"""
Agent 1: Token Extractor
Design System Extractor v2

Persona: Meticulous Design Archaeologist

Responsibilities:
- Crawl pages at specified viewport
- Extract computed styles from all elements
- Collect colors, typography, spacing, radius, shadows
- Track frequency and context for each token
"""

import asyncio
import re
from typing import Optional, Callable
from datetime import datetime
from collections import defaultdict

from playwright.async_api import async_playwright, Browser, Page, BrowserContext

from core.token_schema import (
    Viewport,
    ExtractedTokens,
    ColorToken,
    TypographyToken,
    SpacingToken,
    RadiusToken,
    ShadowToken,
    FontFamily,
    TokenSource,
    Confidence,
)
from core.color_utils import (
    normalize_hex,
    parse_color,
    get_contrast_with_white,
    get_contrast_with_black,
    check_wcag_compliance,
)
from config.settings import get_settings


class TokenExtractor:
    """
    Extracts design tokens from web pages.
    
    This is the second part of Agent 1's job — after pages are confirmed,
    we crawl and extract all CSS values.
    """
    
    def __init__(self, viewport: Viewport = Viewport.DESKTOP):
        self.settings = get_settings()
        self.viewport = viewport
        self.browser: Optional[Browser] = None
        self.context: Optional[BrowserContext] = None
        
        # Token collection
        self.colors: dict[str, ColorToken] = {}
        self.typography: dict[str, TypographyToken] = {}
        self.spacing: dict[str, SpacingToken] = {}
        self.radius: dict[str, RadiusToken] = {}
        self.shadows: dict[str, ShadowToken] = {}
        
        # Font tracking
        self.font_families: dict[str, FontFamily] = {}
        
        # Statistics
        self.total_elements = 0
        self.errors: list[str] = []
        self.warnings: list[str] = []
    
    async def __aenter__(self):
        """Async context manager entry."""
        await self._init_browser()
        return self
    
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        """Async context manager exit."""
        await self._close_browser()
    
    async def _init_browser(self):
        """Initialize Playwright browser."""
        playwright = await async_playwright().start()
        self.browser = await playwright.chromium.launch(
            headless=self.settings.browser.headless
        )
        
        # Set viewport based on extraction mode
        if self.viewport == Viewport.DESKTOP:
            width = self.settings.viewport.desktop_width
            height = self.settings.viewport.desktop_height
        else:
            width = self.settings.viewport.mobile_width
            height = self.settings.viewport.mobile_height
        
        self.context = await self.browser.new_context(
            viewport={"width": width, "height": height},
            user_agent="Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36"
        )
    
    async def _close_browser(self):
        """Close browser and cleanup."""
        if self.context:
            await self.context.close()
        if self.browser:
            await self.browser.close()
    
    async def _scroll_page(self, page: Page):
        """Scroll page to load lazy content."""
        await page.evaluate("""
            async () => {
                const delay = ms => new Promise(resolve => setTimeout(resolve, ms));
                const height = document.body.scrollHeight;
                const step = window.innerHeight;
                
                for (let y = 0; y < height; y += step) {
                    window.scrollTo(0, y);
                    await delay(100);
                }
                
                // Scroll back to top
                window.scrollTo(0, 0);
            }
        """)
        
        # Wait for network idle after scrolling
        await page.wait_for_load_state("networkidle", timeout=self.settings.browser.network_idle_timeout)
    
    async def _extract_styles_from_page(self, page: Page) -> dict:
        """
        Extract computed styles from all elements on the page.
        
        This is the core extraction logic — we get getComputedStyle for every element.
        """
        styles_data = await page.evaluate("""
            () => {
                const elements = document.querySelectorAll('*');
                const results = {
                    colors: [],
                    typography: [],
                    spacing: [],
                    radius: [],
                    shadows: [],
                    elements_count: elements.length,
                };
                
                const colorProperties = [
                    'color', 'background-color', 'border-color',
                    'border-top-color', 'border-right-color', 
                    'border-bottom-color', 'border-left-color',
                    'outline-color', 'text-decoration-color',
                ];
                
                const spacingProperties = [
                    'margin-top', 'margin-right', 'margin-bottom', 'margin-left',
                    'padding-top', 'padding-right', 'padding-bottom', 'padding-left',
                    'gap', 'row-gap', 'column-gap',
                ];
                
                elements.forEach(el => {
                    const tag = el.tagName.toLowerCase();
                    const styles = window.getComputedStyle(el);
                    
                    // Skip invisible elements
                    if (styles.display === 'none' || styles.visibility === 'hidden') {
                        return;
                    }
                    
                    // --- COLORS ---
                    colorProperties.forEach(prop => {
                        const value = styles.getPropertyValue(prop);
                        if (value && value !== 'rgba(0, 0, 0, 0)' && value !== 'transparent') {
                            results.colors.push({
                                value: value,
                                property: prop,
                                element: tag,
                                context: prop.includes('background') ? 'background' : 
                                        prop.includes('border') ? 'border' : 'text',
                            });
                        }
                    });
                    
                    // --- TYPOGRAPHY ---
                    const fontFamily = styles.getPropertyValue('font-family');
                    const fontSize = styles.getPropertyValue('font-size');
                    const fontWeight = styles.getPropertyValue('font-weight');
                    const lineHeight = styles.getPropertyValue('line-height');
                    const letterSpacing = styles.getPropertyValue('letter-spacing');
                    
                    if (fontSize && fontFamily) {
                        results.typography.push({
                            fontFamily: fontFamily,
                            fontSize: fontSize,
                            fontWeight: fontWeight,
                            lineHeight: lineHeight,
                            letterSpacing: letterSpacing,
                            element: tag,
                        });
                    }
                    
                    // --- SPACING ---
                    spacingProperties.forEach(prop => {
                        const value = styles.getPropertyValue(prop);
                        if (value && value !== '0px' && value !== 'auto' && value !== 'normal') {
                            const px = parseFloat(value);
                            if (!isNaN(px) && px > 0 && px < 500) {
                                results.spacing.push({
                                    value: value,
                                    valuePx: Math.round(px),
                                    property: prop,
                                    context: prop.includes('margin') ? 'margin' : 
                                            prop.includes('padding') ? 'padding' : 'gap',
                                });
                            }
                        }
                    });
                    
                    // --- BORDER RADIUS ---
                    const radiusProps = [
                        'border-radius', 'border-top-left-radius', 
                        'border-top-right-radius', 'border-bottom-left-radius',
                        'border-bottom-right-radius',
                    ];
                    
                    radiusProps.forEach(prop => {
                        const value = styles.getPropertyValue(prop);
                        if (value && value !== '0px') {
                            results.radius.push({
                                value: value,
                                element: tag,
                            });
                        }
                    });
                    
                    // --- BOX SHADOW ---
                    const shadow = styles.getPropertyValue('box-shadow');
                    if (shadow && shadow !== 'none') {
                        results.shadows.push({
                            value: shadow,
                            element: tag,
                        });
                    }
                });
                
                return results;
            }
        """)
        
        return styles_data
    
    def _process_color(self, color_data: dict) -> Optional[str]:
        """Process and normalize a color value."""
        value = color_data.get("value", "")
        
        # Parse and normalize
        parsed = parse_color(value)
        if not parsed:
            return None
        
        return parsed.hex
    
    def _aggregate_colors(self, raw_colors: list[dict]):
        """Aggregate color data from extraction."""
        for color_data in raw_colors:
            hex_value = self._process_color(color_data)
            if not hex_value:
                continue
            
            if hex_value not in self.colors:
                # Calculate contrast ratios
                contrast_white = get_contrast_with_white(hex_value)
                contrast_black = get_contrast_with_black(hex_value)
                compliance = check_wcag_compliance(hex_value, "#ffffff")
                
                self.colors[hex_value] = ColorToken(
                    value=hex_value,
                    frequency=0,
                    contexts=[],
                    elements=[],
                    css_properties=[],
                    contrast_white=round(contrast_white, 2),
                    contrast_black=round(contrast_black, 2),
                    wcag_aa_large_text=compliance["aa_large_text"],
                    wcag_aa_small_text=compliance["aa_normal_text"],
                )
            
            # Update frequency and context
            token = self.colors[hex_value]
            token.frequency += 1
            
            context = color_data.get("context", "")
            if context and context not in token.contexts:
                token.contexts.append(context)
            
            element = color_data.get("element", "")
            if element and element not in token.elements:
                token.elements.append(element)
            
            prop = color_data.get("property", "")
            if prop and prop not in token.css_properties:
                token.css_properties.append(prop)
    
    def _aggregate_typography(self, raw_typography: list[dict]):
        """Aggregate typography data from extraction."""
        for typo_data in raw_typography:
            # Create unique key
            font_family = typo_data.get("fontFamily", "")
            font_size = typo_data.get("fontSize", "")
            font_weight = typo_data.get("fontWeight", "400")
            line_height = typo_data.get("lineHeight", "normal")
            
            key = f"{font_size}|{font_weight}|{font_family[:50]}"
            
            if key not in self.typography:
                # Parse font size to px
                font_size_px = None
                if font_size.endswith("px"):
                    try:
                        font_size_px = float(font_size.replace("px", ""))
                    except ValueError:
                        pass
                
                # Parse line height
                line_height_computed = None
                if line_height and line_height != "normal":
                    if line_height.endswith("px") and font_size_px:
                        try:
                            lh_px = float(line_height.replace("px", ""))
                            line_height_computed = round(lh_px / font_size_px, 2)
                        except ValueError:
                            pass
                    else:
                        try:
                            line_height_computed = float(line_height)
                        except ValueError:
                            pass
                
                self.typography[key] = TypographyToken(
                    font_family=font_family.split(",")[0].strip().strip('"\''),
                    font_size=font_size,
                    font_size_px=font_size_px,
                    font_weight=int(font_weight) if font_weight.isdigit() else 400,
                    line_height=line_height,
                    line_height_computed=line_height_computed,
                    letter_spacing=typo_data.get("letterSpacing"),
                    frequency=0,
                    elements=[],
                )
            
            # Update
            token = self.typography[key]
            token.frequency += 1
            
            element = typo_data.get("element", "")
            if element and element not in token.elements:
                token.elements.append(element)
            
            # Track font families
            primary_font = token.font_family
            if primary_font not in self.font_families:
                self.font_families[primary_font] = FontFamily(
                    name=primary_font,
                    fallbacks=[f.strip().strip('"\'') for f in font_family.split(",")[1:]],
                    frequency=0,
                )
            self.font_families[primary_font].frequency += 1
    
    def _aggregate_spacing(self, raw_spacing: list[dict]):
        """Aggregate spacing data from extraction."""
        for space_data in raw_spacing:
            value = space_data.get("value", "")
            value_px = space_data.get("valuePx", 0)
            
            key = str(value_px)
            
            if key not in self.spacing:
                self.spacing[key] = SpacingToken(
                    value=f"{value_px}px",
                    value_px=value_px,
                    frequency=0,
                    contexts=[],
                    properties=[],
                    fits_base_4=value_px % 4 == 0,
                    fits_base_8=value_px % 8 == 0,
                )
            
            token = self.spacing[key]
            token.frequency += 1
            
            context = space_data.get("context", "")
            if context and context not in token.contexts:
                token.contexts.append(context)
            
            prop = space_data.get("property", "")
            if prop and prop not in token.properties:
                token.properties.append(prop)
    
    def _aggregate_radius(self, raw_radius: list[dict]):
        """Aggregate border radius data."""
        for radius_data in raw_radius:
            value = radius_data.get("value", "")
            
            # Normalize to simple format
            # "8px 8px 8px 8px" -> "8px"
            parts = value.split()
            if len(set(parts)) == 1:
                value = parts[0]
            
            if value not in self.radius:
                value_px = None
                if value.endswith("px"):
                    try:
                        value_px = int(float(value.replace("px", "")))
                    except ValueError:
                        pass
                
                self.radius[value] = RadiusToken(
                    value=value,
                    value_px=value_px,
                    frequency=0,
                    elements=[],
                    fits_base_4=value_px % 4 == 0 if value_px else False,
                    fits_base_8=value_px % 8 == 0 if value_px else False,
                )
            
            token = self.radius[value]
            token.frequency += 1
            
            element = radius_data.get("element", "")
            if element and element not in token.elements:
                token.elements.append(element)
    
    def _aggregate_shadows(self, raw_shadows: list[dict]):
        """Aggregate box shadow data."""
        for shadow_data in raw_shadows:
            value = shadow_data.get("value", "")
            
            if value not in self.shadows:
                self.shadows[value] = ShadowToken(
                    value=value,
                    frequency=0,
                    elements=[],
                )
            
            token = self.shadows[value]
            token.frequency += 1
            
            element = shadow_data.get("element", "")
            if element and element not in token.elements:
                token.elements.append(element)
    
    def _calculate_confidence(self, frequency: int) -> Confidence:
        """Calculate confidence level based on frequency."""
        if frequency >= 10:
            return Confidence.HIGH
        elif frequency >= 3:
            return Confidence.MEDIUM
        return Confidence.LOW
    
    def _detect_spacing_base(self) -> Optional[int]:
        """Detect the base spacing unit (4 or 8)."""
        fits_4 = sum(1 for s in self.spacing.values() if s.fits_base_4)
        fits_8 = sum(1 for s in self.spacing.values() if s.fits_base_8)
        
        total = len(self.spacing)
        if total == 0:
            return None
        
        # If 80%+ values fit base 8, use 8
        if fits_8 / total >= 0.8:
            return 8
        # If 80%+ values fit base 4, use 4
        elif fits_4 / total >= 0.8:
            return 4
        
        return None
    
    async def extract(
        self,
        pages: list[str],
        progress_callback: Optional[Callable[[float], None]] = None
    ) -> ExtractedTokens:
        """
        Extract tokens from a list of pages.
        
        Args:
            pages: List of URLs to crawl
            progress_callback: Optional callback for progress updates
        
        Returns:
            ExtractedTokens with all discovered tokens
        """
        start_time = datetime.now()
        pages_crawled = []
        
        async with self:
            for i, url in enumerate(pages):
                try:
                    page = await self.context.new_page()
                    
                    # Navigate with fallback strategy
                    try:
                        await page.goto(
                            url,
                            wait_until="domcontentloaded",
                            timeout=60000  # 60 seconds
                        )
                        # Wait for JS to render
                        await page.wait_for_timeout(2000)
                    except Exception as nav_error:
                        # Fallback to load event
                        try:
                            await page.goto(
                                url,
                                wait_until="load",
                                timeout=60000
                            )
                            await page.wait_for_timeout(3000)
                        except Exception:
                            self.warnings.append(f"Slow load for {url}, extracting partial content")
                    
                    # Scroll to load lazy content
                    await self._scroll_page(page)
                    
                    # Extract styles
                    styles = await self._extract_styles_from_page(page)
                    
                    # Aggregate
                    self._aggregate_colors(styles.get("colors", []))
                    self._aggregate_typography(styles.get("typography", []))
                    self._aggregate_spacing(styles.get("spacing", []))
                    self._aggregate_radius(styles.get("radius", []))
                    self._aggregate_shadows(styles.get("shadows", []))
                    
                    self.total_elements += styles.get("elements_count", 0)
                    pages_crawled.append(url)
                    
                    await page.close()
                    
                    # Progress callback
                    if progress_callback:
                        progress_callback((i + 1) / len(pages))
                    
                    # Rate limiting
                    await asyncio.sleep(self.settings.crawl.crawl_delay_ms / 1000)
                    
                except Exception as e:
                    self.errors.append(f"Error extracting {url}: {str(e)}")
        
        # Calculate confidence for all tokens
        for token in self.colors.values():
            token.confidence = self._calculate_confidence(token.frequency)
        for token in self.typography.values():
            token.confidence = self._calculate_confidence(token.frequency)
        for token in self.spacing.values():
            token.confidence = self._calculate_confidence(token.frequency)
        
        # Detect spacing base
        spacing_base = self._detect_spacing_base()
        
        # Mark outliers in spacing
        if spacing_base:
            for token in self.spacing.values():
                if spacing_base == 8 and not token.fits_base_8:
                    token.is_outlier = True
                elif spacing_base == 4 and not token.fits_base_4:
                    token.is_outlier = True
        
        # Determine primary font
        if self.font_families:
            primary_font = max(self.font_families.values(), key=lambda f: f.frequency)
            primary_font.usage = "primary"
        
        # Build result
        end_time = datetime.now()
        duration_ms = int((end_time - start_time).total_seconds() * 1000)
        
        return ExtractedTokens(
            viewport=self.viewport,
            source_url=pages[0] if pages else "",
            pages_crawled=pages_crawled,
            colors=list(self.colors.values()),
            typography=list(self.typography.values()),
            spacing=list(self.spacing.values()),
            radius=list(self.radius.values()),
            shadows=list(self.shadows.values()),
            font_families=list(self.font_families.values()),
            spacing_base=spacing_base,
            extraction_timestamp=start_time,
            extraction_duration_ms=duration_ms,
            total_elements_analyzed=self.total_elements,
            unique_colors=len(self.colors),
            unique_font_sizes=len(set(t.font_size for t in self.typography.values())),
            unique_spacing_values=len(self.spacing),
            errors=self.errors,
            warnings=self.warnings,
        )


# =============================================================================
# CONVENIENCE FUNCTIONS
# =============================================================================

async def extract_from_pages(
    pages: list[str],
    viewport: Viewport = Viewport.DESKTOP
) -> ExtractedTokens:
    """Convenience function to extract tokens from pages."""
    extractor = TokenExtractor(viewport=viewport)
    return await extractor.extract(pages)


async def extract_both_viewports(pages: list[str]) -> tuple[ExtractedTokens, ExtractedTokens]:
    """Extract tokens from both desktop and mobile viewports."""
    desktop_extractor = TokenExtractor(viewport=Viewport.DESKTOP)
    mobile_extractor = TokenExtractor(viewport=Viewport.MOBILE)
    
    desktop_result = await desktop_extractor.extract(pages)
    mobile_result = await mobile_extractor.extract(pages)
    
    return desktop_result, mobile_result