// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use session::Session;
use middle::ty;

use std::env;
use std::fs::{self, File};
use std::path::{Path, PathBuf};

use syntax::{attr};
use syntax::ast::{self, NodeId, DefId};
use syntax::ast_util;
use syntax::codemap::*;
use syntax::parse::token::{self, get_ident, keywords};
use syntax::visit::{self, Visitor};
use syntax::print::pprust::ty_to_string;


use self::span_utils::SpanUtils;

mod span_utils;
mod recorder;

mod dump_csv;

pub struct SaveContext<'l, 'tcx: 'l> {
    sess: &'l Session,
    analysis: &'l ty::CrateAnalysis<'tcx>,
    span_utils: SpanUtils<'l>,
}

pub struct CrateData {
    pub name: String,
    pub number: u32,
}

// Data for any entity in the Rust language. The actual data contained varied
// with the kind of entity being queried. See the nested structs for details.
pub enum Data {
    FunctionData(FunctionData),
    VariableData(VariableData),
}

pub struct FunctionData {
    pub id: NodeId,
    pub name: String,
    pub qualname: String,
    pub declaration: Option<DefId>,
    pub span: Span,
    pub scope: NodeId,
}

pub struct VariableData {
    pub id: NodeId,
    pub name: String,
    pub qualname: String,
    pub span: Span,
    pub scope: NodeId,
    pub value: String,
    pub type_value: String,
}

impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
    pub fn new(sess: &'l Session,
               analysis: &'l ty::CrateAnalysis<'tcx>,
               span_utils: SpanUtils<'l>)
               -> SaveContext<'l, 'tcx> {
        SaveContext {
            sess: sess,
            analysis: analysis,
            span_utils: span_utils,
        }
    }

    // List external crates used by the current crate.
    pub fn get_external_crates(&self) -> Vec<CrateData> {
        let mut result = Vec::new();

        self.sess.cstore.iter_crate_data(|n, cmd| {
            result.push(CrateData { name: cmd.name.clone(), number: n });
        });

        result
    }

    pub fn get_item_data(&self, item: &ast::Item) -> Data {
        match item.node {
            ast::Item_::ItemFn(..) => {
                let name = self.analysis.ty_cx.map.path_to_string(item.id);
                let qualname = format!("::{}", name);
                let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Fn);

                Data::FunctionData(FunctionData {
                    id: item.id,
                    name: name,
                    qualname: qualname,
                    declaration: None,
                    span: sub_span.unwrap(),
                    scope: self.analysis.ty_cx.map.get_parent(item.id),
                })
            }
            ast::ItemStatic(ref typ, mt, ref expr) => {
                let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(item.id));

                // If the variable is immutable, save the initialising expression.
                let (value, keyword) = match mt {
                    ast::MutMutable => (String::from_str("<mutable>"), keywords::Mut),
                    ast::MutImmutable => (self.span_utils.snippet(expr.span), keywords::Static),
                };

                let sub_span = self.span_utils.sub_span_after_keyword(item.span, keyword);

                Data::VariableData(VariableData {
                    id: item.id,
                    name: get_ident(item.ident).to_string(),
                    qualname: qualname,
                    span: sub_span.unwrap(),
                    scope: self.analysis.ty_cx.map.get_parent(item.id),
                    value: value,
                    type_value: ty_to_string(&typ),
                })
            }
            ast::ItemConst(ref typ, ref expr) => {
                let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(item.id));
                let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Const);

                Data::VariableData(VariableData {
                    id: item.id,
                    name: get_ident(item.ident).to_string(),
                    qualname: qualname,
                    span: sub_span.unwrap(),
                    scope: self.analysis.ty_cx.map.get_parent(item.id),
                    value: self.span_utils.snippet(expr.span),
                    type_value: ty_to_string(&typ),
                })
            }
            _ => {
                // FIXME
                unimplemented!();
            }
        }
    }

    pub fn get_data_for_id(&self, _id: &NodeId) -> Data {
        // FIXME
        unimplemented!();
    }
}

// An AST visitor for collecting paths from patterns.
struct PathCollector {
    // The Row field identifies the kind of pattern.
    collected_paths: Vec<(NodeId, ast::Path, ast::Mutability, recorder::Row)>,
}

impl PathCollector {
    fn new() -> PathCollector {
        PathCollector {
            collected_paths: vec![],
        }
    }
}

impl<'v> Visitor<'v> for PathCollector {
    fn visit_pat(&mut self, p: &ast::Pat) {
        if generated_code(p.span) {
            return;
        }

        match p.node {
            ast::PatStruct(ref path, _, _) => {
                self.collected_paths.push((p.id,
                                           path.clone(),
                                           ast::MutMutable,
                                           recorder::StructRef));
            }
            ast::PatEnum(ref path, _) |
            ast::PatQPath(_, ref path) => {
                self.collected_paths.push((p.id, path.clone(), ast::MutMutable, recorder::VarRef));
            }
            ast::PatIdent(bm, ref path1, _) => {
                debug!("PathCollector, visit ident in pat {}: {:?} {:?}",
                       token::get_ident(path1.node),
                       p.span,
                       path1.span);
                let immut = match bm {
                    // Even if the ref is mut, you can't change the ref, only
                    // the data pointed at, so showing the initialising expression
                    // is still worthwhile.
                    ast::BindByRef(_) => ast::MutImmutable,
                    ast::BindByValue(mt) => mt,
                };
                // collect path for either visit_local or visit_arm
                let path = ast_util::ident_to_path(path1.span, path1.node);
                self.collected_paths.push((p.id, path, immut, recorder::VarRef));
            }
            _ => {}
        }
        visit::walk_pat(self, p);
    }
}

#[allow(deprecated)]
pub fn process_crate(sess: &Session,
                     krate: &ast::Crate,
                     analysis: &ty::CrateAnalysis,
                     odir: Option<&Path>) {
    if generated_code(krate.span) {
        return;
    }

    assert!(analysis.glob_map.is_some());
    let cratename = match attr::find_crate_name(&krate.attrs) {
        Some(name) => name.to_string(),
        None => {
            info!("Could not find crate name, using 'unknown_crate'");
            String::from_str("unknown_crate")
        },
    };

    info!("Dumping crate {}", cratename);

    // find a path to dump our data to
    let mut root_path = match env::var_os("DXR_RUST_TEMP_FOLDER") {
        Some(val) => PathBuf::from(val),
        None => match odir {
            Some(val) => val.join("dxr"),
            None => PathBuf::from("dxr-temp"),
        },
    };

    match fs::create_dir_all(&root_path) {
        Err(e) => sess.err(&format!("Could not create directory {}: {}",
                           root_path.display(), e)),
        _ => (),
    }

    {
        let disp = root_path.display();
        info!("Writing output to {}", disp);
    }

    // Create output file.
    let mut out_name = cratename.clone();
    out_name.push_str(".csv");
    root_path.push(&out_name);
    let output_file = match File::create(&root_path) {
        Ok(f) => box f,
        Err(e) => {
            let disp = root_path.display();
            sess.fatal(&format!("Could not open {}: {}", disp, e));
        }
    };
    root_path.pop();

    let mut visitor = dump_csv::DumpCsvVisitor::new(sess, analysis, output_file);

    visitor.dump_crate_info(&cratename[..], krate);
    visit::walk_crate(&mut visitor, krate);
}

// Utility functions for the module.

// Helper function to escape quotes in a string
fn escape(s: String) -> String {
    s.replace("\"", "\"\"")
}

// If the expression is a macro expansion or other generated code, run screaming
// and don't index.
fn generated_code(span: Span) -> bool {
    span.expn_id != NO_EXPANSION || span  == DUMMY_SP
}