Experimental json generator

misc/prices-json-exp.py

@@ -0,0 +1,186 @@
+#! /usr/bin/env python
+
+# Experimental module to generate a JSON version of the .prices file.
+
+# Set to True to allow export of systems that don't have any station data
+emptySystems = True
+# Set to True to allow export of stations that don't have prices
+emptyStations = True
+# Positions should be xferred as whole multiples of this
+posMultiplier = 32
+
+import sqlite3
+import json
+import time
+import collections
+import os
+
+conn = sqlite3.connect("data/TradeDangerous.db")
+
+def collectItemData(db):
+    """
+    Builds a flat, array of item names that serves as a table of items.
+    Station Price Data refers to this table by position in the array.
+    As a result, we also need a mapping for itemID -> tableID
+    """
+
+    items = []      # table of items
+    itemIdx = {}    # mapping from itemID -> position in items
+    for ID, name in db.execute("SELECT i.item_id, i.name FROM Item AS i"):
+        itemIdx[ID] = len(items)
+        items.append(name)
+
+    return items, itemIdx
+
+
+def collectSystems(
+            db,
+            itemIdx,
+            posMult=None,
+            withEmptySystems=False,
+            withStations=True,
+            withEmptyStations=False,
+            withPrices=True
+    ):
+    """
+    Build the System -> Station -> Price data from the supplied DB.
+
+    withEmptySystems:
+        True: include systems with no station data.
+
+    withStations:
+        False: (implies withEmptySystems=True) don't include station data.
+
+    withEmptyStations:
+        True: include stations with no price data.
+
+    withPrices:
+        False: (implies withEmptyStations=True) don't include price data.
+    """
+
+    systems = collections.defaultdict(dict)
+    if not withStations:
+        withEmptySystems = True
+
+    for sysID, sys, posX, posY, posZ in db.execute("""
+            SELECT  sys.system_id, sys.name,
+                    sys.pos_x, sys.pos_y, sys.pos_z
+            FROM  System AS sys
+                    LEFT OUTER JOIN Station
+                        USING (system_id)
+            GROUP  BY 1
+            """):
+        if posMult:
+            posX = int(posX * posMult)
+            posY = int(posY * posMult)
+            posZ = int(posZ * posMult)
+        systemData = {
+                 'pos': [ posX, posY, posZ ],
+        }
+        if withStations:
+            stations = collectStations(
+                    db, itemIdx,
+                    sysID,
+                    withEmptyStations=withEmptyStations,
+                    withPrices=withPrices,
+            )
+            if not stations and not withEmptySystems:
+                continue
+            if stations:
+                systemData['stn'] = stations
+        systems[sys] = systemData
+
+    return systems
+
+
+def collectStations(
+            db,
+            itemIdx,
+            sysID,
+            withEmptyStations=False,
+            withPrices=True
+    ):
+    """
+    Populate a station list for a given system, including price data.
+    """
+    stations = {}
+    if not withPrices:
+        withEmptyStations = True
+    for stnID, name, lsFromStar, lastMod in db.execute("""
+            SELECT  stn.station_id, stn.name, stn.ls_from_star,
+                    MAX(si.modified)
+              FROM  Station AS stn
+                    LEFT OUTER JOIN StationItem si
+                        USING (station_id)
+             WHERE  stn.system_id = ?
+             GROUP  BY 1
+            """, [sysID]):
+        if not lastMod and not withEmptyStations:
+            continue
+        stationData = {
+                'ls':   int(lsFromStar),
+        }
+        if lastMod:
+            stationData['ts'] = lastMod
+            if withPrices:
+                buy, sell = collectPriceData(
+                        db, itemIdx,
+                        stnID,
+                )
+                stationData['buy'] = buy
+                stationData['sell'] = sell
+
+        stations[name] = stationData
+
+    return stations
+
+
+def collectPriceData(db, itemIdx, stnID):
+    """
+    Collect buying and selling data for a given station. Items reference the
+    position in the itemData array.
+    """
+
+    buying, selling = [], []
+
+    for itmID, cr in db.execute("""
+            SELECT  sb.item_id, sb.price
+              FROM  StationBuying AS sb
+             WHERE  station_id = ?
+            """, [stnID]):
+        buying.append([ itemIdx[itmID], cr ])
+
+    for itmID, cr, units, level in db.execute("""
+            SELECT  ss.item_id, ss.price, ss.units, ss.level
+              FROM  StationSelling AS ss
+             WHERE  station_id = ?
+            """, [stnID]):
+        selling.append([ itemIdx[itmID], cr, units, level ])
+
+    return buying, selling
+
+
+itemData, itemIdx = collectItemData(conn)
+sysData = collectSystems(
+        conn, itemIdx,
+        posMult=posMultiplier,
+        withEmptySystems=emptySystems, withEmptyStations=emptyStations
+)
+jsonData = {
+    'src': 'td/json-exp',
+    'posMult': posMultiplier,
+    'time': int(time.time()),
+    'items': itemData,
+    'emptySys': emptySystems,
+    'emptyStn': emptyStations,
+    'sys': sysData,
+}
+
+try:
+    cmdrName = os.environ['CMDR']
+    jsonData['cmdr'] = cmdrName
+except KeyError:
+    pass
+
+print(json.dumps(jsonData, separators=(',',':')))
+