import json

import aiosqlite
from config import DB_PATH

CREATE_GUIDES = """
CREATE TABLE IF NOT EXISTS guides (
    id TEXT PRIMARY KEY,
    topic TEXT NOT NULL,
    format TEXT NOT NULL,
    instructions TEXT NOT NULL DEFAULT '',
    status TEXT NOT NULL DEFAULT 'queued',
    progress TEXT,
    step INTEGER,
    error_msg TEXT,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
)
"""

CREATE_PROGRESS = """
CREATE TABLE IF NOT EXISTS guide_progress (
    guide_id TEXT NOT NULL,
    chapter TEXT NOT NULL,
    created_at TEXT NOT NULL,
    PRIMARY KEY (guide_id, chapter)
)
"""

CREATE_TOPICS = """
CREATE TABLE IF NOT EXISTS topics (
    name TEXT PRIMARY KEY,
    created_at TEXT NOT NULL
)
"""

CREATE_ELEMENTS = """
CREATE TABLE IF NOT EXISTS elements (
    id TEXT PRIMARY KEY,
    topic TEXT NOT NULL,
    title TEXT NOT NULL,
    description TEXT NOT NULL DEFAULT '',
    examples TEXT NOT NULL DEFAULT '[]',
    hints TEXT NOT NULL DEFAULT '[]',
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
)
"""

CREATE_BAUSTEIN_TEXTE = """
CREATE TABLE IF NOT EXISTS baustein_texte (
    topic TEXT NOT NULL,
    baustein TEXT NOT NULL,
    art TEXT NOT NULL,
    md TEXT NOT NULL,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL,
    PRIMARY KEY (topic, baustein, art)
)
"""

CREATE_BAUSTEIN_PROGRESS = """
CREATE TABLE IF NOT EXISTS baustein_progress (
    topic TEXT NOT NULL,
    baustein TEXT NOT NULL,
    gute_antworten INTEGER NOT NULL DEFAULT 0,
    absolviert TEXT,
    verstanden TEXT,
    gemeistert TEXT,
    updated_at TEXT NOT NULL,
    PRIMARY KEY (topic, baustein)
)
"""

_db: aiosqlite.Connection | None = None


async def get_db() -> aiosqlite.Connection:
    global _db
    if _db is None:
        _db = await aiosqlite.connect(DB_PATH)
        _db.row_factory = None
    return _db


async def init_db():
    db = await get_db()
    # WAL übersteht Crashes deutlich besser; busy_timeout fängt kurze Locks ab.
    await db.execute("PRAGMA journal_mode=WAL")
    await db.execute("PRAGMA busy_timeout=5000")
    await db.execute(CREATE_GUIDES)
    await db.execute(CREATE_PROGRESS)
    await db.execute(CREATE_TOPICS)
    await db.execute(CREATE_ELEMENTS)
    await db.execute(CREATE_BAUSTEIN_TEXTE)
    await db.execute(CREATE_BAUSTEIN_PROGRESS)
    try:  # Migration für Bestands-DBs ohne step-Spalte
        await db.execute("ALTER TABLE guides ADD COLUMN step INTEGER")
    except aiosqlite.OperationalError:
        pass
    try:  # Migration für Bestands-DBs ohne verstanden-Spalte (Mastery-Stufe)
        await db.execute("ALTER TABLE baustein_progress ADD COLUMN verstanden TEXT")
    except aiosqlite.OperationalError:
        pass
    try:  # Migration für Bestands-DBs ohne gemeistert-Spalte (Meisterpfad 25)
        await db.execute("ALTER TABLE baustein_progress ADD COLUMN gemeistert TEXT")
    except aiosqlite.OperationalError:
        pass
    # Migration: alte vertiefungen-Tabelle → baustein_texte (Bestand = lange Form, art 'deepdive')
    cursor = await db.execute("SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'vertiefungen'")
    if await cursor.fetchone():
        await db.execute(
            "INSERT OR IGNORE INTO baustein_texte (topic, baustein, art, md, created_at, updated_at) "
            "SELECT topic, baustein, 'deepdive', md, created_at, updated_at FROM vertiefungen"
        )
        await db.execute("DROP TABLE vertiefungen")
    await db.execute(
        "UPDATE guides SET status = 'error', progress = NULL, error_msg = 'Server-Neustart' "
        "WHERE status IN ('queued', 'generating')"
    )
    await db.commit()


async def close_db():
    global _db
    if _db is not None:
        await _db.close()
        _db = None


def _row_to_dict(row, cursor):
    columns = [d[0] for d in cursor.description]
    return dict(zip(columns, row))


async def create_guide(guide: dict) -> dict:
    db = await get_db()
    await db.execute(
        """INSERT INTO guides (id, topic, format, instructions, status, progress, created_at, updated_at)
           VALUES (:id, :topic, :format, :instructions, :status, :progress, :created_at, :updated_at)""",
        guide,
    )
    await db.commit()
    return guide


async def get_guide(guide_id: str) -> dict | None:
    db = await get_db()
    cursor = await db.execute("SELECT * FROM guides WHERE id = ?", (guide_id,))
    row = await cursor.fetchone()
    if row is None:
        return None
    return _row_to_dict(row, cursor)


async def list_guides() -> list[dict]:
    db = await get_db()
    cursor = await db.execute("SELECT * FROM guides ORDER BY created_at DESC")
    rows = await cursor.fetchall()
    return [_row_to_dict(row, cursor) for row in rows]


async def update_guide(guide_id: str, **fields) -> None:
    sets = ", ".join(f"{k} = :{k}" for k in fields)
    fields["id"] = guide_id
    db = await get_db()
    await db.execute(f"UPDATE guides SET {sets} WHERE id = :id", fields)
    await db.commit()


async def delete_guide(guide_id: str) -> bool:
    db = await get_db()
    cursor = await db.execute("DELETE FROM guides WHERE id = ?", (guide_id,))
    await db.commit()
    return cursor.rowcount > 0


# --- Themen ---

async def create_topic(name: str) -> None:
    from datetime import datetime, timezone
    db = await get_db()
    await db.execute(
        "INSERT OR IGNORE INTO topics (name, created_at) VALUES (?, ?)",
        (name, datetime.now(timezone.utc).isoformat()),
    )
    await db.commit()


async def list_topics() -> list[str]:
    db = await get_db()
    cursor = await db.execute("SELECT name FROM topics ORDER BY created_at DESC")
    rows = await cursor.fetchall()
    return [row[0] for row in rows]


async def delete_topic(name: str) -> None:
    db = await get_db()
    await db.execute("DELETE FROM topics WHERE name = ?", (name,))
    await db.commit()


# --- Elemente ---

def _element_row(row, cursor) -> dict:
    el = _row_to_dict(row, cursor)
    el["examples"] = json.loads(el["examples"] or "[]")
    el["hints"] = json.loads(el["hints"] or "[]")
    return el


async def create_element(element: dict) -> dict:
    db = await get_db()
    await db.execute(
        """INSERT INTO elements (id, topic, title, description, examples, hints, created_at, updated_at)
           VALUES (:id, :topic, :title, :description, :examples, :hints, :created_at, :updated_at)""",
        {**element, "examples": json.dumps(element["examples"], ensure_ascii=False),
         "hints": json.dumps(element["hints"], ensure_ascii=False)},
    )
    await db.commit()
    return element


async def list_elements(topic: str) -> list[dict]:
    db = await get_db()
    cursor = await db.execute(
        "SELECT * FROM elements WHERE topic = ? ORDER BY updated_at DESC", (topic,)
    )
    rows = await cursor.fetchall()
    return [_element_row(row, cursor) for row in rows]


async def get_element(element_id: str) -> dict | None:
    db = await get_db()
    cursor = await db.execute("SELECT * FROM elements WHERE id = ?", (element_id,))
    row = await cursor.fetchone()
    if row is None:
        return None
    return _element_row(row, cursor)


async def update_element(element_id: str, **fields) -> None:
    for key in ("examples", "hints"):
        if key in fields:
            fields[key] = json.dumps(fields[key], ensure_ascii=False)
    sets = ", ".join(f"{k} = :{k}" for k in fields)
    fields["id"] = element_id
    db = await get_db()
    await db.execute(f"UPDATE elements SET {sets} WHERE id = :id", fields)
    await db.commit()


async def delete_element(element_id: str) -> bool:
    db = await get_db()
    cursor = await db.execute("DELETE FROM elements WHERE id = ?", (element_id,))
    await db.commit()
    return cursor.rowcount > 0


# --- Kapitel-Fortschritt ---

async def list_progress_all() -> dict[str, set[str]]:
    """Kompletter Kapitel-Fortschritt in einem Query: guide_id → Kapitel-Titel."""
    db = await get_db()
    cursor = await db.execute("SELECT guide_id, chapter FROM guide_progress")
    rows = await cursor.fetchall()
    out: dict[str, set[str]] = {}
    for guide_id, chapter in rows:
        out.setdefault(guide_id, set()).add(chapter)
    return out


async def list_progress(guide_id: str) -> list[str]:
    db = await get_db()
    cursor = await db.execute(
        "SELECT chapter FROM guide_progress WHERE guide_id = ?", (guide_id,)
    )
    rows = await cursor.fetchall()
    return [row[0] for row in rows]


async def set_progress(guide_id: str, chapter: str, done: bool) -> None:
    from datetime import datetime, timezone
    db = await get_db()
    if done:
        await db.execute(
            "INSERT OR IGNORE INTO guide_progress (guide_id, chapter, created_at) VALUES (?, ?, ?)",
            (guide_id, chapter, datetime.now(timezone.utc).isoformat()),
        )
    else:
        await db.execute(
            "DELETE FROM guide_progress WHERE guide_id = ? AND chapter = ?", (guide_id, chapter)
        )
    await db.commit()


async def delete_progress(guide_id: str) -> None:
    db = await get_db()
    await db.execute("DELETE FROM guide_progress WHERE guide_id = ?", (guide_id,))
    await db.commit()


# --- Baustein-Lernen: Vertiefungen + Prüfungs-Fortschritt ---

def _now() -> str:
    from datetime import datetime, timezone
    return datetime.now(timezone.utc).isoformat()


async def get_vertiefung(topic: str, baustein: str, art: str) -> str | None:
    db = await get_db()
    cursor = await db.execute(
        "SELECT md FROM baustein_texte WHERE topic = ? AND baustein = ? AND art = ?",
        (topic, baustein, art),
    )
    row = await cursor.fetchone()
    return row[0] if row else None


async def set_vertiefung(topic: str, baustein: str, art: str, md: str) -> None:
    db = await get_db()
    now = _now()
    await db.execute(
        """INSERT INTO baustein_texte (topic, baustein, art, md, created_at, updated_at)
           VALUES (?, ?, ?, ?, ?, ?)
           ON CONFLICT(topic, baustein, art) DO UPDATE SET md = excluded.md, updated_at = excluded.updated_at""",
        (topic, baustein, art, md, now, now),
    )
    await db.commit()


async def list_vertiefungen(topic: str) -> dict[str, set[str]]:
    """Baustein-Titel → vorhandene Text-Arten ('vertiefung'/'deepdive')."""
    db = await get_db()
    cursor = await db.execute("SELECT baustein, art FROM baustein_texte WHERE topic = ?", (topic,))
    rows = await cursor.fetchall()
    out: dict[str, set[str]] = {}
    for baustein, art in rows:
        out.setdefault(baustein, set()).add(art)
    return out


async def list_baustein_progress(topic: str) -> list[dict]:
    db = await get_db()
    cursor = await db.execute(
        "SELECT baustein, gute_antworten, absolviert, verstanden, gemeistert FROM baustein_progress WHERE topic = ?", (topic,)
    )
    rows = await cursor.fetchall()
    return [{"baustein": b, "gute_antworten": n, "absolviert": a, "verstanden": v, "gemeistert": m} for b, n, a, v, m in rows]


async def set_baustein_score(topic: str, baustein: str, score: int) -> int:
    """Setzt den Score absolut (vom Aufrufer geclampt) und liefert ihn zurück."""
    db = await get_db()
    await db.execute(
        """INSERT INTO baustein_progress (topic, baustein, gute_antworten, updated_at)
           VALUES (?, ?, ?, ?)
           ON CONFLICT(topic, baustein) DO UPDATE SET
               gute_antworten = excluded.gute_antworten, updated_at = excluded.updated_at""",
        (topic, baustein, score, _now()),
    )
    await db.commit()
    return score


async def set_baustein_verstanden(topic: str, baustein: str) -> bool:
    """Markiert verstanden (Mastery); True nur beim ersten Mal. Sticky wie absolviert."""
    db = await get_db()
    now = _now()
    await db.execute(
        "INSERT OR IGNORE INTO baustein_progress (topic, baustein, gute_antworten, updated_at) VALUES (?, ?, 0, ?)",
        (topic, baustein, now),
    )
    cursor = await db.execute(
        "UPDATE baustein_progress SET verstanden = ?, updated_at = ? "
        "WHERE topic = ? AND baustein = ? AND verstanden IS NULL",
        (now, now, topic, baustein),
    )
    await db.commit()
    return cursor.rowcount > 0


async def set_baustein_gemeistert(topic: str, baustein: str) -> bool:
    """Markiert gemeistert (Meisterpfad, Score 25); True nur beim ersten Mal. Sticky."""
    db = await get_db()
    now = _now()
    await db.execute(
        "INSERT OR IGNORE INTO baustein_progress (topic, baustein, gute_antworten, updated_at) VALUES (?, ?, 0, ?)",
        (topic, baustein, now),
    )
    cursor = await db.execute(
        "UPDATE baustein_progress SET gemeistert = ?, updated_at = ? "
        "WHERE topic = ? AND baustein = ? AND gemeistert IS NULL",
        (now, now, topic, baustein),
    )
    await db.commit()
    return cursor.rowcount > 0


async def set_baustein_absolviert(topic: str, baustein: str) -> bool:
    """Markiert absolviert; True nur beim ersten Mal (steuert den Element-Task)."""
    db = await get_db()
    now = _now()
    await db.execute(
        "INSERT OR IGNORE INTO baustein_progress (topic, baustein, gute_antworten, updated_at) VALUES (?, ?, 0, ?)",
        (topic, baustein, now),
    )
    cursor = await db.execute(
        "UPDATE baustein_progress SET absolviert = ?, updated_at = ? "
        "WHERE topic = ? AND baustein = ? AND absolviert IS NULL",
        (now, now, topic, baustein),
    )
    await db.commit()
    return cursor.rowcount > 0


async def list_baustein_absolviert_all() -> dict[str, set[str]]:
    """Alle absolvierten Bausteine in einem Query: topic → Baustein-Titel."""
    db = await get_db()
    cursor = await db.execute(
        "SELECT topic, baustein FROM baustein_progress WHERE absolviert IS NOT NULL"
    )
    rows = await cursor.fetchall()
    out: dict[str, set[str]] = {}
    for topic, baustein in rows:
        out.setdefault(topic, set()).add(baustein)
    return out


async def delete_baustein_daten(topic: str) -> None:
    db = await get_db()
    await db.execute("DELETE FROM baustein_texte WHERE topic = ?", (topic,))
    await db.execute("DELETE FROM baustein_progress WHERE topic = ?", (topic,))
    await db.commit()