import { $mobx, action, observable, runInAction, trace } from 'mobx';
import { computedFn } from 'mobx-utils';
import { ClientUtils, returnZero } from '../ClientUtils';
import { DocServer } from '../client/DocServer';
import { SerializationHelper } from '../client/util/SerializationHelper';
import { UndoManager } from '../client/util/UndoManager';
import { Doc, DocListCast, FieldType, FieldResult, HierarchyMapping, ReverseHierarchyMap, StrListCast, aclLevel, updateCachedAcls } from './Doc';
import { AclAdmin, AclAugment, AclEdit, AclPrivate, DirectLinks, DocAcl, DocData, DocLayout, FieldKeys, ForceServerWrite, Height, Initializing, SelfProxy, UpdatingFromServer, Width } from './DocSymbols';
import { FieldChanged, Id, Parent, ToValue } from './FieldSymbols';
import { List } from './List';
import { ObjectField } from './ObjectField';
import { PrefetchProxy, ProxyField } from './Proxy';
import { RefField } from './RefField';
import { RichTextField } from './RichTextField';
import { SchemaHeaderField } from './SchemaHeaderField';
import { ComputedField } from './ScriptField';
import { DocCast, ScriptCast, StrCast } from './Types';

/**
 * These are the various levels of access a user can have to a document.
 *
 * Admin: a user with admin access to a document can remove/edit that document, add/remove/edit annotations (depending on permissions), as well as change others' access rights to that document.
 * Edit: a user with edit access to a document can remove/edit that document, add/remove/edit annotations (depending on permissions), but not change any access rights to that document.
 * Add: a user with add access to a document can augment documents/annotations to that document but cannot edit or delete anything.
 * View: a user with view access to a document can only view it - they cannot add/remove/edit anything.
 * None: the document is not shared with that user.
 * Unset: Remove a sharing permission (eg., used )
 */
export enum SharingPermissions {
    Admin = 'Admin',
    Edit = 'Edit',
    Augment = 'Augment',
    View = 'View',
    None = 'Not-Shared',
}

function _readOnlySetter(): never {
    throw new Error("Documents can't be modified in read-only mode");
}

// eslint-disable-next-line prefer-const
let tracing = false;
export function TraceMobx() {
    tracing && trace();
}

export const _propSetterCB = new Map<string, ((target: any, value: any) => void) | undefined>();

const _setterImpl = action((target: any, prop: string | symbol | number, valueIn: any, receiver: any): boolean => {
    if (SerializationHelper.IsSerializing() || typeof prop === 'symbol') {
        target[prop] = valueIn;
        return true;
    }

    let value = valueIn?.[SelfProxy] ?? valueIn; // convert any Doc type values to Proxy's

    const curValue = target.__fieldTuples[prop];
    if (curValue === value || (curValue instanceof ProxyField && value instanceof RefField && curValue.fieldId === value[Id])) {
        // TODO This kind of checks correctly in the case that curValue is a ProxyField and value is a RefField, but technically
        // curValue should get filled in with value if it isn't already filled in, in case we fetched the referenced field some other way
        return true;
    }
    if (value instanceof RefField) {
        value = new ProxyField(value);
    }

    if (value instanceof ObjectField) {
        if (value[Parent] && value[Parent] !== receiver && !(value instanceof PrefetchProxy)) {
            throw new Error("Can't put the same object in multiple documents at the same time");
        }
        value[Parent] = receiver;
        // eslint-disable-next-line no-use-before-define
        value[FieldChanged] = containedFieldChangedHandler(receiver, prop, value);
    }
    if (curValue instanceof ObjectField) {
        delete curValue[Parent];
        delete curValue[FieldChanged];
    }

    if (typeof prop === 'string' && _propSetterCB.has(prop)) _propSetterCB.get(prop)!(target[SelfProxy], value);

    // eslint-disable-next-line no-use-before-define
    const effectiveAcl = GetEffectiveAcl(target);

    const writeMode = DocServer.getFieldWriteMode(prop as string);
    const fromServer = target[UpdatingFromServer];
    const sameAuthor = fromServer || receiver.author === ClientUtils.CurrentUserEmail();
    const writeToDoc =
        sameAuthor || effectiveAcl === AclEdit || effectiveAcl === AclAdmin || writeMode === DocServer.WriteMode.Playground || writeMode === DocServer.WriteMode.LivePlayground || (effectiveAcl === AclAugment && value instanceof RichTextField);
    const writeToServer =
        !DocServer.Control.isReadOnly() && //
        (sameAuthor || effectiveAcl === AclEdit || effectiveAcl === AclAdmin || (effectiveAcl === AclAugment && value instanceof RichTextField));

    if (writeToDoc) {
        if (value === undefined) {
            target[FieldKeys] && delete target[FieldKeys][prop]; // Lists don't have a FieldKeys field
            delete target.__fieldTuples[prop];
        } else {
            // bcz: uncomment to see if server is being updated
            // console.log(prop + ' = ' + value + '(' + curValue + ')');
            target[FieldKeys] && (target[FieldKeys][prop] = true); // Lists don't have a FieldKeys field
            target.__fieldTuples[prop] = value;
        }

        if (writeToServer) {
            // prettier-ignore
            if (value === undefined) 
                 (target as Doc|ObjectField)[FieldChanged]?.(undefined, { $unset: { ['fields.' + prop]: '' } });
            else (target as Doc|ObjectField)[FieldChanged]?.(undefined, { $set:   { ['fields.' + prop]: value instanceof ObjectField ? SerializationHelper.Serialize(value) :value}});
            if (prop === 'author' || prop.toString().startsWith('acl_')) updateCachedAcls(target);
        } else {
            DocServer.registerDocWithCachedUpdate(receiver, prop as string, curValue);
        }
        !receiver[Initializing] &&
            !StrListCast(receiver.undoIgnoreFields).includes(prop.toString()) &&
            (!receiver[UpdatingFromServer] || receiver[ForceServerWrite]) &&
            UndoManager.AddEvent(
                {
                    redo: () => {
                        receiver[prop] = value;
                    },
                    undo: () => {
                        const wasUpdate = receiver[UpdatingFromServer];
                        const wasForce = receiver[ForceServerWrite];
                        receiver[ForceServerWrite] = true; // needed since writes aren't propagated to server if UpdatingFromServerIsSet
                        receiver[UpdatingFromServer] = true; // needed if the event caused ACL's to change such that the doc is otherwise no longer editable.
                        receiver[prop] = curValue;
                        receiver[ForceServerWrite] = wasForce;
                        receiver[UpdatingFromServer] = wasUpdate;
                    },
                    prop: prop?.toString(),
                },
                value
            );
        return true;
    }
    return true;
});

let _setter: (target: any, prop: string | symbol | number, value: any, receiver: any) => boolean = _setterImpl;

export function makeReadOnly() {
    _setter = _readOnlySetter;
}

export function makeEditable() {
    _setter = _setterImpl;
}

export function normalizeEmail(email: string) {
    return email.replace(/\./g, '__');
}
export function denormalizeEmail(email: string) {
    return email.replace(/__/g, '.');
}

// return acl from cache or cache the acl and return.
// eslint-disable-next-line no-use-before-define
const getEffectiveAclCache = computedFn((target: any, user?: string) => getEffectiveAcl(target, user), true);

/**
 * Calculates the effective access right to a document for the current user.
 */
export function GetEffectiveAcl(target: any, user?: string): symbol {
    if (!target) return AclPrivate;
    if (target[UpdatingFromServer] || ClientUtils.CurrentUserEmail() === 'guest') return AclAdmin;
    return getEffectiveAclCache(target, user); // all changes received from the server must be processed as Admin.  return this directly so that the acls aren't cached (UpdatingFromServer is not observable)
}

export function GetPropAcl(target: any, prop: string | symbol | number) {
    if (typeof prop === 'symbol' || target[UpdatingFromServer]) return AclAdmin; // requesting the UpdatingFromServer prop or AclSym must always go through to keep the local DB consistent
    if (prop && DocServer.IsPlaygroundField(prop.toString())) return AclEdit; // playground props are always editable
    return GetEffectiveAcl(target);
}

const cachedGroups = observable([] as string[]);
const getCachedGroupByNameCache = computedFn((name: string) => cachedGroups.includes(name), true);

export function GetCachedGroupByName(name: string) {
    return getCachedGroupByNameCache(name);
}
export function SetCachedGroups(groups: string[]) {
    runInAction(() => cachedGroups.push(...groups));
}
function getEffectiveAcl(target: any, user?: string): symbol {
    const targetAcls = target[DocAcl];
    if (targetAcls?.acl_Me === AclAdmin || GetCachedGroupByName('Admin')) return AclAdmin;

    const userChecked = user || ClientUtils.CurrentUserEmail(); // if the current user is the author of the document / the current user is a member of the admin group
    if (targetAcls && Object.keys(targetAcls).length) {
        let effectiveAcl = AclPrivate;
        Object.entries(targetAcls).forEach(([key, value]) => {
            // there are issues with storing fields with . in the name, so they are replaced with _ during creation
            // as a result we need to restore them again during this comparison.
            const entity = denormalizeEmail(key.substring(4)); // an individual or a group
            if (GetCachedGroupByName(entity) || userChecked === entity || entity === 'Me') {
                if (HierarchyMapping.get(value as symbol)!.level > HierarchyMapping.get(effectiveAcl)!.level) {
                    effectiveAcl = value as symbol;
                }
            }
        });

        return DocServer?.Control?.isReadOnly?.() && HierarchyMapping.get(effectiveAcl)!.level < aclLevel.editable ? AclEdit : effectiveAcl;
    }
    // authored documents are private until an ACL is set.
    const targetAuthor = target.__fieldTuples?.author || target.author; // target may be a Doc of Proxy, so check __fieldTuples.author and .author
    if (targetAuthor && targetAuthor !== userChecked) return AclPrivate;
    return AclAdmin;
}

/**
 * Recursively distributes the access right for a user across the children of a document and its annotations.
 * @param key the key storing the access right (e.g. acl_groupname)
 * @param acl the access right being stored (e.g. "Can Edit")
 * @param target the document on which this access right is being set
 * @param visited list of Doc's already distributed to.
 * @param allowUpgrade whether permissions can be made less restrictive
 * @param layoutOnly just sets the layout doc's ACL (unless the data doc has no entry for the ACL, in which case it will be set as well)
 */
// eslint-disable-next-line default-param-last
export function distributeAcls(key: string, acl: SharingPermissions, target: Doc, visited: Doc[] = [], allowUpgrade?: boolean, layoutOnly = false) {
    const selfKey = `acl_${normalizeEmail(ClientUtils.CurrentUserEmail())}`;
    if (!target || visited.includes(target) || key === selfKey) return;
    visited.push(target);

    let dataDocChanged = false;
    const dataDoc = target[DocData];
    const curVal = ReverseHierarchyMap.get(StrCast(dataDoc[key]))?.level ?? 0;
    const aclVal = ReverseHierarchyMap.get(acl)?.level ?? 0;
    if (!layoutOnly && dataDoc && (allowUpgrade !== false || !dataDoc[key] || curVal > aclVal)) {
        // propagate ACLs to links, children, and annotations

        dataDoc[DirectLinks].forEach(link => distributeAcls(key, acl, link, visited, !!allowUpgrade));

        DocListCast(dataDoc[Doc.LayoutFieldKey(dataDoc)]).forEach(d => {
            distributeAcls(key, acl, d, visited, !!allowUpgrade);
            d !== d[DocData] && distributeAcls(key, acl, d[DocData], visited, !!allowUpgrade);
        });

        DocListCast(dataDoc[Doc.LayoutFieldKey(dataDoc) + '_annotations']).forEach(d => {
            distributeAcls(key, acl, d, visited, !!allowUpgrade);
            d !== d[DocData] && distributeAcls(key, acl, d[DocData], visited, !!allowUpgrade);
        });

        Object.keys(target) // share expanded layout templates (eg, for presElementBox'es )
            .filter(lkey => lkey.includes('layout[') && DocCast(target[lkey]))
            .forEach(lkey => distributeAcls(key, acl, DocCast(target[lkey]), visited, !!allowUpgrade));

        if (GetEffectiveAcl(dataDoc) === AclAdmin) {
            dataDoc[key] = acl;
            dataDocChanged = true;
        }
    }

    let layoutDocChanged = false; // determines whether fetchProto should be called or not (i.e. is there a change that should be reflected in target[AclSym])
    // if it is inheriting from a collection, it only inherits if A) allowUpgrade is set B) the key doesn't already exist or c) the right being inherited is more restrictive
    if (GetEffectiveAcl(target) === AclAdmin && (allowUpgrade || !Doc.GetT(target, key, 'boolean', true) || ReverseHierarchyMap.get(StrCast(target[key]))!.level > aclVal)) {
        target[key] = acl;
        layoutDocChanged = true;
        if (dataDoc[key] === undefined) dataDoc[key] = acl;
    }

    layoutDocChanged && updateCachedAcls(target); // updates target[AclSym] when changes to acls have been made
    dataDocChanged && updateCachedAcls(dataDoc);
}

/**
 * Copies parent's acl fields to the child
 */
export function inheritParentAcls(parent: Doc, child: Doc, layoutOnly: boolean) {
    [...Object.keys(parent), ...(ClientUtils.CurrentUserEmail() !== parent.author ? ['acl_Owner'] : [])]
        .filter(key => key.startsWith('acl_'))
        .forEach(key => {
            // if the default acl mode is private, then don't inherit the acl_guest permission, but set it to private.
            // const permission: string = key === 'acl_Guest' && Doc.defaultAclPrivate ? AclPrivate : parent[key];
            const parAcl = ReverseHierarchyMap.get(StrCast(key === 'acl_Owner' ? (Doc.defaultAclPrivate ? SharingPermissions.None : SharingPermissions.Edit) : parent[key]))?.acl;
            if (parAcl) {
                const sharePermission = HierarchyMapping.get(parAcl)?.name;
                sharePermission && distributeAcls(key === 'acl_Owner' ? `acl_${normalizeEmail(StrCast(parent.author))}` : key, sharePermission, child, undefined, false, layoutOnly);
            }
        });
}

/**
 * sets a callback function to be called whenever a value is assigned to the specified field key.
 * For example, this is used to "publish" documents with titles that start with '@'
 * @param prop
 * @param propSetter
 */
export function SetPropSetterCb(prop: string, propSetter: ((target: any, value: any) => void) | undefined) {
    _propSetterCB.set(prop, propSetter);
}

//
// target should be either a Doc or ListImpl.  receiver should be a Proxy<Doc> Or List.
//
export function setter(target: any, inProp: string | symbol | number, value: any, receiver: any): boolean {
    if (!inProp) {
        console.log('WARNING: trying to set an empty property.  This should be fixed. ');
        return false;
    }
    let prop = inProp;
    const effectiveAcl = inProp === 'constructor' || typeof inProp === 'symbol' ? AclAdmin : GetPropAcl(target, prop);
    if (effectiveAcl !== AclEdit && effectiveAcl !== AclAugment && effectiveAcl !== AclAdmin) return true;
    // if you're trying to change an acl but don't have Admin access / you're trying to change it to something that isn't an acceptable acl, you can't
    if (typeof prop === 'string' && prop.startsWith('acl_') && (effectiveAcl !== AclAdmin || ![...Object.values(SharingPermissions), undefined].includes(value))) return true;

    if (typeof prop === 'string' && prop !== '__id' && prop !== '__fieldTuples' && prop.startsWith('_')) {
        if (!prop.startsWith('__')) prop = prop.substring(1);
        if (target.__LAYOUT__) {
            target.__LAYOUT__[prop] = value;
            return true;
        }
    }
    if (target.__fieldTuples[prop] instanceof ComputedField) {
        if (target.__fieldTuples[prop].setterscript && value !== undefined && !(value instanceof ComputedField)) {
            return !!ScriptCast(target.__fieldTuples[prop])?.setterscript?.run({ self: target[SelfProxy], this: target[SelfProxy], value }).success;
        }
    }
    return _setter(target, prop, value, receiver);
}

function getFieldImpl(target: any, prop: string | number, proxy: any, ignoreProto: boolean = false): any {
    const field = target.__fieldTuples[prop];
    const value = field?.[ToValue]?.(proxy); // converts ComputedFields to values, or unpacks ProxyFields into Proxys
    if (value) return value.value;
    if (field === undefined && !ignoreProto && prop !== 'proto') {
        const proto = getFieldImpl(target, 'proto', proxy, true); // TODO tfs: instead of proxy we could use target[SelfProxy]... I don't which semantics we want or if it really matters
        if (proto instanceof Doc && GetEffectiveAcl(proto) !== AclPrivate) {
            return getFieldImpl(proto, prop, proxy, ignoreProto);
        }
    }
    return field;
}
export function getter(target: any, prop: string | symbol, proxy: any): any {
    // prettier-ignore
    switch (prop) {
        case 'then' :   return undefined;
        case 'constructor':   case 'toString': case 'valueOf':  
        case 'serializeInfo': case 'factory':     
                        return target[prop];
        case DocAcl :   return target[DocAcl];
        case $mobx:     return target.__fieldTuples[prop];
        case DocLayout: return target.__LAYOUT__;
        case Height: case Width: if (GetEffectiveAcl(target) === AclPrivate) return returnZero;
        // eslint-disable-next-line no-fallthrough
        default :
            if (typeof prop === 'symbol')  return target[prop];
            if (prop.startsWith('isMobX')) return target[prop];
            if (prop.startsWith('__'))     return target[prop];
            if (GetEffectiveAcl(target) === AclPrivate && prop !== 'author') return undefined;
    }

    const layoutProp = prop.startsWith('_') ? prop.substring(1) : undefined;
    if (layoutProp && target.__LAYOUT__) return target.__LAYOUT__[layoutProp];
    return getFieldImpl(target, layoutProp ?? prop, proxy);
}

export function getField(target: any, prop: string | number, ignoreProto: boolean = false): any {
    return getFieldImpl(target, prop, target[SelfProxy], ignoreProto);
}

export function deleteProperty(target: any, prop: string | number | symbol) {
    if (typeof prop === 'symbol') {
        delete target[prop];
    } else {
        target[SelfProxy][prop] = undefined;
    }
    return true;
}

// this function creates a function that can be used to setup Undo for whenever an ObjectField changes.
// the idea is that the Doc field setter can only setup undo at the granularity of an entire field and won't even be called if
// just a part of a field (eg. field within an ObjectField) changes.  This function returns a function that can be called
// whenever an internal ObjectField field changes. It should be passed a 'diff' specification describing the change. Currently,
// List's are the only true ObjectFields that can be partially modified (ignoring SchemaHeaderFields which should go away).
// The 'diff' specification that a list can send is limited to indicating that something was added, removed, or that the list contents
// were replaced.  Based on this specification, an Undo event is setup that will save enough information about the ObjectField to be
// able to undo and redo the partial change.
//
export function containedFieldChangedHandler(container: List<FieldType> | Doc, prop: string | number, liveContainedField: ObjectField) {
    let lastValue: FieldResult = liveContainedField instanceof ObjectField ? ObjectField.MakeCopy(liveContainedField) : liveContainedField;
    return (diff?: { op: '$addToSet' | '$remFromSet' | '$set'; items: FieldType[] | undefined; length: number | undefined; hint?: any } /* , dummyServerOp?: any */) => {
        const serializeItems = () => ({ __type: 'list', fields: diff?.items?.map((item: FieldType) => SerializationHelper.Serialize(item)) });
        // prettier-ignore
        const serverOp = diff?.op === '$addToSet'
            ? { $addToSet:   { ['fields.' + prop]: serializeItems() }, length: diff.length }
            : diff?.op === '$remFromSet'
            ? { $remFromSet: { ['fields.' + prop]: serializeItems(), hint: diff.hint}, length: diff.length }
            : { $set:        { ['fields.' + prop]: liveContainedField ? SerializationHelper.Serialize(liveContainedField) : undefined } };

        if (!(container instanceof Doc) || !container[UpdatingFromServer]) {
            const prevValue = ObjectField.MakeCopy(lastValue as List<any>);
            lastValue = ObjectField.MakeCopy(liveContainedField);
            const newValue = ObjectField.MakeCopy(liveContainedField);
            if (diff?.op === '$addToSet') {
                UndoManager.AddEvent(
                    {
                        redo: () => {
                            // console.log('redo $add: ' + prop, diff.items); // bcz: uncomment to log undo
                            (container as any)[prop as any]?.push(...((diff.items || [])?.map((item: any) => item.value ?? item) ?? []));
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        },
                        undo: action(() => {
                            // console.log('undo $add: ' + prop, diff.items); // bcz: uncomment to log undo
                            diff.items?.forEach((item: any) => {
                                const ind =
                                    item instanceof SchemaHeaderField //
                                        ? (container as any)[prop as any]?.findIndex((ele: any) => ele instanceof SchemaHeaderField && ele.heading === item.heading)
                                        : (container as any)[prop as any]?.indexOf(item.value ?? item);
                                ind !== undefined && ind !== -1 && (container as any)[prop as any]?.splice(ind, 1);
                            });
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        }),
                        prop: 'add ' + (diff.items?.length ?? 0) + ' items to list',
                    },
                    diff?.items
                );
            } else if (diff?.op === '$remFromSet') {
                UndoManager.AddEvent(
                    {
                        redo: action(() => {
                            // console.log('redo $rem: ' + prop, diff.items); // bcz: uncomment to log undo
                            diff.items?.forEach((item: any) => {
                                const ind =
                                    item instanceof SchemaHeaderField //
                                        ? (container as any)[prop as any]?.findIndex((ele: any) => ele instanceof SchemaHeaderField && ele.heading === item.heading)
                                        : (container as any)[prop as any]?.indexOf(item.value ?? item);
                                ind !== undefined && ind !== -1 && (container as any)[prop as any]?.splice(ind, 1);
                            });
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        }),
                        undo: () => {
                            // console.log('undo $rem: ' + prop, diff.items); // bcz: uncomment to log undo
                            diff.items?.forEach((item: any) => {
                                if (item instanceof SchemaHeaderField) {
                                    const ind = (prevValue as List<any>).findIndex((ele: any) => ele instanceof SchemaHeaderField && ele.heading === item.heading);
                                    ind !== -1 && (container as any)[prop as any].findIndex((ele: any) => ele instanceof SchemaHeaderField && ele.heading === item.heading) === -1 && (container as any)[prop as any].splice(ind, 0, item);
                                } else {
                                    const ind = (prevValue as List<any>).indexOf(item.value ?? item);
                                    ind !== -1 && (container as any)[prop as any].indexOf(item.value ?? item) === -1 && (container as any)[prop as any].splice(ind, 0, item);
                                }
                            });
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        },
                        prop: 'remove ' + (diff.items?.length ?? 0) + ' items from list(' + ((container as any)?.title ?? '') + ':' + prop + ')',
                    },
                    diff?.items
                );
            } else {
                const setFieldVal = (val: FieldType | undefined) => {
                    container instanceof Doc ? (container[prop as string] = val) : (container[prop as number] = val as FieldType);
                };
                UndoManager.AddEvent(
                    {
                        redo: () => {
                            // console.log('redo list: ' + prop, fieldVal()); // bcz: uncomment to log undo
                            setFieldVal(newValue instanceof ObjectField ? ObjectField.MakeCopy(newValue) : undefined);
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        },
                        undo: () => {
                            // console.log('undo list: ' + prop, fieldVal()); // bcz: uncomment to log undo
                            setFieldVal(prevValue instanceof ObjectField ? ObjectField.MakeCopy(prevValue) : undefined);
                            lastValue = ObjectField.MakeCopy((container as any)[prop as any]);
                        },
                        prop: 'set list field',
                    },
                    diff?.items
                );
            }
        }
        container[FieldChanged]?.(undefined, serverOp);
    };
}