refactor: promote project to workspace with macros sub-crate

1 files changed, 212 insertions, 0 deletions

diff --git a/just_template/src/expand.rs b/just_template/src/expand.rs
new file mode 100644
index 0000000..b609113
--- /dev/null
+++ b/just_template/src/expand.rs
@@ -0,0 +1,212 @@
+use std::collections::HashMap;
+
+use just_fmt::snake_case;
+
+use crate::template::Template;
+
+const DISPLAY_BLOCK_BEGIN: &str = "??? >>> ";
+const DISPLAY_BLOCK_END: &str = "??? <<<";
+
+const IMPL_AREA_BEGIN: &str = "@@@ >>> ";
+const IMPL_AREA_END: &str = "@@@ <<<";
+
+const IMPL_BEGIN: &str = ">>>>>>>>>>";
+
+const PARAM_BEGIN: &str = "<<<";
+const PARAM_BEND: &str = ">>>";
+
+impl Template {
+    pub fn expand(mut self) -> Option<String> {
+        // Extract template text
+        let expanded = std::mem::take(&mut self.template_str);
+
+        let (expanded, impl_areas) = read_impl_areas(expanded)?;
+        let expanded = apply_impls(&self, expanded, impl_areas)?;
+        let expanded = apply_display_blocks(&self.params, expanded);
+        let expanded = apply_param(&self, expanded)?;
+        Some(expanded.trim().to_string())
+    }
+}
+
+/// Read all ImplAreas (HashMap<Name, Codes>)
+fn read_impl_areas(content: String) -> Option<(String, HashMap<String, String>)> {
+    let mut striped_content = String::new();
+    let mut impl_areas: HashMap<String, String> = HashMap::new();
+
+    let mut current_area_name = String::default();
+    let mut current_area_codes: Vec<String> = Vec::new();
+
+    for line in content.split("\n") {
+        let trimmed_line = line.trim();
+
+        // Implementation block end
+        if trimmed_line.starts_with(IMPL_AREA_END) {
+            // If the current ImplArea name length is less than 1, it means no block is being matched,
+            // so matching fails, exit early
+            if current_area_name.is_empty() {
+                return None;
+            }
+
+            // Submit Impl Area
+            let name = std::mem::take(&mut current_area_name);
+            impl_areas.insert(name, current_area_codes.join("\n"));
+            current_area_codes.clear();
+            continue;
+        }
+
+        // Implementation block start
+        if trimmed_line.starts_with(IMPL_AREA_BEGIN) {
+            // If the current ImplArea name length is greater than 0, it means we are already inside a block,
+            // since nesting is not allowed, matching fails, exit early
+            if !current_area_name.is_empty() {
+                return None;
+            }
+
+            // Get a snake_case name
+            let snake_name = snake_case!(line.trim_start_matches(IMPL_AREA_BEGIN).trim());
+            current_area_name = snake_name;
+
+            // Continue to next line
+            continue;
+        }
+
+        // During implementation block
+        if !current_area_name.is_empty() {
+            // Add to current block code
+            current_area_codes.push(line.to_string());
+            continue;
+        } else {
+            // Add to remaining content
+            striped_content += "\n";
+            striped_content += line;
+        }
+    }
+
+    Some((striped_content, impl_areas))
+}
+
+/// Apply Template parameters to implementation block areas
+fn apply_impls(
+    template: &Template,
+    content: String,
+    impl_areas: HashMap<String, String>,
+) -> Option<String> {
+    let mut applied_content = String::new();
+
+    let mut impled_areas: HashMap<String, Vec<String>> = HashMap::new();
+    for (impl_area_name, impl_area_template) in impl_areas {
+        // Get user-provided parameters
+        let impl_items = template.impl_params.get(&impl_area_name);
+
+        // No parameters, return early
+        let Some(impl_items) = impl_items else {
+            impled_areas.insert(impl_area_name, Vec::new());
+            continue;
+        };
+
+        let mut impled_area_code_applied = Vec::new();
+
+        // Split items
+        for item in impl_items {
+            // Get base template
+            let mut applied = impl_area_template.clone();
+
+            // Merge global params with arm-specific params for display block check
+            let mut display_params = template.params.clone();
+            for (k, v) in item {
+                display_params.insert(k.clone(), v.clone());
+            }
+            applied = apply_display_blocks(&display_params, applied);
+
+            // Extract parameters
+            for (param_name, param_value) in item {
+                // Apply parameter
+                applied = applied.replace(
+                    &format!("{}{}{}", PARAM_BEGIN, param_name, PARAM_BEND),
+                    param_value,
+                );
+            }
+
+            // Add applied template
+            impled_area_code_applied.push(applied);
+        }
+
+        impled_areas.insert(impl_area_name, impled_area_code_applied);
+    }
+
+    for line in content.split("\n") {
+        let trimmed_line = line.trim();
+
+        // Recognize implementation line
+        if trimmed_line.starts_with(IMPL_BEGIN) {
+            let impl_name = snake_case!(trimmed_line.trim_start_matches(IMPL_BEGIN).trim());
+
+            // Try to get implementation code block
+            let Some(impled_code) = impled_areas.get(&impl_name) else {
+                continue;
+            };
+
+            if !impled_code.is_empty() {
+                applied_content += "\n";
+                applied_content += impled_code.join("\n").as_str();
+            }
+        } else {
+            // Other content directly appended
+            applied_content += "\n";
+            applied_content += line;
+        }
+    }
+
+    Some(applied_content)
+}
+
+/// Process display blocks (`??? >>> name` / `??? <<<`).
+///
+/// If `params` contains a key matching the block name, the block content is
+/// included (with markers removed). Otherwise the entire block is omitted.
+fn apply_display_blocks(params: &HashMap<String, String>, content: String) -> String {
+    let mut result = String::new();
+    let lines: Vec<&str> = content.split("\n").collect();
+    let mut i = 0;
+    let mut first = true;
+
+    while i < lines.len() {
+        let line = lines[i];
+        let trimmed = line.trim();
+
+        if trimmed.starts_with(DISPLAY_BLOCK_BEGIN) {
+            let block_name = trimmed.trim_start_matches(DISPLAY_BLOCK_BEGIN).trim();
+            let show = params.contains_key(block_name);
+            i += 1;
+
+            while i < lines.len() && !lines[i].trim().starts_with(DISPLAY_BLOCK_END) {
+                if show {
+                    if !first {
+                        result += "\n";
+                    }
+                    result += lines[i];
+                    first = false;
+                }
+                i += 1;
+            }
+        } else if !trimmed.starts_with(DISPLAY_BLOCK_END) {
+            if !first {
+                result += "\n";
+            }
+            result += line;
+            first = false;
+        }
+
+        i += 1;
+    }
+
+    result
+}
+
+fn apply_param(template: &Template, content: String) -> Option<String> {
+    let mut content = content;
+    for (k, v) in template.params.iter() {
+        content = content.replace(&format!("{}{}{}", PARAM_BEGIN, k, PARAM_BEND), v);
+    }
+    Some(content)
+}