import re
from collections import Counter
from typing import Optional

from loglens.analyzers.patterns import PatternLibrary
from loglens.analyzers.severity import SeverityClassifier
from loglens.parsers.base import LogFormat, ParsedEntry


class AnalysisResult:
    """Result of log analysis."""

    def __init__(
        self,
        total_lines: int,
        entries: list[ParsedEntry],
        format_detected: LogFormat,
        error_count: int = 0,
        warning_count: int = 0,
        critical_count: int = 0,
        debug_count: int = 0,
        suggestions: Optional[list[str]] = None,
    ):
        self.total_lines = total_lines
        self.entries = entries
        self.format_detected = format_detected
        self.error_count = error_count
        self.warning_count = warning_count
        self.critical_count = critical_count
        self.debug_count = debug_count
        self.suggestions = suggestions or []

    def to_dict(self) -> dict:
        """Convert to dictionary."""
        return {
            "total_lines": self.total_lines,
            "entries": [e.to_dict() for e in self.entries],
            "format_detected": self.format_detected.value,
            "error_count": self.error_count,
            "warning_count": self.warning_count,
            "critical_count": self.critical_count,
            "debug_count": self.debug_count,
            "suggestions": self.suggestions,
        }


class LogAnalyzer:
    """Main analyzer for log files."""

    def __init__(self):
        self.patterns = PatternLibrary()
        self.severity_classifier = SeverityClassifier()

    def analyze(
        self, lines: list[str], format_enum: Optional[LogFormat] = None
    ) -> AnalysisResult:
        """Analyze a list of log lines."""
        entries = []
        error_count = 0
        warning_count = 0
        critical_count = 0
        debug_count = 0

        detected_format = format_enum

        for line in lines:
            if not line.strip():
                continue

            entry = self._parse_line(line, format_enum)
            if entry:
                entries.append(entry)
                severity = self._classify_entry(entry)
                entry.severity = severity

                if severity == "critical":
                    critical_count += 1
                elif severity == "error":
                    error_count += 1
                elif severity == "warning":
                    warning_count += 1
                elif severity == "debug":
                    debug_count += 1

                if detected_format is None:
                    detected_format = entry.format

        suggestions = self._generate_suggestions(entries)

        return AnalysisResult(
            total_lines=len(lines),
            entries=entries,
            format_detected=detected_format or LogFormat.RAW,
            error_count=error_count,
            warning_count=warning_count,
            critical_count=critical_count,
            debug_count=debug_count,
            suggestions=suggestions,
        )

    def analyze_file(
        self, file_path: str, format_enum: Optional[LogFormat] = None
    ) -> AnalysisResult:
        """Analyze a log file."""
        with open(file_path, "r") as f:
            lines = f.readlines()
        return self.analyze(lines, format_enum)

    def _parse_line(
        self, line: str, format_enum: Optional[LogFormat] = None
    ) -> Optional[ParsedEntry]:
        """Parse a single log line."""
        from loglens.parsers.factory import ParserFactory

        if format_enum:
            parser = ParserFactory.get_parser(format_enum)
            entry = parser.parse(line)
            if entry:
                return entry

        for fmt in LogFormat:
            if fmt == LogFormat.RAW:
                continue
            parser = ParserFactory.get_parser(fmt)
            entry = parser.parse(line)
            if entry:
                return entry

        return ParsedEntry(
            raw_line=line.strip(),
            format=LogFormat.RAW,
            timestamp=None,
            level=None,
            message=line.strip(),
            metadata={},
        )

    def _classify_entry(self, entry: ParsedEntry) -> str:
        """Classify severity of an entry."""
        content = entry.message

        patterns_by_severity = self.patterns.get_patterns_for_content(content)

        if patterns_by_severity:
            severities = [p.severity for p in patterns_by_severity]
            if "critical" in severities:
                return "critical"
            elif "error" in severities:
                return "error"
            elif "warning" in severities:
                return "warning"
            elif "debug" in severities:
                return "debug"

        return self.severity_classifier.classify(content, entry.level)

    def _generate_suggestions(self, entries: list[ParsedEntry]) -> list[str]:
        """Generate suggestions based on analysis."""
        suggestions = []

        error_entries = [e for e in entries if e.severity in ("error", "critical")]

        if not error_entries:
            return ["No errors detected. Keep up the good work!"]

        error_messages = [e.message for e in error_entries]
        error_counter = Counter(error_messages)

        common_errors = error_counter.most_common(5)

        if len(common_errors) > 3:
            suggestions.append(
                f"Found {len(error_entries)} errors across {len(common_errors)} unique error messages."
            )

        for error_msg, count in common_errors[:3]:
            if count > 1:
                suggestions.append(f"'{error_msg[:50]}...' occurred {count} times")

        stack_trace_entries = [
            e for e in error_entries if "Traceback" in e.message or "stack" in e.message.lower()
        ]
        if stack_trace_entries:
            suggestions.append(
                "Multiple stack traces detected. Consider checking the exception types and their root causes."
            )

        connection_errors = [
            e for e in error_entries if "connection" in e.message.lower() or "timeout" in e.message.lower()
        ]
        if len(connection_errors) > len(error_entries) * 0.3:
            suggestions.append(
                "High proportion of connection/timeout errors. Check network connectivity and service availability."
            )

        return suggestions

    def list_patterns_by_group(self) -> dict[str, list[dict]]:
        """List all patterns grouped by category."""
        return self.patterns.get_all_patterns()