#!/usr/bin/env bun
import { existsSync, readFileSync, unlinkSync, writeFileSync } from "node:fs";
import { spawnSync } from "node:child_process";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { parseArgs } from "node:util";
import { DateTime } from "luxon";
import * as chrono from "chrono-node";
import { loadConfig } from "./config.ts";
import {
  type Entry,
  filterEntries,
  type FilterParams,
  makeEntry,
  matchesFilter,
  parseEntries,
  printEntry,
  renderEntry,
  saveEntries,
} from "./mod.ts";

function partition<T>(arr: T[], pred: (e: T) => boolean): [T[], T[]] {
  const yes: T[] = [], no: T[] = [];
  for (const e of arr) (pred(e) ? yes : no).push(e);
  return [yes, no];
}

function tryDate(d?: unknown): DateTime | undefined {
  if (typeof d !== "string") return undefined;
  const parsed = chrono.parseDate(d);
  return parsed ? DateTime.fromJSDate(parsed) : undefined;
}

function printFilteredEntries(
  entries: Entry[],
  params: FilterParams,
  summary: boolean,
): void {
  const filtered = filterEntries(entries, params);
  let first = true;
  for (const entry of filtered) {
    if (!first && !summary) {
      console.log();
    }
    first = false;
    printEntry(entry, summary);
  }
}

function edit(
  body: string,
  editor: string[],
): string | undefined {
  const temp = join(tmpdir(), `hayom-${crypto.randomUUID()}.hayom`);
  try {
    writeFileSync(temp, body);
    const result = spawnSync(editor[0], [...editor.slice(1), temp], {
      stdio: "inherit",
    });
    if (result.status === 0) {
      return readFileSync(temp, "utf-8");
    }
    console.error("Aborted.");
  } finally {
    try { unlinkSync(temp); } catch {}
  }
}

function editFilteredEntries(
  entries: Entry[],
  filter: FilterParams,
  editor: string[],
): Entry[] | undefined {
  const [toEdit, toKeep] = partition(entries, (e) => matchesFilter(e, filter));
  const result = edit(toEdit.map(renderEntry).join("\n"), editor);
  if (result == null) return undefined;
  return [...toKeep, ...parseEntries(result.replace("\r", ""))];
}

function printHelp(): void {
  console.log(`
usage: hayom [-j journal] ...
options:
   --count | -n:   number of entries to print
   --edit | -e:    edit entries
   --from | -f:    from timestamp
   --journal | -j: journal to use
   --on:           on timestamp
   --summary | -s: print summary line only
   --to | -t:      to timestamp
`);
}

function main(): void {
  const config = loadConfig();

  const { values: opts, positionals } = parseArgs({
    args: process.argv.slice(2),
    allowPositionals: true,
    options: {
      summary: { type: "boolean", short: "s" },
      edit: { type: "boolean", short: "e" },
      from: { type: "string", short: "f" },
      journal: { type: "string", short: "j" },
      count: { type: "string", short: "n" },
      to: { type: "string", short: "t" },
      on: { type: "string" },
      help: { type: "boolean", short: "h" },
    },
  });

  if (opts.help) {
    printHelp();
    return;
  }

  const journal = opts.journal ?? config.default;
  const path = config.journals[journal].journal;

  if (!existsSync(path)) {
    writeFileSync(path, "");
  }

  const entries = parseEntries(readFileSync(path, "utf-8").replace("\r", ""));

  if (
    opts.from != null || opts.to != null || opts.on != null || opts.count != null ||
    (positionals.length > 0 && positionals.every((e) => e[0] === "@"))
  ) {
    let from = tryDate(opts.from);
    let to = tryDate(opts.to);
    if (opts.on) {
      const on = tryDate(opts.on);
      if (typeof on !== "object") {
        throw new Error("Bad date");
      }
      [from, to] = [on.startOf("day"), on.endOf("day")];
    }
    const tags = positionals.filter((arg) => arg.match(/^@./));

    const filter: FilterParams = {
      from,
      to,
      tags,
      limit: opts.count ? parseInt(opts.count) : undefined,
    };

    if (opts.edit) {
      const newEntries = editFilteredEntries(entries, filter, config.editor);
      if (newEntries != null) {
        saveEntries(path, newEntries);
      }
    } else {
      printFilteredEntries(entries, filter, opts.summary ?? false);
    }
  } else {
    const rawEntry = positionals.length > 0
      ? positionals.join(" ")
      : edit("", config.editor);
    if (rawEntry && rawEntry.trim() !== "") {
      const entry = makeEntry(rawEntry);
      entries.push(entry);
      saveEntries(path, entries);
    }
  }
}

if (import.meta.main) {
  main();
}