diff --git a/src/main/kotlin/me/msoucy/gbat/Main.kt b/src/main/kotlin/me/msoucy/gbat/Main.kt
index eb8e2ff..d643036 100644
--- a/src/main/kotlin/me/msoucy/gbat/Main.kt
+++ b/src/main/kotlin/me/msoucy/gbat/Main.kt
@@ -56,8 +56,8 @@ class GbatArgs(parser: ArgParser) {
 	val not_interesting by parser.adding("--not-interesting", "-N",
 		help="Regular expression to determine which files should not be included in calculations.")
 	val case_sensitive by parser.flagging("Use case sensitive regexps when determining interesting files (default is case-insensitive)")
-	val departed by parser.storing("--departed-file", "-D", help="File listing departed devs, one per line").default<String?>(null)
-	val risk_file by parser.storing("--bus-risk-file", help="File of dev=float lines (e.g. ejorgensen=0.4) with custom bus risks for devs").default<String?>(null)
+	val departed by parser.storing("--departed-file", "-D", help="File listing departed devs, one per line", transform=::File).default<File?>(null)
+	val risk_file by parser.storing("--bus-risk-file", help="File of dev=float lines (e.g. ejorgensen=0.4) with custom bus risks for devs", transform=::File).default<File?>(null)
 	val default_bus_risk by parser.storing("--default-bus-risk", help="Default risk that a dev will be hit by a bus in your analysis timeframe (defaults to 0.1).") { toDouble() }.default(0.1)
 
 	// Multiprocessing options
@@ -66,7 +66,7 @@ class GbatArgs(parser: ArgParser) {
 
 	// Tuning options
 	val risk_threshold by parser.storing("--risk-threshold", help="Threshold past which to summarize risk (defaults to default bus risk cubed)") { toDouble() }.default<Double?>(null)
-	val creation_constant by parser.storing("--knowledge-creation-constant", help="How much knowledge a changed line should create if a new line creates 1 (defaults to 0.1)") {toDouble()}.default<Double?>(null)
+	val creation_constant by parser.storing("--knowledge-creation-constant", help="How much knowledge a changed line should create if a new line creates 1 (defaults to 0.1)") { toDouble() }.default<Double?>(null)
 
 	// Misc options
 	val git_exe by parser.storing("--git-exe", help="Path to the git executable", transform=::validateGit).default("git").addValidator { validateGit(value) }
diff --git a/src/main/kotlin/me/msoucy/gbat/Models.kt b/src/main/kotlin/me/msoucy/gbat/Models.kt
new file mode 100644
index 0000000..b25b28d
--- /dev/null
+++ b/src/main/kotlin/me/msoucy/gbat/Models.kt
@@ -0,0 +1,85 @@
+package me.msoucy.gbat
+
+import java.io.File
+import kotlin.io.forEachLine
+
+class RiskModel(val threshold : Double,
+                val default : Double,
+                val busRiskFile : File?,
+                val departedFile : File?) {
+    val departed = mutableSetOf<String>()
+    val risks = mutableMapOf<String, Double>().withDefault {default}
+
+    init {
+        parseBusRisks()
+        parseDeparted()
+    }
+
+    operator fun get(author : String) : Double {
+        val name = author.trim()
+        if(name.isEmpty()) {
+            return threshold
+        }
+        return risks.getOrPut(name) { default }
+    }
+
+    fun isDeparted(author : String) = author.trim() in departed
+
+    fun jointBusProb(vararg authors : String) =
+        authors.map { this[it] }.reduce { a, b -> a * b }
+
+    fun jointBusProbBelowThreshold(vararg authors : String) =
+        jointBusProb(*authors) <= threshold
+    
+    private fun parseBusRisks() {
+        busRiskFile?.forEachLine { line ->
+            val sline = line.trim()
+            if(sline.isNotEmpty()) {
+                val segments = sline.split("=")
+                val risk = segments.last()
+                val author = segments.dropLast(1).joinToString(separator="=")
+                risks[author] = risk.toDouble()
+            }
+        }
+    }
+    
+    private fun parseDeparted() {
+        departedFile?.forEachLine { line ->
+            val author = line.trim()
+            if(author.isNotEmpty()) {
+                risks[author] = 1.0
+                departed.add(author)
+            }
+        }
+    }
+}
+
+class LineModel() {
+    inner class Line(var num : Int, var text : String)
+    val model = mutableSetOf<Line>()
+
+    fun add(line : Line) {
+        model.onEach { entry ->
+            if(entry.num >= line.num) {
+                entry.num++
+            }
+        }
+        model.add(line)
+    }
+
+    fun del(line : Line) {
+        model.removeIf { it.num == line.num }
+        model.onEach { entry ->
+            if(entry.num > line.num) {
+                entry.num--
+            }
+        }
+    }
+
+    fun change(line : Line) {
+        model.removeIf { it.num == line.num }
+        model.add(line)
+    }
+
+    fun get() = model.sortedBy { it.num }.map { it.text }
+}
\ No newline at end of file