package httpapi

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"

	"github.com/dtoro/oikos/internal/db/sqlcgen"
	"github.com/dtoro/oikos/internal/domain"
	"github.com/dtoro/oikos/internal/httpapi/gen"
	"github.com/dtoro/oikos/internal/observability"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

// ─── Skills ────────────────────────────────────────────────────────────

func (s *Server) ListSkills(ctx context.Context, req gen.ListSkillsRequestObject) (gen.ListSkillsResponseObject, error) {
	limit := clampLimit(req.Params.Limit)
	rows, err := s.pool.Query(ctx, `
		SELECT s.entity_id, s.version, s.name, s.procedure, s.applies_type,
		       s.action, s.pattern_ids, s.status, s.success_rate,
		       s.changed_by::text, s.change_reason, s.last_used_at
		FROM skills s
		WHERE ($1::text IS NULL OR s.status = $1)
		  AND ($2::text IS NULL OR s.applies_type = $2)
		  AND ($3::text IS NULL OR s.action = $3)
		ORDER BY s.name, s.version DESC`,
		req.Params.Status, req.Params.AppliesTo, req.Params.Action)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	// Deduplicate to latest version per skill (the ORDER BY name, version DESC
	// means the first row per name is the latest).
	seen := map[string]bool{}
	items := []gen.Skill{}
	for rows.Next() {
		var s gen.Skill
		var procBytes []byte
		var patternIDs []uuid.UUID
		if err := rows.Scan(&s.Id, &s.Version, &s.Name, &procBytes, &s.AppliesType,
			&s.Action, &patternIDs, &s.Status, &s.SuccessRate,
			&s.ChangedBy, &s.ChangeReason, &s.LastUsedAt); err != nil {
			return nil, err
		}
		if seen[s.Id.String()] {
			continue
		}
		seen[s.Id.String()] = true
		if err := json.Unmarshal(procBytes, &s.Procedure); err != nil {
			slog.Warn("phase3: unmarshal skill procedure", "skill", s.Name, "error", err)
		}
		if len(patternIDs) > 0 {
			pids := make([]string, len(patternIDs))
			for i, pid := range patternIDs {
				pids[i] = pid.String()
			}
			s.PatternIds = &pids
		}
		items = append(items, s)
		if len(items) > limit {
			break
		}
	}
	if rows.Err() != nil {
		return nil, rows.Err()
	}

	if items == nil {
		items = []gen.Skill{}
	}
	return gen.ListSkills200JSONResponse{Items: items}, nil
}

func (s *Server) PatchSkill(ctx context.Context, req gen.PatchSkillRequestObject) (gen.PatchSkillResponseObject, error) {
	if req.Body == nil {
		return nil, fmt.Errorf("%w: request body is required", domain.ErrInvalidInput)
	}

	id, err := s.resolveEntityID(ctx, req.Id)
	if err != nil {
		return nil, err
	}

	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)
	q := sqlcgen.New(tx)

	if req.Body.Status != nil {
		if err := q.UpdateSkillStatus(ctx, sqlcgen.UpdateSkillStatusParams{
			EntityID: id,
			Status:   string(*req.Body.Status),
		}); err != nil {
			if err == pgx.ErrNoRows {
				return nil, fmt.Errorf("%w: skill %s", domain.ErrNotFound, req.Id)
			}
			return nil, err
		}
	}

	// Re-read skill.
	var skill gen.Skill
	var procBytes []byte
	var patternIDs []uuid.UUID
	err = tx.QueryRow(ctx, `
		SELECT entity_id, version, name, procedure, applies_type, action,
		       pattern_ids, status, success_rate, changed_by::text,
		       change_reason, last_used_at
		FROM skills WHERE entity_id = $1 ORDER BY version DESC LIMIT 1`, id).
		Scan(&skill.Id, &skill.Version, &skill.Name, &procBytes, &skill.AppliesType,
			&skill.Action, &patternIDs, &skill.Status, &skill.SuccessRate,
			&skill.ChangedBy, &skill.ChangeReason, &skill.LastUsedAt)
	if err != nil {
		if err == pgx.ErrNoRows {
			return nil, fmt.Errorf("%w: skill %s", domain.ErrNotFound, req.Id)
		}
		return nil, err
	}
	if err := json.Unmarshal(procBytes, &skill.Procedure); err != nil {
			slog.Warn("phase3: unmarshal skill proc", "error", err)
		}
	if len(patternIDs) > 0 {
		pids := make([]string, len(patternIDs))
		for i, pid := range patternIDs {
			pids[i] = pid.String()
		}
		skill.PatternIds = &pids
	}

	actorType, actor := actorInfo(ctx)
	if auditErr := observability.Audit(ctx, q, actorType, actor, "patch",
		&id, "PATCH", "/api/v1/skills/"+req.Id, "",
		map[string]any{"status": req.Body.Status, "pinned_version": req.Body.PinnedVersion}); auditErr != nil {
		return nil, auditErr
	}

	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}

	return gen.PatchSkill200JSONResponse(skill), nil
}

func (s *Server) ListSkillVersions(ctx context.Context, req gen.ListSkillVersionsRequestObject) (gen.ListSkillVersionsResponseObject, error) {
	id, err := s.resolveEntityID(ctx, req.Id)
	if err != nil {
		return nil, err
	}

	rows, err := s.pool.Query(ctx, `
		SELECT entity_id, version, name, procedure, applies_type, action,
		       pattern_ids, status, success_rate, changed_by::text,
		       change_reason, last_used_at
		FROM skills WHERE entity_id = $1
		ORDER BY version DESC`, id)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []gen.Skill{}
	for rows.Next() {
		var skill gen.Skill
		var procBytes []byte
		var patternIDs []uuid.UUID
		if err := rows.Scan(&skill.Id, &skill.Version, &skill.Name, &procBytes, &skill.AppliesType,
			&skill.Action, &patternIDs, &skill.Status, &skill.SuccessRate,
			&skill.ChangedBy, &skill.ChangeReason, &skill.LastUsedAt); err != nil {
			return nil, err
		}
		if err := json.Unmarshal(procBytes, &skill.Procedure); err != nil {
			slog.Warn("phase3: unmarshal skill proc", "error", err)
		}
		if len(patternIDs) > 0 {
			pids := make([]string, len(patternIDs))
			for i, pid := range patternIDs {
				pids[i] = pid.String()
			}
			skill.PatternIds = &pids
		}
		items = append(items, skill)
	}
	if rows.Err() != nil {
		return nil, rows.Err()
	}
	if items == nil {
		items = []gen.Skill{}
	}
	return gen.ListSkillVersions200JSONResponse{Items: items}, nil
}