package store

import (
	"context"
	"fmt"
	"strings"
	"time"

	"github.com/google/uuid"

	ext "git.warky.dev/wdevs/amcs/internal/types"
)

// ──────────────────────────────────────────────
// Helpers
// ──────────────────────────────────────────────

func nilToEmptyStrings(s []string) []string {
	if s == nil {
		return []string{}
	}
	return s
}

// ──────────────────────────────────────────────
// Personas
// ──────────────────────────────────────────────

func (db *DB) CreatePersona(ctx context.Context, p ext.Persona) (ext.Persona, error) {
	if p.Tags == nil {
		p.Tags = []string{}
	}
	row := db.pool.QueryRow(ctx, `
		insert into agent_personas (name, description, summary, detail, tags)
		values ($1, $2, $3, $4, $5)
		returning id, guid, compiled_summary, compiled_detail, compiled_at, created_at, updated_at
	`, p.Name, p.Description, p.Summary, p.Detail, p.Tags)

	created := p
	var id int64
	var guid uuid.UUID
	var cs, cd string
	var compiledAt *time.Time
	var createdAt, updatedAt time.Time
	if err := row.Scan(&id, &guid, &cs, &cd, &compiledAt, &createdAt, &updatedAt); err != nil {
		return ext.Persona{}, fmt.Errorf("create persona: %w", err)
	}
	created.ID = id
	created.GUID = guid
	created.CompiledSummary = cs
	created.CompiledDetail = cd
	created.CompiledAt = compiledAt
	created.CreatedAt = createdAt
	created.UpdatedAt = updatedAt
	return created, nil
}

func (db *DB) UpdatePersona(ctx context.Context, name string, updates map[string]any) (ext.Persona, error) {
	if len(updates) == 0 {
		return db.GetPersonaByName(ctx, name)
	}
	allowed := map[string]bool{"name": true, "description": true, "summary": true, "detail": true, "tags": true}
	setClauses := []string{}
	args := []any{}
	for col, val := range updates {
		if !allowed[col] {
			return ext.Persona{}, fmt.Errorf("unknown field: %s", col)
		}
		args = append(args, val)
		setClauses = append(setClauses, fmt.Sprintf("%s = $%d", col, len(args)))
	}
	args = append(args, name)
	q := fmt.Sprintf(`
		update agent_personas set %s, updated_at = now()
		where name = $%d
		returning id, guid, name, description, summary, detail, compiled_summary, compiled_detail, compiled_at, tags::text[], created_at, updated_at
	`, strings.Join(setClauses, ", "), len(args))

	row := db.pool.QueryRow(ctx, q, args...)
	return scanPersona(row)
}

func (db *DB) DeletePersona(ctx context.Context, name string) error {
	tag, err := db.pool.Exec(ctx, `delete from agent_personas where name = $1`, name)
	if err != nil {
		return fmt.Errorf("delete persona: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("persona not found: %s", name)
	}
	return nil
}

func (db *DB) ListPersonas(ctx context.Context, tag string) ([]ext.Persona, error) {
	q := `select id, guid, name, description, summary, detail, compiled_summary, compiled_detail, compiled_at, tags::text[], created_at, updated_at from agent_personas`
	args := []any{}
	if t := strings.TrimSpace(tag); t != "" {
		args = append(args, t)
		q += fmt.Sprintf(" where $%d = any(tags)", len(args))
	}
	q += " order by name"
	rows, err := db.pool.Query(ctx, q, args...)
	if err != nil {
		return nil, fmt.Errorf("list personas: %w", err)
	}
	defer rows.Close()

	var personas []ext.Persona
	for rows.Next() {
		p, err := scanPersona(rows)
		if err != nil {
			return nil, fmt.Errorf("scan persona: %w", err)
		}
		personas = append(personas, p)
	}
	return personas, rows.Err()
}

func (db *DB) GetPersonaByName(ctx context.Context, name string) (ext.Persona, error) {
	row := db.pool.QueryRow(ctx, `
		select id, guid, name, description, summary, detail, compiled_summary, compiled_detail, compiled_at, tags::text[], created_at, updated_at
		from agent_personas where name = $1
	`, name)
	p, err := scanPersona(row)
	if err != nil {
		return ext.Persona{}, fmt.Errorf("get persona: %w", err)
	}
	return p, nil
}

// GetPersona assembles the full persona with parts, skills, guardrails, traits,
// and arc state. Assembly priority per part_type: overrides > arc stage > persona base.
func (db *DB) GetPersona(ctx context.Context, name string, detail bool, overrides map[string]string) (ext.PersonaFull, error) {
	// 1. Persona metadata
	persona, err := db.GetPersonaByName(ctx, name)
	if err != nil {
		return ext.PersonaFull{}, err
	}

	// 2. Base persona parts (ordered)
	baseParts, err := db.listPersonaParts(ctx, persona.ID)
	if err != nil {
		return ext.PersonaFull{}, err
	}

	// 3. Arc state + stage parts
	arcState, stageParts, err := db.getArcStateAndParts(ctx, persona.ID)
	if err != nil {
		return ext.PersonaFull{}, err
	}

	// 4. Assemble: start with base, override with arc stage parts per type
	assembled := assembleParts(baseParts, stageParts, "arc_stage")

	// 5. Apply runtime overrides (fetch by name, replace per type)
	if len(overrides) > 0 {
		overrideParts, err := db.fetchPartsByNames(ctx, overrideValues(overrides))
		if err != nil {
			return ext.PersonaFull{}, err
		}
		// Build name→part lookup
		byName := make(map[string]rawPart, len(overrideParts))
		for _, p := range overrideParts {
			byName[p.Name] = p
		}
		for partType, partName := range overrides {
			op, ok := byName[partName]
			if !ok {
				return ext.PersonaFull{}, fmt.Errorf("override part not found: %s", partName)
			}
			if op.PartType != partType {
				return ext.PersonaFull{}, fmt.Errorf("override part %q has type %q, expected %q", partName, op.PartType, partType)
			}
			// Remove all parts of this type, then append the override
			without := assembled[:0]
			for _, ap := range assembled {
				if ap.PartType != partType {
					without = append(without, ap)
				}
			}
			op.Source = "override"
			assembled = append(without, op)
		}
	}

	// 6. Skills, guardrails, traits
	skills, err := db.listPersonaSkills(ctx, persona.ID)
	if err != nil {
		return ext.PersonaFull{}, err
	}
	guardrails, err := db.listPersonaGuardrails(ctx, persona.ID)
	if err != nil {
		return ext.PersonaFull{}, err
	}
	traits, err := db.listPersonaTraits(ctx, persona.ID)
	if err != nil {
		return ext.PersonaFull{}, err
	}

	// 7. Build output
	body := persona.Summary
	if detail && persona.Detail != "" {
		body = persona.Detail
	}

	out := ext.PersonaFull{
		Name:            persona.Name,
		Description:     persona.Description,
		Body:            body,
		CompiledSummary: persona.CompiledSummary,
		Tags:            persona.Tags,
		Arc:             arcState,
		Detail:          detail,
	}

	for _, rp := range assembled {
		partBody := rp.Summary
		if detail && rp.Content != "" {
			partBody = rp.Content
		}
		out.Parts = append(out.Parts, ext.AssembledPart{
			Name:        rp.Name,
			PartType:    rp.PartType,
			Description: rp.Description,
			Body:        partBody,
			Tags:        rp.Tags,
			Source:      rp.Source,
		})
	}

	for _, s := range skills {
		entry := ext.PersonaSkillEntry{
			ID:          s.ID,
			Name:        s.Name,
			Description: s.Description,
			Tags:        s.Tags,
		}
		if detail {
			entry.Content = s.Content
		}
		out.Skills = append(out.Skills, entry)
	}

	for _, g := range guardrails {
		entry := ext.PersonaGuardrailEntry{
			ID:          g.ID,
			Name:        g.Name,
			Description: g.Description,
			Tags:        g.Tags,
		}
		if detail {
			entry.Content = g.Content
			entry.Severity = g.Severity
		}
		out.Guardrails = append(out.Guardrails, entry)
	}

	for _, t := range traits {
		entry := ext.PersonaTraitEntry{
			ID:          t.ID,
			Name:        t.Name,
			TraitType:   t.TraitType,
			Description: t.Description,
			Tags:        t.Tags,
		}
		if detail {
			entry.Instruction = t.Instruction
		}
		out.Traits = append(out.Traits, entry)
	}

	if out.Parts == nil {
		out.Parts = []ext.AssembledPart{}
	}
	if out.Skills == nil {
		out.Skills = []ext.PersonaSkillEntry{}
	}
	if out.Guardrails == nil {
		out.Guardrails = []ext.PersonaGuardrailEntry{}
	}
	if out.Traits == nil {
		out.Traits = []ext.PersonaTraitEntry{}
	}

	return out, nil
}

// GetPersonaManifest returns a lightweight structure-only view of the persona.
func (db *DB) GetPersonaManifest(ctx context.Context, name string) (ext.PersonaManifest, error) {
	persona, err := db.GetPersonaByName(ctx, name)
	if err != nil {
		return ext.PersonaManifest{}, err
	}

	baseParts, err := db.listPersonaParts(ctx, persona.ID)
	if err != nil {
		return ext.PersonaManifest{}, err
	}
	arcState, stageParts, err := db.getArcStateAndParts(ctx, persona.ID)
	if err != nil {
		return ext.PersonaManifest{}, err
	}
	assembled := assembleParts(baseParts, stageParts, "arc_stage")

	skills, err := db.listPersonaSkills(ctx, persona.ID)
	if err != nil {
		return ext.PersonaManifest{}, err
	}
	guardrails, err := db.listPersonaGuardrails(ctx, persona.ID)
	if err != nil {
		return ext.PersonaManifest{}, err
	}
	traits, err := db.listPersonaTraits(ctx, persona.ID)
	if err != nil {
		return ext.PersonaManifest{}, err
	}

	manifest := ext.PersonaManifest{
		Name:        persona.Name,
		Description: persona.Description,
		Arc:         arcState,
		OnDemandTools: []string{
			"get_agent_part(name)      — load full content of a specific part",
			"get_agent_trait(name)     — load instruction for a specific trait",
			"get_skill(name)           — load skill content",
			"get_guardrail(name)       — load guardrail content",
			"compile_persona(name)     — load pre-merged compiled_summary if full context needed",
			"get_agent_persona(name, detail=true) — load full persona with all content",
		},
	}

	for _, rp := range assembled {
		manifest.Parts = append(manifest.Parts, ext.ManifestPart{
			Name:        rp.Name,
			PartType:    rp.PartType,
			Description: rp.Description,
		})
	}
	for _, s := range skills {
		manifest.Skills = append(manifest.Skills, ext.ManifestSkill{
			ID:          s.ID,
			Name:        s.Name,
			Description: s.Description,
		})
	}
	for _, g := range guardrails {
		manifest.Guardrails = append(manifest.Guardrails, ext.ManifestGuardrail{
			ID:          g.ID,
			Name:        g.Name,
			Description: g.Description,
			Severity:    g.Severity,
		})
	}
	for _, t := range traits {
		manifest.Traits = append(manifest.Traits, ext.ManifestTrait{
			Name:        t.Name,
			TraitType:   t.TraitType,
			Description: t.Description,
		})
	}

	if manifest.Parts == nil {
		manifest.Parts = []ext.ManifestPart{}
	}
	if manifest.Skills == nil {
		manifest.Skills = []ext.ManifestSkill{}
	}
	if manifest.Guardrails == nil {
		manifest.Guardrails = []ext.ManifestGuardrail{}
	}
	if manifest.Traits == nil {
		manifest.Traits = []ext.ManifestTrait{}
	}

	return manifest, nil
}

// CompilePersona regenerates compiled_summary and compiled_detail from current parts and arc stage.
func (db *DB) CompilePersona(ctx context.Context, name string) (ext.Persona, error) {
	persona, err := db.GetPersonaByName(ctx, name)
	if err != nil {
		return ext.Persona{}, err
	}

	baseParts, err := db.listPersonaParts(ctx, persona.ID)
	if err != nil {
		return ext.Persona{}, err
	}
	_, stageParts, err := db.getArcStateAndParts(ctx, persona.ID)
	if err != nil {
		return ext.Persona{}, err
	}
	assembled := assembleParts(baseParts, stageParts, "arc_stage")

	summaryParts := []string{persona.Summary}
	detailParts := []string{persona.Detail}
	for _, rp := range assembled {
		if rp.Summary != "" {
			summaryParts = append(summaryParts, rp.Summary)
		}
		if rp.Content != "" {
			detailParts = append(detailParts, rp.Content)
		}
	}

	compiledSummary := strings.Join(summaryParts, "\n\n")
	compiledDetail := strings.Join(detailParts, "\n\n")

	row := db.pool.QueryRow(ctx, `
		update agent_personas
		set compiled_summary = $1, compiled_detail = $2, compiled_at = now(), updated_at = now()
		where id = $3
		returning id, guid, name, description, summary, detail, compiled_summary, compiled_detail, compiled_at, tags::text[], created_at, updated_at
	`, compiledSummary, compiledDetail, persona.ID)
	return scanPersona(row)
}

// ──────────────────────────────────────────────
// Parts
// ──────────────────────────────────────────────

func (db *DB) CreatePart(ctx context.Context, p ext.Part) (ext.Part, error) {
	if p.Tags == nil {
		p.Tags = []string{}
	}
	row := db.pool.QueryRow(ctx, `
		insert into agent_parts (name, part_type, description, summary, content, tags)
		values ($1, $2, $3, $4, $5, $6)
		returning id, guid, created_at, updated_at
	`, p.Name, p.PartType, p.Description, p.Summary, p.Content, p.Tags)

	created := p
	var id int64
	var guid uuid.UUID
	var createdAt, updatedAt time.Time
	if err := row.Scan(&id, &guid, &createdAt, &updatedAt); err != nil {
		return ext.Part{}, fmt.Errorf("create part: %w", err)
	}
	created.ID = id
	created.GUID = guid
	created.CreatedAt = createdAt
	created.UpdatedAt = updatedAt
	return created, nil
}

func (db *DB) UpdatePart(ctx context.Context, name string, updates map[string]any) (ext.Part, error) {
	if len(updates) == 0 {
		return db.GetPartByName(ctx, name)
	}
	allowed := map[string]bool{"name": true, "part_type": true, "description": true, "summary": true, "content": true, "tags": true}
	setClauses := []string{}
	args := []any{}
	for col, val := range updates {
		if !allowed[col] {
			return ext.Part{}, fmt.Errorf("unknown field: %s", col)
		}
		args = append(args, val)
		setClauses = append(setClauses, fmt.Sprintf("%s = $%d", col, len(args)))
	}
	args = append(args, name)
	q := fmt.Sprintf(`
		update agent_parts set %s, updated_at = now()
		where name = $%d
		returning id, guid, name, part_type, description, summary, content, tags::text[], created_at, updated_at
	`, strings.Join(setClauses, ", "), len(args))

	row := db.pool.QueryRow(ctx, q, args...)
	return scanPart(row)
}

func (db *DB) DeletePart(ctx context.Context, name string) error {
	tag, err := db.pool.Exec(ctx, `delete from agent_parts where name = $1`, name)
	if err != nil {
		return fmt.Errorf("delete part: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("part not found: %s", name)
	}
	return nil
}

func (db *DB) ListParts(ctx context.Context, partType, tag string) ([]ext.Part, error) {
	args := []any{}
	conditions := []string{}
	if t := strings.TrimSpace(partType); t != "" {
		args = append(args, t)
		conditions = append(conditions, fmt.Sprintf("part_type = $%d", len(args)))
	}
	if t := strings.TrimSpace(tag); t != "" {
		args = append(args, t)
		conditions = append(conditions, fmt.Sprintf("$%d = any(tags)", len(args)))
	}
	q := `select id, guid, name, part_type, description, summary, content, tags::text[], created_at, updated_at from agent_parts`
	if len(conditions) > 0 {
		q += " where " + strings.Join(conditions, " and ")
	}
	q += " order by part_type, name"
	rows, err := db.pool.Query(ctx, q, args...)
	if err != nil {
		return nil, fmt.Errorf("list parts: %w", err)
	}
	defer rows.Close()

	var parts []ext.Part
	for rows.Next() {
		p, err := scanPart(rows)
		if err != nil {
			return nil, fmt.Errorf("scan part: %w", err)
		}
		parts = append(parts, p)
	}
	return parts, rows.Err()
}

func (db *DB) GetPartByName(ctx context.Context, name string) (ext.Part, error) {
	row := db.pool.QueryRow(ctx, `
		select id, guid, name, part_type, description, summary, content, tags::text[], created_at, updated_at
		from agent_parts where name = $1
	`, name)
	p, err := scanPart(row)
	if err != nil {
		return ext.Part{}, fmt.Errorf("get part: %w", err)
	}
	return p, nil
}

// ──────────────────────────────────────────────
// Persona-Part links
// ──────────────────────────────────────────────

func (db *DB) AddPersonaPart(ctx context.Context, personaName, partName string, order, priority int) error {
	persona, err := db.GetPersonaByName(ctx, personaName)
	if err != nil {
		return err
	}
	part, err := db.GetPartByName(ctx, partName)
	if err != nil {
		return err
	}
	_, err = db.pool.Exec(ctx, `
		insert into agent_persona_parts (persona_id, part_id, part_order, priority)
		values ($1, $2, $3, $4)
		on conflict (persona_id, part_id) do update set part_order = excluded.part_order, priority = excluded.priority
	`, persona.ID, part.ID, order, priority)
	if err != nil {
		return fmt.Errorf("add persona part: %w", err)
	}
	return nil
}

func (db *DB) RemovePersonaPart(ctx context.Context, personaName, partName string) error {
	tag, err := db.pool.Exec(ctx, `
		delete from agent_persona_parts
		where persona_id = (select id from agent_personas where name = $1)
		  and part_id    = (select id from agent_parts      where name = $2)
	`, personaName, partName)
	if err != nil {
		return fmt.Errorf("remove persona part: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("persona-part link not found")
	}
	return nil
}

// ──────────────────────────────────────────────
// Persona-Skill links
// ──────────────────────────────────────────────

func (db *DB) AddPersonaSkill(ctx context.Context, personaID, skillID int64) error {
	_, err := db.pool.Exec(ctx, `
		insert into agent_persona_skills (persona_id, skill_id)
		values ($1, $2) on conflict do nothing
	`, personaID, skillID)
	if err != nil {
		return fmt.Errorf("add persona skill: %w", err)
	}
	return nil
}

func (db *DB) RemovePersonaSkill(ctx context.Context, personaID, skillID int64) error {
	tag, err := db.pool.Exec(ctx, `
		delete from agent_persona_skills where persona_id = $1 and skill_id = $2
	`, personaID, skillID)
	if err != nil {
		return fmt.Errorf("remove persona skill: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("persona-skill link not found")
	}
	return nil
}

// ──────────────────────────────────────────────
// Persona-Guardrail links
// ──────────────────────────────────────────────

func (db *DB) AddPersonaGuardrail(ctx context.Context, personaID, guardrailID int64) error {
	_, err := db.pool.Exec(ctx, `
		insert into agent_persona_guardrails (persona_id, guardrail_id)
		values ($1, $2) on conflict do nothing
	`, personaID, guardrailID)
	if err != nil {
		return fmt.Errorf("add persona guardrail: %w", err)
	}
	return nil
}

func (db *DB) RemovePersonaGuardrail(ctx context.Context, personaID, guardrailID int64) error {
	tag, err := db.pool.Exec(ctx, `
		delete from agent_persona_guardrails where persona_id = $1 and guardrail_id = $2
	`, personaID, guardrailID)
	if err != nil {
		return fmt.Errorf("remove persona guardrail: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("persona-guardrail link not found")
	}
	return nil
}

// ──────────────────────────────────────────────
// Traits
// ──────────────────────────────────────────────

func (db *DB) CreateTrait(ctx context.Context, t ext.Trait) (ext.Trait, error) {
	if t.Tags == nil {
		t.Tags = []string{}
	}
	row := db.pool.QueryRow(ctx, `
		insert into agent_traits (name, trait_type, description, instruction, tags)
		values ($1, $2, $3, $4, $5)
		returning id, guid, created_at, updated_at
	`, t.Name, t.TraitType, t.Description, t.Instruction, t.Tags)

	created := t
	var id int64
	var guid uuid.UUID
	var createdAt, updatedAt time.Time
	if err := row.Scan(&id, &guid, &createdAt, &updatedAt); err != nil {
		return ext.Trait{}, fmt.Errorf("create trait: %w", err)
	}
	created.ID = id
	created.GUID = guid
	created.CreatedAt = createdAt
	created.UpdatedAt = updatedAt
	return created, nil
}

func (db *DB) UpdateTrait(ctx context.Context, name string, updates map[string]any) (ext.Trait, error) {
	if len(updates) == 0 {
		return db.GetTraitByName(ctx, name)
	}
	allowed := map[string]bool{"name": true, "trait_type": true, "description": true, "instruction": true, "tags": true}
	setClauses := []string{}
	args := []any{}
	for col, val := range updates {
		if !allowed[col] {
			return ext.Trait{}, fmt.Errorf("unknown field: %s", col)
		}
		args = append(args, val)
		setClauses = append(setClauses, fmt.Sprintf("%s = $%d", col, len(args)))
	}
	args = append(args, name)
	q := fmt.Sprintf(`
		update agent_traits set %s, updated_at = now()
		where name = $%d
		returning id, guid, name, trait_type, description, instruction, tags::text[], created_at, updated_at
	`, strings.Join(setClauses, ", "), len(args))

	row := db.pool.QueryRow(ctx, q, args...)
	return scanTrait(row)
}

func (db *DB) DeleteTrait(ctx context.Context, name string) error {
	tag, err := db.pool.Exec(ctx, `delete from agent_traits where name = $1`, name)
	if err != nil {
		return fmt.Errorf("delete trait: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("trait not found: %s", name)
	}
	return nil
}

func (db *DB) ListTraits(ctx context.Context, traitType, tag string) ([]ext.Trait, error) {
	args := []any{}
	conditions := []string{}
	if t := strings.TrimSpace(traitType); t != "" {
		args = append(args, t)
		conditions = append(conditions, fmt.Sprintf("trait_type = $%d", len(args)))
	}
	if t := strings.TrimSpace(tag); t != "" {
		args = append(args, t)
		conditions = append(conditions, fmt.Sprintf("$%d = any(tags)", len(args)))
	}
	q := `select id, guid, name, trait_type, description, instruction, tags::text[], created_at, updated_at from agent_traits`
	if len(conditions) > 0 {
		q += " where " + strings.Join(conditions, " and ")
	}
	q += " order by trait_type, name"
	rows, err := db.pool.Query(ctx, q, args...)
	if err != nil {
		return nil, fmt.Errorf("list traits: %w", err)
	}
	defer rows.Close()

	var traits []ext.Trait
	for rows.Next() {
		t, err := scanTrait(rows)
		if err != nil {
			return nil, fmt.Errorf("scan trait: %w", err)
		}
		traits = append(traits, t)
	}
	return traits, rows.Err()
}

func (db *DB) GetTraitByName(ctx context.Context, name string) (ext.Trait, error) {
	row := db.pool.QueryRow(ctx, `
		select id, guid, name, trait_type, description, instruction, tags::text[], created_at, updated_at
		from agent_traits where name = $1
	`, name)
	t, err := scanTrait(row)
	if err != nil {
		return ext.Trait{}, fmt.Errorf("get trait: %w", err)
	}
	return t, nil
}

func (db *DB) AddPersonaTrait(ctx context.Context, personaID, traitID int64) error {
	_, err := db.pool.Exec(ctx, `
		insert into agent_persona_traits (persona_id, trait_id)
		values ($1, $2) on conflict do nothing
	`, personaID, traitID)
	if err != nil {
		return fmt.Errorf("add persona trait: %w", err)
	}
	return nil
}

func (db *DB) RemovePersonaTrait(ctx context.Context, personaID, traitID int64) error {
	tag, err := db.pool.Exec(ctx, `
		delete from agent_persona_traits where persona_id = $1 and trait_id = $2
	`, personaID, traitID)
	if err != nil {
		return fmt.Errorf("remove persona trait: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("persona-trait link not found")
	}
	return nil
}

// ──────────────────────────────────────────────
// Character Arcs
// ──────────────────────────────────────────────

func (db *DB) CreateCharacterArc(ctx context.Context, arc ext.CharacterArc) (ext.CharacterArc, error) {
	row := db.pool.QueryRow(ctx, `
		insert into character_arcs (name, description, summary)
		values ($1, $2, $3)
		returning id, created_at, updated_at
	`, arc.Name, arc.Description, arc.Summary)

	created := arc
	var id int64
	var createdAt, updatedAt time.Time
	if err := row.Scan(&id, &createdAt, &updatedAt); err != nil {
		return ext.CharacterArc{}, fmt.Errorf("create character arc: %w", err)
	}
	created.ID = id
	created.CreatedAt = createdAt
	created.UpdatedAt = updatedAt
	return created, nil
}

func (db *DB) ListCharacterArcs(ctx context.Context) ([]ext.CharacterArc, error) {
	rows, err := db.pool.Query(ctx, `
		select id, name, description, summary, created_at, updated_at
		from character_arcs order by name
	`)
	if err != nil {
		return nil, fmt.Errorf("list character arcs: %w", err)
	}
	defer rows.Close()

	var arcs []ext.CharacterArc
	for rows.Next() {
		var a ext.CharacterArc
		if err := rows.Scan(&a.ID, &a.Name, &a.Description, &a.Summary, &a.CreatedAt, &a.UpdatedAt); err != nil {
			return nil, fmt.Errorf("scan character arc: %w", err)
		}
		arcs = append(arcs, a)
	}
	return arcs, rows.Err()
}

func (db *DB) AddArcStage(ctx context.Context, arcName string, stage ext.ArcStage) (ext.ArcStage, error) {
	row := db.pool.QueryRow(ctx, `
		insert into arc_stages (arc_id, name, stage_order, description, condition)
		values ((select id from character_arcs where name = $1), $2, $3, $4, $5)
		returning id, arc_id, created_at
	`, arcName, stage.Name, stage.StageOrder, stage.Description, stage.Condition)

	created := stage
	if err := row.Scan(&created.ID, &created.ArcID, &created.CreatedAt); err != nil {
		return ext.ArcStage{}, fmt.Errorf("add arc stage: %w", err)
	}
	return created, nil
}

func (db *DB) AddStagePart(ctx context.Context, stageID int64, partName string) error {
	_, err := db.pool.Exec(ctx, `
		insert into arc_stage_parts (stage_id, part_id)
		values ($1, (select id from agent_parts where name = $2))
		on conflict do nothing
	`, stageID, partName)
	if err != nil {
		return fmt.Errorf("add stage part: %w", err)
	}
	return nil
}

func (db *DB) RemoveStagePart(ctx context.Context, stageID int64, partName string) error {
	tag, err := db.pool.Exec(ctx, `
		delete from arc_stage_parts
		where stage_id = $1 and part_id = (select id from agent_parts where name = $2)
	`, stageID, partName)
	if err != nil {
		return fmt.Errorf("remove stage part: %w", err)
	}
	if tag.RowsAffected() == 0 {
		return fmt.Errorf("stage-part link not found")
	}
	return nil
}

func (db *DB) AssignPersonaArc(ctx context.Context, personaName, arcName, startStageName string) error {
	_, err := db.pool.Exec(ctx, `
		insert into persona_arc (persona_id, arc_id, current_stage_id)
		values (
			(select id from agent_personas where name = $1),
			(select id from character_arcs   where name = $2),
			(select id from arc_stages       where arc_id = (select id from character_arcs where name = $2) and name = $3)
		)
		on conflict (persona_id) do update
		  set arc_id = excluded.arc_id,
		      current_stage_id = excluded.current_stage_id,
		      updated_at = now()
	`, personaName, arcName, startStageName)
	if err != nil {
		return fmt.Errorf("assign persona arc: %w", err)
	}
	return nil
}

func (db *DB) AdvancePersonaStage(ctx context.Context, personaName string) (ext.ArcStage, error) {
	row := db.pool.QueryRow(ctx, `
		with current as (
			select pa.persona_id, pa.arc_id, pa.current_stage_id, s.stage_order
			from persona_arc pa
			join arc_stages s on s.id = pa.current_stage_id
			where pa.persona_id = (select id from agent_personas where name = $1)
		),
		next_stage as (
			select s.id, s.arc_id, s.name, s.stage_order, s.description, s.condition, s.created_at
			from arc_stages s
			join current c on c.arc_id = s.arc_id
			where s.stage_order > c.stage_order
			order by s.stage_order
			limit 1
		)
		update persona_arc pa
		set current_stage_id = next_stage.id, updated_at = now()
		from next_stage, current
		where pa.persona_id = current.persona_id
		returning next_stage.id, next_stage.arc_id, next_stage.name, next_stage.stage_order, next_stage.description, next_stage.condition, next_stage.created_at
	`, personaName)

	var s ext.ArcStage
	if err := row.Scan(&s.ID, &s.ArcID, &s.Name, &s.StageOrder, &s.Description, &s.Condition, &s.CreatedAt); err != nil {
		return ext.ArcStage{}, fmt.Errorf("advance persona stage: %w", err)
	}
	return s, nil
}

func (db *DB) ResetPersonaStage(ctx context.Context, personaName string) (ext.ArcStage, error) {
	row := db.pool.QueryRow(ctx, `
		with first_stage as (
			select s.id, s.arc_id, s.name, s.stage_order, s.description, s.condition, s.created_at
			from arc_stages s
			join persona_arc pa on pa.arc_id = s.arc_id
			where pa.persona_id = (select id from agent_personas where name = $1)
			order by s.stage_order
			limit 1
		)
		update persona_arc pa
		set current_stage_id = first_stage.id, updated_at = now()
		from first_stage
		where pa.persona_id = (select id from agent_personas where name = $1)
		returning first_stage.id, first_stage.arc_id, first_stage.name, first_stage.stage_order, first_stage.description, first_stage.condition, first_stage.created_at
	`, personaName)

	var s ext.ArcStage
	if err := row.Scan(&s.ID, &s.ArcID, &s.Name, &s.StageOrder, &s.Description, &s.Condition, &s.CreatedAt); err != nil {
		return ext.ArcStage{}, fmt.Errorf("reset persona stage: %w", err)
	}
	return s, nil
}

// ──────────────────────────────────────────────
// Internal helpers
// ──────────────────────────────────────────────

type rawPart struct {
	ID          int64
	Name        string
	PartType    string
	Description string
	Summary     string
	Content     string
	Tags        []string
	Order       int
	Priority    int
	Source      string
}

func (db *DB) listPersonaParts(ctx context.Context, personaID int64) ([]rawPart, error) {
	rows, err := db.pool.Query(ctx, `
		select ap.id, ap.name, ap.part_type, ap.description, ap.summary, ap.content, ap.tags::text[],
		       app.part_order, app.priority
		from agent_parts ap
		join agent_persona_parts app on app.part_id = ap.id
		where app.persona_id = $1
		order by app.part_order, ap.part_type, ap.name
	`, personaID)
	if err != nil {
		return nil, fmt.Errorf("list persona parts: %w", err)
	}
	defer rows.Close()

	var parts []rawPart
	for rows.Next() {
		var rp rawPart
		var tags []string
		if err := rows.Scan(&rp.ID, &rp.Name, &rp.PartType, &rp.Description, &rp.Summary, &rp.Content, &tags, &rp.Order, &rp.Priority); err != nil {
			return nil, fmt.Errorf("scan persona part: %w", err)
		}
		rp.Tags = nilToEmptyStrings(tags)
		rp.Source = "persona"
		parts = append(parts, rp)
	}
	return parts, rows.Err()
}

func (db *DB) getArcStateAndParts(ctx context.Context, personaID int64) (*ext.PersonaArcState, []rawPart, error) {
	row := db.pool.QueryRow(ctx, `
		select ca.name, s.id, s.name, s.stage_order, s.description, s.condition
		from persona_arc pa
		join character_arcs ca on ca.id = pa.arc_id
		join arc_stages s on s.id = pa.current_stage_id
		where pa.persona_id = $1
	`, personaID)

	var arcName, stageName, stageDesc, stageCond string
	var stageID int64
	var stageOrder int
	if err := row.Scan(&arcName, &stageID, &stageName, &stageOrder, &stageDesc, &stageCond); err != nil {
		// No arc assigned — not an error
		return nil, nil, nil
	}

	arcState := &ext.PersonaArcState{
		ArcName:     arcName,
		StageName:   stageName,
		StageOrder:  stageOrder,
		Description: stageDesc,
		Condition:   stageCond,
	}

	rows, err := db.pool.Query(ctx, `
		select ap.id, ap.name, ap.part_type, ap.description, ap.summary, ap.content, ap.tags::text[]
		from agent_parts ap
		join arc_stage_parts asp on asp.part_id = ap.id
		where asp.stage_id = $1
		order by ap.part_type, ap.name
	`, stageID)
	if err != nil {
		return nil, nil, fmt.Errorf("list stage parts: %w", err)
	}
	defer rows.Close()

	var parts []rawPart
	for rows.Next() {
		var rp rawPart
		var tags []string
		if err := rows.Scan(&rp.ID, &rp.Name, &rp.PartType, &rp.Description, &rp.Summary, &rp.Content, &tags); err != nil {
			return nil, nil, fmt.Errorf("scan stage part: %w", err)
		}
		rp.Tags = nilToEmptyStrings(tags)
		rp.Source = "arc_stage"
		parts = append(parts, rp)
	}
	return arcState, parts, rows.Err()
}

// assembleParts merges base parts with override parts. Override parts replace all
// base parts of the same part_type.
func assembleParts(base, overrides []rawPart, overrideSource string) []rawPart {
	if len(overrides) == 0 {
		return append([]rawPart{}, base...)
	}

	overrideTypes := make(map[string]bool)
	for _, op := range overrides {
		overrideTypes[op.PartType] = true
	}

	result := make([]rawPart, 0, len(base)+len(overrides))
	for _, bp := range base {
		if !overrideTypes[bp.PartType] {
			result = append(result, bp)
		}
	}
	for _, op := range overrides {
		op.Source = overrideSource
		result = append(result, op)
	}
	return result
}

func (db *DB) fetchPartsByNames(ctx context.Context, names []string) ([]rawPart, error) {
	if len(names) == 0 {
		return nil, nil
	}
	rows, err := db.pool.Query(ctx, `
		select id, name, part_type, description, summary, content, tags::text[]
		from agent_parts where name = any($1)
	`, names)
	if err != nil {
		return nil, fmt.Errorf("fetch parts by names: %w", err)
	}
	defer rows.Close()

	var parts []rawPart
	for rows.Next() {
		var rp rawPart
		var tags []string
		if err := rows.Scan(&rp.ID, &rp.Name, &rp.PartType, &rp.Description, &rp.Summary, &rp.Content, &tags); err != nil {
			return nil, fmt.Errorf("scan part by name: %w", err)
		}
		rp.Tags = nilToEmptyStrings(tags)
		parts = append(parts, rp)
	}
	return parts, rows.Err()
}

func (db *DB) listPersonaSkills(ctx context.Context, personaID int64) ([]AgentSkillRow, error) {
	rows, err := db.pool.Query(ctx, `
		select s.id, s.name, s.description, s.content, s.tags::text[]
		from agent_skills s
		join agent_persona_skills aps on aps.skill_id = s.id
		where aps.persona_id = $1
		order by s.name
	`, personaID)
	if err != nil {
		return nil, fmt.Errorf("list persona skills: %w", err)
	}
	defer rows.Close()

	var skills []AgentSkillRow
	for rows.Next() {
		var s AgentSkillRow
		var tags []string
		if err := rows.Scan(&s.ID, &s.Name, &s.Description, &s.Content, &tags); err != nil {
			return nil, fmt.Errorf("scan persona skill: %w", err)
		}
		s.Tags = nilToEmptyStrings(tags)
		skills = append(skills, s)
	}
	return skills, rows.Err()
}

func (db *DB) listPersonaGuardrails(ctx context.Context, personaID int64) ([]AgentGuardrailRow, error) {
	rows, err := db.pool.Query(ctx, `
		select g.id, g.name, g.description, g.content, g.severity, g.tags::text[]
		from agent_guardrails g
		join agent_persona_guardrails apg on apg.guardrail_id = g.id
		where apg.persona_id = $1
		order by g.name
	`, personaID)
	if err != nil {
		return nil, fmt.Errorf("list persona guardrails: %w", err)
	}
	defer rows.Close()

	var gs []AgentGuardrailRow
	for rows.Next() {
		var g AgentGuardrailRow
		var tags []string
		if err := rows.Scan(&g.ID, &g.Name, &g.Description, &g.Content, &g.Severity, &tags); err != nil {
			return nil, fmt.Errorf("scan persona guardrail: %w", err)
		}
		g.Tags = nilToEmptyStrings(tags)
		gs = append(gs, g)
	}
	return gs, rows.Err()
}

func (db *DB) listPersonaTraits(ctx context.Context, personaID int64) ([]ext.Trait, error) {
	rows, err := db.pool.Query(ctx, `
		select t.id, t.guid, t.name, t.trait_type, t.description, t.instruction, t.tags::text[], t.created_at, t.updated_at
		from agent_traits t
		join agent_persona_traits apt on apt.trait_id = t.id
		where apt.persona_id = $1
		order by t.trait_type, t.name
	`, personaID)
	if err != nil {
		return nil, fmt.Errorf("list persona traits: %w", err)
	}
	defer rows.Close()

	var traits []ext.Trait
	for rows.Next() {
		t, err := scanTrait(rows)
		if err != nil {
			return nil, fmt.Errorf("scan persona trait: %w", err)
		}
		traits = append(traits, t)
	}
	return traits, rows.Err()
}

// Minimal row types used internally (avoid importing full ext types for joins)
type AgentSkillRow struct {
	ID          int64
	Name        string
	Description string
	Content     string
	Tags        []string
}

type AgentGuardrailRow struct {
	ID          int64
	Name        string
	Description string
	Content     string
	Severity    string
	Tags        []string
}

func overrideValues(m map[string]string) []string {
	out := make([]string, 0, len(m))
	for _, v := range m {
		out = append(out, v)
	}
	return out
}

// ──────────────────────────────────────────────
// Scanners
// ──────────────────────────────────────────────

type personaScanner interface{ Scan(dest ...any) error }
type partScanner interface{ Scan(dest ...any) error }
type traitScanner interface{ Scan(dest ...any) error }

func scanPersona(row personaScanner) (ext.Persona, error) {
	var p ext.Persona
	var tags []string
	if err := row.Scan(&p.ID, &p.GUID, &p.Name, &p.Description, &p.Summary, &p.Detail,
		&p.CompiledSummary, &p.CompiledDetail, &p.CompiledAt, &tags, &p.CreatedAt, &p.UpdatedAt); err != nil {
		return ext.Persona{}, err
	}
	p.Tags = nilToEmptyStrings(tags)
	return p, nil
}

func scanPart(row partScanner) (ext.Part, error) {
	var p ext.Part
	var tags []string
	if err := row.Scan(&p.ID, &p.GUID, &p.Name, &p.PartType, &p.Description, &p.Summary, &p.Content, &tags, &p.CreatedAt, &p.UpdatedAt); err != nil {
		return ext.Part{}, err
	}
	p.Tags = nilToEmptyStrings(tags)
	return p, nil
}

func scanTrait(row traitScanner) (ext.Trait, error) {
	var t ext.Trait
	var tags []string
	if err := row.Scan(&t.ID, &t.GUID, &t.Name, &t.TraitType, &t.Description, &t.Instruction, &tags, &t.CreatedAt, &t.UpdatedAt); err != nil {
		return ext.Trait{}, err
	}
	t.Tags = nilToEmptyStrings(tags)
	return t, nil
}