from __future__ import annotations

import re
import sys
from pathlib import Path

if sys.version_info >= (3, 11):
    import tomllib
else:
    import tomli as tomllib

from depaudit.parsers import Parser, ParsedManifest


class PythonParser(Parser):
    language = "python"

    def can_parse(self, file_path: Path) -> bool:
        return file_path.name in (
            "requirements.txt",
            "requirements-dev.txt",
            "requirements.txt",
            "setup.py",
            "setup.cfg",
            "pyproject.toml",
            "Pipfile",
            "Pipfile.lock",
        )

    def parse(self, file_path: Path) -> ParsedManifest:
        manifest = ParsedManifest(
            language=self.language,
            file_path=file_path,
        )

        if file_path.name == "pyproject.toml":
            self._parse_pyproject_toml(file_path, manifest)
        elif file_path.name == "requirements.txt":
            self._parse_requirements_txt(file_path, manifest)
        elif file_path.name == "setup.py":
            self._parse_setup_py(file_path, manifest)
        elif file_path.name == "setup.cfg":
            self._parse_setup_cfg(file_path, manifest)
        elif file_path.name == "Pipfile":
            self._parse_pipfile(file_path, manifest)
        elif file_path.name == "Pipfile.lock":
            self._parse_pipfile_lock(file_path, manifest)

        return manifest

    def _parse_pyproject_toml(self, file_path: Path, manifest: ParsedManifest) -> None:
        with open(file_path, "rb") as f:
            data = tomllib.load(f)

        project = data.get("project", {})
        manifest.project_name = project.get("name")
        manifest.project_version = project.get("version")

        dependencies = project.get("dependencies", [])
        for dep in dependencies:
            name, version = self._parse_requirement_string(dep)
            if name:
                manifest.dependencies.append(
                    self._create_dependency(file_path, name, version)
                )

        optional_dependencies = project.get("optional-dependencies", {})
        for group, deps in optional_dependencies.items():
            for dep in deps:
                name, version = self._parse_requirement_string(dep)
                if name:
                    manifest.dependencies.append(
                        self._create_dependency(
                            file_path, name, version, optional=(group != "dev")
                        )
                    )

        build = data.get("build-system", {})
        if "requires" in build:
            for req in build["requires"]:
                if isinstance(req, str) and not req.startswith("setuptools"):
                    name, version = self._parse_requirement_string(req)
                    if name:
                        manifest.dependencies.append(
                            self._create_dependency(file_path, name, version)
                        )

        manifest.raw_data = data

    def _parse_requirements_txt(self, file_path: Path, manifest: ParsedManifest) -> None:
        with open(file_path, "r", encoding="utf-8") as f:
            content = f.read()

        for line in content.split("\n"):
            line = line.strip()
            if not line or line.startswith("#"):
                continue

            name, version = self._parse_requirement_string(line)
            if name:
                dev = "-dev" in line or "-dev" in name.lower()
                manifest.dependencies.append(
                    self._create_dependency(file_path, name, version, dev=dev)
                )

    def _parse_setup_py(self, file_path: Path, manifest: ParsedManifest) -> None:
        content = file_path.read_text(encoding="utf-8")

        install_requires_match = re.search(
            r"install_requires\s*=\s*\[(^\]]*)\]", content, re.DOTALL
        )
        if install_requires_match:
            deps_str = install_requires_match.group(1)
            for dep in re.findall(r'"([^"]+)"', deps_str):
                name, version = self._parse_requirement_string(dep)
                if name:
                    manifest.dependencies.append(
                        self._create_dependency(file_path, name, version)
                    )

        name_match = re.search(r'name\s*=\s*["']([^"']+)["']', content)
        if name_match:
            manifest.project_name = name_match.group(1)

        version_match = re.search(r'version\s*=\s*["']([^"']+)["']', content)
        if version_match:
            manifest.project_version = version_match.group(1)

    def _parse_setup_cfg(self, file_path: Path, manifest: ParsedManifest) -> None:
        content = file_path.read_text(encoding="utf-8")

        install_requires_match = re.search(
            r"install_requires\s*=\s*([^\n]+)", content
        )
        if install_requires_match:
            deps = install_requires_match.group(1).split()
            for dep in deps:
                if dep.startswith("-e"):
                    continue
                name, version = self._parse_requirement_string(dep)
                if name:
                    manifest.dependencies.append(
                        self._create_dependency(file_path, name, version)
                    )

    def _parse_pipfile(self, file_path: Path, manifest: ParsedManifest) -> None:
        content = file_path.read_text(encoding="utf-8")

        name_match = re.search(r'name\s*=\s*["']([^"']+)["']', content)
        if name_match:
            manifest.project_name = name_match.group(1)

        for section in ["packages", "dev-packages"]:
            section_match = re.search(
                rf'{section}\s*=\s*\{{([^}}]+)\}}', content, re.DOTALL
            )
            if section_match:
                deps_block = section_match.group(1)
                for match in re.finditer(r'"([^"]+)"', deps_block):
                    dep_str = match.group(1)
                    name, version = self._parse_requirement_string(dep_str)
                    if name:
                        manifest.dependencies.append(
                            self._create_dependency(
                                file_path, name, version, dev=(section == "dev-packages")
                            )
                        )

    def _parse_pipfile_lock(self, file_path: Path, manifest: ParsedManifest) -> None:
        import json

        data = json.loads(file_path.read_text(encoding="utf-8"))

        manifest.project_name = data.get("name")
        manifest.project_version = data.get("version")

        for name, info in data.get("default", {}).items():
            version = info.get("version", "").replace("==", "")
            manifest.dependencies.append(
                self._create_dependency(file_path, name, version)
            )

        for name, info in data.get("develop", {}).items():
            version = info.get("version", "").replace("==", "")
            manifest.dependencies.append(
                self._create_dependency(file_path, name, version, dev=True)
            )

    def _parse_requirement_string(self, req: str) -> tuple[str, str]:
        req = req.strip()
        if not req:
            return "", ""

        extras_match = re.match(r"([^\[]+)(?:\[([^\]]+)\])?", req)
        if extras_match:
            name = extras_match.group(1)
        else:
            name = req

        for op in ["==", ">=", "<=", "~=", "!=", ">", "<", "==="]:
            if op in name:
                parts = name.split(op)
                name = parts[0].strip()
                version = parts[1].strip() if len(parts) > 1 else ""
                break
        else:
            version = ""

        name = name.lower().replace("_", "-")

        return name, version