import nodePath from 'node:path';
import fs from 'node:fs';
import { strict as assert } from "node:assert";
import { ZipFS } from "./zipFs.ts";
import { $, ProcessOutput, quote } from "zx";
import { parallel } from "./parallel.ts";

$.verbose = false;

type FSImpl = {
  isZip?: boolean;
  zipPath?: string;
  init?(): Promise<void>;
  ready?: boolean;

  globSync: typeof fs["globSync"];
  statSync: typeof fs["statSync"];
  existsSync: typeof fs["existsSync"];

  // Required by glob
  lstatSync: typeof fs["lstatSync"];
  // Needs to include withFileTypes DirEnt variant
  readdir: typeof fs["readdir"];
  readdirSync: typeof fs["readdirSync"];
  readlinkSync: typeof fs["readlinkSync"];
  realpathSync: typeof fs["realpathSync"];
  promises: {
    lstat: typeof fs.promises["lstat"];
    // Needs to include withFileTypes DirEnt
    readdir: typeof fs.promises["readdir"];
    readlink: typeof fs.promises["readlink"];
    realpath: typeof fs.promises["realpath"];
  }
};
const defaultFSImpl =  fs;

function safe(s: string) {
  return s.replace(/[^a-zA-Z0-9_]/g, '_');
}


interface TaskTargetOp {
  type: "read" | "mid";
  toShell(target: TaskTarget): string | undefined;
  clone(): TaskTargetOp;
}
class TaskTargetRead implements TaskTargetOp {
  get type(){ return "read" as const; }
  toShell(target: TaskTarget) {
    if (target.fsImpl.isZip) {
      // Read the file to stdout from the target inside the zip file
      // This relies on the internals of fsImpl a bit to have the path to
      // the root zip so we can create a command against it
      assert(target.fsImpl.zipPath, "Should have a zipPath");
      return `7z x ${quote(target.fsImpl.zipPath)} -so ${quote(target.path)}`;
    }

    return `cat ${quote(target.path)}`;
  }
  clone() {
    return new TaskTargetRead();
  }
}

type ValidCmd = string | string[] | ((t: TaskTarget)=>string) | ((t: TaskTarget)=>string[]);
class TaskTargetCmd implements TaskTargetOp {
  get type(){ return "mid" as const; }
  /**What nodejs spawn() and execFile() take
   * [cmd, ...args]: string[]
   */
  cmd: ValidCmd;
  static parse(target: TaskTarget, v: string | string[] | ((t: TaskTarget)=>string) | ((t: TaskTarget)=>string[])): string[] {
    if (typeof v === "function") {
      v = v(target);
    }
    if (typeof v === "string") {
      v = v.split(/\s+/);
    }
    return v;
  }
  constructor(cmd: ValidCmd) {
    this.cmd = cmd;
  }
  toShell(target: TaskTarget) {
    const parsedCmd = TaskTargetCmd.parse(target, this.cmd);
    const out = parsedCmd
      .map(c => {
        let sh = c.replace(/\n/g, "")
        return quote(sh);
      });

    return out.join(" ");
  }
  clone() {
    return new TaskTargetCmd(this.cmd);
  }
}

type ValidId = string | ((t: TaskTarget)=>string);
export const COLUMN_TYPES = {
  /**A numeric value*/
  "numeric": {},
  /**ISO Datetime*/
  "isodatetime": {},
  /**Urls*/
  "url": {},
  /**Freetext*/
  "text": {},
  /**For anything untyped*/
  "any": {},
  /**The sender/originator of a row (maps to Owner in Timelinize)*/
  "sender": {},
  /**The receiver/recipient of a row (maps to RelSent entity in Timelinize)*/
  "receiver": {},
  /**Latitude coordinate*/
  "lat": {},
  /**Longitude coordinate*/
  "lng": {},
  "TODO": {}
};

/**Column metadata. Just a string into the TYPES*/
type ColumnMeta = (keyof typeof COLUMN_TYPES | undefined);
// Make non-optional version of just the metadata values of TaskTarget
type TaskTargetMeta = Required<Pick<TaskTarget, "idValue" | "perRowDescription" | "perRowTags" | "columnMeta" | "aggregate" | "metaIdValue" | "aggregateColumns">>;

export class TaskTarget {
  /**The current path pointed to by this TaskTarget*/
  path: string;
  /**The fsImpl used to access the .path*/
  fsImpl: FSImpl = defaultFSImpl;
  /**The pipeline of things to do to the above path to get an stdout of the output*/
  pipeline: TaskTargetOp[];

  // == Metadata, user configurable, no good defaults ==
  /**Id of the TaskTarget
   * string - Static id
   * fn returning string - Function can derive the id from a task target even after a glob() and cd() operation 
   **/
  idValue?: ValidId;
  /**For every output CSV, this defines a description of that CSV per-row
   * Use the items {0}, {1} to template
   * Example: For a CSV with a row format like ["time", "sender", "sendee", "message"]
   * you might do something like '"{3}" sent from {2} to {1}'
   * */
  perRowDescription?: string;
  /**A CSV of tags that is added to every row of the table (TODO: no template functionality currently)*/
  perRowTags?: string;
  /**Metadata about the columns*/
  columnMeta?: ColumnMeta[];
  /**Whether or not to aggregate to a single task (everything with the id value idValue)*/
  aggregate?: boolean;
  /**Names of the columns to aggregate with*/
  aggregateColumns?: string[];
  /**A metadata TaskTarget for this TaskTarget, if one exists*/
  metaIdValue?: ValidId;

  constructor(path: string){
    this.path = path;
    this.pipeline = [];
  }

  exists() {
    return this.fsImpl.existsSync(this.path);
  }

  _joinPath(path: string) {
    let finalPath = path;
    if (!path.startsWith('/')) {
      finalPath = nodePath.join(this.path, path)
    }
    return finalPath;
  }

  get basename() {
    return safe(nodePath.basename(this.path));
  }
  basenameN(n: number) {
    return this.path
      .split("/")
      .map(s => safe(s))
      .slice(-n)
      .join("___");
  }

  get id() {
    assert(this.idValue, `TaskTarget for path "${this.path}" must have an id`);
    if (typeof this.idValue === "function") {
      return safe(this.idValue(this));
    }
    return safe(this.idValue);
  }
  get metaId() {
    if (!this.metaIdValue) {
      return undefined;
    }
    if (typeof this.metaIdValue === "function") {
      return safe(this.metaIdValue(this));
    }
    return safe(this.metaIdValue);
  }

  /**Changes the current directory of the target*/
  cd(path: string): TaskTarget {
    this.path = this._joinPath(path);
    return this;
  }
  /**Unzips the file pointed to by the current TaskTarget*/
  async unzip(): Promise<TaskTarget> {
    const zfs = new ZipFS(this.path);
    await zfs.init();
    this.path = ""; // target is now rooted at the base of its respective zipfs
    this.fsImpl = zfs.getImpl() as any;
    return this;
  }

  /**Get a glob off of the target*/
  glob(globPath: string): TaskTarget[] {
    globPath = this._joinPath(globPath);
    const items = this.fsImpl.globSync(globPath);
    const ret = items.map(i => new TaskTarget(i));
    // TODO: This should probably clone()
    ret.forEach(t => t.fsImpl = this.fsImpl); // Should all use the same fsImpl
    return ret;
  }

  /**Clones the TaskTarget*/
  clone(): TaskTarget {
    const t = new TaskTarget(this.path);
    t.fsImpl = this.fsImpl; // holds no state, just needs same impl
    t.pipeline = this.pipeline.slice()
      .map(p => p.clone());
    // metadata
    t.idValue = this.idValue;
    t.perRowDescription = this.perRowDescription;
    t.perRowTags = this.perRowTags;
    t.columnMeta = this.columnMeta?.slice();
    t.metaIdValue = this.metaIdValue;
    t.aggregate = this.aggregate;
    t.aggregateColumns = this.aggregateColumns?.slice();
    return t;
  }

  pushToPipeline(v: TaskTargetOp) {
    if (v.type === "read") {
      assert(this.pipeline.length === 0, "A read can only be the first item in a pipeline");
    }

    this.pipeline.push(v);
  }

  toShell() {
    const shell = this.pipeline
      .map(p => p.toShell(this))
      .filter(p => !!p) // remove empty strings and undefined
      .join(" | ")
    return shell;
  }

  cmd(cmd: ValidCmd) {
    this.pushToPipeline(new TaskTargetCmd(cmd));
    return this;
  }
  read() {
    this.pushToPipeline(new TaskTargetRead());
    return this;
  }
  assignMeta(meta: Partial<TaskTargetMeta>) {
    Object.assign(this, {
      ...meta,
      // Clone this deeply so no shared object references
      columnMeta: meta.columnMeta?.slice()
    });
    return this;
  }
}

export interface PipelineOp {
  (targets: TaskTarget[]): TaskTarget[] | Promise<TaskTarget[]>;
}

export function cd(path: string): PipelineOp {
  return (targets: TaskTarget[]) => targets.map(t => t.clone().cd(path));
}
export function glob(globPath: string): PipelineOp {
  return (targets: TaskTarget[]) => targets.map(t => t.glob(globPath)).flat();
}
export function unzip(): PipelineOp {
  return async (targets: TaskTarget[]) => Promise.all(targets.map(t => t.unzip()));
}
export function read(): PipelineOp {
  return (targets: TaskTarget[]) => targets.map(t => t.clone().read())
}
export function cmd(cmd: ValidCmd): PipelineOp {
  return (targets: TaskTarget[]) => targets.map(t => t.clone().cmd(cmd))
}
export function assignMeta(meta: Partial<TaskTargetMeta>): PipelineOp {
  return (targets: TaskTarget[]) => targets.map(t => t.clone().assignMeta(meta))
}

export function each(fn: (t: TaskTarget)=>TaskTarget): PipelineOp {
  return (targets: TaskTarget[])=> targets.map(fn);
}
export function pipe(...ops: PipelineOp[]): PipelineOp {
  return async (targets: TaskTarget[]) => {
    for (const op of ops) {
      targets = await op(targets);
    }
    return targets;
  };
}
export function branch(...ops: PipelineOp[]): PipelineOp {
  return async (targets: TaskTarget[]) => {
    const targetsArrays = await Promise.all(ops.map(op => op(targets)));
    return targetsArrays.flat();
  };
}
export function branchGen(genFn: ()=>Generator<PipelineOp>): PipelineOp {
  const opsToBranch = Array.from(genFn());
  return (targets: TaskTarget[]) => {
    return branch(...opsToBranch)(targets);
  };
}

export async function execPaths(entries: ({path: string, op: PipelineOp })[]) {
  return (await Promise.all(
    // Map every entry path into a TaskTarget and run the PipelineOp with
    // that TaskTarget
    entries
      .map(async ({path,op})=>{
        const targets = [new TaskTarget(path)];
        return await op(targets);
      })
  )).flat();
}


/**Verify, anything that fails is skipped and throws an error*/
export async function verify(targets: TaskTarget[]) {
  const outTargets: TaskTarget[] = [];
  for (const t of targets) {
    // Make sure fsImpl is ready
    // TODO: DO NOT PUT THIS IN VERIFY, this should go somewhere in the task building stuff...
    if ("ready" in t.fsImpl && !t.fsImpl.ready && t.fsImpl.init) {
      await t.fsImpl.init();
    }
    // TODO: Probably remove or assert as incorrect
    if (t.pipeline.length <= 0) {
      continue; // Tasks with empty pipelines are no-ops, remove
    }
    if (!t.exists()) {
      console.warn(`Missing target ${t.path}`);
      continue;
    }

    outTargets.push(t);
  }

  return outTargets;
}

export interface ProcessOutputAggregate {
  stdout: string;
  stderr: string;
  exitCodes: (number | null)[];
  duration: number;
  ok: boolean;
}
export interface ProcessOutputSimple {
  stdout: string;
  stderr: string;
  exitCode: number;
  duration: number;
  ok: boolean;
}

function combineProcessOutputAggregate(poa: ProcessOutputAggregate | undefined, t: TaskTarget, po: ProcessOutput) {
  if (!poa) {
    assert(t.aggregateColumns, "aggregate TaskTarget must have aggregateColumns");
    const headers = t.aggregateColumns.join(",") + "\n";
    return {
      stdout: headers + po.stdout,
      stderr: po.stderr,
      exitCodes: [po.exitCode],
      duration: po.duration,
      ok: po.ok
    };
  }

  // Comes with a builtin "\n" from jq on stdout and stderr, no need to add
  // a trailing one
  poa.stdout += po.stdout;
  poa.stderr += po.stderr;
  poa.exitCodes.push(po.exitCode);
  poa.duration += po.duration;
  poa.ok &&= po.ok;
  return poa;
}

export interface RunOutput {
  target: TaskTarget,
  result: ProcessOutput | ProcessOutputAggregate | ProcessOutputSimple
}

export async function run(target: TaskTarget): Promise<ProcessOutput> {
  const command = target.toShell();
  return await $({ nothrow: true })`bash -c ${command}`;
}

export async function runAll(targets: TaskTarget[]): Promise<RunOutput[]> {
  const finalTargets = await verify(targets);
  const results = await parallel(finalTargets, run, true);

  const nonAggregateTargets: TaskTarget[] = finalTargets.filter(t => !t.aggregate);
  const nonAggregateResults: RunOutput[] = [];
  const aggregateResultsMap: Record<string, RunOutput> = {};

  // == Aggregate tables ==
  // Some TaskTargets have .aggregate: true, which means they should all be combined
  // into a single task with the id of the .id property
  for (const [idx, r] of results.entries()) {
    const t = finalTargets[idx];
    if (!t.aggregate) {
      nonAggregateResults.push({
        target: t,
        result: r
      });
      continue;
    }
    const aggregateId = t.id;
    const prevResult = aggregateResultsMap[aggregateId]?.result;
    aggregateResultsMap[aggregateId] = {
      target: t, // Use target t for metadata, so it will use the last target
      result: combineProcessOutputAggregate(prevResult as (ProcessOutputAggregate | undefined), t, r)
    };
  }

  // == Metadata table ==
  // Each TaskTarget has things like perRowDescription and other things we want to store
  // and output. this creates a single TaskTarget for all that perTable metadata
  function csvEscape(s: string | undefined) {
    if (s === undefined) {
      return "";
    }
    if (s.includes("\"") || s.includes(",") || s.includes("\n")) {
      return `"${s.replace(/\"/g, "\"\"")}"`;
    }
    return s;
  }
  let metadataCSV = "id,perRowDescription,perRowTags,columnMeta,metaId\n";
  for (const t of nonAggregateTargets) {
    const tableNamePart = t.id;
    const perRowDescriptionPart = t.perRowDescription;
    const perRowTagsPart = t.perRowTags;
    const columnMetaPart = t.columnMeta?.join(",") ?? "";
    const metaIdPart = t.metaId;
    metadataCSV += [
      csvEscape(tableNamePart),
      csvEscape(perRowDescriptionPart),
      csvEscape(perRowTagsPart),
      csvEscape(columnMetaPart),
      csvEscape(metaIdPart)
    ].join(",") + "\n";
  }
  // Won't be removed by verify() because we're adding it after that's used
  // TODO: Would be nice to bake this into TaskTarget/verify for tasks that dont point
  // to a real path
  const metadataTarget = new TaskTarget("<none>");
  metadataTarget
    // id, perRowDescription, perRowTags, columnMeta, metaId
    .assignMeta({
      idValue: "base_data_manager_metadata",
      columnMeta: ["any", "any", "any", "any", "any"],
      perRowTags: "internal",
    });
  const metadataResult= {
    stdout: metadataCSV,
    stderr: "",
    exitCode: 0,
    duration: 0, // TODO
    ok: true
  };
  const metadataRunOutput: RunOutput = { target: metadataTarget, result: metadataResult };

  const aggregateResults: RunOutput[] = Object.values(aggregateResultsMap);
  return aggregateResults.concat(nonAggregateResults).concat(metadataRunOutput);
}