'use server';

import { env } from "@/env.mjs";
import { invalidZoektResponse, ServiceError } from "../../lib/serviceError";
import { isServiceError } from "../../lib/utils";
import { zoektFetch } from "./zoektClient";
import { ErrorCode } from "../../lib/errorCodes";
import { StatusCodes } from "http-status-codes";
import { zoektSearchResponseSchema } from "./zoektSchema";
import { SearchRequest, SearchResponse, SourceRange } from "./types";
import { PrismaClient, Repo } from "@sourcebot/db";
import { sew } from "@/actions";
import { base64Decode } from "@sourcebot/shared";
import { withOptionalAuthV2 } from "@/withAuthV2";

// List of supported query prefixes in zoekt.
// @see : https://github.com/sourcebot-dev/zoekt/blob/main/query/parse.go#L417
enum zoektPrefixes {
    archived = "archived:",
    branchShort = "b:",
    branch = "branch:",
    caseShort = "c:",
    case = "case:",
    content = "content:",
    fileShort = "f:",
    file = "file:",
    fork = "fork:",
    public = "public:",
    repoShort = "r:",
    repo = "repo:",
    regex = "regex:",
    lang = "lang:",
    sym = "sym:",
    typeShort = "t:",
    type = "type:",
    reposet = "reposet:",
}

const transformZoektQuery = async (query: string, orgId: number, prisma: PrismaClient): Promise<string | ServiceError> => {
    const prevQueryParts = query.split(" ");
    const newQueryParts = [];

    for (const part of prevQueryParts) {

        // Handle mapping `rev:` and `revision:` to `branch:`
        if (part.match(/^-?(rev|revision):.+$/)) {
            const isNegated = part.startsWith("-");
            let revisionName = part.slice(part.indexOf(":") + 1);

            // Special case: `*` -> search all revisions.
            // In zoekt, providing a blank string will match all branches.
            // @see: https://github.com/sourcebot-dev/zoekt/blob/main/eval.go#L560-L562
            if (revisionName === "*") {
                revisionName = "";
            }
            newQueryParts.push(`${isNegated ? "-" : ""}${zoektPrefixes.branch}${revisionName}`);
        }

        // Expand `context:` into `reposet:` atom.
        else if (part.match(/^-?context:.+$/)) {
            const isNegated = part.startsWith("-");
            const contextName = part.slice(part.indexOf(":") + 1);

            const context = await prisma.searchContext.findUnique({
                where: {
                    name_orgId: {
                        name: contextName,
                        orgId,
                    }
                },
                include: {
                    repos: true,
                }
            });

            // If the context doesn't exist, return an error.
            if (!context) {
                return {
                    errorCode: ErrorCode.SEARCH_CONTEXT_NOT_FOUND,
                    message: `Search context "${contextName}" not found`,
                    statusCode: StatusCodes.NOT_FOUND,
                } satisfies ServiceError;
            }

            const names = context.repos.map((repo) => repo.name);
            newQueryParts.push(`${isNegated ? "-" : ""}${zoektPrefixes.reposet}${names.join(",")}`);
        }

        // no-op: add the original part to the new query parts.
        else {
            newQueryParts.push(part);
        }
    }

    return newQueryParts.join(" ");
}

// Extracts a repository file URL from a zoekt template, branch, and file name.
const getFileWebUrl = (template: string, branch: string, fileName: string): string | undefined => {
    // This is a hacky parser for templates generated by
    // the go text/template package. Example template:
    // {{URLJoinPath "https://github.com/sourcebot-dev/sourcebot" "blob" .Version .Path}}

    if (!template.match(/^{{URLJoinPath\s.*}}(\?.+)?$/)) {
        return undefined;
    }

    const url =
        template.substring("{{URLJoinPath ".length, template.indexOf("}}"))
            .split(" ")
            .map((part) => {
                // remove wrapping quotes
                if (part.startsWith("\"")) part = part.substring(1);
                if (part.endsWith("\"")) part = part.substring(0, part.length - 1);
                // Replace variable references
                if (part == ".Version") part = branch;
                if (part == ".Path") part = fileName;
                return part;
            })
            .join("/");

    const optionalQueryParams =
        template.substring(template.indexOf("}}") + 2)
            .replace("{{.Version}}", branch)
            .replace("{{.Path}}", fileName);

    return encodeURI(url + optionalQueryParams);
}

export const search = async ({ query, matches, contextLines, whole }: SearchRequest) => sew(() =>
    withOptionalAuthV2(async ({ org, prisma }) => {
        const transformedQuery = await transformZoektQuery(query, org.id, prisma);
        if (isServiceError(transformedQuery)) {
            return transformedQuery;
        }
        query = transformedQuery;

        const isBranchFilteringEnabled = (
            query.includes(zoektPrefixes.branch) ||
            query.includes(zoektPrefixes.branchShort)
        );

        // We only want to show matches for the default branch when
        // the user isn't explicitly filtering by branch.
        if (!isBranchFilteringEnabled) {
            query = query.concat(` branch:HEAD`);
        }

        const body = JSON.stringify({
            q: query,
            // @see: https://github.com/sourcebot-dev/zoekt/blob/main/api.go#L892
            opts: {
                ChunkMatches: true,
                MaxMatchDisplayCount: matches,
                NumContextLines: contextLines,
                Whole: !!whole,
                TotalMaxMatchCount: env.TOTAL_MAX_MATCH_COUNT,
                ShardMaxMatchCount: env.SHARD_MAX_MATCH_COUNT,
                MaxWallTime: env.ZOEKT_MAX_WALL_TIME_MS * 1000 * 1000, // zoekt expects a duration in nanoseconds
            }
        });

        let header: Record<string, string> = {};
        header = {
            "X-Tenant-ID": org.id.toString()
        };

        const searchResponse = await zoektFetch({
            path: "/api/search",
            body,
            header,
            method: "POST",
        });

        if (!searchResponse.ok) {
            return invalidZoektResponse(searchResponse);
        }

        const searchBody = await searchResponse.json();

        const parser = zoektSearchResponseSchema.transform(async ({ Result }) => {
            // @note (2025-05-12): in zoekt, repositories are identified by the `RepositoryID` field
            // which corresponds to the `id` in the Repo table. In order to efficiently fetch repository
            // metadata when transforming (potentially thousands) of file matches, we aggregate a unique
            // set of repository ids* and map them to their corresponding Repo record.
            //
            // *Q: Why is `RepositoryID` optional? And why are we falling back to `Repository`?
            //  A: Prior to this change, the repository id was not plumbed into zoekt, so RepositoryID was
            // always undefined. To make this a non-breaking change, we fallback to using the repository's name
            // (`Repository`) as the identifier in these cases. This is not guaranteed to be unique, but in
            // practice it is since the repository name includes the host and path (e.g., 'github.com/org/repo',
            // 'gitea.com/org/repo', etc.).
            // 
            // Note: When a repository is re-indexed (every hour) this ID will be populated.
            // @see: https://github.com/sourcebot-dev/zoekt/pull/6
            const repoIdentifiers = new Set(Result.Files?.map((file) => file.RepositoryID ?? file.Repository) ?? []);
            const repos = new Map<string | number, Repo>();

            (await prisma.repo.findMany({
                where: {
                    id: {
                        in: Array.from(repoIdentifiers).filter((id) => typeof id === "number"),
                    },
                    orgId: org.id,
                }
            })).forEach(repo => repos.set(repo.id, repo));

            (await prisma.repo.findMany({
                where: {
                    name: {
                        in: Array.from(repoIdentifiers).filter((id) => typeof id === "string"),
                    },
                    orgId: org.id,
                }
            })).forEach(repo => repos.set(repo.name, repo));

            const files = Result.Files?.map((file) => {
                const fileNameChunks = file.ChunkMatches.filter((chunk) => chunk.FileName);

                const webUrl = (() => {
                    const template: string | undefined = Result.RepoURLs[file.Repository];
                    if (!template) {
                        return undefined;
                    }

                    // If there are multiple branches pointing to the same revision of this file, it doesn't
                    // matter which branch we use here, so use the first one.
                    const branch = file.Branches && file.Branches.length > 0 ? file.Branches[0] : "HEAD";
                    return getFileWebUrl(template, branch, file.FileName);
                })();

                const identifier = file.RepositoryID ?? file.Repository;
                const repo = repos.get(identifier);

                // This can happen if the user doesn't have access to the repository.
                if (!repo) {
                    return undefined;
                }

                return {
                    fileName: {
                        text: file.FileName,
                        matchRanges: fileNameChunks.length === 1 ? fileNameChunks[0].Ranges.map((range) => ({
                            start: {
                                byteOffset: range.Start.ByteOffset,
                                column: range.Start.Column,
                                lineNumber: range.Start.LineNumber,
                            },
                            end: {
                                byteOffset: range.End.ByteOffset,
                                column: range.End.Column,
                                lineNumber: range.End.LineNumber,
                            }
                        })) : [],
                    },
                    repository: repo.name,
                    repositoryId: repo.id,
                    webUrl: webUrl,
                    language: file.Language,
                    chunks: file.ChunkMatches
                        .filter((chunk) => !chunk.FileName) // Filter out filename chunks.
                        .map((chunk) => {
                            return {
                                content: base64Decode(chunk.Content),
                                matchRanges: chunk.Ranges.map((range) => ({
                                    start: {
                                        byteOffset: range.Start.ByteOffset,
                                        column: range.Start.Column,
                                        lineNumber: range.Start.LineNumber,
                                    },
                                    end: {
                                        byteOffset: range.End.ByteOffset,
                                        column: range.End.Column,
                                        lineNumber: range.End.LineNumber,
                                    }
                                }) satisfies SourceRange),
                                contentStart: {
                                    byteOffset: chunk.ContentStart.ByteOffset,
                                    column: chunk.ContentStart.Column,
                                    lineNumber: chunk.ContentStart.LineNumber,
                                },
                                symbols: chunk.SymbolInfo?.map((symbol) => {
                                    return {
                                        symbol: symbol.Sym,
                                        kind: symbol.Kind,
                                        parent: symbol.Parent.length > 0 ? {
                                            symbol: symbol.Parent,
                                            kind: symbol.ParentKind,
                                        } : undefined,
                                    }
                                }) ?? undefined,
                            }
                        }),
                    branches: file.Branches,
                    content: file.Content ? base64Decode(file.Content) : undefined,
                }
            }).filter((file) => file !== undefined) ?? [];

            return {
                zoektStats: {
                    duration: Result.Duration,
                    fileCount: Result.FileCount,
                    matchCount: Result.MatchCount,
                    filesSkipped: Result.FilesSkipped,
                    contentBytesLoaded: Result.ContentBytesLoaded,
                    indexBytesLoaded: Result.IndexBytesLoaded,
                    crashes: Result.Crashes,
                    shardFilesConsidered: Result.ShardFilesConsidered,
                    filesConsidered: Result.FilesConsidered,
                    filesLoaded: Result.FilesLoaded,
                    shardsScanned: Result.ShardsScanned,
                    shardsSkipped: Result.ShardsSkipped,
                    shardsSkippedFilter: Result.ShardsSkippedFilter,
                    ngramMatches: Result.NgramMatches,
                    ngramLookups: Result.NgramLookups,
                    wait: Result.Wait,
                    matchTreeConstruction: Result.MatchTreeConstruction,
                    matchTreeSearch: Result.MatchTreeSearch,
                    regexpsConsidered: Result.RegexpsConsidered,
                    flushReason: Result.FlushReason,
                },
                files,
                repositoryInfo: Array.from(repos.values()).map((repo) => ({
                    id: repo.id,
                    codeHostType: repo.external_codeHostType,
                    name: repo.name,
                    displayName: repo.displayName ?? undefined,
                    webUrl: repo.webUrl ?? undefined,
                })),
                isBranchFilteringEnabled: isBranchFilteringEnabled,
                stats: {
                    matchCount: files.reduce(
                        (acc, file) =>
                            acc + file.chunks.reduce(
                                (acc, chunk) => acc + chunk.matchRanges.length,
                                0,
                            ),
                        0,
                    )
                }
            } satisfies SearchResponse;
        });

        return parser.parseAsync(searchBody);
    }));