package processing

import (
	"fmt"
	"regexp"
	"strings"

	"github.com/descrybe/descrybe-v2/apps/api/internal/aiprompts"
)

// Legacy A1 (generator.php process_product_description) used the category Prompt
// as the entire USER message after substituting OPIS IZDELKA / STARO IME IZDELKA,
// with a one-line Slovenian copywriter SYSTEM message, then parsed <name> and
// <metaDescription> from the HTML reply. v2 must recreate that GPT-predloga
// dominance while keeping JSON {"name","description","meta_*","attrs"}.

// {{language}} renders an English label ("Slovenian"), so both templates name the
// language after a colon instead of inflecting it — legacy "v Slovenščini" read as
// "v Slovenian" and put a grammatical error in front of every A1 prompt.
const a1StyleEnhanceSystemTemplateSL = `Si tekstopisec, ki piše opise izdelkov v tem jeziku: {{language}}.
Rules:
- Reply with ONLY JSON (no markdown)
- Schema: {"name":"string","description":"string","meta_title":"string","meta_description":"string","attrs":{}}
- Obey the GPT predloga in the user message step by step (same behavior as legacy A1 category Prompt)
- "name" follows the <name> Title formula — never copy Staro_ime_izdelka unchanged when the formula asks for a new name
- "description" is ONE HTML string covering each GPT predloga body section in order (tags matching type: h1/h2/h3/h4, p, ul) — do NOT wrap the reply in <name> or <metaDescription> tags
- "meta_title" and "meta_description" are plain SEO text from the meta / <metaDescription> formula (never HTML body)
- attrs: only Allowed attribute keys when listed; fill from evidence only; omit unknowns
{{brand_voice}}`

// a1StyleEnhanceSystemTemplateEN is the same contract for the English
// platform-default formulas, matching the English scaffolding in a1StyleLabelsEN.
const a1StyleEnhanceSystemTemplateEN = `You are a copywriter who writes product descriptions in this language: {{language}}.
Rules:
- Reply with ONLY JSON (no markdown)
- Schema: {"name":"string","description":"string","meta_title":"string","meta_description":"string","attrs":{}}
- Obey the product template in the user message step by step
- "name" follows the <name> formula — never copy Old_product_name unchanged when the formula asks for a new name
- "description" is ONE HTML string covering each product template body section in order (tags matching type: h1/h2/h3/h4, p, ul) — do NOT wrap the reply in <name> or <metaDescription> tags
- "meta_title" and "meta_description" are plain SEO text from the meta / <metaDescription> formula (never HTML body)
- Use only the supplied Old_product_name, Old_product_description, Category and Attrs as facts; never invent specifications
- attrs: only Allowed attribute keys when listed; fill from evidence only; omit unknowns
{{brand_voice}}`

var (
	reLegacyNameCapture = regexp.MustCompile(`(?is)<\s*name\s*>\s*(.*?)\s*<\s*/\s*name\s*>`)
	reLegacyMetaCapture = regexp.MustCompile(`(?is)<\s*metaDescription\s*>\s*(.*?)\s*<\s*/\s*metaDescription\s*>`)
	reLegacyNameStrip   = regexp.MustCompile(`(?is)<\s*name\s*>.*?<\s*/\s*name\s*>`)
	reLegacyMetaStrip   = regexp.MustCompile(`(?is)<\s*metaDescription\s*>.*?<\s*/\s*metaDescription\s*>`)
)

// categoryUsesA1StyleFormula is true when the category carries Title/Description/Meta
// formula content that must drive enhance like legacy generator.php (not soft overlay).
func categoryUsesA1StyleFormula(catPrompt string, titleTemplate, descriptionTemplate any) bool {
	if FormatTitleFormulaConstraint(titleTemplate) != "" {
		return true
	}
	if FormatDescriptionFormulaConstraint(descriptionTemplate) != "" {
		return true
	}
	if FormatMetaFormulaConstraint(descriptionTemplate) != "" {
		return true
	}
	if FormatTitleSectionConstraint(catPrompt) != "" {
		return true
	}
	if aiprompts.CategoryTitlePromptRequiresRewrite(catPrompt) {
		return true
	}
	descBody := aiprompts.DescriptionSectionInstructions(catPrompt)
	if descBody != "" && aiprompts.LegacyHTMLFormulaPresent(descBody) {
		return true
	}
	return strings.TrimSpace(aiprompts.MetaSectionInstructions(catPrompt)) != ""
}

// buildA1StyleEnhanceUserTemplate rebuilds the legacy GPT-predloga user message
// (Title → <name>, Meta → <metaDescription>, Description HTML blocks) plus product
// evidence placeholders, asking for JSON field mapping.
func buildA1StyleEnhanceUserTemplate(catPrompt string, titleTemplate, descriptionTemplate any, omitSEOMeta bool) (string, bool) {
	titleInstr := strings.TrimSpace(aiprompts.TitleSectionInstructions(catPrompt))
	if titleInstr == "" || isBuiltInTitleRoleBoilerplate(titleInstr) {
		titleInstr = ""
	}
	if titleInstr == "" {
		if block := FormatTitleFormulaConstraint(titleTemplate); block != "" {
			titleInstr = block
		}
	}

	descBody := strings.TrimSpace(aiprompts.DescriptionSectionInstructions(catPrompt))
	if descBody != "" && !aiprompts.LegacyHTMLFormulaPresent(descBody) {
		// Free-form description instructions without HTML — keep as a p-block cue.
		descBody = "<p>{" + descBody + "}</p>"
	}
	if descBody == "" {
		descBody = FormatDescriptionFormulaAsLegacyHTML(descriptionTemplate)
	}

	metaInstr := strings.TrimSpace(aiprompts.MetaSectionInstructions(catPrompt))
	if metaInstr == "" {
		mt, md := parseMetaFormulaInstructions(descriptionTemplate)
		switch {
		case mt != "" && md != "":
			metaInstr = "meta_title: " + mt + "\nmeta_description: " + md
		case md != "":
			metaInstr = md
		case mt != "":
			metaInstr = mt
		}
	}

	var predloga strings.Builder
	if titleInstr != "" {
		fmt.Fprintf(&predloga, "<name>{%s}</name>\n", collapseLegacyInstr(titleInstr))
	}
	if !omitSEOMeta && metaInstr != "" {
		fmt.Fprintf(&predloga, "<metaDescription>{%s}</metaDescription>\n", collapseLegacyInstr(metaInstr))
	}
	if descBody != "" {
		predloga.WriteString(strings.TrimSpace(descBody))
		predloga.WriteByte('\n')
	}

	body := strings.TrimSpace(predloga.String())
	slovenian := reSlovenianFormulaCue.MatchString(body)
	l := a1StyleLabelsEN
	if slovenian {
		l = a1StyleLabelsSL
	}

	var b strings.Builder
	fmt.Fprintf(&b, "%s\n\n", l.intro)
	fmt.Fprintf(&b, "%s: {{name}}\n", l.oldName)
	fmt.Fprintf(&b, "%s: {{description}}\n", l.oldDesc)
	fmt.Fprintf(&b, "%s: {{category}}\n", l.category)
	b.WriteString("Attrs: {{attrs}}\n\n")
	fmt.Fprintf(&b, "%s\n%s\n\n", l.useTemplate, l.followTemplate)
	fmt.Fprintf(&b, "%s\n\n", l.templateHeader)
	b.WriteString(body)
	b.WriteString("\n\n")
	fmt.Fprintf(&b, "%s\n", l.replyHeader)
	fmt.Fprintf(&b, "%s\n", l.nameRule)
	fmt.Fprintf(&b, "%s\n", l.descRule)
	if !omitSEOMeta {
		fmt.Fprintf(&b, "%s\n", l.metaRule)
	}
	b.WriteString(l.attrsRule)

	// Free-form category overlay (no role markers) — keep as extra guidance like
	// soft "Category guidance" did, without replacing the template.
	extra := strings.TrimSpace(catPrompt)
	if extra != "" &&
		!aiprompts.CategoryEnhanceHasRoleSections(extra) &&
		!aiprompts.IsLegacyCombinedEnhancePrompt(extra) {
		fmt.Fprintf(&b, "\n\n%s\n", l.extraHeader)
		b.WriteString(extra)
	}
	return strings.TrimSpace(b.String()), slovenian
}

// a1StyleLabels are the scaffolding strings around a category formula: how the
// supplied variables are labelled and how the reply is framed.
type a1StyleLabels struct {
	intro          string
	oldName        string
	oldDesc        string
	category       string
	useTemplate    string
	followTemplate string
	templateHeader string
	replyHeader    string
	nameRule       string
	descRule       string
	metaRule       string
	attrsRule      string
	extraHeader    string
}

var a1StyleLabelsSL = a1StyleLabels{
	intro:          "Ustvari nov opis izdelka v tem jeziku: {{language}}, z naslednjimi spremenljivkami:",
	oldName:        "Staro_ime_izdelka",
	oldDesc:        "Star_opis_izdelka",
	category:       "Kategorija",
	useTemplate:    "Uporabi spodnjo GPT predlogo.",
	followTemplate: "Sledi tej GPT predlogi stavek po stavek in sestavi nov opis izdelka.",
	templateHeader: "GPT predloga:",
	replyHeader:    "Odgovori SAMO z enim JSON objektom:",
	nameRule:       `- "name" = rezultat <name> formule (novo ime; ne kopiraj Staro_ime_izdelka, če formula zahteva novo ime)`,
	descRule:       `- "description" = HTML telo po GPT predlogi (vsi razdelki po vrsti), BREZ <name>/<metaDescription> tagov`,
	metaRule:       `- "meta_title" / "meta_description" = plain SEO po meta / <metaDescription> formuli`,
	attrsRule:      `- "attrs" = atributi (samo Allowed attribute keys, če so navedeni)`,
	extraHeader:    "Dodatna kategorijska navodila:",
}

var a1StyleLabelsEN = a1StyleLabels{
	intro:          "Create a new product description in {{language}} using the following variables:",
	oldName:        "Old_product_name",
	oldDesc:        "Old_product_description",
	category:       "Category",
	useTemplate:    "Use the product template below.",
	followTemplate: "Follow this product template sentence by sentence and compose a new product description.",
	templateHeader: "Product template:",
	replyHeader:    "Reply with ONE JSON object only:",
	nameRule:       `- "name" = the result of the <name> formula (a new name; do not copy Old_product_name when the formula asks for a new one)`,
	descRule:       `- "description" = the HTML body per the product template (every section in order), WITHOUT <name>/<metaDescription> tags`,
	metaRule:       `- "meta_title" / "meta_description" = plain SEO text per the meta / <metaDescription> formula`,
	attrsRule:      `- "attrs" = attributes (only Allowed attribute keys when listed)`,
	extraHeader:    "Additional category instructions:",
}

// reSlovenianFormulaCue keeps the scaffolding in the same language the formula
// speaks. A1's legacy formulas refer to "Novo ime izdelka" and were written against
// the Slovenian variable labels in generator.php, so those keep the Slovenian
// frame; the English platform defaults get the English one. Output language is set
// by {{language}} in the system prompt either way.
var reSlovenianFormulaCue = regexp.MustCompile(`(?i)novo[ _]ime[ _]izdelka|napiši|napisi|izpostavi|izdelka|znamka`)

func collapseLegacyInstr(s string) string {
	s = strings.TrimSpace(s)
	s = strings.ReplaceAll(s, "\r\n", "\n")
	for strings.Contains(s, "\n\n\n") {
		s = strings.ReplaceAll(s, "\n\n\n", "\n\n")
	}
	return s
}

// FormatDescriptionFormulaAsLegacyHTML turns description_template sections back into
// the A1 HTML GPT-predloga shape (<H2>{…}</H2><p>{…}</p><ul>…).
func FormatDescriptionFormulaAsLegacyHTML(template any) string {
	sections, ok := parseDescriptionFormulaSections(template)
	if !ok || len(sections) == 0 {
		return ""
	}
	var b strings.Builder
	for _, s := range sections {
		typ := strings.ToLower(strings.TrimSpace(s.Type))
		instr := strings.TrimSpace(s.Instructions)
		if instr == "" {
			instr = typ
		}
		switch typ {
		case "h1", "h2", "h3", "h4":
			fmt.Fprintf(&b, "<%s>{%s}</%s>", strings.ToUpper(typ), instr, strings.ToUpper(typ))
		case "ul", "ol", "li":
			fmt.Fprintf(&b, "<b>{Tehnične specifikacije}</b><ul><li>{%s}</li></ul>", instr)
		case "p", "":
			fmt.Fprintf(&b, "<p>{%s}</p>", instr)
		default:
			fmt.Fprintf(&b, "<p>{%s}</p>", instr)
		}
	}
	return b.String()
}

// ParseLegacyEnhanceHTML extracts name / metaDescription / body HTML from a legacy
// A1 model reply (generator.php preg_match on <name> / <metaDescription>).
func ParseLegacyEnhanceHTML(raw string) (name, metaDescription, bodyHTML string, ok bool) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return "", "", "", false
	}
	if m := reLegacyNameCapture.FindStringSubmatch(raw); len(m) == 2 {
		name = strings.TrimSpace(m[1])
	}
	if m := reLegacyMetaCapture.FindStringSubmatch(raw); len(m) == 2 {
		metaDescription = strings.TrimSpace(m[1])
	}
	body := reLegacyNameStrip.ReplaceAllString(raw, "")
	body = reLegacyMetaStrip.ReplaceAllString(body, "")
	bodyHTML = strings.TrimSpace(body)
	ok = name != "" || metaDescription != "" || (bodyHTML != "" && bodyHTML != raw)
	return name, metaDescription, bodyHTML, ok
}

// applyLegacyEnhanceTagFallback fills empty JSON fields from embedded legacy tags
// and strips <name>/<metaDescription> wrappers from description (feed.php behavior).
func applyLegacyEnhanceTagFallback(obj map[string]any, rawText string) {
	if obj == nil {
		return
	}
	name := strings.TrimSpace(fmt.Sprint(obj["name"]))
	desc := strings.TrimSpace(fmt.Sprint(obj["description"]))
	metaTitle := strings.TrimSpace(fmt.Sprint(obj["meta_title"]))
	metaDesc := strings.TrimSpace(fmt.Sprint(obj["meta_description"]))
	if metaDesc == "" {
		metaDesc = strings.TrimSpace(fmt.Sprint(obj["metaDescription"]))
	}

	src := desc
	if src == "" || src == "<nil>" {
		src = rawText
	}
	ln, lm, lb, ok := ParseLegacyEnhanceHTML(src)
	if !ok {
		ln2, lm2, lb2, ok2 := ParseLegacyEnhanceHTML(rawText)
		if ok2 {
			ln, lm, lb, ok = ln2, lm2, lb2, true
		}
	}
	if !ok {
		// Still strip tags if description accidentally includes them.
		if desc != "" && desc != "<nil>" {
			cleaned := reLegacyNameStrip.ReplaceAllString(desc, "")
			cleaned = reLegacyMetaStrip.ReplaceAllString(cleaned, "")
			cleaned = strings.TrimSpace(cleaned)
			if cleaned != "" && cleaned != desc {
				obj["description"] = cleaned
			}
		}
		return
	}
	if (name == "" || name == "<nil>") && ln != "" {
		obj["name"] = ln
	}
	if (metaDesc == "" || metaDesc == "<nil>") && lm != "" {
		obj["meta_description"] = lm
	}
	if (metaTitle == "" || metaTitle == "<nil>") && ln != "" {
		// Legacy only had metaDescription; seed meta_title from new name when empty.
		obj["meta_title"] = ln
	}
	if lb != "" {
		obj["description"] = lb
	}
}