#!/usr/bin/env python3
"""OptMem: a permanent, append-only memory for AI agents.

  memo wake                print who you are
  memo note "..."          record a memory
  memo sleep [id "..."]    compress
  memo recall <regex>      search the raw log
  memo forget <id>         drop a wrong summary so it is compressed again
  memo import <file>       bulk-append historical memories (bootstrap only)

Everything lives in $MEMORY_DIR as two append-only text files. See README.md.
"""

import datetime
import fcntl
import os
import re
import sys

sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
from blocks import complete, cover  # noqa: E402

ENTRY_CHARS = 280
WAKE_LINES = 320
RAW_MAX = 16  # blocks up to this many memories compress from the raw log


# ---------------------------------------------------------------- store

def store():
    d = os.environ.get("MEMORY_DIR")
    if not d:
        die("MEMORY_DIR is not set. It must name this machine's memory "
            "directory, e.g. export MEMORY_DIR=~/memory")
    d = os.path.expanduser(d)
    os.makedirs(d, exist_ok=True)
    for name in ("LOG.txt", "TREE.txt"):
        p = os.path.join(d, name)
        if not os.path.exists(p):
            open(p, "a").close()
    return d


def config(d):
    global ENTRY_CHARS, WAKE_LINES
    p = os.path.join(d, "config")
    if not os.path.exists(p):
        with open(p, "w") as f:
            f.write("ENTRY_CHARS=%d\nWAKE_LINES=%d\n" % (ENTRY_CHARS, WAKE_LINES))
        return
    for line in open(p):
        line = line.split("#")[0].strip()
        if "=" not in line:
            continue
        k, v = (s.strip() for s in line.split("=", 1))
        if k == "ENTRY_CHARS":
            ENTRY_CHARS = int(v)
        elif k == "WAKE_LINES":
            WAKE_LINES = int(v)


def read_log(d):
    """[(id, date, text)] in order."""
    out = []
    for line in open(os.path.join(d, "LOG.txt")):
        line = line.rstrip("\n")
        if not line:
            continue
        head, _, text = line.partition(" ")
        date, _, text = text.partition(" ")
        out.append((int(head[1:]), date, text))
    return out


def read_tree(d):
    """{(lo,hi): text}"""
    out = {}
    for line in open(os.path.join(d, "TREE.txt")):
        line = line.rstrip("\n")
        if not line:
            continue
        head, _, text = line.partition(" ")
        lo, _, hi = head.partition("-")
        out[(int(lo), int(hi))] = text
    return out


def rewrite_tree(d, keep):
    """Replace TREE.txt. Legal only because TREE.txt is a CACHE of a pure
    function of LOG.txt -- the log itself is never rewritten by anything."""
    lock = open(os.path.join(d, ".lock"), "w")
    fcntl.flock(lock, fcntl.LOCK_EX)
    try:
        tmp = os.path.join(d, "TREE.txt.new")
        with open(tmp, "w") as f:
            for (lo, hi), text in keep:
                f.write("%d-%d %s\n" % (lo, hi, text))
            f.flush()
            os.fsync(f.fileno())
        os.replace(tmp, os.path.join(d, "TREE.txt"))
    finally:
        fcntl.flock(lock, fcntl.LOCK_UN)
        lock.close()


def append(d, name, lines):
    """Append under an exclusive lock. The only way anything is ever written."""
    lock = open(os.path.join(d, ".lock"), "w")
    fcntl.flock(lock, fcntl.LOCK_EX)
    try:
        with open(os.path.join(d, name), "a") as f:
            for line in lines:
                f.write(line + "\n")
            f.flush()
            os.fsync(f.fileno())
    finally:
        fcntl.flock(lock, fcntl.LOCK_UN)
        lock.close()


def die(msg):
    print(msg, file=sys.stderr)
    sys.exit(1)


def check(text):
    text = text.strip()
    if not text:
        die("REJECTED: empty.")
    if "\n" in text or "\r" in text:
        die("REJECTED: %d lines. A memory is exactly one line." %
            (text.count("\n") + 1))
    if len(text) > ENTRY_CHARS:
        die("REJECTED: %d chars, %d over the %d limit. Compress it further."
            % (len(text), len(text) - ENTRY_CHARS, ENTRY_CHARS))
    return text


# ---------------------------------------------------------------- naps

def pending(log, tree):
    """Blocks that can be built and have not been. Smallest first, so a
    block's two halves are always available before the block itself."""
    return [b for b in complete(len(log)) if b not in tree]


def nap_prompt(d, log, tree, todo):
    lo, hi = todo[0]
    if hi - lo <= RAW_MAX:
        body = "\n".join("  #%d %s %s" % log[i] for i in range(lo, hi))
        what = "these %d memories" % (hi - lo)
    else:
        mid = (lo + hi) // 2
        body = "\n".join("  %s" % tree[(a, b)] for a, b in
                         ((lo, mid), (mid, hi)))
        what = "these two summaries"
    return (
        "You are dreaming. Compress {what} into ONE line of at most {n} "
        "characters.\nKeep every name, number, date and decision. Drop wording, "
        "not facts.\nInvent nothing. Write it as a memory, not as a description "
        "of memories.\n\n{body}\n\nThen run exactly:\n"
        "  memo sleep {lo}-{hi} \"<your line>\"\n\n"
        "{left} nap(s) left after this one."
    ).format(what=what, n=ENTRY_CHARS, body=body, lo=lo, hi=hi,
             left=len(todo) - 1)


# ---------------------------------------------------------------- commands

def cmd_wake(d, args):
    log, tree = read_log(d), read_tree(d)
    todo = pending(log, tree)
    if todo:
        print("YOU CANNOT WAKE UP YET: %d compression(s) are pending, and a "
              "memory\nwith work left in it is not yet the truth. Sleep first "
              "-- it is quick.\n" % len(todo))
        print(nap_prompt(d, log, tree, todo))
        sys.exit(1)
    if not log:
        print("You have no memories yet. This is your first moment.\n"
              "Record what matters with: memo note \"...\"")
        return
    for lo, hi in cover(len(log), WAKE_LINES):
        if hi - lo == 1:
            print("#%d %s %s" % log[lo])
        else:
            print("#%d-%d %s" % (lo, hi - 1, tree[(lo, hi)]))


def cmd_note(d, args):
    if len(args) != 1:
        die("usage: memo note \"<one line, at most %d chars>\"" % ENTRY_CHARS)
    text = check(args[0])
    log = read_log(d)
    date = datetime.date.today().isoformat()
    append(d, "LOG.txt", ["#%d %s %s" % (len(log), date, text)])
    print("ok, memory #%d." % len(log))
    log, tree = read_log(d), read_tree(d)
    todo = pending(log, tree)
    if todo:
        print("\n" + nap_prompt(d, log, tree, todo))


def cmd_sleep(d, args):
    log, tree = read_log(d), read_tree(d)
    if args:
        if len(args) != 2:
            die("usage: memo sleep <lo>-<hi> \"<one line>\"")
        m = re.fullmatch(r"(\d+)-(\d+)", args[0])
        if not m:
            die("REJECTED: '%s' is not a block id. Copy it from the prompt."
                % args[0])
        block = (int(m.group(1)), int(m.group(2)))
        if block in tree:
            print("Already dreamt; another session got there first. Skipping.")
        elif block not in pending(log, tree):
            die("REJECTED: block %d-%d is not ready to be compressed. Run "
                "`memo sleep` for the block you should be working on."
                % block)
        else:
            text = check(args[1])
            append(d, "TREE.txt", ["%d-%d %s" % (block[0], block[1], text)])
            print("ok, %d-%d remembered." % block)
        log, tree = read_log(d), read_tree(d)
    todo = pending(log, tree)
    if not todo:
        print("You woke up. Nothing left to compress.")
        return
    print("\n" + nap_prompt(d, log, tree, todo))


def cmd_forget(d, args):
    """A summary can be wrong -- mistyped, or a bad compression. Drop it and
    everything built on top of it; the next sleep computes them again. The log
    is untouched, so nothing is ever actually lost."""
    if len(args) != 1:
        die("usage: memo forget <lo>-<hi>")
    m = re.fullmatch(r"(\d+)-(\d+)", args[0])
    if not m:
        die("REJECTED: '%s' is not a block id." % args[0])
    lo, hi = int(m.group(1)), int(m.group(2))
    tree = read_tree(d)
    doomed = [b for b in tree if b[0] <= lo and hi <= b[1]]
    if not doomed:
        die("There is no summary covering %d-%d to forget." % (lo, hi))
    rewrite_tree(d, [(b, t) for b, t in sorted(tree.items()) if b not in doomed])
    print("forgot %s. They will be compressed again on your next sleep."
          % " ".join("%d-%d" % b for b in sorted(doomed)))


def cmd_recall(d, args):
    if len(args) != 1:
        die("usage: memo recall <regex>")
    try:
        pat = re.compile(args[0], re.I)
    except re.error as e:
        die("bad regex: %s" % e)
    hits = [e for e in read_log(d) if pat.search(e[2])]
    if not hits:
        print("Nothing in your memory matches that.")
        return
    for e in hits:
        print("#%d %s %s" % e)
    print("\n%d memories matched." % len(hits))


def cmd_import(d, args):
    """Bulk-append historical memories: 'YYYY-MM-DD <text>' per line.
    For bootstrapping an identity from older records. Used once."""
    if len(args) != 1:
        die("usage: memo import <file>   # lines of 'YYYY-MM-DD <text>'")
    log = read_log(d)
    n = len(log)
    last = log[-1][1] if log else "0000-00-00"
    out = []
    for i, line in enumerate(open(args[0]), 1):
        line = line.rstrip("\n")
        if not line.strip():
            continue
        date, _, text = line.partition(" ")
        if not re.fullmatch(r"\d{4}-\d{2}-\d{2}", date):
            die("line %d: expected 'YYYY-MM-DD <text>', got: %s" % (i, line))
        if date < last:
            die("line %d: date %s is older than the previous memory (%s). "
                "Memories must be in order." % (i, date, last))
        text = text.strip()
        if not text or len(text) > ENTRY_CHARS:
            die("line %d: %d chars (limit %d)." % (i, len(text), ENTRY_CHARS))
        out.append("#%d %s %s" % (n + len(out), date, text))
        last = date
    append(d, "LOG.txt", out)
    print("imported %d memories (#%d..#%d)." % (len(out), n, n + len(out) - 1))
    todo = pending(read_log(d), read_tree(d))
    if todo:
        print("%d compressions are now pending. Run `memo sleep` until it "
              "says you woke up." % len(todo))


COMMANDS = {"wake": cmd_wake, "note": cmd_note, "sleep": cmd_sleep,
            "recall": cmd_recall, "forget": cmd_forget, "import": cmd_import}


def main():
    if len(sys.argv) < 2 or sys.argv[1] not in COMMANDS:
        print(__doc__.strip())
        sys.exit(0 if len(sys.argv) < 2 else 1)
    d = store()
    config(d)
    COMMANDS[sys.argv[1]](d, sys.argv[2:])


if __name__ == "__main__":
    main()