var path = require('path'),
    when = require('when'),
    semver = require("semver"),
    fs = require("fs"),
    path = require("path"),
    spawn = require("child_process").spawn,
    buildDirectory = path.resolve(process.cwd(), '.build'),
    distDirectory =  path.resolve(process.cwd(), '.dist'),
    configureGrunt = function (grunt) {

        var cfg = {
            // Common paths to be used by tasks
            paths: {
                adminAssets: './core/client/assets',
                build: buildDirectory,
                nightlyBuild: path.join(buildDirectory, 'nightly'),
                weeklyBuild: path.join(buildDirectory, 'weekly'),
                buildBuild: path.join(buildDirectory, 'build'),
                dist: distDirectory,
                nightlyDist: path.join(distDirectory, 'nightly'),
                weeklyDist: path.join(distDirectory, 'weekly'),
                buildDist: path.join(distDirectory, 'build')
            },
            buildType: 'Build',
            pkg: grunt.file.readJSON('package.json'),

            // JSLint all the things!
            jslint: {
                server: {
                    directives: {
                        // node environment
                        node: true,
                        // browser environment
                        browser: false,
                        // allow dangling underscores in var names
                        nomen: true,
                        // allow to do statements
                        todo: true,
                        // allow unused parameters
                        unparam: true,
                        // don't require use strict pragma
                        sloppy: true,
                        // allow bitwise operators
                        bitwise: true
                    },
                    files: {
                        src: [
                            "*.js",
                            "core/*.js",
                            "core/server/**/*.js"
                        ]
                    }
                },
                client: {
                    directives: {
                        // node environment
                        node: false,
                        // browser environment
                        browser: true,
                        // allow dangling underscores in var names
                        nomen: true,
                        // allow to do statements
                        todo: true,
                         // allow unused parameters
                        unparam: true
                    },
                    files: {
                        src: "core/client/**/*.js"
                    },
                    exclude: [
                        "core/client/assets/**/*.js",
                        "core/client/tpl/**/*.js"
                    ]
                },
                shared: {
                    directives: {
                        // node environment
                        node: true,
                        // browser environment
                        browser: false,
                        // allow dangling underscores in var names
                        nomen: true,
                        // allow to do statements
                        todo: true,
                        // allow unused parameters
                        unparam: true,
                        // don't require use strict pragma
                        sloppy: true
                    },
                    files: {
                        src: [
                            "core/shared/**/*.js"
                        ]
                    },
                    exclude: [
                        "core/shared/vendor/**/*.js"
                    ]
                }
            },

            mochacli: {
                options: {
                    ui: "bdd",
                    reporter: "spec"
                },

                all: {
                    src: ['core/test/unit/**/*_spec.js']
                },

                api: {
                    src: ['core/test/unit/**/api*_spec.js']
                },

                perm: {
                    src: ['core/test/unit/**/permissions_spec.js']
                },

                migrate: {
                    src: [
                        'core/test/unit/**/export_spec.js',
                        'core/test/unit/**/import_spec.js'
                    ]
                }
            },

            // Compile all the SASS!
            sass: {
                admin: {
                    files: {
                        '<%= paths.adminAssets %>/css/screen.css': '<%= paths.adminAssets %>/sass/screen.scss'
                    }
                }
            },

            shell: {
                bourbon: {
                    command: 'bourbon install --path <%= paths.adminAssets %>/sass/modules/'
                }
            },

            handlebars: {
                core: {
                    options: {
                        namespace: "JST",
                        processName: function (filename) {
                            filename = filename.replace('core/client/tpl/', '');
                            return filename.replace('.hbs', '');
                        }
                    },
                    files: {
                        "core/client/tpl/hbs-tpl.js": "core/client/tpl/**/*.hbs"
                    }
                }
            },

            groc: {
                docs: {
                    options: {
                        "out": "./docs/",
                        "glob": [
                            "README.md",
                            "config.js",
                            "index.js",
                            "core/ghost.js",
                            "core/server/**/*.js",
                            "core/shared/**/*.js",
                            "core/client/**/*.js"
                        ],
                        "except": [
                            "!core/**/vendor/**/*.js",
                            "!core/client/tpl/**/*.js"
                        ]
                    }
                }
            },

            watch: {
                handlebars: {
                    files: 'core/client/tpl/**/*.hbs',
                    tasks: ['handlebars']
                },
                sass: {
                    files: '<%= paths.adminAssets %>/sass/**/*',
                    tasks: ['sass:admin']
                }
            },

            copy: {
                nightly: {
                    files: [{
                        expand: true,
                        src: [
                            '**',
                            '!node_modules/**',
                            '!core/server/data/*.db',
                            '!.sass*',
                            '!.af*',
                            '!.git*',
                            '!.groc*',
                            '!.travis.yml'
                        ],
                        dest: "<%= paths.nightlyBuild %>/<%= pkg.version %>/"
                    }]
                },
                weekly: {
                    files: [{
                        expand: true,
                        src: [
                            '**',
                            '!node_modules/**',
                            '!core/server/data/*.db',
                            '!.sass*',
                            '!.af*',
                            '!.git*',
                            '!.groc*',
                            '!.travis.yml'
                        ],
                        dest: "<%= paths.weeklyBuild %>/<%= pkg.version %>/"
                    }]
                },
                build: {
                    files: [{
                        expand: true,
                        src: [
                            '**',
                            '!node_modules/**',
                            '!core/server/data/*.db',
                            '!.sass*',
                            '!.af*',
                            '!.git*',
                            '!.groc*',
                            '!.iml*',
                            '!.travis.yml'
                        ],
                        dest: "<%= paths.buildBuild %>/"
                    }]
                }
            },

            compress: {
                nightly: {
                    options: {
                        archive: "<%= paths.nightlyDist %>/Ghost-Nightly-<%= pkg.version %>.zip"
                    },
                    expand: true,
                    cwd: "<%= paths.nightlyBuild %>/<%= pkg.version %>/",
                    src: ["**"]
                },
                weekly: {
                    options: {
                        archive: "<%= paths.weeklyDist %>/Ghost-Weekly-<%= pkg.version %>.zip"
                    },
                    expand: true,
                    cwd: "<%= paths.weeklyBuild %>/<%= pkg.version %>/",
                    src: ["**"]
                },
                build: {
                    options: {
                        archive: "<%= paths.buildDist %>/Ghost-Build.zip"
                    },
                    expand: true,
                    cwd: "<%= paths.buildBuild %>/",
                    src: ["**"]
                }
            },

            bump: {
                options: {
                    tagName: '%VERSION%',
                    commitMessage: '<%= buildType %> Release %VERSION%',
                    tagMessage: '<%= buildType %> Release %VERSION%',
                    pushTo: "origin build"
                }
            }
        };

        grunt.initConfig(cfg);

        grunt.loadNpmTasks("grunt-jslint");
        grunt.loadNpmTasks("grunt-mocha-cli");
        grunt.loadNpmTasks("grunt-shell");
        grunt.loadNpmTasks("grunt-bump");

        grunt.loadNpmTasks("grunt-contrib-compress");
        grunt.loadNpmTasks("grunt-contrib-copy");
        grunt.loadNpmTasks("grunt-contrib-watch");
        grunt.loadNpmTasks("grunt-contrib-sass");
        grunt.loadNpmTasks("grunt-contrib-handlebars");
        grunt.loadNpmTasks('grunt-groc');

        // Update the package information after changes
        grunt.registerTask('updateCurrentPackageInfo', function () {
            cfg.pkg = grunt.file.readJSON('package.json');
        });

        grunt.registerTask('setCurrentBuildType', function (type) {
            cfg.buildType = type;
        });

        // Prepare the project for development
        // TODO: Git submodule init/update (https://github.com/jaubourg/grunt-update-submodules)?
        grunt.registerTask("init", ["shell:bourbon", "sass:admin", 'handlebars']);

        // Run API tests only
        grunt.registerTask("test-api", ["mochacli:api"]);

        // Run permisisons tests only
        grunt.registerTask("test-p", ["mochacli:perm"]);

        // Run migrations tests only
        grunt.registerTask("test-m", ["mochacli:migrate"]);

        // Run tests and lint code
        grunt.registerTask("validate", ["jslint", "mochacli:all"]);

        // Generate Docs
        grunt.registerTask("docs", ["groc"]);

        /* Generate Changelog
         * - Pulls changelog from git, excluding merges.
         * - Uses first line of commit message. Includes committer name.
         */
        grunt.registerTask("changelog", "Generate changelog from Git", function () {
            // TODO: Break the contents of this task out into a separate module,
            // put on npm. (@cgiffard)

            var done = this.async();

            function git(args, callback, depth) {
                depth = depth || 0;

                if (!depth) {
                    grunt.log.writeln("git " + args.join(" "));
                }

                var buffer = [];
                spawn("git", args, {
                    // We can reasonably assume the gruntfile will be in the root of the repo.
                    cwd : __dirname,

                    stdio : ["ignore", "pipe", process.stderr]

                }).on("exit", function (code) {

                    // Process exited correctly but we got no output.
                    // Spawn again, but make sure we don't spiral out of control.
                    // Hack to work around an apparent node bug.
                    //
                    // Frustratingly, it's impossible to distinguish this
                    // bug from a genuine empty log.

                    if (!buffer.length && code === 0 && depth < 20) {
                        return setImmediate(function () {
                            git(args, callback, depth ? depth + 1 : 1);
                        });
                    }

                    if (code === 0) {
                        return callback(buffer.join(""));
                    }

                    // We failed. Git returned a non-standard exit code.
                    grunt.log.error('Git returned a non-zero exit code.');
                    done(false);

                // Push returned data into the buffer
                }).stdout.on("data", buffer.push.bind(buffer));
            }

            // Crazy function for getting around inconsistencies in tagging
            function sortTags(a, b) {
                a = a.tag;
                b = b.tag;

                // NOTE: Accounting for different tagging method for
                // 0.2.1 and up.

                // If we didn't have this issue I'd just pass rcompare
                // into sort directly. Could be something to think about
                // in future.

                if (semver.rcompare(a, "0.2.0") < 0 ||
                        semver.rcompare(b, "0.2.0") < 0) {

                    return semver.rcompare(a, b);
                }

                a = a.split("-");
                b = b.split("-");

                if (semver.rcompare(a[0], b[0]) !== 0) {
                    return semver.rcompare(a[0], b[0]);
                }

                // Using this janky looking integerising-method
                // because it's faster and doesn't result in NaN, which
                // breaks sorting
                return (+b[1] | 0) - (+a[1] | 0);
            }

            // Gets tags in master branch, sorts them with semver,
            function getTags(callback) {
                git(["show-ref", "--tags"], function (results) {
                    results = results
                        .split(/\n+/)
                        .filter(function (tag) {
                            return tag.length && tag.match(/\/\d+\.\d+/);
                        })
                        .map(function (tag) {
                            return {
                                "tag": tag.split(/tags\//).pop().trim(),
                                "ref": tag.split(/\s+/).shift().trim(),
                            };
                        })
                        .sort(sortTags);

                    callback(results);
                });
            }

            // Parses log to extract commit data.
            function parseLog(data) {
                var commits = [],
                    commitRegex =
                        new RegExp(
                            "\\n*[|\\*\\s]*commit\\s+([a-f0-9]+)" +
                                "\\n[|\\*\\s]*Author:\\s+([^<\\n]+)<([^>\\n]+)>" +
                                "\\n[|\\*\\s]*Date:\\s+([^\\n]+)" +
                                "\\n+[|\\*\\s]*[ ]{4}([^\\n]+)",
                            "ig"
                        );

                // Using String.prototype.replace as a kind of poor-man's substitute
                // for a streaming parser.
                data.replace(
                    commitRegex,
                    function (wholeCommit, hash, author, email, date, message) {

                        // The author name and commit message may have trailing space.
                        author = author.trim();
                        message = message.trim();

                        // Reformat date to make it parse-able by JS
                        date =
                            date.replace(
                                /^(\w+)\s(\w+)\s(\d+)\s([\d\:]+)\s(\d+)\s([\+\-\d]+)$/,
                                "$1, $2 $3 $5 $4 $6"
                            );

                        commits.push({
                            "hash": hash,
                            "author": author,
                            "email": email,
                            "date": date,
                            "parsedDate": new Date(Date.parse(date)),
                            "message": message
                        });

                        return null;
                    }
                );

                return commits;
            }

            // Gets git log for specified range.
            function getLog(to, from, callback) {
                var range = from && to ? from + ".." + to : "",
                    args = [ "log", "master", "--no-color", "--no-merges", "--graph" ];

                if (range) {
                    args.push(range);
                }

                git(args, function (data) {
                    callback(parseLog(data));
                });
            }

            // Run the job
            getTags(function (tags) {
                var logPath = path.join(__dirname, "CHANGELOG.md"),
                    log = fs.createWriteStream(logPath),
                    commitCache = {};

                function processTag(tag, callback) {
                    var buffer = "",
                        peek = tag[1];

                    tag = tag[0];

                    getLog(tag.tag, peek.tag, function (commits) {

                        // Use the comparison with HEAD to remove commits which
                        // haven't been included in a build/release yet.

                        if (tag.tag === "HEAD") {
                            commits.forEach(function (commit) {
                                commitCache[commit.hash] = true;
                            });

                            return callback("");
                        }

                        buffer += "## Release " + tag.tag + "\n";

                        commits = commits
                            .filter(function (commit) {

                                // Get rid of jenkins' release tagging commits
                                // Remove commits we've already spat out
                                return (
                                    commit.author !== "TryGhost-Jenkins" &&
                                    !commitCache[commit.hash]
                                );
                            })
                            .map(function (commit) {
                                buffer += "\n* " + commit.message + " (_" + commit.author + "_)";
                                commitCache[commit.hash] = true;
                            });

                        if (!commits.length) {
                            buffer += "\nNo changes were made in this build.\n";
                        }

                        callback(buffer + "\n");
                    });
                }

                // Get two weeks' worth of tags
                tags.unshift({"tag": "HEAD"});

                tags =
                    tags
                        .slice(0, 14)
                        .map(function (tag, index) {
                        return [
                            tag,
                            tags[index + 1] || tags[index]
                        ];
                    });

                log.write("# Ghost Changelog\n\n");
                log.write("_Showing " + tags.length + " releases._\n");

                when.reduce(tags,
                    function (prev, tag, idx) {
                        return when.promise(function (resolve) {
                            processTag(tag, function (releaseData) {
                                resolve(prev + "\n" + releaseData);
                            });
                        });
                    }, "")
                    .then(function (reducedChangelog) {
                        log.write(reducedChangelog);
                        log.close();
                        done(true);
                    });
            });
        });

        /* Nightly builds
         * - Do our standard build steps (sass, handlebars, etc)
         * - Bump patch version in package.json, commit, tag and push
         * - Generate changelog for the past 14 releases
         * - Copy files to build-folder/#/#{version} directory
         * - Clean out unnecessary files (travis, .git*, .af*, .groc*)
         * - Zip files in build folder to dist-folder/#{version} directory
         */
        grunt.registerTask("nightly", [
            "setCurrentBuildType:Nightly",
            "shell:bourbon",
            "sass:admin",
            "handlebars",
            "bump:build",
            "updateCurrentPackageInfo",
            "changelog",
            "copy:nightly",
            "compress:nightly"
        ]);

        grunt.registerTask("weekly", [
            "setCurrentBuildType:Weekly",
            "shell:bourbon",
            "sass:admin",
            "handlebars",
            "bump:build",
            "updateCurrentPackageInfo",
            "changelog",
            "copy:weekly",
            "compress:weekly"
        ]);

        grunt.registerTask("build", [
            "shell:bourbon",
            "sass:admin",
            "handlebars",
            "changelog",
            "copy:build",
            "compress:build"
        ]);

        // When you just say "grunt"
        grunt.registerTask("default", ['sass:admin', 'handlebars']);
    };

module.exports = configureGrunt;