refactor: 重写题目获得逻辑

src/fetch_problem/manager.rs

@@ -0,0 +1,72 @@
+use super::{Problem, ProblemManager};
+use std::fs;
+use regex::{Regex};
+
+impl ProblemManager {
+    pub fn scan() -> Result<ProblemManager, Box<dyn std::error::Error>> {
+        let pattern = Regex::new(r"p(\d{4})_")?;
+        let mut problems = Vec::new();
+        let mod_content = fs::read_to_string("./src/problem/mod.rs")?;
+
+        for i in pattern.captures_iter(&mod_content) {
+            match i.get(1) {
+                None => {}
+                Some(value) => {
+                    match value.as_str().parse::<u32>() {
+                        Ok(id) => {
+                            problems.push(id);
+                        }
+                        Err(_) => {}
+                    }
+                }
+            }
+        }
+
+        Ok(ProblemManager {
+            problem_list: problems
+        })
+    }
+}
+
+impl Problem {
+    pub fn get_filename(&self) -> String {
+        format!("p{}_{}", self.question_id, self.title_slug.replace('-', "_"))
+    }
+
+    pub fn get_file_content(&self) -> Result<String, Box<dyn std::error::Error>> {
+        let template = fs::read_to_string("./template.rs")?;
+
+        let code = self.code_definition
+            .iter()
+            .find(|x| x.value == "rust");
+
+        let code = code.ok_or::<Box<dyn std::error::Error>>(
+            format!("problem {} doesn't have rust version", self.question_id).into()
+        )?;
+
+        let source = template
+            .replace("__PROBLEM_TITLE__", &self.title)
+            .replace("__PROBLEM_ID__", self.question_id.to_string().as_str())
+            .replace(
+                "__PROBLEM_DEFAULT_CODE__",
+                &code.default_code)
+            .replace("__EXTRA_USE__", &parse_extra_use(&code.default_code));
+
+        Ok(source)
+    }
+}
+
+fn parse_extra_use(code: &str) -> String {
+    let mut extra_use_line = String::new();
+    // a linked-list problem
+    if code.contains("pub struct ListNode") {
+        extra_use_line.push_str("\nuse crate::util::linked_list::{ListNode, to_list};")
+    }
+    if code.contains("pub struct TreeNode") {
+        extra_use_line.push_str("\nuse crate::util::tree::{TreeNode, to_tree};")
+    }
+    if code.contains("pub struct Point") {
+        extra_use_line.push_str("\nuse crate::util::point::Point;")
+    }
+    extra_use_line
+}