import sys
import sqlite3
import numpy as np


IS_PYTHON3 = sys.version_info[0] >= 3

MAX_IMAGE_ID = 2**31 - 1
CREATE_CAMERAS_TABLE = """CREATE TABLE IF NOT EXISTS cameras (
    camera_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
    model INTEGER NOT NULL,
    width INTEGER NOT NULL,
    height INTEGER NOT NULL,
    params BLOB,
    prior_focal_length INTEGER NOT NULL)"""

CREATE_DESCRIPTORS_TABLE = """CREATE TABLE IF NOT EXISTS descriptors (
    image_id INTEGER PRIMARY KEY NOT NULL,
    rows INTEGER NOT NULL,
    cols INTEGER NOT NULL,
    data BLOB,
    FOREIGN KEY(image_id) REFERENCES images(image_id) ON DELETE CASCADE)"""

CREATE_IMAGES_TABLE = """CREATE TABLE IF NOT EXISTS images (
    image_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
    name TEXT NOT NULL UNIQUE,
    camera_id INTEGER NOT NULL,
    prior_qw REAL,
    prior_qx REAL,
    prior_qy REAL,
    prior_qz REAL,
    prior_tx REAL,
    prior_ty REAL,
    prior_tz REAL,
    CONSTRAINT image_id_check CHECK(image_id >= 0 and image_id < {}),
    FOREIGN KEY(camera_id) REFERENCES cameras(camera_id))
""".format(MAX_IMAGE_ID)
CREATE_TWO_VIEW_GEOMETRIES_TABLE = """
CREATE TABLE IF NOT EXISTS two_view_geometries (
    pair_id INTEGER PRIMARY KEY NOT NULL,
    rows INTEGER NOT NULL,
    cols INTEGER NOT NULL,
    data BLOB,
    config INTEGER NOT NULL,
    F BLOB,
    E BLOB,
    H BLOB)
"""

CREATE_KEYPOINTS_TABLE = """CREATE TABLE IF NOT EXISTS keypoints (
    image_id INTEGER PRIMARY KEY NOT NULL,
    rows INTEGER NOT NULL,
    cols INTEGER NOT NULL,
    data BLOB,
    FOREIGN KEY(image_id) REFERENCES images(image_id) ON DELETE CASCADE)
"""

CREATE_MATCHES_TABLE = """CREATE TABLE IF NOT EXISTS matches (
    pair_id INTEGER PRIMARY KEY NOT NULL,
    rows INTEGER NOT NULL,
    cols INTEGER NOT NULL,
    data BLOB)"""
CREATE_NAME_INDEX = \
    "CREATE UNIQUE INDEX IF NOT EXISTS index_name ON images(name)"

CREATE_ALL = "; ".join([
    CREATE_CAMERAS_TABLE,
    CREATE_IMAGES_TABLE,
    CREATE_KEYPOINTS_TABLE,
    CREATE_DESCRIPTORS_TABLE,
    CREATE_MATCHES_TABLE,
    CREATE_TWO_VIEW_GEOMETRIES_TABLE,
    CREATE_NAME_INDEX
])
def image_ids_to_pair_id(image_id1, image_id2):
    if image_id1 > image_id2:
        image_id1, image_id2 = image_id2, image_id1
    return image_id1 * MAX_IMAGE_ID + image_id2


def pair_id_to_image_ids(pair_id):
    image_id2 = pair_id % MAX_IMAGE_ID
    image_id1 = (pair_id - image_id2) / MAX_IMAGE_ID
    return image_id1, image_id2


def array_to_blob(array):
    if IS_PYTHON3:
        return array.tostring()
    else:
        return np.getbuffer(array)


def blob_to_array(blob, dtype, shape=(-1,)):
    if IS_PYTHON3:
        return np.fromstring(blob, dtype=dtype).reshape(*shape)
    else:
        return np.frombuffer(blob, dtype=dtype).reshape(*shape)
    
class COLMAPDatabase(sqlite3.Connection):

    @staticmethod
    def connect(database_path):
        return sqlite3.connect(database_path, factory=COLMAPDatabase)


    def __init__(self, *args, **kwargs):
        super(COLMAPDatabase, self).__init__(*args, **kwargs)

        self.create_tables = lambda: self.executescript(CREATE_ALL)
        self.create_cameras_table = \
            lambda: self.executescript(CREATE_CAMERAS_TABLE)
        self.create_descriptors_table = \
            lambda: self.executescript(CREATE_DESCRIPTORS_TABLE)
        self.create_images_table = \
            lambda: self.executescript(CREATE_IMAGES_TABLE)
        self.create_two_view_geometries_table = \
            lambda: self.executescript(CREATE_TWO_VIEW_GEOMETRIES_TABLE)
        self.create_keypoints_table = \
            lambda: self.executescript(CREATE_KEYPOINTS_TABLE)
        self.create_matches_table = \
            lambda: self.executescript(CREATE_MATCHES_TABLE)
        self.create_name_index = lambda: self.executescript(CREATE_NAME_INDEX)

    def add_camera(self, model, width, height, params,#params
                   prior_focal_length=False, camera_id=None):
        params = np.asarray(params, np.float64)
        cursor = self.execute(
            "INSERT INTO cameras VALUES (?, ?, ?, ?, ?, ?)",
            (camera_id, model, width, height, array_to_blob(params),
             prior_focal_length))
        return cursor.lastrowid
    def add_image(self, name, camera_id,
                  prior_q=np.zeros(4), prior_t=np.zeros(3), image_id=None):
        cursor = self.execute(
            "INSERT INTO images VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
            (image_id, name, camera_id, prior_q[0], prior_q[1], prior_q[2],
             prior_q[3], prior_t[0], prior_t[1], prior_t[2]))
        return cursor.lastrowid # the last id

    def add_keypoints(self, image_id, keypoints):
        assert(len(keypoints.shape) == 2)
        assert(keypoints.shape[1] in [2, 4, 6])

        keypoints = np.asarray(keypoints, np.float32)
        self.execute(
            "INSERT INTO keypoints VALUES (?, ?, ?, ?)",
            (image_id,) + keypoints.shape + (array_to_blob(keypoints),))

    def add_descriptors(self, image_id, descriptors):
        descriptors = np.ascontiguousarray(descriptors, np.uint8) 
        self.execute(# arrary 
            "INSERT INTO descriptors VALUES (?, ?, ?, ?)",
            (image_id,) + descriptors.shape + (array_to_blob(descriptors),))

    def add_matches(self, image_id1, image_id2, matches):
        assert(len(matches.shape) == 2)
        assert(matches.shape[1] == 2)

        if image_id1 > image_id2:
            matches = matches[:,::-1]

        pair_id = image_ids_to_pair_id(image_id1, image_id2)
        matches = np.asarray(matches, np.uint32)
        self.execute(
            "INSERT INTO matches VALUES (?, ?, ?, ?)",
            (pair_id,) + matches.shape + (array_to_blob(matches),))
    def add_two_view_geometry(self, image_id1, image_id2, matches,
                              F=np.eye(3), E=np.eye(3), H=np.eye(3), config=2):
        assert(len(matches.shape) == 2)
        assert(matches.shape[1] == 2)

        if image_id1 > image_id2:
            matches = matches[:,::-1]

        pair_id = image_ids_to_pair_id(image_id1, image_id2)
        matches = np.asarray(matches, np.uint32)
        F = np.asarray(F, dtype=np.float64)
        E = np.asarray(E, dtype=np.float64)
        H = np.asarray(H, dtype=np.float64)
        self.execute(
            "INSERT INTO two_view_geometries VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
            (pair_id,) + matches.shape + (array_to_blob(matches), config,
             array_to_blob(F), array_to_blob(E), array_to_blob(H)))