package company

import (
	"context"
	"errors"
	"strings"
	"time"

	"github.com/descrybe/descrybe-v2/apps/api/internal/security"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

// BrandKit stores company brand voice, guidelines, and visual identity.
type BrandKit struct {
	CompanyID      uuid.UUID `json:"company_id"`
	VoiceTone      string    `json:"voice_tone"`
	Dos            []string  `json:"dos"`
	Donts          []string  `json:"donts"`
	PrimaryColor   string    `json:"primary_color"`
	SecondaryColor string    `json:"secondary_color"`
	LogoURL        string    `json:"logo_url"`
	PreferredTerms []string  `json:"preferred_terms"`
	UpdatedAt      time.Time `json:"updated_at"`
}

// EmptyBrand returns a zero kit for a company (no row yet).
func EmptyBrand(companyID uuid.UUID) BrandKit {
	return BrandKit{
		CompanyID:      companyID,
		Dos:            []string{},
		Donts:          []string{},
		PreferredTerms: []string{},
	}
}

// LoadBrand returns the company brand kit, or an empty kit when none is saved.
func LoadBrand(ctx context.Context, pool *pgxpool.Pool, companyID uuid.UUID) (BrandKit, error) {
	var b BrandKit
	err := pool.QueryRow(ctx, `
		SELECT company_id, voice_tone, COALESCE(dos, '{}'), COALESCE(donts, '{}'),
			primary_color, secondary_color, logo_url, COALESCE(preferred_terms, '{}'), updated_at
		FROM company_brand WHERE company_id = $1`, companyID).
		Scan(&b.CompanyID, &b.VoiceTone, &b.Dos, &b.Donts,
			&b.PrimaryColor, &b.SecondaryColor, &b.LogoURL, &b.PreferredTerms, &b.UpdatedAt)
	if errors.Is(err, pgx.ErrNoRows) {
		return EmptyBrand(companyID), nil
	}
	if err != nil {
		return BrandKit{}, err
	}
	b.Dos = cleanStrings(b.Dos)
	b.Donts = cleanStrings(b.Donts)
	b.PreferredTerms = cleanStrings(b.PreferredTerms)
	return b, nil
}

// UpsertBrand saves the brand kit for a company.
func UpsertBrand(ctx context.Context, pool *pgxpool.Pool, companyID uuid.UUID, in BrandKit) (BrandKit, error) {
	in.VoiceTone = security.SanitizePrompt(in.VoiceTone, security.MaxBrandFieldRunes)
	in.PrimaryColor = security.TruncateRunes(strings.TrimSpace(in.PrimaryColor), 32)
	in.SecondaryColor = security.TruncateRunes(strings.TrimSpace(in.SecondaryColor), 32)
	logo, err := ValidateLogoURL(in.LogoURL, companyID)
	if err != nil {
		return BrandKit{}, err
	}
	in.LogoURL = logo
	in.Dos = security.SanitizeBrandList(in.Dos)
	in.Donts = security.SanitizeBrandList(in.Donts)
	in.PreferredTerms = security.SanitizeBrandList(in.PreferredTerms)

	var b BrandKit
	err = pool.QueryRow(ctx, `
		INSERT INTO company_brand (
			company_id, voice_tone, dos, donts, primary_color, secondary_color, logo_url, preferred_terms, updated_at
		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8, now())
		ON CONFLICT (company_id) DO UPDATE SET
			voice_tone = EXCLUDED.voice_tone,
			dos = EXCLUDED.dos,
			donts = EXCLUDED.donts,
			primary_color = EXCLUDED.primary_color,
			secondary_color = EXCLUDED.secondary_color,
			logo_url = EXCLUDED.logo_url,
			preferred_terms = EXCLUDED.preferred_terms,
			updated_at = now()
		RETURNING company_id, voice_tone, COALESCE(dos, '{}'), COALESCE(donts, '{}'),
			primary_color, secondary_color, logo_url, COALESCE(preferred_terms, '{}'), updated_at`,
		companyID, in.VoiceTone, in.Dos, in.Donts, in.PrimaryColor, in.SecondaryColor, in.LogoURL, in.PreferredTerms,
	).Scan(&b.CompanyID, &b.VoiceTone, &b.Dos, &b.Donts,
		&b.PrimaryColor, &b.SecondaryColor, &b.LogoURL, &b.PreferredTerms, &b.UpdatedAt)
	if err != nil {
		return BrandKit{}, err
	}
	if b.Dos == nil {
		b.Dos = []string{}
	}
	if b.Donts == nil {
		b.Donts = []string{}
	}
	if b.PreferredTerms == nil {
		b.PreferredTerms = []string{}
	}
	return b, nil
}

// HasContent reports whether any brand guidance is configured.
func (b BrandKit) HasContent() bool {
	return strings.TrimSpace(b.VoiceTone) != "" ||
		len(b.Dos) > 0 ||
		len(b.Donts) > 0 ||
		len(b.PreferredTerms) > 0 ||
		strings.TrimSpace(b.PrimaryColor) != "" ||
		strings.TrimSpace(b.SecondaryColor) != "" ||
		strings.TrimSpace(b.LogoURL) != ""
}

// PromptBlock formats brand voice instructions for AI system prompts.
// Returns empty string when the kit has no usable voice content.
// Kept short (bullet lines) for weak local models / 8k context.
func (b BrandKit) PromptBlock() string {
	var parts []string
	if t := security.SanitizePrompt(b.VoiceTone, 160); t != "" {
		parts = append(parts, "- tone: "+t)
	}
	dos := security.SanitizeBrandList(b.Dos)
	donts := security.SanitizeBrandList(b.Donts)
	terms := security.SanitizeBrandList(b.PreferredTerms)
	if len(dos) > 4 {
		dos = dos[:4]
	}
	if len(donts) > 4 {
		donts = donts[:4]
	}
	if len(terms) > 6 {
		terms = terms[:6]
	}
	if len(dos) > 0 {
		parts = append(parts, "- do: "+strings.Join(dos, "; "))
	}
	if len(donts) > 0 {
		parts = append(parts, "- don't: "+strings.Join(donts, "; "))
	}
	if len(terms) > 0 {
		parts = append(parts, "- terms: "+strings.Join(terms, ", "))
	}
	if len(parts) == 0 {
		return ""
	}
	block := "Brand:\n" + strings.Join(parts, "\n")
	return security.TruncateRunes(block, 500)
}

// FormulaTips returns short brand-aware tips for formula/preview UI.
func (b BrandKit) FormulaTips() []string {
	tips := make([]string, 0, 4)
	if t := strings.TrimSpace(b.VoiceTone); t != "" {
		tips = append(tips, "Match brand tone: "+truncateTip(t, 120))
	}
	if len(b.PreferredTerms) > 0 {
		n := len(b.PreferredTerms)
		if n > 5 {
			n = 5
		}
		tips = append(tips, "Prefer terms: "+strings.Join(b.PreferredTerms[:n], ", "))
	}
	if len(b.Donts) > 0 {
		n := len(b.Donts)
		if n > 3 {
			n = 3
		}
		tips = append(tips, "Avoid: "+strings.Join(b.Donts[:n], "; "))
	}
	if len(b.Dos) > 0 {
		n := len(b.Dos)
		if n > 3 {
			n = 3
		}
		tips = append(tips, "Do: "+strings.Join(b.Dos[:n], "; "))
	}
	return tips
}

func cleanStrings(in []string) []string {
	if len(in) == 0 {
		return []string{}
	}
	out := make([]string, 0, len(in))
	seen := map[string]struct{}{}
	for _, s := range in {
		s = strings.TrimSpace(s)
		if s == "" {
			continue
		}
		key := strings.ToLower(s)
		if _, ok := seen[key]; ok {
			continue
		}
		seen[key] = struct{}{}
		out = append(out, s)
	}
	return out
}

func truncateTip(s string, max int) string {
	s = strings.TrimSpace(s)
	if max <= 0 || len(s) <= max {
		return s
	}
	return strings.TrimSpace(s[:max]) + "…"
}