"""Centralized handbook visual theme — single source of truth.

All colour values, font sizes, spacing, and rendering tokens live here.
Templates, CSS generation, and renderers reference this module instead
of hardcoding visual rules.

Spec source: ISP Handbook Enhancement Guidelines + sample PDF.
"""

from __future__ import annotations

from dataclasses import dataclass, field


# ── Colour palette ──────────────────────────────────────────────

@dataclass(frozen=True)
class Colors:
    """Every colour used in the handbook, named by purpose."""

    heading_blue: str = "#1C75BC"
    heading_green: str = "#1A9970"
    body_text: str = "#000000"
    toc_text: str = "#111111"
    note_red: str = "#C00000"
    link_blue: str = "#1C75BC"
    benefits_header_bg: str = "#00F600"
    benefits_header_fg: str = "#FFFFFF"
    benefit_item_bg: str = "#00FCFC"
    benefit_item_fg: str = "#000000"
    school_info_green: str = "#1A9970"
    table_border: str = "#333333"
    table_header_bg: str = "#E6E6E6"
    table_header_fg: str = "#333333"
    toc_dots: str = "#777777"
    muted: str = "#666666"
    note_bg: str = "#F7F8FA"
    note_border: str = "#BBBBBB"
    page_bg: str = "#FFFFFF"


# ── Typography ──────────────────────────────────────────────────

@dataclass(frozen=True)
class Typography:
    """Font families, sizes, weights, and line-heights."""

    font_family: str = "'Century Gothic', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif"
    font_size_body: str = "10pt"
    font_size_h1: str = "12pt"
    font_size_h2: str = "12pt"
    font_size_h3: str = "10pt"
    font_size_toc_heading: str = "12pt"
    font_size_toc_item: str = "10pt"
    font_size_table: str = "9.5px"
    font_size_programs_table: str = "8.5px"
    font_size_career_list: str = "8.5px"
    font_size_note: str = "9.5px"
    font_size_benefits_header: str = "10.5px"
    font_size_benefit_item: str = "10px"
    font_size_school_name: str = "12pt"
    font_size_summary_label: str = "10.5px"
    font_size_summary_value: str = "9.5px"
    font_size_qualify: str = "10px"
    line_height_body: str = "1.4"
    line_height_heading: str = "1.2"
    line_height_table: str = "1.25"


# ── Spacing / margins ──────────────────────────────────────────

@dataclass(frozen=True)
class Spacing:
    """Page geometry and element margins. All margins: 2.54cm."""

    page_margin_top: str = "2.54cm"
    page_margin_right: str = "2.54cm"
    page_margin_bottom: str = "2.54cm"
    page_margin_left: str = "2.54cm"
    paragraph_margin: str = "2px 0 8px"
    heading_margin_h1: str = "12px 0 6px"
    heading_margin_h2: str = "10px 0 4px"
    list_margin: str = "2px 0 8px 18px"
    note_padding: str = "6px 8px"
    note_margin: str = "6px 0 8px"
    table_margin: str = "6px 0 10px"
    table_cell_padding: str = "5px 6px"
    benefits_margin: str = "4px 0 4px"
    school_top_summary_width: str = "58%"
    school_top_campus_width: str = "42%"


# ── Table column widths ────────────────────────────────────────

@dataclass(frozen=True)
class ProgramTableColumns:
    """Fixed widths for the 5-column programs table."""

    program: str = "22%"
    designation: str = "14%"
    entrance_exam: str = "12%"
    career_pathways: str = "34%"
    funding: str = "18%"


# ── Bullet characters ──────────────────────────────────────────

@dataclass(frozen=True)
class Bullets:
    """Bullet characters used throughout the handbook."""

    primary: str = "\u27A2"        # ➢
    benefit: str = "\u2022"        # •
    career: str = "disc"           # CSS list-style-type for career lists


# ── Render-block type registry ──────────────────────────────────

BLOCK_TYPES = (
    "heading_1",
    "heading_2",
    "paragraph",
    "bullet_list",
    "note",
    "table",
    "enrollment_steps",
    "school_profile",
    "university_summary",
    "toc",
    "cover",
    "full_page_image",
)


# ── Composed theme object ──────────────────────────────────────

@dataclass(frozen=True)
class HandbookTheme:
    """Complete handbook theme — inject into renderers and templates."""

    colors: Colors = field(default_factory=Colors)
    typography: Typography = field(default_factory=Typography)
    spacing: Spacing = field(default_factory=Spacing)
    program_columns: ProgramTableColumns = field(default_factory=ProgramTableColumns)
    bullets: Bullets = field(default_factory=Bullets)

    def css_vars(self) -> dict[str, str]:
        """Flatten theme to CSS custom properties (--hb-*)."""
        v: dict[str, str] = {}
        # Colors
        for fname in Colors.__dataclass_fields__:
            v[f"--hb-{fname.replace('_', '-')}"] = getattr(self.colors, fname)
        # Typography
        v["--hb-font-family"] = self.typography.font_family
        v["--hb-font-size-body"] = self.typography.font_size_body
        v["--hb-font-size-h1"] = self.typography.font_size_h1
        v["--hb-font-size-h2"] = self.typography.font_size_h2
        v["--hb-line-height-body"] = self.typography.line_height_body
        # Spacing
        v["--hb-page-margin-top"] = self.spacing.page_margin_top
        v["--hb-page-margin-right"] = self.spacing.page_margin_right
        v["--hb-page-margin-bottom"] = self.spacing.page_margin_bottom
        v["--hb-page-margin-left"] = self.spacing.page_margin_left
        # Bullet
        v["--hb-bullet-char"] = f'"{self.bullets.primary}"'
        return v


# Module-level singleton
THEME = HandbookTheme()