package llm

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

	"github.com/geo-platform/tenant-api/internal/shared/config"
)

var ErrNotConfigured = errors.New("llm provider is not configured")

type GenerateRequest struct {
	Model           string
	Prompt          string
	Timeout         time.Duration
	MaxOutputTokens int64
	WebSearch       *WebSearchOptions
	ResponseFormat  *ResponseFormat
}

type GenerateResult struct {
	Content string
	Model   string
}

type ResponseFormat struct {
	Type        ResponseFormatType
	Name        string
	Description string
	SchemaJSON  []byte
	Strict      bool
}

type ResponseFormatType string

const (
	ResponseFormatTypeText       ResponseFormatType = "text"
	ResponseFormatTypeJSONObject ResponseFormatType = "json_object"
	ResponseFormatTypeJSONSchema ResponseFormatType = "json_schema"
)

type WebSearchOptions struct {
	Enabled bool
	Limit   int32
}

type Client interface {
	Validate() error
	Generate(ctx context.Context, req GenerateRequest, onDelta func(string)) (*GenerateResult, error)
}

func New(cfg config.LLMConfig) Client {
	provider := strings.ToLower(strings.TrimSpace(cfg.Provider))
	switch provider {
	case "", "disabled":
		return disabledClient{reason: "llm provider is disabled"}
	case "ark":
		return NewArkClient(cfg)
	default:
		return disabledClient{reason: fmt.Sprintf("unsupported llm provider %q", cfg.Provider)}
	}
}

type disabledClient struct {
	reason string
}

func (c disabledClient) Validate() error {
	if c.reason == "" {
		c.reason = "missing LLM configuration"
	}
	return fmt.Errorf("%w: %s", ErrNotConfigured, c.reason)
}

func (c disabledClient) Generate(context.Context, GenerateRequest, func(string)) (*GenerateResult, error) {
	return nil, c.Validate()
}