Add YahooFinance module, historical quotes table

lib/tradex/yahoo_finance.ex

@@ -0,0 +1,93 @@
+defmodule Tradex.YahooFinance do
+  @moduledoc """
+  Module to fetch historical stock quotes from Yahoo Finance's v8 API.
+  """
+
+  @yahoo_finance_url "https://query1.finance.yahoo.com/v8/finance/chart/"
+
+  @doc """
+  Fetches historical stock quotes for a given symbol (ticker) within a date range.
+
+  ## Parameters
+  - symbol: The stock symbol (e.g., "ADBE" for Adobe).
+  - start_date: The start date as a `DateTime`.
+  - end_date: The end date as a `DateTime`.
+
+  ## Returns
+  - {:ok, list_of_quotes} on success.
+  - {:error, reason} on failure.
+  """
+  def fetch_historical_quotes(symbol, start_date, end_date) do
+    # Convert dates to Unix timestamps
+    start_unix = DateTime.to_unix(start_date)
+    end_unix = DateTime.to_unix(end_date)
+
+    # Build the URL with query parameters
+    url = "#{@yahoo_finance_url}#{symbol}?period1=#{start_unix}&period2=#{end_unix}&interval=1d"
+
+    # Make the HTTP GET request
+    case HTTPoison.get(url) do
+      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+        # Parse the JSON response
+        parse_json(body)
+
+      {:ok, %HTTPoison.Response{status_code: status_code}} ->
+        {:error, "Failed to fetch data. Status code: #{status_code}"}
+
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
+  @doc """
+  Parses the JSON response from Yahoo Finance's v8 API into a list of maps.
+
+  ## Parameters
+  - json_data: The JSON data as a string.
+
+  ## Returns
+  - {:ok, list_of_quotes} if the JSON is valid.
+  - {:error, reason} if the JSON is invalid or an error occurs.
+  """
+  defp parse_json(json_data) do
+    case Jason.decode(json_data) do
+      {:ok,
+       %{
+         "chart" => %{
+           "result" => [
+             %{
+               "timestamp" => timestamps,
+               "indicators" => %{
+                 "quote" => [%{"open" => opens, "high" => highs, "low" => lows, "close" => closes, "volume" => volumes}],
+                 "adjclose" => [%{"adjclose" => adj_closes}]
+               }
+             }
+           ]
+         }
+       }} ->
+        # Combine the data into a list of maps
+        quotes =
+          [timestamps, opens, highs, lows, closes, adj_closes, volumes]
+          |> Enum.zip()
+          |> Enum.map(fn {timestamp, open, high, low, close, adj_close, volume} ->
+            %{
+              date: DateTime.from_unix!(timestamp),
+              open: open,
+              high: high,
+              low: low,
+              close: close,
+              adj_close: adj_close,
+              volume: volume
+            }
+          end)
+
+        {:ok, quotes}
+
+      {:ok, _} ->
+        {:error, "No data found in the response"}
+
+      {:error, reason} ->
+        {:error, "Failed to parse JSON response: #{reason}"}
+    end
+  end
+end