)),
				p.IsSensitive,
				esc(formatValue(p.DependsOn)),
			))
		}
		b.WriteString("\n")
	}

	return os.WriteFile(path, []byte(b.String()), 0o644)
}

func writeIndex(path string, entries []docEntry) error {
	var b strings.Builder
	b.WriteString("# Operations by service\n\n")
	b.WriteString("Auto-generated list of available operations per service.\n\n")
	b.WriteString("Note: non-CRUD operations should be invoked via an action resource,\n")
	b.WriteString("and domain operations are best represented as dedicated resources.\n\n")
	for _, e := range entries {
		b.WriteString(fmt.Sprintf("- %d - nubes_%s (%d ops): [%s](%s)\n", e.ServiceID, e.Name, e.OpCount, e.Title, e.File))
	}
	return os.WriteFile(path, []byte(b.String()), 0o644)
}

func sanitizeName(name string) string {
	name = strings.ToLower(strings.TrimSpace(name))
	name = strings.ReplaceAll(name, " ", "_")
	name = strings.ReplaceAll(name, "/", "_")
	name = strings.ReplaceAll(name, "\\", "_")
	name = strings.ReplaceAll(name, ":", "_")
	name = strings.ReplaceAll(name, "-", "_")
	return name
}

func serviceTitle(spec ServiceOpsSpec) string {
	if strings.TrimSpace(spec.ServiceDisplayName) != "" {
		return spec.ServiceDisplayName
	}
	if strings.TrimSpace(spec.ServiceShortName) != "" {
		return spec.ServiceShortName
	}
	return ""
}

func formatList(items []string) string {
	if len(items) == 0 {
		return ""
	}
	return strings.Join(items, ",")
}

func formatRef(value *int) string {
	if value == nil {
		return ""
	}
	return fmt.Sprintf("%d", *value)
}

func formatValue(value interface{}) string {
	if value == nil {
		return ""
	}
	switch t := value.(type) {
	case string:
		return t
	default:
		b, err := json.Marshal(t)
		if err != nil {
			return fmt.Sprintf("%v", value)
		}
		return string(b)
	}
}

func esc(value string) string {
	return strings.ReplaceAll(value, "|", "\\|")
}

func findRepoRoot() (string, error) {
	wd, err := os.Getwd()
	if err != nil {
		return "", err
	}
	current := wd
	for i := 0; i < 8; i++ {
		candidate := filepath.Join(current, "resources_yaml")
		info, err := os.Stat(candidate)
		if err == nil && info.IsDir() {
			return current, nil
		}
		parent := filepath.Dir(current)
		if parent == current {
			break
		}
		current = parent
	}
	return "", fmt.Errorf("failed to locate universal_rebuild repo root")
}

// ===== spec =====

type ServiceOpsSpec struct {
	Name               string          `yaml:"name"`
	ServiceID          int             `yaml:"service_id"`
	ServiceDisplayName string          `yaml:"service_display_name,omitempty"`
	ServiceShortName   string          `yaml:"service_short_name,omitempty"`
	ServiceMan         string          `yaml:"service_man,omitempty"`
	Operations         []OperationSpec `yaml:"operations"`
}

type OperationSpec struct {
	Name   string      `yaml:"name"`
	ID     int         `yaml:"id"`
	Man    string      `yaml:"man,omitempty"`
	Params []ParamSpec `yaml:"params"`
}

type ParamSpec struct {
	ID           int         `yaml:"id"`
	Code         string      `yaml:"code"`
	DataType     string      `yaml:"data_type,omitempty"`
	Required     bool        `yaml:"required"`
	Default      interface{} `yaml:"default,omitempty"`
	ValueList    []string    `yaml:"value_list,omitempty"`
	RefSvcId     *int        `yaml:"ref_svc_id,omitempty"`
	Func         string      `yaml:"func,omitempty"`
	Regex        string      `yaml:"regex,omitempty"`
	UniqueScope  string      `yaml:"unique_scope,omitempty"`
	MaxLength    *int        `yaml:"maxlength,omitempty"`
	MinLength    *int        `yaml:"minlength,omitempty"`
	MaxValue     interface{} `yaml:"maxvalue,omitempty"`
	MinValue     interface{} `yaml:"minvalue,omitempty"`
	Descr        string      `yaml:"descr,omitempty"`
	Man          string      `yaml:"man,omitempty"`
	Sort         *int        `yaml:"sort,omitempty"`
	DependsOn    interface{} `yaml:"depends_on,omitempty"`
	IsModifiable *bool       `yaml:"is_modifiable,omitempty"`
	IsSensitive  bool        `yaml:"is_sensitive,omitempty"`
}