// css.go — the stylesheet is generated per site: theme colors and the mixed
// per-agent coverage colors become custom properties, one block per scheme.
package main

import (
	"fmt"
	"io"
	"sort"
	"strings"
	texttemplate "text/template"
)

type cssVar struct{ K, V string }

type synCSS struct{ Class, Style, Weight string }

func renderCSS(w io.Writer, site *Site) error {
	css, err := texttemplate.ParseFS(tfs, "assets/style.css.tmpl")
	if err != nil {
		return err
	}
	var unionKeys []string
	seen := map[string]bool{}
	for _, t := range []*Theme{site.Theme, site.Light} {
		for k := range t.Syntax {
			if !seen[k] {
				seen[k] = true
				unionKeys = append(unionKeys, k)
			}
		}
	}
	sort.Strings(unionKeys)
	masks := site.masks()
	themeVars := func(t *Theme) []cssVar {
		vars := []cssVar{
			{"--bg", t.Bg}, {"--fg", t.Fg}, {"--panel", t.Panel}, {"--border", t.Border},
			{"--ln", t.LineNo}, {"--muted", t.Muted}, {"--accent", t.Accent},
			{"--note", t.Note}, {"--hover", t.Hover},
		}
		for _, k := range unionKeys {
			if s, ok := t.Syntax[k]; ok && s.Color != "" {
				vars = append(vars, cssVar{"--s-" + strings.ReplaceAll(k, ".", "-"), s.Color})
			}
		}
		for _, m := range masks {
			vars = append(vars, cssVar{fmt.Sprintf("--am%d", m), site.maskColor(t, m)})
		}
		return vars
	}
	var syn []synCSS
	for _, k := range unionKeys {
		s := synCSS{Class: strings.ReplaceAll(k, ".", "-")}
		if v, ok := site.Theme.Syntax[k]; ok {
			if v.FontStyle != nil {
				s.Style = *v.FontStyle
			}
			if v.FontWeight != nil {
				s.Weight = fmt.Sprintf("%.0f", *v.FontWeight)
			}
		}
		syn = append(syn, s)
	}
	return css.Execute(w, map[string]any{
		"DarkName": site.Theme.Name, "LightName": site.Light.Name,
		"DarkVars": themeVars(site.Theme), "LightVars": themeVars(site.Light),
		"Syntax": syn, "MaskList": masks,
	})
}