import {
  createClient,
  QueryResult as VercelQueryResult,
} from "@vercel/postgres";
import { Pool, PoolClient } from "pg";

const isVercel = process.env.VERCEL === "1";

let vercelPool: {
  client: ReturnType<typeof createClient>;
  isConnected: boolean;
} | null = null;
let pgPool: Pool | null = null;

async function getVercelClient() {
  if (!vercelPool) {
    vercelPool = {
      client: createClient(),
      isConnected: false,
    };
  }

  if (!vercelPool.isConnected) {
    try {
      await vercelPool.client.connect();
      vercelPool.isConnected = true;
    } catch (error) {
      console.error("Vercel DB connection error:", error);
      throw error;
    }
  }

  return vercelPool.client;
}

function getClient() {
  if (isVercel) {
    return getVercelClient();
  } else {
    if (!pgPool) {
      const config = {
        host: process.env.POSTGRES_HOST || "db",
        user: process.env.POSTGRES_USER || "postgres",
        password: process.env.POSTGRES_PASSWORD,
        database: process.env.POSTGRES_DATABASE || "openwebui_monitor",
        port: parseInt(process.env.POSTGRES_PORT || "5432"),
        max: 20,
        idleTimeoutMillis: 30000,
        connectionTimeoutMillis: 30000,
        statement_timeout: 30000,
      };

      if (process.env.POSTGRES_URL) {
        pgPool = new Pool({
          connectionString: process.env.POSTGRES_URL,
          ssl: {
            rejectUnauthorized: false,
          },
          max: 20,
          idleTimeoutMillis: 30000,
          connectionTimeoutMillis: 30000,
          statement_timeout: 30000,
        });
      } else {
        pgPool = new Pool(config);
      }

      pgPool.on("error", (err) => {
        console.error("Unexpected error on idle client", err);
        process.exit(-1);
      });
    }
    return pgPool;
  }
}

type CommonQueryResult<T = any> = {
  rows: T[];
  rowCount: number;
};

export async function query<T = any>(
  text: string,
  params?: any[]
): Promise<CommonQueryResult<T>> {
  const client = await getClient();
  const startTime = Date.now();

  if (isVercel) {
    try {
      const result = await (client as ReturnType<typeof createClient>).query({
        text,
        values: params || [],
      });
      return {
        rows: result.rows,
        rowCount: result.rowCount || 0,
      };
    } catch (error) {
      console.error("[DB Query Error]", error);
      if (vercelPool) {
        vercelPool.isConnected = false;
      }
      throw error;
    }
  } else {
    let pgClient;
    try {
      pgClient = await (client as Pool).connect();
      const result = await pgClient.query(text, params);
      return {
        rows: result.rows,
        rowCount: result.rowCount || 0,
      };
    } catch (error) {
      console.error("[DB Query Error]", error);
      console.error(`Query text: ${text}`);
      console.error(`Query params:`, params);
      throw error;
    } finally {
      if (pgClient) {
        pgClient.release();
      }
    }
  }
}

if (typeof window === "undefined") {
  process.on("SIGTERM", async () => {
    console.log("SIGTERM received, closing database connections");
    if (pgPool) {
      await pgPool.end();
    }
    if (vercelPool?.client) {
      await vercelPool.client.end();
      vercelPool.isConnected = false;
    }
  });
}

export { getClient };

export async function ensureTablesExist() {
  try {
    const usersTableExists = await query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_name = 'users'
      );
    `);

    if (!usersTableExists.rows[0].exists) {
      await query(`
        CREATE TABLE IF NOT EXISTS users (
          id TEXT PRIMARY KEY,
          email TEXT NOT NULL,
          name TEXT NOT NULL,
          role TEXT NOT NULL DEFAULT 'user',
          balance DECIMAL(16, 6) NOT NULL DEFAULT 0,
          created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          deleted BOOLEAN DEFAULT FALSE
        );
      `);
    } else {
      try {
        await query(`
          DO $$ 
          BEGIN 
            BEGIN
              ALTER TABLE users 
              ADD COLUMN deleted BOOLEAN DEFAULT FALSE;
            EXCEPTION 
              WHEN duplicate_column THEN NULL;
            END;
          END $$;
        `);
      } catch (error) {
        console.error("Error adding deleted column to users table:", error);
      }
    }

    const modelPricesTableExists = await query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_name = 'model_prices'
      );
    `);

    const defaultInputPrice = parseFloat(
      process.env.DEFAULT_MODEL_INPUT_PRICE || "60"
    );
    const defaultOutputPrice = parseFloat(
      process.env.DEFAULT_MODEL_OUTPUT_PRICE || "60"
    );
    const defaultPerMsgPrice = parseFloat(
      process.env.DEFAULT_MODEL_PER_MSG_PRICE || "-1"
    );

    if (!modelPricesTableExists.rows[0].exists) {
      await query(`
        CREATE TABLE IF NOT EXISTS model_prices (
          id TEXT PRIMARY KEY,
          name TEXT NOT NULL,
          base_model_id TEXT,
          input_price NUMERIC(10, 6) DEFAULT ${defaultInputPrice},
          output_price NUMERIC(10, 6) DEFAULT ${defaultOutputPrice},
          per_msg_price NUMERIC(10, 6) DEFAULT ${defaultPerMsgPrice},
          updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
        );
      `);
    } else {
      try {
        await query(`
          DO $$ 
          BEGIN 
            BEGIN
              ALTER TABLE model_prices 
              ADD COLUMN per_msg_price NUMERIC(10, 6) DEFAULT ${defaultPerMsgPrice};
            EXCEPTION 
              WHEN duplicate_column THEN NULL;
            END;
          END $$;
        `);
      } catch (error) {
        console.error("Error adding per_msg_price column:", error);
      }

      try {
        await query(`
          DO $$ 
          BEGIN 
            BEGIN
              ALTER TABLE model_prices 
              ADD COLUMN base_model_id TEXT;
            EXCEPTION 
              WHEN duplicate_column THEN NULL;
            END;
          END $$;
        `);
      } catch (error) {
        console.error("Error adding base_model_id column:", error);
      }
    }

    const userUsageRecordsTableExists = await query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_name = 'user_usage_records'
      );
    `);

    if (!userUsageRecordsTableExists.rows[0].exists) {
      await query(`
        CREATE TABLE IF NOT EXISTS user_usage_records (
          id SERIAL PRIMARY KEY,
          user_id TEXT NOT NULL,
          nickname VARCHAR(255) NOT NULL,
          use_time TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
          model_name VARCHAR(255) NOT NULL,
          input_tokens INTEGER NOT NULL,
          output_tokens INTEGER NOT NULL,
          cost DECIMAL(10, 4) NOT NULL,
          balance_after DECIMAL(10, 4) NOT NULL,
          FOREIGN KEY (user_id) REFERENCES users(id)
        );
      `);
    }

    console.log("Database tables initialized successfully");
  } catch (error) {
    console.error("Failed to initialize database tables:", error);
    throw error;
  }
}

export async function initDatabase() {
  try {
    await ensureTablesExist();
    console.log("Database initialized successfully");
  } catch (error) {
    console.error("Failed to initialize database:", error);
    throw error;
  }
}

export interface ModelPrice {
  id: string;
  name: string;
  input_price: number;
  output_price: number;
  per_msg_price: number;
  updated_at: Date;
}

export interface UserUsageRecord {
  id: number;
  userId: number;
  nickname: string;
  useTime: Date;
  modelName: string;
  inputTokens: number;
  outputTokens: number;
  cost: number;
  balanceAfter: number;
}

export async function getOrCreateModelPrices(
  models: Array<{ id: string; name: string; base_model_id?: string }>
): Promise<ModelPrice[]> {
  try {
    const defaultInputPrice = parseFloat(
      process.env.DEFAULT_MODEL_INPUT_PRICE || "60"
    );
    const defaultOutputPrice = parseFloat(
      process.env.DEFAULT_MODEL_OUTPUT_PRICE || "60"
    );
    const defaultPerMsgPrice = parseFloat(
      process.env.DEFAULT_MODEL_PER_MSG_PRICE || "-1"
    );

    const modelIds = models.map((m) => m.id);
    const baseModelIds = models.map((m) => m.base_model_id).filter((id) => id);

    const existingModelsResult = await query(
      `SELECT * FROM model_prices WHERE id = ANY($1::text[])`,
      [modelIds]
    );

    const baseModelsResult = await query(
      `SELECT * FROM model_prices WHERE id = ANY($1::text[])`,
      [baseModelIds]
    );

    const existingModels = new Map(
      existingModelsResult.rows.map((row) => [row.id, row])
    );
    const baseModels = new Map(
      baseModelsResult.rows.map((row) => [row.id, row])
    );

    const modelsToUpdate = models.filter((m) => existingModels.has(m.id));
    const missingModels = models.filter((m) => !existingModels.has(m.id));

    if (modelsToUpdate.length > 0) {
      for (const model of modelsToUpdate) {
        await query(`UPDATE model_prices SET name = $2 WHERE id = $1`, [
          model.id,
          model.name,
        ]);
      }
    }

    if (missingModels.length > 0) {
      for (const model of missingModels) {
        const baseModel = model.base_model_id
          ? baseModels.get(model.base_model_id)
          : null;

        await query(
          `INSERT INTO model_prices (id, name, input_price, output_price, per_msg_price)
           VALUES ($1, $2, $3, $4, $5)
           RETURNING *`,
          [
            model.id,
            model.name,
            baseModel?.input_price ?? defaultInputPrice,
            baseModel?.output_price ?? defaultOutputPrice,
            baseModel?.per_msg_price ?? defaultPerMsgPrice,
          ]
        );
      }
    }

    const updatedModelsResult = await query(
      `SELECT * FROM model_prices WHERE id = ANY($1::text[])`,
      [modelIds]
    );

    return updatedModelsResult.rows.map((row) => ({
      id: row.id,
      name: row.name,
      input_price: Number(row.input_price),
      output_price: Number(row.output_price),
      per_msg_price: Number(row.per_msg_price),
      updated_at: row.updated_at,
    }));
  } catch (error) {
    console.error("Error in getOrCreateModelPrices:", error);
    throw error;
  }
}

export async function updateModelPrice(
  id: string,
  input_price: number,
  output_price: number,
  per_msg_price: number
): Promise<ModelPrice | null> {
  try {
    const result = await query(
      `UPDATE model_prices 
       SET 
         input_price = CAST($2 AS NUMERIC(10,6)),
         output_price = CAST($3 AS NUMERIC(10,6)),
         per_msg_price = CAST($4 AS NUMERIC(10,6)),
         updated_at = CURRENT_TIMESTAMP
       WHERE id = $1
       RETURNING *`,
      [id, input_price, output_price, per_msg_price]
    );

    if (result.rows[0]) {
      return {
        id: result.rows[0].id,
        name: result.rows[0].model_name,
        input_price: Number(result.rows[0].input_price),
        output_price: Number(result.rows[0].output_price),
        per_msg_price: Number(result.rows[0].per_msg_price),
        updated_at: result.rows[0].updated_at,
      };
    }
    return null;
  } catch (error) {
    console.error("Error updating model price:", error);
    throw error;
  }
}

export async function updateUserBalance(userId: string, balance: number) {
  try {
    const result = await query(
      `UPDATE users
       SET balance = $2
       WHERE id = $1
       RETURNING id, email, balance`,
      [userId, balance]
    );

    return result.rows[0];
  } catch (error) {
    console.error("Error in updateUserBalance:", error);
    throw error;
  }
}

export const pool = {
  connect: async () => {
    if (isVercel) {
      return {
        query: async (text: string, params?: any[]) => {
          const client = await getVercelClient();
          const result = await client.query({
            text,
            values: params || [],
          });
          return result;
        },
        release: () => {},
      };
    } else {
      return (pgPool || (getClient() as Pool)).connect();
    }
  },
  query: async (text: string, params?: any[]) => {
    if (isVercel) {
      const client = await getVercelClient();
      return client.query({
        text,
        values: params || [],
      });
    } else {
      return (pgPool || (getClient() as Pool)).query(text, params);
    }
  },
  end: async () => {
    if (isVercel) {
      if (vercelPool?.client) {
        await vercelPool.client.end();
        vercelPool.isConnected = false;
      }
    } else if (pgPool) {
      await pgPool.end();
    }
  },
};