#!/usr/bin/env python3
"""
Module Dependency Graph Generator

Analyzes the codebase and outputs a dependency graph showing how modules
depend on each other. Useful for understanding module coupling and
identifying architectural issues.

Usage:
    python scripts/module_dependency_graph.py [--format FORMAT] [--output FILE]

Options:
    --format FORMAT   Output format: text (default), dot, json, mermaid
    --output FILE     Output file (default: stdout)
    --show-details    Show file-level dependencies
"""

import argparse
import json
import re
import sys
from collections import defaultdict
from dataclasses import dataclass, field
from pathlib import Path


@dataclass
class ModuleDependency:
    """Represents a dependency from one module to another."""
    source_module: str
    target_module: str
    source_files: list[str] = field(default_factory=list)
    import_count: int = 0


@dataclass
class ModuleInfo:
    """Information about a module."""
    name: str
    is_core: bool
    dependencies: list[str] = field(default_factory=list)
    dependents: list[str] = field(default_factory=list)
    file_count: int = 0


class ModuleDependencyAnalyzer:
    """Analyzes module dependencies in the codebase."""

    # Core modules (always enabled)
    CORE_MODULES = {
        "contracts",
        "core",
        "tenancy",
        "cms",
        "customers",
        "billing",
        "payments",
        "messaging",
    }

    # Optional modules (can be enabled/disabled per platform)
    OPTIONAL_MODULES = {
        "analytics",
        "cart",
        "catalog",
        "checkout",
        "inventory",
        "loyalty",
        "marketplace",
        "orders",
        "monitoring",
    }

    def __init__(self, project_root: Path):
        self.project_root = project_root
        self.modules_path = project_root / "app" / "modules"
        self.dependencies: dict[str, dict[str, ModuleDependency]] = defaultdict(dict)
        self.modules: dict[str, ModuleInfo] = {}

    def analyze(self) -> dict[str, ModuleInfo]:
        """Analyze all module dependencies."""
        if not self.modules_path.exists():
            print(f"Error: Modules path not found: {self.modules_path}", file=sys.stderr)
            return {}

        # First pass: discover modules
        module_dirs = [
            d for d in self.modules_path.iterdir()
            if d.is_dir() and d.name != "__pycache__" and not d.name.startswith(".")
        ]

        for module_dir in module_dirs:
            module_name = module_dir.name
            is_core = module_name in self.CORE_MODULES
            self.modules[module_name] = ModuleInfo(
                name=module_name,
                is_core=is_core,
            )

        # Second pass: analyze imports
        for module_dir in module_dirs:
            module_name = module_dir.name
            self._analyze_module(module_dir, module_name)

        # Calculate dependents
        for module_name, module_info in self.modules.items():
            for dep in self.dependencies.get(module_name, {}).values():
                module_info.dependencies.append(dep.target_module)
                if dep.target_module in self.modules:
                    self.modules[dep.target_module].dependents.append(module_name)

        return self.modules

    def _analyze_module(self, module_dir: Path, module_name: str):
        """Analyze a single module's dependencies."""
        file_count = 0
        for py_file in module_dir.rglob("*.py"):
            if "__pycache__" in str(py_file):
                continue

            file_count += 1
            try:
                content = py_file.read_text()
                self._analyze_file(py_file, content, module_name)
            except Exception as e:
                print(f"Warning: Could not analyze {py_file}: {e}", file=sys.stderr)

        if module_name in self.modules:
            self.modules[module_name].file_count = file_count

    def _analyze_file(self, file_path: Path, content: str, source_module: str):
        """Analyze imports in a single file."""
        lines = content.split("\n")
        in_docstring = False
        docstring_delimiter = None
        in_type_checking = False
        type_checking_indent = 0

        for _i, line in enumerate(lines, 1):
            stripped = line.strip()
            if stripped.startswith("#") or not stripped:
                continue

            # Track docstrings
            if '"""' in line or "'''" in line:
                for delim in ['"""', "'''"]:
                    count = line.count(delim)
                    if count == 1:
                        if not in_docstring:
                            in_docstring = True
                            docstring_delimiter = delim
                        elif docstring_delimiter == delim:
                            in_docstring = False
                            docstring_delimiter = None

            if in_docstring:
                continue

            # Track TYPE_CHECKING blocks
            current_indent = len(line) - len(line.lstrip())
            if "if TYPE_CHECKING:" in stripped or "if TYPE_CHECKING" in stripped:
                in_type_checking = True
                type_checking_indent = current_indent
                continue
            if in_type_checking and current_indent <= type_checking_indent and stripped:
                in_type_checking = False

            # Look for import statements
            import_match = re.match(
                r"^\s*(?:from\s+(app\.modules\.(\w+))|import\s+(app\.modules\.(\w+)))",
                line
            )

            if not import_match:
                continue

            target_module = import_match.group(2) or import_match.group(4)
            if not target_module or target_module == source_module:
                continue

            # Skip noqa comments
            if "noqa:" in line.lower() and "import" in line.lower():
                continue

            # Record the dependency
            if target_module not in self.dependencies[source_module]:
                self.dependencies[source_module][target_module] = ModuleDependency(
                    source_module=source_module,
                    target_module=target_module,
                )

            dep = self.dependencies[source_module][target_module]
            dep.import_count += 1
            rel_path = str(file_path.relative_to(self.project_root))
            if rel_path not in dep.source_files:
                dep.source_files.append(rel_path)

    def get_dependency_matrix(self) -> dict[str, set[str]]:
        """Return a simple dependency matrix (module -> set of dependencies)."""
        result = {}
        for module_name in self.modules:
            deps = set()
            for dep in self.dependencies.get(module_name, {}).values():
                deps.add(dep.target_module)
            result[module_name] = deps
        return result

    def find_circular_dependencies(self) -> list[tuple[str, str]]:
        """Find bidirectional dependencies (A imports B and B imports A)."""
        circular = []
        checked = set()
        for source in self.dependencies:
            for target in self.dependencies.get(source, {}):
                if (target, source) not in checked:
                    if source in self.dependencies.get(target, {}):
                        circular.append((source, target))
                    checked.add((source, target))
        return circular


def format_text(analyzer: ModuleDependencyAnalyzer, show_details: bool = False) -> str:
    """Format output as plain text."""
    lines = []
    lines.append("=" * 70)
    lines.append("MODULE DEPENDENCY GRAPH")
    lines.append("=" * 70)
    lines.append("")

    # Separate core and optional modules
    core_modules = sorted([m for m in analyzer.modules.values() if m.is_core], key=lambda x: x.name)
    optional_modules = sorted([m for m in analyzer.modules.values() if not m.is_core], key=lambda x: x.name)

    lines.append("CORE MODULES (always enabled):")
    lines.append("-" * 40)
    for module in core_modules:
        deps = analyzer.dependencies.get(module.name, {})
        deps_str = ", ".join(sorted(deps.keys())) if deps else "(none)"
        lines.append(f"  {module.name} ({module.file_count} files)")
        lines.append(f"    → depends on: {deps_str}")
        if show_details and deps:
            for dep_name, dep in sorted(deps.items()):
                lines.append(f"      - {dep_name}: {dep.import_count} imports from {len(dep.source_files)} files")
    lines.append("")

    lines.append("OPTIONAL MODULES (can be disabled):")
    lines.append("-" * 40)
    for module in optional_modules:
        deps = analyzer.dependencies.get(module.name, {})
        deps_str = ", ".join(sorted(deps.keys())) if deps else "(none)"
        lines.append(f"  {module.name} ({module.file_count} files)")
        lines.append(f"    → depends on: {deps_str}")
        if show_details and deps:
            for dep_name, dep in sorted(deps.items()):
                lines.append(f"      - {dep_name}: {dep.import_count} imports from {len(dep.source_files)} files")
    lines.append("")

    # Find circular dependencies
    circular = analyzer.find_circular_dependencies()
    if circular:
        lines.append("⚠️  BIDIRECTIONAL DEPENDENCIES (potential design issues):")
        lines.append("-" * 40)
        for a, b in circular:
            lines.append(f"  {a} ⟷ {b}")
        lines.append("")

    # Check for core→optional violations
    violations = []
    for source_module in analyzer.CORE_MODULES:
        deps = analyzer.dependencies.get(source_module, {})
        for target_module in deps:
            if target_module in analyzer.OPTIONAL_MODULES:
                violations.append((source_module, target_module, deps[target_module]))

    if violations:
        lines.append("❌ ARCHITECTURE VIOLATIONS (core → optional):")
        lines.append("-" * 40)
        for source, target, dep in violations:
            lines.append(f"  {source} → {target} ({dep.import_count} imports)")
            if show_details:
                for f in dep.source_files[:5]:
                    lines.append(f"    - {f}")
                if len(dep.source_files) > 5:
                    lines.append(f"    ... and {len(dep.source_files) - 5} more files")
        lines.append("")

    return "\n".join(lines)


def format_mermaid(analyzer: ModuleDependencyAnalyzer) -> str:
    """Format output as Mermaid diagram."""
    lines = []
    lines.append("```mermaid")
    lines.append("flowchart TD")
    lines.append('    subgraph core["Core Modules"]')
    for module in sorted(analyzer.CORE_MODULES):
        if module in analyzer.modules:
            lines.append(f"        {module}[{module}]")
    lines.append("    end")
    lines.append("")
    lines.append('    subgraph optional["Optional Modules"]')
    for module in sorted(analyzer.OPTIONAL_MODULES):
        if module in analyzer.modules:
            lines.append(f"        {module}[{module}]")
    lines.append("    end")
    lines.append("")

    # Add edges
    for source, deps in analyzer.dependencies.items():
        for target, _dep in deps.items():
            # Style violations differently
            source_is_core = source in analyzer.CORE_MODULES
            target_is_optional = target in analyzer.OPTIONAL_MODULES
            if source_is_core and target_is_optional:
                lines.append(f"    {source} -->|❌| {target}")
            else:
                lines.append(f"    {source} --> {target}")

    lines.append("```")
    return "\n".join(lines)


def format_dot(analyzer: ModuleDependencyAnalyzer) -> str:
    """Format output as GraphViz DOT."""
    lines = []
    lines.append("digraph ModuleDependencies {")
    lines.append("    rankdir=LR;")
    lines.append("    node [shape=box];")
    lines.append("")

    # Core modules cluster
    lines.append("    subgraph cluster_core {")
    lines.append('        label="Core Modules";')
    lines.append("        style=filled;")
    lines.append("        color=lightblue;")
    for module in sorted(analyzer.CORE_MODULES):
        if module in analyzer.modules:
            lines.append(f"        {module};")
    lines.append("    }")
    lines.append("")

    # Optional modules cluster
    lines.append("    subgraph cluster_optional {")
    lines.append('        label="Optional Modules";')
    lines.append("        style=filled;")
    lines.append("        color=lightyellow;")
    for module in sorted(analyzer.OPTIONAL_MODULES):
        if module in analyzer.modules:
            lines.append(f"        {module};")
    lines.append("    }")
    lines.append("")

    # Edges
    for source, deps in analyzer.dependencies.items():
        for target, _dep in deps.items():
            source_is_core = source in analyzer.CORE_MODULES
            target_is_optional = target in analyzer.OPTIONAL_MODULES
            if source_is_core and target_is_optional:
                lines.append(f'    {source} -> {target} [color=red, style=dashed, label="violation"];')
            else:
                lines.append(f"    {source} -> {target};")

    lines.append("}")
    return "\n".join(lines)


def format_json(analyzer: ModuleDependencyAnalyzer) -> str:
    """Format output as JSON."""
    data = {
        "modules": {},
        "dependencies": [],
        "circular_dependencies": [],
        "violations": [],
    }

    for name, module in analyzer.modules.items():
        data["modules"][name] = {
            "name": name,
            "is_core": module.is_core,
            "file_count": module.file_count,
            "dependencies": list(analyzer.dependencies.get(name, {}).keys()),
        }

    for source, deps in analyzer.dependencies.items():
        for target, dep in deps.items():
            data["dependencies"].append({
                "source": source,
                "target": target,
                "import_count": dep.import_count,
                "source_files": dep.source_files,
            })

    data["circular_dependencies"] = [
        {"modules": list(pair)} for pair in analyzer.find_circular_dependencies()
    ]

    for source_module in analyzer.CORE_MODULES:
        deps = analyzer.dependencies.get(source_module, {})
        for target_module in deps:
            if target_module in analyzer.OPTIONAL_MODULES:
                data["violations"].append({
                    "source": source_module,
                    "target": target_module,
                    "files": deps[target_module].source_files,
                })

    return json.dumps(data, indent=2)


def main():
    parser = argparse.ArgumentParser(
        description="Generate module dependency graph"
    )
    parser.add_argument(
        "--format",
        choices=["text", "dot", "json", "mermaid"],
        default="text",
        help="Output format (default: text)",
    )
    parser.add_argument(
        "--output",
        type=str,
        help="Output file (default: stdout)",
    )
    parser.add_argument(
        "--show-details",
        action="store_true",
        help="Show file-level dependency details",
    )
    parser.add_argument(
        "--project-root",
        type=str,
        default=".",
        help="Project root directory (default: current directory)",
    )

    args = parser.parse_args()

    project_root = Path(args.project_root).resolve()
    analyzer = ModuleDependencyAnalyzer(project_root)
    analyzer.analyze()

    # Format output
    if args.format == "text":
        output = format_text(analyzer, show_details=args.show_details)
    elif args.format == "mermaid":
        output = format_mermaid(analyzer)
    elif args.format == "dot":
        output = format_dot(analyzer)
    elif args.format == "json":
        output = format_json(analyzer)
    else:
        output = format_text(analyzer, show_details=args.show_details)

    # Write output
    if args.output:
        Path(args.output).write_text(output)
        print(f"Output written to {args.output}")
    else:
        print(output)


if __name__ == "__main__":
    main()