package cabana

import (
	"bytes"
	"encoding/json"
	"log/slog"
	"net/http"
	"strings"
	"time"

	"git.golem15.com/golem15/summercms/modules/bouncer"
	"git.golem15.com/golem15/summercms/modules/pact"
	"gorm.io/gorm"
)

// BackendUserRole is the Winter backend_user_roles row.
type BackendUserRole struct {
	ID          uint      `gorm:"column:id;primaryKey"`
	Name        string    `gorm:"column:name"`
	Code        string    `gorm:"column:code"`
	Description string    `gorm:"column:description"`
	Permissions string    `gorm:"column:permissions"`
	IsSystem    bool      `gorm:"column:is_system"`
	CreatedAt   time.Time `gorm:"column:created_at"`
	UpdatedAt   time.Time `gorm:"column:updated_at"`
}

func (BackendUserRole) TableName() string { return "backend_user_roles" }

// BackendUser is the Winter backend_users row. It is not a frontend user.
// Nullable Winter columns are mapped so a copied row round-trips without a
// schema transform. TokensValidAfter is the admin reset cutoff, not a Winter column.
type BackendUser struct {
	ID                uint           `gorm:"column:id;primaryKey"`
	FirstName         string         `gorm:"column:first_name"`
	LastName          string         `gorm:"column:last_name"`
	Login             string         `gorm:"column:login"`
	Email             string         `gorm:"column:email"`
	Password          string         `gorm:"column:password"`
	ActivationCode    string         `gorm:"column:activation_code"`
	PersistCode       string         `gorm:"column:persist_code"`
	ResetPasswordCode string         `gorm:"column:reset_password_code"`
	Permissions       string         `gorm:"column:permissions"`
	IsActivated       bool           `gorm:"column:is_activated"`
	IsSuperuser       bool           `gorm:"column:is_superuser"`
	RoleID            *uint          `gorm:"column:role_id"`
	ActivatedAt       *time.Time     `gorm:"column:activated_at"`
	LastLogin         *time.Time     `gorm:"column:last_login"`
	CreatedAt         time.Time      `gorm:"column:created_at"`
	UpdatedAt         time.Time      `gorm:"column:updated_at"`
	DeletedAt         gorm.DeletedAt `gorm:"column:deleted_at"`
	TokensValidAfter  *time.Time     `gorm:"column:tokens_valid_after"`
	Role              BackendUserRole
}

func (BackendUser) TableName() string { return "backend_users" }

// Option is a dropdown choice shared with later schema plans.
type Option = pact.Option

// WritableField is one schema field bound to a model fill key at activation.
// FillKey comes from the model column, not from request JSON.
type WritableField struct {
	Name    string
	FillKey string
}

// CompiledController is one admin controller after YAML compilation.
type CompiledController struct {
	PluginID   string
	Controller pact.AdminController
	List       *ListSchema
	Form       *FormSchema
	Relations  map[string]*CompiledRelation
	Writable   []WritableField
	// FieldRelations are the form's `type: relation` fields keyed by field name.
	FieldRelations map[string]*CompiledFieldRelation
	// Actions are the controller's pact.HasAdminActions entries keyed by name:
	// the single namespace that toolbar.buttons names and widget action: keys
	// resolve through. create and delete are reserved built-in names.
	Actions map[string]pact.AdminAction

	// scripts and styles are the controller's declared plugin JS and CSS,
	// in declared order.
	scripts []*pluginAsset
	styles  []*pluginAsset
	// partials are the parsed controller partials (headerPartial and every
	// `type: partial` path) keyed by name; formPartials are the names form
	// fields declare, the only ones a request may render with a record id.
	partials     map[string]*compiledPartial
	formPartials map[string]bool
}

// Registry is the immutable controller map keyed by controller ID.
type Registry struct {
	byID        map[string]*CompiledController
	permissions map[string]pact.Permission
	roleGrants  map[string]map[string]bool
	navigation  []pact.NavigationItem
	settings    map[string]*CompiledSetting
	// assets are every controller's declared plugin files keyed by URL tail
	// (vendor/plugin/<path after assets/>); the asset route serves only these.
	assets map[string]*pluginAsset
}

// Get returns the compiled controller for a D-09 id (vendor.plugin.controller).
func (r *Registry) Get(id string) (*CompiledController, bool) {
	if r == nil {
		return nil, false
	}
	cc, ok := r.byID[id]
	return cc, ok && cc != nil
}

// Setting returns one compiled singleton setting by stable code.
func (r *Registry) Setting(code string) (*CompiledSetting, bool) {
	if r == nil {
		return nil, false
	}
	setting, ok := r.settings[code]
	return setting, ok && setting != nil
}

// Allows reports whether principal satisfies any of the required permission
// codes, the way Winter's hasAnyAccess does. A nil principal fails. Superusers
// pass. An empty requirement list allows any authenticated principal. Both
// sides may use a wildcard: a grant ending in ".*" covers every code with that
// prefix, and a required code ending in ".*" (or starting with "*") is met by
// any granted code that matches it.
func Allows(principal *bouncer.Principal, required []string) bool {
	if principal == nil {
		return false
	}
	if principal.IsSuperuser || len(required) == 0 {
		return true
	}
	for _, code := range required {
		if granted(principal.PermissionGrants, code) {
			return true
		}
	}
	return false
}

// granted ports Winter's User::hasPermission for one code. Only enabled
// grants are in the map, so the "(int) $value === 1" test is already applied.
func granted(grants map[string]bool, code string) bool {
	switch {
	case len(code) > 1 && strings.HasSuffix(code, "*"):
		prefix := strings.TrimSuffix(code, "*")
		for key, on := range grants {
			if on && key != prefix && strings.HasPrefix(key, prefix) {
				return true
			}
		}
		return false
	case len(code) > 1 && strings.HasPrefix(code, "*"):
		suffix := strings.TrimPrefix(code, "*")
		for key, on := range grants {
			if on && key != suffix && strings.HasSuffix(key, suffix) {
				return true
			}
		}
		return false
	}
	if grants[code] {
		return true
	}
	for key, on := range grants {
		if !on || len(key) < 2 || !strings.HasSuffix(key, "*") {
			continue
		}
		prefix := strings.TrimSuffix(key, "*")
		if prefix != code && strings.HasPrefix(code, prefix) {
			return true
		}
	}
	return false
}

func requiredOf(ctl pact.AdminController) []string {
	if p, ok := ctl.(pact.AdminPermissioned); ok && p != nil {
		return p.RequiredPermissions()
	}
	return nil
}

// WriteData writes a D-10 success envelope.
func WriteData(w http.ResponseWriter, status int, data, meta any) {
	if meta == nil {
		meta = map[string]any{}
	}
	writeJSON(w, status, map[string]any{"data": data, "meta": meta})
}

// WriteError writes a D-10 error envelope. details is always an object.
func WriteError(w http.ResponseWriter, status int, code, message string) {
	WriteErrorDetails(w, status, code, message, nil)
}

// WriteErrorDetails writes a D-10 error envelope with field messages.
func WriteErrorDetails(w http.ResponseWriter, status int, code, message string, details map[string]any) {
	if details == nil {
		details = map[string]any{}
	}
	writeJSON(w, status, map[string]any{
		"error": map[string]any{
			"code":    code,
			"message": message,
			"details": details,
		},
	})
}

// writeJSON encodes body before the status line goes out, so a value that
// cannot be encoded (NaN, an infinity, a failing MarshalJSON) is a logged 500
// with the generic body instead of a 200 with a truncated one.
func writeJSON(w http.ResponseWriter, status int, body any) {
	var buf bytes.Buffer
	if err := json.NewEncoder(&buf).Encode(body); err != nil {
		slog.Error("cabana: response could not be encoded", "status", status, "error", err)
		buf.Reset()
		_ = json.NewEncoder(&buf).Encode(map[string]any{
			"error": map[string]any{"code": "error", "message": msgServerError, "details": map[string]any{}},
		})
		status = http.StatusInternalServerError
	}
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_, _ = w.Write(buf.Bytes())
}