#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Copilot Session Start Hook - Emit Trellis session-start context.

Microsoft VS Code Agent hooks are in preview and have been documented since
VS Code 1.110 (February 2026). The official documentation
(https://code.visualstudio.com/docs/copilot/customization/hooks) defines
`SessionStart.hookSpecificOutput.additionalContext` as the field used to inject
additional context into the agent's conversation.

This script emits the spec-compliant SessionStart payload. Whether Copilot
actually consumes `additionalContext` depends on the user's installed VS Code
and Copilot versions, which is outside Trellis's control. UserPromptSubmit
breadcrumbs remain available as a per-turn complement.
"""

from __future__ import annotations

import sys

# 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.

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


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")


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("COPILOT_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="copilot")


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="copilot")


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("<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,
        "hookSpecificOutput": {
            "hookEventName": "SessionStart",
            "additionalContext": context,
        },
    }

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


if __name__ == "__main__":
    main()