/*******************************************************************************
TODO source code analyzer for Coedit projects/files

## Format: 

`` 
// TODO [fields] : text
``

- TODO/FIXME: used to detect that the comment is a "TODO" comment. The keyword is not
case sensitive.

- fields: an optional list of property with a format similar to the execution argument 
of a program: `-<char x><property for char x>-<char y><property for char y>`.
possible fields include:
    - c: TODO category, e.g: _-cserialization_, _-cpersistence_, _ -cerrorhandling_.
    - a: TODO assignee, e.g: _-aMisterFreeze_, _-aMadameMichou_, _-aJhonSmith_.
    - p: TODO priority, eg: _-p8_, _-p0_.
    - s: TODO status, e.g _-sPartiallyFixed_, _-sDone_.
  
- text: the literal message, e.g:  "set this property as const() to set it read only".

## Examples:

``// TODO: set this property as const() to make it read-only.``

``// TODO-cfeature: save this property in the inifile.``

``// TODO-cannnotations-p8: annotate the members of the module with @safe and if possible nothrow.``

``// FIXME-p8: This won't work if all the flags are OR-ed.``

## Widget-to-tool IPC:

The widget calls the tool with a file list as argument and reads the process
output on exit. The widget expects to find some _TODO items_ in _LFM_ format, 
according to the classes declarations of TTodoItems (the collection container) 
and TTodoItem(the collection item).

********************************************************************************/
module cetodo;

// std
import std.stdio, std.getopt, std.string;
import std.array, std.conv, std.traits;
import std.file, std.path, std.range;
// libdparse
import std.d.lexer;

/// Encapsulates the fields of a _TODO comment_.
private struct TodoItem 
{
    /** 
     * Enumerates the possible fields of _a TODO comment_. 
     * They must match the published member of the widget-side class TTodoItem.
     */
    private enum TodoField {filename, line, text, category, assignee, priority, status}
    private string[TodoField] fFields;
     
    /**
     * Constructs a TODO item with its fields.
     * Params:
     * fname = the file where the _TODO comment_ is located. mandatory.
     * line = the line where the _TODO comment_ is located. mandatory.
     * text = the _TODO comment_ main text. mandatory.
     * cat = the _TODO comment_ category, optional.
     * ass = the _TODO comment_ assignee, optional.
     * prior = the _TODO comment_ priority, as an integer litteral, optional.
     * status = the _TODO comment_ status, optional.
     */
    @safe public this(string fname, string line, string text, string cat = "",  string ass = "", string prior = "", string status = "")
    {   
        // line and fname must really be valid
        if (!fname.exists) throw new Exception("TodoItem exception, the file name is invalid");
        try auto l = to!long(line);
        catch(Exception e) throw new Exception("TodoItem exception, the line number is invalid");
        
        // priority must be convertible to int
        if (prior.length) try auto i = to!long(prior);
        catch(Exception e) prior = "";
              
        fFields[TodoField.filename] = fname.idup;
        fFields[TodoField.line]     = line.idup;
        fFields[TodoField.text]     = text.idup;
        fFields[TodoField.category] = cat.idup;
        fFields[TodoField.assignee] = ass.idup;
        fFields[TodoField.priority] = prior.idup;
        fFields[TodoField.status]   = status.idup;
    }
    
    /**
     * The item writes itself as a TCollectionItem.
     * Params:
     * LfmString = the string containing the LFM script.
     */
    @safe public void serialize(ref string LfmString)
    {
        LfmString  ~= "  \r\n    item\r\n";
        foreach(member; EnumMembers!TodoField)
            if (fFields[member].length)
                LfmString  ~= format("      %s = '%s'\r\n", to!string(member), fFields[member]);   
        LfmString  ~= "    end";
    }
}

private alias TodoItems = TodoItem * [];

/**
 * Application main procedure.
 * Params:
 * args = a list of files to analyze. 
 * Called each time a document is focused. Args is set using:
 * - the symbolic string `<CFF>` (current file is not in a project).
 * - the symbolic string `<CPFS>` (current file is in a project).
 */
void main(string[] args)
{
    string[] files = args[1..$];
    string LfmString;
    TodoItems todoItems;
   
    foreach(f; files)
    {
        if (!f.exists) continue;
        
        // load and parse the file
        auto src = cast(ubyte[]) read(f, size_t.max);
        auto config = LexerConfig(f, StringBehavior.source);
        StringCache cache = StringCache(StringCache.defaultBucketCount);
        auto lexer = DLexer(src, config, &cache);
        
        // analyze the tokens
        foreach(tok; lexer) token2TodoItem(tok, f, todoItems);                     
    }
    
    // serialize the items using the pascal component streaming text format
    foreach(todoItem; todoItems) todoItem.serialize(LfmString);
       
    //TODO: NEVER call writeln() in this program otherwise the widget cant interpret the output as LFM
       
    // the widget has the LFM script in the output
    if (LfmString.length) writefln("object TTodoItems\r\n  items = <%s>\r\nend\r\n", LfmString);
}

/// Try to transforms a Token into a a TODO item
@safe private void token2TodoItem(const(Token) atok, string fname,  ref TodoItems todoItems)
{
    if (atok.type != (tok!"comment")) 
        return;
    auto text = atok.text.strip;
    if (text.length < 3) 
        return;
    if (text[1] == '*' || text[1] == '+' || text[2] == '/')
        return; 
        
    text = text[2..$];
    string identifier;
    bool isTodoComment;
    size_t pos;

    // "TODO" 
    while (true) {
        if (pos == text.length) break; 
        if (identifier.length > 3) {
            auto upIdent = identifier.strip.toUpper;  
            if (upIdent == "TODO" || upIdent == "FIXME"){
                isTodoComment = true;
                text = text[pos..$];
                break;
            }
        } 
        identifier ~= text[pos++]; 
    }
    if (!isTodoComment) return;
    
    //fields : text
    identifier = identifier.init;
    auto fc = text.split(':');
    if (fc.length < 2) return;
    auto raw_fields  = fc[0];
    auto raw_content = fc[1..$];
    
    // fields
    string a,c,p,s;
    foreach(field; raw_fields.split('-')) {
        if (field.length < 2) continue;
        switch (field[0]) {
            default: break;
            case 'a': case 'A': 
                a = field[1..$].strip; 
                break;
            case 'c': case 'C': 
                c = field[1..$].strip; 
                break;
            case 'p': case 'P': 
                p = field[1..$].strip; 
                break;
            case 's': case 'S': 
                s = field[1..$].strip; 
                break;
        }
    }
    
    // content, must exists.
    string content = raw_content.join.strip;
    if (!content.length) return;
    
    // item
    todoItems ~= new TodoItem(fname, to!string(atok.line), content, c, a, p, s);
}

// samples for testing the program as a runnable module with <CFF>

// fixme-p8: fixme also handled
// TODO-cINVALID_because_no_content:              
// TODO: set this property as const() to set it read only.
// TODO-cfeature-sDone: save this property in the inifile.
// TODO-cannnotations-p8: annotates the member of the module as @safe and if possible nothrow.
// TODO-cfeature-sDone: save this property in the inifile.