/**
 * Utilities file for Panel Searches (panel/client search + advanced/backend search)
 * Note: Any mention of "DL" in this file refers to the Demerau-Levenshtein distance algorithm
 */
import {
    faFilter,
    faGraduationCap,
    faNewspaper,
    faProjectDiagram,
    faSitemap,
    faStar,
    faUndo,
    type IconDefinition,
} from "@fortawesome/free-solid-svg-icons";
import { orderBy } from "lodash";

import { isTool, isToolSection } from "@/api/tools";
import type {
    FilterSettings as ToolFilters,
    Tool,
    ToolPanelItem,
    ToolSection,
    ToolSectionLabel,
} from "@/stores/toolStore";
import levenshteinDistance from "@/utils/levenshtein";

export const FAVORITES_KEYS = ["#favs", "#favorites", "#favourites"];

/** Build a ToolSection object */
export function buildToolSection(id: string, name: string, tools: string[]): ToolSection {
    return {
        model_class: "ToolSection",
        id,
        name,
        tools,
    };
}

/** Build a ToolSectionLabel object */
export function buildToolLabel(id: string, text: string): ToolSectionLabel {
    return {
        model_class: "ToolSectionLabel",
        id,
        text,
    };
}

/** Build an array of [toolId, tool] entries from tool IDs and tools by ID map */
export function buildToolEntries(toolIds: string[], toolsById: Record<string, Tool>): Array<[string, Tool]> {
    return toolIds.map((id) => [id, toolsById[id]] as [string, Tool]).filter(([, tool]) => tool !== undefined);
}

/** Filter panel to only include tools matching the provided tool IDs */
export function filterPanelByToolIds(
    panel: Record<string, ToolPanelItem>,
    toolIds: Set<string>,
): Record<string, Tool | ToolSection> {
    const filtered: Record<string, Tool | ToolSection> = {};
    for (const [key, item] of Object.entries(panel)) {
        if ("tools" in item && item?.tools) {
            const tools = item.tools.filter((toolId) => typeof toolId === "string" && toolIds.has(toolId));
            if (tools.length > 0) {
                filtered[key] = { ...item, tools };
            }
        } else if (isTool(item) && toolIds.has(item.id)) {
            filtered[key] = item;
        }
    }
    return filtered;
}

const FILTER_KEYS = {
    id: ["id", "tool_id"],
    panel_section_name: ["section", "panel_section_name"],
    labels: ["label", "labels", "tag"],
};
const STRING_REPLACEMENTS: string[] = [" ", "-", "\\(", "\\)", "'", ":", `"`];
const MINIMUM_DL_LENGTH = 5; // for Demerau-Levenshtein distance
const MINIMUM_WORD_MATCH = 2; // for word match
export const UNSECTIONED_SECTION: ToolSection = {
    // to return a section for unsectioned tools
    model_class: "ToolSection",
    id: "unsectioned",
    name: "Unsectioned Tools",
    description: "Tools that don't appear under any section in the unsearched panel",
} as const;

export interface SearchCommonKeys {
    [key: string]: number | undefined;
    /** The `name` key must exist on the objects */
    name?: number;
    /** property has exact match with query */
    exact?: number;
    /** property starts with query */
    startsWith?: number;
    /** query contains matches of combined keys (e.g.: `Tool.name + Tool.description`) */
    combined?: number;
    /** e.g.: `Tool.name + Tool.description` contains at least
     * `MINIMUM_WORD_MATCH` words from query
     */
    wordMatch?: number;
}

interface SearchMatch {
    id: string;
    /** The order of the match, higher number = higher rank in results */
    order: number;
}

const TOOL_SEARCH_KEYS: SearchCommonKeys = {
    exact: 5,
    startsWith: 4,
    name: 3,
    description: 2,
    combined: 1,
    wordMatch: 0,
};
const TOOL_SECTION_SEARCH_KEYS: SearchCommonKeys = { exact: 4, startsWith: 3, name: 2, wordMatch: 1, description: 0 };

/** Returns icon for tool panel `view_type` */
export const types_to_icons = {
    default: faUndo,
    favorites: faStar,
    generic: faFilter,
    ontology: faSitemap,
    activity: faProjectDiagram,
    publication: faNewspaper,
    training: faGraduationCap,
} as const satisfies Record<string, IconDefinition>;

// Converts filterSettings { key: value } to query = "key:value"
export function createWorkflowQuery(filterSettings: Record<string, string | boolean>) {
    let query = "";
    query = Object.entries(filterSettings)
        .filter(([, value]) => value)
        .map(([filter, value]) => {
            if (value === true) {
                return `is:${filter}`;
            }
            return `${filter}:${value}`;
        })
        .join(" ");
    if (Object.keys(filterSettings).length == 1 && filterSettings.name) {
        return filterSettings.name as string;
    }
    return query;
}

/** Converts filters into tool search backend whoosh query.
 * @param filterSettings e.g.: {"name": "Tool Name", "section": "Collection", ...}
 * @returns parsed Whoosh `query`
 * @example
 *      createWhooshQuery(filterSettings = {"name": "skew", "ontology": "topic_0797"})
 *      return query = "(name:(skew) name_exact:(skew) description:(skew)) AND (edam_topics:(topic_0797) AND )"
 */
export function createWhooshQuery(filterSettings: ToolFilters) {
    let query = "(";
    // add description+name_exact fields = name, to do a combined OrGroup at backend
    const name = filterSettings["name"];
    if (name) {
        query += "name:(" + name + ") ";
        query += "name_exact:(" + name + ") ";
        query += "description:(" + name + ")";
    }
    query += ") AND (";
    for (const [key, filterValue] of Object.entries(filterSettings)) {
        if (filterValue) {
            if (key === "ontology" && filterValue.includes("operation")) {
                query += "edam_operations:(" + filterValue + ") AND ";
            } else if (key === "ontology" && filterValue.includes("topic")) {
                query += "edam_topics:(" + filterValue + ") AND ";
            } else if (key == "id") {
                query += "id_exact:(" + filterValue + ") AND ";
            } else if (key != "name") {
                query += key + ":(" + filterValue + ") AND ";
            }
        }
    }
    query += ")";
    return query;
}

// Determines width given the root and draggable element, smallest and largest size and the current position
export function determineWidth(
    rectRoot: { left: number; right: number },
    rectDraggable: { left: number },
    minWidth: number,
    maxWidth: number,
    direction: string,
    positionX: number,
) {
    let newWidth = null;
    if (direction === "right") {
        const offset = rectRoot.left - rectDraggable.left;
        newWidth = rectRoot.right - positionX - offset;
    } else {
        const offset = rectRoot.right - rectDraggable.left;
        newWidth = positionX - rectRoot.left + offset;
    }
    return Math.max(minWidth, Math.min(maxWidth, newWidth));
}

/**
 * @param toolsById - all tools, keyed by id
 * @param results - list of result tool ids
 * @returns filtered tool results (by id)
 */
export function filterTools(toolsById: Record<string, Tool>, results: string[]) {
    const filteredTools: Record<string, Tool> = {};
    for (const id of results) {
        const localTool = toolsById[id];
        if (localTool !== undefined) {
            filteredTools[id] = localTool;
        }
    }
    return filteredTools;
}

/** Returns a `toolsById` object containing tools that meet required conditions such as:
 * - Not `hidden`
 * - Not `disabled`
 * - If in workflow editor panel, only tools that are `is_workflow_compatible`
 * - Not in an excluded section (if `excludedSectionIds` provided)
 * @param toolsById object of tools, keyed by id
 * @param isWorkflowPanel whether or not the ToolPanel is in Workflow Editor
 * @param excludedSectionIds ids for sections whose tools will be excluded
 */
export function getVisibleTools(
    toolsById: Record<string, Tool>,
    isWorkflowPanel = false,
    excludedSectionIds: string[] = [],
) {
    const excludeSet = new Set(excludedSectionIds);
    const validTools: Record<string, Tool> = {};

    for (const [toolId, tool] of Object.entries(toolsById)) {
        const { panel_section_id, hidden, disabled, is_workflow_compatible } = tool;
        if (
            !excludeSet.has(panel_section_id) &&
            !hidden &&
            disabled !== true &&
            !(isWorkflowPanel && !is_workflow_compatible)
        ) {
            validTools[toolId] = tool;
        }
    }

    return validTools;
}

/** Looks in each section of `currentPanel` and filters `section.tools` on `validToolIdsInCurrentView` */
export function getValidToolsInEachSection(
    validToolIdsInCurrentView: Set<string>,
    currentPanel: Record<string, ToolPanelItem>,
): Array<[string, ToolPanelItem]> {
    return Object.entries(currentPanel).map(([id, section]) => {
        if (isToolSection(section)) {
            const validatedSection = { ...section };
            // assign sectionTools to avoid repeated getter access
            const sectionTools = validatedSection.tools;
            if (sectionTools && Array.isArray(sectionTools)) {
                // filter on valid tools and panel labels in this section
                validatedSection.tools = sectionTools.filter((toolId) => {
                    if (typeof toolId === "string" && validToolIdsInCurrentView.has(toolId)) {
                        return true;
                    } else if (typeof toolId !== "string") {
                        // is a special case where there is a label within a section
                        return true;
                    }
                });
            }
            return [id, validatedSection];
        }
        return [id, section];
    });
}

/**
 * @param items - `[id, PanelItem]` entries (from the `currentPanel` object)
 * @param validToolIdsInCurrentView - tool ids that are valid in current view
 * @param excludedSectionIds - any section ids to exclude
 * @returns a `currentPanel` object containing sections/tools/labels that meet required conditions
 */
export function getValidPanelItems(
    items: Array<[string, ToolPanelItem]>,
    validToolIdsInCurrentView: Set<string>,
    excludedSectionIds: string[] = [],
) {
    const validEntries = items.filter(([id, item]) => {
        if (isTool(item) && validToolIdsInCurrentView.has(id)) {
            // is a `Tool` and is in `localToolsById`
            return true;
        } else if (!isToolSection(item)) {
            // is neither a `Tool` nor a `ToolSection`, maybe a `ToolSectionLabel`
            return true;
        } else if ("tools" in item && item.tools?.length && !excludedSectionIds.includes(id)) {
            // is a `ToolSection` with tools; is not an excluded section
            return true;
        } else {
            return false;
        }
    });
    return Object.fromEntries(validEntries);
}

/**
 * Given toolbox, keys to sort/search results by and a search query,
 * Does a direct string.match() comparison to find results,
 * If that produces nothing, runs Damerau-Levenshtein distance algorithm to allow misspells
 *
 * @param tools - toolbox
 * @param query - a search query
 * @param currentPanel - current ToolPanel with { section_id: { tools: [tool ids] }, ... }
 * @returns an object containing
 * - results: array of tool ids that match the query
 * - resultPanel: a ToolPanel with only the results for the currentPanel
 * - closestTerm: Optional: closest matching term for DL (in case no match with query)
 *
 * all sorted by order of keys that are being searched (+ closest matching term if DL)
 */
export function searchTools(
    tools: Tool[],
    query: string,
    currentPanel: Record<string, ToolPanelItem>,
): {
    results: string[];
    resultPanel: Record<string, Tool | ToolSection>;
    closestTerm: string | null;
} {
    const { matchedResults, closestTerm } = searchObjectsByKeys<Tool>(tools, TOOL_SEARCH_KEYS, query, [
        "name",
        "description",
    ]);
    const { idResults, resultPanel } = createSortedResultPanel(matchedResults, currentPanel);
    return { results: idResults, resultPanel: resultPanel, closestTerm: closestTerm };
}

export function searchSections(sections: ToolSection[], query: string) {
    const sectionsById = sections.reduce(
        (acc, section) => {
            acc[section.id] = section;
            return acc;
        },
        {} as Record<string, ToolSection>,
    );

    const { matchedResults, closestTerm } = searchObjectsByKeys<ToolSection>(sections, TOOL_SECTION_SEARCH_KEYS, query);

    const filteredSectionEntries = orderBy(matchedResults, ["order"], ["desc"])
        .map((match) => sectionsById[match.id])
        .filter((section) => section !== undefined);

    return { sections: filteredSectionEntries, closestTerm };
}

/**
 * Given an array of typed objects, searches for matches based on specified keys and a query.
 *
 * @param objects Array of objects to search through
 * @param keys Keys of the object to search by (and some other special keys), ordered by result priority
 * @param query The search query _(will be sanitized in this method)_
 * @param nameKeys Keys to use for name matching and DL algorithm _(values for keys will be concatenated if a `combined` key is provided)_
 * @param usesDL Boolean used for a recursive call with Damerau-Levenshtein distance check activated
 * @returns An object containing results with sort order, as well as a _"Did you mean?"_ `closestTerm`
 */
export function searchObjectsByKeys<T extends { id: string }>(
    objects: T[],
    keys: SearchCommonKeys,
    query: string,
    nameKeys: string[] = ["name"],
    usesDL = false,
): {
    /** An object containing the ids and sort `order` of each result.
     * @example [{ id: "tool1", order: 1 }, { id: "tool2", order: 2 }]
     */
    matchedResults: SearchMatch[];
    closestTerm: string | null;
} {
    const matchedResults: SearchMatch[] = [];
    let closestTerm = null;

    // check if query is of the form "property:value" and then ONLY filter on that property
    const { filteredQuery, filteredKeys } = filterOnKeys(query, FILTER_KEYS);
    if (filteredQuery) {
        query = filteredQuery;
        keys = filteredKeys;
    }

    const queryWords = query.trim().toLowerCase().split(" ");
    const queryValue = sanitizeString(query.trim().toLowerCase(), STRING_REPLACEMENTS);
    for (const searchedObj of objects) {
        for (const key of Object.keys(keys)) {
            if (searchedObj[key as keyof T] || key === "combined") {
                let actualValue = "";
                // key = "combined" is a special case (e.g.: for searching name + description)
                if (key === "combined" && nameKeys.length > 1) {
                    actualValue = nameKeys
                        .map((k) => searchedObj[k as keyof T])
                        .join(" ")
                        .trim()
                        .toLowerCase();
                } else {
                    const valAtKey = searchedObj[key as keyof T];
                    if (typeof valAtKey === "string") {
                        actualValue = valAtKey.trim().toLowerCase();
                    } else if (Array.isArray(valAtKey)) {
                        actualValue = valAtKey.join(" ").trim().toLowerCase();
                    } else if (typeof valAtKey === "number") {
                        actualValue = valAtKey.toString().trim().toLowerCase();
                    }
                }

                // get all (space separated) words in actualValue for searchedObj (for DL)
                const actualValueWords = actualValue.split(" ");
                actualValue = sanitizeString(actualValue, STRING_REPLACEMENTS);

                // do we care for exact matches && is it an exact match ?
                let order =
                    keys.exact !== undefined && actualValue === queryValue
                        ? (keys.exact as number)
                        : (keys[key] as number);
                // do we care for startsWith && does it actualValue start with query ?
                order =
                    keys.startsWith !== undefined &&
                    order !== keys.exact &&
                    key === "name" &&
                    actualValue.startsWith(queryValue)
                        ? keys.startsWith
                        : order;

                const wordMatches = Array.from(new Set(actualValueWords.filter((word) => queryWords.includes(word))));
                if (!usesDL) {
                    if (actualValue.match(queryValue)) {
                        // if string.match() returns true, matching searchedObj found
                        matchedResults.push({ id: searchedObj.id, order });
                        break;
                    } else if (
                        key === "combined" &&
                        keys.wordMatch !== undefined &&
                        wordMatches.length >= MINIMUM_WORD_MATCH
                    ) {
                        // we are looking at combined name+description, and there are enough word matches
                        matchedResults.push({ id: searchedObj.id, order: keys.wordMatch });
                        break;
                    }
                } else if (usesDL) {
                    // if string.match() returns false, try DL distance once to see if there is a closestSubstring
                    let substring = null;
                    if (nameKeys.includes(key) && queryValue.length >= MINIMUM_DL_LENGTH) {
                        substring = closestSubstring(queryValue, actualValue);
                    }
                    // there is a closestSubstring: matching searchedObj found
                    if (substring) {
                        // get the closest matching term for substring
                        const foundTerm = matchingTerm(actualValueWords, substring);
                        if (foundTerm && (!closestTerm || (closestTerm && foundTerm.length < closestTerm.length))) {
                            closestTerm = foundTerm;
                        }
                        matchedResults.push({ id: searchedObj.id, order });
                        break;
                    }
                }
            }
        }
    }
    // no results with string.match(): recursive call with usesDL
    if (!filteredQuery && !usesDL && matchedResults.length == 0) {
        return searchObjectsByKeys(objects, keys, query, nameKeys, true);
    }
    return {
        matchedResults,
        closestTerm,
    };
}

function getOrCreateSection(
    acc: Record<string, Tool | ToolSection>,
    sectionId: string,
    sectionName: string,
): ToolSection {
    return acc[sectionId] && isToolSection(acc[sectionId])
        ? (acc[sectionId] as ToolSection)
        : buildToolSection(sectionId, sectionName, []);
}

function addToolToSection(
    acc: Record<string, Tool | ToolSection>,
    sectionId: string,
    sectionName: string,
    toolId: string,
): boolean {
    const section = getOrCreateSection(acc, sectionId, sectionName);
    section.tools?.push(toolId);
    acc[sectionId] = section;
    return true;
}

/**
 * Orders the matchedTools by order of keys that are being searched, and creates a resultPanel
 * @param matchedTools containing { id: tool id, order: order }
 * @param currentPanel current ToolPanel for current view
 * @returns an object containing
 * - idResults: array of tool ids that match the query
 * - resultPanel: a ToolPanel with only the results
 */
export function createSortedResultPanel(matchedTools: SearchMatch[], currentPanel: Record<string, ToolPanelItem>) {
    const idResults: string[] = [];

    // creating a sectioned results object ({section_id: [tool ids], ...}), keeping
    // track unique ids of each tool, and also sorting by indexed order of keys
    const resultPanel = orderBy(matchedTools, ["order"], ["desc"]).reduce(
        (acc: Record<string, Tool | ToolSection>, match: SearchMatch) => {
            // we need to search all sections in panel for this tool id
            const panelItems = Object.keys(currentPanel);
            for (const itemId of panelItems) {
                const existingPanelItem = currentPanel[itemId];
                if (!existingPanelItem) {
                    continue;
                }

                let toolAdded = false;

                if ("tools" in existingPanelItem && existingPanelItem.tools?.includes(match.id)) {
                    // it has tools so is a section, and it has the tool we're looking for
                    toolAdded = addToolToSection(acc, itemId, existingPanelItem.name, match.id);
                } else if (isTool(existingPanelItem) && existingPanelItem.id === match.id) {
                    // it is a tool, and it is the tool we're looking for
                    // put it in the "Unsectioned Tools" section
                    toolAdded = addToolToSection(acc, UNSECTIONED_SECTION.id, UNSECTIONED_SECTION.name, match.id);
                }

                if (toolAdded && !idResults.includes(match.id)) {
                    idResults.push(match.id);
                }
            }
            return acc;
        },
        {},
    );
    return { idResults, resultPanel };
}

/**
 *
 * @param query
 * @param actualStr
 * @returns substring with smallest DL distance, or null
 */
function closestSubstring(query: string, actualStr: string) {
    // Create max distance
    // Max distance a query and substring can be apart
    const maxDistance = Math.floor(query.length / 5);
    // Create an array of all actualStr substrings that are query length, query length -1, and query length + 1
    const substrings = Array.from({ length: actualStr.length - query.length + maxDistance }, (_, i) =>
        actualStr.substr(i, query.length),
    );
    if (query.length > 1) {
        substrings.push(
            ...Array.from({ length: actualStr.length - query.length + maxDistance + 1 }, (_, i) =>
                actualStr.substr(i, query.length - maxDistance),
            ),
        );
    }
    if (actualStr.length > query.length) {
        substrings.push(
            ...Array.from({ length: actualStr.length - query.length }, (_, i) =>
                actualStr.substr(i, query.length + maxDistance),
            ),
        );
    }
    // check to see if any substrings have a levenshtein distance less than the max distance
    for (const substring of substrings) {
        if (levenshteinDistance(query, substring, true) <= maxDistance) {
            return substring;
        }
    }
    return null;
}

// given array and a substring, get the closest matching term for substring
function matchingTerm(termArray: string[], substring: string) {
    const sanitized = sanitizeString(substring);

    for (const i in termArray) {
        const term = termArray[i];
        if (term?.match(sanitized)) {
            return term;
        }
    }
    return null;
}

/**
 *
 * @param value - to be sanitized
 * @param targets - Optional: characters to replace
 * @param substitute - Optional: replacement character
 * @returns sanitized string
 */
function sanitizeString(value: string, targets: string[] = [], substitute = "") {
    let sanitized = value;
    targets.forEach((rep) => {
        sanitized = sanitized.replace(new RegExp(rep, "g"), substitute);
    });

    return sanitized.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}

/**
 * If the query is of the form "property:value", return the value and keys which
 * ONLY filter on that property.
 * Otherwise, return null/empty object.
 * @param query - the raw query
 * @param keys - keys to filter for
 */
function filterOnKeys(query: string, keys: Record<string, string[]>) {
    for (const key in keys) {
        const filteredQuery = processForProperty(query, keys[key] || []);
        if (filteredQuery) {
            return { filteredQuery, filteredKeys: { [key]: 1 } };
        }
    }
    return { filteredQuery: null, filteredKeys: {} };
}

/**
 * If the query is of the form "property:value", return the value.
 * Otherwise, return null.
 * @param query - the raw query
 * @param keys - keys to check for
 * @returns value or null
 */
function processForProperty(query: string, keys: string[]) {
    for (const key of keys) {
        if (query.trim().startsWith(`${key}:`)) {
            return query.split(`${key}:`)[1]?.trim();
        }
    }
    return null;
}