# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.

import io
import os
import re

from .ini import combine_fields

__all__ = ["read_toml", "alphabetize_toml_str", "add_skip_if", "sort_paths"]

FILENAME_REGEX = r"^([A-Za-z0-9_./-]*)([Bb][Uu][Gg])([-_]*)([0-9]+)([A-Za-z0-9_./-]*)$"
DEFAULT_SECTION = "DEFAULT"


def sort_paths_keyfn(k):
    sort_paths_keyfn.rx = getattr(sort_paths_keyfn, "rx", None)  # static
    if sort_paths_keyfn.rx is None:
        sort_paths_keyfn.rx = re.compile(FILENAME_REGEX)
    name = str(k)
    if name == DEFAULT_SECTION:
        return ""
    m = sort_paths_keyfn.rx.findall(name)
    if len(m) == 1 and len(m[0]) == 5:
        prefix = m[0][0]  # text before "Bug"
        bug = m[0][1]  # the word "Bug"
        underbar = m[0][2]  # underbar or dash (optional)
        num = m[0][3]  # the bug id
        suffix = m[0][4]  # text after the bug id
        name = f"{prefix}{bug.lower()}{underbar}{int(num):09d}{suffix}"
        return name
    return name


def sort_paths(paths):
    """
    Returns a list of paths (tests) in a manifest in alphabetical order.
    Ensures DEFAULT is first and filenames with a bug number are
    in the proper order.
    """
    return sorted(paths, key=sort_paths_keyfn)


def parse_toml_str(contents):
    """
    Parse TOML contents using toml
    """
    import toml

    error = None
    manifest = None
    try:
        manifest = toml.loads(contents)
    except toml.TomlDecodeError as pe:
        error = str(pe)
    return error, manifest


def parse_tomlkit_str(contents):
    """
    Parse TOML contents using tomlkit
    """
    import tomlkit
    from tomlkit.exceptions import TOMLKitError

    error = None
    manifest = None
    try:
        manifest = tomlkit.parse(contents)
    except TOMLKitError as pe:
        error = str(pe)
    return error, manifest


def read_toml(
    fp,
    defaults=None,
    default=DEFAULT_SECTION,
    _comments=None,
    _separators=None,
    strict=True,
    handle_defaults=True,
    document=False,
    add_line_no=False,
):
    """
    read a .toml file and return a list of [(section, values)]
    - fp : file pointer or path to read
    - defaults : default set of variables
    - default : name of the section for the default section
    - comments : characters that if they start a line denote a comment
    - separators : strings that denote key, value separation in order
    - strict : whether to be strict about parsing
    - handle_defaults : whether to incorporate defaults into each section
    - document: read TOML with tomlkit and return source in test["document"]
    - add_line_no: add the line number where the test name appears in the file to the source. Also, the document variable must be set to True for this flag to work. (This is used only to generate the documentation)
    """

    # variables
    defaults = defaults or {}
    default_section = {}
    sections = []
    if isinstance(fp, str):
        filename = fp
        fp = io.open(fp, encoding="utf-8")
    elif hasattr(fp, "name"):
        filename = fp.name
    else:
        filename = "unknown"
    contents = fp.read()
    inline_comment_rx = re.compile(r"\s#.*$")

    if document:  # Use tomlkit to parse the file contents
        error, manifest = parse_tomlkit_str(contents)
    else:
        error, manifest = parse_toml_str(contents)
    if error:
        raise IOError(f"Error parsing TOML manifest file {filename}: {error}")

    # handle each section of the manifest
    for section in manifest.keys():
        current_section = {}
        for key in manifest[section].keys():
            val = manifest[section][key]
            if isinstance(val, bool):  # must coerce to lowercase string
                if val:
                    val = "true"
                else:
                    val = "false"
            elif isinstance(val, list):
                new_vals = ""
                for v in val:
                    if len(new_vals) > 0:
                        new_vals += os.linesep
                    new_val = str(v).strip()  # coerce to str
                    comment_found = inline_comment_rx.search(new_val)
                    if comment_found:
                        new_val = new_val[0 : comment_found.span()[0]]
                    if " = " in new_val:
                        raise Exception(
                            f"Should not assign in {key} condition for {section}"
                        )
                    new_vals += new_val
                val = new_vals
            else:
                val = str(val).strip()  # coerce to str
                comment_found = inline_comment_rx.search(val)
                if comment_found:
                    val = val[0 : comment_found.span()[0]]
                if " = " in val:
                    raise Exception(
                        f"Should not assign in {key} condition for {section}"
                    )
            current_section[key] = val
        if section.lower() == default.lower():
            default_section = current_section
            # DEFAULT does NOT appear in the output
        else:
            sections.append((section, current_section))

    # merge global defaults with the DEFAULT section
    defaults = combine_fields(defaults, default_section)
    if handle_defaults:
        # merge combined defaults into each section
        sections = [(i, combine_fields(defaults, j)) for i, j in sections]

    if document and add_line_no:
        # Take the line where the test name appears in the file.
        for i, _ in enumerate(sections):
            line = contents.split(sections[i][0])[0].count(os.linesep) + 1
            manifest.setdefault(sections[i][0], {})["lineno"] = str(line)
    elif not document:
        manifest = None

    return sections, defaults, manifest


def alphabetize_toml_str(manifest):
    """
    Will take a TOMLkit manifest document (i.e. from a previous invocation
    of read_toml(..., document=True) and accessing the document
    from mp.source_documents[filename]) and return it as a string
    in sorted order by section (i.e. test file name, taking bug ids into consideration).
    """

    from tomlkit import document, dumps, table
    from tomlkit.items import Table

    preamble = ""
    new_manifest = document()
    first_section = False
    sections = {}

    for k, v in manifest.body:
        if k is None:
            preamble += v.as_string()
            continue
        if not isinstance(v, Table):
            raise Exception(f"MP TOML illegal keyval in preamble: {k} = {v}")
        section = None
        if not first_section:
            if k == DEFAULT_SECTION:
                new_manifest.add(k, v)
            else:
                new_manifest.add(DEFAULT_SECTION, table())
            first_section = True
        else:
            values = v.items()
            if len(values) == 1:
                for kk, vv in values:
                    if isinstance(vv, Table):  # unquoted, dotted key
                        section = f"{k}.{kk}"
                        sections[section] = vv
        if section is None:
            section = str(k).strip("'\"")
            sections[section] = v

    if not first_section:
        new_manifest.add(DEFAULT_SECTION, table())

    for section in sort_paths([k for k in sections.keys() if k != DEFAULT_SECTION]):
        new_manifest.add(section, sections[section])

    manifest_str = dumps(new_manifest)
    # tomlkit fixups
    manifest_str = preamble + manifest_str.replace('"",]', "]")
    while manifest_str.endswith("\n\n"):
        manifest_str = manifest_str[:-1]
    return manifest_str


def _simplify_comment(comment):
    """Remove any leading #, but preserve leading whitespace in comment"""
    if comment is None:
        return None

    length = len(comment)
    i = 0
    j = -1  # remove exactly one space
    while i < length and comment[i] in " #":
        i += 1
        if comment[i] == " ":
            j += 1
    comment = comment[i:]
    if j > 0:
        comment = " " * j + comment
    return comment.rstrip()


def _should_keep_condition(existing_condition: str, new_condition: str):
    """
    Checks if there is any overlap between the existing condition and the new one.
    Existing conditions too simple or too complex should be replaced by the new one.
    If both are equal, then we keep the existing to prevent changing the order of conditions
    """
    return existing_condition == new_condition or not (
        existing_condition in new_condition or new_condition in existing_condition
    )


def add_skip_if(manifest, filename, condition, bug=None):
    """
    Will take a TOMLkit manifest document (i.e. from a previous invocation
    of read_toml(..., document=True) and accessing the document
    from mp.source_documents[filename]) and return it as a string
    in sorted order by section (i.e. test file name, taking bug ids into consideration).
    """
    from tomlkit import array
    from tomlkit.items import Comment, String, Whitespace

    if filename not in manifest:
        raise Exception(f"TOML manifest does not contain section: {filename}")
    keyvals = manifest[filename]
    first = None
    first_comment = ""
    skip_if = None
    existing = False  # this condition is already present
    if "skip-if" in keyvals:
        skip_if = keyvals["skip-if"]
        if len(skip_if) == 1:
            for e in skip_if._iter_items():
                if not first:
                    if not isinstance(e, Whitespace):
                        first = e.as_string().strip('"')
                else:
                    c = e.as_string()
                    if c != ",":
                        first_comment += c
            if skip_if.trivia is not None:
                first_comment += skip_if.trivia.comment
    mp_array = array()
    if skip_if is None:  # add the first one line entry to the table
        mp_array.add_line(condition, indent="", add_comma=False, newline=False)
        if bug is not None:
            mp_array.comment(bug)
        skip_if = {"skip-if": mp_array}
        keyvals.update(skip_if)
    else:
        # We store the conditions in a regular python array so we can sort them before
        # dumping them in the TOML
        conditions_array = []
        if first is not None:
            if first == condition:
                existing = True
            if first_comment is not None and _should_keep_condition(first, condition):
                conditions_array.append([first, _simplify_comment(first_comment)])
        if len(skip_if) > 1:
            e_condition = None
            e_comment = None
            for e in skip_if._iter_items():
                if isinstance(e, String):
                    if e_condition is not None:
                        if _should_keep_condition(e_condition, condition):
                            conditions_array.append([e_condition, e_comment])
                        e_comment = None
                        e_condition = None
                    if len(e) > 0:
                        e_condition = e.as_string().strip('"')
                        if e_condition == condition:
                            existing = True
                elif isinstance(e, Comment):
                    e_comment = _simplify_comment(e.as_string())
            if e_condition is not None and _should_keep_condition(
                e_condition, condition
            ):
                conditions_array.append([e_condition, e_comment])
        if not existing:
            conditions_array.append([condition, bug])
        conditions_array.sort()
        for c in conditions_array:
            mp_array.add_line(c[0], indent="  ", comment=c[1])
        mp_array.add_line("", indent="")  # fixed in write_toml_str
        skip_if = {"skip-if": mp_array}
        del keyvals["skip-if"]
        keyvals.update(skip_if)
