package controllers

import (
	"apiserver/common"
	"apiserver/models"
	"apiserver/store"
	"apiserver/utils"
	logger "apiserver/utils"
	"errors"
	"os"
	"sync"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gopkg.in/yaml.v2"
)

type RBACConfig struct {
	Permissions []string        `yaml:"permissions"`
	Roles       map[string]Role `yaml:"roles"`
	Users       map[string]User `yaml:"users"`
}

// define Role
type Role struct {
	Includes    []string     `yaml:"includes,omitempty"`
	Permissions []Permission `yaml:"permissions"`
}
type Permission struct {
	Action string   `yaml:"action"`
	Domain []Domain `yaml:"domain"`
}

// define User
type User struct {
	Roles []UserRole `yaml:"roles"`
}
type UserRole struct {
	Name   string   `yaml:"name"`
	Domain []Domain `yaml:"domain"`
}
type Domain struct {
	Type   string   `yaml:"type"`
	Values []string `yaml:"values,omitempty"`
}

var (
	rbacConfig RBACConfig
	once       sync.Once
)

func LoadRBACConfig(path string) error {
	logger.Debug("Enter LoadRBACConfig() function")
	data, err := os.ReadFile(path)
	if err != nil {
		return err
	}
	if err := yaml.Unmarshal(data, &rbacConfig); err != nil {
		return err
	}

	// Populate store.Roles from parsed config
	for roleName, role := range rbacConfig.Roles {
		var perms []store.RolePermission
		for _, perm := range role.Permissions {
			for _, domain := range perm.Domain {
				perms = append(perms, store.RolePermission{
					Action:       perm.Action,
					DomainType:   domain.Type,
					DomainValues: domain.Values,
				})
			}
		}
		store.AddRoleNames(roleName)
		if len(perms) > 0 {
			store.AddPermissionsForRole(roleName, perms)
		}
	}

	// Resolve role inheritance (includes)
	resolveRoleIncludes()

	// Load user-role mappings from users section
	for userName, user := range rbacConfig.Users {
		for _, role := range user.Roles {
			store.AddRoleForUser(userName, role.Name)
		}
	}

	return nil
}

func resolveRoleIncludes() {
	for roleName, rbacRole := range rbacConfig.Roles {
		if len(rbacRole.Includes) == 0 {
			continue
		}
		inherited := collectRolePermissions(
			UserRole{Name: roleName},
			rbacConfig.Roles,
			make(map[string]struct{}),
		)
		for _, perm := range inherited {
			for _, domain := range perm.Domain {
				store.AddPermissionsForRole(roleName, []store.RolePermission{
					{Action: perm.Action, DomainType: domain.Type, DomainValues: domain.Values},
				})
			}
		}
	}
}

// validate token and check permission
func RequirePermission(perm string) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		logger.Debug("Enter RequirePermission() function", zap.String("perm", perm))
		token := ctx.GetHeader("Authorization")
		logonUser, err := GetUsernameFromToken(token)
		if err != nil {
			ReturnError(ctx, common.ERROR_CODE, err.Error(), nil)
			return
		}
		logger.Debug("Logon user is ", zap.String("logonUser", logonUser))
		// check if user has cluster_admin role
		userRoles := store.GetUserRoleNames(logonUser)
		if utils.ContainsField(userRoles, "cluster_admin") {
			return
		}
		permsWithType := GetUserAllPermissionsWithType(logonUser)
		logger.Debug("In RequirePermission after call GetUserAllPermissionsWithType from cache",
			zap.Any("permsWithType", permsWithType))
		var allPerms []string
		for _, perm := range permsWithType {
			allPerms = append(allPerms, perm.Permission)
		}
		found := false
		for _, p := range allPerms {
			if p == perm {
				found = true
				ctx.Next()
				return
			}
		}
		if !found {
			logger.Error("Permission denied", zap.String("perm", perm), zap.String("logonUser", logonUser))
			ReturnError(ctx, common.ERROR_AUTH_CODE, common.ERROR_ACCESS_FORBIDDEN_MSG, nil)
			ctx.Abort()
			return
		}
	}
}

// get all permissions from rbac.yaml file
func GetAllPermissions() []string {
	permissions := rbacConfig.Permissions
	return permissions
}

// get role permissions
func GetBuiltinRolePermissions(roleName string) []Permission {
	role, ok := rbacConfig.Roles[roleName]
	if !ok {
		return []Permission{}
	}
	return role.Permissions
}

// get all user permission,
// if user not exist in store, use basic_user permission
func GetUserAllPermissionsWithType(userName string) []models.RolePermission {
	perms, fromRoles := collectUserPermissions(userName)
	if !fromRoles {
		return perms
	}
	permissionListsType := DeduplicatePermissions(perms)
	logger.Debug("case 4 DeduplicatePermissions", zap.Any("permissionListsType", permissionListsType))
	return permissionListsType
}

// collectUserPermissionsWithType returns every grant of the user, one entry
// per scope, before DeduplicatePermissions (bug-1934: job scopes add up).
func collectUserPermissionsWithType(userName string) []models.RolePermission {
	perms, _ := collectUserPermissions(userName)
	return perms
}

// collectUserPermissions returns the user's grants; fromRoles is false when
// the user has no roles and gets the builtin basic_user grants.
func collectUserPermissions(userName string) ([]models.RolePermission, bool) {
	userRoles := store.GetUserRoleNames(userName)
	if len(userRoles) == 0 {
		// case 1: user not in store, use basic_user
		builtInPerms := GetBuiltinRolePermissions("basic_user")
		permissionTransform := make([]models.RolePermission, 0)
		for _, p := range builtInPerms {
			for _, domain := range p.Domain {
				rp := models.RolePermission{
					Permission:   p.Action,
					DomainType:   domain.Type,
					DomainValues: domain.Values,
				}
				permissionTransform = append(permissionTransform, rp)
			}
		}
		logger.Debug("case 1, assign basic_user permission to unregistered user")
		return permissionTransform, false
	}

	builtInRoles := utils.IncludeBuiltinRoles(userRoles)
	var permissionListsType []models.RolePermission
	if len(builtInRoles) > 0 {
		permissionTransform := make([]models.RolePermission, 0)
		for _, role := range builtInRoles {
			builtinPerms := GetBuiltinRolePermissions(role)
			for _, p := range builtinPerms {
				for _, domain := range p.Domain {
					rp := models.RolePermission{
						Permission:   p.Action,
						DomainType:   domain.Type,
						DomainValues: domain.Values,
					}
					permissionTransform = append(permissionTransform, rp)
				}
			}
		}
		permissionListsType = append(permissionListsType, permissionTransform...)
		logger.Debug("case 2, builtin role permissions", zap.Any("permissionListsType", permissionListsType))
	}

	for _, userRole := range userRoles {
		permissionListsType = append(permissionListsType, GetRoleAllPermissionsWithType(userRole)...)
	}
	logger.Debug("case 3, before remove duplicated permissions", zap.Any("permissionListsType", permissionListsType))
	return permissionListsType, true
}

func GetRoleAllPermissionsWithType(roleName string) []models.RolePermission {
	var permissionsType []models.RolePermission
	perms := store.GetRolePermissions(roleName)
	for _, perm := range perms {
		permissionsType = append(permissionsType, models.RolePermission{
			Permission:   perm.Action,
			DomainType:   perm.DomainType,
			DomainValues: perm.DomainValues,
		})
	}
	return permissionsType
}

// DeduplicatePermissions removes duplicate permissions based on the specified rules:
// - If permission name and domain type are the same, keep only one
// - If domain values contain "all", keep the one without "all" when both exist
// DeduplicatePermissions removes duplicate permissions based on the specified rules:
// - If permission names are the same, keep only one
// - If one has specific domain values and another has "all" domain type, keep the specific one
func DeduplicatePermissions(permissions []models.RolePermission) []models.RolePermission {
	permissionMap := make(map[string]models.RolePermission) // key: permission_name
	for _, perm := range permissions {
		if existingPerm, exists := permissionMap[perm.Permission]; exists {
			// Check if one has more specific domain than the other
			existingHasAll := (existingPerm.DomainType == models.DomainTypeAll)
			currentHasAll := (perm.DomainType == models.DomainTypeAll)

			// If existing has "all" and current has specific domain, replace it
			if existingHasAll && !currentHasAll {
				permissionMap[perm.Permission] = perm
			} else if !existingHasAll && currentHasAll {
				// Keep existing specific domain, discard current "all"
				// No action needed
			} else if existingHasAll && currentHasAll {
				// Both have "all", keep existing
				// No action needed
			} else {
				// Both have specific domains, check if current has values and existing doesn't
				existingHasValues := len(existingPerm.DomainValues) > 0
				currentHasValues := len(perm.DomainValues) > 0

				if !existingHasValues && currentHasValues {
					permissionMap[perm.Permission] = perm
				} else if existingHasValues && !currentHasValues {
					// Keep existing with values
					// No action needed
				} else {
					// Both have values or both don't have values, merge or keep existing
					mergedValues := mergeDomainValues(existingPerm.DomainValues, perm.DomainValues)
					permissionMap[perm.Permission] = models.RolePermission{
						Permission:   existingPerm.Permission,
						DomainType:   existingPerm.DomainType,
						DomainValues: mergedValues,
					}
				}
			}
		} else {
			permissionMap[perm.Permission] = perm
		}
	}

	// Convert map back to slice
	result := make([]models.RolePermission, 0, len(permissionMap))
	for _, perm := range permissionMap {
		result = append(result, perm)
	}

	return result
}

// Helper function to check if domain values contain "all"
func hasAllDomain(domainValues []string) bool {
	for _, value := range domainValues {
		if value == models.DomainTypeAll {
			return true
		}
	}
	return false
}

func mergeDomainValues(values1, values2 []string) []string {
	// Use a map to track unique values
	valueMap := make(map[string]bool)

	// Add all values from first slice
	for _, v := range values1 {
		valueMap[v] = true
	}

	// Add all values from second slice
	for _, v := range values2 {
		valueMap[v] = true
	}

	// Convert back to slice
	merged := make([]string, 0, len(valueMap))
	for v := range valueMap {
		merged = append(merged, v)
	}

	return merged
}

func GetRequireResourcePermission(logonUser string, permId string) (models.RolePermission, error) {
	logger.Debug("Enter GetRequireResourcePermission() function",
		zap.Any("logonUser", logonUser), zap.Any("permId", permId))
	availablePerm := models.RolePermission{}

	perms := GetUserAllPermissionsWithType(logonUser)
	logger.Debug("In GetRequireResourcePermission function user permissions are:",
		zap.Any("perms", perms))
	if len(perms) == 0 {
		return availablePerm, errors.New("no permission")
	}

	for _, perm := range perms {
		if perm.Permission != permId {
			continue
		}
		availablePerm.Permission = perm.Permission
		availablePerm.DomainType = perm.DomainType
		availablePerm.DomainValues = perm.DomainValues
		return availablePerm, nil
	}

	return availablePerm, errors.New("no permission")
}
func collectRolePermissions(userRole UserRole, rbacRoles map[string]Role, visited map[string]struct{}) []Permission {
	var perms []Permission
	var collect func(roleName string, userDomains []Domain)
	collect = func(roleName string, userDomains []Domain) {
		if _, ok := visited[roleName]; ok {
			return
		}
		visited[roleName] = struct{}{}
		role, ok := rbacRoles[roleName]
		if !ok {
			return
		}
		for _, perm := range role.Permissions {
			mergedDomains := mergeDomains(perm.Domain, userDomains)
			if mergedDomains == nil {
				mergedDomains = []Domain{{Type: "all"}} // default to all if no
			}
			perms = append(perms, Permission{
				Action: perm.Action,
				Domain: mergedDomains,
			})
		}
		for _, inc := range role.Includes {
			collect(inc, userDomains)
		}
	}
	collect(userRole.Name, userRole.Domain)
	return perms
}
func mergeDomains(roleDomains, userDomains []Domain) []Domain {
	domainMap := make(map[string]map[string]struct{})
	if len(userDomains) == 1 && userDomains[0].Type == "all" {
		return roleDomains
	}
	if len(roleDomains) == 1 && roleDomains[0].Type == "all" {
		return userDomains
	}

	for _, d := range roleDomains {
		if d.Type == "all" {
			continue
		}
		if _, ok := domainMap[d.Type]; !ok {
			domainMap[d.Type] = make(map[string]struct{})
		}
		for _, v := range d.Values {
			domainMap[d.Type][v] = struct{}{}
		}
	}
	for _, d := range userDomains {
		if d.Type == "all" {
			continue
		}
		if _, ok := domainMap[d.Type]; !ok {
			domainMap[d.Type] = make(map[string]struct{})
		}
		for _, v := range d.Values {
			domainMap[d.Type][v] = struct{}{}
		}
	}
	var merged []Domain
	for t, vals := range domainMap {
		var values []string
		for v := range vals {
			values = append(values, v)
		}
		merged = append(merged, Domain{Type: t, Values: values})
	}
	return merged
}