var sqlite = require('sqlite3').verbose();
var async = require('async');

var config = require('./config.js').config;
var helper = require('./helper.js');

var db = new sqlite.Database(config.dbPath);

// Function to get a user record by the username and password
// Returns SQL row for that user
exports.getUser = function(username, password, cb) {
    db.get('SELECT salt FROM users WHERE username = ?', username, function(err, row) {
        var hash = helper.hashPassword(password, row.salt);
        db.get('SELECT username, id, displayName, createDate \
            FROM users WHERE username = ? AND password = ?',
            username, hash, function(err, row) {
                cb(row);
        });
    });
}

// Function to get a user record by id, does not validate user password
// Returns SQL row for that user
exports.getUserById = function(id, cb) {
    db.get('SELECT username, id, displayName, createDate \
        FROM users WHERE id = ?', id, function(err, row) {
            cb(row);
    });
}

// Function to get the latest regenerate date
// Returns a epoch time in seconds
exports.getLastRegenerateDate = function(cb) {
    db.get('SELECT MAX(lastGenerateDate) as date FROM ( \
        SELECT lastGenerateDate FROM posts \
        UNION \
        SELECT lastGenerateDate FROM photos \
        UNION \
        SELECT lastGenerateDate FROM galleries);',
        function(err, row) {
            cb(row);
    });
}

// Function to get the latest upload date
// Returns a epoch time in seconds
exports.getLastUploadDate = function(cb) {
    db.get('SELECT MAX(lastUpload) as date FROM ( \
        SELECT lastUpload FROM posts \
        UNION \
        SELECT lastUpload FROM photos \
        UNION \
        SELECT lastUpload FROM galleries);',
        function(err, row) {
            cb(row);
    });
}

// Function to get a count of current posts
// Returns count of posts
exports.countPosts = function(cb) {
    db.get('SELECT count(id) as count FROM posts;', function(err, count) {
        cb(count.count);
    });
}

// Function to get a count of current galleries
// Returns count of galleries
exports.countGalleries = function(cb) {
    db.get('SELECT count(id) as count FROM galleries;', function(err, count) {
        cb(count.count);
    });
}

// Function to get a count of current categories
// Returns count of categories
exports.countCategories = function(cb) {
    db.get('SELECT count(id) as count FROM categories;', function(err, count) {
        cb(count.count);
    });
}

// Function to get a count of current photos
// Returns count of tags
exports.countPhotos = function(cb) {
    db.get('SELECT count(id) as count FROM photos;', function(err, count) {
        cb(count.count);
    });
}

// Function to get a count of current tags
// Returns count of tags
exports.countTags = function(cb) {
    db.get('SELECT count(id) as count FROM tags;', function(err, count) {
        cb(count.count);
    });
}

// Function to get all categories including their ID and descriptions
// Returns array of rows of categories
exports.listCategories = function(cb) {
    db.all('SELECT * FROM CATEGORIES', function(err, rows) {
        cb(rows);
    });
}

// Function to get a list of posts of a certain count and starting at an offset
// Returns a list of post objects
exports.listPosts = function(count, start, cb) {
    db.all('SELECT * FROM posts ORDER BY postDate DESC, title ASC \
        LIMIT '+count+' OFFSET '+start+';',
        function(err, posts) {
            console.log(err);
            cb(posts);
        });
}

// Function to get a list of photos of a certain count and starting at an offset
// Returns a list of photo objects
exports.listPhotos = function(count, start, cb) {
    db.all('SELECT * FROM photos ORDER BY photoDate DESC, title ASC \
        LIMIT '+count+' OFFSET '+start+';',
        function(err, photos) {
            console.log(err);
            cb(photos);
        });
}

// NON-EXPORTED function to create a category if it does not exist
// Returns a row of category information
var getOrCreateCategory = function(name, cb) {
    db.get('SELECT * FROM categories WHERE name = "'+name+'";', function(err, row) {
        if (!err && row) {
            console.log('Category '+name+' exists.');
            cb(row);
        } else {
            console.log('Category '+name+' does not exist. Creating...');
            epoch = helper.dateToEpoch(new Date());
            db.run('INSERT INTO categories (\
                name, slug, createDate \
                ) VALUES (\
                "'+name+'", \
                "'+helper.makeSlug(name)+'", \
                '+epoch+');',
                function(err, row) {
                    if (err) {
                        console.log(err);
                    }
                    else {
                        console.log('Category '+name+' created.');
                        db.get('SELECT * FROM categories WHERE name = "'+name+'";',
                        function(err, row){
                            cb(row);
                        })
                    }

                })
        }
    })
}

// Function to set a category for a post given a post id and a category name
// Returns error code
exports.setPostCategory = function(postId, categoryName, cb) {
    console.log('Setting post '+postId+' category to '+categoryName);
    getOrCreateCategory(categoryName, function(category) {
        db.get('SELECT categoryId FROM categoryPosts \
            WHERE postId = '+postId+';',
            function(err, row) {
                if (row) {
                    console.log('Post '+postId+' has assigned category of '+row.categoryId);
                    if (row.categoryId == category.id) {
                        console.log('Current post category is the same as new post category, no update necessary.');
                        cb(null);
                    } else {
                        console.log("Current post category ("+row.categoryId+") doesn't match new category ("+category.id+"), updating record.");
                        db.run('UPDATE categoryPosts SET \
                            categoryId = '+category.id+' \
                            WHERE postId = '+postId+';',
                            function(err) {
                                if (err) {
                                    console.log(err);
                                }
                                else {
                                    console.log("Category updated.");
                                    cb(null);
                                }
                            });
                    }
                } else {
                    console.log('Post '+postId+' has no category assigned. Inserting record.');
                    db.run('INSERT INTO categoryPosts (postId, categoryId) VALUES ('+postId+', '+category.id+');',
                        function(err) {
                            if (err) {
                                console.log(err);
                            }
                            else {
                                console.log('Post '+postId+' assigned to category '+category.id);
                                    cb(null);
                            }
                    });
                }

            })

    });

}

// Function to create a new post
// Returns the post id
exports.createPost = function(title, slug, markdown, postDate, updatedDate,
    createDate, cb) {
    db.run('INSERT INTO posts (\
            title, \
            slug, \
            markdown, \
            postDate, \
            createDate, \
            updatedDate, \
            lastGenerateDate, \
            lastUpload) \
            VALUES (\
            "'+title+'", \
            "'+slug+'", \
            "'+markdown+'", \
            "'+postDate+'", \
            "'+createDate+'", \
            "'+updatedDate+'", \
            (strftime("%s","1900-01-01 00:00")*1000), \
            (strftime("%s","1900-01-01 00:00")*1000));',
        function(err, row) {
            if (err) console.log(err);
            db.get('SELECT * FROM posts WHERE title = "'+title+'" AND createDate = '+createDate+';', function(err, row){
                cb(err, row);
            })
        });
}

// Function to update an existing post record
// Returns the post object
exports.updatePost = function(id, title, slug, markdown, postDate, cb) {
    console.log("updatePost called.");
    db.run('UPDATE posts SET \
        title = "'+title+'", \
        slug = "'+slug+'", \
        markdown = "'+markdown+'", \
        postDate = '+helper.dateToEpoch(postDate)+', \
        updatedDate = '+helper.dateToEpoch(new Date())+' \
        WHERE id = '+id+';',
        function(err) {
            console.log('updatePost UPDATE result: '+err);
            db.get('SELECT * FROM posts WHERE id = '+id+';', function(err, row) {
                console.log('updatePost SELECT result: ' + err);
                cb(row);
            });
        });
}

// Function to get a post record by the id of the post
// Returns the post record
exports.getPostById = function(id, cb) {
    db.get('SELECT * FROM posts WHERE id = ?', id, function(err, row) {
        cb(row);
    });
}

// Function to get a category record given a post id
// Returns the first category record associated with the post.
exports.getPostCategory = function(id, cb) {
    db.get('SELECT * FROM categories WHERE id = (\
            SELECT categoryId FROM categoryPosts WHERE postId = '+id+');',
        function(err, row) {
            if (err) {
                console.log(err);
            }
            if (row) {
                console.log('Post '+id+' category is '+row.name);
                cb(row);
            }
            else {
                cb(null);
            }

        });
}

// Function to get record of a tag, inserting it if required.
// Inputs are a tag name and a callback.
// Returns the created tag record.
var getOrCreateTag = function(tag, cb) {
    var slug = helper.makeSlug(tag);
    db.get('SELECT * from tags WHERE slug = "'+slug+'" LIMIT 1;', function(err, row) {
        if (err) {
            console.log(err);
        }
        if (row) {
            console.log(slug+' tag exists');
            cb(row);
        }
        else {
            db.run('INSERT INTO tags (name, slug, createDate) \
                VALUES ("'+tag+'", "'+slug+'", '+ helper.dateToEpoch(new Date()) +');',
                function(err, id) {
                    if (!err) {
                        console.log(slug+' tag created');
                        db.get('SELECT * FROM tags WHERE slug = "'+slug+'" LIMIT 1;',
                            function (err, row) {
                                if (err) console.log(err);
                                if (row) cb(row);
                        });
                    };
                });
        }
    })
}

exports.getOrCreateTag = getOrCreateTag;


// Function to tag a post with a list of tag names
// Inputs: Post ID, List of Tag names
// Does not return.
exports.tagPost = function (postId, tags) {

    console.log('Deleting old tags');
    db.run('DELETE FROM postTags WHERE postId = '+postId+';',
        function(err) {
            console.log('Old tags deleted');
            for (var i = 0, size = tags.length; i < size; i++) {
                getOrCreateTag(tags[i], function(row) {
                    db.run('INSERT INTO postTags (postId, tagId) \
                        VALUES ('+postId+', '+row.id+');',
                        function(err) {
                            if (err) {
                                console.log(err);
                            }
                            else {
                                console.log('Post '+postId+' tagged as '+row.name);
                            }
                        });
                });

            }
    });
}


// Function to get tag ids associated with a particular post id
// Inputs: Post ID
// Returns: Records associated with tags of that post id
var getPostTags = function (postId, cb) {
    db.all('SELECT tagId FROM postTags WHERE postId = '+postId+';',
        function(err, rows) {
            if (err) {
                console.log(err);
            }
            else {
                var tagList = [];
                for (row in rows) {
                    tagList.push(rows[row].tagId);
                }
                tagList = tagList.join(', ');
                console.log('Tag ids for '+postId+': '+tagList);
                db.all('SELECT * FROM tags WHERE id IN ('+tagList+');',
                    function(err, rows) {
                        if (err) {
                            console.log(err);
                        }
                        else {
                            cb(rows);
                        }
                })
            }
    })
}

exports.getPostTags = getPostTags;


// Function that returns all the post tags as a space separated string.
// Inputs: Post ID, callback function.
// Returns: callback of string with all tags separated by spaces.
var getPostTagsAsString = function(postId, cb) {
    getPostTags(postId, function(tags) {
        var str = false;
        for (tag in tags) {
            if (!str) {
                str = tags[tag].name;
            }
            else {
                str = str + ' ' + tags[tag].name;
            }
        }
        console.log("Tags for "+postId+": "+str);
        cb(str);
    })
}

exports.getPostTagsAsString = getPostTagsAsString;


// Function to tag a photo with a list of tag names
// Inputs: Photo ID, List of Tag names
// Does not return.
exports.tagPhoto = function (photoId, tags) {

    console.log('Deleting old tags');
    db.run('DELETE FROM photoTags WHERE photoId = '+photoId+';',
        function(err) {
            console.log('Old tags deleted');
            for (var i = 0, size = tags.length; i < size; i++) {
                getOrCreateTag(tags[i], function(row) {
                    db.run('INSERT INTO photoTags (photoId, tagId) \
                        VALUES ('+photoId+', '+row.id+');',
                        function(err) {
                            if (err) {
                                console.log(err);
                            }
                            else {
                                console.log('Photo '+photoId+' tagged as '+row.name);
                            }
                        });
                });

            }
    });
}


// Function to get tag ids associated with a particular photo id
// Inputs: Photo ID
// Returns: Records associated with tags of that photo id
var getPhotoTags = function (photoId, cb) {
    db.all('SELECT tagId FROM photoTags WHERE photoId = '+photoId+';',
        function(err, rows) {
            if (err) {
                console.log(err);
            }
            else {
                var tagList = [];
                for (row in rows) {
                    tagList.push(rows[row].tagId);
                }
                tagList = tagList.join(', ');
                console.log('Tag ids for photo '+photoId+': '+tagList);
                db.all('SELECT * FROM tags WHERE id IN ('+tagList+');',
                    function(err, rows) {
                        if (err) {
                            console.log(err);
                        }
                        else {
                            cb(rows);
                        }
                })
            }
    })
}

exports.getPhotoTags = getPhotoTags;


// Function that returns all the photo tags as a space separated string.
// Inputs: Photo ID, callback function.
// Returns: callback of string with all tags separated by spaces.
var getPhotoTagsAsString = function(photoId, cb) {
    getPhotoTags(photoId, function(tags) {
        var str = false;
        for (tag in tags) {
            if (!str) {
                str = tags[tag].name;
            }
            else {
                str = str + ' ' + tags[tag].name;
            }
        }
        console.log("Tags for photo "+photoId+": "+str);
        cb(str);
    })
}

exports.getPhotoTagsAsString = getPhotoTagsAsString;

// Function to get a photo record by the id of the photo
// Returns the photo record
exports.getPhotoById = function(id, cb) {
    db.get('SELECT * FROM photos WHERE id = ?', id, function(err, row) {
        if (err) console.log(err);
        cb(row);
    });
}

// Function to create a new photo
// Returns the photo id
exports.createPhoto = function(title, slug, markdown, extension, mimetype, photoDate, updatedDate,
    createDate, path, cb) {
    console.log('Creating new photo: '+slug);
    db.run('INSERT INTO photos (\
            title, \
            slug, \
            description, \
            path, \
            extension, \
            mimetype, \
            photoDate, \
            createDate, \
            updatedDate, \
            lastGenerateDate, \
            lastUpload) \
            VALUES (\
            "'+title+'", \
            "'+slug+'", \
            "'+markdown+'", \
            "'+path+'", \
            "'+extension+'", \
            "'+mimetype+'", \
            "'+photoDate+'", \
            "'+createDate+'", \
            "'+updatedDate+'", \
            (strftime("%s","1900-01-01 00:00")*1000), \
            (strftime("%s","1900-01-01 00:00")*1000));',
        function(err, row) {
            if (!err) {
                console.log('Photo '+slug+' created.');
            }
            else {
                console.log('Error: '+err);
            }
            db.get('SELECT * FROM photos WHERE title = "'+title+'" AND createDate = '+createDate+';', function(err, row){
                if (err) console.log(err);
                cb(err, row);
            })
        });
}

// Function to update an existing post record
// Returns the post object
exports.updatePhoto = function(id, title, slug, markdown, photoDate, cb) {
    console.log("updatePost called.");
    db.run('UPDATE photos SET \
        title = "'+title+'", \
        slug = "'+slug+'", \
        description = "'+markdown+'", \
        photoDate = '+helper.dateToEpoch(photoDate)+', \
        updatedDate = '+helper.dateToEpoch(new Date())+' \
        WHERE id = '+id+';',
        function(err) {
            console.log('updatePhoto UPDATE result: '+err);
            db.get('SELECT * FROM photos WHERE id = '+id+';', function(err, row) {
                console.log('updatePhoto SELECT result: ' + err);
                cb(row);
            });
        });
}