From 23e2cf726bab815b9753108a7e6da34851c181d2 Mon Sep 17 00:00:00 2001
From: LukasK13 <spam.lukas.klass@gmail.com>
Date: Wed, 8 Apr 2020 13:38:08 +0200
Subject: [PATCH] Create a target from a file

---
 esbo_etc/classes/target/FileTarget.py | 43 +++++++++++++++++++++++++++
 esbo_etc/classes/target/__init__.py   |  1 +
 2 files changed, 44 insertions(+)
 create mode 100644 esbo_etc/classes/target/FileTarget.py

diff --git a/esbo_etc/classes/target/FileTarget.py b/esbo_etc/classes/target/FileTarget.py
new file mode 100644
index 0000000..c44314a
--- /dev/null
+++ b/esbo_etc/classes/target/FileTarget.py
@@ -0,0 +1,43 @@
+from ..target.ATarget import ATarget
+from ..SpectralQty import SpectralQty
+import astropy.units as u
+from astropy.io import ascii
+import re
+
+
+class FileTarget(ATarget):
+    """
+    A class to create a target from a file containing the spectral flux densities
+    """
+
+    def __init__(self, file: str):
+        """
+        Initialize a new target from a file containing the spectral flux density values
+
+        Parameters
+        ----------
+        file : str
+            The file to read the spectral flux density values from. The file needs to provide two columns: wavelength
+            and the corresponding spectral flux density. The format of the file will be guessed by
+            `astropy.io.ascii.read(). If the file doesn't provide units via astropy's enhanced CSV format, the units will
+            be read from the column headers or otherwise assumed to be *nm* and *W / m^2 / nm*.
+        """
+        # Read the file
+        data = ascii.read(file)
+        # Check if units are given
+        if data[data.colnames[0]].unit is None:
+            # Convert values to float
+            data[data.colnames[0]] = list(map(float, data[data.colnames[0]]))
+            data[data.colnames[1]] = list(map(float, data[data.colnames[1]]))
+            # Check if units are given in column headers
+            if all([re.search("\\[.+\\]", x) for x in data.colnames]):
+                # Extract units from headers and apply them on the columns
+                units = [u.Unit(re.findall("(?<=\\[).+(?=\\])", x)[0]) for x in data.colnames]
+                data[data.colnames[0]].unit = units[0]
+                data[data.colnames[1]].unit = units[1]
+            # Use default units
+            else:
+                data[data.colnames[0]].unit = u.nm
+                data[data.colnames[1]].unit = u.W / (u.m ** 2 * u.nm)
+        # Create a spectral quantity from the data and initialize the super class
+        super().__init__(SpectralQty(data[data.colnames[0]].quantity, data[data.colnames[1]].quantity))
diff --git a/esbo_etc/classes/target/__init__.py b/esbo_etc/classes/target/__init__.py
index 0b4b467..b1d8fbf 100644
--- a/esbo_etc/classes/target/__init__.py
+++ b/esbo_etc/classes/target/__init__.py
@@ -1,2 +1,3 @@
 from esbo_etc.classes.target.ATarget import *
 from esbo_etc.classes.target.BlackBodyTarget import *
+from esbo_etc.classes.target.FileTarget import *