from __future__ import annotations

import re
from dataclasses import dataclass, field
from typing import Any

from app.services.ai_engine.base import AIQueryResult


@dataclass
class CitationPattern:
    pattern_type: str
    pattern_name: str
    frequency: float
    confidence: float
    description: str
    details: dict[str, Any] = field(default_factory=dict)


@dataclass
class PatternAnalysisReport:
    brand_id: str
    query: str
    total_results: int
    patterns: list[CitationPattern]
    content_structure_insights: dict[str, Any]
    authority_signal_insights: dict[str, Any]
    citation_format_insights: dict[str, Any]
    engine_preferences: dict[str, Any]
    recommendations: list[str] = field(default_factory=list)


_FAQ_PATTERNS = [
    re.compile(r"Q:\s*.+?\s*A:\s*", re.DOTALL | re.IGNORECASE),
    re.compile(r"问题[:：]\s*.+?\s*回答[:：]\s*", re.DOTALL),
    re.compile(r"常见问题", re.IGNORECASE),
    re.compile(r"FAQ", re.IGNORECASE),
]

_LIST_PATTERNS = [
    re.compile(r"(?:^|\n)\s*\d+\.\s+", re.MULTILINE),
    re.compile(r"(?:^|\n)\s*[-*]\s+", re.MULTILINE),
]

_TABLE_PATTERNS = [
    re.compile(r"\|.+\|.+\|", re.MULTILINE),
    re.compile(r"-{4,}\s+-{4,}", re.MULTILINE),
]

_QUOTE_PATTERNS = [
    re.compile(r"^\s*>\s+", re.MULTILINE),
    re.compile(r"[\"\u201c].+?[\"\u201d]"),
]

_DATA_CITATION_PATTERNS = [
    re.compile(r"\d+%", re.MULTILINE),
    re.compile(r"(?:study|research|survey|report|data|statistics)", re.IGNORECASE),
    re.compile(r"(?:according to|based on|shown by|indicates?|reveals?)", re.IGNORECASE),
    re.compile(r"\b(?:19|20)\d{2}\b"),
]

_EXPERT_CITATION_PATTERNS = [
    re.compile(r"(?:Dr\.|Professor|Prof\.)\s+\w+", re.IGNORECASE),
    re.compile(r"(?:expert|analyst|researcher|scientist)\s+\w+", re.IGNORECASE),
    re.compile(r"(?:from|at)\s+(?:Harvard|Stanford|MIT|Oxford|Cambridge|Yale|Princeton)", re.IGNORECASE),
]

_CERTIFICATION_PATTERNS = [
    re.compile(r"(?:ISO\s*\d+|FDA\s+approved|CE\s+certif|UL\s+listed|SOC\s*2|HIPAA|GDPR)", re.IGNORECASE),
    re.compile(r"(?:certified|certification|compliant|accredited)", re.IGNORECASE),
]

_COMPARISON_PATTERNS = [
    re.compile(r"(?:compared?\s+to|vs\.?|versus|while\s+.+\s*,\s*.+)", re.IGNORECASE),
    re.compile(r"(?:优于|相比|对比|不如|胜过)"),
]

_DIRECT_CITATION_PATTERNS = [
    re.compile(r"(?:states?|claims?|says?|mentions?|notes?|reports?|announces?)", re.IGNORECASE),
    re.compile(r"(?:according to|as stated by|as reported by)", re.IGNORECASE),
]

_CONTENT_RULES: list[tuple[str, list[re.Pattern[str]], float, str]] = [
    ("faq_format", _FAQ_PATTERNS, 0.8, "FAQ format detected in AI responses"),
    ("list_format", _LIST_PATTERNS, 0.8, "List format detected in AI responses"),
    ("table_format", _TABLE_PATTERNS, 0.8, "Table format detected in AI responses"),
    ("quote_block", _QUOTE_PATTERNS, 0.7, "Quote block detected in AI responses"),
]

_AUTHORITY_RULES: list[tuple[str, list[re.Pattern[str]], float, str, int]] = [
    ("data_citation", _DATA_CITATION_PATTERNS, 0.85, "Data citation signals detected in AI responses", 2),
    ("expert_citation", _EXPERT_CITATION_PATTERNS, 0.8, "Expert citation signals detected in AI responses", 1),
    ("certification_mark", _CERTIFICATION_PATTERNS, 0.9, "Certification marks detected in AI responses", 1),
]

_RECOMMENDATION_RULES: list[tuple[str, str, float, str]] = [
    ("content_structure", "faq_format", 0.3, "Consider adding FAQ sections to improve AI citation probability"),
    ("content_structure", "list_format", 0.3, "Use structured lists to make content more extractable by AI engines"),
    ("authority_signal", "data_citation", 0.3, "Include data citations and statistics to increase authority signals"),
    ("authority_signal", "expert_citation", 0.3, "Add expert quotes and references to strengthen E-E-A-T signals"),
    ("citation_format", "direct_citation", 0.2, "Optimize content for direct citation by AI engines"),
]


def _matches_any(text: str, patterns: list[re.Pattern[str]]) -> bool:
    return any(p.search(text) for p in patterns)


def _count_matches(text: str, patterns: list[re.Pattern[str]]) -> int:
    return sum(1 for p in patterns if p.search(text))


def _build_type_insights(
    patterns: list[CitationPattern],
    pattern_type: str,
    top_key: str,
) -> dict[str, Any]:
    filtered = [p for p in patterns if p.pattern_type == pattern_type]
    insights: dict[str, Any] = {f"{p.pattern_name}_frequency": p.frequency for p in filtered}
    if filtered:
        best = max(filtered, key=lambda p: p.frequency)
        if best.frequency > 0:
            insights[top_key] = best.pattern_name
    return insights


class ContentStructureAnalyzer:
    def analyze(self, results: list[AIQueryResult]) -> list[CitationPattern]:
        if not results:
            return self._empty_patterns()

        counts: dict[str, int] = {name: 0 for name, _, _, _ in _CONTENT_RULES}
        for r in results:
            for name, patterns, _, _ in _CONTENT_RULES:
                if _matches_any(r.raw_response, patterns):
                    counts[name] += 1

        total = len(results)
        return [
            CitationPattern(
                pattern_type="content_structure",
                pattern_name=name,
                frequency=counts[name] / total,
                confidence=conf if counts[name] > 0 else 0.0,
                description=desc,
                details={"count": counts[name], "total": total},
            )
            for name, _, conf, desc in _CONTENT_RULES
        ]

    def _empty_patterns(self) -> list[CitationPattern]:
        return [
            CitationPattern(
                pattern_type="content_structure",
                pattern_name=name,
                frequency=0.0,
                confidence=0.0,
                description="",
                details={},
            )
            for name, _, _, _ in _CONTENT_RULES
        ]


class AuthoritySignalAnalyzer:
    def analyze(self, results: list[AIQueryResult]) -> list[CitationPattern]:
        if not results:
            return self._empty_patterns()

        counts: dict[str, int] = {name: 0 for name, _, _, _, _ in _AUTHORITY_RULES}
        extra: dict[str, int] = {name: 0 for name, _, _, _, _ in _AUTHORITY_RULES}

        for r in results:
            for name, patterns, _, _, threshold in _AUTHORITY_RULES:
                match_count = _count_matches(r.raw_response, patterns)
                if match_count >= threshold:
                    counts[name] += 1
                    extra[name] += match_count

        total = len(results)
        return [
            CitationPattern(
                pattern_type="authority_signal",
                pattern_name=name,
                frequency=counts[name] / total,
                confidence=conf if counts[name] > 0 else 0.0,
                description=desc,
                details={"count": counts[name], "total": total, "match_count": extra[name]},
            )
            for name, _, conf, desc, _ in _AUTHORITY_RULES
        ]

    def _empty_patterns(self) -> list[CitationPattern]:
        return [
            CitationPattern(
                pattern_type="authority_signal",
                pattern_name=name,
                frequency=0.0,
                confidence=0.0,
                description="",
                details={},
            )
            for name, _, _, _, _ in _AUTHORITY_RULES
        ]


class CitationFormatAnalyzer:
    def analyze(self, results: list[AIQueryResult]) -> list[CitationPattern]:
        if not results:
            return self._empty_patterns()

        direct_count = 0
        indirect_count = 0
        comparison_count = 0

        for r in results:
            if r.has_brand_citation:
                if _matches_any(r.raw_response, _COMPARISON_PATTERNS) and r.has_competitor_citation:
                    comparison_count += 1
                elif r.brand_context and _matches_any(r.brand_context, _DIRECT_CITATION_PATTERNS):
                    direct_count += 1
                else:
                    indirect_count += 1

        total = len(results)
        return [
            CitationPattern(
                pattern_type="citation_format",
                pattern_name="direct_citation",
                frequency=direct_count / total,
                confidence=0.9 if direct_count > 0 else 0.0,
                description="Direct citation format detected",
                details={"count": direct_count, "total": total},
            ),
            CitationPattern(
                pattern_type="citation_format",
                pattern_name="indirect_citation",
                frequency=indirect_count / total,
                confidence=0.7 if indirect_count > 0 else 0.0,
                description="Indirect citation format detected",
                details={"count": indirect_count, "total": total},
            ),
            CitationPattern(
                pattern_type="citation_format",
                pattern_name="comparison_citation",
                frequency=comparison_count / total,
                confidence=0.85 if comparison_count > 0 else 0.0,
                description="Comparison citation format detected",
                details={"count": comparison_count, "total": total},
            ),
        ]

    def _empty_patterns(self) -> list[CitationPattern]:
        return [
            CitationPattern(
                pattern_type="citation_format",
                pattern_name=name,
                frequency=0.0,
                confidence=0.0,
                description="",
                details={},
            )
            for name in ("direct_citation", "indirect_citation", "comparison_citation")
        ]


class EnginePreferenceAnalyzer:
    def analyze(self, results: list[AIQueryResult]) -> dict[str, dict[str, Any]]:
        if not results:
            return {}

        engine_data: dict[str, dict[str, Any]] = {}

        for r in results:
            engine_name = r.engine_type.value
            if engine_name not in engine_data:
                engine_data[engine_name] = {
                    "results": [],
                    "citation_positions": [],
                    "format_hits": {"faq": 0, "list": 0, "table": 0},
                }
            entry = engine_data[engine_name]
            entry["results"].append(r)
            if r.has_brand_citation:
                for c in r.citations:
                    entry["citation_positions"].append(c.position)
            if _matches_any(r.raw_response, _FAQ_PATTERNS):
                entry["format_hits"]["faq"] += 1
            if _matches_any(r.raw_response, _LIST_PATTERNS):
                entry["format_hits"]["list"] += 1
            if _matches_any(r.raw_response, _TABLE_PATTERNS):
                entry["format_hits"]["table"] += 1

        prefs: dict[str, dict[str, Any]] = {}
        for engine_name, data in engine_data.items():
            total = len(data["results"])
            cited = sum(1 for r in data["results"] if r.has_brand_citation)
            positions = data["citation_positions"]
            avg_pos = sum(positions) / len(positions) if positions else -1

            prefs[engine_name] = {
                "citation_rate": cited / total if total > 0 else 0.0,
                "avg_citation_position": avg_pos,
                "format_preferences": {
                    fmt: count / total if total > 0 else 0.0
                    for fmt, count in data["format_hits"].items()
                },
            }

        return prefs


class CitationPatternEngine:
    def __init__(self) -> None:
        self.content_analyzer = ContentStructureAnalyzer()
        self.authority_analyzer = AuthoritySignalAnalyzer()
        self.format_analyzer = CitationFormatAnalyzer()
        self.engine_analyzer = EnginePreferenceAnalyzer()

    def analyze(
        self,
        results: list[AIQueryResult],
        brand_id: str,
        query: str,
    ) -> PatternAnalysisReport:
        if not results:
            return PatternAnalysisReport(
                brand_id=brand_id,
                query=query,
                total_results=0,
                patterns=[],
                content_structure_insights={},
                authority_signal_insights={},
                citation_format_insights={},
                engine_preferences={},
                recommendations=[],
            )

        patterns: list[CitationPattern] = []
        patterns.extend(self.content_analyzer.analyze(results))
        patterns.extend(self.authority_analyzer.analyze(results))
        patterns.extend(self.format_analyzer.analyze(results))

        engine_prefs = self.engine_analyzer.analyze(results)

        recommendations = self._generate_recommendations(patterns, engine_prefs)

        return PatternAnalysisReport(
            brand_id=brand_id,
            query=query,
            total_results=len(results),
            patterns=patterns,
            content_structure_insights=_build_type_insights(patterns, "content_structure", "dominant_format"),
            authority_signal_insights=_build_type_insights(patterns, "authority_signal", "strongest_signal"),
            citation_format_insights=_build_type_insights(patterns, "citation_format", "primary_format"),
            engine_preferences=engine_prefs,
            recommendations=recommendations,
        )

    def _generate_recommendations(
        self,
        patterns: list[CitationPattern],
        engine_prefs: dict[str, dict],
    ) -> list[str]:
        recommendations: list[str] = []

        pattern_map = {(p.pattern_type, p.pattern_name): p for p in patterns}
        for ptype, pname, threshold, message in _RECOMMENDATION_RULES:
            p = pattern_map.get((ptype, pname))
            if p and p.frequency < threshold:
                recommendations.append(message)

        for engine_name, prefs in engine_prefs.items():
            if prefs["citation_rate"] < 0.3:
                recommendations.append(
                    f"Low citation rate on {engine_name} ({prefs['citation_rate']:.0%}), "
                    f"consider optimizing content for this engine"
                )

        return recommendations