#!/usr/bin/python3
# TODO: get rid of the -n option; multiple files are prefixed by 'filename:', single files aren't

VERSION = "0.3"

import os, sys, argparse, xattr, json, sqlite3

answer_json = []
verbose = 0
db = None
xattr_comment = "user.xdg.comment"
xattr_author    = "user.xdg.comment.author"
xattr_date      = "user.xdg.comment.date"

#======= debugging/verbose ===========
def print_d(*a):
    if verbose > 1:
        print('>>',*a)
def print_v(*a):
    if verbose:
        print('>',*a)

#============= the functions that are called from the main.loop ===============

def file_copy(f,target,target_is_dir,force):
    print_d(f"call file_copy with args={target},{target_is_dir} and {force}")
    dest = target if not target_is_dir else target+'/'+os.path.basename(f)
    if os.path.exists(dest) and not force:
        go = input("The copy target <<" + dest + ">> exists. Overwrite? (y or n) ")
        if go != 'y' and go != 'Y':
            return
    print_d(f"copy from {f} to {dest}")

def file_zap(f,all_flag):
    print_d(f"zapping the comment history of {f}")
    if all_flag:
        print_d("zapping the entire database")

def file_modify_comment(f, create, append, erase):
    print_d(f"modify the comment on file {f} with extra={(create,append,erase)}")
    if not os.path.exists(f):
        print(f"the target file does not exist; please check the spelling of the file: {f}")
        # sys.exit() here?

def file_display(f, listall, history, json, minimal):
    print_d(f"list file details {f}")
    x_comment = None
    try:
        x_comment = xattr.getxattr(f,xattr_comment).decode()
        x_author    = xattr.getxattr(f,xattr_author).decode()
        x_date      = xattr.getxattr(f,xattr_date).decode()
    except:
        pass
    full_f = os.path.realpath(f)

    d_comment = getDbComment(full_f)
    if d_comment:
        d_comment, d_author, d_date = d_comment
    print_d(f"for file {f}, database comment is <{d_comment}>, xattr comment is <{x_comment}>")

    if os.path.isdir(f):
        f = f+'/'
    if x_comment or listall:
        if x_comment and (d_comment != x_comment):
            x_comment += '*'
        if not json:
            if minimal:
                print(f"{x_comment}")
            else:
                print(f"{f}: {x_comment}")
        else:
            if verbose:
                answer_json.append( {"file":f,"comment":x_comment,"author":x_author,"date":x_date } )
            else:
                answer_json.append( {"file":f,"comment":x_comment} )

def getDbComment(full_filename):
    global db
    print_d(f"db access for {full_filename}")
    c = db.cursor()
    c.execute("select comment,author,comment_date from dirnotes where name=? and comment<>'' order by comment_date desc",(full_filename,))
    a = c.fetchone()
    if a:
        return a[0:3]

def openDb():
    global db
    dbName = "~/.dirnotes.db"
    dbName = os.path.expanduser(dbName)
    db = sqlite3.connect(dbName)
    try:
        c = db.cursor()
        c.execute("select * from dirnotes")
    except sqlite3.OperationalError:
        c.execute("create table dirnotes (name TEXT, date DATETIME, size INTEGER, comment TEXT, comment_date DATETIME, author TEXT)")
    return db 

def main(args):
    parser = argparse.ArgumentParser(description="Display or add comments to files",
        epilog="Some options conflict. Use only one of: -l -c -a -H -e -z -Z and one of -d -x")
    parser.add_argument('-V',"--version", action="version",     version=f"dncli ver:{VERSION}")
    parser.add_argument('-v',"--verbose", action='count',           help="verbose, almost debugging; do not use in scripts",default=0)
    parser.add_argument('-j',"--json",      action="store_true",help="output in JSON format")
    pars_m = parser.add_mutually_exclusive_group()
    pars_m.add_argument('-l',"--listall", action="store_true",help="list all files, including those without comments")
    parser.add_argument('-d',"--db",            action="store_true",help="list comments from database")
    parser.add_argument('-x',"--xattr",     action="store_true",help="list comments from xattr")
    parser.add_argument('-n',"--minimal", action="store_true",help="output only comments; useful in scripting")
    parser.add_argument('-H',"--history", action="store_true",help="output the history of comments for a file")
    pars_m.add_argument('-c',"--create",    metavar="comment",  help="add a comment to a file")
    pars_m.add_argument('-a',"--append",    metavar="comment",  help="append to a comment on a file, separator=';'")
    pars_m.add_argument('-C',"--copy",      action="store_true",help="copy a file with its comments")
    parser.add_argument('-y',"--cp_force",action="store_true",help="copy over existing files")
    pars_m.add_argument('-e',"--erase",     action="store_true",help="erase the comment on a file")
    pars_m.add_argument('-z',"--zap",           action="store_true",help="clear the comment history on a file")
    pars_m.add_argument('-Z',"--zapall",     action="store_true",help="clear the comment history in the entire database")
    parser.add_argument('file_list',nargs='*',help="file(s); list commands may omit this")
    args = parser.parse_args()

    # default is to display all files that have comments

    # major modes are: display (<none> -l -H), add-comment (-a -c -e), clear-history(-z -Z), copy (-C)
    # determine the major mode, then apply an appropriate function over the file_list
    
    args.display = not (args.create or args.append or args.copy or args.erase or args.zap or args.zapall)
    if args.cp_force and not args.copy:
        print("the -y/--cp_force options can only be used with the -C/--copy command")
        sys.exit(3)     
    if args.json and not args.display:
        print("the -j/--json option can only be used with the display modes")
        sys.exit(4)
    if args.minimal and not args.display:
        print("the -n/--minimal option only applies to the display modes")
        sys.exit(5)
    if args.history and not args.display:
        print("the -H/--history option only applies to the display modes")
        sys.exit(5)
    if args.xattr and (args.zap or args.zapall):
        print("the -x/--xattr option doesn't apply to the -z/--zap and -Z/--zapall commands")
        sys.exit(7)

    global verbose
    verbose = args.verbose
    
    #====== 1) build the file list =============

    files = args.file_list
    # for the list commands, auto-fill the file list with the current directory
    if not files and args.display:
        files = os.listdir(".")
        files.sort()
    # other command require explicity file lists, but 'dncli -c "new comment" *' will work
    if not files:
        print("please specify a file or files to use")
        sys.exit(10)
    print_d("got the files:", files)

    #======= 2) build the function
    if args.create or args.append or args.erase:
        print_d(f"create/append/erase: {args.create} . {args.append} . {args.erase}")
        func = file_modify_comment
        loop_args = (args.create, args.append, args.erase)
    elif args.zap or args.zapall:
        print_d(f"got a zap command {args.zap} . {args.zapall}")
        func = file_zap
        loop_args = (args.zapall,)
        if args.zapall:
            files = (1,)
    elif args.copy:
        print_d(f"got a copy command to {args.copy}")
        # the last item on the file list is the target
        n_files = len(files)
        if n_files < 2:
            print_d(f"the copy command requires at least two arguments, the last one is the destination")
            sys.exit(1)
        target = files[-1]
        target_is_directory = os.path.isdir(target)
        files = files[:-1]
        print_d(f"copy from {files} to {target}")
        if n_files > 2 and not target_is_directory:
            print_d(f"multiple copy files must go to a target directory")
            sys.exit(3)
        func = file_copy
        loop_args = (target, target_is_directory, args.cp_force)
    else:
        assert(args.display)
        print_v(f"list files using {'database' if args.db else 'xattr'} priority")
        print_d(f"display command with option: {args.listall} and {args.history} and {args.json} and {args.minimal}")
        loop_args = (args.listall, args.history, args.json, args.minimal)
        func = file_display

    #====== 3) loop on the list, execute the function =============
    global db
    db = openDb()

    for f in files:
        func(f,*loop_args)

    if answer_json:
        print(json.dumps(answer_json))

if __name__ == "__main__":
    main(sys.argv)