#!/usr/bin/env python3
from __future__ import annotations

import argparse

from common import (
    BACKLOG_PATH,
    ARCHIVE_PATH,
    IMPLEMENTATION_PATH,
    PROOF_PATH,
    RESEARCH_ACTIVE_PATH,
    append_archive_line,
    backlog_entry_map,
    git_commit,
    remove_backlog_ids,
    save_text,
    slugify,
    today_iso,
)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Open a new implementation or research turn.")
    parser.add_argument("--lane", required=True, choices=("implementation", "research"))
    parser.add_argument("--title", required=True, help="Turn title.")
    parser.add_argument("--summary", required=True, help="One-line proof or charter summary.")
    parser.add_argument(
        "--pick",
        action="append",
        default=[],
        help="Backlog ID to pull into the turn. Repeat as needed.",
    )
    parser.add_argument(
        "--commit",
        action="store_true",
        help="Commit the planning change automatically.",
    )
    parser.add_argument(
        "--force",
        action="store_true",
        help="Replace an already-open turn instead of refusing.",
    )
    return parser.parse_args()


def render_selected(ids: list[str], items: dict[str, str]) -> str:
    if not ids:
        return "- none selected"
    return "\n".join(f"- [{item_id}] {items[item_id]}" for item_id in ids)


def open_implementation_turn(title: str, summary: str, selected: str) -> None:
    opened = today_iso()
    save_text(
        PROOF_PATH,
        f"""# Implementation Proof: {title}

Status: open
Opened: {opened}

## Hypothesis
{summary}

## Scope
{selected}

## Non-goals
- unchanged from `THESIS.md` unless the user approves otherwise

## Definition of done
- current turn implementation is validated with direct evidence
- remaining fakes are listed plainly
""",
    )
    save_text(
        IMPLEMENTATION_PATH,
        f"""# Implementation Turn: {title}

Status: open
Opened: {opened}

## Goal
{summary}

## Selected backlog items
{selected}

## Notes
- Fill in the concrete implementation plan before coding if the live plan no longer matches the turn.
""",
    )


def open_research_turn(title: str, summary: str, selected: str) -> None:
    opened = today_iso()
    save_text(
        RESEARCH_ACTIVE_PATH,
        f"""# Research Turn: {title}

Status: open
Opened: {opened}

## Charter
{summary}

## Selected backlog items
{selected}

## Hypothesis
TBD by the approved research turn.

## Dataset or source of truth
TBD by the approved research turn.

## Metrics
TBD by the approved research turn.

## Assumptions
TBD by the approved research turn.

## Falsification condition
TBD by the approved research turn.
""",
    )


def main() -> None:
    args = parse_args()
    if args.lane == "implementation":
        if "Status: open" in PROOF_PATH.read_text(encoding="utf-8") and not args.force:
            raise SystemExit("implementation turn already open; close it first or pass --force")
    else:
        if "Status: open" in RESEARCH_ACTIVE_PATH.read_text(encoding="utf-8") and not args.force:
            raise SystemExit("research turn already open; close it first or pass --force")

    entries = backlog_entry_map()
    missing = [item_id for item_id in args.pick if item_id not in entries]
    if missing:
        raise SystemExit(f"unknown backlog IDs: {', '.join(missing)}")

    selected = render_selected(args.pick, entries)

    if args.lane == "implementation":
        open_implementation_turn(args.title, args.summary, selected)
    else:
        open_research_turn(args.title, args.summary, selected)

    if args.pick:
        remove_backlog_ids(args.pick)

    append_archive_line(
        "planning",
        (
            f"- {today_iso()}: opened {args.lane} turn `{slugify(args.title)}` "
            f"from backlog items {', '.join(args.pick) if args.pick else 'none'}."
        ),
    )

    if args.commit:
        commit_paths = [BACKLOG_PATH, ARCHIVE_PATH]
        if args.lane == "implementation":
            commit_paths.extend([PROOF_PATH, IMPLEMENTATION_PATH])
        else:
            commit_paths.append(RESEARCH_ACTIVE_PATH)
        git_commit(
            f"""Open {args.lane} turn: {args.title}

Proof: Establish the approved {args.lane} turn and move selected backlog items into active scope.
Assumptions: The selected backlog items are the approved scope for this turn.
Still fake: Opening a turn changes planning state only; the work itself is not implemented yet.""",
            paths=commit_paths,
        )


if __name__ == "__main__":
    main()