updated rule based logic for finding and outputting files

src/resolver.rs

@@ -0,0 +1,193 @@
+use std::path::{Path, PathBuf};
+
+pub struct Rule {
+    pub template_suffix: &'static str,
+    pub active_suffix: &'static str,
+    pub is_exact_match: bool,
+}
+
+pub const RULES: &[Rule] = &[
+    // Exact matches
+    Rule { template_suffix: "compose.yml", active_suffix: "compose.override.yml", is_exact_match: true },
+    Rule { template_suffix: "compose.yaml", active_suffix: "compose.override.yaml", is_exact_match: true },
+    Rule { template_suffix: "docker-compose.yml", active_suffix: "docker-compose.override.yml", is_exact_match: true },
+    Rule { template_suffix: "docker-compose.yaml", active_suffix: "docker-compose.override.yaml", is_exact_match: true },
+    
+    // Pattern matches
+    Rule { template_suffix: ".env.example", active_suffix: ".env", is_exact_match: false },
+    Rule { template_suffix: ".env.template", active_suffix: ".env", is_exact_match: false },
+    Rule { template_suffix: ".example.json", active_suffix: ".json", is_exact_match: false },
+    Rule { template_suffix: ".template.json", active_suffix: ".json", is_exact_match: false },
+    Rule { template_suffix: ".example.yml", active_suffix: ".yml", is_exact_match: false },
+    Rule { template_suffix: ".template.yml", active_suffix: ".yml", is_exact_match: false },
+    Rule { template_suffix: ".example.yaml", active_suffix: ".yaml", is_exact_match: false },
+    Rule { template_suffix: ".template.yaml", active_suffix: ".yaml", is_exact_match: false },
+    Rule { template_suffix: ".example.toml", active_suffix: ".toml", is_exact_match: false },
+    Rule { template_suffix: ".template.toml", active_suffix: ".toml", is_exact_match: false },
+];
+
+pub const DEFAULT_CANDIDATES: &[&str] = &[
+    ".env.example",
+    "compose.yml",
+    "docker-compose.yml",
+    ".env.template",
+    "compose.yaml",
+    "docker-compose.yaml",
+];
+
+/// Helper to automatically determine the output file path based on common naming conventions.
+pub fn determine_output_path(input: &Path) -> PathBuf {
+    let file_name = input.file_name().unwrap_or_default().to_string_lossy();
+
+    for rule in RULES {
+        if rule.is_exact_match {
+            if file_name == rule.template_suffix {
+                return input.with_file_name(rule.active_suffix);
+            }
+        } else {
+            if file_name == rule.template_suffix {
+                return input.with_file_name(rule.active_suffix);
+            } else if let Some(base) = file_name.strip_suffix(rule.template_suffix) {
+                return input.with_file_name(format!("{}{}", base, rule.active_suffix));
+            }
+        }
+    }
+
+    input.with_extension(format!(
+        "{}.out",
+        input.extension().unwrap_or_default().to_string_lossy()
+    ))
+}
+
+/// Discovers common configuration template files in the current directory.
+pub fn find_input_file() -> Option<PathBuf> {
+    // Priority 1: Exact matches for well-known defaults
+    for &name in DEFAULT_CANDIDATES {
+        let path = PathBuf::from(name);
+        if path.exists() {
+            return Some(path);
+        }
+    }
+
+    // Priority 2: Pattern matches
+    if let Ok(entries) = std::fs::read_dir(".") {
+        let mut fallback = None;
+        for entry in entries.flatten() {
+            let name = entry.file_name();
+            let name_str = name.to_string_lossy();
+
+            for rule in RULES {
+                if !rule.is_exact_match && name_str.ends_with(rule.template_suffix) {
+                    if name_str.contains(".env") || name_str.contains("compose") {
+                        return Some(entry.path());
+                    }
+                    if fallback.is_none() {
+                        fallback = Some(entry.path());
+                    }
+                    break;
+                }
+            }
+        }
+        if let Some(path) = fallback {
+            return Some(path);
+        }
+    }
+
+    None
+}
+
+/// Resolves the active and template paths given an input path.
+/// Returns `(active_path, template_path)`.
+pub fn resolve_paths(input: &Path) -> (Option<PathBuf>, Option<PathBuf>) {
+    let file_name = input.file_name().unwrap_or_default().to_string_lossy();
+    
+    // Check if the input matches any known template pattern
+    let mut is_template = false;
+    for rule in RULES {
+        if rule.is_exact_match {
+            if file_name == rule.template_suffix {
+                is_template = true;
+                break;
+            }
+        } else if file_name.ends_with(rule.template_suffix) {
+            is_template = true;
+            break;
+        }
+    }
+
+    // Fallback template detection
+    if !is_template && (file_name.contains(".example") || file_name.contains(".template")) {
+        is_template = true;
+    }
+
+    if is_template {
+        let expected_active = determine_output_path(input);
+        let active = if expected_active.exists() {
+            Some(expected_active)
+        } else {
+            None
+        };
+        (active, Some(input.to_path_buf()))
+    } else {
+        // Input is treated as the active config
+        let active = Some(input.to_path_buf());
+        let mut template = None;
+        
+        // Try to reverse match rules to find a template
+        for rule in RULES {
+            if rule.is_exact_match {
+                if file_name == rule.active_suffix {
+                    let t = input.with_file_name(rule.template_suffix);
+                    if t.exists() {
+                        template = Some(t);
+                        break;
+                    }
+                }
+            } else if file_name.ends_with(rule.active_suffix) {
+                if file_name == rule.active_suffix {
+                    let t = input.with_file_name(rule.template_suffix);
+                    if t.exists() {
+                        template = Some(t);
+                        break;
+                    }
+                } else if let Some(base) = file_name.strip_suffix(rule.active_suffix) {
+                    let t = input.with_file_name(format!("{}{}", base, rule.template_suffix));
+                    if t.exists() {
+                        template = Some(t);
+                        break;
+                    }
+                }
+            }
+        }
+        
+        // Fallback reverse detection
+        if template.is_none() {
+            let possible_templates = [
+                format!("{}.example", file_name),
+                format!("{}.template", file_name),
+            ];
+            for t in possible_templates {
+                let p = input.with_file_name(t);
+                if p.exists() {
+                    template = Some(p);
+                    break;
+                }
+            }
+        }
+
+        (active, template)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_determine_output_path() {
+        assert_eq!(determine_output_path(Path::new(".env.example")), PathBuf::from(".env"));
+        assert_eq!(determine_output_path(Path::new("compose.yml")), PathBuf::from("compose.override.yml"));
+        assert_eq!(determine_output_path(Path::new("config.template.json")), PathBuf::from("config.json"));
+        assert_eq!(determine_output_path(Path::new("config.example")), PathBuf::from("config.example.out"));
+    }
+}