#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Codex Session Start Hook - Inject Trellis context into Codex sessions.

Output format follows Codex hook protocol:
  stdout JSON → { hookSpecificOutput: { hookEventName: "SessionStart", additionalContext: "..." } }
"""

from __future__ import annotations

import json
import os
import re
import subprocess
import sys
import warnings
from io import StringIO
from pathlib import Path

# Force UTF-8 on stdin/stdout/stderr on Windows. Default codepage there is
# cp936 / cp1252 / etc. — non-ASCII content (Chinese task names, prd snippets)
# both in stdin (hook payload from host CLI) and stdout (our emitted blocks)
# raises UnicodeDecodeError / UnicodeEncodeError. Equivalent to `python -X utf8`
# but applied per-stream so we don't depend on host CLI's command wiring.
if sys.platform.startswith("win"):
    import io as _io
    for _stream_name in ("stdin", "stdout", "stderr"):
        _stream = getattr(sys, _stream_name, None)
        if _stream is None:
            continue
        if hasattr(_stream, "reconfigure"):
            try:
                _stream.reconfigure(encoding="utf-8", errors="replace")  # type: ignore[union-attr]
            except Exception:
                pass  # Optional Windows stream setup; keep hook startup non-fatal.
        elif hasattr(_stream, "detach"):
            try:
                setattr(sys, _stream_name, _io.TextIOWrapper(_stream.detach(), encoding="utf-8", errors="replace"))
            except Exception:
                pass  # Optional Windows stream setup; keep hook startup non-fatal.


def _normalize_windows_shell_path(path_str: str) -> str:
    """Normalize Unix-style shell paths to real Windows paths.

    On Windows, shells like Git Bash / MSYS2 / Cygwin may report paths like
    `/d/Users/...` or `/cygdrive/d/Users/...`. `Path.resolve()` will misinterpret
    these as `D:/d/Users...` on drive D: (or similar), breaking repo root
    detection.

    This function is intentionally conservative: it only rewrites patterns that
    unambiguously represent a drive letter mount.
    """
    if not isinstance(path_str, str) or not path_str:
        return path_str

    # Only relevant on Windows; keep other platforms untouched.
    if not sys.platform.startswith("win"):
        return path_str

    p = path_str.strip()

    # Already a Windows drive path (C:\... or C:/...)
    if re.match(r"^[A-Za-z]:[\/]", p):
        return p

    # MSYS/Git-Bash style: /c/Users/... or /d/Work/...
    m = re.match(r"^/([A-Za-z])/(.*)", p)
    if m:
        drive, rest = m.group(1).upper(), m.group(2)
        rest = rest.replace('/', '\\')
        return f"{drive}:\\{rest}"

    # Cygwin style: /cygdrive/c/Users/...
    m = re.match(r"^/cygdrive/([A-Za-z])/(.*)", p)
    if m:
        drive, rest = m.group(1).upper(), m.group(2)
        rest = rest.replace('/', '\\')
        return f"{drive}:\\{rest}"

    # WSL mounted drive (sometimes leaked into env): /mnt/c/Users/...
    m = re.match(r"^/mnt/([A-Za-z])/(.*)", p)
    if m:
        drive, rest = m.group(1).upper(), m.group(2)
        rest = rest.replace('/', '\\')
        return f"{drive}:\\{rest}"

    return path_str


warnings.filterwarnings("ignore")

FIRST_REPLY_NOTICE = """<first-reply-notice>
On the first visible assistant reply in this session, briefly acknowledge that Trellis SessionStart context loaded.
Choose the acknowledgment language in this order:
1. Use the language of the user's current request (the user message that triggered this reply).
2. If that request has no clear natural language, use an explicitly established project communication language.
3. If neither provides a language, output the language-neutral fallback exactly: `Trellis SessionStart ✓`.
Continue directly with the user's request after the acknowledgment.
The acknowledgment must not alter the language used for the remainder of the response.
This notice is one-shot: do not repeat it after the first visible assistant reply in this session.
</first-reply-notice>"""


def should_skip_injection() -> bool:
    if os.environ.get("TRELLIS_HOOKS") == "0":
        return True
    if os.environ.get("TRELLIS_DISABLE_HOOKS") == "1":
        return True
    return os.environ.get("CODEX_NON_INTERACTIVE") == "1"


def configure_project_encoding(project_dir: Path) -> None:
    """Reuse Trellis' shared Windows stdio encoding helper before JSON output."""
    scripts_dir = project_dir / ".trellis" / "scripts"
    if str(scripts_dir) not in sys.path:
        sys.path.insert(0, str(scripts_dir))

    try:
        from common import configure_encoding  # type: ignore[import-not-found]

        configure_encoding()
    except Exception:
        pass  # Optional encoding helper; host defaults are still usable.


def _has_curated_jsonl_entry(jsonl_path: Path) -> bool:
    """Return True iff jsonl has at least one row with a ``file`` field.

    A freshly seeded jsonl only contains a ``{"_example": ...}`` row (no
    ``file`` key) — that is NOT "ready". Readiness requires at least one
    curated entry. Matches the contract used by ``inject-subagent-context.py``.
    """
    try:
        for line in jsonl_path.read_text(encoding="utf-8").splitlines():
            line = line.strip()
            if not line:
                continue
            try:
                row = json.loads(line)
            except json.JSONDecodeError:
                continue
            if isinstance(row, dict) and row.get("file"):
                return True
    except (OSError, UnicodeDecodeError):
        return False
    return False


def read_file(path: Path, fallback: str = "") -> str:
    try:
        return path.read_text(encoding="utf-8")
    except (FileNotFoundError, PermissionError):
        return fallback


def _resolve_context_key(project_dir: Path, hook_input: dict) -> str | None:
    scripts_dir = project_dir / ".trellis" / "scripts"
    if str(scripts_dir) not in sys.path:
        sys.path.insert(0, str(scripts_dir))
    try:
        from common.active_task import resolve_context_key  # type: ignore[import-not-found]
    except Exception:
        return None
    return resolve_context_key(hook_input, platform="codex")


def _resolve_active_task(trellis_dir: Path, hook_input: dict):
    scripts_dir = trellis_dir / "scripts"
    if str(scripts_dir) not in sys.path:
        sys.path.insert(0, str(scripts_dir))
    from common.active_task import resolve_active_task  # type: ignore[import-not-found]

    return resolve_active_task(trellis_dir.parent, hook_input, platform="codex")


def run_script(script_path: Path, context_key: str | None = None) -> str:
    try:
        env = os.environ.copy()
        env["PYTHONIOENCODING"] = "utf-8"
        if context_key:
            env["TRELLIS_CONTEXT_ID"] = context_key
        cmd = [sys.executable, "-W", "ignore", str(script_path)]
        result = subprocess.run(
            cmd,
            capture_output=True,
            text=True,
            encoding="utf-8",
            errors="replace",
            timeout=5,
            cwd=str(script_path.parent.parent.parent),
            env=env,
        )
        return result.stdout if result.returncode == 0 else "No context available"
    except (subprocess.TimeoutExpired, FileNotFoundError, PermissionError):
        return "No context available"


def _normalize_task_ref(task_ref: str) -> str:
    normalized = task_ref.strip()
    if not normalized:
        return ""

    path_obj = Path(normalized)
    if path_obj.is_absolute():
        return str(path_obj)

    normalized = normalized.replace("\\", "/")
    while normalized.startswith("./"):
        normalized = normalized[2:]

    if normalized.startswith("tasks/"):
        return f".trellis/{normalized}"

    return normalized


def _resolve_task_dir(trellis_dir: Path, task_ref: str) -> Path:
    normalized = _normalize_task_ref(task_ref)
    path_obj = Path(normalized)
    if path_obj.is_absolute():
        return path_obj
    if normalized.startswith(".trellis/"):
        return trellis_dir.parent / path_obj
    return trellis_dir / "tasks" / path_obj


def _get_task_status(trellis_dir: Path, hook_input: dict) -> str:
    active = _resolve_active_task(trellis_dir, hook_input)
    if not active.task_path:
        return (
            "Status: NO ACTIVE TASK\n"
            "Next: Classify the current turn and ask for task-creation consent "
            "before creating any Trellis task."
        )

    task_ref = active.task_path
    task_dir = _resolve_task_dir(trellis_dir, task_ref)
    if active.stale or not task_dir.is_dir():
        return (
            f"Status: STALE POINTER\nTask: {task_ref}\n"
            "Next: Task directory not found. Run: python3 ./.trellis/scripts/task.py finish"
        )

    task_json_path = task_dir / "task.json"
    task_data: dict = {}
    if task_json_path.is_file():
        try:
            task_data = json.loads(task_json_path.read_text(encoding="utf-8"))
        except (json.JSONDecodeError, PermissionError):
            pass  # Optional task metadata; fall back to generic status.

    task_title = task_data.get("title", task_ref)
    task_status = task_data.get("status", "unknown")

    if task_status == "completed":
        return (
            f"Status: COMPLETED\nTask: {task_title}\n"
            f"Next: Archive with `python3 ./.trellis/scripts/task.py archive {task_dir.name}` "
            "or start a new task."
        )

    has_prd = (task_dir / "prd.md").is_file()
    has_design = (task_dir / "design.md").is_file()
    has_implement = (task_dir / "implement.md").is_file()
    present = [
        name
        for name in ("prd.md", "design.md", "implement.md", "implement.jsonl", "check.jsonl")
        if (task_dir / name).is_file()
    ]
    present_line = ", ".join(present) if present else "none"

    if not has_prd:
        return (
            f"Status: PLANNING\nTask: {task_title}\nPresent: {present_line}\n"
            "Next: Load trellis-brainstorm and write prd.md. Stay in planning."
        )

    if task_status == "planning":
        if has_design and has_implement:
            next_action = "Review planning artifacts with the user before `task.py start`."
        else:
            next_action = (
                "Lightweight task can ask for start review with PRD-only; "
                "complex task must add design.md and implement.md before `task.py start`."
            )
        return (
            f"Status: PLANNING\nTask: {task_title}\nPresent: {present_line}\n"
            f"Next: {next_action}"
        )

    return (
        f"Status: {task_status.upper()}\nTask: {task_title}\nPresent: {present_line}\n"
        "Next: Follow the matching per-turn workflow-state. Context order is jsonl entries, "
        "prd.md, design.md if present, implement.md if present."
    )


def _run_git(repo_root: Path, args: list[str]) -> str:
    try:
        result = subprocess.run(
            ["git", *args],
            capture_output=True,
            text=True,
            encoding="utf-8",
            errors="replace",
            timeout=3,
            cwd=str(repo_root),
        )
    except (subprocess.TimeoutExpired, FileNotFoundError, PermissionError):
        return ""
    if result.returncode != 0:
        return ""
    return result.stdout.strip()


def _format_git_state(repo_root: Path) -> str:
    branch = _run_git(repo_root, ["branch", "--show-current"]) or "(detached)"
    dirty_lines = [
        line for line in _run_git(repo_root, ["status", "--porcelain"]).splitlines()
        if line.strip()
    ]
    dirty_text = "clean" if not dirty_lines else f"dirty {len(dirty_lines)} paths"
    return f"Git: branch {branch}; {dirty_text}."


def _repo_relative(repo_root: Path, path: Path) -> str:
    try:
        return path.relative_to(repo_root).as_posix()
    except ValueError:
        return str(path)


def _collect_spec_index_paths(trellis_dir: Path) -> list[str]:
    paths: list[str] = []
    guides_index = trellis_dir / "spec" / "guides" / "index.md"
    if guides_index.is_file():
        paths.append(".trellis/spec/guides/index.md")

    spec_dir = trellis_dir / "spec"
    if not spec_dir.is_dir():
        return paths

    for sub in sorted(spec_dir.iterdir()):
        if not sub.is_dir() or sub.name.startswith(".") or sub.name == "guides":
            continue
        index_file = sub / "index.md"
        if index_file.is_file():
            paths.append(f".trellis/spec/{sub.name}/index.md")
            continue
        for nested in sorted(sub.iterdir()):
            if not nested.is_dir():
                continue
            nested_index = nested / "index.md"
            if nested_index.is_file():
                paths.append(f".trellis/spec/{sub.name}/{nested.name}/index.md")

    return paths


def _build_compact_current_state(
    trellis_dir: Path,
    hook_input: dict,
    spec_index_paths: list[str],
) -> str:
    repo_root = trellis_dir.parent
    lines: list[str] = []

    try:
        from common.paths import get_active_journal_file, get_developer, get_tasks_dir, count_lines  # type: ignore[import-not-found]
        from common.tasks import iter_active_tasks  # type: ignore[import-not-found]
    except Exception:
        get_active_journal_file = None  # type: ignore[assignment]
        get_developer = None  # type: ignore[assignment]
        get_tasks_dir = None  # type: ignore[assignment]
        count_lines = None  # type: ignore[assignment]
        iter_active_tasks = None  # type: ignore[assignment]

    developer = get_developer(repo_root) if get_developer else None
    lines.append(f"Developer: {developer or '(not initialized)'}")
    lines.append(_format_git_state(repo_root))

    active = _resolve_active_task(trellis_dir, hook_input)
    if active.task_path:
        task_dir = _resolve_task_dir(trellis_dir, active.task_path)
        status = "unknown"
        task_json = task_dir / "task.json"
        if task_json.is_file():
            try:
                data = json.loads(task_json.read_text(encoding="utf-8"))
                if isinstance(data, dict):
                    status = str(data.get("status") or "unknown")
            except (json.JSONDecodeError, OSError):
                pass  # Optional task metadata; fall back to generic status.
        lines.append(f"Current task: {_repo_relative(repo_root, task_dir)}; status={status}.")
    else:
        lines.append("Current task: none.")

    if get_tasks_dir and iter_active_tasks:
        try:
            task_count = sum(1 for _ in iter_active_tasks(get_tasks_dir(repo_root)))
            lines.append(
                f"Active tasks: {task_count} total. Use `python3 ./.trellis/scripts/task.py list --mine` only if needed."
            )
        except Exception:
            pass  # Optional task summary; keep compact state available.

    if get_active_journal_file and count_lines:
        journal = get_active_journal_file(repo_root)
        if journal:
            lines.append(
                f"Journal: {_repo_relative(repo_root, journal)}, {count_lines(journal)} / 2000 lines."
            )

    if spec_index_paths:
        lines.append(f"Spec indexes: {len(spec_index_paths)} available.")

    return "\n".join(lines)


def _extract_range(content: str, start_header: str, end_header: str) -> str:
    """Extract lines starting at `## start_header` up to (but excluding) `## end_header`."""
    lines = content.splitlines()
    start: "int | None" = None
    end: int = len(lines)
    start_match = f"## {start_header}"
    end_match = f"## {end_header}"
    for i, line in enumerate(lines):
        stripped = line.strip()
        if start is None and stripped == start_match:
            start = i
            continue
        if start is not None and stripped == end_match:
            end = i
            break
    if start is None:
        return ""
    return "\n".join(lines[start:end]).rstrip()


_BREADCRUMB_TAG_RE = re.compile(
    r"\[workflow-state:([A-Za-z0-9_-]+)\]\s*\n.*?\n\s*\[/workflow-state:\1\]",
    re.DOTALL,
)


def _strip_breadcrumb_tag_blocks(content: str) -> str:
    stripped = _BREADCRUMB_TAG_RE.sub("", content)
    stripped = re.sub(r"<!--.*?-->", "", stripped, flags=re.DOTALL)
    stripped = re.sub(r"^\[(?!/?workflow-state:)/?[^\]\n]+\]\s*\n?", "", stripped, flags=re.MULTILINE)
    return re.sub(r"\n{3,}", "\n\n", stripped).strip()


def _build_workflow_toc(workflow_path: Path) -> str:
    """Inject only the compact Phase Index summary for SessionStart."""
    content = read_file(workflow_path)
    if not content:
        return "No workflow.md found"

    out_lines = [
        "# Development Workflow - Session Summary",
        "Full guide: .trellis/workflow.md. Step detail: `python3 ./.trellis/scripts/get_context.py --mode phase --step <X.Y>`.",
        "",
    ]

    phases = _extract_range(content, "Phase Index", "Phase 1: Plan")
    if phases:
        out_lines.append(_strip_breadcrumb_tag_blocks(phases).rstrip())

    return "\n".join(out_lines).rstrip()


def main() -> None:
    if should_skip_injection():
        sys.exit(0)

    # Read hook input from stdin
    try:
        hook_input = json.loads(sys.stdin.read())
        if not isinstance(hook_input, dict):
            hook_input = {}
        project_dir = Path(_normalize_windows_shell_path(hook_input.get("cwd", "."))).resolve()
    except (json.JSONDecodeError, KeyError):
        hook_input = {}
        project_dir = Path(".").resolve()

    configure_project_encoding(project_dir)

    trellis_dir = project_dir / ".trellis"
    spec_index_paths = _collect_spec_index_paths(trellis_dir)

    output = StringIO()

    output.write("""<session-context>
Trellis compact SessionStart context. Use it to orient the session; load details on demand.
</session-context>

""")
    output.write(FIRST_REPLY_NOTICE)
    output.write("\n\n")

    output.write("<current-state>\n")
    output.write(_build_compact_current_state(trellis_dir, hook_input, spec_index_paths))
    output.write("\n</current-state>\n\n")

    output.write("<trellis-workflow>\n")
    output.write(_build_workflow_toc(trellis_dir / "workflow.md"))
    output.write("\n</trellis-workflow>\n\n")

    output.write("<guidelines>\n")
    output.write(
        "Task context order for implementation/check: jsonl entries -> `prd.md` -> "
        "`design.md if present` -> `implement.md if present`. Missing optional artifacts "
        "are skipped for lightweight tasks.\n\n"
    )

    if spec_index_paths:
        output.write("## Available indexes (read on demand)\n")
        for p in spec_index_paths:
            output.write(f"- {p}\n")
        output.write("\n")

    output.write(
        "Discover more via: "
        "`python3 ./.trellis/scripts/get_context.py --mode packages`\n"
    )
    output.write("</guidelines>\n\n")

    task_status = _get_task_status(trellis_dir, hook_input)
    output.write(f"<task-status>\n{task_status}\n</task-status>\n\n")

    output.write("""<ready>
Context loaded. Follow <task-status>. Load workflow/spec/task details only when needed.
</ready>""")

    context = output.getvalue()
    result = {
        "suppressOutput": True,
        "systemMessage": f"Trellis context injected ({len(context)} chars)",
        "hookSpecificOutput": {
            "hookEventName": "SessionStart",
            "additionalContext": context,
        },
    }

    print(json.dumps(result, ensure_ascii=False), flush=True)


if __name__ == "__main__":
    main()