package main

import (
	"bytes"
	"fmt"
	"go/format"
	"os"
	"slices"
	"strings"

	"github.com/coder/coder/v2/coderd/rbac"
	"github.com/coder/coder/v2/coderd/rbac/policy"
)

func main() {
	out, err := generate()
	if err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "generate apikey scopes: %v\n", err)
		os.Exit(1)
	}
	if _, err := fmt.Print(string(out)); err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "write output: %v\n", err)
		os.Exit(1)
	}
}

func generate() ([]byte, error) {
	allNames := collectAllScopeNames()
	publicNames := rbac.ExternalScopeNames()

	var b bytes.Buffer
	if _, err := b.WriteString("// Code generated by scripts/apikeyscopesgen. DO NOT EDIT.\n"); err != nil {
		return nil, err
	}
	if _, err := b.WriteString("package codersdk\n\n"); err != nil {
		return nil, err
	}
	// NOTE: Keep all APIKeyScope constants in a single generated file.
	// Some tooling (e.g. swaggo) can behave non-deterministically when
	// enums are spread across multiple files:
	//   https://github.com/swaggo/swag/issues/2038
	// We generate everything into codersdk/apikey_scopes_gen.go as the
	// single source of truth so doc generation remains stable.

	// Constants
	if _, err := b.WriteString("const (\n"); err != nil {
		return nil, err
	}
	// Always include legacy/deprecated aliases for backward compatibility.
	// These are kept in generated code to ensure consistent availability
	// across releases even if hand-written files change.
	if _, err := b.WriteString("\t// Deprecated: use codersdk.APIKeyScopeCoderAll instead.\n"); err != nil {
		return nil, err
	}
	if _, err := b.WriteString("\tAPIKeyScopeAll APIKeyScope = \"all\"\n"); err != nil {
		return nil, err
	}
	if _, err := b.WriteString("\t// Deprecated: use codersdk.APIKeyScopeCoderApplicationConnect instead.\n"); err != nil {
		return nil, err
	}
	if _, err := b.WriteString("\tAPIKeyScopeApplicationConnect APIKeyScope = \"application_connect\"\n"); err != nil {
		return nil, err
	}
	for _, name := range allNames {
		constName := constNameForScope(name)
		if _, err := fmt.Fprintf(&b, "\t%s APIKeyScope = \"%s\"\n", constName, name); err != nil {
			return nil, err
		}
	}
	if _, err := b.WriteString(")\n\n"); err != nil {
		return nil, err
	}

	// Slices
	if _, err := b.WriteString("// PublicAPIKeyScopes lists all public low-level API key scopes.\n"); err != nil {
		return nil, err
	}
	if _, err := b.WriteString("var PublicAPIKeyScopes = []APIKeyScope{\n"); err != nil {
		return nil, err
	}
	for _, name := range publicNames {
		constName := constNameForScope(name)
		if _, err := fmt.Fprintf(&b, "\t%s,\n", constName); err != nil {
			return nil, err
		}
	}
	if _, err := b.WriteString("}\n\n"); err != nil {
		return nil, err
	}

	return format.Source(b.Bytes())
}

func collectAllScopeNames() []string {
	seen := make(map[string]struct{})
	var names []string
	add := func(name string) {
		if name == "" {
			return
		}
		if _, ok := seen[name]; ok {
			return
		}
		seen[name] = struct{}{}
		names = append(names, name)
	}

	for resource, def := range policy.RBACPermissions {
		if resource == policy.WildcardSymbol {
			continue
		}
		add(resource + ":" + policy.WildcardSymbol)
		for action := range def.Actions {
			add(resource + ":" + string(action))
		}
	}

	for _, name := range rbac.CompositeScopeNames() {
		add(name)
	}

	for _, name := range rbac.BuiltinScopeNames() {
		s := string(name)
		if !strings.Contains(s, ":") {
			continue
		}
		add(s)
	}

	slices.Sort(names)
	return names
}

func constNameForScope(name string) string {
	resource, action := splitRA(name)
	if action == policy.WildcardSymbol {
		action = "All"
	}
	return fmt.Sprintf("APIKeyScope%s%s", pascal(resource), pascal(action))
}

func splitRA(name string) (resource string, action string) {
	parts := strings.SplitN(name, ":", 2)
	if len(parts) != 2 {
		return name, ""
	}
	return parts[0], parts[1]
}

func pascal(s string) string {
	// Replace non-identifier separators with spaces, then Title-case and strip.
	s = strings.ReplaceAll(s, "_", " ")
	s = strings.ReplaceAll(s, "-", " ")
	s = strings.ReplaceAll(s, ":", " ")
	s = strings.ReplaceAll(s, ".", " ")
	words := strings.Fields(s)
	for i := range words {
		words[i] = strings.ToUpper(words[i][:1]) + words[i][1:]
	}
	return strings.Join(words, "")
}