# -*- coding: utf-8 -*-
"""Filesystem-backed project context store."""

import json
import os
import re
import secrets
from datetime import datetime
from typing import Optional

from . import gitea_link
from ..knowledge import gitea

SLUG_RE = re.compile(r"^[a-z0-9][a-z0-9-]{0,62}$")


def _context_root() -> str:
    return os.environ.get("MCP_CONTEXT_ROOT", "/data/context")


def _user_root(username: str) -> str:
    path = os.path.join(_context_root(), username, "projects")
    os.makedirs(path, exist_ok=True)
    return path


def _project_dir(username: str, project_id: str) -> str:
    if not SLUG_RE.match(project_id):
        raise ValueError("ID progetto non valido")
    return os.path.join(_user_root(username), project_id)


def _load_meta(username: str, project_id: str) -> tuple[str, dict]:
    proj_dir = _project_dir(username, project_id)
    meta_path = os.path.join(proj_dir, "meta.json")
    if not os.path.isfile(meta_path):
        raise FileNotFoundError("Progetto non trovato")
    meta = json.load(open(meta_path, encoding="utf-8"))
    return meta_path, meta


def _save_meta(meta_path: str, meta: dict) -> None:
    meta["updated_at"] = datetime.now().astimezone().isoformat(timespec="seconds")
    with open(meta_path, "w", encoding="utf-8") as f:
        json.dump(meta, f, ensure_ascii=False, indent=2)


def _apply_gitea_link(
    username: str,
    meta: dict,
    gitea_repo: Optional[str],
    *,
    verify: bool = True,
    seed_from_gitea: bool = False,
) -> dict:
    repo = gitea_link.normalize_gitea_repo(gitea_repo)
    if verify and repo:
        if not gitea.is_configured(username):
            raise RuntimeError(
                "Gitea non configurato per questo utente — impossibile collegare il repository"
            )
        gitea_link.verify_repo_access(username, repo)

    if repo:
        meta["gitea_repo"] = repo
    else:
        meta.pop("gitea_repo", None)

    if seed_from_gitea and repo:
        proj_dir = _project_dir(username, meta["id"])
        ctx_path = os.path.join(proj_dir, "context.md")
        context_md = open(ctx_path, encoding="utf-8").read() if os.path.isfile(ctx_path) else ""
        new_md, changed = gitea_link.seed_context_from_readme(username, repo, context_md)
        if changed:
            with open(ctx_path, "w", encoding="utf-8") as f:
                f.write(new_md)
            meta["gitea_seeded_at"] = datetime.now().astimezone().isoformat(timespec="seconds")

    return meta


def list_projects(username: str, include_archived: bool = False) -> list:
    root = _user_root(username)
    projects = []
    if not os.path.isdir(root):
        return projects
    for name in sorted(os.listdir(root)):
        meta_path = os.path.join(root, name, "meta.json")
        if not os.path.isfile(meta_path):
            continue
        meta = json.load(open(meta_path, encoding="utf-8"))
        if meta.get("archived") and not include_archived:
            continue
        projects.append(meta)
    return projects


def create_project(
    username: str,
    title: str,
    tags: Optional[list[str]] = None,
    gitea_repo: Optional[str] = None,
    seed_from_gitea: bool = False,
) -> dict:
    slug_base = re.sub(r"[^a-z0-9]+", "-", title.lower()).strip("-") or "progetto"
    project_id = slug_base[:40]
    root = _user_root(username)
    while os.path.exists(os.path.join(root, project_id)):
        project_id = f"{slug_base[:32]}-{secrets.token_hex(2)}"
    proj_dir = _project_dir(username, project_id)
    os.makedirs(os.path.join(proj_dir, "sessions"), exist_ok=True)
    os.makedirs(os.path.join(proj_dir, "artifacts"), exist_ok=True)
    now = datetime.now().astimezone().isoformat(timespec="seconds")
    meta = {
        "id": project_id,
        "title": title.strip(),
        "tags": tags or [],
        "status": "active",
        "archived": False,
        "created_at": now,
        "updated_at": now,
    }
    repo = gitea_link.normalize_gitea_repo(gitea_repo)
    if repo:
        meta["gitea_repo"] = repo

    with open(os.path.join(proj_dir, "meta.json"), "w", encoding="utf-8") as f:
        json.dump(meta, f, ensure_ascii=False, indent=2)
    with open(os.path.join(proj_dir, "context.md"), "w", encoding="utf-8") as f:
        f.write(f"# {title.strip()}\n\n")

    if repo:
        meta = _apply_gitea_link(
            username,
            meta,
            repo,
            verify=True,
            seed_from_gitea=seed_from_gitea,
        )
        _save_meta(os.path.join(proj_dir, "meta.json"), meta)

    return meta


def link_project_repo(
    username: str,
    project_id: str,
    gitea_repo: Optional[str] = None,
    seed_from_gitea: bool = False,
) -> dict:
    meta_path, meta = _load_meta(username, project_id)
    meta = _apply_gitea_link(
        username,
        meta,
        gitea_repo,
        verify=bool(gitea_link.normalize_gitea_repo(gitea_repo)),
        seed_from_gitea=seed_from_gitea,
    )
    _save_meta(meta_path, meta)
    return meta


def get_project_context(
    username: str,
    project_id: str,
    session_limit: int = 5,
    include_gitea: bool = True,
) -> dict:
    proj_dir = _project_dir(username, project_id)
    meta_path = os.path.join(proj_dir, "meta.json")
    if not os.path.isfile(meta_path):
        raise FileNotFoundError("Progetto non trovato")
    meta = json.load(open(meta_path, encoding="utf-8"))
    ctx_path = os.path.join(proj_dir, "context.md")
    context_md = open(ctx_path, encoding="utf-8").read() if os.path.isfile(ctx_path) else ""
    sessions_dir = os.path.join(proj_dir, "sessions")
    sessions = []
    if os.path.isdir(sessions_dir):
        files = sorted(os.listdir(sessions_dir), reverse=True)[:session_limit]
        for fname in files:
            path = os.path.join(sessions_dir, fname)
            if os.path.isfile(path):
                sessions.append({"name": fname, "content": open(path, encoding="utf-8").read()})

    result = {"meta": meta, "context_md": context_md, "recent_sessions": sessions}
    gitea_repo = meta.get("gitea_repo")
    if include_gitea and gitea_repo:
        result["gitea"] = gitea_link.project_enrichment(username, gitea_repo)
    return result


def save_context(username: str, project_id: str, content: str, mode: str = "append") -> dict:
    proj_dir = _project_dir(username, project_id)
    meta_path = os.path.join(proj_dir, "meta.json")
    if not os.path.isfile(meta_path):
        raise FileNotFoundError("Progetto non trovato")
    ctx_path = os.path.join(proj_dir, "context.md")
    if mode == "replace":
        text = content
    else:
        existing = open(ctx_path, encoding="utf-8").read() if os.path.isfile(ctx_path) else ""
        text = existing.rstrip() + "\n\n" + content.strip() + "\n"
    with open(ctx_path, "w", encoding="utf-8") as f:
        f.write(text)
    meta = json.load(open(meta_path, encoding="utf-8"))
    _save_meta(meta_path, meta)
    snapshot = datetime.now().strftime("%Y%m%d-%H%M%S") + ".md"
    with open(os.path.join(proj_dir, "sessions", snapshot), "w", encoding="utf-8") as f:
        f.write(content)
    return meta


def archive_project(username: str, project_id: str, archived: bool = True) -> dict:
    meta_path, meta = _load_meta(username, project_id)
    meta["archived"] = archived
    meta["status"] = "archived" if archived else "active"
    _save_meta(meta_path, meta)
    return meta


def list_resources(username: str) -> list:
    resources = []
    for meta in list_projects(username, include_archived=False):
        desc = f"Contesto progetto {meta['id']}"
        if meta.get("gitea_repo"):
            desc += f" (Gitea: {meta['gitea_repo']})"
        resources.append(
            {
                "uri": f"loogle://context/{username}/{meta['id']}",
                "name": meta["title"],
                "description": desc,
                "mimeType": "text/markdown",
            }
        )
    return resources


def read_resource(username: str, uri: str) -> dict:
    prefix = f"loogle://context/{username}/"
    if not uri.startswith(prefix):
        raise FileNotFoundError("Risorsa non trovata")
    project_id = uri[len(prefix):]
    data = get_project_context(username, project_id, session_limit=0, include_gitea=False)
    text = data["context_md"]
    gitea_repo = data["meta"].get("gitea_repo")
    if gitea_repo:
        text = f"<!-- gitea_repo: {gitea_repo} -->\n\n" + text
    return {
        "uri": uri,
        "mimeType": "text/markdown",
        "text": text,
    }