import asyncpg
import os
import json
from typing import Optional

DATABASE_URL = os.getenv(
    "DATABASE_URL",
    f"postgresql://{os.getenv('POSTGRES_USER', 'postgres')}:{os.getenv('POSTGRES_PASSWORD', 'postgres')}@{os.getenv('POSTGRES_HOST', 'localhost')}:{os.getenv('POSTGRES_PORT', '5432')}/{os.getenv('POSTGRES_DB', 'copykar')}"
)

SCHEMA = """
CREATE TABLE IF NOT EXISTS sources (
    id SERIAL PRIMARY KEY,
    channel_id BIGINT UNIQUE NOT NULL,
    username VARCHAR(255),
    title VARCHAR(255),
    is_active BOOLEAN DEFAULT TRUE,
    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS targets (
    id SERIAL PRIMARY KEY,
    channel_id BIGINT UNIQUE NOT NULL,
    title VARCHAR(255),
    username VARCHAR(255),
    post_interval_min INT DEFAULT 30,
    personality TEXT DEFAULT '',
    custom_footer TEXT DEFAULT '',
    sleep_start_hour INT DEFAULT 0,
    sleep_end_hour INT DEFAULT 0,
    is_sleep_enabled BOOLEAN DEFAULT FALSE,
    last_post_time TIMESTAMPTZ,
    is_active BOOLEAN DEFAULT TRUE,
    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS posts (
    id BIGSERIAL PRIMARY KEY,
    source_channel_id BIGINT NOT NULL,
    source_message_id BIGINT NOT NULL,
    raw_text TEXT,
    media_path TEXT,
    media_type VARCHAR(64),
    content_hash VARCHAR(128),
    tags TEXT[] DEFAULT '{}',
    is_duplicate BOOLEAN DEFAULT FALSE,
    duplicate_of_id BIGINT REFERENCES posts(id) ON DELETE SET NULL,
    similarity_reason TEXT,
    subject VARCHAR(255),
    ai_text TEXT,
    suggested_target_id INT REFERENCES targets(id) ON DELETE SET NULL,
    target_channel_id INT REFERENCES targets(id) ON DELETE SET NULL,
    status VARCHAR(32) DEFAULT 'pending_review',
    published_to JSONB DEFAULT '[]'::jsonb,
    review_message_id BIGINT,
    scheduled_at TIMESTAMPTZ,
    published_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT unique_source_message UNIQUE (source_channel_id, source_message_id)
);

CREATE INDEX IF NOT EXISTS idx_posts_content_hash ON posts(content_hash);
CREATE INDEX IF NOT EXISTS idx_posts_status ON posts(status);
CREATE INDEX IF NOT EXISTS idx_posts_target_status ON posts(target_channel_id, status);
CREATE INDEX IF NOT EXISTS idx_posts_tags ON posts USING GIN (tags);
CREATE INDEX IF NOT EXISTS idx_posts_created_at ON posts(created_at DESC);

CREATE TABLE IF NOT EXISTS settings (
    key VARCHAR(128) PRIMARY KEY,
    value TEXT NOT NULL,
    description TEXT
);

-- Migration safety for existing tables
ALTER TABLE targets ADD COLUMN IF NOT EXISTS personality TEXT DEFAULT '';
ALTER TABLE targets ADD COLUMN IF NOT EXISTS custom_footer TEXT DEFAULT '';
ALTER TABLE targets ADD COLUMN IF NOT EXISTS sleep_start_hour INT DEFAULT 0;
ALTER TABLE targets ADD COLUMN IF NOT EXISTS sleep_end_hour INT DEFAULT 0;
ALTER TABLE targets ADD COLUMN IF NOT EXISTS is_sleep_enabled BOOLEAN DEFAULT FALSE;
ALTER TABLE posts ADD COLUMN IF NOT EXISTS published_to JSONB DEFAULT '[]'::jsonb;
ALTER TABLE posts ADD COLUMN IF NOT EXISTS is_deleted BOOLEAN DEFAULT FALSE;
"""

_pool: Optional[asyncpg.Pool] = None

async def get_db_pool(dsn: str = DATABASE_URL) -> asyncpg.Pool:
    global _pool
    if _pool is None or _pool._closed:
        _pool = await asyncpg.create_pool(dsn=dsn, min_size=2, max_size=10)
    return _pool

async def close_db_pool():
    global _pool
    if _pool is not None and not _pool._closed:
        await _pool.close()
        _pool = None

async def init_db(dsn: str = DATABASE_URL):
    pool = await get_db_pool(dsn)
    async with pool.acquire() as conn:
        await conn.execute(SCHEMA)